discman power supply circuit operation manual

COMPACT DISCCOMPACT PLAYER

TECHNICAL THEORYFOR SERVICING

DISCMANPOWER SUPPLY CIRCUIT

OPERATION MANUAL

[photo: D-E705]

— 2 —

Contents

1. POWER SUPPLY CIRCUIT CORRESPONDENCE TABLE ·················································································································· 3

2. OPERATION OF THE D-E705 SERIES POWER SUPPLY CIRCUIT ···································································································· 42-1. Types of Power Supply ········································································································································································ 42-2. Identifying the Power Supplies ··························································································································································· 42-3. Circuit Voltage ····················································································································································································· 52-4. Charging Circuit ·················································································································································································· 152-5. APC Circuit ························································································································································································· 192-6. ESP (Electronic Shock Protection) Circuit ········································································································································· 25

3. OPERATION OF THE D-365 SERIES POWER SUPPLY CIRCUIT ······································································································ 263-1. Types of Power Supply ········································································································································································ 263-2. Identifying the Power Supplies ··························································································································································· 263-3. Circuit Voltage ····················································································································································································· 273-4. Charging Circuit (Operation of the CHARGE MONITOR IC403) ···································································································· 35

4. OPERATION OF THE D-245 SERIES POWER SUPPLY CIRCUIT ······································································································ 364-1. Types of Power Supply ········································································································································································ 364-2. Identifying the Power Supplies ··························································································································································· 364-3. Circuit Voltage ····················································································································································································· 374-4. Charging Circuit ·················································································································································································· 47

5. APPENDIX: TYPES AND APPLICATIONS OF SECONDARY BATTERIES FOR PORTABLE EQUIPMENT(RECHARGEABLE BATTERIES) ··························································································································································· 485-1. Nickel-Cadmium Rechargeable Battery ·············································································································································· 485-2. Nickel-Hydrogen Rechargeable Battery ·············································································································································· 555-3. Lithium-Ion Secondary Battery ··························································································································································· 59

— 3 —

1. POWER SUPPLY CIRCUIT CORRESPONDENCE TABLETable 1-1 shows the power supply circuit correspondence table. This new technical theory for servicing shows the power supply blockdiagrams of the following models among the respective power supply circuit series.

• D-E705 series power supply systemn D-E705• D-365 series power supply systemn D-365• D-245 series power supply systemn D-245

However, among the D-245 series models, those that do not have the ESP circuit do not have the D-RAM IC drive voltage generatorcircuit which is described here in chapter "4. OPERATION OF THE D-245 SERIES POWER SUPPLY CIRCUIT."

Table 1-1 Power supply circuit correspondence table

Power supply circuit series

D-E705 series

D-365 series

D-245 series

Model names

D-E700/E800

D-E705/E805

D-263/265

D-365/375/368/369CK

D-465/475

D-E500/E504

D-140/141/143/141CK/142CK/144K/145/147CR/148CR

D-150AN/151/151C/151V/152CK/152CKT/153/155

D-162CKC/162CKT

D-240/247/242CK/242SK/242CKT/243CK/245

D-330/340/345

D-451SP

D-835K/837K/838K/840K/842K/844K/848K

Reference pages

pages 3 to 25

pages 26 to 35

pages 36 to 47

— 4 —

2. OPERATION OF THE D-E705 SERIES POWER SUPPLY CIRCUIT

2-1. Types of Power SupplyThe D-E705 series compact CD player can be operated on the following three types of power supply.

♦ DC power supply• AC adapter .............................................................................. 4.5 V (supplied)

♦ Battery• Dry cell battery (size AA, 2 pcs) .............................................. 3.0 V (optional), or• Rechargeable nickel-hydrogen battery (NH-DM2AA) ........... 2.4 V (supplied)

2-2. Identifying the Power SuppliesWhen the system controller IC801 is started up, it identifies from where the main power voltage is supplied. It also stops operationif batteries that do not satisfy the specifications are used. The system controller IC identifies the power supplies from the followingthree detections.

(1) Pin %¶[DCINMNT] : The voltage that is obtained by dividing the DCIN input voltage by the resistors.

(2) Pin %•[BATMNT] : The voltage that is obtained by dividing the battery terminal voltage by the resistors.

(3) Pin ̂ ¡[CHGMNT2] : The voltage from the rechargeable battery detection terminal ("H": When the supplied rechargeable battery is inserted)

* 2-1: When a rechargeable battery is inserted, the input of Pin ^¡[CHGMNT2] goes high.

Table 2-1 Power supply identification table

DC supply (from AC adapter)Battery Rechargeable battery

Dry cell battery

Pin %¶[DCINMNT]HLL

Pin %•[BATMNT]HHH

Pin ̂ ¡[CHGMNT2]L (H*2-1)

HL

— 5 —

2-3. Circuit Voltage

Fig. 2-1 Power supply voltage generation block diagram

During AC adaptor drive operation, the following four outputs of the power supply voltage are generated. (Refer to Fig. 2-1.)

1 VIN voltage

• The external voltage input to the DC jack is regulated by the SERIES REGULATOR (Q414, Q402), passed through D407 and outputas the VIN voltage (approx. 4.5 V).

• When the Discman is operated on battery, the battery terminal voltage is supplied as the VIN voltage.

2 VCPU voltage n "POWER CONTROL IC401"

• This voltage is used for driving the system controller IC801, and is 3.0 V.

3 VCC voltage n "2.75 V DC-DC CONVERTER (POWER CONTROL IC401, T401, Q403, Q405, etc.)"

• This voltage is used by the RF AMP IC501, DIGITAL SIGNAL PROCESSOR IC502, COIL/MOTOR DRIVE IC504, etc., and is 2.75 V.

4 VG voltage n "COIL/MOTOR DRIVE IC504"

• This voltage is used by the POWER CONTROL IC401, etc., and is approx. 12 V.

Generation of the respective voltages is described below.

1. Generation of VIN VoltageWhen the DC plug of the AC adapter is connected to the DC jack, the input voltage is regulated by the SERIES REGULATOR (Q414 andQ402), passed through D407 and is output to the POWER CONTROL IC401 and others as the VIN voltage.

3[V]REGULATOR

DCINIC401

POWER CONTROL

2.75[V]DC-DC CONVERTER

IC401,T401,Q403,Q405

12[V]REGULATOR

IC504COIL/MOTOR DRIVE

1 VIN VOLTAGE

2 VCPU VOLTAGE

3 VCC VOLTAGE

4 VG VOLTAGE12[V]

2.75[V]

3[V]

DC VOLTAGEor

BATTERY VOLTAGE

BATTERY

SERIESREGULATOR

Q414,Q402D407

— 6 —

2. Generation of VCPU Voltage

The VCPU voltage generation circuit block diagram is shown in Fig. 2-2.

(1) AC adapter drive operation.

When the DC plug of the AC adapter is connected to the DC jack, the SERIES REGULATOR (Q414, Q402) is turned on and so the VINvoltage (approx. 4.5 V) is sent to pin#º [VIN] of the POWER CONTROL IC401 via D407, which starts up IC401. The VIN voltage isalso sent to pin@™ [VDO] of the POWER CONTROL IC401 via D404. As the POWER CONTROL IC401 is started up, the VCPUvoltage 3.0 V is generated by the SERIES REGULATOR inside IC401. The VCPU voltage thus generated is sent from pin@º [VCPU] topin1 [VDD] and pin$¶ [VDD] of the system controller IC801 to start up the system controller IC801. The POWER CONTROL IC401has a built-in step-up/step-down regulator, but the step-up circuit inside IC401 is not used in AC adapter drive mode because the voltageof 3.3 V or higher is input to pin@™ [VDO] of IC401 all the time. (The switching waveform is not output from pin@¡ [SW] of IC401.)

(2) Battery drive operation

When the battery is inserted, the battery voltage is sent to pin#º [VIN] of the POWER CONTROL IC401 as the VIN voltage to start upIC401. As IC401 starts up, IC401 measures the input voltage at pin@™ [VDO]. IC401 has a built-in VDO voltage detection circuit. IfIC401 detects that the input voltage to pin@™ [VDO] is less than 3.3 V, the PNM wave *2-2 is generated by the SYSTEM CONTROLLERsection inside IC401 and so the switching waveform is output from pin@¡ [SW]. IC401 maintains the input voltage of pin@™ [VDO] to3.3V or higher by the self step-up circuit consisting of the switching output from pin@¡ [SW], L401, D404 and C439 at all times. On theother hand, the input voltage to pin@™ [VDO] of the POWER CONTROL IC401 is sent to the SERIES REGULATOR inside IC401 togenerate the VCPU voltage 3.0 V. The VCPU voltage thus generated is sent from pin@º [VCPU] to pin1 [VDD] and pin$¶ [VDD] ofthe system controller IC801 to start up IC801. The step-up circuit inside IC401 operates only when a Discman is in the STOP mode.When a Discman is in a mode other than the STOP mode, the 2.75 V generator circuit, which is discussed later, starts operation andoutputs the switching waveform from pin@ª [VOUT2] of the POWER CONTROLLER IC401, so the input of pin2 [IN] of the 4 VREGULATOR IC402 is kept to approx. 3.5 V or higher at all times by the step-up circuit consisting of the switching output from pin@ª[VOUT2], Q403, T401, D406, and C418. The output of the step-up circuit changes in the range of approx. 3.5 V to 8 V depending on theconditions of load and power supply. The output voltage that is stepped up to 4 V or higher is input to the 4 V REGULATOR IC402 andis stepped down to 4 V by the SERIES REGULATOR inside IC402. The output voltage in the range of 3.5 V to 4 V is sent to pin@™[VDO] of the POWER CONTROL IC401 via D404 from pin3 [OUT] of IC402 which stops operation of the step-up circuit insideIC401.

*2-2: PNM (Pulse Number Modulation) waveIn the PNM wave, the pulse width is kept constant but the number of pulses is changed, whereas in the PWM wave, the duty ratio of thepulse is changed.

Fig. 2-2 VCPU voltage generation circuit block diagram

— 7 — — 8 —

+

-

+

DCIN

L406

C430

Q402

Q414

R411

C408

D407

+

C428

T401

2

3

IC4024[V] REGULATOR

C418

D406

C439

D404

21

30

VDO

SW

22

3[V]REGULATOR

SYSTEM CONTROLLERSECTION

36

35

R419 C434 INM3

RF3

VCPU GENERATOR

20

VCPU

471

VDD

VDD

IC801SYSTEM CONTROLLER

IC401 POWER CONTROL

R448

BATTERY

17

PCB

27

PCON

TO IC403

VIN

L401

ERRORAMP.

REFERENCEVOLTAGE

OSC

VOLTAGEDETECTOR

SERIES REGULATOR

29VOUT2

Q403

3

4

5

2IN

OUT

+

+

Fig. 2-3 VCC voltage generation circuit block diagram

— 9 — — 10 —

-

VINVOLTAGE

Q403

C424

C423

R428

R427

+

C403

R439C433

R440

L403

Q405 RV401R441

+

C402

VCC VOLTAGE2.75[V]

TO IC8015pin VCCMNT

TP401VCC

29VOUT2 AMP.

COMP.SAW

+- REF

4

5

6

12

C435DTC3

VREF from IC5041pin VG

12[V]

INP2

3

C415R415

RF2

INM

2

SYSTEMCONTROLLER

SECTION

17PCBfrom IC801

27pin PCON

ERROR AMP.

T401

Approx.0.6[V]

OSC

16

SYNC

from IC50246pin 176K176.4[kHz]

(4fs)

IC401 POWER CONTROL

13

4

5

2

4

1

23

-

+

— 11 —

3. Generation of VCC Voltage

Fig. 2-3 shows the VCC voltage generation circuit block diagram.

(1) Operation when the operating mode is switched from STOP mode (SLEEP state) to PLAY mode

(2) Operation when the operating mode is switched from PLAY mode to STOP mode (SLEEP state)

When either the PLAY key of the Discman or the PLAY key or the FF key or the REW key of the remote control is pressed, the systemcontroller IC801 outputs the "L" signal from pin@¶ [PCON]. When "L" is output, the SYSTEM CONTROLLER section inside IC401starts its internal operation. As the SYSTEM CONTROLLER section starts internal operation, the PWM waveform that is generated bythe PWM comparator inside IC401, is output from pin@ª [VOUT2] of the POWER CONTROL IC401. As the PWM waveform is outputfrom pin@ª [VOUT2] of IC401, Q403 and Q405 start the switching operation which starts up the STEP-UP/DOWN DC-DC CONVERTERthat generates 2.75 V. The switching output from Q405 is smoothed out by C403 and is divided by the voltage-divider resistors of R439,RV401, and R440. The output voltage from the voltage-divider resistors is fed back to pin5 [INP2] of IC401. Based on this feedbackvoltage, IC401 controls the duty ratio of the PWM waveform that is generated by the PWM comparator, in order to control the outputvoltage. The switching output from Q405 is at the same time smoothed out by L403 and C402 to generate the VCC voltage (2.75 V ). Asthe VCC voltage is generated, the DSP IC502 starts up so that the 4fs signal is sent to pin!§ [SYNC] of the POWER CONTROL IC401.As the 4fs signal is input to IC401, the SYSTEM CONTROLLER section inside IC401 switches the operation clock to the input 4fssignal from internal oscillation to execute its operation.

When either the STOP key of the Discman or that of the remote control is pressed, the system controller IC801 outputs the "H" signalfrom pin@¶ [PCON]. This "H" signal stops the PWM output from pin@ª [VOUT2] of the POWER CONTROL IC401 to output the "L"signal. This "L" output turns off Q403 and Q405 and stops outputting the VCC voltage. As the VCC voltage is stopped, the 4fs signal isno longer input to pin!§ [SYNC] of the POWER CONTROL IC401. When the SYSTEM CONTROLLER section inside IC401 detectsthat the input to pin!¶ [PCB] goes "H", it stops its internal operation. Note that when the RESUME function is turned off, the systemcontroller IC801 moves the optical pickup to the innermost circumference, and sets the output from pin@¶ [PCON] to "H". When theRESUME function is turned on, the optical pickup is not moved to the innermost circumference.

The waveform timing chart during generation of the VCC voltage is shown in Fig. 2-4.

1 Q403 GATE

2 Q405 COLLECTOR

3 Q405 BASE

4 TP401 VCC

0_

0_

0_

0_

– 12[V]

– 5[V]

– 3[V]

– -7[V]

– 2.75[V]

Fig. 2-4 Waveform timing chart during generation of the VCC voltage

— 12 —

4. Generation of VG voltage

Figure 2-5 shows the VG voltage generation circuit block diagram.

As the VCC voltage 2.75 V is generated as shown, the D/A CONVERTER IC301 starts up. As IC301 starts up, X301 starts oscillating.Then, the 384fs (16.9 [MHz]) signal is supplied to pin&¢ [XIN] of IC502 as the master clock of the DSP IC502 from pin!£ [CKO] ofIC301. Next, when the DSP IC502 starts up, 4fs (176.4 [kHz]) signal is generated from the 384fs signal that is input to pin&¢ [XIN] usingthe frequency-divider inside IC502. Then the 4fs (176.4 [kHz]) signal is output from pin$§ [176K] to pin!§ [SYNC] of the POWERCONTROL IC401. IC401 then outputs the 4fs (176.4 [kHz]) signal (see Fig. 2-6) to the COIL/MOTOR DRIVE IC504. As the 4fs (176.4)[kHz]) signal is input to the COIL/MOTOR DRIVE IC504, the CHARGE PUMP circuit inside IC504 starts functioning and the VGvoltage (approx. 12 V) is generated. Approx. 12 V is output from pin1 [VG] of IC504.Even though the VG voltage is nominally approx. 12 V, it changes in practice depending on the VIN voltage. For information duringrepair, the CHARGE PUMP circuit inside IC504 is judged to be operating correctly when a voltage approximately three times higher thanthe input signal to pin#™ [VCG] of the COIL/MOTOR DRIVE IC504 is output from pin1 [VG] of IC504.

The clock timing during generation of the VG voltage is shown in Fig. 2-6.

Fig. 2-6 Clock timing during generation of the VG voltage

1 IC401 16pin SYNC 0_

2 IC401 15pin CKOUT 0_

– 2.2 V

– -0.4 V

– 4 V

Fig. 2-5 VG voltage generation circuit block diagram

— 13 — — 14 —

VCC VOLTAGE

2.75[V]

77

1

DVDD

AVDD

74

13

CKO

XIN

10

1

17

DVDD

AVDD

XVDD

IC301 D/A CONVERTER

15

16

X30116.8935[MHz]

XTL1

XTL0

461/96176K SYNC

IC502 DSP

30VIN

UNREG

IC401 POWER CONTROL

CKOU

TCL

K

3

CHARGEPUMP

1

23

VGVG

32VCG

UNREG

IC504COIL/MOTOR DRIVE

5VLG

15

16

VG VOLTAGE12[V]

(4fs)

(384

fs)

(4fs

)

1

2

— 15 —

2-4. Charging Circuit

Figure 2-7 shows the charging circuit block diagram.

(1) Operation of the system controller IC801 during chargingWhen the DC plug is connected to the DC jack, the supplied voltage is supplied to the system controller pin%¶ [DCINMNT] of IC801 andPIN#¢ [DCIN] of POWER CONTROL IC401 via D415. Each IC detects that AC adapter is connected. After the system controller IC801starts up and recognizes that AC adapter is connected, the system controller IC801 detects the rechargeable battery by the input terminalof pin^¡ [CHGMHT2] as described below. When the system controller IC801 recognizes that a voltage is input to pin^¡ [CHGMNT2],an "H" signal is output from pin!¡ [CHGON]. POWER CONTROL IC401 starts the charging operation by this "H" signal.

= Rechargeable Battery Detection =The system controller IC801 performs the battery detection by pin^¡ [CHGMNT2]. When the rechargeable battery is inserted (see Fig.2-8(a)), a voltage is input to pin^¡ [CHGMNT2] because cathode of the supplied rechargeable battery is exposed. When an alkaline drycell battery (size AA) is inserted (see Fig.2-8(b)), voltage is not input to pin^¡ [CHGMNT2] because cathode of the battery is molded. Inthe system controller IC801, if no voltage is input to pin^¡ [CHGMNT2] , an "L" signal is output from pin!¡ [CHGON] and the chargingoperation stops. When batteries are inserted as shown in Fig. 2-8(c), voltage is input to pin^¡ [CHGMNT2] of the system controllerIC801. An "L" signal is output from pin!¡ [CHGON] because the system controller IC801 detects that the voltage rise time is fast(Generally, primary cell has a characteristic that the voltage rise time is faster than secondary cell.) and identifies that the inserted batteryis not a rechargeable battery, and an "L" signal is output from pin!¡ [CHGON]. Hence, the charging operation stops.

Fig. 2-8 How to detect the rechargeable battery

TO IC80161pin CHGMNT2


(a)When rechargeable battery is inserted


(Voltage is output because the minus side of the rechargeable

battery is not molded.)

Rechargeable battery detection terminal Rechargeable battery detection terminal

(Voltage is not output because the minus side of the battery

is molded.)

( Voltage is output because the minus side of the rechargeable

battery is not molded.)

Rechargeable battery detection terminal

(b)When alkaline battery is inserted (c)Example of inserting rechargeable battery and alkaline battery

(Detects that the inserted battery is not rechargeable battery because the voltage

rise time is fast.)

(2) Operation of POWER CONTROL IC401 during chargingPOWER CONTROL IC401 contains the CHARGE CONTROL section which starts charging when the charge conditions shown inTable. 2-2 are satisfied. When IC401 starts charging, IC401 outputs the "H" signal from pin#£ [CHGSW]. This "H" signal turns Q401on. At the same time, IC401 outputs the "H" signal inside IC401 to turn on the N-channel MOS FET Q1. As Q401 is turned on, thevoltage that is obtained by I-V converting the current flowing through the recharging battery with external resistors R412 to R414, isinput to pin1 [RS] of IC401. IC401 keeps the current constant at all times through the rechargeable battery by comparing the inputvoltage at pin1 [RS] with the internal reference voltage (0.35 V) with the ERROR AMP. IC401 has a built-in monitor circuit inside theCHARGE CONTROL section which monitors the charging voltage. The monitoring voltage is output to the system controller IC801from pin#¡ [CHGOUT].

During chargingPin #¢[DCIN]

H

InputPin !¶[PCB]

HPin !•[CHGON]

H

OutputPin #£[CHGSW]

H

(3) Operation when stopping chargingDuring charging, the system controller IC801 detects a –∆ V (minus delta V potential) by monitoring the voltages that are input to pin%ª[CHGMNT1] and pin̂ ¡ [CHGMNT2]. When the system controller IC801 detects a –∆ V, it stops charging by setting pin!¡ [CHGON]to "L". In addition to the –∆ V detection system, the system controller IC801 uses the timer system (timer of approx. four hours) at thesame time in order to stop charging.

p –∆ V charging system:This system is most widely used for charging nickel-cadmium and nickel-hydrogen rechargeable batteries. To control charging, thissystem uses the characteristic that the battery voltage reaches its peak at the charge-end, then decreases as the battery temperature risesdue to oxygen gas absorption reaction of the negative electrode. This system is called the –∆V system. Refer to chapter 5 APPENDIX:TYPES AND APPLICATIONS OF SECONDARY BATTERIES FOR PORTABLE EQUIPMENT (RECHARGEABLE BATTERIES).

— 16 —

Table. 2-2 Charge conditions

— 17 — — 18 —

Fig. 2-7 Charging circuit block diagram

+

+ -

+

-+

DCIN

L406

C430

Q402

Q414 R411

C408 D407

Q401

VIN

R419 C434 INM3

RF3

IC401 POWER CONTROL

R448

BATTERY

30

R412 R413 R414

RS

R401 CHGSW

R823

R542

R567

CHGMNT1

D415

DCIN

CHGMNT2

IC403CHARGE MONITOR

18CHGON

11CHGON


("H":during charging)

R433

R434

34

1

32

33

DCINDETECTOR

CHARGECONTROLSECTION

36

35

ERRORAMP

17PCB

27PCON ("H":during charging)

DCINMNT

Q1

(Approx.0.35[V])

61

57 59 31CHGOUT

CHARGEMONITORCIRCUITCHARGE MONITOR

VOLTAGE

BATM

— 19 —

2-5. APC Circuit

Figure 2-9 shows the APC circuit block diagram.

(1) AC adapter drive operation

When the system controller IC801 detects that the PLAY key is pressed, IC801 outputs the "L" signal from pin@¶ [PCON]. When "L" isoutput, the POWER CONTROL IC401 starts its internal operation. As Q411 is turned off, the reference voltage (approx. 2 V) that isobtained by dividing the VCPU voltage by the voltage-divider resistors of R437 and R438, is input to pin9 [INP1] of IC401. When thePOWER CONTROL IC401 starts its internal operation, the switching circuit inside IC401 starts and the APC (Automatic Power Control)circuit also starts so that the feedback voltage to pin8 [INM1] is maintained at 2 V at all times. During AC adapter drive operation, thepower voltage of 4.5 V is input to it, so only the step-down circuit consisting of the switching output from pin@§ [VOUT1] of IC401,Q406, D410, L402, and C437, works. During AC adapter drive operation, the "L" signal is output from pin@¢ [UPCK1] of IC401 whilethe "H" signal is output from pin@∞ [UPCK1B]. Thus the step-up circuit of the APC circuit does not operate (see Fig. 2-10 (1)).


During battery drive operation, the APC circuit is controlled so that the feedback voltage to pin8 [INM1] of IC401 stays at 2 V at alltimes in the same manner as in the AC adapter drive operation. However, the step-up circuit of the APC circuit works when the batteryvoltage decreases. When the battery voltage decreases while the APC circuit is operating, the input voltage to pin8 [INM1] of IC401decreases. As the input voltage to pin8 [INM1] of IC401 decreases, the output voltage from the ERROR AMP inside IC401 (i.e., outputof pin7 [RF1] of IC401) increases which decreases the input voltage to pin!¡ [DTC1]. Hence, the reference input voltage toCOMPARATOR 2 inside IC401 decreases so that a PWM waveform having a high duty ratio is output from COMPARATOR 2. ThePWM waveform thus generated is output from pin@¢ [UPCK1] and pin@∞ [UPCK1B] (see Fig. 2-10 (2)). Then Q407 and Q408 startswitching operation and the step-up circuit is activated. The APC circuit functions so that the feedback voltage to pin8 [INM1] stays at2 V at all times.

The Discman power supply has a built-in protection circuit that protects the laser diode from damage in case the power supply suffers amomentary failure. When the power supply is momentarily shut down, Q417 is turned on and so the voltage that is obtained by dividingthe VCPU voltage by the voltage-divider resistors of R422 and R432, is sent to Q411 which turns on Q411. This decreases the referencevoltage input to the APC circuit, i.e., pin9 [INP1] that protects the laser diode from damage.

Figure 2-10 shows the operation waveforms of the APC circuit during battery drive operation.

Describing the APC operation in more detail, the APC circuit operation maintains the PD value to 150 mV using a feedback loop insidethe RF AMP IC501. When the PD value is 150 mV, the input voltage to pin8 [INM1] of POWER CONTROL IC401 becomes approx.2 V.

— 20 —

— 21 — — 22 —

Fig. 2-9 APC circuit block diagram

SAW

7 +-

REF

6

IC501RF AMP.

PD R451

R417

C416

R418

INM18

+-

7

9

VREF

12

6C435

VREF

DTC3

+-

R420

CMP1

R430 C429

VCPU

R442 R443

11DTC1

R423

R444VCPU3[V]

VINVOLTAGE

Q406

Q408

Q407

L402D410

L404 L405

+ +

C437 C420

TP411IOP+

R4382.2M

C432

R4040

R4371M

VCPU3[V]

from IC80127pin PCON

VINVOLTAGE

R432

R422 VCPU3[V]

IC401POWER CONTROL

INP1

RF1

COMP.1+-

Q410

Q409

Q411

Q417

OPTICALPICK-UP BLOCK

(DAX-11D)

LD

PD

C438

ERRORAMP.

COMP.1

STEP-DOWN SWITCHING CIRCUIT

STEP-UP SWITCHING CIRCUIT

START-UP

SYSTEMCONTROLLER

SECTION

17

PCB

(2[V

])

R424

VOUT1

UPCK1

UPCK1B

30 VIN VINVOLTAGE

10

26

24

25

1

2

3

R402

-

— 23 — — 24 —

Fig. 2-11 ESP (Electronic Shock Protection) circuit block diagram

ADPCMENCODER

RF AMP.26

27

28

25

(A+B+C+D)16

IC501RF AMP.

EFM EFM3

68

70

69

DSPSECTION 13

11

LRCK

BCLK

DATA

LRCI

BCKI

DATI

12

I/F

D-RAM CONTROLLER

ADPCMDECODER

16bit→5bit 5bit→16bit

I/F

15

14

I/F

26 24 25 21

SCLK

XLT

SDTI

SDTO

41 37 39 40


SCK

XLT

SDTO

SDTI

16

LRCO

BCKO

DATO

LRCK

BCK

DATA

24

IC301D/A CONVERTER

74

XIN

9

CLK

(384fs)

IC601D-RAM CONTROLLER

IC502DSP

5,9-12,14-18

35-44A0-A9

29-32D0-D3

IC602 D-RAM

1-2,24-25A0-A9 D0-D3

37 TP510WFCK

7.35[kHz]:during ESP OFF12.6[kHz]:during ESP ON

16

15X301

16.9[MHz](384fs)

XTLI

XTLO

CKO

DETE

CTOR

OPTICAL PICK-UPBLOCK

DAX-11D

26

44

RW

RW

24CDATA

42

CDAT

A

41

SQCK

25SQCK

I/F

22

23

D/ACONV.

LO

RO

L-ch

R-ch

9

5

13

(NOTE:when servo operationis stable.)

C

B

D

A

— 25 —

2-6. ESP (Electronic Shock Protection) Circuit

Figure 2-11 shows the ESP (Electronic Shock Protection) circuit block diagram.

(1) Generation of DA DATA

The signals of A to D that are picked up by the detectors of the optical pickup, are input to the RF AMP IC501 where the EFM signal isgenerated by the RF AMP inside IC501. The EFM signal thus generated is output to pin3 [EFM] of the DSP IC502 from pin!§ [EFM]of IC501. In the DSP IC502, various signal processing (14-8 demodulation, de-interleaving, error correction, etc.) is performed on theinput EFM signal to generate the DA DATA. The DA DATA thus generated is output to the D-RAM CONTROLLER IC601 with the L-ch data and the R-ch data alternately, in synchronization with LRCK (L-channel/R-channel discrimination signal) that is output frompin^• [LRCK] of DSP IC502, and also in synchronization with BLCK (bit clock) that is output from pin&º [BCLK]. The BCLK (48fs)and LRCK (fs) signals that are generated by the DSP IC502, are generated by a frequency-divider inside IC502 based on the 384fs signalthat is input to pin&¢ [XIN].

(2) Operation of the D-RAM CONTROLLER IC601

Operation of the D-RAM CONTROLLER IC601 when the ESP function is on is as follows. The DA DATA that is input to the D-RAMCONTROLLER IC601 when the ESP function is on, is input to ADPCM ENCODER inside IC601, and is compressed to 5-bit data. TheDA DATA compressed to 5-bit data is sequentially stored in the D-RAM IC602 through the D-RAM CONTROLLER block insideIC601. Then the 5-bit data that is read from the D-RAM IC602 enters the ADPCM DECODER block where it is decoded to 16-bit data.The DA DATA thus decoded is output to the D/A CONVERTER IC301 with the L-ch data and the R-ch data alternately, in synchronizationwith LRCK (L-channel/R-channel discrimination signal) that is output from pin!∞ [LRCO] of IC601, and also in synchronization withBLCK (bit clock) that is output from pin!¢ [BCKO].Next, operation of the D-RAM CONTROLLER IC601 when the ESP function is off, is described. When the D-RAM CONTROLLERIC601 recognizes that the ESP function is turned off by the commands (refer to the commands described below) that are sent from thesystem controller IC801, the switches in IC601 are activated to set the internal operation of the Discman to the pass-through state. Then,the DA DATA is output to the D/A CONVERTER IC301 with the L-ch data and the R-ch data alternately, in synchronization with LRCK(L-channel/R-channel discrimination signal) that is output from pin!∞ [LRCO] of IC601, and also in synchronization with BLCK (bitclock) that is output from pin!¢ [BCKO].Here, the BCLK (48fs) and LRCK (fs) signals that are generated by DSP IC601, are generated by a frequency-divider inside IC601 basedon the 384fs signal that is input to pin9 [CLK]. The BCLK and LRCK signals that are generated inside DSP IC502 are in synchronizationwith the BCLK and LRCK signals that are generated by the D-RAM CONTROLLER IC601.

♦ Interface between the system controller IC801 and the D-RAM CONTROLLER IC601

= From the system controller IC801 n D-RAM CONTROLLER IC601 =• Turning ON and OFF the ESP• Turning ON and OFF the ADPCM ENCODER block and the ADPCM DECODER block.

= From the D-RAM CONTROLLER IC601 n system controller IC801• Data writing status of the D-RAM IC602 (availability of the data writing area inside the D-RAM IC602, etc.)

(3) Generation of Analog Signal

The DA data that is sent to the D/A CONVERTER IC301 is D/A converted by the D/A CONVERTER inside IC301, and is output frompin9 [LO] and pin5 [RO] as the L-ch and the R-ch analog signal.

— 26 —

3. OPERATION OF THE D-365 SERIES POWER SUPPLY CIRCUIT

3-1. Types of Power Supply

The D-365 series compact CD player can be operated on the following three types of power supply.

♦ DC power supply• AC adapter .................................................................................4.5 V (supplied)

♦ Battery• Dry cell battery (size AA, 2pcs) ................................................ 3.0 V (optional), or• Rechargeable nickel-hydrogen battery (BP-DM20) .................. 2.4 V (supplied)

3-2. Identifying the Power Supplies

When the system controller IC801 is started up, it identifies from where the main power voltage is supplied. It also stops operation ifbatteries that do not satisfy the specifications are used. The system controller IC identifies the power supplies from thefollowing three detections.

(1) Pin %¶[DCINMNT] : The voltage that is obtained by dividing the DCIN input voltage by the resistors.

(2) Pin %•[BATMNT] : The voltage that is obtained by dividing the battery terminal voltage by the resistors.

(3) Pin #™[XRCHG] : The result of the rechargeable battery detection switch ("L": When the rechargeable battery is inserted)

DC supply (from AC adapter) Battery Rechargeable battery

Dry cell battery

Pin %¶[DCINMNT]HLL

Pin %•[BATMNT]HHH

Pin #™[XRCHG]H (L*3-1)

LH


* 3-1: When a rechargeable battery is inserted, the input of pin #™[XRCHG] goes low.

— 27 —


During AC adapter drive operation, the following five outputs of the power supply voltage are generated. (Refer to Fig. 3-1.)

1 UNREG voltage• The UNREG voltage that is supplied to the DC jack from the AC adapter, which is 4.5 V.• When the Discman is operated on battery, the battery terminal voltage is supplied as the UNREG voltage through D411.

2 VCPU voltage n "RESET IC406"• This voltage drives the system controller IC801, and is 3.0 V.

3 REG. 3 V voltage n "SERIES REGULATOR (Q404, Q403)"• The voltage that is supplied to the DC jack from external AC adapter, is regulated by the SERIES REGULATOR (Q404, Q403), and is supplied as the REG. 3 V voltage.• When the Discman is operated on battery, the battery terminal voltage is supplied as the REG. 3 V voltage through D411.

4 VCC voltage n "2.75 V DC-DC CONVERTER (SWITCHING REGULATOR IC401, T401, Q401, Q402 etc.)"• This voltage is used by the RF AMP IC501, DIGITAL SIGNAL PROCESSOR IC502, COIL/MOTOR DRIVE IC504, etc., and is 2.75 V.

5 VG voltage n "STEP-UP DC-DC CONVERTER (SWITCHING REGULATOR IC401, T401, D413, C561)"• This voltage is used the power supply of the pre-driver inside IC504, and is approx. 12 V.



IC401,IC409T401,Q401,Q402

STEP-UPDC-DC CONV.

IC401,T401,D413,C561

4 VCC VOLTAGE

5 VG VOLTAGE12[V]

DCIN3 REG.3V VOLTAGE

DC VOLTAGEor

BATTERY VOLTAGE

BATTERY

SERIESREGULATOR

Q404,Q403

D4033[V]

REGULATOR

3[V]

D401

D411

2 VCPU VOLTAGE

IC406RESET(3[V] REG.)

1 UNREG VOLTAGE

REG.3V VOLTAGEor

BATTERY VOLTAGE

2.75[V]

— 28 —





When the DC plug of the AC adapter is connected to the DC jack, approx. 4.5 V is sent to pin6 [VDD] of the RESET IC401 via D403and D411, which starts up the RESET IC406. As IC406 is started up, the VCPU voltage 3.0 V is generated by the SERIES REGULATORinside the RESET IC406. The VCPU voltage thus generated is sent from pin5 [VOUT] to pin1 [VDD] and pin$¶ [VDD] of the systemcontroller IC801 to start up the system controller IC801.


When the battery is inserted, the battery voltage is sent to pin6 [VDD] of the RESET IC406 via D411 to start up the RESET IC406. TheRESET IC406 has a built-in VDD voltage detection circuit so that the input voltage to pin6 [VDO] is at all times maintained at 3.3 V orhigher by the self step-up operation using the switching output from pin8 [LX], L402, D406 and C416. On the other hand, the inputvoltage to pin6 [VDD] of the RESET IC406 is input to the SERIES REGULATOR inside IC406 to generate the VCPU voltage 3.0 V.The VCPU voltage thus generated is sent from pin5 [VOUT] to pin1 [VDD] and pin$¶ [VDD] of the system controller IC801 to startup IC801. The step-up circuit inside IC401 operates only when a Discman is in the STOP mode because the step-up circuit of the RESETIC406 has a large power consumption. When a Discman is in the PLAY mode, the 2.75 V generator circuit, which is discussed later,starts operation. Q411 (1/2) and Q411 (2/2) are turned on by this VCC voltage so that the REG. 3 V signal is input to pin2 [CE/] of theRESET IC406. The step-up circuit inside IC406 is set into the STOP state by this input signal. The output voltage (3.6 V or higher) thatis obtained by the step-up circuit consisting of the switching output from pin5 [OUT] of IC401, Q402, T401, D407 and C416, issupplied to pin6 [VDD] of the RESET IC406 to generate the stable VCPU voltage even though the step-up circuit of IC406 does notoperate.

— 29 —

Fig

. 3-2

VC

PU

vol

tage

gen

erat

ion

circ

uit b

lock

dia

gram

BATT

ERY

DCIN

L406 C4

30

D403

+

C408

T401

LX

VCPU

GENE

RATO

R

VCPU

VOL

TAGE

L402

D411

R460

8

D406

CS/

+

C416

6 3[V]

REGU

LATO

R

5

VOLT

AGE

DETE

CTOR

&CO

NTRO

LSE

CTIO

N2

IC40

6RE

SET(

3[V]

REG

.)

D407

REG.

3VVO

LTAG

E

471VDD

VDD

IC80

1SY

STEM

CON

TROL

LER

VOUT

VCC

VOLT

AGE

2.75

[V]

Q411

(1/2

)

Q411

(2/2

)

VDD

Q402fro

m IC

401

5pin

OUT

— 30 —



(1) Operation when the operating mode is switched from STOP mode (SLEEP state) to PLAY mode

When either the PLAY key of the Discman or the PLAY key or the FF key or the REW key of the remote control is pressed, the systemcontroller IC801 outputs the "L" signal from pin@¶ [PCON]. When "L" is output, Q415 and Q412 are turned on by this "L" signal so thatthe input to pin2 [CTL] of the SWITCHING REGULATOR IC401 is set to "L" to start the SWITCHING REGULATOR IC401. As theSWITCHING REGULATOR IC401 starts, the internal oscillator of IC401 starts oscillating so that the PWM waveform that is generatedby the PWM comparator inside IC401, is output from pin5 [OUT] of the SWITCHING REGULATOR IC401. As the PWM waveformis output from pin5 [OUT] of IC401, Q402 and Q401 start the switching operation which starts up the STEP-UP/DOWN DC-DCCONVERTER that generates 2.75 V. The switching output from Q401 is smoothed out by L401 and C403, and is divided by the voltage-divider resistors of R401, RV401, and R402. The output voltage from the voltage-divider resistors is fed back to pin1 [IN] of IC401.Based on this feedback voltage, IC401 controls the duty ratio of the PWM waveform that is generated by the PWM comparator, in orderto control the output voltage, then to generate the VCC voltage (2.75 V).

(2) Operation when the operating mode is switched from PLAY mode to STOP mode (SLEEP state)

When either the STOP key of the Discman or that of the remote control is pressed, the system controller IC801 outputs the "H" signalfrom pin@¶ [PCON]. Q412 is turned off by this "H" signal which stops the SWITCHING REGULATOR IC401, and stops outputting theVCC voltage 2.75 V. Note that when the RESUME function is turned off, the system controller IC801 moves the optical pickup to theinnermost circumference, and sets the output from pin@¶ [PCON] to "H". When the RESUME function is turned on, the optical pickupis not moved to the innermost circumference.


1 Q402

GATE

2 Q401

COLLECTOR3 Q401 BASE

4 TP401 VCC

– 2.8 V

0_

0_

0_

0_

– 3.2 V

– 3 V

– -5 V

– 2.75 V


— 31 —

Fig

. 3-3

VC

C v

olta

ge g

ener

atio

n ci

rcui

t blo

ck d

iagr

am

+

+

ERRO

R AM

PPW

M C

OMP

5

R401

C802

from

IC80

1

27pi

n PC

ON

PRED

RIVE

R

17

0.5[

V]

3

VCC

OUT

OSC

IN

RV40

1

2.75

[V]

+

C403

IC40

1 SW

ITCH

ING

REGU

LATO

R

APPR

OX. 0

.5[V

]

2CTL

Q412

Q303

Q415

R458

R459

1 2

5

D415

R404

R403

L401

+

C402

R402

Q401

Q402

C404

T401

VCPU

3[V]

R409

VREF

BATT

ERY

DCIN

Q403

,Q40

4

C443

IC40

9W

AVE

SHAP

ED(A

ND G

ATE)

4

TO IC

406

6pin

VDD

D407

+

C416

1

23

TP40

1VC

C4

SERI

ESRE

GULA

TOR

--

— 32 —



Figure 3-5 shows the VG voltage generation circuit block diagram. When the PLAY key is pressed, the system controller IC801outputs the "L" signal from pin@¶ [PCON]. When "L" is output, Q415 and Q412 are turned on by this "L" signal so that the inputto pin2 [CTL] of the SWITCHING REGULATOR IC401 is set to "L" to start the SWITCHING REGULATOR IC401. As theSWITCHING REGULATOR IC401 starts, the internal oscillator of IC401 starts oscillating so that the PWM waveform that isgenerated by the PWM comparator inside IC401, is output from pin5 [OUT] of the SWITCHING REGULATOR IC401. As thePWM waveform is output from pin5 [OUT] of IC401, the STEP-UP DC-DC CONVERTER consisting of T401, D413, C411,C561 and the output switching waveform, starts to generates the VG voltage (approx. 12 V) from the REG. 3 V. The VG voltagethus generated, is output to pin#§ [VG] of the COIL/MOTOR DRIVE IC504.

5

from IC80127pin PCON

OUT

IC401 SWITCHING REGULATOR

2

CTL

Q412

Q303

Q415

R458

R459

1

2

5

D415

R404

Q402

C404T401

VCPU3[V]

C443

IC409WAVE SHAPED

(AND GATE)

4

1

C405C442

VCCVOLTAGE

2.75[V]

D413

+

C411

C441

TO IC50436pin VG

VG VOLTAGE12[V]

Q401

1

0.2[V]

3.4[V]

0

Approx.203[kHz]

+

C561

REG.3VVOLTAGE

Fig. 3-6 Charging circuit block diagram

— 33 — — 34 —

BATTERY

DCIN

D401 D412 R429

R431 R430

Q409R429

Q404

Q403

R424

D403

R419R420

C421

R425 D410

R421R422R423

R426

R418

VCPUVOLTAGE3[V]

R417

R454

R414

Q408(1/2)

Q408(2/2)

R413

1

R410 C418

R412

3

R416 R415C419

D414

R427

R457

R411

IC403CHARGE MONITOR

Q405

Q406

Q410(1/2)

Q410(2/2)11

59CHGMNT

CHGON


32

S802

XRCH

G

R823

ERRORCOMP1

ERRORCOMP2

CHARGEMONITOR

CHARGECONTROLLER

("L":during charging)

("H":during charging)Q407

DC IN4.5[V]

R432

R433

6

7

5

8

2

(During STOP state:2.0[V])(During charging :2.4[V])

R542

R567

57DCINMNT

27PCON

+ -+-

— 35 —

3-4. Charging Circuit (Operation of the CHARGE MONITOR IC403)


(1) Operation of the system controller IC801 during charging

When the DC plug is connected to the DC jack, the system controller IC801 starts up. When the system controller IC801 starts up, thesystem controller IC801 detects if the Discman satisfies the following charging conditions or not. After the system controller IC801recognizes that the following conditions are satisfied, it outputs the "L" signal from pin!¡ [CHGON]. Q408 (1/2), Q406 and Q405 areturned on by this "L" signal so that the negative (-) terminal of a battery is connected to ground. At the same time, Q409 and Q410 (1/2)are turned on which starts charging.

♦ Charging conditions1. The Discman operates on DC (output from AC adapter) n pin%¶ [DCINMNT] of system controller IC801: "H"2. The rechargeable battery (BP-DM20) is inserted in the Discman n pin#™ [XRCHG] of system controller IC801: "L"3. The Discman is in the STOP state n pin@¶ [PCON] of system controller IC801 outputs the "H" signal.

(2) Operation when charging

When charging starts, the reference voltage that is input to pin6 of the CHARGE MONITOR IC403 becomes approx. 2.4 V. At the sametime, the voltage that is obtained by I-V converting the current flowing through the rechargeable battery with external resistors R431 andR430, is input to pin5 of IC403. The ERROR COMPARATOR1 inside IC403 keeps the charging current that flows through therechargeable battery constant at all times by comparing the input voltage at pin5 with the reference voltage (approx. 2.4 V) and bycontrolling the pin7 output. The CHARGE MONITOR IC403 has an internal ERROR COMPARATOR 2 which monitors the chargevoltage that is charged to the rechargeable battery with the MONITOR circuit. The monitoring voltage is output to the system controllerfrom pin%ª [CHGOUT] of IC801.

(3) Operation when stopping charging

During charging, the system controller IC801 detects a –∆ V (minus delta V potential) by monitoring the voltages that are input to pin%ª[CHGMNT]. When the system controller IC801 detects a –∆ V, it stops charging by setting pin!¡ [CHGON] to "H". In addition to the–∆ V detection system, the system controller IC801 uses the timer system (timer of approx. three hours) at the same time in order to stopcharging.

(4) Operation of the CHARGE MONITOR IC403 during playback

During playback, the COMPARATOR1 inside the CHARGE MONITOR IC403 functions as the SERIES REGULATOR. First, whenthe PLAY key is pressed, the system controller IC801 outputs the "L" signal from pin@¶ [PCON]. When "L" is output, Q408 (2/2) andQ410 (2/2) are turned on by this "L" signal so that the reference voltage (approx. 2.4 V) is input to pin6 of the CHARGE MONITORIC403. At the same time, a voltage passed through the SERIES REGULATOR which consists of Q403 and Q404 is input to pin5 ofIC403 after divided by R426, R422 and R421. The ERROR COMPARATOR1 inside IC403 controls the output from pin7 to keep theoutput voltage from the SERIES REGULATOR to be constantly 3.0V (REG.3V voltage) by comparing the input voltage to pin5 withthe input voltage to pin6.

— 36 —

4. OPERATION OF THE D-245 SERIES POWER SUPPLY CIRCUIT

4-1. Types of Power Supply

The D-245 series compact CD player can be operated on the following three types of power supply.

♦ DC power supply• AC adapter ................................................................................................. 4.5 V (supplied)

♦ Battery• Dry cell battery (size AA, 2 pcs) ............................................................... 3.0 V (optional), or• Rechargeable nickel-hydrogen cadmium battery (BP-DM10) .................. 2.4 V (supplied)

4-2. Identifying the Power Supplies

When the system controller IC801 is started up, it identifies from where the main power voltage is supplied. It also stops operation ifbatteries that do not satisfy the specifications are used. The system controller IC identifies the power supplies from the following threedetections.

(1) Pin @ª[DCINMNT] : The voltage that is obtained by dividing the DCIN input voltage by the resistors.

(2) Pin @£[BATMNT] : The voltage that is obtained by dividing the battery terminal voltage by the resistors.

(3) Pin !∞[XRCHG] : The result of the rechargeable battery detection switch ("L": When the rechargeable battery is inserted)


* 4-1: When a rechargeable battery is inserted, the input of pin !∞[XRCHG] goes low.

DC supply (from AC adapter)Battery Rechargeable battery

Dry cell battery

Pin @ª[DCINMNT]HLL

Pin @£[BATMNT]HHH

Pin !∞[XRCHG]H (L*4-1)

LH

— 37 —



During AC adapter drive operation, the following five outputs of the power supply voltage are generated. (Refer to Fig. 4-1.)

1 VIN voltage• The external voltage input to the DC jack is regulated by the SERIES REGULATOR (Q404, Q402), and output as the VIN voltage (approx. 4.5 V).• When the Discman is operated on battery, the battery terminal voltage is supplied as the VIN voltage.

2 VCPU voltage n "POWER CONTROL IC401"• This voltage drives the system controller IC801, and is 3.0 V.

3 VCC voltage n "3.2 V DC-DC CONVERTER (POWER CONTROL IC401, T401, Q401, Q402, etc.)"• This voltage is used by the RF AMP IC501, DIGITAL SIGNAL PROCESSOR IC601, COIL/MOTOR DRIVE IC701, etc., and is 3.2 V.

4 VG voltage n "POWER CONTROL IC401"• This voltage is used by the COIL/MOTOR DRIVE IC701, etc., and is approx. 12 V.

5 D-RAM IC503 drive voltage n "5 V REG. IC402"• This voltage is used to drive the D-RAM IC503, and is approx. 5.0 V.


1. Generation of VIN Voltage

When the DC plug of the AC adapter is connected to the DC jack, the input voltage is regulated by the SERIES REGULATOR (Q404 andQ403), passed through D401 and is output to the POWER CONTROL IC401 and others as the VIN voltage.

DCIN

IC401POWER CONTROL

IC401,T401,Q401,Q402

1 VIN VOLTAGE

2 VCPU VOLTAGE

3 VCC VOLTAGE

4 VG VOLTAGE12[V]

3.2[V]

3[V]

DC VOLTAGEor

BATTERY VOLTAGE

BATTERY

SERIESREGULATOR

Q404,Q403

3[V]REGULATOR

IC601DSP

CHARGEPUMP

IC401POWER CONTROL


4fs

IC401,T401,D405,C4225[V]SERIES

REGULATOR

IC4025[V] REG.

5 5[V] for D-RAM IC503STEP-UPDC-DC CONVERTER

— 38 —




When the DC plug of the AC adapter is connected to the DC jack, the SERIES REGULATOR (Q404, Q403) is turned on and so the VINvoltage (approx. 4.5 V ) is sent to pin#º [VIN] of the POWER CONTROL IC401 via D401, which starts up IC401. The VIN voltage isalso sent to pin@£ [VDO] of the POWER CONTROL IC401 via D404. As the VIN voltage is input to pin@£ [VDO] of the POWERCONTROL IC401, the VIN voltage is sent to the SERIES REGULATOR inside IC401 which generates the VCPU voltage 3.0 V. TheVCPU voltage thus generated is sent from pin@º [VCPU] to pin&™ [VDD] of the system controller IC801 to start up the systemcontroller IC801. The POWER CONTROL IC401 has a built-in step-up/step-down regulator, but the step-up circuit inside IC401 isturned off in AC adapter drive mode.


When the battery is inserted, the battery voltage is sent to pin#º [VIN] of the POWER CONTROL IC401 as the VIN voltage to start upIC401. As IC401 starts up, IC401 measures the input voltage at pin@£ [VDO]. IC401 has a built-in VDO voltage detection circuit. IfIC401 detects that the input voltage to pin@£ [VDO] is less than 3.3 V, the PNM wave is generated by the SYSTEM CONTROLLERsection inside IC401 and so the switching waveform is output from pin@™ [SW]. The input voltage is at all times maintained at 3.3 V orhigher by the self step-up operation using the switching output from pin@™ [SW], L402, D404 and C417. On the other hand, the inputvoltage to pin@£ [VDO] of the POWER CONTROL IC401 is sent to the SERIES REGULATOR inside IC401 to generate the VCPUvoltage 3.0 V . The VCPU voltage thus generated is sent from pin@º [VCPU] to pin&™ [VDD] of the system controller IC801 to start upIC801. The step-up circuit inside IC401 operates only when a Discman is in the STOP mode. When a Discman is in a mode other thanthe STOP mode, the VCC generator circuit, which is discussed later, starts operation and outputs the switching waveform from pin@ª[VOUT1] of the POWER CONTROLLER IC401. The voltage 3.3 V or higher (approx. 3.8 V when the battery voltage is 3 V) isgenerated by the step-up circuit consisting of the switching output from pin@ª [VOUT1] of IC401, Q402, T401, D407 and C417. Thestepped-up voltage is sent to pin@£ [VDO] of the POWER CONTROL IC401 which stops operation of the step-up circuit inside IC401.When the Discman runs on battery, the stepped-up voltage that is generated by the above described step-up circuit is sent to pin@£[VDO] of the POWER CONTROL IC401 so that the current consumption is suppressed by shorting the on period of the step-up circuitinside IC401.

— 39 — — 40 —

Fig. 4-2 VCPU voltage generation circuit block diagram

+

-

+

DCIN

C412

Q404REG.

R418

D401

D404

22

30

VDO

SW

23

3[V]REGULATOR

SYSTEM CONTROLLERSECTION

R407

C426 INM2

RF2

VCPU GENERATOR

20

VCPU

72

VDD


IC401 POWER CONTROL

BATTERY

17

PCB

PCON

VCPUVOLTAGE

3[V]

VIN

L402

ERRORAMP.

REFERENCEVOLTAGE

OSC

VOLTAGEDETECTOR

R408

Q403

R420

3

4

35VOUT2

C429

C417

6

SERIES REGULATOR

29VOUT1Q402

D407UNREG

VOLTAGE6 2

9

T401

1

— 41 —



(1) Operation when the operating mode is switched from STOP mode (SLEEP state) to PLAY modeWhen either the PLAY key of the Discman or the PLAY key or the FF key or the REW key of the remote control is pressed, the systemcontroller IC801 outputs the "L" signal from pin6 [PCON]. When "L" is output, the SYSTEM CONTROLLER section inside IC401starts its internal operation. As the SYSTEM CONTROLLER section starts internal operation, the PWM waveform that is generated bythe PWM comparator inside IC401, is output from pin@ª [VOUT1] of the POWER CONTROL IC401. As the PWM waveform isoutput from pin@ª [VOUT1] of IC401, Q402 and Q401 start the switching operation which starts up the STEP-UP/DOWN DC-DCCONVERTER that generates 3.2 V. The switching output from Q401 is smoothed out by C403 and is divided by the voltage-dividerresistors of R401, R402, and R421. The output voltage from the voltage-divider resistors is fed back to pin7 [INP1] of IC401. Basedon this feedback voltage, IC401 controls the duty ratio of the PWM waveform that is generated by the PWM comparator, in order tocontrol the output voltage. The switching output from Q401 is at the same time smoothed out by L401 and C402 to generate the VCCvoltage (3.2 V). As the VCC voltage is generated, the DSP IC601 starts up so that the 4fs signal is sent to pin!§ [SYNC] of the POWERCONTROL IC401. As the 4fs signal is input to IC401, the SYSTEM CONTROLLER section inside IC401 switches the operationclock to the input 4fs signal from internal oscillation to excuse its operation.

(2) Operation when the operating mode is switched from PLAY mode to STOP mode (SLEEP state)When either the STOP key of the Discman or that of the remote control is pressed, the system controller IC801 outputs the "H" signalfrom pin6 [PCON]. This "H" signal stops the PWM output from pin@ª [VOUT1] of the POWER CONTROL IC401 which outputs the"L" signal. This "L" output turns off Q402 and Q401 and stops outputting the VCC voltage. As the VCC voltage is stopped, the 4fssignal is no longer input to pin!§ [SYNC] of the POWER CONTROL IC401. When the SYSTEM CONTROLLER section insideIC401 detects that the input to pin!¶ [PCB] goes "H", it stops its internal operation. Note that when the RESUME function is turnedoff, the system controller IC801 moves the optical pickup to the innermost circumference, and sets the output from pin6 [PCON] to"H". When the RESUME function is turned on, the optical pickup is not moved to the innermost circumference.



— 42 —

Fig

. 4-3

VC

C v

olta

ge g

ener

atio

n ci

rcui

t blo

ck d

iagr

am

- SAW

- +

ERRO

R AM

PPW

M C

OMP.

R401

R402

+

C403

R404

R403

L401

Q401

Q402

BATT

ERY

DCIN

Q404

,Q40

3SE

RIES

REGU

LATO

R6

2

91

T401

R421

REF

7

VOUT1

INP1

IC40

1PO

WER

CON

TROL

VCC

VOLT

AGE

3.2[

V]

+

C402

D407

TO IC

401

22pi

n VD

O

SYST

EMCO

NTRO

LLER

SECT

ION

17PC

Bfro

m IC

801

6pin

PCO

NOS

C

SYNCfro

m IC

601

68pi

n W

DCK

176.

4[kH

z](4

fs)

16

(Approx.0.6[V])

29

1

23

TP40

2VC

C4

+

-


— 43 —


Figure 4-5 shows the VG voltage generation circuit block diagram.As the VCC voltage 3.2 V is generated as shown, the D/A CONVERTER IC301 starts up. As IC301 starts up, X301 starts oscillating. Then,the 384fs (16.9 [MHz]) signal is supplied to pin&§ [XIN] of IC601 as the master clock of the DSP IC601 from pin!£ [CKO] of IC301. Next,when the DSP IC601 starts up, 4fs (176.4[kHz]) signal is generated from the 384fs signal that is input to pin&§ [XIN] using the frequency-divider inside IC601. Then the 4fs (176.4 [kHz]) signal is output from pin^• [WDCK] to pin!§ [SYNC] of the POWER CONTROL IC401.When the 4fs signal is input to the system controller section inside the POWER CONTROL IC401, the system controller section switchesthe operation clock to the input 4fs signal from internal oscillation. As the 4fs signal is input to the CHARGE PUMP circuit, the CHARGEPUMP circuit starts functioning* 4-2 and the VG voltage (approx. 12 V) is generated. The VG voltage thus generated, is output from pin@•[VG] of to the COIL/MOTOR DRIVE IC701. This VG voltage is also used for internal operation of IC401.

*4-2: The 4fs signal is the signal for synchronization and has nothing to do with the operation of CHARGE PUMP.

24

25

26

C418 C419

27C2H

C2L

C1L

C1HCHARGEPUMP

SYSTEMCONTROLLER

SECTION

17PCBIC801

SYSTEM CONTROLLER

6PCON

15SYCSLESP

22

16OSC

WDCK

IC601DSP

76XI

N

13

CKO

(384

fs)

15

16

XTLI

XTLO

X30116.9[MHz]

(384fs)

IC301D/A CONVERTER

1/96 68(4fs)

SYNC

VG

TOCOIL/MOTOR DRIVE IC701

VG VOLTAGE12[V]

IC401 POWER CONTROL

78DVDD

1

1AVDD

DVDD

10AVDD

VCCVOLTAGE

3.2[V]

28VG VOLTAGE

C420

30

VIN

VINVOLTAGE

(4fs)

5. Generation of the D-RAM IC503 drive voltage

— 44 —

Fig. 4-6 D-RAM IC503 drive voltage generation circuit block diagram

The D-RAM IC503 drive voltage generation circuit block diagram is shown in Fig. 4-6. When the PLAY key is pressed, the systemcontroller IC801 outputs the "L" signal from pin6 [PCON]. When "L" is output, the system controller section inside the POWER CONTROLIC401 starts up and outputs the switching waveform from pin@ª [VOUT1] of IC401. As the switching waveform is output from pin@ª[VOUT1] of IC401, the STEP-UP DC-DC CONVERTER consisting of Q402, T401, D405, C422 and the output switching waveform, startsand generates the stepped-up voltage (approx. 11 V during AC adapter drive operation) from the above described VCC voltage. The stepped-up voltage thus generated is sent to pin2 [IN] of the 5 V REG. IC402. As the 5 V REG. IC402 starts up, +5 V is generated by the seriesregulator inside IC402. The +5 V regulated power is output from pin3 [OUT] to pin!£ [VCC] of the D-RAM IC503 as the voltage to drivethe D-RAM IC503.

from IC8016pin PCON

IC401POWER CONTROL

17PCB

TO IC50313pin VCC

VOUT1Q402

D405

T401

VCCVOLTAGE

3.2[V]3

VINVOLTAGE62

29

+

C422

2

3

IN

OUT

IC4025[V] REG.

17

91

1

0

2[V]

11.5[V]

176.4[kHz]

— 45 — — 46 —

DCIN

C412

Q404REG.

R418

D401

D403

R407

C426INM2

RF2

IC401 POWER CONTROL

BATTERY

VIN

L402

R408

Q403

R420

3

4

35VOUT2

C429

Q405

R406

R416

R417

RS

R405 CHGSW

BATM-

DCIN

36

BATM

NT

R518

R567

29

DCIN

MNT

28CHGMNT

IC403CHARGE MONITOR

18CHGON

24 CHGON



R424

R413

R414

23

C431

R427

1

VINVOLTAGE

R422

R423

R425

R426

15

S809BATT

XRCHG

Q406(1/2)

Q406(2/2)

DCINDETECTOR

CHARGECONTROL

ERRORAMP

2

33

30

(Approx.0.35[V])

Q1

17PCB


6

PCON

26

HKEY

KEYMATRIX

When CHARGE button is pressed,this input voltage becomes 1.4[V].

Fig.4-7 Charging circuit block diagram

+-+

+ -

— 47 —

4-4. Charging Circuit


(1) Operation of the system controller IC801 during chargingWhen the DC plug is connected to the DC jack, the VCPU voltage 3 V is generated by the POWER CONTROL IC401, and is sent to thesystem controller IC801 so that it starts up. When the system controller IC801 starts up, the system controller IC801 detects if theDiscman satisfies the following charging conditions or not. After the system controller IC801 recognizes that the following conditionsare satisfied, it outputs the "H" signal from pin@¢ [CHGON]. The charging circuit inside the POWER CONTROL IC401 starts thecharging operation by this "H" signal. At the same time, Q406(1/2) and Q406 (2/2) are turned on by this "H" signal so that the VINvoltage is sent to the CHARGE MONITOR IC403 which starts the monitoring circuit of the charge voltage.

♦ Charging conditions1. The Discman operates on DC (output from AC adapter) n pin@ª [DCINMNT] of system controller IC801: "H"2. The rechargeable battery (BP-DM10) is inserted in the Discman n pin!∞ [XRCHG] of system controller IC801: "L"3. The Discman is in the STOP state n pin6 [PCON] of system controller IC801 outputs the "H" signal.4. The CHARGE button is pressed n Input voltage to pin@§ [HKEY] of the system controller IC801 is 1.4 V.

(2) Operation of POWER CONTROL IC401 when chargingPOWER CONTROL IC401 contains the CHARGE CONTROL block which starts charging when the charging conditions shown inTable 4-2 are satisfied. When IC401 starts charging, IC401 outputs the "H" signal from pin#§ [CHGSW]. This "H" signal turns Q405on. At the same time, IC401 outputs the "H" signal inside IC401 to turn on the N-channel MOS FET Q1. As Q405 is turned on, thevoltage that is obtained by I-V converting the current flowing through the rechargeable battery with external resistors R406, R416 toR417, is input to pin2 [RS] of IC401. IC401 keeps the current that flows through the rechargeable battery constant at all times bycomparing the input voltage at pin2 [RS] with the internal reference voltage (0.35 V) with the ERROR AMP.

(3) Operation when stopping chargingDuring charging, the system controller IC801 detects a –∆ V (minus delta V potential) by monitoring the voltages that are input to pin@•[CHGMNT]. When the system controller IC801 detects a –∆ V, it stops charging by setting pin@¢ [CHGON] to "L". In addition to the–∆ V detection system, the system controller IC801 uses the timer system (timer of approx. two hours) at the same time in order to stopcharging.

Table. 4-2 Charging conditions

During chargingPin 1[DCIN]

H

InputPin !¶[PCB]

HPin !•[CHGON]

H

OutputPin #§[CHGSW]

H

— 48 —

5. APPENDIX: TYPES AND APPLICATIONS OF SECONDARY BATTERIES FORPORTABLE EQUIPMENT (RECHARGEABLE BATTERIES)

5-1. Nickel-Cadmium Rechargeable Battery

The sealed type nickel-cadmium rechargeable battery for consumer use is widely used in compact electronic equipmentbecause it has the following features:

1. Types of Batteries

Sealed type nickel-cadmium rechargeable batteries come in cylindrical, square and button shapes for the various applications.This section describes the cylindrical and square nickel-cadmium rechargeable batteries.

(a) Cylindrical battery (KR)

Fig. 5-1 Structure of cylindrical nickel-cadmium rechargeable battery

Gasket

Safety valve blockInsulation plate

Separator

’plate

‘plate

Cap (‘terminal)

Case (’terminal)

Fig. 5-2 Structure of safety valve

‘terminal

‘terminal

Spring

Exhaust

Exhaust

Spring stay

Spring type

Rubber type

Cap

Cap

Rubber

Rubber valve

The nickel-cadmium rechargeable battery is usually used as the secondary battery for portable equipment. Remarkable improvements inenergy density in recent years together with the increasing diversification and popularity of portable equipment requiring compact rec-hargeable batteries, have led to the development of new rechargeable batteries such as the nickel-hydrogen rechargeable battery andlithium-ion secondary battery, and these batteries are starting to be used in large quantities. This section describes the basic theory of thefollowing three types of rechargeable batteries that are widely used in the Discman and MD WALKMAN.

• Nickel-cadmium rechargeable battery• Nickel-hydrogen rechargeable battery• Lithium-ion secondary battery

• The discharge voltage characteristics are flat.• Boosting charge is possible.• It has a long life.• It withstands over-charging and over-discharging.

• It has a low internal resistance, making possible a high rate discharge (large current discharge).• It has high mechanical strength thanks to its metallic case.• It suffers little deterioration even after a long period of storage.

The cylindrical nickel-cadmium rechargeable battery is the most widely used. Some that have the same dimensions as dry cellbatteries are now also on the market. The many applications include the power supply for portable electronic equipment, electric toolsthat require a fast discharge performance, emergency lights, guidepath lights, etc. The structure of the cylindrical nickel-cadmiumrechargeable battery is shown in Fig. 5-1; a positive electrode and a negative electrode are rolled in a spiral with a separator betweenthe electrodes and are housed in a metal case. The cylindrical nickel-cadmium rechargeable battery has a built-in reset type safetyvalve, so even if the internal pressure of the battery increases due to over-charging with a large current, gas is released through thevalve to prevent the battery from breakage. Figure 5-2 shows the structure of a typical safety valve.

— 49 —

(b) Square battery (GP)

Fig. 5-3 Structure of square nickel-cadmium rechargeable battery

2. Characteristics of Nickel-Cadmium Rechargeable Battery (a) Comparison with dry cell battery

Fig. 5-4 Comparison of discharge characteristics between general-purpose KR battery and dry cell battery

Insulation gasket

Separator

Spacer

’terminal

‘terminal

‘terminal and acts as safety device

Case(’terminal)

High performance dry cell battery

Alkaline-manganese dry cell battery

Discharge : 500 mA Temperature: 20˚c

1.7

1.6

1.5

1.4

1.3

1.2

1.1

1.0

0.9

0.8

0.7

0.6

Dis

char

ge v

olta

ge (

V/c

ell)

KR (KR0.5AA)

0 10 20 30 40 50 60 70 80 90 100

Discharge time (minute)

The square nickel-cadmium rechargeable battery was developed by Japan Storage Battery Co., Ltd. in 1985 for the first time in theworld, and is used in the Sony headphone stereo-cassette tape player. Its shape means that space is not wasted, and so as demand formore compact, thin portable electronic equipment has increased, so too has demand for this battery. Applications include compactAudio & Visual equipment including the headphone stereo-cassette tape player, and communication equipment such as cellularphones. The structure of the battery is shown in Fig. 5-2; strips of positive plate and negative plate are stacked with a separatorbetween them, and are encased in a metallic deep-drawn case. It has a built-in ultra-small safety valve that is just 3.6 mm wide tokeep the battery thin.

A comparison of the discharge characteristics between the size AA nickel-cadmium rechargeable battery and dry cell battery isshown in Fig. 5-4. The discharge voltage of the nickel-cadmium rechargeable battery is characterized by a flat discharge curve anda sharp drop at around the end of the discharge period. The capacity of the nickel-cadmium rechargeable battery is being increased,and AA-size batteries capable of delivering 900 mAh are already in practical use.

— 50 —

(b) Charge characteristics

Fig. 5-5 Standard charge characteristics of general-purpose KR battery

1.7

1.6

1.5

1.4

1.3

1.2

Bat

tery

vol

tage

(V

)

0 2 4 6 8 10 12 14 16

Charge time (h)

Charge current: 0.1 CmA

20˚C 0˚C

45˚C

Am

ount

of d

isch

arge

(%

) 100

90

80

70

60

50 Charge : 15 h at 0.1 CmA (at each temperature)Discharge: Down to 1.0 V with 0.2 CmA (20˚C)

0 10 20 30 40 50 60

Charge temperature (˚C)

Fig. 5-6 Relation between charge temperature and amount of discharge of general-purpose KR battery

Fig. 5-7 Relation between temperature and charge-end voltage of KR battery

1.6

1.5

1.4

1.3

1.2

–10 0 10 20 30 40 50

Bat

tery

vol

tage

(V

)

Temperature (˚C)

Type: KR (general-purpose) (for high temperature trickle charge)

Charge: 15 h at 0.1 CmA

The nickel-cadmium rechargeable battery is charged by the constant current charge method. The charge characteristics of thegeneral-purpose cylindrical (KR) battery are shown in Fig. 5-5. The standard charge takes 14 to 16 hours with the current of 0.1CmA as shown in Fig. 5-5, and requires over-charging. Over-charging is necessary because the charge efficiency decreases asoxygen gas is generated at the end of charging at the nickel hydroxide positive electrode. The relation between the charging temperatureand discharge capacity is shown in Fig. 5-6. The charging efficiency decreases remarkably as the charging temperature rises and asthe charge current decreases. Therefore, an exclusively designed rechargeable battery is used for special applications such as emergencylights, and is charged by a trickle charge. The relation between temperature and the charge-end voltage of the nickel-cadmiumrechargeable battery is shown in Fig. 5-7. The figure shows that the charge-end voltage decreases as the temperature during chargingis higher. This means that the charge current remarkably changes depending upon temperature when the nickel-cadmium rechargeablebattery is charged at a constant voltage. Constant voltage charge must therefore be avoided because it can cause the battery todeteriorate and burnout as an excessive current flows into the battery during charging at a high ambient temperature.

— 51 —

(c) Discharge characteristics

0.2Cm

A

1Cm

A

3Cm

A

5Cm

A

Discharge capacity (%)

Bat

tery

vol

tage

(V

)

1.4

1.3

1.2

1.1

1.0

0.9

0.8

20 40 60 80 100 120

Battery : KR0.7AACharge : 15 h at 0.1 CmATemperature : 20˚C

Fig. 5-8 Discharge characteristics of general-purpose KR battery at various discharge currents

The temperature dependence of the discharge capacity of the KR battery is shown in Fig. 5-9. The discharge capacity decreases at the lowtemperature of 0˚C or below, but discharge is possible over the wide temperature range of -20 to +60˚C.

100

90

80

70

60

50

Am

ount

of d

isch

arge

(%

)

–20 –10 0 10 20 30 40 50

Discharge temperature (˚C)

Charge : 15 h at 0.1 CmA (20˚C)Discharge: Down to 1.0 V with 0.2 CmA (at each temperature)

Fig. 5-9 Relation between discharge temperature and amount of discharge of general-purpose KR battery

The discharge capacity (service capacity*5-1) of the nickel-cadmium rechargeable battery changes depending upon the dischargecurrent and temperature. However, their effects are smaller compared with the dry cell battery and lead rechargeable battery. Thedischarge characteristics of the KR battery at the respective discharge currents are shown in Fig. 5-8. The continuous discharge of 3to 5 CmA is possible as shown in the figure.

♦ Charge-discharge coefficient "C"The value "C" that indicates the hour-rate is frequently used when describing the charge-discharge characteristics. The value "C" iscalled the charge-discharge coefficient. The current of one-C (one-hour rate) (in ampere) is that which is required to discharge a batteryfor one hour, or to charge a battery for one hour. Put simply, when using a battery having a capacity of 10 Ah, discharging the batteryat 10 A is called "a battery discharged at 1C". When the battery is discharged at 1 A, it is called "a battery discharged at 0.1C."

* 5-1: The terminology "discharge capacity" of a battery is sometimes called "service capacity" of a battery.

— 52 —

(d) Capacity storage characteristics

Fig. 5-10 Capacity storage characteristics of general-purpose KR battery

Storage temperature@ @0˚C

20˚C

30˚C

45˚C

Cap

acity

sto

rage

cha

ract

eris

tics

(%)

Storage days (day)Charge : 15 h at 0.1 CmA (20˚C)Discharge: Down to 1.0 V with 0.2 CmA (20˚C)

100

80

60

40

20

030 60 90

(e) Life characteristics

(1) Temperature: The optimum operating conditions of the nickel-cadmium rechargeable battery are normal room temperature.Deterioration of the battery is accelerated if the battery is continuously used under a high temperature exceeding 40˚C.

(2) Depth of discharge: Depth of discharge affects the cycle life. When deep discharge is repeated, the cycle life is shortened.The relation between the depth of discharge and the cycle life of the general-purpose KR battery is shown in Fig. 5-12.

(3) Over-charge and over-discharge: When a nickel-cadmium rechargeable battery is over-charged or over-discharged, theinternal pressure of the battery increases, gas is exhausted from the safety valve, the electrolyte decreases, and hence deteriorationof the battery is accelerated.

100

80 60 40

20

0

Am

ount

of d

isch

arge

(%

)

100 200 300 400 500 600 700

Battery : KR0.7AACharge : 10 h with 0.15 CmADischarge : Down to 1.0 V with 1 CmATemperature: 20˚C

Charge-discharge cycle (times)

10,000

5,000 4,000 3,000

2,000

1,000

500 400 300

Type : General-purpose KRTemperature: 20˚C

0 20 40 60 80 100

Depth of discharge (%)

Cha

rge-

disc

harg

e cy

cle

(tim

es)

Fig. 5-11 Example of cycle life of general-purpose KR battery Fig. 5-12 Relation between depth of discharge and cycle life of general-purpose KR battery

The residual discharge capacity of the KR battery that is measured after full charging and storage at various temperatures, is shown inFig. 5-10. The amount of self-discharge of the nickel-cadmium rechargeable battery is larger than that of the dry cell battery and leadrechargeable battery. The amount of self-discharge increases as the temperature rises.

When describing the life of the nickel-cadmium rechargeable battery, the conditions for measurement are specified by the IECspecifications and the JIS standards. An example of the cycle life characteristics is shown in Fig. 5-11, which shows that the nickel-cadmium rechargeable battery has an excellent life of 1000 cycles or more. However, this is the result under specific conditions, andthe life greatly changes depending upon the operating conditions and other factors. The main causes that affect life are the following.

— 53 —

(f) Boosting charge

Fig. 5-13 Boosting charge system for sealed-type nickel-cadmium rechargeable battery

Battery voltage

Battery temperature

–∆V

Charge time

(1) –∆V (minus delta V) control

Charge time

(2) Temperature detecting control

Battery voltage

Battery temperature

Temperature detection

The cycle life characteristics of the nickel-cadmium rechargeable battery using the boosting charge are shown in Fig. 5-14. Even thesquare nickel-cadmium rechargeable battery has a performance of 500 cycles or more for its charge-discharge characteristics as shownin the figure.

120

100

80

60

40

20

0

Am

ount

of d

isch

arge

(%

)

0 100 200 300 400 500

Charge : Detecting –∆V with 1 CmADischarge : Down to 1.0 V with 1 CmATemperature : 23˚C

Charge-discharge cycle (times)

Fig. 5-14 Example of cycle life of the GP6E type battery using the boosting charge

Several methods of boosting charge are used for nickel–cadmium rechargeable batteries. However, the methods of controlling theboosting charge are classified into two main types: (1) Method of detecting the battery voltage, and (2) Method of detecting the batterytemperature. Examples of actual systems are shown in Fig. 5–13. The –∆V (minus delta V) system that detects the voltage drop afterfully charged is most widely used. In the sealed–type nickel–cadmium rechargeable battery, the battery voltage reaches its peak at thecharge–end, then decreases as the battery temperature rises due to oxygen gas absorption reaction of the negative electrode. Thischaracteristic performance of the battery is detected and used to control charging, which is called the –∆V (minus delta V) system.This system is very reliable; over–charging of batteries is small and mis–operation is unlikely.

— 54 —

(g) Memory effectThe battery voltage of the nickel-cadmium rechargeable battery can decrease in two steps when it is deeply discharged after shallowcharge-discharge is repeated or after trickle charging for many hours. This phenomenon is generally called the memory effect, and caneasily occur when the cut-off voltage of the load equipment is set to 1.1 V/cell or higher. However, this phenomenon is a temporary one,and can be removed by deep discharging once or twice.

— 55 —

5-2. Nickel-Hydrogen Rechargeable Battery

Note 1: Dimensions are the maximum values without insulation tubes.Note 2: HP10 is the product for stereo headphones.

Table 5-1 Comparison of specifications between the square nickel-hydrogen rechargeablebattery "HP series" and conventional square nickel-cadmium rechargeable battery "GP series"

The nickel-hydrogen rechargeable battery (abbreviation: Ni-MH) is a rechargeable battery using nickel oxide as the positive electrodeand a hydrogen occluded alloy as the negative electrode.Square, cylindrical and button shaped nickel-hydrogen rechargeable batterieshaving similar shapes to those of the sealed-type nickel-cadmium rechargeable battery (referred to as "nickel-cadmium rechargeablebattery" hereafter), which are widely used in many types of equipment, are now on the market. The voltage characteristics of the nickel-hydrogen rechargeable battery are similar to those of the nickel-cadmium rechargeable battery. The square nickel-hydrogen rechargeablebattery is outlined below.

1. Outside Appearance and ApplicationsNickel-hydrogen rechargeable batteries are available in both cylindrical and square types like the nickel-cadmium rechargeablebattery, and the outside appearances are also similar. A comparison of various specifications between the square nickel-hydrogenrechargeable battery "HP series" and the conventional square nickel-cadmium rechargeable battery "GP series" is shown in Table5-1. Comparing batteries of the same dimensions, we can see that the volumetric energy density is 38% to 65% higher in the HPseries, and is 15% to 40% better than the high capacity type GPN series. Utilizing these characteristics, the nickel-hydrogenrechargeable battery can be used for many more applications to supply power for various portable equipment such as compactnotebook personal computers and other office automation equipment, as well as in compact communication equipment such ascellular phones.

Width

16.4

16.4

16.4

16.4

16.4

16.4

16.4

16.4

16.2

16.4

16.4

Thickness

5.6

5.6

5.6

7.8

5.6

5.6

7.8

7.8

5.6

5.6

7.8

Name of battery

Nickel-hydrogen

rechargeable

battery

Nickel-cadmium

rechargeable

battery

Nickel-cadmium

rechargeable

battery (high

capacity type)

Model name

HP6

HP9

HP10

HP9CM

GP4E

GP6E

GP6CM

GP9E

GPN4US

GPN5CS

GPN7CM

Nominal voltage

[V]

1.2

1.2

1.2

Rated capacity

[mAh]

560

850

940

850

380

570

580

850

380

480

730

Total height

47.6

66.3

66.3

47.6

47.6

66.3

47.6

66.3

39.6

47.6

47.6

Mass

[g]

17.0

24.0

24.2

23.0

16.5

23.5

22.0

31.5

12.5

15.5

20.5

Volume

[Wh/l]

154

167

185

166

104

112

114

120

127

132

144

Energy densityDimensions [mm]

Mass

[Wh/kg]

39.5

42.5

46.6

44.3

27.6

29.1

31.6

32.4

36.5

37.2

42.7

— 56 —

2. Charge-Discharge Characteristics

Term

inal

vol

tage

(V

)

1.6

1.5

1.4

1.3

1.2

1.1

1.00 40 80 120 160

Amount of charge (% of rated capacity)

Ambient temperature : 20˚C

Charge current 1 CmA0.5CmA0.2CmA

Fig. 5-15 Charge characteristics at the respective charge current of the HP battery

1.7

1.6

1.5

1.4

1.3

1.2

1.1

1.0

Term

inal

vol

tage

(V

)

0 20 40 60 80 100 120


Charge: For 1.2 hours with 1 CmA

Ambient temperature

0˚C

20˚C

40˚C

Fig. 5-16 Charging temperature characteristics of HP battery

Term

inal

vol

tage

(V

)

Charge : For 1.2 hours with 1 CmAAmbient temperature : 20˚C

Discharge current

0 20 40 60 80 100


0.2CmA

1CmA2CmA

0.5CmA

1.5

1.4

1.3

1.2

1.1

1.0

0.9

Fig. 5-17 Discharge characteristics at various discharge currents of HP battery

Term

inal

vol

tage

(V

)

1.4

1.3

1.2

1.1

1.0

0.9

Charge : For 1.2 hours with 1 CmA (20˚C)Discharge : Down to 1.0 V with 1 CmA

Ambient temperature

0 20 40 60 80 100 @120Amount of charge (% of rated capacity)

40˚C

20˚C0˚C

Fig. 5-18 Discharging temperature characteristics of HP battery

The charge characteristics of the square nickel-hydrogen rechargeable battery at various charge currents are shown in Fig. 5-15, andthe temperature characteristics at the charge current of 1 CmA are shown in Fig. 5-16. The behavior of the charge voltage of the squarenickel-hydrogen rechargeable battery is quite similar to that of the nickel-cadmium rechargeable battery. The discharge characteristicsat the respective discharge currents are shown in Fig. 5-17. Comparing the discharge characteristics at the 2 CmA current with thoseat the 0.2 CmA as shown in the figure, the midpoint voltage during discharging decreases about 100 mV, but the discharge capacitydown to 1.0 V decreases only by about 10%. The discharge characteristics at large discharge currents are equivalent to those of thenickel-cadmium rechargeable battery. The temperature characteristics when discharging at 1 CmA are shown in Fig. 5-18, showingthat stable capacity is obtained over the wide temperature range of 0 to +40˚C.

— 57 —

3. Charge-Discharge Cycle Life Characteristics

Charge : –∆V control with 1 CmA (10 mV cell)Discharge : Down to 1.0 V/cell with 1 CmAAmbient temperature: 25˚C

0 100 200 300 400 500

100

80

60

40

20

0

Dis

char

ge c

apac

ity (

%)

Number of charge-discharge cycles (times)

Fig. 5-19 Example of cycle life characteristics of the HP9 battery

4. Capacity Storage Characteristics

Fig. 5-20 Capacity storage characteristics of HP battery

Charge : For 1.2 hours with 1 CmADischarge: Down to 1.0 V/cell with 0.2 CmA

100

80

60

40

20

0

Cap

acity

sto

rage

rat

e (%

)

0 10 20 30

0˚C

20˚C

40˚C

Storage period (days)

The transition of capacity is shown in Fig. 5–19 when the charge–discharge cycle test is performed under the conditions of the 1 CmAcharge controlled by –∆V (10 mV) detection and the discharge limited to 1.0 V with 1 CmA. About 80% or more of the initialcapacity is maintained after 500 cycles as shown in the figure, indicating that it has the superior life characteristics.

The capacity storage characteristics of the square nickel-hydrogen rechargeable battery are shown in Fig. 5-20 when it is charged to120% with 1 CmA at 20˚C, stored at the temperatures of 0˚C, 20˚C and 40˚C, then discharged to 1.0 V/cell at 0.2 CmA at 20˚C. Theresidual capacity after storage for 30 days at 20˚C is about 70% of the initial value, which is almost equivalent to the value of theconventional nickel-cadmium rechargeable battery GP series.

— 58 —

5. Methods of Boosting Charge

Fig. 5-21 Boosting charge method of HP battery

Time

I1 @Charge current

I2

dT/dtdT

dtCell temperature

Terminal voltage

Charge ending timer T

–∆V

Even though the standard charge rate of the nickel–hydrogen rechargeable battery is six hours with 0.2 CmA, the practical trend atpresent is a boosting charge of around one hour. There are two main types of boosting charge control methods for the nickel–hydrogen rechargeable battery: (1) –∆ V method and (2) the method using the temperature rise of the battery.

♦ –∆ V methodThe –∆ V method uses the phenomenon that a battery voltage reaches its peak once, then decreases by the heating that accompaniesthe oxygen gas absorbing reaction of the negative electrode at the charge–end period. The amount of voltage decrease (–∆ V method)is detected. This method ensures a constant voltage level without being affected by the ambient temperature. However, the amountof voltage decrease (–∆ V method) tends to be smaller in the nickel–hydrogen rechargeable battery than that of the nickel–cadmiumrechargeable battery. Therefore, the general practice is to use the –∆ V method as well as another method such as by using thetemperature rise of the battery or by using a timer.

♦ Method using the temperature rise of a battery

The method using the temperature rise of the battery detects the size of temperature rise (∆T) or speed of temperature rise (dT/dt).This method has the advantage that the amount of over–charging is smaller than that of the –∆ V method. However, since it requirestemperature detection using a thermistor or other such element, the method is suitable for assembled batteries but not for a singlebattery that is directly inserted into the battery compartment of an electronic product.

Therefore, ordinary consumer electronic products use both the –∆ V method and the timer method in order to improve the reliabilityof charge control.

The conceptual diagram of the boosting charge method of the square nickel–hydrogen rechargeable battery is shown in Fig. 5–21.The actual values of boosting charge current of I

1 = 1 CmA, trickle charge current of I

2 = 0.03 to 0.05 CmA and –∆ V detection value

= 5 to 10 mV/cell, are considered to be appropriate. The boosting charge ending timer T (60 to 80 minutes) is required in order toprevent batteries from deterioration due to over–charging if the charge ending period is not detected.

— 59 —

(a) High operating voltage

(b) High energy density

5-3. Lithium-Ion Secondary BatteryThe lithium-ion primary battery, with its high capacity and high output voltage in a compact size, is commonly used for memorybackup and as the power supply for small electronic devices. However, with the increasing demand for higher performance and longerbattery life as portable electronic devices have become more sophisticated, lithium-ion secondary batteries are strongly desired foreconomy, effective use of resources and environmental conservation since they can be reused. The lithium-ion secondary battery uses,instead of metallic lithium, carbon materials that are occluded lithium-ion at the negative electrode. Because such batteries are free ofthe problems of metallic lithium, they are expected to be used as the power supply for small electronic devices in future.

1. Features of Lithium-Ion Secondary Battery

(c) Good output characteristicsA current as large as that of the aqueous solution type battery can flow through the external circuit by shortening the distancebetween the electrodes and by increasing the chemical reacting area of electrodes, even though an organic electrolyte of lowconductivity is used. This means that the high capacity lithium-ion secondary battery can power small motors and computerhard disk drives.

(d) Excellent safetyThe lithium-ion secondary battery is far safer than the conventional metallic lithium battery because the lithium exists in theform of ions and not metallic form.

(e) Long cycle lifeThe battery can withstand more than 500 cycles of repeated charging and discharging. Capacity is hardly diminished evenwhen full-charging and full-discharging are repeated, so the cycle life is excellent.

(f) No memory effectThe lithium-ion secondary battery does not show the memory effect that reduces the nominal battery capacity when shallowdischarge and recharge are repeated, which occurs due to the property of nickel-cadmium rechargeable batteries. Therefore,there is no need for the refresh-discharge circuit that discharges the remaining power before starting charging to preventreducing the charging capacity.

(g) Quick chargingCharging can be done at a current larger than that of the battery by using metallic lithium for the negative polarity, and thebattery can be fully charged within one to several hours.

(h) High leakage resistanceThe lithium-ion secondary battery has a high leakage resistance compared with conventional batteries using an alkaline electrolytebecause an organic electrolyte is used that hardly leaks compared with alkaline electrolyte, and an excellent sealing method isused.

Though the operating voltage varies depending upon the type of positive electrode used, the operating voltage is typically as highas 3 to 4 volts, which is equivalent to two or three nickel-cadmium rechargeable battery connected in series. This means that thenumber of cells used in an enclosure can be reduced, and hence the probability of failure is reduced accordingly.

The energy density is 1.5 to 2 times that of the nickel-cadmium rechargeable battery, so batteries can be made compact and light-weight.

— 60 —

Diameter

14

14

16

17

18

21

26

Model

US14500

US14650

US16630

US17670

US18650

US20500

US26650

Nominal voltage [V]

3.6

3.6

3.6

3.6

3.6

3.6

3.6

Rated capacity [mAh]

500

650

850

1200

1350

1300

2700

Approximate dimensions

Height

50

65

63

67

65

51

65

Mass [g]

19

25

29

36

40

40

83

(a) Cylindrical batteryThe cylindrical battery has the structure shown in Fig. 5-22. The battery contains spiral strips of positive and negative electrodesthat are rolled with a separator in between the electrodes and housed in a metal case before sealing. The shape of the lithium-ionsecondary battery looks like a cylindrical nickel-cadmium rechargeable battery, but has special safety features. For example, thebuilt-in PTC element limits the current flow by increasing its resistance to prevent abnormal heating when the external circuit isshorted and a large current flows. Another example is the non-reset type safety valve that operates during abnormality to preventthe battery from explosion due to abnormal increase of inner pressure due to internal shorting or external heating.

2. Types of Batteries

The performance of the typical cylindrical lithium-ion secondary battery is shown in Table 5-2. Applications are portable electronicdevices such as cellular phone, notebook personal computer, mini-disc, video camera power supply, etc.

Fig. 5-22 Structure of cylindrical lithium-ion secondary battery

Table 5-2 Performance of cylindrical lithium-ion secondary battery (manufactured by Sony)

Safety valvePTC element

Positive polarity leadSeparator

Positive plate

Negative plate

Negative polarity lead

Insulation plate

Case

Insulation plate

Gasket

Positive terminal

The lithium-ion secondary battery can be classified into: (1) button-type battery for low current applications such as memory backup,(2) cylindrical-type battery, and (3) square-type battery for cyclic applications. The cylindrical and square batteries are outlinedbelow.

— 61 —

Height

47

48

Model

LP4

LP9

Nominal voltage

[V]

3.6

3.6

Rated capacity

[mAh]

400

800

Approximate dimensions [mm]

Width

22

34

Thickness

6.4

8.3

Mass

[g]

20

40

(b) Square battery

Fig. 5-23 Structure of square lithium-ion secondary battery

Table 5-3 Performance of square lithium-ion secondary battery

Resin cover

Positive terminal

Safety valve

Battery element

Case (negative terminal)

Current shut-off device

Performances of the typical square lithium-ion secondary battery are shown in Table 5-3. The main applications are the portable electronicequipment requiring the compact and thin configuration such as mini-disc, notebook personal computer, etc.

The cylindrical battery does not use space so efficiently, and its thickness cannot be reduced below a certain level. In response to theneed for thinner batteries for compact, slim electronic devices, square batteries were developed. The structure of the square lithium-ion secondary battery is shown in Fig. 5-23; it has almost the same internal structure as that of the cylindrical battery.

— 62 —

3. Battery Characteristics

(1) Charge characteristics

Fig. 5-24 Discharge characteristics of batteries using different materials for negative electrode

The performance of square batteries using graphite carbon materials for their negative electrode are described below.

Fig. 5-25 Charge characteristics of square lithium-ion secondary battery

Voltage

Current

4.5

4.0

3.5

3.0

2.5

Charge : 0.5 CmA, 4.1 VAmbient temperature : 25˚C

1

0.75

0.5

0.25

0

Cha

rge

curr

ent (

Cm

A)

0 2 4 6 8

Charge time (h)

Bat

tery

vol

tage

(V

)

Discharge : 0.2 CmATemperature : 25˚C

Graphite

Low crystalline carbon

Dis

char

ge v

olta

ge (

V) 4.5

4.0

3.5

3.0

2.5

2.00 20 40 60 80 100 120


The cylindrical and square lithium-ion secondary batteries are called cyclic service batteries as they are used in applications inwhich the charge and discharge cycle is frequently repeated. The cylindrical and square lithium-ion secondary batteries have almostthe same battery characteristics. However, the charge/discharge characteristics of the two are slightly different in the type of carbonmaterial that is used for the negative electrode. Figure 5-24 shows difference in the discharge characteristics of batteries having thedifferent types of carbon material for the negative electrode. The graphite negative electrode means carbon materials having highcrystallization such as natural graphite and artificial graphite. This battery is characterized by very flat discharge voltage characteristics.In Fig. 5-24, the low crystalline carbon negative electrode indicates the use of carbon materials having low crystallization. Becausethe discharge voltage changes linearly in proportion to the amount of discharge, the residual power of the battery capacity can easilybe displayed.

The charge characteristics are shown in Fig. 5-25. Because the characteristics of lithium-ion secondary batteries severely deteriorateand safety is impaired if they are charged at higher than the rated voltage, a charging device offering both constant current andconstant voltage charging methods with a restricted, specified maximum voltage is required. In the constant current chargingzone, the battery voltage increases as the battery is charged. When the battery voltage reaches the set voltage, the charging methodis switched to the constant voltage charging. When the battery is charged by the constant voltage method, the charging currentgradually decreases until the charging is complete. Some types of batteries can be charged quickly in one or two hours.

— 63 —

(2) Discharge characteristicsThe discharge characteristics of various discharge currents are shown in Fig. 5-26. The lithium-ion secondary battery can carry alarge discharge current of up to 2 CmA with a reasonably flat discharge voltage as shown in the figure.

Fig. 5-26 Discharge characteristics of the square lithium-ion battery at various discharge currents

Fig. 5-27 Discharge characteristics of the square lithium-ion battery at different temperatures

(3) Temperature characteristicsThe discharge characteristics at various temperatures with 0.2 CmA are shown in Fig. 5-27. The lithium-ion secondary battery canprovide a discharge capacity of 90% or more at the low temperature of 0˚C as shown in the figure.

Bat

tery

vol

tage

(V

)

5

4

3

2

1

0

Charge : Constant current and constant voltage 0.5 CmA, 4.10 V x 5 h (25˚C)Temperature : 25˚C

1 CmA

0 20 40 60 80 100 120


0.2CmA

0.5CmA

2 CmA

5

4

3

2

1

0

Bat

tery

vol

tage

(V

)

0 20 40 60 80 100 120


0˚C 25˚C 45˚C

Charge : Constant current and constant voltage 0.5 CmA, 4.10 V x 5 h (25˚C)Discharge @ : 0.2 CmA

— 64 —

(4) Storage characteristics

Fig. 5-28 Capacity storage characteristics of the square lithium-ion secondary battery

(5) Cycle life characteristics

Fig. 5-29 Cycle life characteristics of the square lithium-ion secondary battery

120

100

80

60

40

20

00 10 20 30

Duration of storage (days)

Charge : Constant current and constant voltage 0.5 CmA, 4.10 V x 5 h (25˚C)Discharge : 0.2 CmA. Down to 2.75 V/cell

Cap

acity

per

cent

age

(%) 0˚C

25˚C

45˚C

120

100

80

60

40

20

0

Cap

acity

per

cent

age

(%)

Charge : Constant current and constant voltage 0.5 CmA, 4.10 V x 5 h (25˚C)Discharge : 0.5 CmA. Down to 2.75 V/cellTemperature : 25˚C

0 100 200 300 400 500

Number of cycles (times)

The storage characteristics of the lithium-ion secondary battery are shown in Fig. 5-28. The capacity decrease during the initial periodis somewhat large as shown in the figure. However, the rate of capacity decrease tends to become small with the elapse of storagedays. The storage characteristics of the lithium-ion secondary battery are superior to those of the nickel-cadmium rechargeable batteryand the nickel hydrogen rechargeable battery.

The cycle life characteristics of the lithium-ion secondary battery are shown in Fig. 5-29. The lithium-ion secondary battery deliversa charge/discharge cyclic performance of 500 cycles or more as shown in the figure.

— 65 —

4. Charge Method

5. Precautions When Using Lithium-Ion Secondary Batteries

The lithium-ion secondary batteries must be charged using the charger recommended by the battery manufacturer or with the chargingmethod specified by the battery manufacturer within the specified temperature range (+5 to +45˚C). If the specified charging conditionsare not observed, the batteries will not deliver their full performance and their life may be shortened, or abnormal heating or evenexplosion or fire could occur. The lithium-ion secondary battery has a large energy itself. The components of the battery such aselectrolyte and negative electrode are made of inflammable material, and so an excessive charging voltage and excessive chargingcurrent severely stress the batteries and can cause explosion or fire. If the lithium-ion secondary batteries are charged with anothertype of charger that does not satisfy the specified charging conditions, the batteries may not be fully charged, the metallic lithium maybe precipitated and cause safety problems, or the electrolyte may cause electrolysis and generate gas so that the safety valve operates.Utmost care is required if the batteries are not to become inoperable.

The cylindrical and square lithium-ion secondary batteries are charged using the constant current and constant voltage charge method.In this method, a battery is charged up to a set voltage (4.1 V or 4.2 V, for example) at a constant current (constant current of 0.5 CmAper 2 hours). When the battery voltage reaches the set voltage, charging is continued at a constant voltage. When the charge methodis switched to the constant voltage charging, the charging current gradually decreases and becomes almost zero when the battery isfully charged. Thus, the charging operation ends automatically, and over-charging of a battery is prevented.

Lithium-ion secondary batteries have a high energy density and are expected to be used in a wide range applications because of theirsuperior characteristics. However, improper handling can cause danger so much more handling care is needed than with conventionalsecondary batteries.

(a) Prevent batteries from shorting

(b) Do not disassemble the batteries and do not deform the battery case

(c) Do not throw into fire, do not place in abnormal heat, and do not heat them

(d) Do no solder directly to the batteries

If the positive and negative terminals are shorted, the battery will heat up and could cause an explosion and fire. Batteries may beshorted accidentally if they are transported together with metallic necklaces or hair-pins, for example. Shorting between the batteryterminals must be prevented by storing the batteries in special cases or soft cases when transporting them.

The organic solvents that constitute the organic electrolyte are inflammable and have an irritant smell. The lithium chloride solute isstrongly corrosive against metals so leakage of the electrolyte must be avoided. Because the negative electrode generates hydrogenand causes heating or even fire when reacted with water, disassembling that exposes the inside of the battery or deformation of thebattery enclosure is dangerous. Do not damage the batteries such as striking a nail into them, hitting the batteries with a hammer orcrushing them.

The batteries are housed in a sealed structure. If they are placed in abnormal heat or thrown into a fire, inflammable gas or vapor willbe ejected from the safety valve, and hence the enclosure may break, the battery ignite, or some other danger may occur.

Doing so will heat the batteries to a dangerously high temperature.

— 66 —

(e) Prevent the batteries from coming into contact with water or getting wet

(f) Do not connect the batteries in reverse polarity

(g) Do not discharge at a current larger than the specified value

(h) Do not charge at a current larger than the specified value

(i) Do not over-charge batteries

(j) Do not over-discharge

(k) Do not disassemble the battery pack or modify it

Be careful not to let the batteries get wet with water or sea water. The lithium-ion secondary batteries have a high electromotive power,and when placed in water, electric current continues to flow, electrolyzing the surrounding water and hence corroding the batteryenclosure and terminals. Such battery damage shortens the life of the battery.

As with other types of battery, connecting batteries in reverse polarity may damage equipment during operation, damage the battery,or cause a fire during charging.

If batteries are discharged at a current larger than the specified value, the batteries will become abnormally hot and deteriorateirrecoverably, or the batteries may become inoperable if the safety valve is triggered.

If batteries are charged at a current larger than the specified value, the batteries will become abnormally hot and battery life will beadversely affected. At the same time, electrolyte will be dissolved and generate gas or metal lithium, causing internal shorting.Therefore, be sure to use the special charger to charge the batteries.

If batteries are charged exceeding the specified upper limit voltage, electrolyte will be dissolved and generate gas or metal lithiumwill be generated that causes internal shorting. Over-charging will remarkably degrade the battery characteristics or make batteriesinoperable if the safety valve is triggered. If batteries are severely over-charged, the batteries may even explode or ignite.

If batteries are over-discharged exceeding the charge end voltage, the electrodes may deteriorate irrecoverably, or electrolyte may bedissolved. This can cause the collector or internal leads to melt, adversely affecting the performance and causing poor contact.

The battery pack has a built-in protection circuit to prevent danger. If the protection circuit is disconnected or damaged whendisassembled or modified, it will not function in case of emergency, and so heating and damage to the batteries may occur. Neverdisassemble or modify the batteries.

— 68 —

Sony CorporationPersonal A&V Products Company

98H1630-1DPrinted in Japan ©1998.8

Published by Quality Engineering Dept.(Shibaura)

9-924-949-31

discman power supply circuit operation manual

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