ixan0013.pdf

IXYS Corporation; 3540 Bassett Street; Santa Clara, CA 95054; Tel: 408-982-0700; Fax: 408-496-0670IXYS Semiconductor GmbH; Edisonstr. 15; D-68623; Lampertheim, Germany; Tel: +49-6206-503-0; Fax: +49-6206-503627

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APPLICATION NOTE: IXAN0013

CAPACITOR CHARGE/DISCHARGE CIRCUITS, UTILIZING HIGH VOLTAGE

IGBTS AND ZCS RESONANT MODE TECHNIQUES

By:ABHIJIT D.PATHAK

© 2000 IXYS Corporation

There are many applications which requirepulse power. The needed burst of energy is de-rived by rapidly discharging a previously chargedcapacitor. As the energy stored in a capacitor isequal to 1/2CV2, higher voltage gives consider-ably greater pulse power.

There are many applications of pulse power,such as pulse lasers, which may be used for cut-ting or welding or flashlamps, which may be usedto generate flashes of high intensity light. All theseand many more applications require bursts ofenergy that can be derived from fast dischargeof a previously charged capacitor. The applica-tions and need for pulse power has seen expo-nential growth in the last decade and is likely tocontinue.

The capacitors used in these types of equip-ments are high voltage energy storage capaci-tors that need to be carefully charged by a spe-cially designed “Capacitor-Charging Power Sup-ply” CCPS. Fig(1) depicts charge and dischargecycle of the capacitor (or banks of capacitors inSeries/parallel, depending on the energy requiredand Voltage rating of Capacitors), in which onecan easily see the soft and slow charging cycleand the abrupt discharge. Notice also the tricklecharge or refresh mode, which immediately fol-lows the charge mode.

In order that these capacitors be charged in theshortest possible time, without causing unduestresses on semiconductors or wound compo-nents, it is advisable to use high frequency reso-nant mode ZCS inverter operating between 20to 30 KHz. IXYS Corporation’s BIMOSFETs canperform creditably as switches for this resonantmode inverter.The chosen devices: IXBH40N140, IXBH40N160 or the new IXBF40N140 andIXBF40N160 in isolated i4 -PAC, depending onMains Voltage. For calculating the inductance of

the resonating choke, leakage inductance of thestep-up transformer (as reflected on the primaryside) has to be taken into account.

The incoming mains are first rectified by a 3-phase rectifier bridge, e.g. VUO 36-14N08,assuming mains input voltage is 440VAC, 50Hz/60 Hz. If 550 VAC, 3 phase is avail-able, one can use VUO 36-16N08 and likewisefor 575 VAC, choose VUO 36-18N08.The cur-rent rating also depends on the number of ca-pacitors connected in parallel and, therefore, theirtotal capacitance. The rectified power is filteredby a D.C.Choke, made up of four “C” cores(manufactured from annealed 0.23mm strips ofCRGO grade silicon iron ), arranged in such away that with the specified air gap, and copperstrip wound on a bobbin, it gives just adequateinductance at the operating D.C. current withoutsaturating.

An electrolytic capacitor filters the D.C. bus.Please note the fast acting fuses placed strate-gically to protect semiconductors. A shunt placedjust between the common return path of the in-verter and 3-phase bridge rectifier can enable oneto pick the voltage off the shunt and, after properconditioning, use it to shut off the inverter in caseof overload or short circuit. Likewise, one can alsoput Current transformers on each incoming mainsand use that to monitor the load and also to use itto trip the shunt operated circuit breaker in caseof malfunction or overload. Notice the line filterinductors (LF) placed in series with each phase.This is generally constructed out of E+I cores (with identical three limbs, and three identical bob-bins) wound with required gauge polyester insu-lated copper winding wire, and a required air gapbetween stack of “E” and stack of “I”. The geom-etry, number of turns and air gap determine theinductance and saturation flux density of this filterinductor, whose purpose it is to reduce the di/dt


2


and, in conjunction with three CF(filter capacitors),to filter out the unwanted noise, spikes frommains.

As the resonant inverter operates at a frequencyin the range of 20 to 30 khz, the step-up trans-former is quite small. The inverter can be oper-ated with variable frequency and a predefined dutycycle for ON and OFF, so as to satisfy the ca-pacitor charging requirement.

Please note the high speed bridge rectifier,VBE 20-20N01, made up of FRED Diodes andhaving PIV of 2000 Volts, just right for chargingThe series parallel combination of four capaci-tors to 2000 VDC. A carefully designed high fre-quency choke controls rate of in-rush current intothe capacitors and also filters the rectified power.Ifstill higher D.C.Bus Voltage upto 3500VDC oreven 3750 VDC is desired, one can use two VBE20-20NO1 in series.

Two High Voltage IGBTs IXLF19N250A orIXEL40N400 operating in parallel, to match thecurrent requirements of the pulse load, can handlethe capacitor’s abrupt discharge functions. Adriver circuit that can turn ON or OFF this HighVoltage IGBT is shown in Fig.(9). Notice that anisolation transformer is used to generate isolatedVcc for this driver circuit. This circuit can easilydrive two of these IXLF19N250A or IXEL40N400connected in parallel.HIGH FEQUENCY TRANSFORMER, RESO-NANT INDUCTOR AND HIGH FREQUENCYFILTER CHOKE

It is proposed to use Amorphous Metal Coresfor building the above three wound components.Several advantages ensue all at once, whenAmorphous Metal Cores are chosen, instead ofFerrite, Powdered iron or CRGO cores. Theseare listed below, as benefits over conventionalcores:

1.Temperature rise: Reduced2. Energy Efficiency: Increased3.Compactness : Increased4. Reliability: Increased

5.Application Freq. Range:Higher6.Cost : ReducedThe above advantages accrue, because of cer-

tain intrinsic properties of Amorphous Materials,which offer lower core losses, even while operat-ing at relatively higher flux densities, exhibitingexcellent permeability and high frequency perfor-mance. Ferrites are brittle, requiring extreme carein handling. Besides ferrites can’t be operated athigh flux densities. Unlike Ferrites, AmorphousMetal Cores are quite rugged and require no spe-cial care. They are available as “Torroids” and/or“C” Cores in various shapes & sizes to meet par-ticular requirement of power.

Classical design procedures can be followedfor designing resonant inductor, high frequencytransformer and high frequency filter inductor.THE CONTROL CIRCUIT

D.C. to A.C. Inverters operating at High Volt-age and High Frequency tend to gain significantadvantages when using resonant mode and zerocurrent switching technique due to reducedswitching losses.

The Control Circuit consists of UC 3865, reso-nant mode controller in ZCS ( Zero CurrentSwitched) mode. This circuit is shown in Fig.(7).

Rmin together with Rrange and Cvco determinethe operating frequency. For the application ofcapacitor charging, using BIMOSFETs , one canchoose frequency in the range of 20 to 30 khz,wherein optimization is obtainable. Rmin sets theminimum frequency, while Rrange in conjunctionwith P5 can set the operating frequency. Outputvoltage is sensed using Rs and Ps as shown inFig.(2).This sensed voltage can range from 0Volts to 2 Volts, that can be fed into the Op AmpU1 in Fig.(7) . U1, U2 and U3 form a linear Ampli-fier with opo-isolation using, LOC110 or LOC111or LOC 112 from Clare,inc(An IXYS Company).Using this arrangement 0-2 Volts feedbacksensed from across the Charged Capacitorbanks, is converted into isolated 0-8 VDC forfeeding into UC3865 through lead/lag network.Ps in Fig.(2) can help decide level of this feed-


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back (proportional value); R5, P3, and C5 inFig.(7) determine lead (or velocity or derivative)compensation, while P4, C2 and R6 determinelevel of lag (or Integral) compensation. Optimumadjustments can yield stable value of output volt-age, within preset value(with minimum error) andwith desired level of stability. Please note that thecircuit has soft start feature, which comes into ef-fect, every time inverter is restarted.

Resonant current in the inverter bridge issensed by Hall effect transducer which is insertedin the resonant primary loop. For rectification, useeither Schottky Diodes or FREDs (Fast Recov-ery Epitaxial Diodes, forming a bridge rectifier).After filtering, it is sensed as a voltage acrossR3 . This is fed into “zero” input directly. R1 andP1 help adjust the fault level of this current beforefeeding this signal into “Fault” pin of UC3865. Hinand Lin are the outputs of this ZCS resonant modecontroller. Hin and Lin are fed into the Driver Cir-cuit, which, in-turn, can drive four BIMOSFETs inthe “H” Bridge forming high frequency inverter.BIMOSFET DRIVER CIRCUITS

BIMOSFETs are new improved devices, whichfulfil the special requirements of high voltageMOSFETs having lower conduction losses. Untilthe arrival of IXYS CORPORATION’s 1600VBIMOSFETs, one had to connect two (say, 800V)MOSFETs in series to get a high voltageMOSFET, with its attendant driving complexity.The available IGBTs were too slow for some ap-plications. The technical specifications of the en-tire range of BIMOSFETs are available from IXYSCORPORATION.

Their internal construction is different from bothMOSFETs and IGBTs; however, they can bedriven easily, using any MOSFET/IGBT driver.IXBD4410 AND IXBD4411 HALF BRIDGEMOSFET/IGBT DRIVER CHIPSET

This chipset is best suited to applications in HalfBridge, Full Bridge and 3 Phase Bridge topolo-gies. Here the IXBD4410 is wired as a full-fea-tured Low-Side Driver, while IXBD4411 is wired

as a full-featured High-Side Driver. Together, theymake up a stand alone Driver System for Phaseleg of any of the above mentioned Bridge Con-figurations. The suggested wiring diagram isshown in Fig.(8). Likewise, the wiring diagram isto be repeated for each phase leg and hence oneneeds two such cards for “H” Bridge and threesuch cards for 3-Phase Bridge.

As can be seen in this schematic, to obtain gal-vanic isolation, it uses one ferrite core transformerfor sending drive signals to IXBD4411 and an-other ferrite core transformer for receiving faultand status signals from IXBD4411. T1 representsboth these transformers housed in one IC typepackage. To avoid saturation, capacitors areplaced in series with each primary winding towhich AC (time-varying signals) are transmitted.1200 Volts of isolation barrier is built in.

Both IXBD4410 and IXBD4411 are feature-richDrivers. These include:1. Undervoltage and overvoltage lockout protec-tion for Vcc;2. dV/dt immunity of greater than ± 50 V/ns;3. Galvanic isolation of 1200 Volts (or greater)between low side and high side;4. On-chip negative gate-drive supply to ensureMOSFET/IGBT turn-off even in electrically noisyenvironment;5. 5 volt logic compatible HCMOS inputs with hys-teresis;6. 20ns rise and fall times with 1000 pF load and100 ns rise and fall times with 10000 pF load;7. 100 ns of propagation delay;8. 2 Ampere peak output Drive Capability;9. Automatic shutdown of output in response toovercurrent and/or short-circuit;10.Protection against cross conduction betweenupper and lower MOSFET/IGBT;11.Logic compatible fault indication from both lowand high-side drivers.

H-BRIDGE DRIVER CIRCUIT, USINGBOOTSTRAPPING TECHNIQUE, WITHOUTOPTO-ISOLATION


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Fig(3) shows this circuit with all the necessarydetails required to build it for driving BIMOSFETs.It is necessary first to understand the driving re-quirements for BIMOSFETs, connected in “H”Bridge configuration. Note that the primary re-quirement of any driver is to be able to chargethe gate-source or gate-emitter capacitance, withrequired speed. Another requirement is to haveminimum propagation delay, guaranteeing veryquick response time between occurence of over-load /short circuit and switching off of theBIMOSFETs. In fact, the Control Circuit describedabove will just do that. A TWO-INPUT-AND gatecontinuously monitors gate signals Hin and Lin(for upper and lower BIMOSFETs in the “H”Bridge), and in the unexpected event of simulta-neous occurence of the two, the AND gate gen-erates a LOGIC HIGH and the Driver IC will stopthe output for that much duration. This way, cata-strophic punch through between upper and lowerBIMOSFETs can never ever occur.

“H” Bridge configuration has another unique re-quirement, that is the upper BIMOSFET ‘s emit-ter is not at the ground potential, but is floating,making it necessary to either employbootstrapping technique or use galvanic isolation(using opto-coupler or transformer) to drive theupper BIMOSFETs. Bootstrapping technique isused in Fig(3). It is always wise to use negativebias on the gate of non-conducting BIMOSFETin the “H” Bridge. Fig(3) depicts how -ve bias isgenerated for upper and lower BIMOSFETs.Please note that for the Driver IC chosen, onecan’t exceed a total power supply voltage of 20volts; hence we have chosen -3.9 volts. Note thata low current sensitive zener with sharp knee and1% tolerance should be chosen.

In order to protect the gate-emitter junction ofthe BIMOSFETs, two 18V Zeners, connectedback-to-back are put across the junction. Hereagain choose low current sensitive zeners withsharp knee and 1% tolerance of Vz. Rb providesa bleed off path for stray charge, that might haveaccumulated between gate and emitter junctionof the BIMOSFETs, to facilitate faster switch-off.

Rg sits in between the output pin of Driver ICand gate of BIMOSFET. Selection of proper valueof this resistor depends on various factors; pri-mary among them is speed, with which to turn onthe BIMOSFET. Another effect is that of dv/dt (ofthe Collector-to-Emitter voltage, during switching),which could, by charging the Collector-Gate-Ca-pacitance, force a large current out of the gate,which may damage the output stage of the DriverIC. Presence of sufficient value resistance, be-tween output of the Driver IC and Gate ofBIMOSFET, prevents this from happening. It isappropriate at this juncture to talk of the impor-tance of properly selected snubber circuit, con-sisting of non-inductive low value power resistorconnected in series with optimally chosenprolypropelene capacitor.This snubber is highlyrecommended and by using it, one is loweringthe dependence of Rg on dv/dt related compul-sions. If by any chance one is trying to connecttwo BIMOSFETs in parallel to increase currentcarrying capacity, then presence of Rg in serieswith gate of each BIMOSFET helps in ensuringsimultaneous Turn-On and Turn-Off of the twoBIMOSFETs connected in parallel. An optimalvalue of Rg ,say, 22 ohms can thus be chosen.

A fast switching diode (such as 1N4148) con-nected inversely across Rg helps very fast turn-off of the BIMOSFETs. If necessary, a low valueresistor can be connected in series with thisswitching diode to obtain soft turn-off.

For most applications, Driver ICs, which haveD.C. Bus specification of 600 VDC will work.

For the sake of completeness, Fig(4), depictssuggested circuit diagram for BIMOSFETs con-nected in 3 phase bridge configuration. All theabove comments apply to this Driver circuit aswell.MOSFET/ BIMOSFET/ IGBT DRIVER CIR-CUIT WITH OPTO-ISOLATION FOR “H”BRIDGE INVERTER

Fig(5) depicts complete circuit utilizing opto-isolators, identically for each switching device inthe “H” Bridge. Needless to say, the lowerswitches in the bridge actually do not require opto-


5


isolation, as they are referenced to commonground. The logic behind making identical chainsof opto-isolators and push-pull matched transis-tor pairs is to guarantee same propagation de-lays for the gate signals for all switches in the “H”Bridge, so when they arrive at the gate of theswitches, they bear the same phase relationships,as when they were fed into the driver circuit.

Note that the input signals are individually fedinto darlington transistor arrays so as to boosttheir current capacity. These, in turn, are fed intohigh speed opto-couplers. The output of the opto-coupler is fed into matched transistor pairs ofPNP & NPN through a resistor. Note the elabo-rate bypassing of isolated power supplies, nearthe transistor pairs with high quality capacitors(having minimum ESR & ESL).

For both upper BIMOSFETs in the “H” Bridge,isolated power supplies are used to power thePNP-NPN matched transistor pairs. A completepower supply circuit is shown as one of the waysof generating isolated + & - 15 VDC power sup-plies. Alternatively, D.C. to D.C. converter (or A.C.to D.C. PFC switcher) can be used with multipleisolated + & - 15 VDC supplies.

Rb helps provide a bleed of path for any accu-mulated stray charge on gate-emitter capacitanceof the BIMOSFETs, while the 18 V zeners con-nected back to back ensures that the gate neverever receives any signal higher than 18.7 volts ofeither polarity. Note the simple technique used toprovide designer with independent choices forselecting Rg ON and Rg off. This enables one todesign in the turn-on and turn-off speed of theBIMOSFETs. A properly designed snubber net-work of Rc and Cc across each BIMOSFET en-sures that BIMOSFETs do not turn- On inadvert-ently due to dv/dt . For the sake of completeness,Fig(6) depicts similar circuit for drivingBIMOSFETs in a 3 phase bridge inverter configu-ration.PULSED LOAD

Once the energy storage capacitor bank is fullycharged, the pulsed load can be turned on by oneor more High Voltage IGBTs.( IXYS Corporation’s

IXLF19N250A has a VCES rating of 2500 Voltsand Max. IC rating of 32 Amps, while IXEL40N400has Max Ic rating of 40 Amps and VCES rating of4000 V) depending on the load current. This canbe controlled by sensing the voltage across theseries-parallel bank of four capacitors and turn-ing on S5 and S6 simultaneously. A series-paral-lel combination of four CL along with stabilizingpower resistors is what is shown in Fig.(2). Thiskind of an arrangement allows use of,say, four1000 Volts rated capacitors to be used on a 2000Volts charging circuit and thus get four times theenergy output from the same capacitors. As soonas CL is discharged the control circuit, starts itssoft charging cycle, with designed-in chargingtime. Note that IXLF19N250A can easily handle2000 VDC as final voltage on the capacitor bankand in a transient voltage free environment, thiscan be extended upto,say,2200 or even 2300VDC, which will give greater energy storage ca-pability. For still higher Voltage, IXEL40N400 isrecommended. This very high Voltage IGBT fromIXYS is rated at Vces=4000 Volts and Ic=40Amps. Here the Bus Voltage can go up to 3500V or even 3750 V.

If a higher D.C.Bus voltage is available, highfrequency high voltage transformer can be doneaway with and the CL can be directly charged bythe same circuits described above.

The versatility of this system lies in its ability tocharge a variety of energy storage capacitors formany different types of pulsed loads. The reso-nant frequency of the Full Bridge Inverter is deter-mined by value of total inductance and capaci-tance (both distributed and lumped) in series. Thecapacitance of the energy storage capacitor,being charged, is reflected to primary by multi-plying its value by square of the transformer turnsratio(i.e.Crefl= Cx(Ns/Np)2 By changing the rateof charging, one can keep the same currentthrough resonant circuit, for some variations incapacitance values. As this high value capaci-tance, when reflected to primary, is effectivelyconnected in series with Cr and Lr, the net serieseffective value of capacitance, which determines


6


the resonant frequency, is nearly same as Cr. Thisis, because when one very small value capacitorand one very large value capacitor are connectedin series, the net effective value is approximatelyequal to the smallest value(1/Ceff=1/Cr+1/Creflwhere Ceff stands for effective value of net ca-pacitance which determines resonant frequency,Crefl=value of energy storage capacitance re-flected to primary, Cr=lumped value of capacitorconnected in series with Lr). This is the virtue ofthe chosen series resonant inverter, which unlikeparallel inverter, operates at the same frequency,even though different value energy storage ca-pacitors are being charged.

If capacity doubling is called for, twoBIMOSFETs can be paralalled in the “H”Bridge.Likewise more IXLF19N250A orIXEL40N400 can be paralleled in series with thepulsed load. Vce(sat) and Vf of BIMOSFET have apositive temperature co-efficient. This makes itvery easy for them to be paralleled. Even the for-ward voltage drop of the Anti-Parallel diode, hav-ing same current rating as the BIMOSFET, has apositive temp. co-efficient, enabling it also toshare currents equally, when connected in paral-lel.

Similarly IXLF19N250A or IXEL40N400 alsohave positive temp.co-efficient and hence theywill tend to share discharge current equallyamongst themselves.

It is, of course, understood that similar doublingof capacity will entail choosing appropriately ratedhigher capacity 3-phase rectifier from a numberof available units from IXYS CORPORATION. Onecan then choose fuses and MCBs (with proper i2trating) and bigger filters. For output single phasehigh speed rectifier, a full range of FRED diodesare available from IXYS CORPORATION. A fullbridge rectifier can easily be constructed, usingthese FRED diodes.

DISCLAIMER:Although information furnished herein is believedto be accurate and reliable, Author or IXYS Cor-poration assume no responsibility for its use; norfor any infringement of patents or other rights ofthird parties which may result from its use.


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IND

IP IC2

Rb

-3.9

V-V

cc

C3

D8

Ec

16 P

IN

9

DIP

13IC

1

IC4

Lin

Hin

c

2

a1

C1

1231110

Vcc+

15V

96

D1

-3.9

V-V

cc

Vcc+

15V

D2

2135

D4

RgG

cD7

R1

Rb

7C

2

Rg

D6

Ea

D5

D3

Ga

13

12 13

Lin

d

Hin

bC4

IC4

12111110

Vcc+

15V

Rb

Ed

-Vcc

-3.9

V

C6

D16

(FO

R R

EFER

ENCE

)

6D

9

Gb Eb G

d-Vcc

-3.9

V

2135

D12

RgD1

5

Vcc+

15V

R1D

10

C57

Rg

Rb

D14D1

3

D11

EcGc

EaGa

EdGd

EbGb

H.V.


10


Fig.

(4) 3

Brid

ge D

river

circ

uit u

sing

Boo

tstr

appi

ng te

chni

ques

, with

out O

pto-

isol

atio

n ø

IC1,

IC2,

IC3=

IX2R

11P7

Fo

r DC

Bus

Vol

tage

s up

to 6

00 V

DC

IC4=

CD

4081

Tw

o in

put A

ND

gat

eD

1,D

9,D

17=D

SEP

8-12

AD

3,D

4,D

11,D

12,D

19,D

20=1

N58

22D

5,D

6,D

7,D

8,D

13,D

14,D

15,D

16,D

21,D

22,D

23,D

24=1

8V,4

00m

wSe

nsiti

ve Z

ener

with

sha

rp K

nee

D2,

D10

,D18

=3.9

V,40

0mw

sen

sitiv

e Ze

ner d

iode

s w

ith s

harp

kne

eC

1,C

4,C

7=47

MFD

,25V

DC

Tan

talu

m C

apac

itors

C2,

C3,

C5,

C6,

C8,

C9=

0.1M

FD,1

000

volts

pol

yest

er o

r Pol

ypro

pyle

ne C

apac

itors

R1=

33K

, 2 W

(Val

ue a

nd w

atta

ge d

epen

ds o

n D

.C. B

us v

olta

ge; v

alue

cal

cula

ted

by c

onsi

derin

g Ze

ner c

urre

nt)

Rb=

10k,

1/4w

Rg=

4.7

Ohm

s to

33

Ohm

s (D

epen

ds o

n M

OSF

ET /

IGB

T be

ing

driv

en in

det

erm

ines

turn

on

spee

d of

dev

ice)

Rb

-3.9

V-V

cc

C3

D8

Ec

9

Lin

Hin

DIP

13IC

1

c

2

a1

IC4

12311

C1

10

16 P

IN

Vcc

+15V

96

D1

Vcc

+15V

D4

21

Rg

D2

35R

1

Gc

D7

-3.9

V-V

cc

Rb

Rg

7C

2D

3

Ea

D6D5

Ga

DIP

13IC

2

10 11 12Li

nd

Hin

b

IC4

1312

11

C4

16 P

IN

Vcc

+15V

Rb

Rb

Sb Sd

3 In

verte

r Brid

geø(FO

R R

EFER

ENC

E)

Sc

Ec

Gc

EdGd

-Vcc

-3.9

V

C6

D16

Ed

Sa

Ea

Ga

EbGb

Sf

EfGf

Se

EeGe

H.V

.-3.9

V-V

cc

C9

D24

Ef

96

D9

D12

Vcc

+15V

21

Rg

35D

10

D15

Gd

R1

-3.9

V-V

cc

D11

Rb

Rg

C5

7

D13

D14

Eb

Gb

DIP

13IC

3

IC4

Lin

Hin

f

9

e8

C7

121011

16 P

IN

10

Vcc

+15V

D17

6

-3.9

V-V

cc

D18 V

cc+1

5V

Rg

2135

D20

D23

Gf

R1

Rb

7C

8

D22

Rg

Ee

D21

D19

Ge


11


Fig.

(5) M

OSF

ET/B

I-MO

SFET

/IGB

T D

river

Circ

uit w

ith O

pto-

isol

atio

n fo

r `H

' B

ridge

Inve

rter

d

100

100

43

GN

D3

+

U4

C8

56

inpu

t

inpu

td

1 2

+ 8 7

+

GN

D3

GN

D3

C7C6

c

4321

U3

567

GN

D3

8+

C5

Rs

Rs

(Isol

ated

)-1

5VRg

OFF

Q8

D8

D7

Ed

Rb

(FO

R R

EFE

RE

NC

E O

NLY

)

Ec

H-B

RID

GE

-15V

(Isol

ated

)

Rg

ON

(Isol

ated

)

B

ECQ

7d

(Isol

ated

)-1

5V

+15V

Gd

Ec

Rg

OFF

Rg

ON

Q6

E

D6

D5

(Isol

ated

)+1

5V

B

Q5

C

c

Rb

Gc

c

Gc

Ea

Sc

Ga

Sa

Rs

Rs

Cs

Cs

Sd

Cs

Cs

H.V

.

Sb

+-

GN

D3

C26

2

7915

3C

22

-+C

25

1

-

+-D

21

100

100

inpu

t

4

b

321

+G

ND

2

U2

C4

5678

43

+

GN

D2

+

C3

U1

GN

D1

C2

56

inpu

ta

21

78

GN

D1

+

C1

C10

D12

(Isol

ated

)-1

5V

(Isol

ated

)

(Isol

ated

)-1

5V

+15V

+15V

(Isol

ated

)

C

-15V

(Isol

ated

)

Q4

D4

Rg

ON

Rg

OFF

B

E

Q3

D3

b

Rb

Eb

Gb

(Isol

ated

)

+15V

(Isol

ated

)

-15VR

g O

FF

Q2

D2

D1

Ea

Rb

-+

7815

C24

2

3

+-

GN

D2

C20

2

7915

3

C23

C21

-+

+

1D

19

D20

D18

C16

+ -C

19

1+-

D17

b-+

C18

2

7815

3

+-C

14

7915

3

2

D13

C17

C15

-+

+ -

1

D15

D14

C13

-+

1+

+15V

(Isol

ated

)

(Isol

ated

)

Rg

ON

B

ECQ

1a

+15V

Ga

+

GN

D1

a-

C12

2

7815

3

C11 C

9-

-+

1 +D

11

-

D10D9

1. U

1,U

2,U

3,U

4- H

CP

L-31

20 (A

gile

nt T

echn

olog

ies)

8 p

in D

IP

Pow

er M

OSF

ET /

BIM

OS

FETS

/ IG

BT

Gat

e D

rive

Opt

o-co

uple

r2.

Q1,

Q3,

Q5,

Q7-

2N

4401

NPN

BJT

for d

rivin

g sm

all t

o m

ediu

m p

ower

I

GBT

S/B

I-MO

SFE

TS/M

OSF

ETS

.3.

Q2,

Q4,

Q6,

Q8-

2N

4402

PN

P B

JT fo

r driv

ing

smal

l to

med

ium

pow

er

IGB

TS/B

I-MO

SFE

TS/M

OSF

ETS

.

or2.

Q1,

Q3,

Q5,

Q7-

ZTX

450

NPN

BJT

for d

rivin

g m

ediu

m p

ower

IG

BTS

/BI-M

OS

FETS

/MO

SFE

TS.

3. Q

2,Q

4,Q

6,Q

8- Z

TX55

0 PN

P B

JT fo

r driv

ing

med

ium

pow

er

IGB

TS/B

I-MO

SFE

TS/M

OSF

ETS

.

or2.

Q1,

Q3,

Q5,

Q7-

TIP

41C

NPN

BJT

for d

rivin

g hi

gh p

ower

I

GBT

S/B

I-MO

SFE

TS/M

OSF

ETS

.3.

Q2,

Q4,

Q6,

Q8-

TIP

42C

PN

P B

JT fo

r driv

ing

high

pow

er

IG

BTS/

BI-M

OSF

ETS

/MO

SFE

TS.

or

2. Q

1,Q

3,Q

5,Q

7- B

D74

3C fo

r driv

ing

very

hig

h po

wer

I

GBT

S/B

I-MO

SFE

TS/M

OSF

ETS

.3.

Q2,

Q4,

Q6,

Q8-

BD

744C

for d

rivin

g ve

ry h

igh

pow

er

IG

BTS/

BI-M

OSF

ETS

/MO

SFE

TS.

4. D

1 to

D8-

18

Volt,

400

mW

zen

er d

iode

s.5.

Rb-

2K

2,2W

6. R

g O

N- D

epen

ds o

n th

e M

OS

FET/

BI-M

OSF

ETS

/IGBT

bei

ng d

riven

.

Thi

s re

sist

or d

eter

min

es "t

urn

on" s

peed

of M

OSF

ET/

BI-

M

OSF

ETS

/IGB

T.7.

Rg

OFF

- Dep

ends

on

the

MO

SFET

/BI-M

OSF

ETS

/IGBT

bei

ng d

riven

.

Thi

s re

sist

or d

eter

min

es "t

urn

off"

time.

Rg

OFF

can

be

kept

m

uch

smal

ler t

hen

Rg

ON

to im

prov

e tu

rn o

ff ch

arac

teris

tics.

N

ote

: Som

e ap

plic

atio

ns u

se S

chot

tky

Rec

tifie

rs (s

ay 1

N58

22) i

n

plac

e of

Rg

OFF

or u

se R

g O

FF in

ser

ies

with

Sch

ottk

y R

ectif

ier

8. C

1 to

C8-

22M

FD, 2

5VD

C T

anta

lum

Cap

acito

rs9.

C9,

C15

,C21

- 100

0MFD

, 35V

DC

10. C

10,C

16,C

22- 4

70M

FD, 3

5VD

C11

. C11

,C17

,C23

- 22M

FD, 3

5VD

C12

. C12

,C18

,C24

- 100

0MFD

, 35V

DC

13. C

13,C

14,C

19,C

20,C

25,C

26,-

22M

FD, 3

5VD

C14

. D9

to D

21- D

SEP

8-1

2A

Q1.

..Q8=

TO-2

20

7815

,791

5--T

O-2

20

Use

Mot

orol

a M

C78

T15C

T

Ed

Gd

Eb

B C

E

Gb

N

LED

D25

20k,

5wFus

eL

C

B

E


12


Fig.

(6) M

OS

FET/

BI-M

OSF

ET/IG

BT

Driv

er C

ircui

t with

opt

o-is

olat

ion

for 3

ø In

vert

er B

ridge

C31

inpu

tf

432

GN

D4

+C1257

U6

100

6

inpu

t

inpu

t

18

1

d

3 42

C10 8

C11 +

GN

D4

GN

D4

+

57

U5

610

0

c

4321

U4

+G

ND

4C

9

GN

D4

+C8578

100

6

Rb

(Isol

ated

)-1

5VRg

OFF

Rg

ON

Q12

E

D12

D11

EfGf

(FO

R R

EFE

REN

CE

)3ø

Inve

rter B

ridge

-15VGN

D4

d

Rb

(Isol

ated

)

(Isol

ated

)+1

5V

Q11

C

B

-15V

f

Rg

ON

Rg

OFF

Q10

E

B

D10D9

EdGd

Rb

Q8

D8

(Isol

ated

)

(Isol

ated

)

Q9+1

5V

C

-15VR

g O

N

Rg

OFF

Q7

EC

B

D7

c

EcGc

EdGd

EbGb

Sc

Ec

Gc

Ea

Sa

Ga

Sd

Ef

Gf

Ee

Sf

Sb

H.V

.

Ge

Se

C36

+-

3

2

7915

1+-

C35

+ -

-

C32

D28

inpu

t

inpu

t

4

e2 31

5 +

+

GN

D4

C7

GN

D3

U3

C678

100

6

4

b

321

5 +G

ND

3

GN

D2

C5

+

U2

C478+

GN

D2

100

6

inpu

t

C1

3 4

a21

6 5

C2

GN

D1

C3

+

U1

78+G

ND

1

100

(Isol

ated

)

(Isol

ated

)

(Isol

ated

)

(Isol

ated

)

+15V

(Isol

ated

)

Rb

(Isol

ated

)

(Isol

ated

)+1

5V

-15V

Q6

D6

Rg

ON

Rg

OFF

E

Q5

B

C

D5

e

Ee

cd

Ge

-15V

e

Rb

D3

(Isol

ated

)-1

5V

+15V

Q4

D4

Rg

OFF

Rg

ON

(Isol

ated

)

E

Q3

C

Bb

Eb

+15V

Gb

-15V

b

+15V

+

C34

f-+

378

15

2+ -1

C30

C28

+-

3

GN

D3

-+

7915

2

1

2-

C33

+

D26

D27

D25

+-C

26

C29

+ -C25

-

C27

+

D24

D23

C24

3

+-

7815

1

2

C22

GN

D2

3

-+

3

7915

1

7815

2-+1

C23

+ -

D21

D22

+-

C19

-

C20

C21

+

D20

D18

D19

(Isol

ated

)

(Isol

ated

)R

b

Rg

OFF

(Isol

ated

)-1

5V

+15V

Q2

D2

D1

Rg

ON

(Isol

ated

)

B

E

+15V

Q1

C

a

Ea

-15V

Ga

a

+15V

C18

+-

379

15

2

1

C16

GN

D1

+ -

3

2+ -

7815

1

C14

+

C17

+ -

D17

-

C13

-

C15

+D

15

D16

D14D13

1. U

1,U

2,U

3,U

4,U

5,U

6- H

CP

L-31

20 (A

gile

nt T

echn

olog

ies)

8 p

in D

IP

P

ower

MO

SFE

T/BI

-MO

SFE

TS/IG

BT

Gat

e D

rive

opto

-cou

pler

2. Q

1,Q

3,Q

5,Q

7,Q

9,Q

11- 2

N44

01 N

PN

BJT

for d

rivin

g sm

all t

o m

ediu

m p

ower

IGB

TS/B

I-MO

SFE

TS/M

OS

FETS

.3.

Q2,

Q4,

Q6,

Q8,

Q10

,Q12

- 2N

4402

PN

P B

JT fo

r driv

ing

smal

l to

med

ium

pow

erIG

BTS

/BI-M

OS

FETS

/MO

SFE

TS.

or

2. Q

1,Q

3,Q

5,Q

7,Q

9,Q

11- Z

TX45

0 N

PN

BJT

for d

rivin

g m

ediu

m p

ower

IGB

TS/B

I-MO

SFE

TS/M

OS

FETS

.3.

Q2,

Q4,

Q6,

Q8,

Q10

,Q12

- ZTX

550

PN

P B

JT fo

r driv

ing

med

ium

pow

erIG

BTS

/BI-M

OS

FETS

/MO

SFE

TS.

or

2. Q

1,Q

3,Q

5,Q

7,Q

9,Q

11- T

IP41

C N

PN B

JT fo

r driv

ing

high

pow

erIG

BTS

/BI-M

OS

FETS

/MO

SFE

TS.

3. Q

2,Q

4,Q

6,Q

8,Q

10,Q

12- T

IP42

C P

NP

BJT

for d

rivin

g hi

gh p

ower

IGB

TS/B

I-MO

SFE

TS/M

OS

FETS

.

or2.

Q1,

Q3,

Q5,

Q7,

Q9,

Q11

- BD

743C

for d

rivin

g ve

ry h

igh

pow

er IG

BTS

/BI-M

OSF

ETS

/MO

SFE

TS.

3. Q

2,Q

4,Q

6,Q

8,Q

10,Q

12- B

D74

4C fo

r driv

ing

very

hig

h po

wer

IGB

TS/B

I-MO

SFE

TS/M

OS

FETS

.

4. D

1 to

D12

- 18

Volt,

400

mW

zen

er d

iode

s.5.

Rb-

2K

2,2W

6. R

g O

N- D

epen

ds o

n th

e M

OS

FET/

BI-M

OS

FETS

/IGB

T be

ing

driv

en.

Th

is re

sist

or d

eter

min

es "

turn

on"

spe

ed o

f MO

SFE

T/BI

-MO

SFE

TS/IG

BT.

7. R

g O

FF- D

epen

ds o

n th

e M

OS

FET/

BI-M

OSF

ETS

/IGBT

bei

ng d

riven

.

This

resi

stor

det

erm

ines

"tu

rn o

ff" ti

me.

Rg

OFF

can

be

kept

muc

h sm

alle

r the

n

Rg

ON

to im

prov

e tu

rn o

ff ch

arac

teris

tics.

N

ote

: Som

e ap

plic

atio

ns u

se s

witc

hing

dio

de (s

ay IN

4148

or I

N91

4) in

pla

ce o

f

Rg

OFF

or u

se R

g O

FF in

ser

ies

with

sw

itchi

ng d

iode

. 8.

C1

to C

12- 2

2MFD

, 25V

DC

Tan

talu

m C

apac

itors

9. C

13,C

19,C

25,C

31- 1

000M

FD, 3

5VD

C10

. C14

,C20

,C26

,C32

- 470

MFD

, 35V

DC

11. C

15,C

21,C

27,C

33- 2

2MFD

, 35V

DC

12. C

16,C

22,C

28,C

34- 1

000M

FD, 3

5VD

C13

. C17

,C18

,C23

,C24

,C29

,C30

,C35

,C36

- 22M

FD, 3

5VD

C14

. D13

to D

29- B

A159

Fuse

20k,

5w

LED

D29

NL

Q1.

..Q12

=TO

-220

7815

,791

5--T

O-2

20

B C

E


13


Fig.

(7) Z

CS

Res

onan

t Mod

e In

vert

er C

ontr

olle

r Circ

uitR

3

Rm

in

Cvc

oSo

ft R

ef.

sens

e cu

rren

t in

inve

rter b

ridge

LOC

110,

LOC

111

or L

OC

112

C3

Brid

ge

2 43

I

V 0-2V

100p

F

F

IN

1

Inve

rter

From R

10

56781

2

OU

T0-

8V1

VccC

.T.

Vcc

V

Vcc

C5

P5

R5

P3P4

C2

Hal

l effe

ct tr

ansd

ucer

to

R7

C5

1687

951

C4

UC

3865

2

Rra

nge

6310

R6

4

R2

15

1412

R9

R8

Vcc2

: 18V

DC

1113

R1

P1

DR

IVER

CIR

CU

IT

LinTOHin

I 1

U1

U2

+

++

--

-

2Vc

c

Vcc2

LM31

7TVi

n

++

--

VOU

T

Adj

ust

U3

U4

U2

C14

R4

C.T

.

7815

Vin

++

--

VO

UT

Mai

ns

D6

D5

D8

D7

C8

C13

C9

C11

C12

C10

P6R

11

Vcc1

R12


14


1 U1 OP177FP2 U2 OP177FP3 U3 LOC110 or LOC111 or LOC 112 are Linear Opto-Couplers from Clare,inc (An IXYS Company)4 U4 UC38655 P1,P2,P3,P4 20K TRIMPOT Multi Turn BOURNS6 P5 10K TRIMPOT Multi Turn BOURNS7 D1,D2,D3,D4 1N58198 D5,D6,D7,D8 1N40029 R1,R2,R5,R6 1K Ohm All resistors are 1% metal Film,1/4 W10 R3,R8,R9 10K Ohm11 R4 33K Ohm12 R7* 4.16K Ohm13 R10 133K Ohm14 Rmin** 6.8K Ohm15 R11 270 Ohms16 C1,C4 1uf/35v Tantalum17 C2,Cosc 10nf Multilayer Ceramic18 C5 1nf Multilayer Ceramic19 C6 2nf Multilayer Ceramic20 C3 0.1uf/35V Tantalum21 C7 22uf/35V Tantalum22 C8,C10 2200uf/35V Electrolytic23 C9,C11 220uf/35V Electrolytic24 C12,C13 0.1uf/35V Multilayer Ceramic26 C14 100pf Silver Dipped Mica or Polystyrene

1. Supply Voltage for Design

Vcc = 18Vdc for UC3865

2. For given value of “Rmin & Cosc” Maximum Output frequency = 38.3 kHz when feedback is not given and when Reference Voltage = 5Vdc. Minimum output frequency = 18.65kHz when feedback is greater than reference Voltage = 5Vdc.

3.Value of “R7 & C6” Decides Ton(max) and Ton(min)

Ton(max) = 1.2 * R7 * C6 For given design it is 8.28 us

Ton(min) = 0.3 * R7 * C6For a given design it is 800 ns

For this design Ton(max) is limited to 13us With C6 = 4 nf ; greater value of C7 causes no effect on Ton maximum.4: In output, Ton Depends upon the current sensing. Output overload/short-circuit is set by setting the value P1 (Multiturn trim-pot) .5. In output, Frequency depends upon feedback Voltage.6. R5, R6, C2, C5, P3 & P5 form Lead-Lag network for stability in output. They have to be trimmed, depending upon many parameters that can’t all be predetermined.

Bill of Materials and testing procedure for Fig.(7)


15


Fig.

8. S

chem

atic

, sho

win

g us

e of

IXB

D44

10/4

411

for

driv

ing

Bi-M

osfe

ts, c

onne

cted

in p

hase

-leg

conf

igur

atio

n.


16


C1,

C3

: 22

MFD

, 25V

DC

Tan

talu

m c

apac

itors

D1

RG

Rp

ZD1

ZD2

RSCS

C E

GQ

+15V

DC

H.V

.DC

C1R

1

1 2 3 45678

V

TIM

EINPU

TIC

2

D2 D3

C2IC

1

C3

T1

+15V

DC

+

C.T

.

C2

: 220

0 M

FD, 3

5VD

C E

lect

roly

tic c

apac

itors

T1 :

220

VAC

to 1

5-0-

15 V

AC, 1

5VA

cont

rol t

rans

form

er11

0VAC

TO

15-

0-15

D2,

D3

: IN

4002

IC2

: IXD

D40

8 or

IXD

D41

4D

1 : I

N58

17

IC1

: 781

5 R

egul

ator

Cs,

Rs

: Snu

bber

net

wor

k to

redu

ce IG

BT

switc

hing

R

p : 2

K2,

¼ W

, 5%

RG

1 : 3

.3 o

hms

to 2

7 oh

ms

ZD1,

ZD2

: 18V

, 400

MW

ZE

NER

S

Cs=

0.1

MFD

, Rs=

10 to

33

ohm

s

Fig.

(9) C

ircui

t sch

emat

ic s

how

ing

how

to u

se IX

DD

408

or I

XDD

414

to d

rive

IXLF

19N

250A

loss

es. V

alue

dep

ends

upo

n fs

w. S

ugge

st:

depe

ndin

g on

Tur

n-O

N s

peedL O A D

R1

: 10K

, ¼ w

ixan0013.pdf

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