~today and future~ - psma.com · 2012-04-07 · development of multi layer power inductor we are...

New Frontier Spirits

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Measurement and Development of Low

AC power loss multi layer inductor

08. Feb. 2012

~Today and Future~

Applied Power Electronics Conference and Exposition 2012

Kiyohisa Yamauchi

FDK corporation


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Development of Multi Layer Power Inductor

We are optimizing multi layer inductor for DC DC converter

and introducing it quickly to the market.

Ferrite technology

Fine printing technology

CAE technology

Market requirement of power inductor for mobile device

High converting efficiency on Power supply

Small

Low Leak Noise

Combining FDK unique technology

Solution

2


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Classification of General Power Inductor

Comparison of the characteristic

Magnetic

Material

Leak

Noise miniaturize

Frequency

properties

Efficiency DC Bias

Characteristic Low

DC

High

DC

Wire

Wounded Ferrite

1 2 3 2 3 3

Multi

-Layer 4 4 4 4 3 2

Metal

Molded Metal 4 1 2 2 3 4

Structure (cross section schematic draw)

Wire Wounded

Cu coil Ferrite

Multi Layer

Ag coil Ferrite

Metal Molded

Cu coil Metal

3

Score: Bad=1~Best=4


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0.9

1.0

1.0

11.1

2.0

0.00 2.30 MAGNETIC FLUX DENSITY

[mT at 0.2A]

1.15

5.5

3.2

9.6

1.0

1.0

1.0

Multi Layer

Wire

Wounded

Multi Layer:3.2 * 2.6 * 1.0mm , 10uH

Winding:2.8 * 2.6 * 1.0mm , 10uH

Feature of Multi Layer Power Inductor(1)

Low Leakage Flux(Simulation Result)


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Miniaturize(including thickness)

Smallest package size: 1.6x0.8mm

Lowest profile : 0.5mm

3.2x2.5

Unit:mm

2.5x2.0

2.0x1.6

2.0x1.2

1.6x0.8

Package Size

H:1.2mm

H:1.0mm

H:0.5mm

Profile

5


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High converting efficiency


Inductance vs. DC bias current

0

0.5

1

1.5

2

2.5

3

3.5

4

0 100 200 300 400 500 600 700 800

DC bias current(mA)

Ind

uct

ance

(uH

)

MIPS2520D2R2

NR3010T-2R2M

Efficiency

Buck, 2MHz, PWM, Vin=3.6V, Vout=1.8V

10

20

30

40

50

60

70

80

90

100

1 10 100 1000

Load current(mA)

Eff

icie

ncy

(%)

MIPS2520D2R2

NR3010T-2R2M

Multi Layer

Wire Wounded

Multi Layer

Wire Wounded

Usage in power supply

Inductor

RDC of Multi layer and wire wounded is

same as 0.11Ohm.

6


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Efficiency


10

20

30

40

50

60

70

80

90

100

1 10 100 1000

Load current(mA)

Eff

icie

ncy

(%)

MIPS2520D2R2

NR3010T-2R2M

Multi Layer

Wire Wounded

AC Power Loss

Advantage DC Power Loss

Advantage

Efficiency(%) = 100 - (Switching Loss(%) + Inductor

Loss(%)) Inductor Loss = AC Power Loss + DC Power Loss

(AC Resistance) (DC Resistance)

Efficiency & Inductor Characteristic

7


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Reducing AC power loss

Inner Structure of inductor

Magnetic Material

Method of reducing AC power loss

About inner structure

Optimizing the shape of coil pattern,

coil thickness, other dimension by

CAE technology. Magnetic flux at same DC bias

Previous Optimizing inner structure

Optimizing

Material composition Sintering condition And more

Low AC Power

Loss Material

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Reduction of AC power loss(Material)

Development of low loss magnetic material

0

200

400

600

800

1000

1200

1400

1600

0 2 4 6 8 10 12

Frequency(MHz)

Co

re L

oss

(W/m

3)

Material A

Material B

Material A: Original magnetic material

Material B: New material for higher frequency

Fig. SEM image of ferrite

material

Material A

Material B

Reducing AC power loss


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Reduction of AC power loss(Structure)

ACR

type A > type B > type C

Frequency vs. ACR at 10mArms

0

2

4

6

8

10

12

0 1 2 3 4 5 6 7

Frequency(MHz)

AC

R(O

hm

)

type A

type B

type C

type A A 0.08

type B A 0.11

type C B 0.11

L(uH)

at 0mA

2.2

Magnetic

Material

RDC

(Ohm)

Size

(mm)

2.5x2.0x1.0

Type A: Before optimizing inner structure,

applied magnetic material A

Type B: Optimizing inner structure,

applied magnetic material A

Type C: Same structure as type B,

applied magnetic material B

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How to measure by large amplitude?

How much is AC resistance at power supply working on?

AC power loss measurement based on actual usage

General at Measure

<20mA rms

On Actual usage

>20mA rms

Measurement:

Agilent 4284A(Irm 10mA)

Measurement:

Oscilloscope

Sw

IL

IL=58mA_rms

*Iout=at 200mA


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ACR Measurement by BH Analyzer

Frequency

(MHz) Amplitude Measurement method

BH analyzer

(SY-8232 Iwatsu)

<10MHz >1Ap-p

Impedance analyzer

(4284A Agilent)

<110MHz <20mArms

AC power loss measurement by BH Analyzer

Zx(ACR)

V V ~

R Oscillator

V1

V2

Zx(ACR)

I ~

Oscillator Zx=V1/I


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Measurement result by BH analyzer

Frequency vs. ACR at 60mArms

0

2

4

6

8

10

12

0 1 2 3 4 5 6 7Frequency(MHz)

AC

R(O

hm

)

type A

type B

type C

At 3MHz

10mA rms 60mA rms

Type A 2.4 ohm 4.1 ohm

Type B 1.3 ohm 1.4 ohm

Type C 0.6 ohm 1.2 ohm

Ex. Measurement Result

System:SY-8232 Iwatsu, IL=60mA rms, Frequency=1~6MHz

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0

10

20

30

40

50

60

70

80

90

100

(%)

type A

Other loss 37.3 13.9 9.3 7.4 9.4 11.6 14.0

AC loss 13.4 4.6 2.6 1.5 1.5 3.2 3.4

DC loss 0.0 0.3 0.7 1.4 3.4 5.1 6.0

Efficiency 49.3 81.2 87.4 89.6 85.8 80.2 76.6

0.01A 0.05A 0.1A 0.2A 0.5A 0.8A 1A

0

10

20

30

40

50

60

70

80

90

100

(%)

type B

Other loss 36.9 12.7 8.6 7.2 10.0 13.9 16.5

AC loss 5.9 1.8 1.0 0.5 0.3 0.2 0.3

DC loss 0.1 0.4 0.9 1.7 4.1 6.1 7.2

Efficiency 57.1 85.1 89.5 90.5 85.7 79.8 75.9

0.01A 0.05A 0.1A 0.2A 0.5A 0.8A 1A

0

20

40

60

80

100

(%)

type C

Other loss 36.3 12.4 8.5 7.2 10.0 13.9 16.6

AC loss 4.6 1.4 0.8 0.4 0.2 0.2 0.3

DC loss 0.1 0.4 0.9 1.7 4.1 6.1 7.2

Efficiency 59.1 85.8 89.9 90.7 85.7 79.8 75.9

0.01A 0.05A 0.1A 0.2A 0.5A 0.8A 1A

Loss Analysis Appling ACR by BH Analyzer

Efficiency


0

20

40

60

80

100

1 10 100 1000

Load Current(mA)

Eff

icie

ncy

(%)

type A

type B

type C

Irms vs. ACR

by BH analyzer

0

1

2

3

4

5

6

7

0 0.02 0.04 0.06 0.08 0.1 0.12

Irms(A)

AC

R a

t 3

MH

z(O

hm

)

type A

type B

type C

Inductor Loss:

AC loss=ACR x I(L)2

DC loss=DCR x I(load)2

14


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Direction of development to the future

Next Multi layer Power inductor

Corresponding to higher switching frequency(over 6MHz)

Starting development new magnetic material

Smaller

1608 size inductor has been achieved.

Starting development for 1005.

Thinner

0.5mm thickness has been achieved.

Starting development less than 0.3mm.

15


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Next Multi layer Power inductor(small and efficiency)

Frequency(MHz）

Siz

e, I

nd

uct

ance（

uH

)

3225

2520

2016

2012

1608 1005

1MHz 2MHz 3MHz 4MHz 5MHz 6MHz

4.7uH

2.2uH

3.3uH

1.5uH

1.0uH

0.5uH

2004~ 2006~ 2010~ 2012~

Magnetic Material1

(<3MHz)

Magnetic Material2

(<6MHz)

Magnetic Material3

(>6MHz))

16

Smaller and smaller

Higher efficiency

3226

2520

2016

2012

1608

1005

Next target

Achieved


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Next Multi layer Power inductor

0.5mm 0.3mm

Top Bottom

1.6mm

0.8mm

Thinner and Thinner

(0.3mm) Package Size:2.0*1.2mm 1.6*0.8mm

17


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Introducing Multi Layer power inductor

How to improving AC resistance

AC power loss measurement based on power supply usage

Next development(smaller, thinner, for higher frequency)

Summary

18


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Thank you for listening!

19

Contact:Kiyohisa Yamauchi

FDK Corporation

2281 Washizu Kosai-city, Shizuoka, Japan

Tel:+81-053-575-2621

Email:[email protected]

~today and future~ - psma.com · 2012-04-07 · development of multi layer power inductor we are...

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