turn-on performance comparison of current- source vs ... · the gate drive loop has no influence on...

Frank Wolfgang, Zheng ZiqingInfineon Technologies

Turn-on performance comparison of current-source vs. voltage-source gate drivers

Copyright © Infineon Technologies AG 2018. All rights reserved. 2

Content

Introduction

Gate driver boards

Double pulse test result

Summary

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Agenda

Introduction

Gate driver boards


Summary

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What does “current-source” and “voltage-source” gate drivers mean?

› Current sources have a high resistive output by default.

› Any additional voltage drop in the gate drive loop has no influence on the gate current Ig (inside limits).

› Supposed to damp oscillations

› Voltage sources shall be as low resistive as possible.

› Any additional voltage drop in the gate drive loop has immediate influence on the gate current Ig.

› Prone to oscillations

Current source Voltage source

CGD

CGSCDS

RintLG

IG

LSC

Idr +

-

+-

Is

VDS

CGD

CGS

CDS

Rint

Ron

LGIG

LSC

Vdr+

-

+-

Is

VDS

Copyright © Infineon Technologies AG 2018. All rights reserved.

Comparison of gate driver IC functions

› Isolated gate driver

› Current source control for turn-on integrated

› Adjustability of swiching speed from input side on-the-fly

› DESAT

› Current sense input

› Optional Two-level turn-off

› Soft turn-off

› Precise output side monitoring

› Isolated gate driver

› 2 A output capability

› Adjustability of swiching speed by manual change of Rg

› DESAT

› ---

› Optional Two-level turn-off

› ---

› Limited output side monitoring

Current source (1EDS20I12SV) Voltage source (1ED020I12-F2)



Agenda

Introduction

Gate driver boards


Summary

1

2

3

4

no marking

Driver boards for FF1200R12IE5 1200 A / 1200 V power module

› The same design and layout philosophy applies to both designs

› Approximately the same number of components per board


1EDS20I12SV

Bias spupply

Output buffer

Active clamping

1ED020I12-F2



Agenda

Introduction

Gate driver boards


Summary

1

2

3

4

no marking

Test bench and test pulse timing

VIN

T1

T2

D1

D2

L

iL(t)

iT(t)

iD(t)

vG2

vG2

tTon1 Ton2

ToffCapacitor bank

Wide bandwidth

Pearson probe

Power Module FF1200R12IE5

Gate driver board under

test

-9 V


Switching waveform comparisonVDC = 600 V, IC = 120A, Tvj = 25°C

Level 1 Level 11Level 5

Curr

ent

sourc

e

(1ED

S20I1

2SV)

Voltage s

ourc

e

(1ED

020I1

2-F

2)

Rg = 4.7 W Rg = 2.2 W Rg = 0.4 W

Slow (3 V/ns) Normal (5 V/ns) Fast (9 V/ns)

200 V/div 200 V/div 200 V/div

500 V/div 500 V/div 200 V/div

Stronger tendency for oscillations


Commutation speed (dvF/dt) comparison

› Current source IC keeps dv/dt constant over load range!

› Easy to obtain test results due to simple change of speed from input side

› Speed is a decreasing function because Rgint reduces driving voltage, thus the gate current

› Manual change of Rg for every branch of diagram


Low load (dvF/dt) ≈5 V/ns @2.2 W

Low load (dvF/dt) ≈5 V/ns @ level5

Hi load (dvF/dt)

≈5 V/ns @ level5

Hi load (dvF/dt) ≈2.2V/ns @2.2 W


Turn-on energy Eon comparison

› Turn-on energy is a linear function

› Turn-on energy is a non-linear function


Current source method has much lower turn-on losses over load range when starting at the same low load condition !

Starting with <30mJ@120A

Ending with 140mJ@1200A

Starting with <30mJ@120A

Ending with 320mJ@1200A



Agenda

Introduction

Gate driver boards


Summary

1

2

3

4

no marking

Summary

The design effort of schematic and layout is equal for current source and voltage source gate driver boards.

Eon at full load (Inom) is less than 50% for the same dvF/dt condition at low load (1/10 Inom) when using the current source gate driver.

Current source gate drivers such as 1EDS20I12SV overcome parasitic effects which influence the gate drive loop.


turn-on performance comparison of current- source vs ... · the gate drive loop has no influence on...

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