1. IGBT driving aspect
Zhou Yizheng

2. IGBT driving Driving voltage level Effect of turn on/off Isolation
Rge, Cge, Lg
Driving capability
Isolation
Thermal
Protection
Parasitic turn on
Over voltage
Short circuit/over current

3. Driving voltage level Positive voltage Effect to Vcesat Vge，Vcesat
Tvj=125C
Positive voltage
Effect to Vcesat
Vge，Vcesat
note：max. allowed Vge is 20V
Tvj=125C
Effect to short cicuit
Vge，Isc（tsc）

4. Driving voltage level Negative voltage Miller capability effect
To guarantee safety off state, avoid parasitic miller turn on
Turn on delay increase (dead time)
Slightly reduce tf and Eoff
Increase driving power
Miller capability effect

5. Effect of turn on/off Rgon
Control of dv/dt and di/dt with gate resistor
Turn-on with smaller than nominal gate resistor:
dv/dt = 1.4kV/µs
di/dt = 8.7kA/µs
ICpeak = 2.7kA
Eon = 544mWs
Turn-on with nominal gate resistor (datasheet value):
dv/dt = 0.9kV/µs
di/dt = 6.4kA/µs
ICpeak = 2.4kA
Eon = 816mWs
Turn-on with larger than nominal gate resistor:
dv/dt = 0.3kV/µs
di/dt = 3.0kA/µs
ICpeak = 1.8kA
Eon = 2558mWs

6. Effect of turn on/off Rgoff
Control of dv/dt and di/dt with gate resistor
dv/dt is controllable with gate resistor. A larger resistor will result in a smaller dv/dt.
di/dt is only controllable if the gate voltage doesn’t drop below the Miller Plateau level before IC starts to decrease. This is in general the case for a gate resistor value close to the datasheet value. With larger resistors a control of di/dt starts to work.

7. Effect of turn on/off Cge Range Determined by Condition Influenced by
Independently control of dv/dt and di/dt
Range
Determined by
Condition
Influenced by
Influence on 1
VGE < VGEth
Ciss = const
RG, CGE
tdon 2
VGEth < VGE < VGEM
di/dt 3
VGE = VGEM
VGE = const
RG, CGC
dv/dt

8. For similar Eon, we can: Rge Cge Eon Di/dt Ipeak tdon Vge_p 4.6ohm 0nf
650mJ
3283kA/ us
1.487kA
1.76us
13.6V
1.7ohm
200nf
635mJ
2492kA/ us
1.386kA
1.67us
13.7V
4.6ohm0nF
1.7ohm200nF

9. For similar di/dt, we can:
Rge
Cge
Eon
Di/dt
Ipeak
tdon
Vge_p
2.6ohm
0nf
437mJ
4270kA/ us
1.639kA
1.29us
14.0V
1.7ohm
46nf
386mJ
4324kA/ us
1.635kA
1.23us
15.0V
2.6ohm0nF
1.7ohm46nF

10. Rge vs. Cge Using Cge shows better Eon*di/dt coefficient
Using Cge can significantly increase driving power
P=∆U*(Qge+Cge*∆U)*f
Using Cge can significantly increase driving peak current, require more powerful driver (output peak current capability)
The tolerance of Cge should be taken care when used in IGBT paralleling application
Using Cge may cause gate current oscillation, which leads to higher gate peak voltage.

11. Cable length influence
With short cable
With long cable
Calbe
Rge
Cge
Eon
Di/dt
Ipeak
tdon
Vge_p
Short
0.9ohm
0nf
196mJ
6128kA /us
1.978k A
0.92us
14.7V
Long
87mJ
6920kA /us
2.220k A
18.3V

12. For similar Eon, we can: With fixed Cge With fixed Rge Calbe Rge Cge
Di/dt
Ipeak
tdon
Vge_p
Short
0.9ohm
22nf
210mJ
5882kA /us
1.908k A
0.92us
17.0V
Long
1.7ohm
231mJ
5587kA /us
1.874k A
1.21us
17.5V
Calbe
Rge
Cge
Eon
Di/dt
Ipeak
tdon
Vge_p
Short
1.7ohm
22nf
351mJ
4717kA /us
1.711k A
1.17us
15.8V
Long
91nf
347mJ
4065kA /us
1.673k A
1.39us
15.6V

13. Cable length influence
Cable length (Lg) shows similar Eon*di/dt coefficient as Rge, This mainly due to Lg effect both during di/dt period and dv/dt period (same as Rge)
Long cable significantly induce the turn on delay time
Long cable is a EMI receiver, which can cause Vge spike and unstable.
Loosing gate cable inductance will significantly increase Eon, which should especially paid attention in active adaptor design.
Adaptor board
Rge
Cge
Eon
Di/dt
Ipeak
Active
1.0ohm
0nf
332mJ
5650kA/us
1.708kA
Passive(8mm)
187mJ
7700kA/us
1.895kA
Long cable should be avoid to be used. But loosing gate inductance should also be paid attention

14. Effect of turn on/off Driving capability
Peak current capability
Power capability
Maximum driver peak current U = 15V switching
Driver power
Slow down turn on/off speed
Driver losses
Vge goes down
Power supply losses

15. Effect of turn on/off Turn on/off criteria
Redundant information on di/dt and dv/dt 1 2 3 !
1000
2000
3000
VR(t) [V]
IR(t) [A]
locus iR(t)*vR(t) 1 2 3 !
Diode SOA

16. + - Isolation Optocoupler Optical Fiber High isolation capability
Aging of electrical characteristic
Reduced reliability due to aging
No energy transmission
Monolithic Level Shifter
Cost effective
Integration of logic suitable
No galvanic isolation
EMI sensitivity
Discrete Transformer
Very high isolation Capability
Energy transmission possible
Expensive
Device Volume
Coreless Transformer (CLT)
Very cost effective
Easy integration of logic function

17. Isolation Isolation transformer Isolation test Partial discharge test
Parasitic capacitor (Primary - secondary)

18. Thermal Influenced parameters Module case temperature
Driving power (switching frequency, Qg)
Driving peak current
Sensitive parts
Gate resistor
Booster
Power supply
Fiber

19. Thermal If system internal ambient temperature is known.
From delt Tca, we can check temperature rise due to module itself heating
Adding temperature rise due to driving signal, real driver board temperature can be gotten.
System cooling can significant improve driver cooling condition

20. Protection UVLO Interlock / generating deadtime Vge over voltage
Parasitic turn on
Short circuit protection
Over voltage protection (for short circuit off)
Active Clamping
DVRC (Dynamik Voltage Raise Control)
di/dt-Feedback
Soft-Shut-Down
Two-Level Turn-off

21. Protection UVLO Interlock / generating deadtime
Avoid driving IGBT with low voltage causing thermal issue
Avoid series break down
Interlock / generating deadtime
Avoid short through by software mistake
Hardware deadtime should be shorter than software deadtime

22. Gate-Emitter Clamping
Protection
Limitation of increase of gate voltage due to positive feedback over CGC and due to di/dt
Limitation of short circuit currents
Vge over voltage
Methode 1
Gate-Supply Clamping
Methode 2
Gate-Emitter Clamping

23. Protection Parasitic turn on minus voltage off
separate gate resistors, using small Rgoff and big Rgon
Additional gate emitter capacitor to shunt the Miller current
Active Miller clamping

24. Protection Short circuit protection Desaturation detect Vce Ic Vce Ic
SC I Ic
Vce OC
SC II

25. Protection Short circuit protection Desaturation detect
Based on fixed reference voltage
Based on variable reference voltage

26. Protection Short circuit protection Desaturation detect
Over current protection?
Noise immunity is poor
Blanking time hard to set for fixed reference voltage concept, especially for high voltage module
Current protect point hard to be accurate
Directly detect collector current
Digital controller to detect di/dt
By system current sensor

27. Protection
Over voltage protection
Active clamping

28. Protection Over voltage protection
DVRC (Dynamic Voltage Raise Control)
uGE(t)
iC(t)
uCE(t)
dic/dt=11kA/µs
@ Tj=25°C
RG=3.6W
EOFF=0.9J
+16V
-16V
PWM
IRFD 120
UF4007
100pF
RG=1.5W
FZ2400R17KE3
47R
15R
ZPD16
RMOS 56
BYD77
44H11
45H11
MFP-D
MFN-D
3xSM6T220A
RAC=15W
4xSM6T220A
UAC
URAC
uGE(t)
iC(t)
uCE(t)
dic/dt=3.4kA/µs
@ Tj=25°C
RG=13W
EOFF=1.95J

29. Protection
Over voltage protection
di/dt protection

30. Protection
Over voltage protection
Soft shut down

31. Protection Over voltage protection Two level turn off VGE Driver Out
VCE
VCE IC IC
Without Two-Level Turn-Off VCE reaches 1000V
With Two-Level Turn-Off VCE reduced to 640V