IGBT driving aspect Zhou Yizheng IGBT driving Driving voltage level Effect of turn on/off ¬ Rge, Cge, Lg ¬ Driving capability Isolation Thermal Protection ¬ Parasitic turn on ¬ Over voltage ¬ Short circuit/over current Copyright © Infineon Technologies 2009. All rights reserved. Driving voltage level Tvj=125C Positive voltage Effect to Vcesat Vge,Vcesat note:max. allowed Vge is 20V Effect to short cicuit Vge,Isc(tsc) Copyright © Infineon Technologies 2009. All rights reserved. Tvj=125C Driving voltage level Negative voltage ¬ To guarantee safety off state, avoid parasitic miller turn on ¬ Turn on delay increase (dead time) ¬ Slightly reduce tf and Eoff Miller capability effect ¬ Increase driving power Copyright © Infineon Technologies 2009. All rights reserved. Effect of turn on/off Rgon Control of dv/dt and di/dt with gate resistor Turn-on with smaller than nominal gate resistor: Turn-on with nominal gate resistor (datasheet value): Turn-on with larger than nominal gate resistor: dv/dt = 1.4kV/µs di/dt = 8.7kA/µs ICpeak = 2.7kA Eon = 544mWs dv/dt = 0.9kV/µs di/dt = 6.4kA/µs ICpeak = 2.4kA Eon = 816mWs dv/dt = 0.3kV/µs di/dt = 3.0kA/µs ICpeak = 1.8kA Eon = 2558mWs Copyright © Infineon Technologies 2009. All rights reserved. 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. Copyright © Infineon Technologies 2009. All rights reserved. Effect of turn on/off Cge 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 Ciss = const RG, CGE di/ dt 3 VGE = VGEM VGE = const RG, CGC dv/ dt Copyright © Infineon Technologies 2009. All rights reserved. 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 1.7ohm200nF 4.6ohm0nF Copyright © Infineon Technologies 2009. All rights reserved. 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 1.7ohm46nF 2.6ohm0nF Copyright © Infineon Technologies 2009. All rights reserved. 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. Copyright © Infineon Technologies 2009. All rights reserved. Cable length influence With long cable With short cable Calbe Rge Short Long Cge Eon Di/dt 0.9ohm 0nf 196mJ 0.9ohm 0nf 87mJ Ipeak tdon Vge_p 6128kA 1.978k /us A 0.92us 14.7V 6920kA 2.220k /us A 0.92us 18.3V Copyright © Infineon Technologies 2009. All rights reserved. For similar Eon, we can: With fixed Cge Calbe Rge Short Long Cge Eon Di/dt 0.9ohm 22nf 210mJ 1.7ohm 22nf Ipeak tdon Vge_p 5882kA 1.908k /us A 0.92us 17.0V 231mJ 5587kA 1.874k /us A 1.21us 17.5V Eon Di/dt tdon Vge_p With fixed Rge Calbe Rge Cge Ipeak Short 1.7ohm 22nf 351mJ 4717kA 1.711k /us A 1.17us 15.8V Long 1.7ohm 91nf 347mJ 4065kA 1.673k /us A 1.39us 15.6V Copyright © Infineon Technologies 2009. All rights reserved. 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) 1.0ohm 0nf 187mJ 7700kA/us 1.895kA Long cable should be avoid to be used. But loosing gate inductance Copyright © Infineon 2009. All rights reserved. should alsoTechnologies be paid attention Effect of turn on/off Driving capability ¬ Peak current capability Maximum driver peak current I Gmax ΔU R G(min) Slow down turn on/off speed ΔU Driver losses R G extern R G intern U = 30V @ 15V switching ¬ Power capability Driver power P tot PDriver PGate Vge goes down PGate f Q ΔU or PGate f 3...5 C iss ΔU Power supply losses 2 Copyright © Infineon Technologies 2009. All rights reserved. Effect of turn on/off Turn on/off criteria Redundant information on di/dt and dv/dt 3 2 2000 2000 IR(t) [A] Diode SOA V R [5 0 0 V/ d i v ] IR [ 5 0 0 A/ d i v ] 3000 1000 ! ! 1 1000 0 0 locus iR(t)*vR(t) 2 1000 0 2000 0 1 0 ti me [4 00ns/ di v] Copyright © Infineon Technologies 2009. All rights reserved. 1000 2000 VR(t) [V] 3 3000 Isolation + Optocoupler High isolation capability Optical Fiber Aging of electrical characteristic Reduced reliability due to aging No energy transmission Monolithic Level Shifter Cost effective No galvanic isolation Integration of logic suitable EMI sensitivity No energy transmission Discrete Transformer Very high isolation Capability Energy transmission possible Coreless Transformer (CLT) High isolation capability Expensive Device Volume No energy transmission Very cost effective Easy integration of logic function Copyright © Infineon Technologies 2009. All rights reserved. Isolation Isolation transformer ¬ Isolation test ¬ Partial discharge test ¬ Parasitic capacitor (Primary - secondary) Copyright © Infineon Technologies 2009. All rights reserved. Thermal Influenced parameters Module case temperature Driving power (switching frequency, Qg) Driving peak current Sensitive parts Gate resistor Booster Power supply Fiber Copyright © Infineon Technologies 2009. All rights reserved. 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. Pg T Tc Rth_1 System cooling can significant improve driver cooling condition Rth_2 Ta Copyright © Infineon Technologies 2009. All rights reserved. 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 Copyright © Infineon Technologies 2009. All rights reserved. Protection UVLO ¬ 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 Copyright © Infineon Technologies 2009. All rights reserved. Protection Vge over voltage ¬ Limitation of increase of gate voltage due to positive feedback over CGC and due to di/dt ¬ Limitation of short circuit currents Methode 1 Gate-Supply Clamping Methode 2 Gate-Emitter Clamping Copyright © Infineon Technologies 2009. All rights reserved. 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 Copyright © Infineon Technologies 2009. All rights reserved. Protection Short circuit protection Desaturation detect Vce Ic Vce Ic SC I OC Copyright © Infineon Technologies 2009. All rights reserved. SC II Protection Short circuit protection Desaturation detect Based on fixed reference voltage Based on variable reference voltage Copyright © Infineon Technologies 2009. All rights reserved. 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 Copyright © Infineon Technologies 2009. All rights reserved. Protection Over voltage protection ¬ Active clamping Copyright © Infineon Technologies 2009. All rights reserved. Protection Over voltage protection ¬ DVRC (Dynamic Voltage Raise Control) uGE(t) iC(t) UF4007 100 pF dic/dt=11kA/µs @ Tj=25°C 3xSM6T220A IRFD 120 47R UF4007 UAC 4xSM6T220A +16 V uCE(t) RG=3.6W EOFF=0.9J BYD77 RMO S 56 ZPD16 44H 11 MFP-D PWM 15R BYD77 MFN-D 45H 11 URAC RAC=15 W RG=1.5 W FZ2400R17KE3 uGE(t) iC(t) dic/dt=3.4kA/µs @ Tj=25°C -16V uCE(t) Copyright © Infineon Technologies 2009. All rights reserved. RG=13W EOFF=1.95J Protection Over voltage protection ¬ di/dt protection Gate boost Detect & comparison Copyright © Infineon Technologies 2009. All rights reserved. Protection Over voltage protection ¬ Soft shut down Rg Rssd Copyright © Infineon Technologies 2009. All rights reserved. Protection Over voltage protection ¬ Two level turn off Driver Out IC VGE Driver Out VCE Without Two-Level Turn-Off VCE reaches 1000V IC VGE VCE With Two-Level Turn-Off VCE reduced to 640V Copyright © Infineon Technologies 2009. All rights reserved.