IGBT are widely used in the filed of power electrinics nowadays,IGBT and IGBT driver take an essential part in the converter system. As the reliability of coverter syetem are determined by the selection of the driver and the calculation of output power, the shortage power of driver or a wrong selection may result in damage to driver,we should pay attention to it.The following calculation about IGBT driver output supplied for your reference.

The switching characteristic of IGBT are determined by inner and external resistance of gate charge.Figure 1 shows the gate capacitance distrubtion of IGBT,C_GE for Gate-Emmitter capacitor,C_CE for Collector-Emitter capacitor ,C_GC for Gate-Collector capacitor or Miller Capacitor.Gate input capacitance be shown by C_ies C_GE and C_GC ,it is the important value for calculating the output power of IGBT driver .The capacitor was not affected by the temperature but closely related with the voltage of Gate-Emitter .The capacitance value by IGBT datasheet is not uesful in actual application because it was get from the bridge.In testing circuit,the voltage added to the collector always are 25V (some factorys adjust it for 10V).In this case,the measuring capacitor are bigger than V_CE=600V(Figure 2).As the gate measuring voltage rather than the threshold voltage is low(V_GE=0V ), the Miller effect are not included in and the actual gate capacitance are much bigger than the capacitance, the capacitance C_ies by IGBT datasheet are just being for reference

The determination of the IGBT gate charge:
Gate charge ( IGBT gate total charges under the gate voltage difference )is most important for designing a driver .We can do the following calculation with it.

Gate Drive Energy   E = Q_G • U_GE = Q_G • [ V_G(on) - V_G(off) ]

Gate Drive Power   P_G = E • f_SW = Q_G • [ V_G(on) - V_G(off) ] • f_SW

Total Driver Power   P = P_G + P_S(the power consumption of driver)

Average Output Current   I_outAV = P_G / ΔU_GE = Q_G • f_SW

Maximal Switching Frequency  f_{SW max.} = I_outAV(mA) / Q_G(μC)

Peak Current  I_{G MAX} = ΔU_GE / R_{G min} = [ V_G(on) - V_G(off) ] / R_{G min}

f_{sw max.} : Maximal switching frequency
I_outAV : Average current of signal-channel
Q_G : IGBT gate total charges under gate voltage difference
R_{G extern} : The external gate resistance of IGBT
R_{G intern} : Internal gate resistance of IGBT chip

In fact in many cases, we can't find the gate charge in datasheet and there is also no description about it in the rising process of gate voltage.You should test the turn-on energy E to calculate Q_G according to the method by IEC 60747-9-200 - Semiconductor
devices - Discrete devices - Part 9: Insulated-gate bipolar transistors (IGBTs).

E = ∫I_G • ΔU_GE • dt = Q_G • ΔU_GE

The method is simple but complicated ,actually we can calculate gate charge C_ies with the value of input capatiance by the IGBT datasheet :
If the C_ie by the IGBT datasheet is V_CE = 25 V, V_GE = 0 V, f= 1 MHz，then we can get   
C_in=4.5C_ies，

Gate charge Q_G ≈ ΔU_GE • C_ies • 4.5 = [ V_G(on) - V_G(off) ] • C_ies • 4.5
C_ies :The input capacitance of IGBT(C_ies can be found in IGBT dataheet)

If the Cie by the IGBT datasheet is V_CE = 10 V, V_GE = 0 V, f= 1 MHz，then we can get     C_in=2.2C_ies，

Gate charge Q_G ≈ ΔU_GE • C_ies • 2.2 = [ V_G(on) - V_G(off) ] • C_ies • 2.2
C_ies :The input capacitance of IGBT(Cies can be found in IGBT dataheet)

If the gate charge curve in positive quadrant being given in IGBT datasheet, then the negative quadrant caculated by the Cies will be more accurate.

Gate charge Q_G ≈ Q_G(on) + ΔU_GE • C_ies • 4.5 = Q_G(on) + [ 0 - V_G(off) ] • C_ies • 4.5
The condition for C_ies: V_CE = 25 V, V_GE = 0 V, f= 1

Gate charge Q_G ≈ Q_G(on) + ΔU_GE • C_ies • 2.2 = Q_G(on) + [ 0 - V_G(off) ] • C_ies • 2.2
The condition for C_ies: V_CE = 10 V, V_GE = 0 V, f= 1

When choosing IGBT driver for all applications , the following shoule be taken into consideration:
•The maximal output gate capacitance should be enough for gate charge and discharge to IGBT.
•The output peak current I_outPEAK of the driver should be bigger than or equal to maxium peak current.
•The maximal output gate capacitance should be enough for gate charge and discharge to IGBT.
The maxium output charge per pulse given in POWER-SEM datasheet should be taken into consideration while selecting the driver.
In addition,the isolation voltage V_{isol IO} and dv/dt also should be considered

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