Gate Driver Capacity Calculation

Gate Driver Capacity Calculation

　2018年05月15日

Selection of CONCEPT IGBT Gate Driver Core

- Selection of IGBT driver by use of IGBT datasheet
- For example: IGBT driver for Infineon IGBT module FF450R17KE4

Calculation of Gate Driver Power

Gate drive power
- P_Gate = Q_G * f_sw * ΔV

Use of C_GE<
     - Additional power by use of optional C_GE
     - P_Cge = C_GE * f_sw * ΔV²

Total driver output power
     - P = P_Gate + P_cge

Example with FF450R17ME4
     - Gate charge 4.6 μC
     - No C_GE
     - Switching frequency 4 kHz
     - P = 4.6 μC * 4 kHz * 25 V
     - P = 0.46W

Calculation of Gate Current

Minimum gate resistor
     - R_min = R_{G min} + R_Internal
     - Most of IGBT have embedded chip resistance

Peak output curent
     - I_max = 0.74 .ΔV /( R_{G min} + R_Internal )

Example with FF450R17ME4
     - P = P_Gate + P_cge
     - R_Gmin = 3.3Ω
     - R_Internal = 1.7Ω
     - ΔV = 25V
     - I_max = 0.74*25V / 5 Ω
     - I_max = 3.7A

    The theoretically derived reduction factor of 0.74 for I_max (non-osc) is further reduced in real applications by the limited driver switching speed, the transmission line nature of real gate loops, and the internal time constants of the driver's blocking capacitors.

Gate Driver Selection

Values for example with FF450R17ME4
     - Blocking Voltage 1700V
     - Gate drive power P = 0.46W
     - Gate current ± I_max = 3.7A

Driver selection
     - https://gate-driver.power.com/
     - Home >> Products >> Product Finder
     - Driver core