ZHCSDT1D june 2015 – may 2023 ISO5451
PRODUCTION DATA
The ISO5451 supports both bipolar and unipolar power supply with active Miller clamp.
For operation with bipolar supplies, the IGBT is turned off with a negative voltage on its gate with respect to its emitter. This prevents the IGBT from unintentionally turning on because of current induced from its collector to its gate due to Miller effect. In this condition it is not necessary to connect CLAMP output of the gate driver to the IGBT gate, but connecting CLAMP output of the gate driver to the IGBT gate is also not an issue. Typical values of VCC2 and VEE2 for bipolar operation are 15 V and -8 V with respect to GND2.
For operation with unipolar supply, typically, VCC2 is connected to 15 V with respect to GND2, and VEE2 is connected to GND2. In this use case, the IGBT can turn-on due to additional charge from IGBT Miller capacitance caused by a high voltage slew rate transition on the IGBT collector. To prevent IGBT to turn on, the CLAMP pin is connected to IGBT gate and Miller current is sinked through a low impedance CLAMP transistor.
Miller CLAMP is designed for miller current up to 2 A. When the IGBT is turned-off and the gate voltage transitions below 2 V the CLAMP current output is activated.