The ISO5452 device 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 the gate with respect to the emitter. This prevents the IGBT from unintentionally turning on because of current induced from the collector to the gate because Miller effect. In this condition connecting the CLAMP output of the gate driver to the IGBT gate is not necessary, but connecting the CLAMP output of the gate driver to the IGBT gate is also not an issue. Typical values of V_CC2 and V_EE2 for bipolar operation are 15 V and –8 V with respect to GND2.

For operation with unipolar supply, typically, V_CC2 is connected to 15 V with respect to GND2, and V_EE2 is connected to GND2. In this use case, the IGBT can turn on because of additional charge from IGBT Miller capacitance caused by a high-voltage slew-rate transition on the IGBT collector. To prevent IGBT from turning 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 and the CLAMP current output is activated.