Fraunhofer Institute for Reliability and Microintegration IZM
Miniaturized, zero-dead-time high-efficiency drivers for Si, SiC, and GaN applications
A new Fraunhofer IZM concept reveals new approaches for fast-switching power semiconductors with reduced switching losses by eliminating the effect of the freewheeling diodes.
The first step of the concept is to reduce the energy consumption of the driver by recovering the energy stored in the gate. This is achieved by moving from resistive to inductive gate current controls, which showed itself to be feasible approach.
Reduced power consumption enables the second step of the concept: By transferring energy to the high side via a 10pF capacitor at high frequency (70MHz), standby supply can be kept to a minimum.
As an additional feature, new means for eliminating dead time were investigated by coupling high and low side gate paths via a transformer. This was shown to be an effective option for reducing switch losses and significantly decreasing ringing effects.