High efficiency turn-off loss reduction network with active discharge of

Abstract

A turn-off loss reduction network is applied to the power transistors of a double-ended inverter circuit to reduce power dissipation therein. A switched resonance discharge circuit is utilized to discharge the storage capacitor of the turn-off loss reduction network. Dissipation during discharge is eliminated by including an energy recovery circuit in the discharge network which is operative to return the energy to the input voltage source of the inverter. The gate discharge circuit includes a gated resonant discharge path with an inductive storage medium having a secondary winding or otherwise coupled to return the energy to the input voltage source. At the beginning of the conduction cycle of the power switching transistor, a gate is enabled which allows the capacitor to discharge into the inductive storage medium. When the discharge current reaches its peak value, the gate is disabled, and the energy stored in the inductive medium is discharged to the source by flyback action.