Voltage transient protection circuit for MOSFET power transistors

Claim 1

A voltage transient protection circuit for a pair of metal oxide semiconductor field effect transistors (MOSFETs) operated in a push-pull circuit with said MOSFETs each having a drain connection, a source connection, and a gate connection, including: a transformer having a tapped primary winding and a pair or primary end windings; a first of said pair of end windings connected to a first of said drain connections, and a second of said pair of end windings connected to a second of said drain connections; a pair of diodes with each of said diodes connected to a separate transformer end winding with said diodes further connected in common to a first end of an energy dissipation means; said energy dissipation means having a second end connected to said transformer tapped winding; said energy dissipation means including a parallel combination of a capacitor and a resistor; said transformer tapped winding further connected by circuit means to a source of potential for said MOSFETs and with said source of potential further including a circuit ground; second energy dissipation means having inductive means in parallel with a parallel connected diode means; said second energy dissipation means connecting said tapped primary winding to said source of potential; and both of said MOSFETs source connections being connected to said circuit ground; said diodes and said energy dissipation means limiting voltage transients in said protection circuit to a level that is not harmful to said MOSFETs.