Patent ID: 9722599
Date: 2017-08-01
CPC Classifications: H03K

Claim:
1. A circuit comprising: a first switching transistor comprising a first source coupled to a first reference voltage terminal; a second switching transistor comprising a second source coupled to a first drain of the first switching transistor, and a second drain configured to be coupled to a transformer; a first diode coupled between the first drain of the first switching transistor and a first input terminal, wherein the first diode is configured to clamp a voltage of the first drain of the first switching transistor to a voltage of the first input terminal; and a switching circuit coupled between the second switching transistor and the first input terminal, wherein the switching circuit is configured to connect the second source of the second switching transistor to a second gate of the second switching transistor when a voltage of the second source of the second switching transistor exceeds the voltage of the first input terminal.