Guoxing Wang

US Patent:

20090195943, Aug 6, 2009

Filed:

Jan 31, 2008

Appl. No.:

12/023111

Inventors:

Song Liu - Cupertino CA, US
Ramesh Prakash - Campbell CA, US
Guoxing Wang - Santa Clarita CA, US

International Classification:

H02H 9/04

US Classification:

361 56

Abstract:

An overvoltage protection circuit includes a shunt circuit adapted for connection to at least one circuit node to be protected from an overvoltage condition and a voltage generator coupled to the shunt circuit. The shunt circuit is selectively activated as a function of a control signal supplied to the shunt circuit. The voltage generator is operative to generate the control signal for activating the shunt circuit during the overvoltage condition. The control signal has a level which varies in a manner that at least partially changes offsets in activation threshold of the shunt circuit.