Patent ID: 7944653
Filing Date: 2011-05-17
Classification: H02H

Abstract:
1. A self fault-detection circuit for a ground fault circuit interrupter having a line input with a phase terminal and a neutral terminal, and a load output with a phase terminal and a neutral terminal, comprising: (i) a Metal Oxide Varistor (MOV) fault detection unit configured for detecting a fault condition of the MOV, and sending a first trigger signal if a fault condition of the MOV is detected; (ii) a trip circuit fault detection unit configured for detecting a fault condition of a trip circuit, and sending a second trigger signal if a fault condition of the trip circuit is detected, wherein the trip circuit comprises: (iii) a fault reaction unit for receiving the first trigger signal from the MOV fault detection unit and the second trigger signal from the trip circuit fault detection unit, and responding to the first and the second trigger signals with an action; wherein the MOV fault detection unit comprises: wherein the trip circuit fault detection unit comprises: wherein, in operation, when the trip circuit is working under a predetermined working condition and the square wave signal generator generates simulated square wave ground fault signal, a voltage difference is generated across the fifth resistor of the first branch of the trip circuit status electrical current path, indicating said predetermined working condition; and wherein, in operation, when at least one of the first and the second trigger signals is received by the fault reaction unit, the fault reaction unit indicates that at least one fault exist in the ground fault circuit interrupter.