Patent ID: 7629794
Filing Date: 2009-12-08
Classification: B60L,B60W,G01R,Y02T

Abstract:
1. A leakage detection circuit that detects an electric leakage between a power supply device and a conductor containing a higher-level device which is supplied with a direct-current power by the power supply device, the leakage detection circuit comprises: a branch, one end of which is connected to a negative electrode of the power supply device and another end of which to the conductor; the branch including a series-connected circuit having: a protective resistance that prevents an excessive electric current from flowing through the branch; a switch element that opens and closes the branch in response to a first control signal which transmits a detection timing; a current detection resistance that detects a current flowing through the branch; and a variable power voltage supplying unit that outputs a voltage for detecting leakage on a positive electrode side of the power supply device and a voltage for detecting leakage on a negative electrode side of the power supply device in response to a second control signal which selects the positive or negative electrode side, the leakage detection circuit further including: an amplifier that amplifies a voltage between both ends of the current detection resistance; and a computer that outputs the first and second control signals and determines a leakage current or a leakage resistance based on an output from the amplifier.