Patent ID: 9013161
Filing Date: 2015-04-21
Classification: G01R,H02H,H02M,H03K

Abstract:
1. A load drive circuit for use with a power supply to drive a load connected to an output terminal of the load drive circuit, the load drive circuit comprising: a switching element, connected between a positive electrode of the DC power supply and the output terminal, for carrying out a switching operation and thereby driving the load; a constant current circuit connected in parallel with the switching element; a resistor connected between the constant current circuit and a negative electrode of the DC power supply; an open load detection circuit that detects that the load is open if the voltage at the output terminal is higher than of a first threshold voltage and lower than the value of a second threshold voltage subtracted from the voltage of the DC power supply when the switching element is in an off-state; and a supply fault detection circuit that detects a failure of the DC power supply to supply power to the load if the voltage at the output terminal is higher than the value of the second threshold voltage subtracted from the voltage of the DC power supply when the switching element is in an off-state.