Patent ID: 6611111
Filing Date: 2003-08-26
Classification: H05B

Abstract:
A load drive circuit comprising:a power supply; a load circuit; a load power supply switch configured to switch states between on and off, the load power supply switch being disposed on a downstream side of the power supply of the load circuit; a controller configured to drive the load circuit by supplying a load driving control signal and to monitor the state of the load power supply switch by supplying a monitoring control signal; a switching device connected to the load circuit for supplying a power supply voltage to the load circuit according to the load driving control signal; a monitoring switch circuits configured to monitor the state of the load power supply switch and to switch states between on and off based on the duration of the monitoring control signal; and a monitoring resistor connected to the monitoring switch circuit, wherein the controller is configured to switch the state of the load circuit between on and off based on a voltage value of the monitoring resistor, and wherein the controller is configured to supply the load driving control signal to the switching device for a duration sufficiently shorter than the duration of the monitoring control signal supplied to the monitoring switch circuit.