OVERVOLTAGE PROTECTING CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide an overvoltage protecting circuit that can simplify a circuit. SOLUTION: This overvoltage protecting circuit is provided with a DC power supply 1; a load driving circuit 4 such as a DC-DC converter or a DC-AC inverter supplied with the DC power supply 1 through a contact piece 3 of a relay 2; a load such as a discharge lamp driven by the load driving circuit 4; a detecting circuit 6 for detecting the overvoltage of the load 5; and the relay 2 actuated when the detecting circuit 6 detects the overvoltage. When the relay 2 is actuated, the contact piece 3 cuts off the DC power supply 1 currently supplied to the load driving circuit 4, and the DC power supply 1 is switched to continue operating the relay 2 directly through a diode 7.