Patent ID: 7061733

Claim:
A power supply cut-off circuit for a power rectifier adapted to be connected to a power supply line leading to a load, comprising: a switching circuit adapted to be connected between the rectifier and the power supply line; a control circuit connected to the switching circuit, the control circuit including an operational amplifier having inputs connected across the switching circuit and a switching control element connected between an output of the operational amplifier and the switching circuit; and wherein, when the switching circuit has been connected between the rectifier and the power supply line, the control circuit is operable to disconnect the rectifier from the power supply line using the switching circuit when the control circuit senses that the rectifier has malfunctioned; and the operational amplifier is operable to apply a first signal indicative of a rectifier malfunction to the switching element that causes the switching control element to generate a second signal that causes the switching circuit to become nonconducting and disconnects the rectifier from the power supply line.