Load drive circuit

Abstract

The invention relates to a load drive circuit wherein an emergency shutdown switch for forcible interruption and a normal shutdown switch for normal current control are disposed in series in a load power supply circuit. An emergency shutdown switch (SW.sub.A) and a normal shutdown switch (SW.sub.B) are disposed in series in a load power supply circuit. The normal shutdown switch (SW.sub.B) is periodically driven off for a short time by means of a control signal (X) from a normal shutdown switch control circuit (30), and the fact that this is off is monitored by an output signal (AC) from a monitoring circuit (40). If the output signal (AC) is not generated for an off-delay time or more of an off-delay circuit (21), then a control signal (Z) for an emergency shutdown switch control circuit (20) is stopped thereby forcibly switching off the emergency shutdown switch (SW.sub.A).

Dependencies are inferred from the claim text.