초록 ▼

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)

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).

대표청구항 ▼

[ We claim:] [1.] A load drive circuit comprising:an emergency shutdown switch;a normal shutdown switch; anda load power supply circuit,wherein the emergency shutdown switch and normal shutdown switch comprise a series circuit, and further wherein the series circuit is further connected in series wi

[ We claim:] [1.] A load drive circuit comprising:an emergency shutdown switch;a normal shutdown switch; anda load power supply circuit,wherein the emergency shutdown switch and normal shutdown switch comprise a series circuit, and further wherein the series circuit is further connected in series with the load power supply circuit,further wherein the emergency shutdown switch switches on simultaneously with generation of a load drive signal and switches off after a predetermined off-delay time from a termination of the load drive signal,further wherein the normal shutdown switch switches on after a predetermined on-delay time from the generation of said drive signal and switches off simultaneously with the termination of said drive signal, andfurther wherein monitoring means is provided for monitoring an ability of the normal shutdown switch to be switched off during load power supply.