| 摘要 |
PCT No. PCT/JP93/00048 Sec. 371 Date Sep. 2, 1993 Sec. 102(e) Date Sep. 2, 1993 PCT Filed Jan. 14, 1993 PCT Pub. No. WO93/14506 PCT Pub. Date Jul. 22, 1993.This invention relates to a load driving circuit having a fail-safe breaking mechanism for breaking a primary power source when a failure occurs. This invention also relates to a load driving circuit capable of saving electricity in driving an inductive load and reducing a delay in stopping the load. The breaking mechanism for breaking the primary power source has no contact. The load driving circuit includes a power supply circuit involving a semiconductor switching element that turns ON and OFF the supply of power to the load. There is arranged a detector for detecting a failure in the semiconductor switching element. When detecting a failure, the detector provides an output signal to activate the breaking mechanism. To drive the inductive load, the power supply circuit may have two power supply sources. In response to a load driving instruction signal, the two power supply sources together apply a high voltage to the load. After a predetermined period, one of the power supply sources is stopped, and during a steady-state operation of the load, the remaining power source applies a low voltage to the load. The load driving instruction signal may be used to provide a pulse width modulated output, which is used to supply power to the load through a transformer. During a steady-state operation of the load, this arrangement supplies a voltage lower than an operation start voltage to the load, to thereby reduce power consumption and a delay in stopping the load.
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