| 摘要 |
<p>PURPOSE:To provide a capacitor discharging circuit capable of sufficiently securing prescribed initial set time even when an instantaneous interruption or the like is generated and a timing generating circuit using the discharging circuit. CONSTITUTION:The electrostatic charge of a capacitor C is charged/discharged by turning on/off a switch SW connected to the capacitor C in parallel and the volage change of the charging/discharging is compared with a reference voltage Vr by a comparator 12 to generate a timing signal. In the timing generating circuit, a photo-MOS relay PMR indicating low resistance when an input current Id inputted from a power supply Vcc is lower than a prescribed current and allowed to be changed to high resistance when a current higher than the prescribed current flows connected in parallel with the capacitor C. By means of the PMR even if an instantaneous interruption is generated in the power supply Vcc when the switch SW is in an off state, the charge of the capacitor C is quickly discharged through the PMR, so that initialization can be completely executed.</p> |
