| 摘要 |
<p>PURPOSE:To prevent a voltage of less than a fixed value from being applying across a load, by discharging a capacitor in parallel to the load when the holding voltage across the capacitor decreases blow a fixed value. CONSTITUTION:Alternating-current power supply 1, after being rectified 2 and smoothed 3, is applied to load 11 such as a microcomputer by way of constant-voltage circuit 4 and capacitor 8. If power supply 1 is broken momently for period TS, monitor voltage VD across capacitor 8 falls down to threshold level VT. Here, voltage comparator circuit 15 operates to send a command of a momentary stop process to the load and then outputs a signal voltage to delay pulse generating circuit 16. Although this voltage is applied to circuit 16 with delay of fixed time behind at the point in time when it is inputted to circuit 16, this is selecred within the fixed time to prevent load 11 from malfunctioning and getting out of control, and holding voltage across capacitor 8 is discharged nearly at a time by way of diode 13, resistance 14 and Tr12, thereby preventing the voltage from being applied across load 11.</p> |
