Hold-up circuit with safety discharge for preventing shut-down by momentary power interruption

摘要

A storage capacitor of a hold-up circuit is connected by a resistor to the current conducting bus supplying operating voltage to computer hardware from a power source. The capacitor is thereby charged to the operating voltage level in order to subsequently maintain computer operation by discharge through a diode during power interruption of a relatively long duration determined by the capacitor charge and a predetermined drop in voltage applied to the computer load causing its shutdown. Detection of such drop in voltage is operative through an opto-isolator to safely discharge the capacitor by relay controlled grounding thereof.