Mains supply DC power=pack - uses single phase switching circuit so that reduced valve smoothing capacitor is only switched in when voltage support is required

摘要

The d.c. power pack reduces the size of smoothing capacitor connected across the rectifier output by switching it in only at that point in each supply cycle when the supply voltage falls below the required load voltage. The capacitor (5) across the rectifier (1) is blocked by a diode. A switching circuit (6), with voltage dependant elements, by-passes the diode and thus allows the capacitor to discharge into the load (4) to maintain its applied voltage. When the supply rises in the next half cycle the switch turns off and the capacitor recharges through the diode.