Überbrückungsschaltung für Wechselstrom/Gleichstrom-Umwandler

摘要

Holdover circuitry for an off line switcher, including a DC to DC converter (120), maximizes holdover time, during source voltage (Vin) failures, by commutating (by 222) a precharged holdover capacitor (221) to the input of a power factor correcting preregulator (110). This limits the size of the holdover capacitor required without any loss in holdover time. Reduction in the size of the required holdover capacitor required for a desired holdover time improves volumetric efficiency of the off line switcher. This arrangement further improves efficiency of the DC-to-DC converter and decreases stress on its components by narrowing the input voltage range requirement.