CHARGING AN INPUT CAPACITOR OF A LOAD CONTROL DEVICE

摘要

A load control device for control ling the amount of power delivered to an electrical load (1904) may include a rectifier circuit (1920) configured to receive a phase-control voltage and produce a rectified voltage (VRECT). A power converter (1930) may be configured to receive the rectified voltage (VRECT) at an input and generate a bus voltage (VBUS). An input capacitor (CIN) may be coupled across the input of the power converter (1930). The input capacitor (CIN) may be adapted to charge when the magnitude of the phase control voltage is approximately zero volts. The power converter (1930) may be configured to operate in a boost mode, such that the magnitude of the bus voltage (VBUS) is greater than a peak magnitude of the input voltage. The power converter may be configured to operate in a buck mode to charge the input capacitor (CIN) from the bus voltage (VBUS) when the magnitude of the phase-control voltage is approximately zero volts.