Method and apparatus to reduce the volume required for bulk capacitance in a power supply

摘要

A driver circuit included in a power supply having a rectifier coupled to a single phase AC input voltage is disclosed. An example driver circuit includes a drive signal generator to generate a drive signal to be coupled to a variable impedance element. A voltage sensor is coupled to the drive signal generator and is to be coupled to sense a voltage across a high voltage capacitance. The driver circuit is to be coupled to control the variable impedance element in response to the voltage sensor. A low voltage capacitance is allowed to receive current from the input if the sensed voltage is less than a second threshold value. The low voltage capacitance is prevented from receiving current from the input if the sensed voltage is greater than a first threshold value.