Discharge of an ac capacitor using totem-pole power factor correction (pfc) circuitry

A circuit, comprising:

• a first capacitor having first and second electrodes respectively coupled to first and second power supply input nodes;
• a first switching transistor having a conduction path coupled between the first power supply input node and a first DC node;
• a second switching transistor having a conduction path coupled between the first power supply input node and a second DC node;
• a first thyristor having a conduction path coupled between the second power supply input node and the first DC node;
• a second thyristor having a conduction path coupled between the second power supply input node and the second DC node;
• a first resistor and a third thyristor having a conduction path coupled in series between the second power supply input node and the first DC node;
• a second resistor and a fourth thyristor having a conduction path coupled in series between the second power supply input node and the second DC node;
• and
• a control circuit configured to sense a disconnection of input power to the first and second power supply input nodes and in response thereto turn on one of the first and second switching transistors and one of the third and fourth thyristors to discharge the first capacitor through one of the first and second resistors coupled in series with said one of the third and fourth thyristors.