Method and apparatus for implementing a power converter input terminal voltage discharge circuit

A circuit, comprising:

• a control circuit coupled to an input of a power converter, the control circuit coupled to sense whether an electrical energy source is coupled across input terminals of the input of the power converter;
• and
• a switch coupled to the control circuit and coupled to the input terminals of the input of the power converter, the control circuit coupled to drive the switch to have a high average impedance when the electrical energy source is coupled across the input terminals of the input of the power converter, the control circuit coupled to drive the switch to discharge a capacitance coupled between input terminals of the input of the power converter to below a threshold voltage in less than a maximum period of time from when the electrical power source is uncoupled from the input terminals of the input of the power converter.

A circuit, comprising:

• a control circuit coupled to an input of a power converter, the control circuit coupled to sense whether an ac voltage source is coupled across input terminals of the input of the power converter;
• and
• a switch coupled to the control circuit and coupled to the input terminals of the input of the power converter, the control circuit coupled to drive the switch in a high average impedance when the ac voltage source is across the input terminals of the input of the power converter, the control circuit coupled to drive the switch to discharge a capacitance coupled between input terminals of the input of the power converter to below a threshold voltage in less than a maximum period of time from when the ac voltage source is uncoupled from the input terminals of the input of the power converter, wherein the control circuit and the switch are included in a integrated circuit.

A discharge circuit, comprising:

• a first capacitance that is coupled to be charged in response to an electrical energy source being coupled to an input of a power converter, wherein the first capacitance is coupled to be discharged when the electrical energy source is uncoupled from the input of the power converter;
• and
• a switch coupled to a second capacitance coupled to the input of the power converter, wherein the first capacitance is coupled to drive the switch in a first operating mode in response to the electrical energy source being coupled to the input of the power converter, wherein the first capacitance is coupled to drive the switch in a second operating mode in response to the electrical energy source being uncoupled from the input of the power converter, wherein the second capacitance is not discharged through the switch in response to the switch being driven in the first operating mode, wherein the second capacitance is discharged through the switch to a threshold voltage in less than a maximum period of time in response to the switch being driven in the second operating mode, and wherein the control circuit is coupled to drive the switch to have a high average impedance in the first operating mode.