ACTIVE DISCHARGER FOR HIGH VOLTAGE CAPACITORS WITH REDUCED IDLE POWER LOSS

An active capacitor discharging circuit for a power supply can include a current source adapted to be coupled between one or more capacitors and ground; and a voltage-controlled switch that selectively opens responsive to the power supply operating to reduce power consumed by the current source and selectively closes responsive to the power supply not-operating to allow the current source to discharge the one or more capacitors. The current source can include a depletion mode MOSFET coupled to a source resistance such that a channel of the depletion mode MOSFET is in series with the source resistance and a distal terminal of the source resistance is coupled to a gate of the depletion mode MOSFET. The voltage-controlled switch can include a P-channel JFET in series with the current source.