US Patent 9209787 Semiconductor device controllers

We describe a controller (130) for controlling a power semiconductor switching device (132) into a selected one of a plurality of states, the states including a fully-off state, a saturated-on state, and at least one intermediate state. The switching device controller includes a voltage sense input (142) to sense a voltage on the device; a current sense input (current feedback) to sense a current passing through the device; a negative feedback control circuit (138) coupled to the sense inputs, a control output (136) to provide to the power semiconductor switching device a drive signal with a response dependent on one or more adjustable parameters; and a circuit controller (140) to control the adjustable parameters responsive to state command data, to control the switching device into a selected state, in particular by controlling an effective resistance of the device. Preferred intermediate states include an active low current state and an active low voltage state.