A system comprising a central or sub-controller (110, 120) and a plurality of semiconductor switching device controllers, the central or sub-controller to control a plurality of semiconductor switching devices in synchronism by sending a command to the plurality of semiconductor switching devices all to move to a defined, intermediate state, before proceeding to send out a command for a next state change, each said semiconductor switching device controller for controlling one of said semiconductor switching devices into a selected one of a plurality of states, the states including a fully-off state, a saturated-on state, and at least one said intermediate state between said fully-off state and said saturated-on state, said semiconductor switching devices each having first and second input/output terminals and a control terminal, each of the switching device controllers comprising: an interface to receive device command data and defining a commanded said state for the respective switching device; a voltage sense input to sense a voltage on one of said input/output terminals of said switching device; a current sense input to sense a current passing through said semiconductor switching device via said input/output terminals; a control output to provide a drive signal to said control terminal of said switching device; a feedback control circuit coupled to said voltage sense input, to said current sense input and to said control output, to provide said drive signal responsive to said sensed voltage and sensed current, wherein said feedback control circuit has one or more adjustable parameters, and wherein said a response of said drive signal to said sensed voltage and sensed current is dependent on said one or more adjustable parameters; and a circuit controller coupled to said interface and to said feedback control circuit, wherein said circuit controller is configured to control said one or more adjustable parameters (α,β) responsive to said command data; and wherein a state of said one or more adjustable parameters determines a state of said switching device set by said drive signal from said feedback control circuit, and wherein said commanded states define states of said one or more adjustable parameters for said circuit controller to control said semiconductor switching device into said fully-off state, said saturated-on state, and said at least one intermediate state. an interface to receive device command data and defining a commanded said state for the respective switching device; a voltage sense input to sense a voltage on one of said input/output terminals of said switching device; a current sense input to sense a current passing through said semiconductor switching device via said input/output terminals; a control output to provide a drive signal to said control terminal of said switching device; a feedback control circuit coupled to said voltage sense input, to said current sense input and to said control output, to provide said drive signal responsive to said sensed voltage and sensed current, wherein said feedback control circuit has one or more adjustable parameters, and wherein said a response of said drive signal to said sensed voltage and sensed current is dependent on said one or more adjustable parameters; and a circuit controller coupled to said interface and to said feedback control circuit, wherein said circuit controller is configured to control said one or more adjustable parameters (α,β) responsive to said command data; and wherein a state of said one or more adjustable parameters determines a state of said switching device set by said drive signal from said feedback control circuit, and wherein said commanded states define states of said one or more adjustable parameters for said circuit controller to control said semiconductor switching device into said fully-off state, said saturated-on state, and said at least one intermediate state.