Drive circuit

A PWM DC to AC inverter that outputs mains frequency power comprising a plurality of voltage controlled switching devices, each having a control terminal with an associated input capacitance and two or more other terminals, where one or more of the voltage controlled switching devices is driven by a drive circuit comprising:

• a full bridge switching circuit comprising a positive supply terminal, a negative supply terminal, a first output terminal, and a second output terminal, the positive supply terminal and negative supply terminal for receiving a DC supply voltage,
• a transformer with a primary winding and a secondary winding, the primary winding comprising a first end coupled to the first output terminal of the full bridge switching circuit and a second end coupled to the second output terminal of the full bridge switching circuit,
• a transition selection circuit coupled to the secondary winding of the transformer and also coupled to a control terminal of a respective voltage controlled switching device of the inverter, the transition selection circuit having at least two active devices adapted to conduct current between the secondary winding and the control terminal of the respective voltage controlled switching device for controlling charge and discharge of the input capacitance of the respective voltage controlled switching device, and
• at least one inductance that forms a single series resonant circuit with the input capacitance of the control terminal,
• wherein the full bridge switching circuit can be operated to generate drive pulses via the selection circuit that propagate into and resonate in the single series resonant circuit to generate a resonated output during both charge and discharge that is fed to the input terminal to operate the respective voltage controlled switching device.