Switching circuit, gate driver and method of operating a transistor device

A multi-level gate driver for a Group III nitride-based enhancement mode transistor device comprising a source, a gate and a drain,

• wherein during an on-cycle of the Group III nitride-based enhancement mode transistor device, the multi-level gate driver is configured to:
• supply the gate with a first gate voltage during a first time period so that a first gate current Ig1 is applied during the first time period that is sufficient to turn on the gate and maintain the gate in an on-state;
• and
• supply the gate with a second gate voltage during a second time period subsequent to the first time period so that a second gate current Ig2 is applied to the gate during the second time period to maintain the gate in an on state, wherein Ig1>5Ig2, or Ig1>10Ig2, or
• wherein during an on-cycle of the Group III nitride-based enhancement mode transistor device the multi-level gate driver is configured to:
• supply the gate with a first gate current Ig1 during a first time period, wherein Ig1 is sufficient to turn on the gate and maintain the gate in an on-state;
• and
• supply the gate with a second gate current Ig2 during a second time period subsequent to the first time period, wherein Ig2 maintains the gate in an on state, wherein Ig1>5Ig2, or Ig1>10Ig2.