Power circuit switching device having a passive protection circuit

A power circuit switching device comprising:

• two switching terminals;
• a high-voltage depletion mode transistor and a low-voltage enhancement mode transistor arranged in series between the two switching terminals, the avalanche voltage of the low-voltage transistor being lower than the avalanche voltage of the high-voltage transistor;
• a first terminal for receiving a switching signal, electrically connected via a driver circuit to a gate of the high-voltage transistor;
• a second terminal for receiving a control signal, electrically connected to the gate of the low-voltage transistor;
• a normally-on protection circuit electrically connected between the second terminal and the gate of the high-voltage transistor to keep the high-voltage transistor in an off-state when the driver circuit is not electrically powered;
• and
• a control device electrically connected to the first terminal and the second terminal for processing the control signal and selectively transmitting the switching signal.