Abstract: An external defibrillator high voltage circuit with a leakage prevention circuit. The high voltage circuit includes first and second output terminals configured for electrical interconnection to electrodes, first and second charge supply terminals configured for interconnection to a charging voltage supply, and a plurality of capacitors. Charging semiconductor switches which are responsive to charge control signals electrically interconnect the capacitors to the charge supply terminals in a parallel circuit to charge the capacitors. Discharging semiconductor switches which are responsive to discharge control signals electrically interconnect the capacitors in a series circuit between the output terminals to generate defibrillation pulses. The discharging switches include at least two switches interconnected to each other at a leakage shunting node and in a series circuit between one of the capacitors and the second output terminal.