A GaN half bridge circuit is disclosed. The circuit includes a bootstrap power supply voltage generator is configured to supply a first power voltage and includes a switch node. The circuit also includes a bootstrap transistor, a bootstrap transistor drive circuit, and a bootstrap capacitor connected to the switch node and to the bootstrap transistor. The bootstrap capacitor is configured to supply the first power voltage while the voltage at the switch node is equal to the second switch node voltage, the bootstrap transistor is configured to electrically connect the bootstrap capacitor to a power node at a second power voltage while the voltage at the switch node is equal to the first switch node voltage, and the bootstrap power supply voltage generator does not include a separate diode in parallel with the drain and source of the bootstrap transistor.