A current pulse generator circuit that is monolithically integrated into a single semiconductor die and configured to provide a high pulsing frequency. The first GaN FET transistor controls charging of the capacitor in the boost converter. The second GaN FET transistor controls the discharge of the capacitor through a load such as a laser diode connected to the boost converter. The two GaN FET transistors are preferably enhancement mode GaN FETs and can be integrated into a single semiconductor die with gate drivers. The diode of a typical boost converter circuit can also be implemented as a GaN FET transistor in the present invention, and can also be integrated into a single semiconductor die.