A DC-to-DC power regulator circuit, such as a synchronous buck DC-to-DC converter circuit, having improved efficiency. A power stage is provided, having an input port for receiving a DC input voltage and having an output port for providing a regulated DC output voltage. The power stage includes a control FET transistor having a first terminal, a second terminal, and a gate, the first terminal being connected to the input port. An energy storage element has a first terminal connected to the control FET output terminal and a second terminal connected to the output port. A driven FET transistor has a first terminal connected to ground, a second terminal connected to the first terminal of the energy storage element, and a gate. A driver circuit has an input adapted to receive a control signal, and provides first driver signal to the control FET gate and a second driver output signal to the driven FET gate. The driver circuit has a power supply node for receiving power to power the driver circuit, which is connected to a power supply external to the converter circuit. A driver powering circuit is arranged to derive power from the first terminal of the energy storage element and provide it to the power supply node of the driver circuit after an initial period of operation of the converter circuit.