Abstract: A buck voltage converter comprising a high side switch, a low side switch, a capacitor, an inductor, a gate driver circuit having outputs coupled to the gate terminal of the high side switch and the gate terminal of the low side switch, and a separate voltage regulator circuit that powers circuitry internal to the buck voltage converter. The voltage regulator circuit includes a multiplexer having a first multiplexer input coupled to the input voltage source, a second multiplexer input coupled to the buck output of the buck voltage converter, and one or more multiplexer control inputs to select which of the two multiplexer inputs is coupled to a multiplexer output and pass transistor having a first terminal coupled to the multiplexer output of the multiplexer and having a second terminal coupled to the regulator output of the voltage regulator.