A device and method that includes a shunt regulator of a universal serial bus (USB) compatible power supply device is disclosed. The shunt regulator includes an amplifier with an output, a first input, and a second input. The shunt regulator also includes a current digital-to-analog converter (DAC) that is coupled to the first input of the amplifier and a voltage bus node. The current DAC adjusts a sink or a source current delivered at the first input of the amplifier to regulate a programmable output voltage (Vbus) in the USB-compatible power supply device. The current delivered by the DAC is responsive to receipt of a digital code indicative of a programmable power supply command specifying the Vbus to be delivered by the USB-compatible power supply device on the voltage bus node.