A circuit is provided for converting alternating current power into direct current (DC) power and providing a digitally stable ground for operation of a processor-based device. Embodiments of the circuit include a transformer isolating (e.g., via galvanic isolation) a primary side from a secondary side of the circuit. A controller (e.g., a pulse width modulation (PWM) controller) on the primary side directs a switching circuit to selectively permit current flow through a primary side of the transformer to a first ground node on the primary side. A secondary winding of the transformer sources a rectified DC output relative to a second ground node that is isolated from the first ground node. In some cases, compensation on the secondary winding side provides isolated feedback to the controller via an optical isolator or some other circuit. The controller directs the switching circuit based at least in part on the error correction feedback and input from an auxiliary winding of the transformer.