On embodiment pertains to an apparatus including a control loop configured to receive an output voltage sense signal. The control loop includes a compensator; a PWM signal generator coupled to an output of the compensator; a reference circuit configured to receive a tracking signal, and which is configured to low bandwidth low pass filter the tracking signal when the tracking signal amplitude becomes substantially constant and representative of an output voltage that is substantially non-zero, and an error amplifier having a first input coupled to an output of the reference circuit, a second input configured to receive the output voltage sense signal, and an output coupled to the compensator.