A DC-DC converter operates outside of an audible frequency range under light current load conditions with reduced switching frequency by reducing supply current and regulating output voltage. A control for the converter maintains the switching frequency above an audible frequency range and reduces supply current by modulating switch on-time, sinking supply current, or permitting negative supply current values. The output voltage of the converter is regulated by modulating switch on-time, clamping output voltage, or modifying feedback detector thresholds. The power converter operates with improved efficiency under light current load conditions, while avoiding operation in an audible frequency range to prevent the generation of audible noise in converter components.