A switching power supply includes power factor correction circuitry and a standby output converter. One or more loads may be coupled to one or more outputs of the switching power supply. The switching power supply is configured to disable the power factor correction circuitry under some load conditions and to enable the power factor correction circuitry under other load conditions. As a consequence, power that would have been drawn by the power factor correction circuitry is conserved when the power factor correction circuitry is disabled.