A method of operating a power supply including first and second power converters connected to a load and a power factor correction circuit connected to the power converters includes operating the power supply in a normal power mode such that: the first and second power converters and the power factor correction circuit are active, the first and second power converters each drive their respective load, and the power factor correction circuit performs power factor correction for each circuit formed by the first and second power converters and their respective load, and operating the power supply in an auxiliary power mode such that: both the first power converter and the power factor correction circuit are deactivated and the second power converter is active, the second power converter drives its load, and the second power converter performs power factor correction for a circuit formed between the second power converter and its load.