Power converter with controller for switching between primary and battery power sources

In a power supply, an apparatus for controlling the selection of a primary power source or a battery power source for powering a load, said apparatus comprising:

• means having an input connected to receive AC voltage from said primary power source for rectifying said AC voltage;
• first switch means for alternately connecting or disconnecting said rectifying means from an input of a boost power factor correction means in response to a first switch control signal, said boost power factor correction means for adjusting the power factor of a voltage received at its input in response to a boost control signal and producing at an output a regulated DC voltage;
• a battery power source comprising one or more batteries;
• second switch means for alternately connecting or disconnecting said battery power source from said boost power factor correction means in response to a second switch control signal;
• and
• control means, coupled to the first and second switch means and the boost power factor correction means, for comparing the magnitude of said regulated DC voltage to a first preselected reference and generating an output error signal indicative of the difference therebetween, for comparing the magnitude of the AC voltage from the primary power source to a second preselected reference and generating an input error signal indicative of the difference therebetween and for generating the first and second switch control signals in response to said error signals, whereby either said rectifying means or said battery power source is connected to said boost power factor correction means, and for generating said boost control signal.