Patent ID: 7564706

Claim:
A single-phase power factor correcting ac-dc converter having an input for receiving a full-wave rectified ac input voltage and an input current, an output for putting out a dc output voltage, and a common return, comprising a main power path in a series connection from the input to the output comprising an input inductor, a boost switch, a first buck switch, and an output inductor, and a storage energy path in a series connection from a connection of the input inductor with the boost switch to a connection of the first buck switch with the output inductor comprising a boost rectifier, and a second buck switch, there also being a buffer capacitor connected from a connection of the boost switch with the first buck switch to the common return, a storage capacitor for storing energy connected from a connection of the boost rectifier with the second buck switch to the common return, a catch rectifier switch connected from the connection of the first buck switch with the output inductor to the common return, and an output filter capacitor connected from the output to the common return, the single-phase power factor correcting ac-dc converter further having at least a first mode of operation for when the full wave rectified ac voltage is below its rms voltage, and a second mode of operation for when the full wave rectified ac voltage is above its rms voltage, the first mode of operation comprising: the boost switch is on, the boost rectifier is reverse-biased, the first buck switch controls by pulse width modulation the input current for power factor correction, the second buck switch controls by pulse width modulation the output dc voltage, and the catch rectifier conducts a current of the output inductor when the first and second buck switches are off, and the second mode of operation comprising: the first buck switch is on, the second buck switch is off the boost switch controls by pulse width modulation the output dc voltage, and the boost rectifier is forward biased when the boost switch is off.