AC to DC conversion system with current spreading circuit

Claim 1

A current spreading circuit comprising; input circuit means for receiving an input AC voltage and rectifying said AC voltage, output circuit means for providing a DC output voltage, and pulse-width-modulation means intercoupled between said input circuit means and said output circuit means and comprising means adapted to pass input AC current in pulse width increments with the pulse width varying in inverse proportion to the AC voltage, whereby when the instantaneous AC voltage is low the pulse widths are wider and when the voltage is high the pulse widths are narrower, said pulse-width-modulation means comprising a pulse-width-modulation (PWM) generator having feedback means responsive to output voltage, electronic switch means and drive circuit means coupled from said PWM generator to said switch means for controlling conduction of said switch means, said drive circuit means including a base drive transformer, said electronic switch means comprising a pair of transistors, said pulse-width-modulation means further comprising a transformer coupled from said transistors to said output circuit means, said transformer having a pair of primary windings and a secondary winding, said output circuit means including an output bridge and an inductor-capacitor circuit with the capacitor functioning as a storage capacitor, and a second inductor-capacitor circuit at the output of said means for rectifying.