Line-powered, phase-control circuit

Claim 1

A line-powered power supply circuit, comprising: a source of an AC, mains supply voltage; an inductance; a rectifier coupled to said mains source for rectifying said mains supply voltage to develop a rectified supply voltage in said inductance without significant low pass filtering with respect to a frequency of said mains supply voltage; a switching transistor operating at a switching frequency that is higher than that of said main supply voltage coupled in series with said inductance for generating current pulses in said inductance having magnitudes that vary significantly during a period of said mains supply voltage in a manner to increase a power factor associated with said mains source; a charging capacitor; a first diode coupled to said charging capacitor and to a junction terminal between said inductance and said transistor for coupling a charging current to said capacitor that is produced in said inductance from said current pulses; a transformer having a primary winding that is coupled to said charging capacitor and to said transistor to form a switch mode power supply operating in a flyback manner; and a second diode coupled to said junction terminal and to said transistor and poled to conduct in a direction of a main current path in said transistor for coupling said transistor to said inductance to generate said current pulses and for decoupling said inductance from said primary winding when said charging current is coupled to said capacitor.