Patent ID: 7098631

Claim:
A power factor correcting converter comprising: an input configured to be connected to an input voltage source; an output configured to be connected to an output circuit including at least one filter capacitor and a load; a control circuit; at least one inductor; at least one power switch being turned on and off by the control circuit so that the input voltage source is connected across the at least across one inductor when the power switch is on; at least one rectifier that connects the at least one inductor between the input voltage source and the output circuit so inductor current flows out from the input voltage source and into the output circuit when the power switch is off, the control circuit modulating on and off intervals of the power switch so a momentary input current at the input of the converter is directly proportional to both a momentary value of an input voltage at the input of the converter and to a momentary value of a current of the load, the control circuit comprising: a SR flip-flop that in a set state turns the power switch on; an integrator; a clock generator that produces a fixed frequency train of narrow pulses for resetting the flip-flop and the integrator, a saw tooth voltage generated by the integrator by integrating a signal proportional to the current of the load, the integrator being reset by the pulses from the clock generator so an amplitude of the saw tooth voltage is proportional to the current of the load and inversely proportional to the frequency of the clock pulses; and a comparator that compares the saw tooth voltage to a signal proportional to a current delivered to the output circuit, the comparator setting the SR flip-flop when a value of the current delivered to the output circuit drops below a value of the saw tooth voltage.