Primary-side regulation of output current in a line-powered LED driver

Abstract

A line-powered LED driver is operable to provide primary-side regulation of output current supplied to LED circuitry. The circuit includes a feedback loop coupled to a power converter, wherein the feedback loop adds scaled input current to scaled input voltage to produce a control signal. The power converter is responsive to the control signal to adjust input current drawn by the power converter in response to changes in line voltage to provide constant input power. The power converter produces output power for supplying constant output current at the LEDs. The feedback loop may use a reference voltage derived from the LED circuitry so that the output power may be regulated to provide constant LED current for varying LED voltages. When compared to secondary-side current feedback schemes, the LED driver provides increased efficiency and reliability at a reduced cost by implementing primary-side regulation of the output current.

Dependencies are inferred from the claim text.