Patent ID: 7646153
Filing Date: 2010-01-12
Classification: H02M,H05B

Abstract:
1. A switching regulator control circuit, comprising: a feedback signal terminal for inputting thereinto a feedback signal produced in response to a current flowing through a load, where the load comprises a LED; a reference voltage circuit configured to output one of a plurality of discrete reference voltages based on a control signal, where each discrete reference voltage corresponds to one of a plurality of different luminance stages of the LED; an error amplifying circuit for inputting thereinto the feedback signal and the one of the plurality of discrete reference voltages to amplify a difference therebetween; a triangular wave oscillating circuit for oscillating a triangular wave; and a comparator for comparing an output signal of the error amplifying circuit with the triangular wave to output a switching signal, wherein the reference voltage circuit is further configured to switch between the plurality of discrete reference voltages based upon the control signal to output a switched reference voltage.