Patent ID: 8922128
Filing Date: 2014-12-30
Classification: H02M,H05B,Y02B

Abstract:
1. A controlling circuit for a light-emitting diode (LED) driver having a transformer, said controlling circuit comprising: a) a sampling circuit configured to generate a sampling signal that indicates an output current signal of said LED driver at a primary side of said transformer; b) an on time sensing circuit configured to sense an on time of an output diode arranged at a secondary side of said transformer; c) a regulating signal generator configured to generate a regulating signal based on said sampling signal, a voltage reference that is directly proportional to an expected output current of said LED driver, and said on time of said output diode; and d) a pulse-width modulation (PWM) controller configured to generate a controlling signal to control operation of a switching device of said LED driver based on said regulating signal.