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DIMMING LED CIRCUIT AUGMENTING DC/DC CONTROLLER INTEGRATED CIRCUIT

United States Patent Application

20180035500
A1
View the Complete Application at the US Patent & Trademark Office
Embodiments include systems, methods, and apparatuses for providing a dimming function in a single stage AC input light emitting diode (LED) driver with a controller that contains an on-chip error amplifier and an on-chip fixed reference voltage source coupled to a first input of the error amplifier. The controller controls a duty cycle of a switching transistor to cause a feedback voltage, applied to a first package input terminal, to match the reference voltage. To achieve a dimming function, a voltage across a current sense resistor in series with the LEDs is applied to a first input of a high gain differential amplifier, and a variable dimming control voltage is applied to a second input of the differential amplifier. The output of the differential amplifier is coupled to the first package input terminal. The differential amplifier input signals will be matched at the target LED current level.
Song, Zhihua (San Jose, CA), Soer, Wouter (San Jose, CA), Bonne, Ron (San Jose, CA), Qiu, Yifeng (San Jose, CA)
Lumileds LLC (San Jose CA)
15/ 606,388
May 26, 2017
GOVERNMENT LICENSE RIGHTS [0002] This invention was made with U.S. Government support under Contract No. DE-EE0006703 awarded by the Department of Energy (DOE). The Government has certain rights in this invention.