Patent ID: 9161402
Filing Date: 2015-10-13
Classification: H05B,Y02B

Abstract:
1. A light-emitting diode (LED) driver for driving an LED string, the LED driver comprising: an LED controller configured to generate a PWM signal; a first transistor to turn on or off responsive to the PWM signal, the first transistor in series with the LED string, wherein an LED current passes through the first transistor and the LED string when the first transistor is turned on; a second transistor in series with the LED string and the first transistor, wherein a first portion of the LED current passes through the second transistor when the first transistor is turned on; a programmable trimming circuit in parallel with the second transistor, the programmable trimming circuit configured to pass a trimming circuit current controlled by one or more trimming control signals, wherein the trimming circuit current comprises a second portion of the LED current.