Modifying duty cycles of PWM drive signals to compensate for LED driver mismatches in a multi-channel LED system

摘要

An LED (Light Emitting Diode) controller comprises a first LED driver to generate a first PWM (Pulse Width Modulation) drive signal to turn on or turn off, respectively, a first current through a first LED string. Additionally, the LED controller comprises a compensation circuit to generate the first PWM drive signal responsive to a first duty set signals. The first duty set signal is indicative of a first duty cycle set for the first PWM drive signal. The compensation circuit receives a first feedback signal indicative of the first current, generates a first error signal indicative of a difference between a first predetermined target value and the first feedback signal, and generates the first PWM drive signal to have the first duty cycle corresponding to the first duty set signal and further adjusted by the first error signal.

主权项

1. An LED (Light Emitting Diode) controller comprising:
a first LED driver to generate a first PWM (Pulse Width Modulation) drive signal to turn on or turn off a first current through a first LED string responsive to the first PWM drive signal; and a first compensation circuit to generate the first PWM drive signal responsive to a first duty set signal, the first duty set signal being a first predetermined target duty cycle set for the first PWM drive signal, the first compensation circuit comprising:
a first error determination circuit to receive a first feedback signal indicative of the first current and to generate a first error signal indicative of a difference between a first predetermined target value and the first feedback signal; anda first PWM signal generation circuit to generate the first PWM drive signal to have the first duty cycle corresponding to the first duty set signal adjusted by the first error signal.