Patent ID: 9717123
Date: 2017-07-25
CPC Classifications: H05B

Claim:
1. A method in a light-emitting diode (LED) controller for generating control signals for driving multiple LED channels implementing LED dimming function using pulse width modulation (PWM), the method comprising: driving a plurality of LED channels using a plurality of PWM signals to turn on and off the LED channels within a switching cycle at a PWM frequency, each LED channel being driven by a respective PWM signal; each of the PWM signals having a leading edge for asserting the PWM signal to turn on the respective LED channel and a trailing edge for deasserting the PWM signal to turn off the respective LED channel; receiving a dimmer signal having a value indicative of a duty cycle for turning on the plurality of LED channels; generating a first PWM signal being switched at the PWM frequency for driving a first LED channel, the first PWM signal having the leading edge being a fixed signal transition at a first time location and the trailing edge being a signal transition being modulated to generate the first PWM signal having the duty cycle in response to the dimmer signal; and generating a second PWM signal being switched at the PWM frequency for driving a second LED channel, the second PWM signal having the leading edge being a signal transition being modulated to generate the second PWM signal having the duty cycle in response to the dimmer signal and a trailing edge being a fixed signal transition at the first time location.