LED controllers, drivers and lighting circuits
AssigneeNXP B.V.
InventorMichael Scott
Life of this patent
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Abstract
A controller for controlling a plurality of LED lighting strings is disclosed, the controller comprising, for each of the plurality of LED lighting strings: a frequency modulator configured to modulate a baseline frequency to generate a time-vary modulated frequency, wherein the frequency modulator is configured to modulate the baseline frequency by a jitter superposed on a regular repeating pattern which varies more slowly than the jitter, to result in the modulated frequency; and a modulated PWM signal generator configured to generate a modulated PWM signal having the modulated frequency and a predetermined duty cycle; wherein the regular repeating patterns for the PWM signals are spaced apart in phase. Associated drivers, LED lighting circuits and methods are also disclosed.
Claims15
A controller for controlling a plurality of LED lighting strings,
- the controller comprising, for each of the plurality of LED lighting strings:
- a frequency modulator configured to modulate a baseline frequency to generate a time-varying modulated frequency,
- wherein the frequency modulator is configured to modulate the baseline frequency by a jitter superposed on a regular repeating pattern which varies more slowly than the jitter, to result in the modulated frequency;
- and
- a modulated PWM signal generator configured to generate a modulated PWM signal having the modulated frequency and a predetermined duty cycle;
- wherein the regular repeating patterns for the PWM signals are spaced apart in phase.
A method of controlling a plurality of LED lighting strings,
- the method comprising, for each of the plurality of LED lighting strings:
- modulating a baseline frequency to generate a time-vary modulated frequency,
- wherein the baseline frequency is modulated by a jitter superposed on a regular repeating pattern which varies more slowly than the jitter, to result in the modulated frequency;
- and generating a modulated PWM signal having the modulated frequency and a predetermined duty cycle;
- wherein the regular repeating patterns for the PWM signals are spaced apart in phase.
Dependencies are inferred from the claim text.