LED Jitter Compensation Circuit for Dimmer Flicker
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Solution Overview
Problem
Conventional LED lamps experience low-frequency jittering and flickering when used with dimmer switches designed for incandescent lamps, due to asymmetrical electrical characteristics, leading to inconsistent light intensity.
Innovation Solution
An LED controller with a jitter detection circuit and compensation circuit that adjusts the control signal to regulate current delivery, disabling current during longer cycles or half-cycles to compensate for phase angle variations, ensuring consistent light output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If phase angle control is used to dim LED lamps, then dimming capability is achieved, but low-frequency jittering and flickering occur due to asymmetrical electrical characteristics
Solution Approach 1:
The patent measures the phase angle of the input voltage signal before generating the dimming control signal. By preliminarily detecting the phase angle and calculating the expected jitter amount based on this measurement, the system proactively compensates for asymmetrical electrical characteristics before they cause visible flickering, thereby maintaining stable light output while preserving dimming capability
Solution Approach 2:
The patent implements a feedback mechanism where the phase angle of the input voltage signal is continuously measured and used to adjust the dimming control signal. The controller calculates the jitter amount based on the measured phase angle and modifies the PWM duty cycle accordingly, creating a closed-loop system that compensates for asymmetrical characteristics and eliminates low-frequency flickering
2Adaptability or versatility
If conventional dimmer switches are used with LED lamps, then compatibility with existing infrastructure is maintained, but inconsistent light intensity and detectable flickering occur
Solution Approach 1:
The patent introduces an intermediary LED controller that sits between the conventional dimmer switch and the LED lamp. This controller measures the phase angle of the dimmer's output signal, calculates the expected jitter based on asymmetrical characteristics, and generates a compensated PWM signal. The intermediary device enables compatibility with conventional dimmer infrastructure while eliminating the inconsistent light intensity and flickering that would otherwise occur
Solution Approach 2:
The patent dynamically changes the PWM duty cycle parameter based on the measured phase angle of the input voltage signal. By adjusting the duty cycle to compensate for the calculated jitter amount, the system maintains consistent light intensity output while working with conventional dimmer switches, effectively transforming the problematic phase-angle-controlled signal into a stable LED drive signal
Data Source
AI summary
An LED controller reduces jitter of an LED lamp. In one embodiment, the LED controller includes a jitter detection circuit adapted to determine an amount of jitter in an input voltage signal. The input voltage signal includes a plurality of cycles and indicates an amount of dimming for the LED lamp. The LED controller further includes a jitter compensation circuit, which generates a control signal to control regulated in the LED lamp such that an output light intensity of the LED lamp substantially corresponds to the amount of dimming for the LED lamp. The control signal controls current delivery to the LED lamp to compensate for the determined amount of jitter in the input voltage signal.