Control IC Synchronizes Modulator and Generator to Eliminate LED Flicker
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Solution Overview
Problem
Existing control methods for current sources used in lighting systems, such as those employing LEDs, suffer from unwanted fluctuations in light emission due to asynchronous operation of modulators and generators, leading to visible flickering and EMI mitigation issues.
Innovation Solution
A control IC that synchronizes the operation of a modulator and a generator by providing a pulse signal from the generator to the modulator, ensuring that the updates of the periodically changing signal and the control signal are coordinated, thereby eliminating asynchronous updates and their associated unwanted fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the modulator and generator operate asynchronously with independent update frequencies, then the system can independently optimize each component's performance, but unwanted fluctuations and visible flickering occur in the light emission
Solution Approach 1:
The patent merges the update timing of the modulator and generator by having the modulator update its periodically changing signal at the same moments when the generator updates the control signal. This synchronization ensures that both components operate in unison, eliminating the asynchronous fluctuations that cause visible flickering while maintaining the ability to independently optimize each component's operational parameters
Solution Approach 2:
The patent implements a feedback mechanism where the modulator's update timing is determined by the generator's operation timing. The modulator receives feedback about when the generator updates the control signal and synchronizes its own updates accordingly, ensuring that changes in the periodically changing signal are applied at moments that do not create unwanted light emission fluctuations
2Productivity
If the modulator updates the periodically changing signal at a different frequency than the generator updates the control signal, then each component can operate at its optimal frequency, but electromagnetic interference and unwanted fluctuations occur
Solution Approach 1:
The patent applies periodic action by updating the modulator's periodically changing signal at regular intervals that coincide with the generator's update moments. This creates a synchronized periodic operation pattern where both components update together at frequencies that are multiples or sub-multiples of a base frequency, eliminating electromagnetic interference caused by asynchronous updates while maintaining operational efficiency
3Illumination intensity
If the amplitude of the periodically changing signal changes continuously, then smooth light emission control is achieved, but EMI mitigation becomes difficult
Solution Approach 1:
The patent applies dynamics by making the amplitude of the periodically changing signal time-dependent and periodically varying. The amplitude changes dynamically over time according to a periodic pattern, creating smooth light emission control while the periodic nature of the amplitude modulation helps mitigate electromagnetic interference by distributing spectral energy across multiple frequencies rather than concentrating it at a single frequency
Data Source
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AI summary
The invention relates to control IC for controlling a current source configured to provide a current to lighting means optional at least one light emitting diode (LED). The control IC comprises a controller for controlling the current, a modulator for generating, based on an output of the controller, a periodically changing signal, wherein an amplitude of the signal periodically changes with a first frequency around an amplitude of the output of the controller, and a generator for generating, based on the periodically changing signal, a control signal for controlling the current source. The generator is configured to update the control signal according to a pulse signal having a second frequency greater than the first frequency. The generator is configure to provide the pulse signal to the modulator. The modulator is configured to update, based on the pulse signal, the amplitude of the signal so that the amplitude of the signal periodically changes in steps, with the first frequency, around the amplitude of the output of the controller.