LED Driver Current Modulation for Imperceptible Gamma Flicker
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Solution Overview
Problem
Conventional LED drivers using Gamma strobes cause discomfort due to perceivable flickering, limiting exposure time in phototherapy and daily use.
Innovation Solution
An LED driver with a strobe circuit and DC-DC converter generates a low-frequency modulation signal, providing an adjustable operating current with a DC and low-frequency AC signal, limiting the current ripple factor to less than 8%, ensuring the flicker is imperceptible.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Gamma strobe is used for phototherapy, then therapeutic effect is improved, but user comfort deteriorates due to perceivable flickering
Solution Approach 1:
The patent changes the current waveform parameters by superimposing a sinusoidal AC signal on the DC driving current, creating a smooth oscillating current that produces Gamma band flicker (25-100 Hz) while maintaining low ripple factor (<8%). This parameter transformation allows the light to produce therapeutic flicker effects without the harsh perceivable flickering of conventional square-wave dimming, thus improving therapeutic effect while reducing flicker perception.
2Device complexity
If conventional LED driver is used, then device simplicity is maintained, but flicker perception increases causing user discomfort
Solution Approach 1:
The patent introduces a current source circuit as an intermediary component between the LED driver and LED light source. This current source circuit generates the sinusoidal AC signal and superimposes it on the DC driving current, acting as a mediator that transforms the conventional square-wave current into a smooth oscillating current. This intermediary structure reduces flicker perception while maintaining relatively simple device architecture.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution reduces flicker perception, allowing prolonged exposure for effective phototherapy and enabling round-the-clock use without discomfort.
Implementation Method 1
The strobe circuit is configured to generate a low-frequency modulation signal. The DC-DC converter is coupled to the strobe circuit and is configured to provide an adjustable operating current to the LED light source according to a DC signal and the low-frequency modulation signal.
Implementation Method 2
The DC-DC converter is coupled to the strobe circuit and is configured to provide an adjustable operating current to the LED light source according to a DC signal and the low-frequency modulation signal.
Implementation Method 3
an LED driver, an LED lighting system and an operating method thereof in order to overcome the drawbacks of conventional technologies
Data Source
AI summary
An LED driver, an LED lighting system and an operating method thereof are provided. The LED driver is for driving an LED light source and includes a strobe circuit and a DC-DC converter. The strobe circuit generates a low-frequency modulation signal. The DC-DC converter is coupled to the strobe circuit and is configured to provide an adjustable operating current to the LED light source according to a DC signal and the low-frequency modulation signal. The operating current includes a DC current signal and a low-frequency AC current signal corresponding to the DC signal and the low-frequency modulation signal respectively. A frequency of the low-frequency AC current signal is between 25 Hz and 100 Hz, and a current ripple factor, equaling a difference of a maximum value and a minimum value of the operating current divided by a sum of the maximum value and the minimum value, is less than 8%.