Phase Controlled Dimming LED Driver Without Microprocessor
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Solution Overview
Problem
Conventional LED dimming systems face challenges with TRIAC instability and the need for processing units, limiting deep dimming capabilities and color mixing in LED lighting applications.
Innovation Solution
A phase-controlled dimming LED driver circuitry that receives a regulated AC signal, decodes the phase to set the dimming level, and uses pulse width modulation (PWM) to control the light intensity without a microprocessor, allowing for deep dimming down to 0.1% of full light intensity and stable TRIAC operation, while enabling independent control of multiple LED drivers for color mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a microprocessor is used to control LED dimming, then precise control of light intensity is achieved, but device complexity increases
Solution Approach 1:
The patent extracts and removes the microprocessor from the LED dimming control system, replacing it with an analog circuit implementation. The phase detection and PWM generation functions that were previously performed by software in a microprocessor are now implemented using discrete analog components including phase detectors, oscillators, and comparator circuits, thereby eliminating the need for complex digital processing while maintaining control precision.
Solution Approach 2:
The patent replaces the digital/electronic microprocessor-based control system with an analog electronic control system. The microprocessor's digital signal processing is substituted with analog phase detection circuits and continuous voltage comparison mechanisms, transitioning from discrete digital control to continuous analog control, which simplifies the overall device architecture.
2Illumination intensity
If TRIAC dimming is used for LED control, then deep dimming capability is achieved, but TRIAC instability occurs
Solution Approach 1:
The patent implements preliminary action by detecting the phase angle of the AC waveform before the TRIAC is triggered, and using this detected phase information to pre-calculate and set the appropriate PWM duty cycle. This pre-synchronization ensures that the TRIAC is always triggered at the correct point in the AC cycle, preventing instability caused by improper phase timing while enabling deep dimming through precise PWM control.
Solution Approach 2:
The patent employs feedback mechanisms where the actual TRIAC trigger timing and LED current are continuously monitored. The phase detector compares the AC line voltage phase with the TRIAC trigger signal, and any phase deviation is fed back to adjust the trigger timing. This closed-loop feedback ensures stable TRIAC operation across varying load conditions while maintaining deep dimming capability.
3Illumination intensity
If phase control dimming is used, then light intensity adjustment is achieved, but harmonic distortion increases
Solution Approach 1:
The patent uses periodic PWM action synchronized with the AC line frequency to control LED brightness. Instead of using traditional phase-cutting methods that create significant harmonics, the system employs high-frequency periodic PWM switching that is modulated according to the detected AC phase. This periodic PWM approach transfers the dimming function to a higher frequency domain, significantly reducing harmonic distortion at the fundamental AC frequency while maintaining effective light intensity control.
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
Enables stable and deep dimming of LED lights without the need for processing units, maintaining constant voltage, and allowing for multicolor light generation by independently controlling separate LED drivers, thus overcoming TRIAC instability and enhancing dimming capabilities.
Implementation Method 1
a flyback converter stage configured to receive said rectified DC voltage signal from said input stage and to generate a regulated DC voltage on a constant voltage capacitor
Data Source
AI summary
The present invention relates to providing an improved phase controlled dimming LED driver circuitry, system and a method thereof, which is configured to enable dimming intensity of light generated by a light source, said phase controlled dimming driver circuitry being connected to a phase control dimmer that provides to it a regulated alternating current (AC) signal, wherein said phase controlled dimming driver circuitry does not include a microprocessor and pulse width modulates its output current, provided to said light source, at a frequency unrelated to the AC signal frequency. Further, the phase controlled dimming driver circuitry applies amplitude modulation (AM) and pulse width modulation (PWM) substantially simultaneously to the output current provided to the light source.