Triac Dimmer Circuit for LED Color Temperature Adjustment
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Solution Overview
Problem
Existing dimmers, such as triac dimmers, cannot adjust color temperature in lighting applications, requiring additional circuits and microcontrollers, leading to increased system costs and complexity.
Innovation Solution
A dimming circuit that generates current reference signals to adjust the ratio of load currents in LED driving circuits, allowing for color temperature adjustment without the need for a microcontroller, using a triac dimmer, linear regulation circuits, and switching circuits to control load currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a triac dimmer is used to adjust input voltage, then light brightness can be adjusted, but color temperature cannot be adjusted
Solution Approach 1:
The patent segments the control of multiple LED loads by generating separate current reference signals for each load type (cold-color and warm-color LEDs). The reference signal generating circuit divides the dimming signal into multiple independent current references, allowing separate control of each LED string's current, thereby enabling independent adjustment of color temperatures while maintaining brightness control.
2Adaptability or versatility
If an MCU and communication module are added to adjust color temperature, then color temperature adjustment is achieved, but system cost increases
Solution Approach 1:
The patent extracts and removes the MCU and communication module from the system, replacing them with a dedicated reference signal generating circuit. This circuit directly processes the dimming signal to generate appropriate current references for each LED load, eliminating the need for complex microcontroller-based control and communication infrastructure while maintaining color temperature adjustment functionality.
Solution Approach 2:
The patent replaces expensive, complex components (MCU, communication modules) with a simpler, more cost-effective reference signal generating circuit. This circuit uses basic electronic components to achieve the same control function, significantly reducing system cost and complexity while maintaining the required adaptability for color temperature adjustment.
3Adaptability or versatility
If multiple loads are controlled in parallel, then color temperature adjustment is possible, but the system cannot simultaneously control brightness and color temperature
Solution Approach 1:
The patent implements feedback mechanisms where the reference signal generating circuit continuously monitors the dimming signal and adjusts the current reference signals for each LED load accordingly. This feedback loop ensures that as the overall brightness is adjusted, the color temperature can be independently controlled by modifying the distribution of current references to different LED strings, enabling simultaneous control of both parameters.
Data Source
AI summary
There is provided a dimming circuit, a dimming method and a LED driving circuit. On the basis of the dimming of a dimmer, the circuit according to the disclosure generates a plurality of current reference signals corresponding to a plurality of loads in accordance with a dimming signal, to change a ratio of load currents of the plurality of loads, so that, the adjustment of color temperature is implemented, wherein the dimming signal represents the changes of switching operation or dimming speed of the dimmer, and the ratio of current load currents of the plurality of loads is latched or a predetermined ratio of load currents is latched. According to the disclosure, the dimmer can be used for directly adjusting color temperature, without the need for a MCU, so that, the system compatibility is improved and the cost is decreased.