LED Dimming Circuit Dynamic Mode Switching
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Solution Overview
Problem
Conventional dimming circuits for LED lighting struggle with achieving high accuracy dimming and over-current protection, especially in applications requiring a wide dimming range, leading to complex structures and increased costs.
Innovation Solution
A dimming circuit that includes a power conversion unit, input voltage sampling, output voltage sampling, current sampling, dimming signal sampling, and a control unit to dynamically adjust the operating mode of the LED driving power based on output current thresholds, allowing operation in Continuous Conduction Mode, Discontinuous Conduction Mode, and Chopping Mode for expanded dimming range and over-current protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional dimming driving circuit is used, then the circuit structure is simple, but the dimming accuracy is insufficient and the dimming range is limited
Solution Approach 1:
The patent implements dynamic mode switching between CCM, DCM, and chopping modes based on real-time output current levels. The control unit automatically transitions between operating modes to optimize dimming accuracy across different current ranges, thereby achieving high precision dimming without requiring a permanently complex circuit structure.
Solution Approach 2:
The patent changes the operating parameters of the power conversion unit by switching between different conduction modes (CCM, DCM, chopping mode) depending on the output current level. This parameter change allows the circuit to achieve high dimming accuracy at low currents while maintaining simplicity at higher currents.
2Measurement precision
If the LED driving circuit operates only in DCM mode or chopping mode, then high dimming accuracy is achieved, but the circuit structure becomes complicated and costs increase due to additional over-current protection circuits
Solution Approach 1:
The patent dynamically selects the appropriate operating mode based on the output current level. When the current is high, CCM mode is used which inherently provides over-current protection. When the current is low, DCM or chopping modes are used for high precision dimming. This dynamic adaptation eliminates the need for separate over-current protection circuits.
Solution Approach 2:
The patent makes the power conversion unit capable of operating in multiple modes (CCM, DCM, chopping mode) depending on the application requirements. This multi-functionality allows the same circuit to achieve both high current delivery and high precision dimming without requiring separate dedicated circuits for each function.
3Adaptability or versatility
If multiple channels of LED with different colors are used for deep dimming and color control, then the dimming range is expanded, but the circuit structure becomes complicated
Solution Approach 1:
The patent implements dynamic mode switching that adapts to different output current levels, enabling the circuit to handle a wide dimming range from very low to high currents. This dynamic adaptation allows a single channel to achieve deep dimming capabilities that would otherwise require multiple LED channels, thereby reducing circuit complexity.
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 enables high accuracy dimming across a wide range while conveniently realizing over-current protection, simplifying the circuit structure and reducing costs by dynamically controlling the LED driving power modes based on output current levels.
Implementation Method 1
The power conversion unit receives an input voltage from the input end, and converts the input voltage into an output voltage output from the output end by operation of the switch
Data Source
AI summary
A dimming control method and a dimming circuit are used to control the brightness of a LED. The dimming circuit includes a power conversion unit having an input end, an output end, an inductor, and a switch. When the dimming current signal is higher than or equal to a first current threshold, the switch is controlled such that the power conversion unit operates in a continuous Conduction mode or a boundary Conduction mode; when the dimming current signal is lower than the first current threshold, the switch is controlled such that the power conversion unit operates in a discontinuous Conduction mode; and when the dimming current signal is lower than a second current threshold, the switch is controlled such that the power conversion unit operates in a chopping control mode.