Dimmable LED Driver Using Threshold-Based Switching Control
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Solution Overview
Problem
Existing LED dimming technologies require complex circuits and multiple components to achieve variable electric current, making them unreliable and costly for mass production, and they struggle to adapt to various driver configurations.
Innovation Solution
A driver device with a switched-mode power supply and a switch driver circuit that responds to voltage thresholds to generate control pulses of variable amplitude and duty cycle, allowing for feedback-controlled variable electric current to semiconductor light-emitting devices, using a control pulse formatter to combine PWM and analog control signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If complex circuits and multiple components are used to achieve variable electric current, then dimming control capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines PWM dimming and analog dimming control capabilities into a single switched-mode power supply circuit. The control input accepts both PWM signals and analog voltage signals, merging two separate dimming functions into one unified circuit architecture, thereby reducing overall system complexity while maintaining versatile dimming control.
Solution Approach 2:
The switched-mode power supply control input is designed to accept multiple types of control signals (PWM and analog voltage) through a universal interface. The control circuit automatically adapts to the input signal type, making the circuit multi-functional and capable of supporting different dimming methods without requiring separate dedicated circuits for each method.
2Measurement precision
If multiple components and complex circuits are used, then dimming precision is improved, but reliability decreases
Solution Approach 1:
The patent implements a feedback control mechanism where the switched-mode power supply continuously monitors its output current and adjusts its operation accordingly. The control circuit compares the actual output with the desired output (from PWM or analog input) and makes real-time corrections, ensuring precise dimming control while simplifying the overall circuit architecture through intelligent control rather than complex passive components.
3Adaptability or versatility
If complex circuits are used for hybrid dimming, then dimming control flexibility is improved, but ease of manufacture decreases
Solution Approach 1:
The patent achieves different dimming modes (PWM and analog) by changing the parameters of the control input signal rather than using different circuit configurations. The control circuit detects the signal type and adjusts its internal operation parameters accordingly, allowing flexible dimming control while maintaining a single, simple circuit design that is easy to manufacture using standard switched-mode power supply topology.
Data Source
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AI summary
A driver device provides variable electric current to at least one semiconductor light-emitting device. It comprises a switched-mode power supply with a current switch for generating an output current of the driver device, and a switch driver circuit (202) to provide switching pulses to said current switch (201) at a switching frequency. The switch driver circuit (202) responds to voltages exceeding a first threshold at a control input (EN/DIM) by enabling the providing of switching pulses. It responds to voltages between said first threshold and a second, further threshold by allowing an amplitude of a measured current to reach a value proportional to the voltage at the control input. A control pulse formatter (203) provides the control input (EN/DIM) with control pulses of variable amplitude exceeding said first threshold at a pulse width modulation frequency smaller than said switching frequency.