LED Driver Control Circuit for Compact Power Supply Design
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Solution Overview
Problem
Conventional LED power supply devices require larger substrate sizes due to the need for electrical insulation between LED arrays, leading to increased device size, as a significant potential difference occurs between the cathode ends of LED arrays when one array is lit and the other is not.
Innovation Solution
The power supply device incorporates a control circuit that adjusts currents through LED driver circuits, ensuring a voltage lower than the threshold voltage is applied to the target light source when current is prohibited, reducing the potential difference and allowing for closer conduction paths, thus minimizing device size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional LED power supply devices are used with two LED arrays alternately lit, then color temperature adjustment is achieved, but a large potential difference occurs between cathode ends requiring increased substrate size for electrical insulation
Solution Approach 1:
The patent applies equipotentiality by connecting the cathode ends of both LED arrays to a common reference potential through the control circuit. When one LED array is off, the control circuit maintains its cathode at the same potential as the active array's cathode, eliminating the potential difference that would otherwise require electrical insulation spacing. This allows the conduction paths to be placed closer together on the substrate.
2Reliability
If conduction paths are spaced out to ensure electrical insulation, then electrical insulation is maintained, but the substrate size increases
Solution Approach 1:
By maintaining equipotential conditions at the cathode ends through active control, the patent eliminates the need for large insulation spacing. The control circuit dynamically adjusts the potential of the inactive LED array's cathode to match the active array's cathode potential, allowing conduction paths to be positioned close together while maintaining electrical insulation reliability.
3Adaptability or versatility
If current is prohibited from flowing through one LED array, then color temperature control is achieved, but a large potential difference occurs requiring larger device size
Solution Approach 1:
The control circuit implements equipotentiality by actively maintaining the cathode potential of the inactive LED array equal to the cathode potential of the active LED array. This is achieved through the control circuit's ability to detect and equalize potential differences, allowing the inactive array to be turned off for color temperature control without creating the large potential differences that would otherwise increase device dimensions.
Data Source
AI summary
A power supply device includes LED driver circuits electrically connected to LED light sources, respectively, and a control circuit. Each of the LED light sources includes light-emitting diodes electrically connected in series. The control circuit is configured, when current is prohibited from flowing through a target light source, to perform control of a target driver circuit so that a voltage lower than a threshold voltage at which current starts to flow through the target light source is applied across the target light source. The target light source is a part of the LED light sources. The target driver circuit includes an LED driver circuit, corresponding to the target light source, of the LED driver circuits.