Center-Tapped LED Converter for Flexible Output Voltage
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Solution Overview
Problem
Existing LLC converter designs for LED loads are limited in variability of output voltage and configuration options, restricting the flexibility in connecting LED loads and providing suitable voltage ranges.
Innovation Solution
An isolated primary side switched converter with a galvanic isolation stage featuring a secondary side winding with a center tap and a rectification circuit that sets distinct electrical polarities for terminals, allowing for multiple voltage configurations to supply LED loads efficiently, including the use of a decoupling circuit to stabilize voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional LLC converter design with a standard secondary side winding is used, then the converter structure is simple, but the output voltage variability is limited
Solution Approach 1:
The secondary side winding is divided into multiple sections with a center tap, creating distinct voltage zones. This segmentation allows the rectification circuit to select different voltage levels by connecting to different terminals, thereby achieving multiple output voltages from a single winding structure.
Solution Approach 2:
The patent introduces a center tap dimension in the secondary side winding, transforming a single-terminal configuration into a multi-terminal configuration. This dimensional change in the electrical connection topology enables additional voltage selection points without requiring multiple separate windings.
2Adaptability or versatility
If multiple voltage configurations are implemented using additional windings, then the output voltage variability increases, but the device complexity increases
Solution Approach 1:
A single secondary side winding with center tap serves multiple functions by providing different voltage levels through its different terminals. The same physical winding structure supports multiple output configurations, eliminating the need for separate windings for different voltage levels.
Solution Approach 2:
Multiple voltage provision functions are merged into a single secondary side winding with center tap configuration. Instead of using separate windings for different voltages, the patent combines all voltage provisioning into one integrated winding structure with accessible taps.
3Adaptability or versatility
If a center tap configuration is used on the secondary side, then the voltage variability increases, but the rectification circuit complexity increases
Solution Approach 1:
The rectification circuit is designed to dynamically select different terminal connections based on the required output voltage. The circuit can switch between different terminal pairs (e.g., center tap to first terminal, center tap to second terminal) to provide different voltage levels to LED loads.
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
This solution enables the supply of LED loads with different voltages using the same secondary side of the converter, providing higher variability in output voltage and ensuring a steady DC supply, thus overcoming the limitations of traditional LLC designs.
Implementation Method 1
a galvanic isolation stage separating a primary side and a secondary side of the converter, a secondary side winding (107) of the isolation stage, wherein the secondary side winding is coupled to a primary side winding
Implementation Method 2
a rectification circuit on the secondary side of the converter, wherein the rectification circuit is configured to set the first terminal at a first electrical polarity, and to set the second and the third terminal at a second electrical polarity that is different to the first electrical polarity
Data Source
AI summary
An isolated primary side switched converter (100) has a galvanic isolation stage (105) separating a primary side (101) and a secondary side (103). The secondary side winding (107) is connected to a rectification circuit and has a center tap. A first terminal (T1), a second terminal (T2) and a third terminal (T3) are provided for connecting one or more LED loads (LED1, LED2) to the secondary side (103) of the converter (100). The rectification circuit (109) is configured to set the first terminal (T1) at a positive electrical polarity and to set the second terminal (T2) at a negative polarity. The third terminal (T3) is electrically connected to the center tap. One or two LED loads can be connected between T1 and T3 (low voltage) and T2 and T3 (low voltage), or in one embodiment a single LED load can also be connected between T1 and T2 (high voltage).