LED Drive Circuit Voltage Regulation for High-Voltage Loads
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Solution Overview
Problem
Conventional LED drive circuits have a limited output voltage range, restricting their use with LED loads requiring higher voltages, leading to manufacturing inefficiencies and increased production costs due to the need for multiple transformer designs and potential control errors.
Innovation Solution
An LED drive circuit incorporating a rectifier, power conversion module, voltage regulator, photo coupler, and controller using PWM technology, which allows for a wider voltage range by generating a third drive voltage that does not exceed the maximum rating of the controller, enabling operation with various LED loads through voltage regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the transformer uses a fixed weight ratio (e.g., 1:2) between primary and secondary windings, then the voltage transformation is stable and simple, but the output voltage range is limited and cannot accommodate LED elements requiring higher voltages
Solution Approach 1:
The patent introduces a variable winding configuration where the secondary winding can be dynamically adjusted between different connection modes (series/parallel) to change the output voltage ratio. This allows the transformer to adapt its transformation ratio from 1:2 to 1:4 or other configurations based on the LED string requirements, resolving the contradiction between fixed simplicity and voltage range adaptability
Solution Approach 2:
The patent changes the electrical parameters of the transformer by modifying the winding connections. By changing the connection mode of secondary windings (series to parallel or vice versa), the output voltage and current parameters are adjusted to match different LED load requirements, enabling a single transformer to serve multiple voltage ranges
2Adaptability or versatility
If the PWM controller voltage increases to match higher LED element voltages, then the LED load can be driven at higher voltages, but the PWM controller exceeds its maximum voltage rating and stops controlling properly
Solution Approach 1:
The patent introduces an intermediary voltage regulation stage between the transformer output and the PWM controller input. This intermediary circuit (using voltage-regulating components) steps down the high voltage from the transformer to a level within the PWM controller's rating, allowing the controller to reliably regulate high-voltage LED strings without exceeding its voltage limits
Solution Approach 2:
The patent segments the voltage regulation function into two parts: the transformer handles the primary voltage transformation, while a separate voltage-regulating circuit handles the final adjustment to match LED requirements. This segmentation allows each component to operate within its optimal voltage range, maintaining reliability while achieving high output voltage capability
3Manufacturing precision
If different transformer weight ratios are used for different numbers of LED elements in series, then each LED configuration receives appropriate voltage, but manufacturing and management become more inconvenient and production cost increases
Solution Approach 1:
The patent designs a universal transformer with multi-functional winding configurations that can serve multiple LED voltage requirements. By incorporating adjustable secondary winding connections, a single transformer model can replace multiple specialized transformers, simplifying manufacturing inventory and assembly processes while maintaining precise voltage matching for different LED string configurations
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 provides a more versatile and cost-effective LED drive circuit capable of collaborating with a variety of LED loads, reducing manufacturing complexity and production costs while ensuring stable operation across different voltage requirements.
Implementation Method 1
a rectifier, electrically connected to the AC power supply, for rectifying and converting an AC voltage outputted from the AC power supply into a DC voltage
Implementation Method 2
a power conversion module, electrically connected to the rectifier and the LED load, for converting and outputting the DC voltage into a first drive voltage and a second drive voltage
Implementation Method 3
a voltage regulator, electrically connected to the power conversion module, for receiving and processing the second drive voltage with a voltage regulating process to generate a third drive voltage
Implementation Method 4
a photo coupler, electrically connected to connected to an input end of the LED load, for generating a feedback signal according to an output signal outputted from the input end
Implementation Method 5
The controller is electrically connected to the voltage regulator and the photo coupler for receiving the third drive voltage and generating a control signal according to the feedback signal. The control signal controls the power conversion module by using the pulse width modulation (PWM) technology.
Data Source
AI summary
An LED drive circuit applied between an LED load and an AC power supply is provided. The circuit includes a rectifier, a power conversion module, a voltage regulator, a photo coupler and a controller. The rectifier rectifies and converts an AC voltage outputted from the AC power supply into a DC voltage. The power conversion module converts the DC voltage into a first drive voltage and a second drive voltage. The first drive voltage drives the LED load. The voltage regulator receives and processes the second drive voltage with a voltage regulating process to generate a third drive voltage not exceeding a maximum voltage rating of the controller. The photo coupler generates a feedback signal according to a signal outputted from the LED load. The controller receives the third drive voltage and generates a control signal to control the power conversion module according to the feedback signal.