Bi-directional Switch AC-to-DC Converter for LED Arrays
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing AC-to-DC converters for LED applications are impractical due to their size and cost, particularly as operating voltages increase, as they require larger passive components like capacitors and inductors, making them unsuitable for all LED applications.
Innovation Solution
A single-stage power conversion topology using a pair of bi-directional switches and control circuits to efficiently convert AC to DC, with a snubber filter to manage voltage spikes, allowing for compact and cost-effective operation across a wide range of voltages and frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If known converters use passive components such as capacitors and inductors, then they can convert AC to DC, but the size and cost increase as operating voltages increase
Solution Approach 1:
The patent removes traditional passive filtering components (capacitors and inductors) from the AC-to-DC converter circuit. Instead of using these passive elements for rectification and filtering, the invention employs active switching devices (MOSFETs Q1-Q4) controlled by synchronous rectification logic to achieve voltage conversion without the bulky passive components that would otherwise be required to handle high operating voltages.
Solution Approach 2:
The patent replaces the traditional passive component-based electromagnetic conversion mechanism with an active electronic switching mechanism. The MOSFETs and control circuits substitute for the mechanical/electromagnetic action of large capacitors and inductors, using controlled semiconductor switching to achieve the same AC-to-DC conversion function with dramatically reduced size and cost.
2Power
If known converters use passive components such as capacitors and inductors, then they can convert AC to DC, but the cost increases as operating voltages increase
Solution Approach 1:
The patent removes traditional passive filtering components (capacitors and inductors) from the AC-to-DC converter circuit. Instead of using these passive elements for rectification and filtering, the invention employs active switching devices (MOSFETs Q1-Q4) controlled by synchronous rectification logic to achieve voltage conversion without the bulky passive components that would otherwise be required to handle high operating voltages.
Solution Approach 2:
The patent uses inexpensive semiconductor MOSFETs (Q1-Q4) and simple control logic instead of expensive high-voltage passive components. The active switching devices are much cheaper than the high-voltage capacitors and inductors that would be required in traditional designs, making the converter cost-effective even at high operating voltages.
3Power
If traditional AC-to-DC conversion is used, then power can be converted, but power factor is poor and line current distortion is high
Solution Approach 1:
The patent implements synchronous rectification control where the switching of MOSFETs Q1-Q4 is synchronized with the input AC voltage waveform. The control circuitry (68, 70) monitors the AC input and generates gate drive signals that switch the MOSFETs in sync with the voltage waveform, creating a feedback-controlled system that maintains unity power factor and minimizes current distortion by ensuring current draw is in phase with voltage.
Solution Approach 2:
The patent employs periodic switching of the MOSFETs synchronized to the AC line frequency. The switching devices are turned on and off in periodic cycles that match the sinusoidal input waveform, creating a controlled periodic action that draws current in a sinusoidal pattern in phase with the voltage, thereby eliminating power factor issues and current distortion associated with traditional uncontrolled rectification.
Data Source
AI summary
Disclosed herein is a power converter circuit for a LED lighting device. The power converter includes a pair of input terminals adapted to be connected to a signal source, at least one LED, a first circuit adapted to supply current to the at least one LED and including: a first bi-directional switch connected between one input terminal and one side of the at least one LED, and a second bi-directional switch connected between the other side of the at least one LED and the other input terminal, and a second circuit adapted to supply current to the at least one LED and including: a third bi-directional switch connected between the other input terminal and the one side of the at least one LED, and a fourth bi-directional switch connected between the one input terminal and the other side of the at least one LED.