Single Stage Buck Boost LED Driver With Digital PFC Control
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Solution Overview
Problem
Existing LED drivers face challenges with wide input voltage ranges, high total harmonic distortion (THD), low power factor, and high output current ripple, which affect efficiency and reliability, particularly in single-stage buck-boost converters.
Innovation Solution
A single stage buck-boost type LED driver with output current regulation, a digital compensation block, and a parallel resonant LC filter, along with a power factor correction (PFC) control circuit, to achieve high power factor, low THD, and low output current ripple, using a transient voltage suppressor (TVS) and digital maximum switching frequency limiting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a two-stage solution (PFC + DC-DC converter) is used, then output LED current ripple may be controlled at a low magnitude, but efficiency decreases and reliability reduces due to more switching devices
Solution Approach 1:
The patent combines the PFC and DC-DC converter functions into a single integrated stage, eliminating the need for separate switching devices in each stage. This single-stage buck-boost converter performs both power factor correction and current regulation simultaneously, reducing component count while maintaining controlled output current ripple through unified control architecture.
Solution Approach 2:
The single-stage converter is designed to perform multiple functions: power factor correction, voltage regulation, and current ripple control. The unified circuit topology handles both PFC and DC-DC conversion tasks that traditionally required separate stages, improving reliability by reducing the number of switching devices while maintaining all necessary control functions.
2Manufacturing precision
If a two-stage solution (PFC + DC-DC converter) is used, then output LED current ripple may be controlled at a low magnitude, but efficiency decreases due to two stages
Solution Approach 1:
The patent merges PFC and DC-DC converter stages into one integrated circuit, eliminating the energy losses associated with two separate conversion stages. The single-stage buck-boost topology reduces cumulative efficiency degradation by performing both functions in one unified power conversion process, minimizing total energy loss while maintaining controlled output current ripple.
3Ease of operation
If the number of switching devices is increased, then power flow control is improved, but susceptibility to thermal, over current and over voltage damage increases
Solution Approach 1:
The patent reduces the number of semiconductor switches by combining PFC and DC-DC control into a single switching device within the unified buck-boost converter. This single switch performs both PFC and current regulation functions, minimizing exposure to thermal and electrical stress while maintaining effective power flow control through integrated control logic.
4Adaptability or versatility
If a wide input voltage range (100V-528V) is supported, then adaptability to different customers is improved, but circuit complexity increases
Solution Approach 1:
The single-stage buck-boost converter is designed with universal operation across a wide input voltage range (100V-528V). The unified control architecture automatically adapts to different input voltages without requiring additional circuitry or configuration, maintaining constant current output regulation regardless of input variations. This universal design achieves wide voltage support without proportionally increasing circuit complexity.
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 enhances efficiency, reduces electromagnetic interference, and improves reliability by minimizing output current ripple and THD, while maintaining a wide input voltage range of 100V to 528V.
Implementation Method 1
A ripple control circuit has a transient voltage suppressor (TVS) and a parallel resonant LC filter and is configured and disposed to receive DC current output by the single stage buck-boost type converter, take advantage of the high impedance at resonance, reduce the size of the resonant LC filter, improve efficiency, and minimize the output current ripple content
Data Source
AI summary
Technologies are described for a light emitting diode (LED) driver configured for powering LED(s) and having a wide input voltage range between about 100V and about 528V, high power factor, low total harmonic distortion (THD), and low output current ripple load. The LED driver has a single stage buck-boost type converter with output current regulation, an output current regulation circuit, a ripple control circuit having a transient voltage suppressor (TVS) and a parallel resonant LC filter, a power factor correction (PFC) control circuit having a digital compensation block, a PFC controller, and a gate drive IC.