Non-Isolated RCC LED Driver with Valley-Filling Circuit
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Solution Overview
Problem
Existing LED driver circuits, particularly those using ringing choke converters, suffer from low power factor and inefficient conversion, making them unsuitable for effective LED constant-current driving and energy utilization.
Innovation Solution
The proposed LED driver circuit incorporates a rectifier-filter circuit, a valley-filling circuit, and a non-isolated RCC circuit to adjust current waveforms and improve power factor, along with EMI filtering and protection mechanisms, enhancing conversion efficiency and constant-current accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an RCC circuit with isolation structure is used, then cost is reduced, but conversion efficiency cannot exceed 80%
Solution Approach 1:
The patent removes the isolation structure from the RCC circuit, transforming it from an isolated RCC circuit to a non-isolated RCC circuit. This extraction of the isolation structure reduces component count and circuit complexity, lowering cost while improving conversion efficiency to above 80% by eliminating losses associated with isolation transformation.
2Ease of manufacture
If an RCC circuit is used, then cost is reduced, but power factor is not high
Solution Approach 1:
The patent introduces a valley-filling circuit that operates before the RCC circuit to pre-condition the input voltage waveform. This preliminary action fills the valleys of the rectified voltage waveform, transforming it into a more sinusoidal shape, which directly improves the power factor to above 0.9 while maintaining the cost advantages of the RCC architecture.
3Ease of manufacture
If an RCC circuit is used, then cost is reduced, but constant-current effect is bad
Solution Approach 1:
The patent implements a feedback control mechanism where the output current is sampled and fed back to the control circuit. This feedback loop continuously monitors and adjusts the driving current to maintain constant current output, significantly improving constant-current accuracy while preserving the cost-effectiveness of the RCC circuit through simple analog feedback components.
4Use of energy by moving object
If valley-filling circuit is added, then power factor is improved, but device complexity increases
Solution Approach 1:
The valley-filling circuit is designed as a localized preprocessing stage with specific components (capacitors, diodes, resistors) positioned at critical points in the input circuit. This local quality approach targets only the voltage waveform conditioning without complicating the entire system, achieving high power factor through focused, simple circuitry rather than system-wide 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
This configuration achieves a power factor greater than 0.9, improves conversion efficiency to over 90%, reduces heat generation, and enhances the service life of LED lamps while minimizing harmonic pollution and output ripples.
Implementation Method 1
a rectifier-filter circuit configured to convert an alternating voltage into a direct voltage
Implementation Method 2
a rectifier-filter circuit configured to convert an alternating voltage into a direct voltage
Implementation Method 3
a valley-filling circuit connected to the rectifier-filter circuit and configured to adjust a current waveform from the rectifier-filter circuit
Implementation Method 4
an electromagnetic interference (EMI) filtering unit, an input end of which is configured to receive the alternating voltage and an output end of which is connected to the rectifier-filter circuit, so as to suppress EMI
Implementation Method 5
a RCC circuit connected to the valley-filling circuit and configured to control a direct current (DC) output
Implementation Method 6
a DC output unit connected to the RCC circuit and configured to rectify and filter an output signal from the RCC circuit so as to drive an LED load
Implementation Method 7
a DC output unit connected to the RCC circuit and configured to rectify and filter an output signal from the RCC circuit
Data Source
AI summary
The present disclosure provides a light-emitting diode (LED) driver circuit and an electronic device. The LED driver circuit includes a rectifier-filter circuit configured to convert an alternating voltage into a direct voltage; a valley-filling circuit connected to the rectifier-filter circuit and configured to adjust a current waveform from the rectifier-filter circuit; a ringing choke converter (RCC) circuit connected to the valley-filling circuit and configured to control a direct current (DC) output; and a DC output unit connected to the RCC circuit and configured to rectify and filter an output signal from the RCC circuit so as to drive an LED load.