LED Control Circuit with High Power Factor
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Solution Overview
Problem
Traditional LED constant current controlling methods result in low power factor and low efficiency due to limitations in voltage utilization and increased power consumption, with existing solutions either reducing LED strip utilization or increasing system costs.
Innovation Solution
An LED controlling circuit with high power factor, comprising multiple output current controlling modules and a reference voltage generating module, drives LED groups in a piecewise manner by connecting output current controlling modules to LED groups based on input voltage, without using sampling circuits or high-cost components, thereby improving power factor and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a linear constant current controlling circuit is used to control the LED strip, then the LED strip can work steadily with constant current, but the power factor is low when the rectified voltage is less than the conduction voltage of the LED strip
Solution Approach 1:
The LED strip is divided into multiple LED groups connected in series, with each group having its own output current controlling module. This segmentation allows each group to be independently controlled based on the input voltage level, enabling continuous current flow through at least one group while maintaining constant current operation for steady LED performance.
Solution Approach 2:
The control circuit dynamically connects different output current controlling modules to different LED groups based on the instantaneous input voltage level. As the input voltage varies during the AC cycle, the circuit automatically adjusts which LED groups are active, ensuring continuous operation and improving power factor without compromising LED reliability.
2Productivity
If a high voltage electrolytic capacitor is connected to filter the input voltage into DC, then the LED can be continuously on and current flows through the LED in the whole clock cycles, but the power factor is reduced and system cost increases
Solution Approach 1:
The invention extracts and utilizes the AC waveform information directly from the input voltage to control the LED groups through output current controlling modules. Instead of converting to DC and filtering with a large capacitor, the circuit uses the AC voltage levels to dynamically switch which LED groups are active, achieving continuous operation without the need for expensive and bulky electrolytic capacitors.
Solution Approach 2:
The invention replaces the traditional mechanical/electrical filtering system (electrolytic capacitor) with an electronic control system using output current controlling modules. This substitution eliminates the need for large capacitors while achieving the same goal of continuous LED operation, and additionally improves power factor by avoiding the energy storage and release characteristics of capacitive filtering.
3Productivity
If the amount of LEDs in the LED strip is decreased to reduce total forward conduction voltage, then current flows through the LED more continuously, but the utilization rate of input voltage is decreased and power consumption of driving circuit increases
Solution Approach 1:
The LED strip is segmented into multiple groups with different numbers of LEDs, allowing the circuit to activate different segments based on input voltage levels. This enables fine-grained control of current flow timing, maximizing the utilization of input voltage cycles without requiring reduced LED counts in individual groups.
Solution Approach 2:
The invention changes the control parameter from fixed LED configuration to dynamic selection of LED groups based on input voltage thresholds. By adjusting which LED groups are active according to real-time voltage levels, the system optimizes both continuous operation time and input voltage utilization, avoiding the need to reduce LED quantities.
Data Source
AI summary
The present invention is suitable for an LED controlling field, and provides an LED controlling circuit with high power factor and an LED lighting device. In the present invention, by using an LED current controlling circuit with high power factor comprising a plurality of output current controlling modules, a resistor Re and a reference voltage generating module, the LED groups is driven accordingly in a piecewise manner to be on and a current flows through the LED groups according to the input voltage of the LED strip, without sampling the input voltage of the LED strip by a sampling circuit and without increasing the number of high cost component, which increase the utilization of the LED, the power factor of the whole LED controlling circuit and the efficiency of the system, thereby solving the problem of low power factor and low efficiency system existing in the prior art.