LED Driver Circuit Balancing Efficiency and Power Factor
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Solution Overview
Problem
Existing LED driving circuits face a trade-off between efficiency and power factor, where high efficiency leads to low power factor and vice versa, making it challenging to simultaneously optimize both.
Innovation Solution
An LED driving circuit comprising a voltage input module, an LED load, a constant current control module, and a current turn-off slope control module, where the current turn-off slope control module adjusts the turn-off slope of the current flowing through the LED load when the input voltage exceeds a set value, balancing efficiency and power factor by outputting a turn-off signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the input voltage is increased to improve power factor, then the power factor is improved, but the efficiency decreases due to increased system loss and heat generation
Solution Approach 1:
The patent implements dynamic current control by introducing a current turn-off slope control module that adjusts the current flowing through the LED load based on the input voltage level. When the input voltage exceeds a predetermined threshold, the module progressively reduces the current in a controlled manner, enabling the system to adapt to varying voltage conditions and optimize the balance between power factor and efficiency.
Solution Approach 2:
The patent changes the operating parameters of the LED driving circuit by dynamically adjusting the current magnitude and turn-off slope based on the input voltage level. This parameter adaptation allows the system to operate efficiently across different voltage conditions, resolving the contradiction between maintaining high power factor and preserving efficiency.
2Use of energy by moving object
If the current is reduced when input voltage is excessively high to improve efficiency, then the efficiency is improved, but the power factor will decline
Solution Approach 1:
The current turn-off slope control module dynamically adjusts the current reduction rate based on the input voltage level. Instead of abrupt current cutoff, the module implements a controlled slope that progressively reduces current, thereby maintaining smoother power factor characteristics while still improving efficiency under high voltage conditions.
Solution Approach 2:
The patent employs periodic monitoring of the input voltage level and implements periodic current adjustment cycles. The control module continuously evaluates whether the input voltage exceeds the threshold and applies current reduction in a rhythmic, controlled manner, which helps maintain stable power factor while achieving efficiency improvements.
3Loss of energy
If a linear LED driver is used with high input voltage to achieve high power factor, then the power factor is high, but the efficiency is relatively low
Solution Approach 1:
The patent transforms the static linear LED driver into a dynamic system by adding the current turn-off slope control module. This module continuously monitors the input voltage and dynamically adjusts the current characteristics, enabling the driver to maintain high power factor at normal voltages while automatically optimizing efficiency when high input voltage occurs.
Solution Approach 2:
The patent changes the operational parameters of the linear LED driver by introducing voltage-threshold-based current control. When the input voltage exceeds the predetermined threshold, the system modifies the current magnitude and turn-off characteristics, thereby adjusting the operating point to achieve better efficiency without compromising power factor at standard voltage levels.
Data Source
AI summary
A LED driving circuit and method for balancing efficiency and a power factor. The circuit comprises a voltage input module, an LED load, a constant current control module and a current turn-off slope control module for adjusting the turn-off slope of the current flowing through the LED load, such that a compromise between efficiency and power factor is achieved. When an input voltage is higher than a setting voltage, the current flowing through the LED load is turned off, such that the power consumption is reduced; in addition, the efficiency and power factor are balanced by adjusting the turn-off slope of the current. According to the present invention, a compensation capacitor is used to control the average current in an alternating current period and to limit peak current, thereby implementing constant power output within a wide range of input voltage.