LED Driver Feedback Circuit Stabilizes Voltage During Dimming
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing LED driving circuits face challenges in maintaining stable output voltage and current during dimming due to leakage currents, leading to reduced dimming accuracy and longer stabilization times.
Innovation Solution
A feedback control circuit that sustains a small amount of power conversion during the 'off' state of the dimming signal, keeping the output voltage close to the lighting threshold voltage, and includes a feedback unit and pulse width control unit with a dimming control unit to generate control signals for the converter circuit, ensuring steady illumination and minimizing power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the driving unit stops outputting the control signal during the OFF state of the dimming signal, then power loss is minimized, but the output voltage drops below the lighting threshold voltage due to leakage current
Solution Approach 1:
The patent applies periodic action by generating a periodic compensation signal during the OFF state of the dimming signal. This compensation signal is periodically added to the reference signal to counteract the voltage drop caused by leakage current, thereby maintaining the output voltage at or above the lighting threshold while minimizing power loss.
Solution Approach 2:
The patent implements feedback by detecting the output voltage level during the OFF state and using this information to generate an appropriate compensation signal. The compensation signal is adjusted based on the actual voltage drop, ensuring the output voltage remains stable at the lighting threshold without excessive power consumption.
2Loss of energy
If the converter circuit is completely stopped during the OFF state, then power loss is reduced, but the stabilization time increases when the next ON state begins
Solution Approach 1:
The patent applies preliminary action by maintaining the output voltage close to the lighting threshold during the OFF state through periodic compensation. This prepares the system in advance for the next ON state, reducing the stabilization time required when the dimming signal transitions from OFF to ON, while still minimizing power loss during the OFF period.
3Loss of energy
If the output voltage is allowed to drop during the OFF state, then power loss is minimized, but dimming accuracy is reduced
Solution Approach 1:
The patent uses feedback to maintain dimming accuracy during the OFF state by detecting the output voltage and applying periodic compensation signals. This ensures the voltage remains at the lighting threshold, preserving dimming accuracy while minimizing power loss compared to maintaining continuous full-power operation.
Data Source
AI summary
The present invention provides a feedback control circuit and an LED driving circuit for using the same, wherein the feedback control circuit receives a dimming signal. The dimming signal is changed between a first state and a second state. When being in the first state, the feedback control circuit controls a converter circuit to drive the LED module for lighting stably. When being in the second state, the feedback control circuit controls the converter circuit to maintain the power conversion of the converter circuit to have an output voltage outputted by the converter circuit maintained at a level close to a lighting threshold voltage of the LED module.