Ripple Suppression Circuit for LED Drivers
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Solution Overview
Problem
Switching power supplies driving LED loads often result in flicker due to power frequency ripples, and the use of large electrolytic capacitors to mitigate this can lead to decreased service life and lack of power factor correction.
Innovation Solution
A ripple suppression circuit that includes a switching converter and an LED lamp in series with the AC-DC switching power supply, where the difference voltage between the input and output signals of the switching converter follows the variation of the AC-DC switching power supply voltage, maintaining a DC current through the LED load and avoiding flicker, while also achieving power factor correction without increasing the average voltage or consuming extra power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a large electrolytic capacitor is used to store energy and provide DC voltage to decrease output current ripple, then the output current ripple is reduced, but power factor correction cannot be achieved and service life is decreased
Solution Approach 1:
The patent extracts the harmful ripple components from the output current by introducing a ripple suppression circuit that separates the DC component (useful) from the AC ripple component (harmful). The circuit extracts only the necessary DC energy for LED operation while rejecting the harmful ripple, thereby eliminating the need for large electrolytic capacitors and achieving both ripple reduction and improved service life.
Solution Approach 2:
The patent introduces an intermediary ripple suppression circuit between the switching power supply and the LED load. This intermediary circuit acts as a mediator that processes the power supply output, removing harmful ripple components while maintaining the necessary DC power delivery to the LEDs, thus resolving the contradiction between ripple reduction and service life extension.
2Stability of the object's composition
If a large electrolytic capacitor is used to store energy, then output current ripple is decreased, but power factor correction is not achieved
Solution Approach 1:
The patent designs a ripple suppression circuit that performs multiple functions simultaneously: it suppresses output current ripple, achieves power factor correction, and maintains DC power delivery to the LED load. This multi-functional circuit eliminates the need for separate components for each function, thereby resolving the contradiction between ripple reduction and power factor correction capability.
3Stability of the object's composition
If the difference voltage between input and output signals of the switching converter follows the variation of AC-DC switching power supply voltage, then a DC current is maintained through the LED load, but circuit complexity increases
Solution Approach 1:
The patent implements a control mechanism where the switching converter automatically adjusts its operation based on the input voltage variations. The controller monitors the AC-DC switching power supply voltage and self-adjusts the switching duty cycle to maintain constant DC current through the LEDs, eliminating the need for complex external regulation circuits and reducing overall system complexity while ensuring current stability.
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 effectively suppresses ripples in the load current, maintains a DC current through the LED load, and achieves power factor correction without increasing power consumption or requiring larger transistors for heat dissipation, thus extending the service life of the components.
Implementation Method 1
a ripple suppression circuit that includes a switching converter and an LED lamp in series with the AC-DC switching power supply
Data Source
AI summary
A method of suppressing ripple can include: (i) coupling a switching converter and a load in series between output terminals of a signal source; and (ii) controlling a difference voltage between an input voltage signal and an output voltage signal of the switching converter to vary with a voltage signal generated by the signal source to maintain a load current signal flowing through the load as a DC signal.