Silicon Controllable Dimming Circuit with Flick Elimination
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Solution Overview
Problem
Light Emitting Diodes (LEDs) experience flickering due to alternating current voltage waves, posing eye safety risks and stability issues.
Innovation Solution
A silicon controllable dimming full-range flickfree circuit is developed, incorporating a metal oxide semiconductor (MOS) connected with a dimming circuit, along with resistors, capacitors, and diodes to form a flick elimination circuit, which maintains constant current and voltage, eliminating flickering and stabilizing the LED operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If alternating current is used to power the LED, then the LED can operate with normal power supply, but the voltage wave causes flickering that endangers user eye safety
Solution Approach 1:
The patent introduces a periodic switching mechanism using a triac and control circuit that operates in synchronization with the AC cycle. By controlling the firing angle of the triac within each half-cycle, the circuit regulates LED current while maintaining continuous illumination, thereby eliminating flicker while enabling normal AC power operation.
Solution Approach 2:
The patent introduces intermediate components including a triac, diode bridge rectifier, and capacitor that act as mediators between the AC power supply and LED. These components convert AC to controlled DC, filtering out voltage fluctuations and eliminating flicker while maintaining compatibility with standard power supplies.
2Adaptability or versatility
If dimming control is added to the LED circuit, then brightness adjustment is achieved, but circuit complexity increases
Solution Approach 1:
The patent employs a dynamic control mechanism where the triac firing angle is continuously adjustable based on dimming input signals. This allows brightness adjustment across a wide range while using a relatively simple circuit topology that leverages the inherent dynamic characteristics of triac phase-angle control.
Solution Approach 2:
The patent designs a multi-functional control circuit that integrates dimming control, flicker elimination, and power factor correction capabilities into a single unified system. The control circuit accepts various dimming signal types (potentiometer, PWM, RC) and provides comprehensive LED driver functionality, reducing overall system complexity.
Data Source
AI summary
A silicon controllable dimming full-range flickfree circuit includes a dimming circuit and a flick elimination circuit which includes a metal oxide semiconductor (MOS) connected with an output terminal of the dimming circuit. The dimming circuit and the flick elimination circuit are combined, and the dimming circuit is provided with a silicon controllable dimming chip. Thus, when the MOS is worked at the constant current zone, the voltage of the source and the gate of the MOS is kept at a constant value, so that the current passing through the source and the drain of the MOS is kept at a constant value, to perform a flickfree feature of the full-power range of the high power factor, to stabilize the operation of the LED circuit, and to prevent the user's eyes from being hurt by the flick of the LED circuit.