Dimmer Control Circuit for Flicker-Free LED Operation
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Solution Overview
Problem
LED dimmers, particularly those using silicon controlled rectifiers (SCR) or transistors, face issues with flickering due to the absence of a holding current or incorrect dimming circuit configurations, which affect the waveform output and brightness consistency of LED lamps.
Innovation Solution
A dimmer control circuit with a detection-control module and current holding module that determines whether an SCR-based leading-edge phase cut dimmer is connected, supplying a holding current when necessary, and disconnecting when not, to prevent flickering, and also handles trailing-edge phase cut dimmers and dimmer-less scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a leading-edge phase cut dimmer (SCR-based) is used to modulate LED lights, then the dimming function is achieved, but components like capacitors are needed to provide holding current, increasing device complexity
Solution Approach 1:
The patent introduces a detection module as an intermediary component that identifies the presence of SCR-based dimmers and triggers the capacitor to provide holding current only when needed. This mediator approach allows the system to maintain compatibility with SCR dimmers while avoiding unnecessary capacitor engagement with other dimmer types, thus reducing overall device complexity.
Solution Approach 2:
The patent implements dynamic control of the capacitor's holding current provision based on real-time detection of dimmer type. The system transitions from a static configuration where capacitors are always engaged to a dynamic system where capacitor engagement is conditionally activated only when SCR-based dimmers are detected, optimizing device complexity across different operating scenarios.
2Device complexity
If no dimmer or trailing-edge phase cut dimmer is used, then the device complexity is reduced, but the waveform output is influenced by capacitor charging/discharging, causing LED lamp flicker
Solution Approach 1:
The detection module serves as an intermediary that prevents the capacitor from interfering with trailing-edge dimmers or dimmer-less operations. By detecting the absence of SCR-based dimmers, the system activates the detection module to disconnect or deactivate the capacitor's holding current function, eliminating the source of waveform distortion and flicker while maintaining simple device architecture.
Solution Approach 2:
The system dynamically adjusts capacitor engagement based on detected operating conditions. When trailing-edge dimmers or dimmer-less modes are detected, the system transitions the capacitor from an engaged state to a disengaged state, preventing waveform distortion and flicker while maintaining device simplicity.
3Reliability
If a holding current is always supplied to support SCR-based dimmers, then the dimming operation is reliable, but the LED lamp flickers when trailing-edge dimmers or no dimmer is connected
Solution Approach 1:
The detection module acts as an intermediary that intelligently controls when the holding current should be supplied. It detects the presence of SCR-based dimmers and activates the holding current only in that specific scenario, while preventing holding current injection when trailing-edge dimmers or no dimmer is connected, thus eliminating flicker while maintaining reliable dimming operations.
Solution Approach 2:
The system implements feedback through the detection module that monitors the dimmer type and adjusts the holding current provision accordingly. This feedback mechanism ensures the holding current is supplied only when SCR-based dimmers are detected (preventing flicker with other types) while maintaining reliable operation with SCR dimmers, thus resolving the contradiction between reliability and flicker prevention.
Data Source
AI summary
The present disclosure provides a dimmer control circuit, a dimmer control method and a lighting device. The dimmer control circuit includes: a dimming output end configured to connect to a dimmer, a load terminal configured to connect to a load, a detection-control module, and a current holding module. An input end of the detection-control module is connected to an output end of the dimmer. An output end of the detection-control module is configured to: control the current holding module to connect to the load terminal when the dimming output end is connected to a SCR-based leading-edge phase cut dimmer, and control the current holding module to disconnect from the load terminal when the dimming output end is not connected to the SCR-based leading-edge phase cut dimmer. The current holding module is configured to supply a holding current to the SCR-based leading-edge phase cut dimmer connected to the dimming output end.