Synchronous LED Start-Up Circuit for Deep Dimming Channels
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Solution Overview
Problem
Existing LED power supplies face challenges in synchronizing the startup of multiple LED lamps due to varying dimming depths, leading to response delays and unpleasant user experiences.
Innovation Solution
A synchronous start-up circuit and constant current deep dimmable power supply that uses enabling and starting switch circuits to synchronize the startup of LED luminaires by controlling the output voltage and timing of constant current sources, ensuring all LED luminaires start simultaneously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the capacitance of electrolytic capacitors is increased to reduce current ripple and improve output stability, then the output stability is improved, but the charging time becomes longer and startup synchronization deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-charging the electrolytic capacitors through a dedicated charging circuit before the LED luminaires start operating. The charging circuit activates first to charge all channel capacitors to the required voltage level, ensuring they are ready for simultaneous startup. This preliminary charging action separates the charging process from the operational startup, allowing capacitors with larger capacitance values to be charged without extending the operational startup time, thus resolving the contradiction between output stability and charging time.
2Adaptability or versatility
If different dimming depths are set for multi-channel LED power supplies, then individual channel control flexibility is improved, but startup synchronization deteriorates due to varying charging times
Solution Approach 1:
The patent applies segmentation by dividing the power supply system into independent charging circuits for each channel, with each channel having its own controllable charging path. The control circuit can independently adjust the charging current and timing for each channel based on the required dimming depth, while still coordinating to achieve simultaneous startup. This segmented architecture allows flexible dimming control for each channel without affecting the synchronization capability of other channels.
Solution Approach 2:
The patent implements feedback through voltage detection circuits that monitor the charging status of each channel's electrolytic capacitor. The control circuit receives feedback signals from these detection circuits and adjusts the charging current accordingly. When a channel reaches the required voltage level, the feedback signal triggers the startup switch to activate that channel. This feedback mechanism ensures that channels with different dimming depth requirements can be charged at different rates while still achieving synchronized startup when all channels reach their respective threshold voltages simultaneously.
3Reliability
If a preset time delay is introduced before the synchronized start signal to ensure capacitors are charged, then startup voltage readiness is improved, but response time increases
Solution Approach 1:
The patent replaces fixed time delay with feedback-based voltage detection. The detection circuit continuously monitors the voltage across each channel's electrolytic capacitor and provides real-time feedback to the control circuit. When the voltage reaches the predetermined threshold indicating sufficient charge, the feedback signal immediately triggers the startup switch. This eliminates the need for conservative preset delays, allowing the system to respond as soon as capacitors are actually ready, thus reducing response time while ensuring reliable voltage readiness.
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
Ensures simultaneous and timely startup of LED luminaires, improving user experience by eliminating response delays and synchronizing the power supply across multiple channels.
Implementation Method 1
it is necessary to increase the capacitance of electrolytic capacitors in the output circuit
Implementation Method 2
the constant current source discharges to supply power to the LED luminaire
Data Source
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Figure 3
Figure 4~5
AI summary
The present invention discloses a synchronous start-up circuit and a constant current deep dimmable power supply; when the output voltage of the constant current source does not reach the start voltage of the LED luminaire, the enabling switch circuit and the starting switch circuit are both disconnected; when the output voltage of the constant current source reaches the start voltage of the LED luminaire, the enabling switch circuit turns on and outputs a power-off signal, which is used for controlling the constant current source to no longer output the current to wait for the output voltage of other constant current sources to reach the start voltage of the corresponding LED luminaire. When the output voltage of the constant current source reaches the starting voltage of the corresponding LED luminaire, taking the moment when the constant current source starts to output voltage as the starting point; after a preset time, each starting switch circuit receives a synchronized starting signal, each starting switch circuit is turned on, and each constant current source discharges to supply power for the LED luminaire, thus realizing the simultaneous starting of multiple LED luminaires and the timely starting of each single LED luminaire.