Adaptive Bleeder Control for LED Dimming Efficiency
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Solution Overview
Problem
In LED dimming systems using SCR dimming, the persistent closure of the bleeder current path affects system efficiency when the grid voltage is less than the LED conducted voltage, necessitating an adaptive control method to manage the bleeder current effectively.
Innovation Solution
An adaptive bleeder control circuit and method that detects the peak characterizing voltage of the grid, generates a switch control signal, and performs bleeder control to connect or disconnect the loop with the SCR in the light source device, using energy storage components to lock the peak voltage and manage the bleeder current accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bleeder current path is persistently closed to maintain SCR operation when grid voltage is less than LED conducted voltage, then the SCR can maintain normal operation, but system efficiency is affected
Solution Approach 1:
The bleeder current path is dynamically controlled rather than persistently closed. The control circuit detects grid voltage levels and automatically connects or disconnects the bleeder current path based on whether the grid voltage is sufficient to maintain SCR operation, thereby adapting the system state to changing conditions and eliminating unnecessary energy consumption
Solution Approach 2:
The control circuit implements feedback by detecting the grid voltage level and using this information to control the bleeder current path. The detection unit monitors grid voltage and provides feedback to the control unit, which then adjusts the bleeder current path accordingly, creating a closed-loop control system that optimizes both SCR reliability and system efficiency
2Loss of energy
If the bleeder current path is disconnected to improve system efficiency, then energy loss is reduced, but the SCR may be turned off when current is below minimum sustaining current
Solution Approach 1:
The system dynamically adjusts the bleeder current path connection state based on real-time grid voltage detection. When grid voltage is sufficient, the bleeder path is disconnected to save energy; when grid voltage drops below the threshold needed to maintain SCR conduction, the bleeder path is automatically connected to provide the necessary sustaining current, thus dynamically optimizing both efficiency and reliability
Solution Approach 2:
The detection unit continuously monitors grid voltage and provides feedback to the control unit. This feedback mechanism ensures that the bleeder current path is connected only when necessary (when grid voltage is insufficient), preventing SCR turn-off while minimizing energy consumption during normal operation
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
This solution enhances system efficiency by dynamically controlling the bleeder current, preventing persistent closure and ensuring optimal operation of the SCR, thereby maintaining efficient dimming functionality.
Implementation Method 1
storing energy by using an energy storage component while obtaining a grid voltage value; discharging by the energy storage component when the grid voltage is less than a preset input voltage value, to lock the peak characterizing voltage of the grid voltage
Data Source
AI summary
Embodiments of the present application disclose an adaptive bleeder control method and circuit, the method including: acquiring a peak characterizing voltage of a grid, wherein the peak characterizing voltage is a voltage value that characterizes a peak state among the grid characterizing voltages that are detected within a preset time and being scaled in proportion to the magnitude of the grid voltage; generating a switch control signal according to the peak characterizing voltage; performing switch control according to the switch control signal to generate a bleeder signal; and performing bleeder control on a light source device according to the bleeder signal to connect or disconnect a loop with a SCR in the light source device. In the present application, the dimming function of the light source device while preventing the bleeder current path from being constantly closed and reducing system efficiency may be implemented.