Controllable-Load Circuit for LED Dimmer Holding Current
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Solution Overview
Problem
Existing load control systems for LED light sources often waste power by conducting current through dimmer switches unnecessarily, as they do not have the ability to adjust current delivery in response to changing power requirements, leading to inefficiencies when controlling high-efficiency loads like LEDs.
Innovation Solution
A controllable-load circuit that adjusts the magnitude of the current conducted through a dimmer switch based on the conduction time of a phase-control voltage, ensuring the current exceeds the rated holding current only when necessary, thereby optimizing power delivery to LED light sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the load control circuit conducts current through the dimmer switch continuously, then the dimmer switch receives sufficient holding current to remain conductive, but power is wasted unnecessarily when the LED load requires minimal power
Solution Approach 1:
The load control circuit dynamically adjusts the magnitude of current conducted through the dimmer switch based on real-time monitoring of the phase-control voltage conduction time. When the LED load requires minimal power (short conduction time), the circuit reduces current magnitude to minimal levels sufficient for holding current, thereby reducing power wastage while maintaining dimmer switch conduction reliability.
Solution Approach 2:
The system changes the parameter of current magnitude from a fixed continuous value to a variable value that adapts to the actual power requirements of the LED load. By monitoring conduction time and adjusting current magnitude accordingly, the system optimizes the balance between power efficiency and dimmer switch operation.
2Loss of energy
If the load control circuit reduces current magnitude to minimal levels, then power efficiency is improved, but the dimmer switch may fail to maintain conduction
Solution Approach 1:
The load control circuit continuously monitors the conduction time of the phase-control voltage received from the dimmer switch and uses this feedback to adjust the current magnitude. This closed-loop control ensures that the current is reduced to minimal levels only when the conduction time indicates the LED load requires minimal power, while maintaining sufficient current to keep the dimmer switch conductive.
Solution Approach 2:
The system uses the dimmer switch's own operational characteristics (conduction time of phase-control voltage) to automatically regulate the current magnitude, eliminating the need for external control mechanisms. The load control circuit self-adjusts based on the dimmer switch's performance, optimizing power efficiency while ensuring reliable conduction.
3Productivity
If the load control circuit monitors and adjusts current based on conduction time, then power delivery is optimized, but the device complexity increases
Solution Approach 1:
The load control circuit performs multiple functions using a unified approach: it monitors the phase-control voltage conduction time, determines LED power requirements, adjusts current magnitude, and ensures dimmer switch conduction all through a single integrated control mechanism. This multi-functionality reduces the need for separate control circuits and simplifies the overall system architecture.
Data Source
AI summary
A load control device for controlling the amount of power delivered from an AC power source to an electrical load is operable to conduct enough current through a thyristor of a connected dimmer switch to exceed rated latching and holding currents of the thyristor. The load control device comprises a controllable-load circuit operable to conduct a controllable-load current through the thyristor of the dimmer switch. The load control device disables the controllable-load circuit when the phase-control voltage received from the dimmer switch is a reverse phase-control waveform. When the phase-control voltage received from the dimmer switch is a forward phase-control waveform, the load control device is operable to decrease the magnitude of the controllable-load current so as to conduct only enough current as is required in order to exceed rated latching and holding currents of the thyristor.