Phase-Control Dimmer Circuit for Flicker-Free LED Compatibility
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Solution Overview
Problem
Existing dimmers are limited in their compatibility with various types of loads, particularly LED lighting systems, due to inefficiencies in power supply and control mechanisms, leading to issues like conduction losses and potential for abnormal operations such as blinking or flicker.
Innovation Solution
A dimmer design featuring a bidirectional switch, phase detector, power supply, and controller that modulates the bidirectional switch based on detected AC voltage phases to control power supply to the load, ensuring efficient power distribution and reducing errors in detection, thereby enhancing compatibility with a broader range of loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional dimmer with electrolytic capacitor-based power supply is used, then the dimmer can provide control power to the controller, but the dimmer exhibits conduction losses and reduced compatibility with various LED lighting systems
Solution Approach 1:
The patent changes the fundamental parameter of the power supply circuit by replacing the electrolytic capacitor-based rectifier circuit with a resonant circuit comprising a capacitor and inductor. This resonant circuit operates at a specific frequency to efficiently transfer power from the AC supply through the bidirectional switch to the controller, significantly reducing conduction losses and improving compatibility with various LED lighting systems while maintaining reliable control power supply.
2Ease of operation
If phase control is implemented using a bidirectional switch with electrolytic capacitor power supply, then the dimmer can control light output levels, but the system may exhibit abnormal operations such as blinking or flicker
Solution Approach 1:
The patent implements periodic action by using a resonant circuit that operates at a specific frequency synchronized with the AC power supply cycle. The resonant circuit is activated during specific time periods within each AC cycle to provide control power to the controller, ensuring stable and synchronized operation that prevents blinking or flicker while maintaining smooth dimming control.
Solution Approach 2:
The resonant circuit acts as an intermediary between the AC power supply and the controller, providing a stable and filtered power delivery mechanism. This intermediary circuit smooths out voltage fluctuations and provides consistent control power, preventing abnormal operations such as blinking or flicker that can occur with direct electrolytic capacitor-based power supply.
3Device complexity
If a simple power supply circuit with electrolytic capacitor is used, then the device complexity is reduced, but the measurement precision of AC voltage phase detection deteriorates
Solution Approach 1:
The resonant circuit serves as an intermediary that conditions the power signal before it reaches the controller, providing a clean and stable voltage reference for phase detection. This intermediary filtering action improves the signal-to-noise ratio, enabling more accurate phase detection by the controller without requiring complex detection circuitry.
Solution Approach 2:
The resonant circuit provides feedback information about the AC voltage phase and power delivery status to the controller, enabling precise synchronization of the bidirectional switch operation. This feedback mechanism ensures accurate phase detection and timing control, improving measurement precision while maintaining relatively simple circuit architecture.
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
The proposed dimmer design improves compatibility with more types of loads by reducing conduction losses and preventing abnormal operations, ensuring stable and efficient light output adjustment.
Implementation Method 1
The power supply is connected in parallel with the bidirectional switch, and configured to perform conversion operation to convert the AC power supply into prescribed control power
Implementation Method 2
The power supply has a capacitive device configured to store the control power
Implementation Method 3
The controller is configured to control the bidirectional switch based on a detection signal from the phase detector so that the bidirectional switch is in an off-state from a start point of a half cycle of the AC voltage to a first time point
Data Source
AI summary
A bidirectional switch is switched so as to conduct and interrupt a bidirectional current between a pair of input terminals. A power supply is electrically connected between the pair of input terminals and produces control power by electric power from an AC power supply. A controller receives the control power from the power supply to be activated. The controller causes the bidirectional switch to be in an off-state from a start point of a half cycle of AC voltage to a first time point when first time elapses. The controller causes the bidirectional switch to be in an on-state from the first time point to a second time point when second time according to the dimming level elapses. The controller causes the bidirectional switch to be in an off-state from the second time point to an end point of the half cycle.