LED Power Supply Voltage Regulation for Dimming Stability
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Solution Overview
Problem
Conventional LED lighting apparatuses experience unstable operating voltages in flyback control circuits when dimming is applied, leading to unstable operation as the brightness is reduced to a turn-off level, causing the flyback control circuit to malfunction due to excessively lowered voltage.
Innovation Solution
A power supply apparatus that includes a voltage converter with a transformer having an auxiliary coil with a variable winding ratio, allowing for voltage regulation of the detection voltage generated from the auxiliary coil, ensuring a stable operating voltage is supplied to the flyback control circuit through a voltage regulation circuit, even at dimming control levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the brightness of LED lighting is reduced to turn-off level through dimming control, then the driving current is decreased, but the operating voltage supplied to the flyback control circuit becomes unstable and drops to 14V or less
Solution Approach 1:
A voltage regulation circuit is introduced as an intermediary component between the auxiliary coil and the flyback control circuit. This circuit actively regulates the operating voltage to maintain it within the stable range of 14V to 20V, preventing the voltage instability that would otherwise occur during dimming operation. The voltage regulation circuit acts as a mediator that decouples the relationship between dimming control and voltage stability.
2Ease of operation
If the driving current is decreased to achieve dimming function, then the brightness is controlled, but the detection voltage from the auxiliary coil becomes excessively low causing flyback control circuit malfunction
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the winding ratio of the auxiliary coil based on the operating state. When the LED lighting is in dimming mode with low driving current, the auxiliary coil winding ratio is changed to increase the detection voltage level. This ensures the flyback control circuit receives sufficient voltage (14V to 20V) for stable operation while maintaining the desired dimming effect.
3Device complexity
If the auxiliary coil winding ratio is fixed, then the device complexity is reduced, but the operating voltage becomes unstable during dimming operation
Solution Approach 1:
The auxiliary coil is designed with a variable winding ratio that can be dynamically adjusted based on operating conditions. This dynamic configuration allows the system to optimize the detection voltage level for different dimming states. The winding ratio changes from a fixed value to a variable parameter controlled by the controller, enabling stable voltage supply during both full-power and dimming operation modes.
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 solution provides a stable operating voltage to the flyback control circuit, maintaining stable operation of the LED lighting even at turn-off levels, preventing voltage instability and ensuring consistent light emission.
Implementation Method 1
an auxiliary coil configured to include a second inductor and to supply a detection voltage corresponding to the current of the first inductor of the voltage converter
Implementation Method 2
a voltage regulation circuit configured to regulate the detection voltage and to supply the regulated voltage as an operating voltage for the controller
Data Source
AI summary
Disclosed are a power supply apparatus for an LED lighting and an LED lighting apparatus using the power supply apparatus. The LED lighting apparatus includes a power source unit configured to supply a rectified voltage, a voltage converter configured to include at least one first inductor and to convert the rectified voltage, an auxiliary coil configured to include a second inductor and to supply a detection voltage corresponding to the current of the first inductor of the voltage converter, a controller configured to control the current of the voltage converter using a driving pulse generated in response to a control signal and a sensing voltage, and a voltage regulation circuit configured to regulate the detection voltage and to supply the regulated voltage as an operating voltage for the controller.