Constant Voltage Dimming Power Supply for LED Lighting
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Solution Overview
Problem
Existing dimming systems for LED lighting devices face instability and flickering due to phase-shifted sinusoidal waves with high-order harmonics, leading to uneven illumination and potential damage, and struggle with wide-range dimming due to voltage amplitude limitations and inaccurate high-voltage phase angle judgment.
Innovation Solution
A constant voltage dimming power supply with a rectifying circuit, constant voltage circuit, constant current load circuit, frequency conversion and protection sampling circuit, and switching circuit, along with an absorbing circuit and low voltage discharge circuit, to stabilize voltage, filter harmonics, and ensure accurate phase angle judgment, while providing a wide adjustable voltage range and real-time abnormality detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If phase-cut dimming is used to adjust lighting brightness, then energy saving and brightness control are achieved, but the output voltage contains high-order harmonics causing circuit current instability, flickering, and potential damage
Solution Approach 1:
The patent introduces a rectifying circuit as an intermediary component between the dimmer and the LED array. This rectifier converts the phase-shifted sinusoidal wave with high-order harmonics into a unidirectional current, eliminating the harmful AC components while preserving the dimming control signal. The rectifier acts as a buffer that isolates the LED driver from the distorted voltage waveform, thereby maintaining circuit stability and preventing flickering while retaining energy-saving benefits.
Solution Approach 2:
The patent transforms the electrical parameter of the input voltage from an AC phase-shifted waveform to a rectified DC waveform. By changing the voltage parameter through rectification, the system eliminates high-order harmonics and stabilizes the current flow to the LED array. This parameter transformation resolves the contradiction by converting the harmful AC signal into a stable DC signal that can be cleanly controlled for dimming without causing instability or flickering.
2Stability of the object's composition
If capacitor is used for rectification and filtering of mains voltage, then voltage stabilization is achieved, but residual voltage remains causing inaccurate high-voltage phase angle judgment and limiting dimming range
Solution Approach 1:
The patent extracts and removes the residual voltage from the circuit using a dedicated discharge circuit. After the rectifier and filter capacitor stabilize the voltage, the discharge circuit actively removes the remaining voltage that would otherwise interfere with phase angle detection. This extraction of harmful residual voltage allows for accurate high-voltage phase angle judgment while preserving the beneficial voltage stabilization provided by the capacitor.
Solution Approach 2:
The patent implements a feedback mechanism through the frequency conversion and protection sampling circuit that continuously monitors the circuit state. This feedback system detects the presence of residual voltage and controls the discharge circuit accordingly, dynamically adjusting to maintain accurate phase angle judgment. The feedback loop ensures that voltage stabilization and precise measurement are achieved simultaneously by actively managing residual voltage levels.
3Reliability
If constant current control is used to drive LED arrays, then consistent dimming effect and LED matching are achieved, but the system becomes sensitive to voltage fluctuations and requires complex protection circuits
Solution Approach 1:
The patent applies beforehand cushioning by placing protection circuits in advance before the constant current driver. The rectifying circuit and filter capacitor serve as protective buffers that pre-condition the voltage signal, removing harmful harmonics and stabilizing the voltage before it reaches the sensitive constant current control circuitry. This prior protection simplifies the overall system by preventing voltage fluctuations from reaching the LED driver, reducing the need for complex real-time protection mechanisms.
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 stable and consistent LED lighting output, prevents flickering and damage, and enables wide-range dimming by stabilizing voltage and current, improving matching with different dimmers and ensuring accurate high-voltage phase angle judgment.
Implementation Method 1
a rectifying circuit, configured to rectify and filter an output voltage regulated by dimmer
Implementation Method 2
a rectifying circuit, configured to rectify and filter an output voltage regulated by dimmer
Implementation Method 3
an absorbing circuit and low voltage discharge circuit, to stabilize voltage, filter harmonics
Implementation Method 4
low voltage discharge circuit, to stabilize voltage, filter harmonics, and ensure accurate phase angle judgment
Data Source
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AI summary
The invention relates to a constant voltage dimming power supply for lighting device, which is used for adjusting output voltage regulated by dimmer to realize constant voltage PWM output, including a rectifying circuit performing rectifier filtering to output voltage regulated by dimmer; a constant voltage circuit electrically connected to output end of the rectifying circuit; a constant current load circuit electrically connected to output end of the rectifying circuit; a frequency conversion and protection sampling circuit electrically connected to output end of the constant current load circuit and constant voltage; and a switching circuit for controlling lighting load illumination; the frequency conversion and protection sampling circuit converts an output signal of the constant current load circuit into a duty cycle signal suitable for controlling the switching circuit and detects the output abnormality of the constant voltage circuit in real time, and the switching circuit is controlled to be turned on and off accordingly. Compared with the prior art, the constant voltage dimming power supply provided by the invention can provide a stable current and voltage and can well protect the lighting load.