LED Constant-Voltage Dimming Power Supply with PWM Control
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Solution Overview
Problem
Existing LED dimming systems that change current to adjust output power are limited in universality and consistency, especially when used with LED lamps that have built-in DC-DC drivers or linear current regulation, leading to flickering and inconsistent luminance across different loads.
Innovation Solution
An LED constant-voltage dimming power supply system that adjusts the duty ratio of output voltage using a phase detecting circuit module, damping discharge circuit, and switcher to control luminance, rather than relying on current limiting, ensuring compatibility and consistency across various LED lamps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the dimmer method of changing current is used to adjust output power, then the output power can be changed, but the luminance becomes inconsistent among different loads and LED lamps with built-in DC-DC drivers or linear current regulation will twinkle
Solution Approach 1:
The patent changes the control parameter from current to voltage. The LED constant-voltage dimming power supply outputs a constant voltage signal and uses PWM (pulse width modulation) to adjust the duty cycle of the voltage signal, thereby controlling the luminance of LED lamps without causing twinkling or inconsistency issues that occur with current-based dimming methods
Solution Approach 2:
The patent creates a universal dimming solution that works with various types of LED lamps including those with built-in DC-DC drivers and linear current regulation circuits. By using constant-voltage PWM dimming, the system achieves broad compatibility across different LED lamp types, eliminating the limitations of current-based dimming methods
2Power
If the dimmer method of changing current is used, then current can be regulated, but different loads with different current flowing through them result in different luminance
Solution Approach 1:
The patent switches from current regulation to voltage regulation with PWM control. The constant-voltage dimming power supply maintains a stable output voltage while varying the duty cycle, ensuring that different loads receive consistent voltage control signals regardless of their current requirements, thus achieving uniform luminance across diverse LED lamp types
3Power
If circuit resistance is present and current-based dimming is used, then power can be controlled, but luminance consistency deteriorates across multiple loads
Solution Approach 1:
The patent employs voltage-based PWM control instead of current control, changing the fundamental parameter used for power regulation. The constant-voltage output with adjustable duty cycle ensures that power control is achieved through time-domain modulation rather than amplitude control, eliminating the effects of circuit resistance variations and ensuring consistent luminance across multiple loads
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 system provides universal compatibility and consistent luminance adjustment for different LED lamps by controlling the duty ratio of the output voltage, eliminating flickering and ensuring consistent performance regardless of load variations.
Implementation Method 1
a phase detecting circuit module (23) electrically connected to an output end of the constant-voltage source (21)
Implementation Method 2
a damping discharge circuit module (22) electrically connected to an input end of the constant-voltage source (21)
Implementation Method 3
a switcher (25) electrically connected to the duty ratio controlling module (24); wherein the switcher (25) has a duty ratio which is adjustable according to a control signal from the duty ratio controlling module (24)
Data Source
AI summary
An LED constant-voltage dimming power supply being electrically connected to a dimmer and configured for changing duty ratio of output voltage thereof according to a controlling signal from the dimmer, includes a constant-voltage source, a damping discharge circuit module, a phase detecting circuit module, a duty ratio controlling module, and a switcher. The damping discharge circuit module is electrically connected to an input end of the constant-voltage source. The phase detecting circuit module is electrically connected to an output end of the constant-voltage source. The duty ratio controlling module is coupled to the phase detecting circuit. The switcher is electrically connected to the duty ratio controlling module. The LED constant-voltage dimming power supply adjusts the luminance of the LED lamp and has high universality. Moreover, each of lots of LED lamps has high consistency during adjusting its luminance.