Wide Input Voltage Phase-Cut Dimming Circuit for LED Drivers
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Solution Overview
Problem
Current phase-cut dimming power supplies have a narrow input voltage range, making them unsuitable for most global electric networks, which require a range of 90-305V and are not compatible with both forward and reverse phase-cut dimming modes.
Innovation Solution
A wide input voltage phase-cut dimming circuit that includes a phase-cut dimmer, a switching power supply, a field effect transistor, and a PWM signal conversion circuit, allowing for a dimming range of 0-100% and compatibility with input voltages from 90-305V by generating a PWM signal with a frequency greater than 200 Hz, independent of the alternating current voltage magnitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a phase-cut dimming power supply is designed for a specific voltage range (e.g., 170-265V or 90-130V), then it can work reliably within that range, but it cannot be universally compatible with different global electric networks requiring 90-305V input range
Solution Approach 1:
The circuit employs a universal design that accepts both forward phase-cut (TRIG) and reverse phase-cut (Reverse TRIG) dimming signals through a single input interface. The diode bridge configuration allows the circuit to process either polarity of phase-cut signal, making it universally compatible with different regional dimming standards while maintaining stable operation across the extended 90-305V input voltage range.
Solution Approach 2:
The circuit dynamically adapts to different input voltage levels (90-305V) by using a voltage-dependent triggering mechanism. The RC timing circuit and diode bridge configuration automatically adjust the firing angle based on the input voltage magnitude, allowing reliable operation across the wide voltage range without requiring separate circuits for different voltage standards.
2Device complexity
If a low frequency PWM signal is used for dimming control, then the circuit is simple to implement, but human eyes can perceive obvious flickers
Solution Approach 1:
The circuit generates a high-frequency PWM signal (≥200Hz) that switches the LED driver at a rate too fast for human visual perception. This periodic switching action eliminates visible flicker while maintaining simple circuit implementation through the use of standard PWM generation techniques with the field effect transistor and diode bridge configuration.
3Ease of operation
If the PWM signal duty cycle depends on alternating current voltage magnitude, then the circuit responds to voltage variations, but the dimming range cannot be controlled independently of voltage fluctuations
Solution Approach 1:
The circuit introduces an intermediary RC timing circuit and diode bridge that decouples the PWM duty cycle from direct AC voltage magnitude dependence. The RC circuit generates a reference timing signal that is independent of voltage fluctuations, while the diode bridge rectifies and conditions the phase-cut signal. This intermediary mechanism allows the dimming duty cycle to be controlled solely by the phase-cut signal timing, enabling independent dimming control regardless of AC voltage variations.
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 phase-cut dimming power supply that is compatible with a wide range of input voltages, eliminating flicker perception and enabling seamless dimming control across various global electrical networks.
Implementation Method 1
a photoelectric coupler; an output of the photoelectric coupler is connected to an input of the PWM signal conversion circuit
Data Source
AI summary
The present invention discloses a wide input voltage phase-cut dimming circuit, which is connected and works in the overall dimming circuit. The overall dimming circuit includes a phase-cut dimmer, a dimming circuit, and an LED lamp. The dimming circuit includes a wide input voltage phase-cut dimming circuit, a switching power supply, a field effect transistor. The wide input voltage phase-cut dimming circuit includes a photoelectric coupler, and a PWM signal conversion circuit. The source and drain terminals of the field effect transistor are connected in series between the negative terminal of the output of the switching power supply and the negative terminal of the LED lamp. The output of the wide input voltage phase cut dimming circuit is connected to the gate of the field effect transistor. The output of the field effect transistor is controlled by the PWM signal conversion circuit.