LED Lamp Half-Wave Dimming Controller for Traffic Signals
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Solution Overview
Problem
Existing LED replacement signal lamps for traffic control systems lack dimming capabilities, as the switching power supplies used in these lamps produce the same light level from both full-wave and half-wave rectified power signals, nullifying the dimming capabilities of traditional street traffic controllers.
Innovation Solution
An LED lamp assembly with a power supply and dimming controller that adjusts the DC lamp current based on the input power signal, determining whether full or dimmed brightness is required by detecting the zero-level duration of the input power signal and maintaining different current levels for full and dimmed brightness, allowing the lamp to be physically and electrically compatible with incandescent signal lamps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If LED replacement signal lamps use standard switching power supplies, then power consumption is reduced and reliability is improved, but dimming capabilities are lost because the power supplies produce the same light level from both full-wave and half-wave rectified power signals
Solution Approach 1:
The patent applies dynamics by making the LED lamp's brightness level adjustable based on the input power signal type. The system dynamically switches between full brightness mode (when full-wave rectified power is detected) and dimmed brightness mode (when half-wave rectified power is detected), allowing the lamp to adapt its light output characteristics to match the controller's dimming commands while maintaining efficient LED power conversion.
Solution Approach 2:
The patent changes the brightness parameter of the LED lamp based on the detected power signal type. By monitoring whether the input power is full-wave or half-wave rectified, the system adjusts the LED current accordingly - maintaining full current for full-wave input and reducing current for half-wave input - thereby restoring dimming functionality without changing the physical structure or LED elements themselves.
2Ease of operation
If LED replacement lamps are designed for compatibility with incandescent standards, then ease of installation and system integration are improved, but the electrical characteristics must be modified to enable dimming response
Solution Approach 1:
The patent achieves universality by designing the LED replacement lamp to interface with existing incandescent traffic signal systems while adding intelligence to detect and respond to dimming commands. The lamp maintains physical and electrical compatibility with standard sockets and wiring, yet incorporates a microcontroller that can interpret half-wave rectified power signals as dimming commands, allowing one lamp design to serve both legacy and modern dimming applications.
Solution Approach 2:
The patent introduces a microcontroller as an intermediary between the power supply circuitry and the LED elements. This intermediary component monitors the input power signal characteristics, detects whether half-wave or full-wave rectification is present, and accordingly adjusts the LED drive current. This mediator enables the lamp to translate legacy electrical signals into appropriate brightness levels without requiring changes to the external controller or wiring infrastructure.
3Illumination intensity
If full-wave rectified power is applied to LED replacement lamps, then full brightness is achieved, but energy efficiency is reduced compared to half-wave operation
Solution Approach 1:
The patent implements feedback by having the microcontroller continuously monitor the input power signal characteristics and adjust the LED brightness accordingly. When half-wave rectified power is detected (indicating a dimming command from the controller), the system feedback-reduces the LED current to maintain appropriate brightness while saving energy. This closed-loop approach ensures the lamp responds efficiently to controller commands without wasting power during nighttime dimming operations.
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
Enables dimmable LED signal lamps that produce full brightness when full-wave power is applied and dimmed brightness when half-wave rectified power is applied, effectively restoring dimming capabilities in traffic control systems, enhancing energy efficiency and safety by reducing glare and energy consumption.
Implementation Method 1
the switching power supplies used in the LED replacement lamps need only a small amount of input power and consequently produce the same light level from both full-wave and half-wave rectified supply power
Implementation Method 2
small switching power supplies are typically included in the LED replacement signal lamp assemblies to convert the AC mains voltage supplied by the existing traffic control system into the low level DC voltage required by the LED light elements
Implementation Method 3
Replacing incandescent signal lamps with Light Emitting Diode (LED) light sources, also known as LED Lights or LED lamps
Implementation Method 4
The LED light elements used in these replacement signal lamps require low level DC power
Data Source
AI summary
An LED lamp assembly includes a power supply configured to receive an input power signal and provide a DC lamp current, a dimming controller coupled to the power supply and configured to adjust the DC lamp current, and an LED lamp coupled to the DC lamp current. The dimming controller is configured to determine if full brightness or dimmed brightness is required based at least in part on the input power signal. The DC lamp current is maintained at a first level when full brightness is required and at a second level when dimmed brightness is required.