LED Lamp Shunt Switch for Ballast Ignitor Suppression
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Solution Overview
Problem
LED replacement lamps face challenges in compatibility with high-pressure Sodium and mercury vapor lamp ballasts, as the ignitor can activate due to high root mean square input voltage, requiring a solution to prevent ignitor activation and allow for dimmability while maintaining efficiency and reducing component count.
Innovation Solution
Incorporating a shunt switch in the rectifier circuit that provides a short circuit path to reduce the root mean square voltage and control the LED load current, using a sensing module to detect voltage dips and adjust the duty cycle of the shunt switch to manage ignitor activation and dimming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the LED replacement lamp is designed to be compatible with both high-pressure Sodium and mercury vapor lamp ballasts, then the adaptability is improved, but the device complexity increases due to the need to handle different ballast types and ignitor activation characteristics
Solution Approach 1:
The control circuit is designed to universally handle both high-pressure Sodium and mercury vapor lamp ballasts by detecting ballast type characteristics and automatically adapting its operation. The circuit can function as a simple rectifier for Sodium ballasts or as a regulated power supply with ignitor suppression for mercury vapor ballasts, making the LED replacement lamp compatible with multiple ballast types without requiring separate designs.
Solution Approach 2:
The control circuit dynamically changes its operating parameters based on the detected ballast type. For mercury vapor ballasts, it activates the shunt switch to suppress ignitor firing and regulates LED current; for Sodium ballasts, it operates as a simple full-wave rectifier without additional control, thereby adapting to different electrical characteristics of each ballast type.
2Object-affected harmful factors
If the root mean square input voltage is reduced to prevent ignitor activation, then the harmful factors are reduced, but the power delivered to the LED load decreases
Solution Approach 1:
The voltage control is segmented into two distinct phases: during ignitor suppression intervals, the shunt switch reduces voltage to prevent ignitor activation; during normal operation intervals, the full voltage is restored to deliver adequate power to the LED load. This temporal segmentation allows the system to address ignitor suppression without permanently compromising power delivery.
Solution Approach 2:
The shunt switch operates periodically to suppress ignitor activation only during specific portions of the AC cycle when the voltage would otherwise trigger the ignitor. By applying voltage reduction periodically rather than continuously, the system prevents ignitor activation while maintaining adequate average power delivery to the LED load throughout the operating cycle.
3Reliability
If a shunt switch is added to control voltage and prevent ignitor activation, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The shunt switch control functionality is merged with the existing full-wave rectifier circuit. The shunt switch is integrated into the rectifier topology, allowing it to suppress ignitor activation while simultaneously maintaining voltage regulation for the LED load. This merging approach adds the necessary ignitor suppression capability without requiring a completely separate voltage control circuit, thereby limiting the increase in device complexity.
4Device complexity
If the shunt switch is integrated in the rectifier circuit, then the device complexity is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The shunt switch is nested within the existing rectifier circuit structure, where it operates as an additional control element integrated into the familiar full-wave rectifier topology. This nesting approach allows the shunt switch to be incorporated into the rectifier's existing component layout and control logic, reducing overall device complexity while maintaining manageable manufacturing precision requirements through the use of standard rectifier design practices.
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
Effectively prevents ignitor activation by reducing the root mean square voltage, enables dimmability, and improves efficiency by integrating the shunt switch within the rectifier circuit, ensuring compatibility with various ballasts and maintaining a high power factor.
Implementation Method 1
A shunt switch integrated in the rectifier circuit or placed in front or after the rectifier circuit provides a short circuit path such that for a short period of time the voltage seen at the input of the LED replacement lamp is set to approximately zero Volts.
Implementation Method 2
The power converter transforms and rectifies the AC output from the ballast circuit to generate a DC output current.
Data Source
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AI summary
An LED replacement lamp compatible with a ballast of a high-pressure Sodium lamp and a ballast of a mercury vapor lamp, the LED replacement lamp comprising, input connections for receiving a voltage from a ballast, a rectifier circuit (D1, D2, D3, D4) for rectifying the received voltage into a DC voltage, a shunt switch (M1) arranged for regulating power to an LED load (LED), the shunt switch being coupled between output connections of the rectifier circuit output connections for connecting to the LED load a sensing circuit for sensing a parameter of the received voltage or the rectified voltage, wherein upon sensing of activation of an ignitor of the mercury vapor ballast, the shunt switch is operated such that a root mean square voltage at the input connection is reduced such that the ignitor turns off.