Frequency Detection Circuit for LED Ballast Blinking
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Solution Overview
Problem
Existing LED lighting systems using electronic ballasts can experience intermittent high-frequency signal outputs, leading to blinking phenomena when the ballast is turned off, and the introduction of delay circuits to address this issue can cause overvoltage and failure risks, especially with non-preheating ballasts.
Innovation Solution
An electronic ballast-based device with two frequency detection circuits connected in parallel and an interface logic circuit to control the switching circuit, where one circuit is activated by low-frequency signals and the other by high-frequency signals, ensuring stable operation and preventing intermittent activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single frequency detection circuit is used in the electronic control circuit, then the circuit structure is simple, but the LED light source will blink intermittently when the ballast outputs intermittent high-frequency signals after being turned off
Solution Approach 1:
The frequency detection function is segmented into two independent circuits: a first frequency detection circuit for detecting high-frequency signals and a second frequency detection circuit for detecting low-frequency signals. Each circuit operates independently to detect different frequency ranges, allowing the system to distinguish between intentional high-frequency operation and residual signals after shutdown, thereby preventing intermittent blinking without requiring complex additional components.
2Reliability
If a delay circuit is added to prevent intermittent activation, then the blinking phenomenon is reduced, but the switch tube cannot be activated in time for non-preheating ballasts, causing overvoltage and increasing failure risk
Solution Approach 1:
The system dynamically selects between two frequency detection circuits based on the detected signal frequency. When a high-frequency signal is detected, the first circuit activates the switch tube immediately. When a low-frequency signal is detected (indicating ballast shutdown), the second circuit prevents activation. This dynamic switching mechanism eliminates the need for fixed delay circuits, ensuring immediate response for non-preheating ballasts while preventing intermittent activation after shutdown.
3Adaptability or versatility
If the electronic control circuit is compatible with both inductive ballast and electronic ballast, then the adaptability is improved, but the frequency detection requirement becomes more complex
Solution Approach 1:
The electronic control circuit achieves universal compatibility with both inductive ballasts and electronic ballasts through a dual frequency detection system. The first frequency detection circuit handles high-frequency signals from electronic ballasts, while the second frequency detection circuit handles low-frequency signals from inductive ballasts. This multi-functional detection approach allows a single control circuit design to work seamlessly with different ballast types without requiring complex additional control logic or components.
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 prevents flashing phenomena in LED lighting systems and reduces the risk of failure by providing a stable working signal and ensuring timely activation of the switching circuit, improving user experience and system reliability.
Implementation Method 1
A driving signal of the switch tube S is from a frequency detection circuit 124, and an input of the frequency detection circuit 124 is from a circuit between the filament analog circuit 121 and the rectifier bridge circuit 122
Implementation Method 2
the alternating-current voltage passes through the capacitor C10 to generate a certain current, whose magnitude is related to a capacitance value of the C10, an amplitude of the alternating-current voltage, and a frequency of the alternating-current voltage
Implementation Method 3
the alternating-current voltage passes through the capacitor C10 to generate a certain current, whose magnitude is related to a capacitance value of the C10, an amplitude of the alternating-current voltage, and a frequency of the alternating-current voltage. In the case that the alternating-current voltage is a power-frequency signal, a current flowing through the C10 is relatively small because the low-frequency condensance of the C10 is very large, thus the current passes through the D10 to generate a relatively low voltage on the R20 and the C20
Data Source
Figure 1~2
Figure 3a~3b
Figure 4~5
AI summary
The present invention provides an electronic ballast-based device for controlling an electronic control circuit and a lighting lamp. The device includes an electronic ballast and an electronic control circuit which are connected with each other, the electronic control circuit including a filament analog circuit, a rectifier bridge circuit, at least two frequency detection circuits connected in parallel, an interface logic circuit and a switching circuit; wherein the electronic ballast is connected with the switch circuit sequentially through the filament analog circuit and the rectifier bridge circuit; the at least two frequency detection circuits connected in parallel have one end connected between the filament analog circuit and the rectifier bridge circuit, or connected between the electronic ballast and the filament analog circuit, and the other end connected with the interface logic circuit; and the interface logic circuit is connected with the switching circuit. The lighting lamp with the above device can effectively avoid a flashing phenomenon when being switched off, which thus improves user experience with the lighting lamp.