Lamp Driving Circuit with Pre-Heating Detection for Double-Pin Safety
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Solution Overview
Problem
LED tube lamps with double-pin connectors pose a risk of electric shock during installation or replacement, as the connection pins at one end may be exposed and potentially dangerous when only one end is connected to a power supply.
Innovation Solution
A driving circuit with a pre-heating detection circuit and protection circuit is implemented, which detects the voltage between the connection pins and controls the switching circuit to prevent electric shock by turning the lighting unit on or off based on the input voltage compared to a reference voltage, ensuring safe operation during installation or replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lamp uses double-pin connectors for power supply, then the lamp can be powered by ballasts at both ends with AC current flow, but the connection pins at the unconnected end pose a risk of electric shock to installers during installation or replacement
Solution Approach 1:
The patent applies preliminary action by detecting the voltage state of connection pins before the lamp is fully installed or during replacement. The detection circuit checks whether connection pins are properly connected to the power supply beforehand, and only enables the lighting unit when both ends are correctly connected, preventing electric shock risk during installation or replacement operations
Solution Approach 2:
The patent introduces a detection circuit and control circuit as intermediary components between the power supply and the lighting unit. These intermediary circuits monitor the voltage state of connection pins and control the switching circuit accordingly, acting as a safety mediator that prevents direct exposure of installers to hazardous voltage at unconnected pins
2Reliability
If the pre-heating detection circuit detects voltage between connection pins to output reference voltage, then the protection circuit can compare and control the switching circuit, but the device complexity increases
Solution Approach 1:
The detection circuit serves multiple functions: it detects the voltage state of connection pins, outputs a reference voltage for comparison, and enables the control circuit to determine whether proper connection exists. This multi-functional design achieves safety protection while minimizing additional circuit complexity by making the detection circuit serve several purposes within the same structure
Data Source
AI summary
A driving circuit and a method for operating the driving circuit is provided for a lamp, the lamp includes a lighting unit, and a first and a second pair of connection pins for coupling the driving circuit to a power supply unit. The driving circuit includes a pre-heating detection circuit and a protection circuit. The pre-heating detection circuit is coupled to the first pair of connection pins and configured to detect a voltage between the first pair of connection pins and output a reference voltage. The protection circuit includes a switching circuit connected in series with the lighting unit, the protection circuit is configured to compare the reference voltage with an input voltage of the lamp and turn on the switching circuit to light the lighting unit when the input voltage of the lamp is greater than the reference voltage.