Grounded Voltage Protection Circuit for Linear LED Drivers
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Solution Overview
Problem
Linear LED lighting products face damage due to transient high voltages caused by parasitic capacitance in the heat dissipation insulation layer, failing to meet California Energy Commission (CEC) regulations for ring wave and lightning surge tests.
Innovation Solution
A grounded voltage protection circuit comprising an AC-DC power supply module, an LED module, a first voltage protection module, a drive IC, and a linear current adjustment module, which cooperates to discharge transient impulse voltages and prevent component damage by outputting preset voltage signals and control signals to adjust current output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat dissipation insulation layer is provided between the aluminum substrate and copper foil circuit layer, then heat dissipation performance is improved, but parasitic capacitance forms causing transient high voltage that damages components
Solution Approach 1:
A voltage protection module is introduced as an intermediary component between the power supply module and the LED module. This protection module includes a first voltage protection circuit that detects transient high voltage and a discharge circuit that actively discharges the voltage through a discharge switch and discharge resistor, preventing the harmful voltage from reaching and damaging the LED module while preserving the heat dissipation insulation layer's thermal management function.
2Reliability
If the heat dissipation insulation layer is connected to common ground, then electrical grounding is achieved, but the parasitic capacitance creates a transient path producing voltage shocks
Solution Approach 1:
The voltage protection module converts the harmful parasitic capacitance effect into a beneficial protective mechanism. The detection circuit monitors the transient voltage caused by parasitic capacitance, and when voltage shocks are detected, the discharge switch activates to create a controlled discharge path through the discharge resistor. This transforms the previously harmful transient voltage path into a safe, controlled discharge mechanism that protects the LED module while maintaining proper grounding.
3Device complexity
If transient impulse voltage is not discharged, then circuit simplicity is maintained, but driver IC and LED module are damaged due to overload output voltage
Solution Approach 1:
The voltage protection module implements preliminary protective action by continuously monitoring the voltage at its input terminal before the transient impulse voltage can reach and damage the LED module. The detection circuit is ready to detect voltage shocks in advance, and upon detection, the discharge switch immediately activates to discharge the voltage through the discharge resistor. This preliminary detection and response mechanism prevents component damage while adding minimal complexity to the overall circuit.
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 circuit effectively prevents damage from transient impulse voltages, enabling compliance with CEC regulations by safely managing voltage shocks and ensuring the longevity of the driver IC and LED module.
Implementation Method 1
the parasitic capacitance effect forms in such heat dissipation insulation layer. In addition, the heat dissipation insulation layer is connected to the common ground, and the parasitic capacitance therein will cause a transient path and produce a transient high voltage
Data Source
AI summary
A grounded voltage protection circuit for a linear drive circuit includes an AC-DC power supply module, a first voltage protection module, an LED module, a drive IC and a linear current adjustment module. Through the cooperation of the first voltage protection module, the drive IC and the linear current adjustment module, when a DC voltage signal output by the AC-DC power supply module exceeds a first preset voltage value, the first voltage protection module outputs the first preset voltage signal to prevent the drive IC and the LED module from being damaged due to the overvoltage output by the AC-DC module, and avoid the transient impulse voltage in the entire voltage protection circuit, thereby enabling the voltage protection circuit to pass the CEC certification.