Automotive LED Input Protection Circuit for Transient Pulse Filtering
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Solution Overview
Problem
Existing automotive lighting systems using RGB LEDs require input protection against transient pulses, but current solutions like transient voltage suppressors are bulky and costly, posing challenges for compact design and cost-effectiveness.
Innovation Solution
An electronic assembly with a resistor and diode series connection, combined with capacitors, forms an input protection circuit that filters transient voltage and current without needing a bulky transient voltage suppressor, optimizing the design for RGB LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transient voltage suppressor is used for input protection, then the light source and driver are protected from transient pulses, but the device becomes bulky, costly and occupies excessive space
Solution Approach 1:
The patent extracts the essential protection function from the bulky transient voltage suppressor and implements it using discrete, compact components (resistors, capacitors, diodes) that provide the same protection effect while occupying minimal space on the circuit board
Solution Approach 2:
The patent replaces the expensive transient voltage suppressor with inexpensive, compact passive components (resistors, capacitors, diodes) that achieve the same protection function at lower cost and smaller size, making the solution economically viable for mass production
2Reliability
If a transient voltage suppressor is used for input protection, then the light source and driver are protected from transient pulses, but the device becomes costly
Solution Approach 1:
The patent substitutes expensive transient voltage suppressors with inexpensive passive components (resistors, capacitors, diodes) that provide equivalent protection functionality, significantly reducing the bill of materials cost and making the product more competitive in the automotive lighting market
3Device complexity
If standard capacitor values are used in the protection circuit, then the circuit is simple to design, but the protection against dangerous pulses is insufficient
Solution Approach 1:
The patent specifies optimized capacitor value ranges (first capacitor: 10-100 nF, second capacitor: 1-10 μF) that balance protection effectiveness against transient pulses with circuit simplicity, ensuring reliable protection while maintaining ease of implementation in standard automotive lighting designs
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 effectively filters transient pulses, protecting the driver and LED while reducing bulk and cost, making it suitable for interior lighting applications where compactness and efficiency are critical.
Implementation Method 1
a node between the protection input and the resistor group is connected to the ground through a first capacitor and a node between the resistor group and the protection output is connected to the ground through a second capacitor
Implementation Method 2
the diode's anode terminal is connected to the protection input directly or through the resistor... The diode's anode terminal being connected to the protection input allows current to flow freely towards the module driver while protecting the driver from current inversion
Implementation Method 3
the protection input and the protection output are connected by the interposition of a group of a resistor and a diode connected in series... the resistor has a resistor value comprised between 10 and 40 Ω
Data Source
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AI summary
The invention presents an electronic assembly for an automotive luminous device (10) comprising a light source (1), a driver (3) to control the light source (1) and an input protection circuit (2). The input protection circuit (2) is arranged between the power supply and the light source (1) and comprises a protection input (21) and a protection output (22). The protection input (21) and the protection output (22) are connected by the interposition of a resistor group comprising a resistor (23) and a diode (24) connected in series. A node between the protection input (21) and the resistor group is connected to the ground through a first capacitor (25) and a node between the resistor group and the protection output (22) is connected to the ground through a second capacitor (26).