PCB-Bezel Grounding Structure for Surge Voltage Protection
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Solution Overview
Problem
The existing electronic devices face challenges in protecting components from surge voltage, as ESD protection elements are expensive and do not reduce secondary noise, leading to increased production costs and risks of electric shock due to potential differences between metal frames and printed circuit boards.
Innovation Solution
The electronic device incorporates a structure with a metal side bezel and a printed circuit board, featuring a gap between conductive pads and a resistor or capacitor to manage voltage and prevent electric shock, reducing the need for expensive ESD protection elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ground area of the printed circuit board is spaced apart from the metal frame, then user safety from electric shock is improved, but potential difference increases and ESD current may flow during surge voltage events
Solution Approach 1:
The patent introduces an ESD protection element as an intermediary component between the metal frame and ground area. This element mediates the electrical connection, allowing normal operation while protecting against surge voltage by limiting potential difference and preventing harmful ESD current flow during voltage spikes.
Solution Approach 2:
The patent changes the electrical parameters of the connection between metal frame and ground by using ESD protection elements with specific breakdown voltage characteristics. This allows the system to maintain different electrical states under different conditions: low potential difference during normal operation, and controlled current path during surge events.
2Reliability
If an ESD protection element is disposed between the frame and ground area, then protection from surge voltage is improved, but production cost increases
Solution Approach 1:
The patent employs cost-effective ESD protection elements that can be integrated into the manufacturing process. These protection components are designed to be affordable while providing reliable surge voltage protection, making the overall device more cost-effective compared to alternative protection methods.
3Reliability
If an ESD protection element is used, then surge voltage protection is achieved, but secondary noise is not reduced
Solution Approach 1:
The patent applies different protection strategies at different locations in the circuit. ESD protection elements are placed between the metal frame and ground area to handle high-voltage surge events, while separate noise filtering components are implemented in signal paths to address secondary noise issues, providing localized solutions for different types of electrical disturbances.
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
This solution effectively protects components from surge voltage, reduces current flow in metal frames and printed circuit boards, preventing electric shock and secondary noise, while lowering production costs by eliminating the need for costly ESD protection elements.
Implementation Method 1
When the increased potential difference satisfies a specified condition (e.g., air gap breakdown condition), ESD current may flow from the frame to the printed circuit board.
Implementation Method 2
a resistor element disposed between the second conductive pad and the ground area of the printed circuit board
Implementation Method 3
a capacitor element disposed between a connector of the printed circuit board and the ground area
Data Source
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AI summary
An electronic device comprises: a first plate configured to face one surface of the electronic device; a second plate configured to face in a direction opposite to the first plate; a side bezel structure connected to the first plate and the second plate and configured to surround the side of the electronic device; and a printed circuit board mounted in the electronic device and configured to be connected to the side bezel structure, wherein the printed circuit board comprises: a ground area; a first conductive pad, disposed in one area of the printed circuit board, and configured to couple the side bezel structure and the printed circuit board; and a second conductive pad electrically connected to the ground area and disposed between the first conductive pad and the ground area, wherein the first conductive pad and the second conductive pad may be disposed at an interval through which a current, having a voltage equal to or greater than a threshold voltage between the first conductive pad and a second electrode, may flow.