Embedded Precision Resistor for Compact PCB Current Measurement
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Solution Overview
Problem
Conventional printed circuit boards with precision resistors for current measurement are complex, expensive, and sensitive to vibrations, with limited installation space and reduced service life, particularly in downsized applications.
Innovation Solution
A printed circuit board design with a precision resistor embedded within the board, using a metal alloy with low temperature coefficient and low resistance variance, covered with insulating material, and integrated into the board structure via HDI circuits for precise current measurement, reducing installation space and production costs while enhancing durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the precision resistor is soldered onto an existing circuit as a surface-mountable component or connected via bonding wires, then the current measurement accuracy is achieved, but the production complexity and cost increase, and the service life is reduced due to vibration sensitivity
Solution Approach 1:
The precision resistor is integrated directly into the circuit board structure during the manufacturing process, merging the resistor component with the board itself. This eliminates the need for separate soldering or bonding wire connections, thereby reducing production complexity while maintaining measurement accuracy through the embedded configuration
Solution Approach 2:
The precision resistor is pre-integrated into the circuit board during manufacturing before final assembly. This preliminary integration action eliminates subsequent mounting steps and potential connection issues, reducing both production complexity and vibration sensitivity while preserving current measurement accuracy
2Measurement precision
If the precision resistor is soldered onto an existing circuit as a surface-mountable component or connected via bonding wires, then the current measurement accuracy is achieved, but the service life is reduced due to vibration sensitivity
Solution Approach 1:
The precision resistor is merged with the circuit board structure through embedding, creating a unified component that eliminates separate connections. This integration removes the resistor from vibration-prone mounting configurations, thereby enhancing reliability and service life while preserving measurement accuracy through the embedded configuration
Solution Approach 2:
The embedding process provides beforehand protection by securing the precision resistor within the circuit board structure before exposure to vibrational stresses. This prior cushioning through structural integration protects against vibration-induced failures, extending service life while maintaining measurement accuracy
3Measurement precision
If conventional surface-mountable components are used for precision resistors, then the current measurement function is achieved, but the installation space is increased
Solution Approach 1:
The precision resistor is merged with the circuit board structure, eliminating the need for separate component mounting areas. This integration allows the measurement function to be achieved within the existing board footprint, thereby reducing installation space while maintaining current measurement capability
Solution Approach 2:
The precision resistor is transitioned from a surface-mounted three-dimensional component to an embedded planar structure within the circuit board. This dimensional change from surface mounting to embedded configuration reduces the vertical profile and installation space requirements while preserving measurement precision through the integrated design
4Area of stationary object
If the precision resistor is embedded in the printed circuit board, then the installation space is reduced and production costs are decreased, but additional manufacturing steps are required
Solution Approach 1:
The precision resistor is integrated into the circuit board during the preliminary manufacturing stages before final assembly. This preliminary action incorporates the resistor formation and positioning into existing manufacturing workflows, reducing the need for additional separate manufacturing steps while achieving space reduction and cost savings
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 allows for cost-effective, compact, and long-lasting printed circuit boards with reduced sensitivity to vibrations, enabling precise current measurement and efficient heat and electricity management in circuit and power electronics.
Implementation Method 1
By measuring the voltage between the connection points and based on the known electrical resistance value, which generally changes only slightly in the relevant temperature range of 20 to 60°C due to the extremely low temperature coefficient of the materials used, the current flowing between the connection points can be determined with great accuracy
Implementation Method 2
The precision resistor (2) extends between the connection points (3) in the circuit board (1). The circuit board (1) has a layer of insulating compound (4) with a thickness of approx. 1000 μm, in which the precision resistor (2) is embedded
Data Source
Figure 1~2
AI summary
The invention relates to a printed circuit board (1) with at least two connection points (3) and at least one precision resistor (2) for measuring a current flowing between the connection points. The aim of the invention is to inexpensively produce a printed circuit board of the type mentioned in the introduction such that the printed circuit board has a reduced installation space while simultaneously having a preferably long service life. According to the invention, this is achieved in that the precision resistor extends between the connection points in the printed circuit board (11). The invention additionally relates to a corresponding method for producing said printed circuit board.