PCB-Based Sensor Package for Current Measurement
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Solution Overview
Problem
Current current sensors using lead frames, semiconductor substrates, or ceramic carriers are costly and suffer from limited sensitivity due to eddy currents and calibration issues, leading to decreased accuracy over the lifetime of the device.
Innovation Solution
A sensor package utilizing a printed circuit board as a mechanical carrier and insulator, with a laminar current conductor and a magnetic field sensor chip hermetically sealed within, eliminating the need for expensive mounting technologies and reducing eddy currents by using the PCB as a voltage insulation and mechanical support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lead frames, semiconductor substrates, or ceramic carriers are used for mounting the sensor chip, then the sensor package can be assembled, but the production costs increase and eddy currents are generated
Solution Approach 1:
The patent removes the lead frame, semiconductor substrate, or ceramic carrier from the sensor package assembly. The sensor chip is mounted directly on the printed circuit board without these intermediate mounting components, eliminating the source of eddy currents and reducing production costs while maintaining assembly capability
Solution Approach 2:
The printed circuit board serves as the direct mounting substrate for the sensor chip, replacing the traditional lead frame or ceramic carrier. The PCB provides both mechanical support and electrical insulation, acting as an intermediary that eliminates harmful eddy currents while enabling proper sensor chip assembly and positioning
2Measurement precision
If the sensor chip is placed close to the current conductor to measure the magnetic field, then the measurement sensitivity improves, but the electrical insulation requirements increase
Solution Approach 1:
The printed circuit board acts as an intermediary between the current conductor and the sensor chip. It provides adequate electrical insulation through its dielectric properties while allowing the sensor chip to be positioned close enough to the current conductor to detect the magnetic field with high sensitivity
Solution Approach 2:
The patent positions the sensor chip on the opposite side of the printed circuit board from the current conductor. This spatial arrangement in three dimensions allows the sensor to be close to the conductor for sensitivity while the PCB thickness provides the necessary electrical insulation distance
3Reliability
If conventional mounting technologies are used, then the sensor chip can be fixed, but warpage and drift occur over the device lifetime
Solution Approach 1:
The patent eliminates lead frames and specialized mounting substrates that can cause warpage. The sensor chip is mounted directly on the rigid printed circuit board, which provides stable mechanical support and maintains consistent positioning between the sensor and current conductor throughout the device lifetime
Solution Approach 2:
The printed circuit board provides its own mechanical rigidity and dimensional stability to prevent warpage, eliminating the need for additional warpage compensation mechanisms or specialized mounting structures
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 provides a cost-effective, sensitive, and stable current measurement by maintaining a consistent distance between the sensor chip and the current conductor, reducing warpage and drift, thus enhancing the reliability and accuracy of current intensity measurements.
Implementation Method 1
a sensor chip adapted to measure a current flowing through the laminar current conductor, wherein the sensor chip comprises a magnetic field sensor
Implementation Method 2
the sensor chip is electrically insulated from the current conductor by the printed circuit board
Data Source
AI summary
Some embodiments herein relate to a sensor package. The sensor package includes a printed circuit board with a laminar current conductor arranged on a first main surface of the printed circuit board. The sensor package also includes a sensor chip adapted to measure a current flowing through the laminar current conductor, wherein the sensor chip comprises a magnetic field sensor. The sensor chip is electrically insulated from the current conductor by the printed circuit board, and is arranged on a second main surface of the printed circuit board opposite to the first main surface. The sensor chip is hermetically sealed between the mold material and the printed circuit board, or is arranged in the printed circuit board and hermetically sealed by the printed circuit board.