Metal Shunt Resistor With Nested Temperature Sensor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current shunt resistors in current-sensing systems suffer from inaccuracy due to their temperature dependency, which is compounded by inaccuracies in measuring the actual shunt temperature, leading to errors in current sensing.
Innovation Solution
A shunt resistor integrated with a semiconductor substrate and temperature-sensitive pn-junctions, where the temperature sensor is positioned below and within the periphery of the upper metal layer, allowing for improved thermal coupling and accurate temperature measurement, thereby reducing the temperature coefficient's impact on current sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is positioned outside the metal layer periphery, then the temperature measurement is simpler to implement, but the thermal coupling is insufficient leading to inaccurate temperature estimation
Solution Approach 1:
The temperature sensor is nested directly beneath the metal layer periphery, with its active area positioned within the boundary defined by the metal layer. This nested configuration ensures that the sensor is thermally coupled to the metal layer while maintaining a simple integration structure without requiring additional external connections or complex positioning mechanisms.
2Measurement precision
If the temperature sensor is positioned far from the shunt resistor, then parasitic resistances are reduced, but temperature gradients cause measurement errors
Solution Approach 1:
The temperature sensor is positioned locally beneath the metal layer periphery where it can directly measure the temperature at the shunt resistor location. This local positioning ensures that the sensor measures the actual temperature at the point of interest without being affected by temperature gradients in distant regions, while the metal layer provides thermal coupling to minimize local temperature variations.
3Reliability
If external precision shunts are used, then temperature coefficient is reduced, but board space and cost increase
Solution Approach 1:
The temperature sensor is merged with the shunt resistor structure by positioning it directly beneath the metal layer that forms the shunt current path. This integration allows the temperature sensor to be part of the shunt assembly itself, eliminating the need for separate external precision shunt components and reducing overall board space requirements while maintaining accurate temperature measurement for compensation.
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 configuration enhances the accuracy of shunt temperature estimation by three times, minimizing parasitic resistances and energy losses, and improves the overall precision of current sensing.
Implementation Method 1
a temperature sensor comprising at least a temperature-sensitive element comprising at least one pn-junction
Implementation Method 2
enhancing thermal coupling and reducing parasitic resistances to improve temperature measurement accuracy
Implementation Method 3
it heats by about 6° C. per 1 A current through the resistor
Data Source
AI summary
In one embodiment, a shunt resistor is provided, comprising two terminals, a semiconductor substrate embodying at least one temperature sensor comprising at least a temperature sensitive element comprising at least one pn-junction, and at least two metal layers above the semiconductor substrate, at least the upper of the metal layer comprising a path that electrically connects the two terminals, whereby the temperature sensor is below and within the periphery of the upper metal layer.