Multi-Bridge Current Shunt for Stable High-Current Measurement
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Solution Overview
Problem
Existing current measurement techniques in power semiconductor devices are inaccurate in large current conditions, such as those exceeding 10A, due to high operational temperatures that lead to unreliable voltage drops and mechanical failure of encapsulating materials.
Innovation Solution
A metal clip with a multi-bridge configuration is used in a current shunt measurement arrangement, comprising landing pads made of thermally conductive metals and bridge spans made of resistive alloys with low temperature coefficients, allowing for accurate current measurement by maintaining stable electrical resistance and dissipating heat effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a shunt resistor is used for current measurement in high current conditions, then current measurement is obtained, but temperature rise leads to voltage drop inaccuracies and mechanical failure
Solution Approach 1:
The shunt resistor is divided into multiple resistive sections (first, second, third sections) connected in series, with intermediate connection points providing thermal relief. This segmentation reduces the temperature rise in each individual section while maintaining the total resistance needed for accurate current measurement.
Solution Approach 2:
Intermediate connection points are introduced between the resistive sections, which serve as thermal intermediaries to dissipate heat and reduce the temperature gradient across the shunt resistor, thereby improving measurement accuracy in high current conditions.
2Measurement precision
If high resistance value is used in shunt resistor for accurate current measurement, then measurement precision improves, but temperature rise increases leading to mechanical failure
Solution Approach 1:
The high resistance value is achieved through multiple series-connected resistive sections rather than a single section. This segmentation allows the total resistance to be distributed across multiple thermal zones, preventing localized overheating and mechanical failure while maintaining the voltage drop accuracy needed for precise current measurement.
3Device complexity
If conventional shunt design is used, then simple structure is maintained, but temperature-related measurement errors occur in high power applications
Solution Approach 1:
The shunt resistor is segmented into multiple resistive sections with intermediate connection points, creating a more complex structure that actively manages thermal distribution. This segmentation improves measurement reliability in high power applications by reducing temperature-related errors, while still maintaining a relatively simple overall design.
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 precise current measurement with reduced temperature-related inaccuracies and mechanical stability, enabling accurate current measurement in high-power applications without reaching damaging temperatures.
Implementation Method 1
the first and second bridge spans comprise sections of a first conductive material that the shunt current must pass through
Implementation Method 2
the first, second third landing pads are respectively thermally conductively attached to first, second and third contact pads
Implementation Method 3
a temperature coefficient of the first conductive material is lower than that of the first, second and third landing pads
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
An electronic device includes a structured metallization layer including a plurality of contact pads that are electrically isolated from one another, and a metal clip connected in a current shunt measurement arrangement with a semiconductor device, wherein the metal clip includes first, second and third landing pads, a first bridge span connected between the first and second landing pads, and second bridge span connected between the second and third landing pads, wherein the first, second third landing pads are respectively thermally conductively attached to first, second and third contact pads from the structured metallization layer, and wherein the second mounting pad is electrically floating.