Semiconductor Device Current Sense Ratio Stabilization
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Solution Overview
Problem
The current semiconductor devices with current sensing functions experience temperature-dependent variations in current sense ratios due to differences in resistance changing rates between the main element domain and the sense element domain, leading to inaccurate current detection.
Innovation Solution
The semiconductor device adjusts the impurity concentration and thickness of semiconductor layers in both the main element domain and the sense element domain to minimize the difference in temperature-dependent resistance changing rates, using the resistance ratios of each layer to account for current flow direction effects, thereby stabilizing the current sense ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of main elements in the main element domain is greatly different from the number of sense elements in the sense element domain, then the current sensing function can be achieved with appropriate current sense ratio, but the temperature-dependent resistance changing rates differ between the two domains causing the current sense ratio to change with temperature
Solution Approach 1:
The patent applies local quality by making the semiconductor layers in the main element domain and sense element domain have different characteristics. Specifically, the impurity concentration and/or thickness of corresponding semiconductor layers are made different between the two domains, so that the temperature-dependent resistance changing rates become substantially equal, thereby stabilizing the current sense ratio across temperature variations.
Solution Approach 2:
The patent changes physical parameters of the semiconductor layers, specifically the impurity concentration and thickness, to resolve the temperature dependence issue. By adjusting these parameters differently in the main element domain and sense element domain, the resistance changing rates with temperature are equalized, maintaining a stable current sense ratio.
2Ease of manufacture
If the thicknesses and impurity concentrations of semiconductor layers are set equally in both domains, then manufacturing is simplified, but the current sense ratio changes with temperature due to different resistance changing rates
Solution Approach 1:
Instead of using identical semiconductor layers in both domains, the patent introduces local quality differences by setting different impurity concentrations and/or thicknesses for corresponding semiconductor layers in the main element domain and sense element domain. This localized differentiation compensates for temperature effects while maintaining manufacturing feasibility.
Solution Approach 2:
The patent modifies the physical parameters (impurity concentration, thickness) of semiconductor layers to achieve temperature compensation. By carefully selecting different parameter values for the two domains, the resistance changing rates are equalized, ensuring accurate current sensing across temperature ranges.
3Reliability
If current flows obliquely with respect to the lamination direction of semiconductor layers in the sense element domain, then the effect of current flowing from outside the domain is accounted for, but the resistance values of semiconductor layers change making the current sense ratio temperature-dependent
Solution Approach 1:
The patent addresses the oblique current flow effect by introducing local quality differences in the semiconductor layers of the sense element domain. By adjusting impurity concentration and/or thickness, the resistance changing rate with temperature is matched to that of the main element domain, compensating for the oblique current flow effects.
Solution Approach 2:
The patent changes the physical parameters of semiconductor layers in the sense element domain to compensate for oblique current flow. By modifying impurity concentration and thickness, the resistance temperature dependence is equalized with the main element domain, maintaining accurate current sensing despite oblique current paths.
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 approach reduces temperature-dependent variations in the current sense ratio, enhancing the accuracy of current detection and eliminating the need for additional components to compensate for temperature-induced errors.
Implementation Method 1
the temperature-dependent resistance changing rate of each semiconductor layer and a resistance ratio of each semiconductor layer
Data Source
AI summary
Provided is a semiconductor device capable of reducing a temperature-dependent variation of a current sense ratio and accurately detecting current In the semiconductor device, at least one of an impurity concentration and a thickness of each semiconductor layer is adjusted such that a value calculated by a following equation is less than a predetermined value:[∑i=1n(RMi×kMi)-∑i=1n(RSi×kSi)]/∑i=1n(RMi×kMi)where a temperature-dependent resistance changing rate of an i-th semiconductor layer (i=1 to n) of the main element domain is RMi; a resistance ratio of the i-th semiconductor layer of the main element domain relative to the entire main element domain is kMi; a temperature-dependent resistance changing rate of the i-th semiconductor layer of the sense element domain is RSi; and a resistance ratio of the i-th semiconductor layer of the sense element domain to the entire sense element domain is kSi.