Capacitive Semiconductor Temperature Sensor for Low Power
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Solution Overview
Problem
Conventional temperature sensors face challenges in achieving low power dissipation and robustness against magnetic fields, which can affect measurement accuracy and reliability, especially in applications where heating and magnetic interference are concerns.
Innovation Solution
A temperature sensor design featuring a semiconductor layer with distinct layer portions, where a dielectric first layer portion and a doped second layer portion with temperature-dependent resistance are used, allowing for precise temperature measurement with minimal power dissipation and magnetic field resistance, integrated with a measurement circuit and method for determining temperature based on capacitance and resistance variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional temperature sensors (pn-diodes or measurement resistors) are used, then temperature measurement is achieved, but power dissipation increases causing heating that influences measurement accuracy
Solution Approach 1:
The patent replaces conventional current-based temperature sensing (pn-diodes or measurement resistors requiring constant current) with a capacitive sensing mechanism. The temperature sensor comprises a capacitor where at least one electrode is formed by a semiconductor layer with temperature-dependent capacitance characteristics, eliminating the need for continuous current flow and thus reducing power dissipation at the sensor location.
Solution Approach 2:
The patent utilizes the temperature-dependent capacitance parameter of the semiconductor layer instead of temperature-dependent resistance. By measuring capacitance changes rather than resistance changes, the sensor achieves temperature measurement with minimal power consumption, as capacitive measurement can be performed with very low DC power dissipation.
2Loss of energy
If conventional capacitive temperature sensors based on dielectric materials are used, then power dissipation is minimized, but robustness against magnetic fields deteriorates
Solution Approach 1:
The patent changes the material parameter from conventional dielectric materials to semiconductor materials with appropriate carrier concentrations. The semiconductor layer exhibits both low power dissipation (capacitive behavior) and magnetic field robustness (through its specific electrical conductivity and carrier concentration characteristics), simultaneously addressing both requirements.
Solution Approach 2:
The patent employs a composite structure where the semiconductor layer is integrated with the capacitor electrodes. This composite approach combines the low power dissipation advantage of capacitive sensing with the magnetic field robustness of semiconductor materials, achieving both desired properties in a single integrated sensor structure.
3Measurement precision
If semiconductor layers with high dopant concentration are used, then temperature-dependent resistance changes are enhanced, but power dissipation increases
Solution Approach 1:
The patent substitutes resistance-based measurement with capacitance-based measurement. Although the semiconductor layer has temperature-dependent resistance, the sensor measures capacitance changes rather than resistance changes, allowing the use of semiconductor material properties without requiring continuous current flow that would cause power dissipation.
Solution Approach 2:
The patent changes the measurement parameter from resistance to capacitance. The semiconductor layer's temperature-dependent electrical characteristics are exploited through capacitance measurement, which can be performed with minimal power consumption, thus achieving temperature sensitivity without the power dissipation penalty of resistance-based sensing.
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 enables accurate temperature measurement with reduced power consumption and magnetic interference, enhancing the reliability of temperature sensors in various applications by utilizing a semiconductor layer with specific dopant concentrations and materials that change resistance significantly with temperature.
Implementation Method 1
a doped second layer portion with temperature-dependent resistance
Implementation Method 2
a semiconductor layer with specific dopant concentrations and materials that change resistance significantly with temperature
Data Source
AI summary
Temperature sensor devices and corresponding methods are provided. A temperature sensor may include a first layer being essentially non-conductive in a temperature range and a second layer having a varying resistance in the temperature range.