Hybrid Thermistor-Diode Circuit for Parasitic-Resistant Temperature Sensing

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Solution Overview

Problem

Existing resistance-based temperature sensors face challenges in accurately inferring local temperatures due to parasitic effects from external interconnections, which introduce parasitic resistances that complicate resistance measurements.

Innovation Solution

A temperature sensor design utilizing a diode/resistor hybrid circuit with adjacent thermistors of the same material but different geometric dimensions and diodes of opposite polarities, allowing for parasitic resistance elimination by changing voltage polarity to measure resistance differences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If resistance-based temperature sensing is used to infer local temperature, then the temperature measurement is simple and practical with good linearity, but parasitic resistances from external interconnections are introduced that compromise measurement accuracy

Engineering Contradiction:

Improvesimplicity of temperature sensingVSAvoidaccuracy of temperature measurement

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The sensing circuit is segmented into multiple independent voltage sources (V1, V2, V3, V4) and measurement paths. By applying different voltage polarities sequentially and measuring through separate paths, the parasitic resistance Rc is isolated and eliminated from the temperature measurement, allowing accurate determination of RT without external interconnection errors

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the polarity parameter of the applied voltage between measurement cycles. By switching between positive and negative voltage polarities and measuring the corresponding resistance values, the system can mathematically eliminate the parasitic resistance component and extract the true thermistor resistance for accurate temperature sensing

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If external interconnections are used to connect the thermistor to measurement equipment, then the sensor can be integrated into the system, but parasitic effects are introduced that complicate the resistance measurement

Engineering Contradiction:

Improveintegrability of sensor into systemVSAvoidparasitic effects from interconnections

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The invention converts the harmful parasitic resistance effect into a measurable parameter. By using differential measurements with reversed voltage polarities, the parasitic resistance Rc becomes a consistent offset that can be mathematically subtracted, transforming the harmful interconnection effect into a correctable measurement artifact

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The system uses feedback through sequential voltage polarity switching and corresponding resistance measurements. The measured resistance values under different polarity conditions provide feedback information that enables calculation and elimination of the parasitic resistance component, achieving accurate temperature measurement despite external interconnections

Inventive Principle:

Principle #23Feedback

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 design enhances temperature measurement accuracy by eliminating parasitic resistances, ensuring precise temperature detection independent of interconnect parasitics.

Implementation Method 1

two adjacent thermistors with a same material and process, but different geometric dimensions

Methodology Applied

Scientific EffectTemperature coefficient of resistance: Thermistor

Implementation Method 2

the first diode and the second diode are two adjacent diodes with a same type, but opposite polarities

Methodology Applied

Scientific EffectDiode rectification: Diode

Data Source

PatentUS20250383242A1Temperature Sensor, Temperature Sensor Packaging Method, and Temperature Measurement Method

Publication Date: 2025.12.18 SANECHIPS TECH CO LTD

AI summary

A temperature sensor comprises: a first thermistor, a second thermistor in parallel connection with the first thermistor, a first diode in serial connection with the first thermistor, and a second diode in serial connection with the second thermistor, wherein the first thermistor and the second thermistor are two adjacent thermistors made of the same material and process but having different geometric dimensions, and the first diode and the second diode are two adjacent diodes of the same model but opposite polarities. Further disclosed are a temperature sensor packaging method and a temperature measurement method.