Temperature Sensor Digital Virtual Reference

Solution Overview

Problem

Conventional temperature sensors face inaccuracies due to induced offsets, component mismatches, and analog-to-digital conversion errors, which are exacerbated by unstable reference voltages, leading to increased production costs and restricted mass production capabilities.

Innovation Solution

A temperature sensor device that utilizes a digital virtual reference to calculate ambient temperature independently of reference voltage variations, incorporating an analog sensor to generate base-emitter voltage signals with complementary-to-absolute temperature characteristics, and an ADC to digitize these signals, thereby canceling out reference voltage and component mismatch errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If post-trimming procedure is employed to mitigate inaccuracies, then temperature sensor accuracy is improved, but production cost increases and mass production capability is restricted

Engineering Contradiction:

Improvetemperature sensor accuracyVSAvoidmass production capability

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent implements preliminary action by incorporating trimming circuitry during the manufacturing process rather than performing post-trimming after production. The trimming circuitry is integrated into the temperature sensor chip before packaging, allowing accuracy adjustment to be completed during fabrication rather than requiring separate post-production testing and adjustment steps.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies self-service by enabling the temperature sensor to perform its own trimming through integrated trimming circuitry that automatically adjusts calibration parameters. The sensor uses its own internal resources (power, signal paths) to conduct trimming operations without requiring external testing equipment or manual intervention, thereby eliminating the need for expensive post-trimming facilities.

Inventive Principle:

Principle #25Self-service

2Measurement precision

If post-trimming procedure is employed to mitigate inaccuracies, then temperature sensor accuracy is improved, but production cost increases

Engineering Contradiction:

Improvetemperature sensor accuracyVSAvoidproduction cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent implements preliminary action by incorporating trimming circuitry during the manufacturing process rather than performing post-trimming after production. The trimming circuitry is integrated into the temperature sensor chip before packaging, allowing accuracy adjustment to be completed during fabrication rather than requiring separate post-production testing and adjustment steps.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies self-service by enabling the temperature sensor to perform its own trimming through integrated trimming circuitry that automatically adjusts calibration parameters. The sensor uses its own internal resources (power, signal paths) to conduct trimming operations without requiring external testing equipment or manual intervention, thereby eliminating the need for expensive post-trimming facilities.

Inventive Principle:

Principle #25Self-service

3Adaptability or versatility

If analog circuitry with small signal-to-temperature gain is used, then temperature sensing function is achieved, but induced offsets and component mismatch result in substantial inaccuracies

Engineering Contradiction:

Improvetemperature sensing functionVSAvoidtemperature sensor accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent implements feedback by incorporating feedback paths that continuously monitor the temperature sensor output and adjust the trimming circuitry to compensate for induced offsets and component mismatches. The feedback mechanism dynamically corrects measurement errors by comparing actual output against expected values and automatically adjusting calibration parameters.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent applies mechanics substitution by replacing purely analog trimming mechanisms with a hybrid system that incorporates digital signal processing and microcontroller-based control. The microcontroller digitally adjusts calibration parameters rather than requiring physical analog component adjustment, thereby improving precision while maintaining the temperature sensing function.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 accurate temperature measurements that are immune to reference voltage variations and component mismatches, eliminating the need for post-trimming procedures, thus reducing production costs and enabling more efficient mass production.

Implementation Method 1

analog sensor to generate base-emitter voltage signals with complementary-to-absolute temperature characteristics

Methodology Applied

Scientific EffectComplementary-to-absolute temperature characteristics:

Data Source

PatentUS9389126B2Method and apparatus for low cost, high accuracy temperature sensor

Publication Date: 2016.07.12 ANALOG DEVICES INC

AI summary

The invention may provide a temperature sensor device that includes an analog temperature sensor to generate a first base-emitter voltage and a second base-emitter voltage, and an analog-to-digital converter (ADC) to sample at the voltages and generate corresponding digital values. The temperature sensor device may also include a logic unit to calculate a digital temperature code from the digital values using a digital virtual reference.