IC Temperature Sensor Using Differential Diode Voltages
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Solution Overview
Problem
Existing temperature sensors in integrated circuits have a large number of electronic components that introduce non-linearities, making them inaccurate and requiring complex and costly calibration processes.
Innovation Solution
An integrated circuit with a temperature sensor comprising two diode-connected transistors of different sizes, a buffer circuit, a switching circuit, and an analog-to-digital converter that calculates a voltage difference proportional to absolute temperature, independent of offset voltages, allowing for simple calibration and low-cost manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a large number of electronic components are used in the temperature sensor, then the sensor can perform multiple functions and provide comprehensive temperature measurement capabilities, but the non-linearities accumulate and impact the accuracy of the temperature sensor
Solution Approach 1:
The patent extracts only the essential components needed for temperature measurement (two diode-connected transistors with different sizes) and removes unnecessary electronic components that introduce non-linearities. This minimalistic approach maintains temperature measurement functionality while eliminating sources of measurement error.
Solution Approach 2:
The patent changes the key parameter from the absolute voltage values to the difference between voltage values generated by two transistors of different sizes. This parameter transformation eliminates offset voltages and reduces the impact of non-linearities, thereby improving measurement precision.
2Measurement precision
If the temperature sensor is calibrated to improve accuracy, then the measurement precision is improved, but the calibration process becomes time-consuming and complex
Solution Approach 1:
The temperature sensor structure inherently compensates for offset voltages and minimizes non-linearities through the differential measurement approach. This self-compensating design reduces the need for external calibration procedures, making the sensor nearly calibration-free and significantly reducing calibration time and complexity.
3Ease of manufacture
If offset voltages are present in the buffer circuit and analog-to-digital converter, then the measurement system remains simple and low-cost, but the accuracy of voltage measurements is reduced
Solution Approach 1:
The patent transforms the measurement parameter from absolute voltage to voltage difference, which mathematically eliminates the effect of offset voltages in the buffer circuit and ADC. This allows the use of simple, low-cost components without sacrificing measurement accuracy.
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 temperature sensor achieves high accuracy by eliminating offset voltages and minimizing the impact of non-linearities, enabling quick and cost-effective calibration and manufacturing.
Implementation Method 1
two diode-connected transistors having different sizes... calculate a numeric value corresponding to a difference between the numeric values of the voltages generated across the two transistors, this difference in voltages being proportional to absolute temperature
Data Source
AI summary
An integrated circuit temperature sensor includes two diode-connected bipolar transistors having different sizes. A switching circuit selectively applies the base-emitter voltages generated across the two diode-connected bipolar transistors to the input of a buffer circuit. A control unit controls alternate switching by the switching circuit. An analog-to-digital converter has an input connected to an output of the buffer circuit. The analog-to-digital converter calculates a numeric value corresponding to a difference between the voltages generated across the two diode-connected bipolar transistors, this difference in voltages being proportional to absolute temperature.