Temperature Sensor With Segmented Diodes For Precision
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Solution Overview
Problem
Temperature sensors using PN junction diodes face challenges in accurately detecting temperature due to manufacturing errors that can deviate the saturation current, leading to inaccuracies in temperature measurement.
Innovation Solution
A temperature sensor configuration that includes a diode for temperature detection, a current supply circuit to provide different evaluation currents, an amplifying circuit to generate amplified voltages from these currents, and a reference voltage generation circuit using a reference diode to calculate temperature independently of saturation current deviations, allowing for precise temperature measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single diode is used for temperature detection, then the device complexity is low, but manufacturing errors cause saturation current deviation leading to poor measurement precision
Solution Approach 1:
The patent divides the temperature detection function into multiple independent diodes (first diode and second diode) with different characteristics. The first diode has a first saturation current and the second diode has a second saturation current, allowing independent measurement of temperature effects while compensating for manufacturing variations. This segmentation enables the system to distinguish between temperature-induced changes and manufacturing errors.
Solution Approach 2:
The patent creates a copy of the temperature detection diode (second diode) with intentionally different saturation current characteristics. This copy serves as a reference that experiences the same temperature changes but with different current characteristics, enabling the system to calculate temperature effects independently of the specific diode's manufacturing variations through ratio-based measurements.
2Measurement precision
If different evaluation currents are supplied to the diode at different timings, then temperature detection accuracy is improved by isolating saturation current effects, but the device complexity and operation time increase
Solution Approach 1:
The patent employs periodic switching of evaluation currents through time-multiplexed measurement. The current supply circuit alternates between supplying a first evaluation current to the first diode and a second evaluation current to the second diode in sequential periods. This periodic action allows the system to capture voltage characteristics at different current levels, enabling calculation of temperature effects while maintaining manageable circuit complexity through time-sharing.
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 configuration enables accurate temperature detection by isolating the effect of saturation current deviations, maintaining high resolution and keeping the amplified voltage within the dynamic range of the ADC, thus improving the reliability and precision of temperature measurement.
Implementation Method 1
Temperature sensors performing temperature detection by using PN junction diodes are extensively used. When a forward current is supplied to a diode, a forward voltage is generated in the diode, and the forward voltage has a negative temperature coefficient.
Implementation Method 2
an amplifying circuit, configured to amplify a difference voltage between the diode forward voltage and a reference voltage to generate an amplified output voltage
Data Source
AI summary
The present disclosure provides a temperature sensor. The temperature sensor includes: a temperature detection diode, disposed at a position having a target temperature; a current supply circuit, configured to supply a first evaluation current and a second evaluation current to the temperature detection diode in a forward direction of the temperature detection diode at different timings; an amplifying circuit, configured to generate a first amplified voltage and a second amplified voltage by amplifying a difference between a forward voltage of the temperature detection diode and a reference voltage when the first and second evaluation currents are supplied to the temperature detection diode; a temperature detection circuit, configured to detect the target temperature based on the first and second amplified voltages; and a reference voltage generation circuit, configured to include a reference diode disposed at a position having a temperature corresponding to the target temperature.