Bandgap Temperature Sensor Parasitic Error Cancellation
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Solution Overview
Problem
Conventional bandgap reference temperature sensors face challenges in accuracy due to errors from non-ideal component behavior, parasitic resistance, and mismatch issues, requiring substantial post-processing to correct temperature output.
Innovation Solution
A temperature detection system generates a signal proportional to temperature from three samples, where the signal is defined as a difference between a first difference and a second difference, with the first difference comprising a difference between the second sample and the first sample, and the second difference comprising a difference between the third sample and the first sample, to cancel parasitic components in the samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional bandgap reference temperature sensor is used, then temperature detection function is provided, but accuracy is reduced due to parasitic resistance errors and non-ideal component behavior
Solution Approach 1:
The temperature sensor is divided into multiple identical sub-sensors (first temperature sensor, second temperature sensor, third temperature sensor) that each produce separate output signals. This segmentation allows individual measurement of parasitic effects in each sensor, which can then be mathematically eliminated through differential processing, thereby improving temperature accuracy while compensating for parasitic resistance errors.
2Measurement precision
If post-processing correction is applied to conventional temperature sensor, then temperature accuracy is improved, but device complexity increases
Solution Approach 1:
The system performs preliminary measurement of parasitic resistance effects by utilizing the output signals from multiple identical temperature sensors before the final temperature calculation. The differential processing unit预先 captures the parasitic components in separate measurements, allowing these to be subtracted out in subsequent processing. This preliminary characterization of errors simplifies the overall correction process compared to attempting to model and correct all non-ideal behaviors simultaneously.
3Power
If current density is increased to improve conversion gain, then conversion gain is improved, but parasitic resistance errors increase
Solution Approach 1:
The system creates multiple copies of the temperature sensor (first, second, and third temperature sensors) with identical characteristics. By measuring the same physical quantity through multiple identical pathways, the system can separate the true temperature signal from parasitic resistance errors through differential processing. This copying approach allows accurate temperature measurement without requiring high current density that would exacerbate parasitic effects.
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 approach improves temperature accuracy and increases conversion gain without increasing current density, effectively reducing parasitic resistance errors and other issues common in conventional bandgap reference temperature sensors.
Implementation Method 1
Silicon PN junction sensors... A bandgap reference temperature sensor is a type of Silicon PN junction sensor
Data Source
AI summary
Temperature accuracy is improved, conversion gain is increased without increasing current density and parasitic resistance errors and other problems with conventional bandgap reference temperature sensors are eliminated by generating a signal proportional to temperature from three samples, where the signal is defined as a difference between a first difference and a second difference, the first difference comprising a difference between a second sample and a first sample, the second difference comprising a difference between a third sample and the first sample, and where the signal is defined to cancel parasitic components in the first, second and third samples.