CMOS Temperature Compensation Circuit for Process Variation Errors
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Solution Overview
Problem
CMOS temperature sensors are susceptible to CMOS process deviations and channel length changes, leading to inaccurate temperature measurements.
Innovation Solution
A CMOS temperature compensator with constant current source modules, bias control, sampling, and processing modules to detect and average working voltage values, calculating reference and temperature corrected voltage values to compensate for process variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current difference between current mirrors is used for temperature sensing, then temperature measurement can be achieved, but measurement precision deteriorates due to CMOS process deviation and channel length changes
Solution Approach 1:
The patent divides the temperature sensing system into multiple independent constant current source modules, each with its own transistor and switch unit. This segmentation allows individual module calibration and independent error compensation, reducing the impact of overall process deviations on the final temperature measurement accuracy.
Solution Approach 2:
The patent introduces a processing module that dynamically adjusts operating parameters by selecting optimal working voltage values from multiple constant current source modules. The system changes parameters such as voltage selection and averaging weights to compensate for process deviations and achieve higher measurement precision despite manufacturing variations.
2Measurement precision
If multiple constant current source modules are used to reduce process deviation impact, then measurement precision improves, but device complexity increases
Solution Approach 1:
The constant current source modules are designed with multi-functionality, serving both as temperature sensing elements and as calibration references. The same modules used for temperature measurement also provide the basis for error compensation through their known voltage values, eliminating the need for separate calibration circuits and reducing overall device complexity.
Solution Approach 2:
The patent creates multiple copies of the constant current source circuit, each with identical structure but potentially different manufacturing variations. These copies are then processed and averaged to eliminate random errors, achieving high precision without requiring complex single-circuit designs.
3Measurement precision
If process deviation compensation is implemented, then measurement precision improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent implements a feedback mechanism where the processing module continuously monitors the working voltage values from multiple constant current source modules and adjusts the temperature calculation accordingly. This feedback loop compensates for manufacturing variations in channel lengths by using the actual measured voltages to correct the temperature reading, reducing the stringency of manufacturing precision requirements.
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 reduces errors caused by CMOS process deviations and package variations, improving temperature measurement accuracy and efficiency.
Implementation Method 1
the temperature detection module has a terminal electrically connected to the second transistor and another terminal which is electrically connected to processing module, for detecting a second working voltage value of the second transistor in a working status
Data Source
AI summary
Disclosed are a CMOS temperature compensator and its sensing method. The CMOS temperature compensator consists of multiple constant current source modules, a bias control module, a first voltage module, a sampling control module, a second transistor, a second voltage module, a temperature detection module and a processing module. The constant current source modules have a terminal connected to the first voltage module and another terminal connected to the second transistor and the temperature detection module. The processing module is connected to the temperature detection module and the sampling control module. The temperature detection module detects a second working voltage value of the second transistor according to the sensing method of CMOS temperature compensator, and converts it into first and second reference voltage values to obtain a temperature correction voltage value in order to correct the measured temperature, thereby reducing the mismatch problem and increasing the accuracy of temperature measurement.