On-Chip Temperature Sensing Circuit With Analog BIST Feedback
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Solution Overview
Problem
Existing semiconductor integrated circuits face performance degradation and potential damage due to inaccurate temperature measurements, especially in critical applications like vehicle systems, where incorrect temperature information can impact safety.
Innovation Solution
A temperature measurement circuit is developed, incorporating a band-gap reference circuit, a reference voltage generator, a sensing circuit, an analog-digital converter, and an analog built-in self-test (BIST) circuit. This circuit generates a band-gap reference voltage, adjusts it to create a measurement reference voltage, and uses a sensing circuit to produce a temperature-variant voltage. The analog-digital converter converts these voltages into a digital code indicating the operation temperature, while the BIST circuit monitors the voltages to ensure they fall within predetermined ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If on-chip temperature sensors are integrated with semiconductor integrated circuits, then temperature monitoring capability is improved, but the risk of performance degradation or damage due to sensor failure increases
Solution Approach 1:
The temperature sensor includes a built-in self-test circuit that automatically monitors its own operation without requiring external test equipment. The self-test circuit generates test signals, measures sensor output, and detects failures autonomously, allowing the sensor to service itself and maintain reliability.
Solution Approach 2:
The self-test circuit creates a feedback mechanism where the sensor output is continuously monitored and compared against expected values. When the sensor output falls outside a predetermined range, the system receives feedback indicating potential failure, enabling corrective action before performance degradation occurs.
2Reliability
If built-in self-test circuit is added to temperature measurement circuit, then reliability is improved, but device complexity increases
Solution Approach 1:
The self-test circuit is merged with the temperature sensor circuit, sharing common components such as the sensing element, bias current sources, and signal paths. This integration allows the self-test functionality to be added without proportionally increasing overall circuit complexity, as test and normal operation share infrastructure.
Solution Approach 2:
The temperature sensor circuit is designed to serve multiple functions: normal temperature measurement and self-test operation. The same sensing elements and signal paths are used for both measurement and testing, eliminating the need for separate dedicated test components and reducing overall complexity.
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 proposed solution efficiently monitors and accurately measures operation temperatures in semiconductor integrated circuits, preventing performance degradation and potential damage. The built-in self-test functionality ensures that the temperature measurement circuit operates within normal ranges, enhancing reliability, especially in safety-critical applications.
Implementation Method 1
a band-gap reference circuit configured to generate a band-gap reference voltage that is fixed regardless of an operation temperature
Implementation Method 2
a sensing circuit configured to generate a temperature-variant voltage based on a bias current, where the temperature-variant voltage is varied depending on the operation temperature
Data Source
AI summary
A temperature measurement circuit includes a band-gap reference circuit configured to generate a band-gap reference voltage that is fixed regardless of an operation temperature, a reference voltage generator circuit configured to generate a measurement reference voltage by adjusting the band-gap reference voltage, a sensing circuit configured to generate a temperature-variant voltage based on a bias current, where the temperature-variant voltage is varied depending on the operation temperature, an analog-digital converter circuit configured to generate a first digital code indicating the operation temperature based on the measurement reference voltage and the temperature-variant voltage, and an analog built-in self-test (BIST) circuit configured to generate a plurality of flag signals indicating whether each of the band-gap reference voltage, the measurement reference voltage, and a bias voltage corresponding to the bias current is included in a predetermined range.