A Low Power Energy-Efficient Precision CMOS Temperature Sensor ^†

Area of Science:

• Electrical Engineering
• Integrated Circuit Design
• Sensor Technology

Background:

• Accurate temperature sensing is crucial for many electronic systems.
• Existing sensors often face challenges with power consumption and measurement accuracy.
• CMOS technology offers a scalable platform for developing efficient sensor solutions.

Purpose of the Study:

• To develop a low-power, energy-efficient, and high-precision CMOS temperature sensor.
• To address measurement errors caused by current ratio mismatch.
• To achieve high accuracy over an extended temperature range.

Main Methods:

• Utilized a front-end circuit based on bipolar junction transistors with a pre-bias circuit and bipolar core.
• Implemented a novel dynamic element-matching mode to mitigate current source mismatch.
• Employed first-order and third-order fitting for output calibration.
• Designed and simulated the sensor using 0.18 μm CMOS technology.

Main Results:

• Simulated sensor achieved 3σ inaccuracies of +0.18/-0.13 °C from -55 °C to +125 °C.
• Measured sensor demonstrated 3σ inaccuracies of ±0.2 °C from 0 °C to +100 °C.
• The circuit operates at a low power consumption of 6.1 μA with a 1.8 V supply.

Conclusions:

• The developed CMOS temperature sensor offers excellent accuracy and energy efficiency.
• The dynamic element-matching technique effectively reduces measurement errors.
• The sensor is suitable for applications requiring precise temperature monitoring with minimal power usage.