Biography
Enrollment Date: 2012
Graduation Date：2015
Degree：M.S.
Defense Date：2015.06.03
Advisors：Hanjun Jiang
Department：Institute of Microelectronics，Tsinghua University
Title of Dissertation/Thesis：Smart Body Temperature Detection Systems and Key Circuit Techniques
Abstract:
Body temperature is an important indicator of health status. The body temperature of children could help parents know whether the child is healthy or not. BBT (Basal Body Temperature) curve could guide female pregnancy, contraception effectively. So, it has great significance to detect and analysis children and women's body temperature conveniently and rapidly. People always put mercury thermometers, electronic thermometers or infrared thermometers on their armpit, mouth, ear or rectal for five to ten minutes when they want to know the body temperature. Without intelligent processing function and inconvenient to use, the conventional low accuracy temperature detection couldn't meet people's requirements any more.
In this paper, two solutions are presented to detect human body temperature. One is a band aid type of infant body temperature monitoring system, it contains a data collection terminal and a data read terminal. A RFID chip with voltage output and a low power temperature sensor are included in the data collection terminal, reading the data is realized by a NFC smart phone. The RFID chip, which provides power to the temperature sensor, gets energy from the 13.56MHz electromagnetic field, then sends temperature data to the smart mobile phone by wireless communication. The other is a BBT detection system. It is constituted by a low power microcontroller, a temperature sensor and a Bluetooth module. The BBT detection system could detect, record and analysis the temperature data conveniently.
It focuses on the design of the low power temperature sensor. The temperature sensor is realized in the standard 0.18μm CMOS process. Design, simulation, manufacture and test of the temperature sensor are all completed. The temperature sensor adopts 1.8V voltage supply. It comprises: the module of bandgap used for providing reference current and voltage, a temperature related oscillator, a constant pulse generator, a counter and the digital calibration module. This paper proposed a new structure, converting temperature signal to digital signal is fulfilled by counting the number of temperature related oscillator. The temperature sensor has low power consumption and high accuracy. The core circuit area is only 0.08mm2. The measurement accuracy is 0.2 degree after automatic calibration. The current consumption of the whole system is only 2 μA.
The band aid type of infant body temperature monitoring system provides a passive temperature detection method, it is convenient to detect the infant body temperature. Integrated with standard SPI communication interface, the temperature sensor, with low power consumption could be used in the above temperature monitoring system. The BBT detecting system could collect women's body temperature and give guidance to them. The above systems provide smart temperature detection method, and are convenient for family use.