Research And Design Of Integrated CMOS Temperature Sensor

With the development of science and technology,high performance equipment has higher and higher requirements for temperature.CMOS temperature sensor can measure the temperature and feed back to the processor for temperature regulation.It is used in many electronic products,medical instruments and industrial fields.The pursuit of high precision,low power consumption and more intelligent temperature sensor is one of the research hotspots in the academic and industrial circles.For the system on chip,the increase of temperature is particularly obvious to the decline of system performance.It is necessary to use integrated CMOS temperature sensor to monitor the chip temperature for the reliability of the system.The work of this thesis is as follows:1.This thesis firstly introduces the basis of CMOS temperature sensor,including the physical characteristics and temperature characteristics of temperature sensing devices in standard CMOS technology,and introduces the implementation scheme of two kinds of temperature sensors according to the form of temperature sensitive signal generated by temperature sensing circuit,and designs two kinds of temperature sensors based on these two schemes.2.Firstly,based on 65 nm CMOS technology,a low power temperature sensor based on time domain is designed,including self-bias temperature sensing circuit based on allMOS tube,current starvation ring oscillator,frequency-digital conversion circuit simulation and layout rendering.After multi-point calibration of the temperature sensor’s post-imitation results,When the temperature measurement error is less than 1.7℃ in the temperature range of-40℃ to 140℃,the overall power consumption of the temperature sensor in the time domain is 23.5μW.The flow plate test of the temperature sensing circuit shows that the temperature sensing circuit can produce the frequency of positive temperature coefficient at 1V supply voltage,and the power consumption is 3.6μW.3.Finally,based on 65 nm CMOS technology,a high precision temperature sensor based on voltage domain is designed,including the simulation of front-end temperature sensing circuit,rail-to-rail chopper operational amplifier for improving driving capacity,and fully differential chopper temperature amplifier for amplifying temperature and voltage.Then,a 10 bit SAR ADC is designed for sampling temperature and voltage.The temperature and voltage were converted into digit code,and the circuit design and layout were completed.After two-point calibration,the temperature measurement error of the temperature sensor was less than 2℃ in the temperature range of-40℃ to 130℃,and the overall power consumption of the temperature sensor in the voltage domain was about670μW.The results show that the effective bits of the 10 bit SAR ADC and the front-end temperature sensing circuit are about 8.6bit,the transient power consumption is 405μW,and the front-end temperature sensing circuit can output the voltage with positive temperature coefficient.