Research On Domain-Specific CMOS Temperature Sensor

Because of its low cost and high level of integration,CMOS temperature sensors are widely used in systems on chip.In addition to providing a digital temperature output for users,CMOS temperature sensors are also an important source of information for other complicated subsystems,such as real-time temperature compensation in precision clock circuits and high-speed interfaces,thermal monitoring and thermal management in multi-core processors,and RFID passive temperature sensing tags in wireless sensing networks,etc.Different application scenarios also put forward different performance requirements for temperature sensors.For example,real-time temperature compensation requires temperature sensors with high accuracy and fast transition time characteristics,on-chip temperature monitoring in multi-core processors emphasizes low-cost distributed temperature sensing units and centralized quantization schemes,and wireless sensing network applications have high requirements for power consumption and robustness.In response to the above performance requirements and challenges,this paper explores suitable temperature sensor architectures for these three types of application scenarios successively,and completes the design of domain-specific temperature sensors.The main work and innovation points of the paper are as follows:1.Research on temperature sensors based on high-resolution current comparators:(1)This paper proposes a new current-domain temperature sensor for temperature compensation needs of precise clock circuits and high-speed interfaces,using switched current comparators and dual-mode bucket search algorithms to provide a fast and low-cost readout mechanism;(2)For the characteristics of current-domain signals,this paper proposes a threshold setting technique to further improve the sensor’s accuracy(3)Combining the above innovations and precise circuit techniques such as dynamic element matching,this paper designs a compact,low-power,and,high-precision temperature sensor based on the SMIC 55nm CMOS process,which operates without any ADC or large charging capacitors,avoiding excessive area and power consumption.The conversion time of this temperature sensor also has a temperature difference-dependent characteristic,which can be reduced to 6.5for slow temperature change and continuous measurement.In the temperature range of-15～90℃,the temperature measurement accuracy is within±0.5℃after single-point calibration,and the area is only 0.0218)8)~2.2.Research on CMOS temperature sensor for thermal monitoring of multicore processors:(1)This paper proposes a compact temperature sensor specifically for temperature field monitoring of multicore processors,whose temperature-sensing node uses a self-biasing technique to push all transistors into the subthreshold region,with ultra-small area and ultra-low power consumption;(2)The differential cascade output scheme makes the temperature-sensing node free from noise interference,and the output signal of the temperature-sensing node is only related to the process-insensitive thermal voltage and the transistor size ratio,exhibiting extreme linearity and robustness under CMOS process deviations;(4)The layout of the temperature-sensing node is provided in the form of a digital standard cell,which can be integrated into the digital logic circuit automatic placement and routing flow with a high degree of compatibility.(5)Under the SMIC 55nm CMOS process,the temperature-sensing node designed in this paper occupies only 33.68)~2 area,and the maximum power consumption is only 12.39)(2 at 1(1.The simulated temperature measurement error is±0.6℃when the supply voltage changes from 0.4(1 to 1.8(1.Also at 1(1 supply voltage,the simulated temperature measurement error is±0.6℃.The simulation and measurement errors are+0.12℃/-0.02℃and+0.7℃/-0.45℃for temperature variations from-30～100℃at 1(1 supply voltage,respectively.3.Research on Temperature sensor based on leakage current ratio:(1)This paper proposes a time-domain temperature sensor that can be used for RFID,exploiting the exponential dependence of the leakage current ratio of different size transistors on temperature,with ultra-low power consumption and compact size;(2)The temperature sensor adopts a differential output scheme,and compared with other time domain temperature sensor designs,it can operate without an external regulator or precise clock generator,and the supply sensitivity is only 0.95℃/(1.(3)The time-domain temperature sensor designed in this paper is fabricated using a standard 55nm CMOS process,and the test results show that the design has a temperature measurement error of+0.8℃/-0.75℃in the temperature range of-20～80℃,and occupies only57008)~2 of silicon area.The power consumption is 2809)(2,and the conversion time is 378).