Design Of Low Power CMOS Temperature Sensor

With the advancement of process manufacturing technology,circuit integration density is getting higher and higher,power consumption is increasing rapidly,temperature detection and monitoring to prevent circuit overheating has become an indispensable part of circuit design.For equipment used in environments with high-precision requirements,temperature will bring errors that cannot be ignored,such as high-precision meters and clocks.In the medical field,the human body temperature measuring instrument is a medical instrument with extremely high application frequency.In addition,for temperature sensors with high power consumption,the temperature sensor circuit itself generates serious heat,which will cause the temperature value detected by the temperature detection device to have a large deviation from the actual temperature value that needs to be detected.And with the rapid development of portable devices and wearable smart devices,the demand for low power consumption of chips is increasing,so the design of low power CMOS temperature sensors is extremely important.This paper designs a low-power CMOS temperature sensor under the 130 nm CMOS process,which mainly includes a temperature sensing module and a temperature quantization module.The temperature sensing module utilizes the temperature characteristics of the negative temperature coefficient of the gate-source voltage of the MOSFET working in the sub-threshold region.Because it works in the sub-threshold region,it has the advantage of low power consumption.This paper proposes a temperature sensing circuit structure that is simple and can obtain a positive temperature coefficient voltage and a negative temperature coefficient voltage.The difference between the two voltages is used as the temperature detection voltage,and compared with a single temperature coefficient voltage,which variation range with temperature increases.The temperature quantization module adopts an analog-digital converter(Analog Digital Converter,ADC),and the temperature-sensing module generates an analog voltage signal with a temperature coefficient,which is converted into a digital signal with a temperature coefficient through the ADC.This paper designs a 10 bits fully differential successive approximation(SAR)ADC.In order to reduce power consumption,the comparator module uses a time domain comparator based on a Voltage Controlled Oscillator(VCO);The switch timing module analyzes the DAC array's switch timing and the DAC array in the ADC,and proposes the terminal capacitor multiplexing capacitor switch timing based on it.The power supply voltage is 0.6V,the reference voltage Vref is 0.6V,the sampling frequency is 50 k Hz.The simulation results show that the effective number of bits is about 9.94 bit,the SFDR is 76.80 d B,and the power consumption is about 0.64?W.Finally,the analog voltage signal output by the temperature sensing module is quantified by the temperature quantization module,and the temperature error of the low-power temperature sensor is ? 0.1? in the temperature range 35?-42?,and the total power consumption is 0.7?W.