The Design Of CMOS Temperature Sensor With Zoom-ADC

As an important part of the sensors,temperature sensors are widely used in medical detection,industrial control,and civil life.In the occasion where high accuracy is required such as clocks and meters,the measurement error by reason of the ambient temperature change can't be ignored,the temperature sensors must be used to obtain the ambient temperature for temperature compensation,high-accurate sensors are required.At the same tiome,information can be efficiently and conveniently transferred and processed because of the characteristics of high energy efficiency,miniaturization and digital output in CMOS temperature sensors,therefore,a high-accurate CMOS temperature sensor that can be used in temperature compensation systems is designed.This thesis is started from physical characteristics of CMOS substrate parasitic BJT devices,the temperature measurement principle of PNP transistors is described,and the working principle and performance characteristics of the??-ADC which is commonly used in temperature sensors is introduced in detail.In order to improve the accuracy of temperature measurement,digital curvature correction technology is adopted to reduce the temperature measurement error by the nonlinear temperature characteristics of the base-emitter voltage(1_BE of the PNP transistor,and digital temperature calibration,chopper amplifier,_F compensation circuit and dynamics matching current mirror are designed to reduce the temperature measurement error by the device process spread.In order to solve the contradiction between effective number of bits and conversion time of the first-order??-ADC,a two-stage zoom analog-to-digital converter?Zoom-ADC?that combines a 5-bit SAR-ADC with an 8-bit??-ADC is designed,and a switched capacitor integrator with excellent noise immunity further improve the temperature measurement accuracy.Based on circuit principle analysis and module design,the design and simulation of the temperature sensor circuit and layout are completed based on the 0.13?m CMOS process in the Candence integrated environment,the occupied area of layout is 0.075mm².The post-simulation results show that an inaccuracy of-0.32?⁰.35?from-40?to 85?is achieved,while a resolution of 0.03?is achieved within the conversion time of 42ms,at the lowest working voltage of 1.6V,it draws 7.9?A at room temperature?25°C?,in the full temperature range,the operating current does't exceed 10?A,high accuracy is achieved with lower power consumption.