Research And Design Of BJT Based Temperature Sensor

Temperature sensors have been largely applied to the industrial production and our life, traditionaltemperature sensors based on thediscrete passive components, such as the thermistor, have reached a very high precisionafter years of development,but they have inherent deficiencies, there is no direct data communication interface between them and the digital processing unitof the temperature measurement and control system. So, the integrated smart temperature sensorcompatible with standard CMOS processesbecome an important direction of development.In recent years, Radio Frequency Identification (RFID) technology has been rapid development, the combination of temperature sensors and RFIDbecome a new hotspot.Temperature sensors based on BJT have the highest precision in CMOS temperature sensors, which is accurate to ±0.1℃ overthe full military temperature range, but the power consumption is generally very high. High power consumption not only leads to self-heating of the temperature sensor, affect the temperature measurement, but also makes it difficult to integrate with RFID tags.In this paper, based on the theoretical analysis and calculation of the main error sources, error cancellation technologies such as chopping, DEM,βFcompensation are used to ensure the accuracy of the analog front end. And adopt a novel Zoom ADC based on a first-order ∑-Δ ADC which combine the merit of SAR ADC’s high speed and ∑-ΔADC’s high resolution, the Zoom ADC greatlyreducesthe requirement for the ENOB of ∑-ΔADC and thereby reduces the circuit complexity and power consumption. Finally accomplishthe schematic design and simulation in the SMIC 0.13μm mixed-signal process. The temperature sensoroperatesat 1.2 V, the static power consumption is 42μA,while the maximum dynamic power dissipation is 86.33μA,meets the requirement of low power, the measuring temperature range is from 0℃ to100℃, after a single digital trim at 50℃, it achieves aninaccuracy of ±0.5℃.