A Design Of Analog Integrated Temperature Sensor Using CMOS Technology

Although both MOS and bipolar transistors have properties that could be used for temperature sensing, the latter has shown much better performance for this purpose. This fact explains why up to now bipolar solutions were preferred. Since CMOS is still the most extensively used technology, the integration of temperature sensors in CMOS technologies is preferred to allow signal conditioning and digital processing on the same chip. However, the existing CMOS-compatible temperature sensors still suffer from a number of specific problems such as offset, drift and process variations, so research of CMOS-compatible temperature sensors with high-accuracy, low-power, low-cost becomes a important subject.In this paper a high-accuracy CMOS temperature sensor is presented. In order to assure the circuit's normally operation and good accuracy, ESD and Start-up circuit are designed. This circuit focuses on the achievements of easy-structure, low-voltage, high-PSRR and good-linearity, etc. HSPICE simulation approves that its PSRR can achieve 64dB, the voltage-temperature coefficient under temperature of -50℃～150℃can achieve 2.9mV/K, and its linearity is also good.Based on the research achievements, a curvature alter circuit used to adjust CMOS integrated temperature sensor's quadratic non-linear term is presented. This circuit can solve the phenomena that resist temperature coefficient and PN junction voltage's quadratic non-linear term influence output's linearity. This temperature sensor has been realized under 0.6μm CMOS process. Testing result shows that the max error under temperature of -50℃～150℃can below 1.5℃.The research achievements can be used for some high accuracy applications, just as cold-warm air condition, medicine instrument and self-checking systems, etc. In a word, it has a significant research meaning and extensive application prospect.