高性能之金氧半電晶體臨界電壓溫度感測器

A HIGH PERFORMANCE THRESHOLD VOLTAGE BASED TEMPERATURE SENSOR

王彥婷(YEN-TING WANG)

指導教授 ： 黃淑絹

大同大學/電機資訊學院/電機工程學系所/碩士(2010年)

摘要

一個數位輸出的溫度感測系統包括了前端的溫度感測電路、參考電壓源，以及後端的類比數位轉換器。本文探討溫度感測系統前端部分的設計並以七位元快閃式類比數位轉換器實現完整架構，系統前端部分以CMOS電晶體之臨界電壓來感測電路溫度變化，並配合傳統正比絕對溫度電流產生器電路來完成溫度低敏感參考電壓源，以提供類比數位轉換器使用之參考電壓。電路模擬是使用1.8伏特及台積電公司的0.18um CMOS 的標準製程參數並用HSPICE軟體完成模擬分析。
此溫度感測電路在-20°C～100°C的溫度範圍內，模擬顯示能產生一個不受電壓源影響並正比於溫度的感測輸出電壓，其隨溫度的變化率為-1.239mV/℃，線性度誤差為±0.07℃。低溫度敏感參考電壓則為1.51V，溫度係數為1.058ppm/℃，因此此參考電壓幾乎不受溫度影響。七位元快閃式類比數位轉換器之積分非線性誤差為0.32 LSB微分非線性誤差則為0.38 LSB，是用於解析度為1°C之溫度感測系統。

關鍵字

感測器

並列摘要

A smart temperature sensing system with digital output consists of a temperature sensor and a voltage reference in the front end and an analog-to-digital converter (ADC) in the back end. In this thesis, a threshold-voltage based temperature sensor has been presented, and a low temperature coefficient voltage reference is achieved by using a pn-junction proportional to absolute temperature (PTAT) current generator to compensate the threshold-voltage based temperature sensor. In addition, a 7-bit flash ADC has been designed to convert the output of the temperature sensor to a digital code. The simulation results obtained from HSPICE using a standard TSMC 0.18um CMOS models and 1.8V power supply are presented in this thesis.
This sensor is almost insensitive to the supply and is very linear dependent to temperature. The simulation result shows that the voltage output of the sensor has the temperature error of ±0.07°C from -20°C～100°C, and temperature coefficient of it is -1.239 mV/°C. The low temperature coefficient voltage reference has the result of 1.51V, and the temperature coefficient is 1.058ppm/°C. The 7-bit flash bit has the INL of 0.32LSB, and DNL of 0.38LSB, which can meet the requirement of the temperature sensing system with 1°C resolution.

並列關鍵字

sensor

參考文獻

[1] K. E. Kujik, “A precision reference voltage source,” IEEE Journal of Solid-State Circuits, vol. SC-8, pp. 222-226, Jun. 1973.

[4] P. Chen, C.C. Chen, A.W. Liu, W.F. Lu, and C.C. Tsai, “A time- to-digital-converter-based CMOS smart temperature sensor,” IEEE J. Solid-State Circuits, vol. 40, no. 8, pp. 1642-1648, Aug. 2005.

[5] P. Chen, C.C. Chen, and Y. S. Shen, “A low-cost low-power CMOS Time-to-Digital Converter Based on Pulse Stretching,” IEEE Trans. Nucl. Sci., vol. 53, no. 4, pp. 2215-2220, Aug. 2006.

[6] C.C. Chen, P. Chen, A.W. Liu, W.F. Lu, and Y.C. Chang, “An Accurate CMOS Delay-Line-Based Smart Temperature Sensor for Low-Power Low-Cost Systems,” Meas. Sci. Technol., vol. 17, no 4, pp. 840-846, Apr. 2006.

[8] B.S. Song and P.R Gray, “A precision curvature compensated CMOS bandgap reference,” IEEE Journal of Solid-State Circuits, vol.18, pp. 634-643, Dec.1983.