The precision amplifier circuits design and sensor module application

• Main Authors: chia li yu, 游佳理
• Other Authors: yu wen chen
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/53031587574592052717

碩士 === 萬能科技大學 === 工程科技研究所 === 98 === We propose three precise types of analog sense amplifiers and compare both their merits and disadvantages. First, we design a fully differential operational amplifier including stable voltage source circuit, and common-mode feedback circuit (CMFB). Second, we design two-stage CMOS operational amplifier and instrumentation amplifier, and analyze the circuit characteristics. With a 5V power supply, the two-stage CMOS operational amplifier which the open loop gain can achieve 65dB, the gain bandwidth is 3.75MHz, the input offset voltage is 0.1mV and the output voltage swing is nearly close to rail to rail type. The instrumentation amplifier input impedance is about infinity. A good performance of the common mode rejection ratio (CMRR) of the fully differential operational amplifier is about 93dB. The average input offset voltage of all three proposed sensing amplifiers are smaller than 10mV. These precision amplifiers were fabricated by using MXIC 0.5 micron power CMOS 2P3M 5V/18V process. The application of these sensor amplifiers are implemented to measure pressure, curvature, and distance. The output signals are transferred to digital data with analog-digital converter and show in the seven-segment display on digital development platform. We adopt the look-up table method to decode and fine tune to match the non-linear characteristics of different cases. After adopting correction algorithm, the non-linearity sensing curve shows good performance with the error percentage less than 5% compared to the actual value.