Low Power Wireless Data Transmission for Implantable Neural Sensing Microsystems Application

• Main Authors: Chang, Feng-Kai, 張峰榿
• Other Authors: Chuang, Ching-Te
• Format: Others
• Language: en_US
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/7fyg56

碩士 === 國立交通大學 === 電子研究所 === 105 === This thesis, aims to design and implement a low power-consumption, less area, low process variation and temperature sensitivity to voltage controlled oscillator (VCO) and wide swing of output on wireless data transmission chip. The wireless data transmission system receives wireless data by the data which passes the OOK modulator, then it passes the inductive coupling via an on-interposer of receive terminal inductor which is out of the chip. Then it passes the OOK demodulator to recover the data. In this thesis, only the open-loop circuit is used to solve the problem that the oscillation frequency is drifted a lot by the process variation. The chip is used only all-MOS element, and we do not use any passive component on chip, rather than the general use of the special phase-locked loop to solve the problem, thus it can save a lot of power and area. In this thesis, the CMOS bandgap reference circuit is used to eliminate the MOS threshold voltage in the subthreshold region to reduce the VCO oscillation frequency deviation caused by the process variation. This method requires no additional compensation or calibration circuits. Hence it can reduce the area and the power of those circuits. Circuits operate in the subthreshold region can also reduce the power and operating voltage of the bias circuits. In this thesis, the purposed VCO with voltage reference provides stable current to oscillate at a fixed frequency against process and temperature variations, and the circuit is low power consumption, low area, and wide output swing design, and the purposed VCO with current reference is also less susceptible to against supply noise variation than the purposed VCO with voltage reference. We use the current-starved method and gain-boost method to against supply noise variation. In this thesis , the VCO and OOK modulator of wireless transmission chip are used differential input and differential output which can reduce the input signal noise, and increase the output swing. This thesis through the National Chip Implementation Center to tape out the chip with TSMC 180nm CMOS process. The simulation results show that the chip power consumption of the purposed wireless data transmission system with the purposed voltage reference is 382μW.The total area of the chip is 0.027 mm2.The oscillation frequency of the VCO is 256MHz.The variation of the VCO oscillation frequency is 4.3% at 0~50℃. The variation of the VCO oscillation frequency caused by the process variation is 29%. The chip power consumption of the purposed wireless data transmission system with the purposed current reference is 354μW.The total area of the chip is 0.036 mm2.The oscillation frequency of the VCO is 400MHz. The variation of the VCO oscillation frequency is 4.2% at 0~50℃. The variation of the VCO oscillation frequency caused by the process variation is 27%. The variation of the VCO oscillation frequency caused by the supply variation at plus or minus 10% supply variation is 3.3%.