| Summary: | 碩士 === 國立交通大學 === 生醫工程研究所 === 104 === Nowadays, the shortage of healthcare manpower becomes a serious problem due to the aging society and low birth rate. To solve the problem, the concept of wireless healthcare system is proposed. Implantable or portable monitoring system provides a personal health care and fast alarm by the cloud network to save professional manpower. The power consumption and chip’s area are two critical issues in portable or implantable healthcare system in order to function continuously within a limited area.
In this thesis, an output capacitor-less flipped voltage follower low dropout regulator and a low power wireless electrochemical sensing system are proposed. The proposed regulator removes the bulky output capacitor and the operational amplifier in conventional low dropout regulator design by flipped voltage follower technique with embedded bandgap reference. The proposed regulator achieves temperature coefficient 68ppm/oC over 0-100 oC with a PSR of -50dB. The quiescent current is 4.5 µA and the active area is 0.076mm2.
In wireless sensing system design, RF power and injection locking technique are adopted to avoid the bulky batteries and crystal resonators. In circuit design, an all CMOS voltage reference generator is proposed, and the time operation of sensing signal alternates the conventional voltage operation. Besides, the backscattering and envelope injection techniques solve the issue of large power consumption in wireless transmission and high frequency injection locking oscillator. The proposed system achieves a sensitivity of 289 Hz/nA and an R2 linearity of 0.997, and consumes 2.2 µW and can be powered by -12 dBm RF power with 1mm2 chip’s area. The proposed low-power techniques with no external components can be widely used in biomedical systems for disease diagnosis and biomarker analysis.
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