Low Power Analog-to-Digital Converter and Super-Regenerative Receiver for Bio-Medical Applications

• Main Authors: You-Kuang Chang, 張祐匡
• Other Authors: Chorng-Kuang Wang
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/61131784989171681706

碩士 === 國立臺灣大學 === 電子工程學研究所 === 95 === As the emerging of the bio-MEMS and wireless technology, the implantable bio-medical system becomes a popular research topic. The primary challenge is how to reduce power consumption of the system. Low power operation is essential for any implanted bio-medical system as the heat spread by the circuits will increase local temperature which may damage our organs and neurons. This thesis presents a low power successive-approximation-register analog-to-digital converter (SAR ADC) and a low power super-regenerative receiver for bio-medical applications. In this 8-bit SAR ADC, an energy-saving switching sequence technique is proposed to achieve low power consumption. The average switching energy of the capacitor array can be reduced by 56% compared to a conventional switching sequence. The measured signal-to-noise-and-distortion ratios of the ADC is 46.92 dB at 500KS/s sampling rate with an ultra-low power consumption of only 7.75-μW from a 1-V supply voltage. The ADC is fabricated in a 0.18-μm CMOS technology. A low-power super-regenerative receiver for 915MHz ISM band is also presented. The super-regenerative oscillator which is the core of the receiver is quenched by a 5-bit DAC and therefore the selectivity of the receiver can be controlled precisely. Furthermore, operating the MOS in sub-threshold region lowers the power consumption of the receiver. The simulation results show that the receiver consumes 0.8mW for a sensitivity of -90dBm and data rate of 1Mbps at 1-V supply voltage in a 0.18-μm CMOS technology.