A Low-Power Mash Sigma-Delta Modulator with Digital Canceling Circuit for Biomedical Application

Chen-Ming Hsu ； Ho-Yin Lee ； Ching-Hsing Luo

《Journal of Medical and Biological Engineering》 27卷2期 (2007/06) Pp. 91-96

並列摘要

A low-power Multi-stAge noise SHaped (MASH) sigma-delta modulator (SDM) integrated with digital canceling circuit for biomedical application is presented in this paper. Fully differential switch-capacitor and single-bit quantization circuits are used to implement a fourth-order 2-2 MASH SDM. The proposed SDM has a chip digital canceling circuit so that it could be easily integrated with digital filter chip for biomedical application. The oversampling ratio of the proposed modulator is 128, with 4 kHz input signal bandwidth. Experimental results show the proposed SDM has 91.6dB signal-to-noise distortion ratio (corresponding to 15 bits resolution), and the power consumption is about 1.2 mW. Electrocardiogram signal can be actually acquired by proposed chip, proving the designed circuitry workable. The modulator has been designed and fabricated in TSMC 0.l8μm technology.

並列關鍵字

Sigma-delta modulator ； Low power ； Biomedical signal ； Analog-to-digital converter