For Full-Text PDF, please login, if you are a member of IEICE,|
or go to Pay Per View on menu list, if you are a nonmember of IEICE.
An Ultra-Low Power Variable-Resolution Sigma-Delta Modulator for Signals Acquisition of Biomedical Instrument
Chen-Ming HSU Tzong Chee YO Ching-Hsing LUO
IEICE TRANSACTIONS on Electronics
Publication Date: 2007/09/01
Online ISSN: 1745-1353
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Electronic Circuits
sigma-delta modulator, variable-resolution, ultra low power, biomedical,
Full Text: PDF>>
In this paper, an ultra-low power variable-resolution sigma-delta (ΣΔ) modulator for biomedical application is presented. The resolution of proposed modulator can be adjusted by switching its sampling frequency and architecture. The architecture is switched between second-order single-loop modulator and fourth-order cascaded second stage noise shaped modulator to reach different resolution requirement. The proposed sigma-delta modulator is implemented by single phase integrators based on a fully differential switched-capacitor circuit. The digital cancellation logic is embedded in the chip so that it would easily be integrated with biomedical instrument for effective acquisition. Experimental results of the proposed variable-resolution ΣΔ modulator fabricated in standard CMOS 0.18 µm technology confirm the expected specifications from 65 dB signal-to-noise distortion to 96 dB with 1 kHz bandwidth and power consumption range from 48 µW to 360 µW with a 1.8 V battery supply.