A 135-μW 0.46-mΩ/√Hz thoracic impedance variance monitor with square-wave current modulation

Author

Chih-Chan Tu ; Feng-Wen Lee ; Dong-Feng Yeih ; Tsung-Hsien Lin

Author_Institution

Nat. Taiwan Univ., Taipei, Taiwan

fYear

2014

fDate

10-12 Nov. 2014

Firstpage

305

Lastpage

308

Abstract

A low-power high-resolution thoracic impedance variance (TIV) monitoring circuit is presented. The TIV information is extracted by injecting a square-wave modulated current to the body. The resulted voltage is then demodulated by a proposed delayed-sampling technique. This proposed technique solves the gain-error issue occurred in prior square-wave modulated architectures. Furthermore, compared with sine-wave modulation, the proposed TIV monitoring circuit is more power efficient. Fabricated in a 0.18-μm CMOS, this chip draws 75 μA from a 1.8-V supply. The equivalent input-referred impedance noise density is only 0.46 mΩ/VHz.

Keywords

CMOS integrated circuits; biomedical electronics; electric impedance imaging; low-power electronics; modulation; CMOS; TIV information; current 75 muA; delayed-sampling technique; gain-error issue; low-power high-resolution TIV monitoring circuit; low-power high-resolution thoracic impedance variance monitoring; power 135 muW; size 0.18 mum; square-wave modulated current; voltage 1.8 V; Current measurement; Demodulation; Immune system; Impedance; Monitoring; Noise;

fLanguage

English

Publisher

ieee

Conference_Titel

Solid-State Circuits Conference (A-SSCC), 2014 IEEE Asian

Conference_Location

KaoHsiung

Print_ISBN

978-1-4799-4090-5

Type

conf

DOI

10.1109/ASSCC.2014.7008921

Filename

7008921