J. Semicond. > 2015, Volume 36 > Issue 10 > 105005
|

SEMICONDUCTOR INTEGRATED CIRCUITS

Demonstration of a fully differential VGA chip with small THD for ECG acquisition system

Gongli Xiao1, 2, Yuliang Qin1, Weilin Xu1, , Baolin Wei1, Jihai Duan1 and Xueming Wei1

+ Author Affiliations

 Corresponding author: Weilin Xu, xwl@guet.edu.cn

DOI: 10.1088/1674-4926/36/10/105005

PDF

Abstract: We present both a theoretical and experimental demonstration of a fully differential variable gain amplifier (VGA) with small total harmonic distortion (THD) for an electrocardiogram (ECG) acquisition system.Capacitive feedback technology is adopted to reduce the nonlinearity of VGA.The fully differential VGA has been fabricated in SMIC 0.18-μm CMOS process, and it only occupies 0.11 mm2.The measurements are in good agreement with simulation results.Experimental results show that the gain of VGA changes from 6.17 to 43.75 dB with a gain step of 3 dB.The high-pass corner frequency and low-pass corner frequency are around 0.22 Hz and 7.9 kHz, respectively.For each gain configuration, a maximal THD of 0.13% is obtained.The fully differential VGA has a low THD and its key performance parameters are well satisfied with the demands of ECG acquisition system application in the UWB wireless body area network.

Key words: fully differential VGA, total harmonic distortion, ECG acquisition system, capacitive feedback



[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
[15]
[16]
[17]
s 1.  (a) Block diagram of the VGA system which including 4bit decoder,switched capacitor array $C_{1}$,and full differential OTA. (b) Microphotograph of the proposed VGA and test setup.

DownLoad: Full-Size Img PowerPoint
s 2.  (a) The corresponding equivalent small signal schematic. (b) The transmission model of the fully differential VGA.

DownLoad: Full-Size Img PowerPoint
s 3.  Simulation results including (a) the frequency response,(b) the maximal HD3 of all gain configurations,and (c) (color online) transient scan results with gain spans from 7 to 46 dB.

DownLoad: Full-Size Img PowerPoint
s 4.  Measurement of the frequency response.

DownLoad: Full-Size Img PowerPoint
s 5.  Measurement of the output power spectrum.

DownLoad: Full-Size Img PowerPoint
s 6.  The measurement of the ECG amplified by the VGA with (a) gain configuration of 6.18 dB and (b) gain configuration of 9.20 dB. The oscilloscope screenshot shows the VGA output voltage on CH2 and input voltage on CH1.

DownLoad: Full-Size Img PowerPoint

Table 1.   Measured performance summary in comparison with other works.

Parameter This work Reference [6] Reference [10] Reference [13] Reference [14]
CMOS process ($\mu$m) 0.18 0.35 0.35 0.35 0.18
Supply voltage (V) 1.8 $\pm$ 1.5 1 1 1
Power consumption ($\mu $W) 39 280 0.34 3.77 18
Gain range (dB) 6.18-43.55 10-62 45.6/49/53.5/60 45.7/49.3/53.7/60.5 8-58
Gain step (dB) 3 Continuous 3 3 6
High-pass corner (Hz) 0. 22 N/A 0.0045-3.6 0.23-217 0.015
Low-pass corner (kHz) 7.9 20 0.031-0.292 7.8 0.1-2
THD (%) 0.13
(at output $>$ 900 mV)		 0.89
(at output< 900 mV)		 0.55-0.1
(at output< 900 mV)		 0.2-0.3
(at output< 900 mV)		 0.65
Chip area (mm$^{2})$ 0.11 0.064 N/A 0.171 N/A
DownLoad: CSV
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
[15]
[16]
[17]

    • Search

    Advanced Search >>

    GET CITATION

    shu

    Export: BibTex EndNote

    Article Metrics

    Article views: 2963 Times PDF downloads: 21 Times Cited by: 0 Times

    History

    Received: 03 February 2015 Revised: Online: Published: 01 October 2015

    Catalog

      Email This Article

      User name:
      Email:*请输入正确邮箱
      Code:*验证码错误
      Send
      Article Navigation >  Journal of Semiconductors  > 2015  >  36(10): 105005
      Gongli Xiao, Yuliang Qin, Weilin Xu, Baolin Wei, Jihai Duan, Xueming Wei. Demonstration of a fully differential VGA chip with small THD for ECG acquisition system[J]. Journal of Semiconductors, 2015, 36(10): 105005. doi: 10.1088/1674-4926/36/10/105005 ****G L Xiao, Y L Qin, W L Xu, B L Wei, J H Duan, X M Wei. Demonstration of a fully differential VGA chip with small THD for ECG acquisition system[J]. J. Semicond., 2015, 36(10): 105005. doi: 10.1088/1674-4926/36/10/105005.
      Citation:
      Gongli Xiao, Yuliang Qin, Weilin Xu, Baolin Wei, Jihai Duan, Xueming Wei. Demonstration of a fully differential VGA chip with small THD for ECG acquisition system[J]. Journal of Semiconductors, 2015, 36(10): 105005. doi: 10.1088/1674-4926/36/10/105005 ****
      G L Xiao, Y L Qin, W L Xu, B L Wei, J H Duan, X M Wei. Demonstration of a fully differential VGA chip with small THD for ECG acquisition system[J]. J. Semicond., 2015, 36(10): 105005. doi: 10.1088/1674-4926/36/10/105005.
      shu

      Demonstration of a fully differential VGA chip with small THD for ECG acquisition system

      DOI: 10.1088/1674-4926/36/10/105005
      • 1.

        School of Information and Communication, Guilin University of Electronic Technology, Guilin 541004, China

      • 2.

        Guangxi Experiment Center of Information Science, Guilin 541004, China

      Funds:

      Project supported by the National Natural Science Foundation of China (Nos.61264001, 61465004, 61161003, 61166004), the Guangxi Natural Science Foundation (Nos.2013GXNSFAA019333, 2013GXNSFAA019338), the Science and Technology Research Key Project of Guangxi Department of Education (No.2013ZD026), and the Innovation Project of GUET Graduate Education (No.GDYCSZ201457).

      More Information
      • Corresponding author: xwl@guet.edu.cn
      • Received Date: 2015-02-03
      • Accepted Date: 2015-05-15
      • Published Date: 2015-01-25

      Catalog

        Journal of Semiconductors © 2017 All Rights Reserved   京ICP备05085259号-2

        /

        DownLoad:  Full-Size Img  PowerPoint
        Return
        Return