Details

Autor(en) / Beteiligte

• Lee, Shuenn-Yuh
• Cheng, Chih-Jen

Titel

Systematic Design and Modeling of a OTA-C Filter for Portable ECG Detection

Ist Teil von

• IEEE transactions on biomedical circuits and systems, 2009-02, Vol.3 (1), p.53-64

Ort / Verlag

United States: IEEE

Erscheinungsjahr

2009

Quelle

IEEE Electronic Library Online

Beschreibungen/Notizen

• This study presents a systematic design of the fully differential operational transconductance amplifier-C (OTA-C) filter for a heart activities detection apparatus. Since the linearity and noise of the filter is dependent on the building cell, a precise behavioral model for the real OTA circuit is created. To reduce the influence of coefficient sensitivity and maintain an undistorted biosignal, a fifth-order ladder-type lowpass Butterworth is employed. Based on this topology, a chip fabricated in a 0.18- mum CMOS process is simulated and measured to validate the system estimation. Since the battery life and the integration with the low-voltage digital processor are the most critical requirement for the portable diagnosis device, the OTA-based circuit is operated in the subthreshold region to save power under the supply voltage of 1V. Measurement results show that this low-voltage and low-power filter possesses the HD3 of -48.9 dB, dynamic range (DR) of 50 dB, and power consumption of 453 nW. Therefore, the OTA-C filter can be adopted to eliminate the out-of-band interference of the electrocardiogram (ECG) whose signal bandwidth is located within 250 Hz.