A safe electrical connection between the human body and the recording circuit is required for the acquisition of physiological signals such as the electrocardiogram (ECG), electroneurogram (ENG), or electromyogram (EMG). The recording chip is conventionally connected to the human body through a blocking capacitor. The capacitor avoids any DC current flowing from the recording system into the patient¡¦s body in the case of chip failure. However, the large capacitor area in an integrated chip and its effect on the signal transform function make the use of a coupling capacitor undesirable.
In principle, a DC-coupled system can be used to overcome this limitation. The DC-coupled amplifier connects directly to the patient. However, a DC failure current caused, for example, by a gate-oxide short failure could harm the patient. To detect a dangerous condition, a safety monitoring system is proposed in this thesis. The safety monitoring system applies a test signal and physiological signals to the amplifier input. The disappearance of the test signal in the event of circuit failure is detected at the amplifier output. The recording system can then be switched into a safe state.
The analysis of the monitoring system, its design procedure and simulation results are presented in this thesis. Moreover, the first measured results are reported for a system realized as an integrated circuit in TSMC 0.35 £gm 2P4M CMOS process technology.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0825110-132900 |
| Date | 25 August 2010 |
| Creators | Chang, Chi-huai |
| Contributors | Ya-Hsin Hsueh, Robert Rieger, Chua-Chin Wang, Jih-Ching Chiu |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0825110-132900 |
| Rights | not_available, Copyright information available at source archive |
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