一個安全連接在積體電路跟人體之間是被人體訊號記錄系統所需要的，像ECG、ENG、EMG，典型的紀錄系統是透過一個大電容連結到人體上，大電容可以避免系統出問題的時候直流電流直接流進人人體對人體產生傷害，可是在現在電路積體化的時代，大電容因為面積大，且會造成轉移函數的改變，因此這種連接方式造成了記錄生理訊號系統的不便，而使用直流交耦直接連結人體跟放大器就可以打破這種限制，但是系統直接連結人體則可能因為系統故障造成直流電流直接流入人體中，進而傷害人體，例如閘極氧化層短路效應(gate oxide short)等，本論文中所提及的安全監控系統則是爲了監控此種現象，避免人體受到傷害。
其原理就是在生理訊號中加入了一個高頻的測試訊號，疊加後的訊號通過放大器放大，當一個非預期的電流流入人體中，則測試訊號會消失在放大器輸出級，安全監控裝置就會把狀態轉移到安全模式，防止電流經由晶片繼續流入到人體中。
電路公式、設計過程還有電路模擬甚至測量結果在論文中都有詳細的描述，論文中所提到的安全監控系統是使用TSMC 0.35 um 2P4M CMOS製程設計的。

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 μm 2P4M CMOS process technology.

摘要 I
Abstract II
致謝 III
Chapter 1 Introduction 1
1.1 General Background Information 1
1.2 The Gate Oxide Short Defect (GOS) 2
1.3 Contribution of this Thesis 3
Chapter 2 Safety monitoring system for bio-chips 5
2.1 Proposed monitoring system 5
2.2 Test signal application 6
2.2.1 The differential test signal oscillator with amplitude control 10
2.2.2 The main amplifier 20
2.3 Test signal detection 24
2.3.1 The high pass filter 24
2.3.2 The low pass filter 27
2.3.3 The alarm system 31
Chapter 3 Simulation result 35
3.1 The differential oscillator with amplitude control 35
3.2 Test signal application circuit 37
3.3 The main amplifier 39
3.4 The high pass filter 41
3.5 The low pass filter 43
3.6 The alarm system 45
3.7 The proposed system 46
Chapter 4 Measured results 48
4.1 The differential oscillator with amplitude control 49
4.2 The main amplifier 50
4.3 The high pass filter 52
4.4 The low pass filter 53
4.5 The alarm system 54
4.6 The proposed system 55
4.7 Die photo of the safety system 59
Chapter 5 Conclusion and future works 60
5.1 Conclusion 60
5.2 Future work 61
References 62

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