臺灣博碩士論文加值系統

隨著電子生醫系統望微型化發展，裝置中能夠容納電池的空間大幅減少。由於電池尺寸的演進並不及半導體，導致單一裝置所能承載的電容量減少，進而縮短裝置使用壽命。有鑑於此，轉化周遭各式物理能量，諸如光能、熱能以及振動能等，的能源採集(energy harvesting)技術近年來受到廣泛的關注及研究。對於許多植入式生醫裝置而言，能源採集的可更新以及不虞匱乏等特性不啻為解決更換電池問題的一大福音。

以此為主題，本文提出一高效率壓電材料(piezoelectric material)能源採集介面電路作為起頭。將一般用於直流化交流電壓之全橋式整流器搭配上電感以及開關，即可大幅增加自壓電材料擷取出之能源量，而其技術需搭配之感測及控制電路僅需消耗小於一微瓦之功率。

接著，本文提出一兩級低輸入直流升壓電路(boost converter)用以處理由溫差發電材料(thermoelectric material)所供給之低電壓能量。藉由使用低閾值此電晶體以及本文所提出之設計原則，此升壓器可在無輔助(如輔助電壓、輔助震動等)的情況下將0.11伏特之電壓升壓至超越1伏，足供一低功耗生醫系統使用。

最後，本文提出一以溫差發電供能之無線心電監測系統暨心律不整偵測電路，藉以呈現能源採集介面電路的應用及整合潛力。

本文中所提出之電路均使用台積電0.18微米製程實現。

Owing to the shrink of biomedical electronic devices, the space permitted for battery is getting smaller and smaller, which results in the shortening of the device lifetime. As a promising solution, energy harvesting technique that scavenges power from ambient sources such as light, heat or vibration has been widely researched in recent years. Being renewable and inexhaustible, energy harvesting seems to be the best cure for the powering disease of the implant biomedical devices.

To begin with, a high efficiency piezoelectric energy harvesting interface is reported. With a company of an inductor and switches, the full-bridge rectifier can achieve a higher power extracting efficiency. The control overhead is much less than one micro watt.

Following, we presented a two-stage low-input boost converter as a thermoelectric energy harvesting interface in Chapter 3. With low threshold voltage MOS transistors and the design guideline we proposed, the boost converter is able to boost a 0.11V voltage up to a level above 1V with extra assistance.

The last work in this thesis is a thermo-powered wireless ECG monitoring system with arrhythmia detection circuit, which is a highly integrated biomedical system that shows the integration potential of the energy harvesting interface.

All the works are fabricated in TSMC 0.18μm 1P6M process.

誌謝 i
中文摘要 ii
Abstract iv
Contents v
List of Figures viii
List of Tables xiv
Chapter 1 Introduction 1
1.1 Motivation 1
1.2 Thesis Organization 2
Chapter 2 Piezoelectric Energy Harvesting Interface Circuit 4
2.1 Introduction to the Piezoelectric Material 4
2.2 Commonly used Interfaced Circuits 6
2.2.1 Half-wave Rectifier 8
2.2.2 Voltage-multiplying Rectifier 10
2.2.3 Full-bridge Rectifier 13
2.3 Bias-flip Interface Circuit Scheme 17
2.3.1 Introduction to Bias-flip Rectifier 17
2.3.2 Comparison between Full-bridge Rectifier and Bias-flip Rectifier 22
2.4 Architecture of the Bias-flip Rectifier 23
2.5 Circuit Implement of the Bias-flip Rectifier 24
2.5.1 Zero-current Sensing and Control Circuit 25
2.5.2 Low Power Reference Circuit 31
2.5.3 Layout Consideration 33
2.6 Simulation Results 36
2.7 Measurement Results 39
2.8 Summary 45
Chapter 3 Thermoelectric Energy Harvesting Interface Circuit 47
3.1 Introduction to the Thermoelectric Material 47
3.2 Basics of DC-DC Boost Converter 49
3.2.1 Inductor Volt-second Balance Principle 50
3.2.2 Fundamental of Operation 51
3.2.2.1 CCM 52
3.2.2.2 DCM 56
3.2.3 Closed-loop Control Scheme 58
3.2.3.1 Pules-Width Modulation (PWM) 58
3.2.3.2 Pules-Frequency Modulation (PFM) 59
3.3 Architecture of the Proposed Two-stage Low-input DC-DC Boost Converter 60
3.4 Circuit Implement of the Proposed Two-stage Low-input DC-DC Boost Converter 64
3.4.1 Converter Core Design Methodology 64
3.4.2 Timing Circuit 69
3.4.3 Gate-driving Auxiliary Circuit 72
3.4.4 Burst Mode Control Scheme 73
3.5 Simulation Results 75
3.6 Measurement Results 80
3.7 Summary 84
Chapter 4 A Thermo-powered Wireless ECG Signal Monitoring System with Arrhythmia Detection Circuit 86
4.1 Introduction to ECG signal 86
4.2 Architecture of the proposed ECG System 91
4.3 Circuit Implement of the proposed ECG System 92
4.3.1 Analog Front-end (AFE) 92
4.3.2 Analog-to-digital Converter (ADC) 93
4.3.3 Digital Signal Processing Circuit (DSP) 94
4.3.4 OOK/FSK Transmitter (TX) 96
4.3.5 OOK Receiver (RX) 99
4.3.6 DC-DC Boost Converter 100
4.3.7 Low-dropout Regulator (LDO) 100
4.4 Simulation and Measurement Results 102
4.5 Summary 107
Chapter 5 Conclusion 110
Appendix 112
Reference 114

[1]Chao Lu, Vijay Raghunathan, and Kaushik Roy, “Efficient Design of Micro-Scale Harvesting Systems,” IEEE J. on Emerging and Selected Topics in Circuit and Systems, vol. 1, no. 3, Sep. 2011
[2]Sujesha Sudevalayam and Purushottam Kulkarni, “Energy Harvesting Sensor Nodes: Survey and Implications,” IEEE Communication Surveys & Tutorials, vol. 13, no. 3, third quarter 2011
[3]Yogesh Kumar Ramadass, “Energy Processing Circuits for Low-Power Applications,” Massachusetts Institute of Technology PhD thesis, Jun. 2009
[4]S. Roundy, P. Wright, and J. Rabaey, “Energy Scavenging for Wireless Sensor Networks with Special Focus on Vibrations,” Kluwer Academic Press, 2003.
[5]T. Le, J. Han, A. von Jouanne, K. Mayaram, and T. Fiez, “Piezoelectric Micro- Power Generation Interface Circuits,” IEEE Journal of Solid-State Circuits, vol. 41, no. 6, pp.1411–1420, June 2006.
[6]Giuseppe De Vita and Giuseppe Iannaccone, “A Sub-1-V, 10 ppm/ C, Nanopower Voltage Reference Generator,” IEEE J. on Solid-State Circuits, vol. 42, no. 7, Jul. 2007
[7]Yogesh K. Ramadass and Anantha P. Chandrakasan, “An Efficient Piezoelectric Energy Harvesting Interface Circuit Using a Bias-Flip Rectifier and Shared Inductor,” IEEE J. on Solid-State Circuits, vol. 45, no. 1, Jan. 2009
[8]J. Lim, C.-K. Huang, M. Ryan, G. J. Snyder, J. Herman, and J.-P. Fleurial,” MEMS/ECD Method for Making Bi2−xSbxTe3 Thermoelectric Devices,” NASA Tech Briefs, vol. 32, no. 7, pp. NPO–30 797, Jul. 2008.
[9]W. M. and S. M., Design and Implementation of Fully-Integrated Inductive DC-DC Converters in Standard CMOS. Springer, 2011
[10]Robert W. Erickson and Dragan Maksimovic, Fundamental of Power Electronics. Springer, 2001
[11]Anna Richelli, Simone Comensoli, and Zsolt M. Kovacs-Vajna, ”A DC/DC Boosting Technique and Power Management for Ultralow-Voltage Energy Harvesting Applications,” IEEE Transactions on Industrial Electronics, vol. 59, no. 6, Jun. 2012
[12]David M. Dwelley, " Voltage mode feedback burst mode circuit," U. S. Patent 6307356 B1, Jun. 18, 1998
[13]Fairchild Semiconductor, Appl. Note 118, Oct. 1974
[14]Hans Raben, Johan Borg and Jonny Johansson, “An Active MOS Diode with Vth-Cancellation for RFID Rectifiers,” IEEE International on RFID, 2012
[15]Po-Hung Chen, Koichi Ishida, Katsuyuki Ikeuchi, Xin Zhang, Kentaro Honda, Yasuyuki Okuma, Yoshikatsu Ryu, Makoto Takamiya, Takayasu Sakurai, “A 95mV-Startup Step-Up Converter with VTH-Tuned Oscillator by Fixed-Charge Programming and Capacitor Pass-On Scheme,” IEEE International Solid-State Circuit Conference, vol. 12, no. 1, Feb. 2011
[16]“Lesson 1: The Standard 12 Lead ECG”. Library.med.utah.edu.
[17]“Intro to Piezoelectric Transducer Crystals”. http://bostonpiezooptics.com/intro -to-transducer-crystals.
[18]“Limb Leads – ECG Lead Placement – Normal Function of the Heart –Cardiology Teaching Package – Practice Learning – Division of Nursing – The University of Nottingham”. Nottingham.ac.uk.
[19]Behzad Razavi, Design of Analog CMOS Integrated Circuits. McGraw-Hill, 2001