This book presents new systems and circuits for implantable biomedical applications, using a non-conventional way to transmit energy and data via ultrasound. The authors discuses the main constrains (e.g. implant size, battery recharge time, data rate, accuracy of the acoustic models) from the definition of the ultrasound system specification to the in-vitro validation.The system described meets the safety requirements for ultrasound exposure limits in diagnostic ultrasound applications, according to FDA regulations. Readers will see how the novel design of power management architecture will meet the constraints set by FDA regulations for maximum energy exposure in the human body. Coverage also includes the choice of the acoustic transducer, driven by optimum positioning and size of the implanted medical device. Throughout the book, links between physics, electronics and medical aspects are covered to give a complete view of the ultrasound system described.
Provides a complete, system-level perspective on the use of ultrasound as energy source for medical implants;
Discusses system design concerns regarding wireless power transmission and wireless data communication, particularly for a system in which both are performed on the same channel/frequency;
Describes an experimental study on implantable battery powered biomedical systems;
Presents a fully-integrated, implantable system and hermetically sealed packaging.
Author(s): Francesco Mazzilli, Catherine Dehollain
Series: Analog Circuits and Signal Processing
Publisher: Springer
Year: 2020
Language: English
Pages: 155
City: Cham
Preface
Acknowledgements
Contents
About the Authors
List of Acronyms
List of Figures
List of Tables
1 Introduction
1.1 Book Outline
References
2 Ultrasound in Medicine
2.1 Ultrasonic Techniques
2.1.1 Pulse-Echo Ultrasound
2.1.2 Emerging Applications
2.2 In-Vitro Platform to Study Ultrasound
2.2.1 System Description
2.2.2 Construction of the Platform
2.2.3 Wireless Energy Transfer
2.2.4 Wireless Communication
2.3 Summary
References
3 Regulations and System Specifications
3.1 Safety Limits
3.2 System Specifications
3.2.1 Frequency Selection
3.2.2 Rechargeable Battery
3.2.3 Electroacoustic Transducers
3.2.4 Choice of the CMOS Technology
3.3 Summary
References
4 System Architecture: Control Unit
4.1 Front-End Architecture
4.1.1 Master and Slave Architecture
4.2 Class-E Power Amplifier
4.2.1 Tuning Methodology
4.2.2 Measurements
4.3 Beamforming and Beam Steering Techniques
4.4 Receiver
4.5 Summary
References
5 System Architecture: Transponder
5.1 Equivalent Circuit of a Piezoelectric Transducer
5.1.1 Three-Port Network Model
5.1.2 Electrical Model
5.1.3 Measurement and Simulation Results
5.2 Energy Harvesting Circuit
5.3 Design Methodology and Comparison of Rectifiers
5.3.1 Design Methodology for Passive Rectifier
5.3.2 Comparison of Rectifiers
5.3.3 Summary
5.4 Design of an Active Rectifier
5.4.1 A Novel Synchronous Rectifier
5.4.2 Simulation Results
5.4.3 Experimental Results
5.4.4 Summary
5.5 Voltage Regulator
5.5.1 Design of a Two-Stage Low-Drop-Out Regulator
5.5.2 PSRR Analysis
5.5.3 Experimental Results
5.6 OOK/ASK Demodulator
5.6.1 Quasi-Identical Cascaded Gain Stages
5.6.2 DC-Offset Cancelation Technique
5.6.3 Variable Gain Amplifier Structure
5.6.4 Output Buffer
5.6.5 Measurement Results
5.6.6 Summary
5.7 Load Shift Keying
5.7.1 Impedance Modulation
5.7.2 Modulator Architecture
5.8 Summary
References
6 Wireless Power Transfer (WPT) and Communication
6.1 Sensor Node I
6.2 Sensor Node II
6.2.1 IC2
6.3 Ultrasound Power Transfer
6.3.1 Link Efficiency
6.4 Ultrasound Communication
6.4.1 Uplink
6.4.2 Downlink
6.5 Summary
References
7 Conclusion
7.1 Outlook
Appendix
Appendix
Index
