Ultra Low Power Capacitive Sensor Interfaces (eBook)

Wouter Bracke, Robert Puers, Chris Van Hoof (Autoren)

eBook Download: PDF

2007 | 2007
X, 104 Seiten
Springer Netherland (Verlag)
978-1-4020-6232-2 (ISBN)

Infos

This book describes ultra low power capacitive sensor interfaces, and presents the realization of a very low power generic sensor interface chip that is adaptable to a broad range of capacitive sensors. The book opens by reviewing important design aspects for autonomous sensor systems, discusses different building blocks, and presents the modular architecture for the generic sensor interface chip. Finally, the generic sensor interface chip is shown in state-of-the-art applications.

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The increasing performance of smart microsystems merging sensors, signal processing and wireless communication promises to have a pervasive impact during the coming decade. These autonomous microsystems nd applications in sport evaluation, health care, environmental monitoring and automotive s- tems. They gather data from the physical world, convert them to electrical form, compensate for interfering variables or non-linearities, and either act - rectly on them or transfer it to other systems. Most often, these sensor systems are developed for a speci c application. This approach leads to a high rec- rent design cost. A generic front-end architecture, where only the sensors and the microcontroller software are customized to the selected application, would reduce the costs signi cantly. This work presents a new generic architecture for autonomous sensor nodes. The modular design methodology provides a exible way to build a complete sensor interface out of con gurable blocks. The settings of these blocks can be optimized according to the varying needs of the application. Furthermore, the system can easily be expanded with new building blocks. The modular system is illustrated in a Generic Sensor Interface Chip (GSIC) for capa- tive sensors. Many con guration settings adapt the interface to a broad range of applications. The GSIC is optimized for ultra low power consumption. It achieves an ON-state current consumption of 40?A.

Inhalt

Contents 6
Foreword 9
INTRODUCTION 11
GENERIC ARCHITECTURES FOR AUTONOMOUS SENSORS 14
1. Introduction 14
2. Multisensor microsystem 15
2.1 Sensors 15
2.2 Sensor interface chip 16
2.3 Microcontroller 17
2.4 Wireless link 18
2.5 Power management 18
3. Modular design methodology 19
3.1 Programming flow 20
3.2 Operational flow 22
4. Conclusion 23
GENERIC SENSOR INTERFACE CHIP 25
1. Introduction 25
2. Capacitive sensors 26
3. Generic Sensor Interface Chip for capacitive sensors 28
3.1 Front-end architecture 29
3.2 Capacitance-to-Voltage convertor 32
3.3 Chopping scheme 36
3.4 SC amplifier 37
3.5 S. modulator 41
3.6 Bandgap reference, bias system and buffered reference voltage 50
3.7 Main clock, clock generation circuits and LF clock 56
4. Configuration settings 59
5. Noise 61
5.1 Bennet model 61
5.2 Noise calculations 62
5.3 Effective number of bits 67
6. Experimental results 68
6.1 Pressure monitoring system 70
6.2 Inclination monitoring system 73
7. Performance comparison 77
8. Conclusion 78
ALGORITHM FOR OPTIMAL CONFIGURATION SETTINGS 81
1. Introduction 81
2. Programmability 81
2.1 Full-scale loss 82
2.2 Programmability of Cref 83
2.3 Programmability of Cf 84
2.4 Programmability of ASC 88
2.5 Noise 90
3. Optimal settings 91
4. Results 92
5. Conclusion 93
PHYSICAL ACTIVITY MONITORING SYSTEM 94
1. Introduction 94
2. Background and motivation 94
3. Implementation 95
4. Conclusion 97
CONCLUSION 98
1. Realized developments 98
2. Suggestions for future work 100
References 102
Index 109

Produkt-Details

• Erscheint lt. Verlag: 15.6.2007
• Reihe/Serie: Analog Circuits and Signal Processing
• Reihe/Serie: Analog Circuits and Signal Processing
• Zusatzinfo: X, 104 p.
• Verlagsort: Dordrecht
• Sprache: englisch
• Themenwelt: Naturwissenschaften ► Physik / Astronomie
• Themenwelt: Technik ► Elektrotechnik / Energietechnik
• Themenwelt: Technik ► Nachrichtentechnik
• Schlagworte: Analog • Capacitive sensors • Electronics • Generic sensor interface • Integrated circuit • Modulator • semiconductor • Sensor • Ultra low power
• ISBN-10: 1-4020-6232-X / 140206232X
• ISBN-13: 978-1-4020-6232-2 / 9781402062322