Leonardo Zoccal

Implementation of Schottky Barrier Diodes (SBD) in Standard CMOS Process for Biomedical Applications

© 2012 Crepaldi et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Implementation of Schottky Barrier Diodes (SBD) in Standard CMOS Process for Biomedical Applications

A Vt independent voltage reference based on composite transistors operating in weak inversion

This paper describes a voltage reference circuit based on composite transistors and operating in weak inversion mode. The voltage reference was fixed in 100mV and the supply voltage can be as low as 0.8V. The weak inversion allows small current too leading the total power in the nW range. Simulation results points to a deviation (3σ and process corner) less than ±1%. The reference is indicated to be used in biomedical applications specially those that use implanted devices. In these cases the temperature impact is minimized since the human body has an effective biological system to keep it constant at about 37°C.

Standard CMOS implementation of Schottky Barrier Diodes for biomedical RFID

This paper presents and discusses the implementation of a Schottky Barrier Diode (SBD) in standard CMOS technology as a way to optimize the overall performance of a passive RadioFrequency Identification (RFID) based biomedical implants. It is essential to limit the transmitted power in passive tags, mainly for biomedical applications in order to avoid damaging the human tissues due to local overheating. The implementation of the SBD was obtained by changing the mask flow without any modification to the CMOS fabrication process. The procedure maintains the transistors functionality and adds a new device to a standard CMOS technology. The fabricated SBD structures present a low turn on voltage of approximately 300 mV and low capacitance that are important parameters for passive RFID.

A High Efficiency 0.13μm CMOS Full Wave Active Rectifier with Comparators for Implanted Medical Devices

A R T I C L E I N F O A B S T R A C T Article history: Received: 30 April, 2017 Accepted: 29 June, 2017 Online: 11 July, 2017 This paper presents a full wave active rectifier for biomedical implanted devices using a new comparator in order to reduce the rectifier transistors reverse current. The rectifier was designed in 0.13μm CMOS process and it can deliver 1.2Vdc for a minimum signal of 1.3Vac. It achieves a power conversion efficiency of 92% at the 13.56MHz Scientific and Medical (ISM) band.

Self-tuning of impedance matching for wireless power transfer devices

A new design of self-tuning impedance matching for wireless power transfer is investigated. The system efficiency was numerically calculated by varying the distance between the system transmitter/receiver with self-tuning and without it. This work introduces an analytic and numerical design of a device for wireless power transfer with self-tuning by capacitance, based on MPPT (Maximum Power Point Tracking) algorithm. The results show an increase of efficiency at 35.55% in 2 meters distance between transmitter and receiver devices when compared with a device without self-tuning.

Integration of IPs into the M8051 microcontroller

This paper presents the implementation and integration the AES 128 data encryption IP and the I2C serial communication interface IP, into the IP of the M8051 microcontroller. We detail each block and validate them though testbench simulation. We performed functionality testing in FPGA to verify the correct functioning of the IPs and their integration.

A Low Noise Low Power OTA with Adjustable Gain PID Feedback Network for EEG SoC Arrays

Standard electroencephalogram (EEG) exams are subject to noises and interferences that may mask or corrupt signals and may cause a wrong medical evaluation. The noise from the environment is more relevant for discrete topologies, in which the components are placed far apart from other. That problem is more relevant on the neurological amplifiers, where the signals are in the range of tens of microvolts. Thus, the use of integrated circuits for the neurological signal amplification is essential to reduce that interference.

Rf CMOS Background

The Metal-Oxide-Semiconductor Field-Effect-Transistor (MOSFET) (or just MOS) is widely used and presents many advantages over the bipolar transistors (BJT) in many applications. It requires less silicon area and its fabrication process is relatively simpler. It is possible to implement most analog and digital circuits using almost exclusively MOS transistors. All these properties allow packing a large number of devices in a single integrated circuit. Additionally, and most important, its operation requires less power, making it extremely suitable to RFID circuits. This chapter aims to provide background on MOS transistors, from its physical operation to modeling, including RF modeling. The basic knowledge is essential to analyze and to design RFID circuits implemented using CMOS transistors. The chapter also presents noise analysis which is essential to low voltage signal, as it is the case of RFID circuits.