A Telemetry System using Intra body Communication for Neural Prosthesis

체내 통신은 인체를 통신 매체로 하여 신호를 전송하는 무선 통신 방식이다. 체내 통신 방식은 체내와 송수신 시스템 그리고 외부 접지를 통한 하나의 전류 패스를 형성함으로써 이루어지는데, 인공 와우와 같은 신경 보철 장치의 경우 피하에 이식되어 있기 때문에 외부 접지를 사용하기 어렵다. 따라서 본 논문에서는 이와 같은 접지의 영향을 받지 않는 체내 통신을 제안하여 신경 보철 장치를 위한 시스템을 개발하였다. 개발된 시스템은 이식된 보철 장치의 체내에 위치한 전극으로의 신호 전송이 가능하도록 설계되었다. 효과적인 통신을 위하여 실험동물의 피부 위 실험 및 피하 실험을 통해 신호 전송 특성을 조사하였으며, 피부 위 실험의 경우 약 10MHz, 피하 실험의 경우 약 3MHz 이상의 주파수 대역에서 최대 전송 이득을 가지는 것을 확인하였다. 본 시스템은 데이터 전송률 480kbps를 갖는 pulse width modulation (PWM) 방식을 사용한 인공 와우용 내부 전류 자극기에 적용하여 그 성능을 입증하였다.; Intra-body communication' is a wireless communication technology that uses a body as a transmission medium for electrical signals. Generally, an 'earth ground' is used to create an electric field for operating the system; however this operating method could not apply to telemetry for implanted neural prosthetic devices. So this paper suggests a newly designed intra-body communication for neural prosthetic devices. A floating system which has a couple of electrodes with body was studied to remove an influence of the 'earth ground'. We found that 10MHz is the most suitable carrier frequency in skin experiments and over 3MHz in subcutaneous experiments. The system has been applied to a current stimulator circuit for cochlear implant that uses pulse width modulation (PWM) method at 480kbps rate successfully.본 논문은 한국 과학 재단(KOSEF)의 지원을 받는 생체 전자 시스템 연구센터(NBS-ERC)의 지원으로 수행되었습니다

二相性 전류자극을 이용한 인공치아 시스템의 공학적 설계와 생물학적 성능에 대한 연구

학위논문(박사)--서울대학교 대학원 :전기. 컴퓨터공학부,2008.2.Docto

높은 외부잡음 억제 특성을 가진 고 수율 Neural Probe의 개발

학위논문(석사)--서울대학교 대학원 :전기·컴퓨터공학부,2004.Maste

Design of implantable circuit for neural prosthetic devices

This paper describes a design and implementation of an implantable circuit for neural prosthetic devices. It is recommended that the circuit should provide charge-balanced biphasic current pulses and the function of monitoring impedance of the electrode for safe and effective current stimulation. In our design, the current pulses are provided from binary weighted 8 current sources through switch network. And to implement the recording function we designed the voltage-to-time converter which converts the voltage measured between two electrodes into pulse duration of the output signal. The signal is sent to out-of-body by load modulation through bidirectional coil communication. And we proposed the pulse counting circuit in order to improve the robustness of being immune to the skin depth between two coils. The designed circuit was fabricated in 0.8 ㎛ High Voltage CMOS process. The pulse counting circuit successfully decodes the received signal from the implanted coil in the skin depth of up to 13mm at the data transmission rate of 125kbps with bit error rate of better than 1X10-6. The current can range from 0 to 1.86mA in 7.3uA steps. The chip was capable of providing 8000 pulses/s and sampling electrode voltage from 0.5V to 4.5V.본 연구는 과학기술부/한국과학재단 우수연구센터육성사 업의 지원으로 수행되었음( R11-2000-075-01001-0

Graphic User Interface System for Automatic Control of Various Configuration Neural Electrode Arrays

This paper reports a user interface system developed for controlling stimulation parameters for various configuration electrode arrays for neural prosthetic applications such as retina implant and cochlear implant. The system includes both hardware and software and is designed with graphical capability for easy access from users. Using this system, an experimenter will be able to relocate the configuration of electrodes, select ones and assign a set of stimulation parameters to those electrodes, such as amplitude, duration, and frequency. An user can make a batch process out of the stimulation sequences so the measurement can be done efficiently.This study was supported by Korea Science and Engineering Foundation (KOSEF) through Nano Bioelectronics and Systems Research Center (NBS-ERC) in Seoul National University, and by a grant of the Korea Health 21 R&D Project (A050251), Ministry of Health & Welfare, Republic of Kore

An Implantable Multichannel Stimulating System IC for Deep Brain Stimulation

This paper proposes a newly designed deep brain stimulation(DBS) system which have selective multi-channels and enable to control electrical stimulating parameter widely for various experiments. To realize the proposed system, neural current stimulation chip, wireless data and power transmitter/receiver are developed, and additional charging circuit and memory block are composed to total set of system. The system receives inductive power to operate only receiver and data at 125 kb/s from a amplitude shift keyed (ASK) 2.5 MHz carrier to generate stimulus pulses. The current stimulation chip has 12-bits inputs to adjust stimulus pulse parameter, 3-bits inputs for channel enable and 1-bits to control chip operating. This chip which was fabricated using 0.35um CMOS process can generate biphasic stimulus pulse with wide range. The prototype implant system size without battery is 20mm x 30mm x 3mm.본 연구는 과학기술부/한국과학재단 우수연구센터 육성사 업의 지원으로 수행되었습니다(R11-2000-075-01001- 0). 제작된 chip은 IDEC MPW 프로그램과 (주) 삼성전자의 지원에 의해 제작되었습니다

A Neural Chip for Simultaneous, 32 channel Electrical Stimulation and Neural Signal Recording

Neuronal networks can build up very complicate form as the period of neuronal culture. In order to analysis these networks, electrical stimulation for firing action potential and neural signal recording of distributed adjacent neurons should be carried out, simultaneously. This paper presents a system IC which can simultaneously perform multichannel electrical stimulation and neural signal recording. The developed IC was composed of 16 independent current DACs which were synchronized by external control signals. Analog PWM data receiver for setting stimulation parameters and stimulating electrode number was used for microcontroller based automatic control. Recording systems were implemented with discrete parts of amp, filter, etc. Stimulation and recording were simultaneously performed through planar type microelectrode arrays (MEA) that was neuron culture plate. Using presented system, we can continuously monitor the evolving process of neuronal network within an incubation system.본 연구는 과학기술부/한국과학재단 우수연구센터 육성 사업(R11-2000-075-01001-0)과 반도체설계교육센터 (IDEC)의 지원에 의해 수행되었습니다

An Electronic System IC for Enhancing Bone Formation in Dental Implant

This paper presents an electronic device for enhancing osseointegration of surrounding tissues in dental implant. Early bone formation between implant surface and surrounding tissue is very important to shorten period of treatment as well as decrease failure rate of implant surgery. In order to accelerate bone formation, we designed a biphasic electrical current (BEC) stimulator IC, having parameters of 20uA/cm2, 120us-duration and 100 pulses per second. It was integrated with micro-batteries in temporary healing abutment and the system operated for 7 days with continuous BEC stimulation in animal tests. The results of animal tests show that the proposed electronic system expends the osseointegration of the implant surface by 1.69-fold more than that of the controls. Based on these results, we proposed new electronic system that could be applied to accelerate bone formation in dental implant. These technologies also can be used to the patient with osteoporosis.본 연구는 보건복지부 과제(A040028(0405-E000- 0301-0007)와 과학기술부/한국과학재단 우수연구센터 육성사업의 지원으로 수행되었습니다(R11-2000-075- 01001-0). 제작된 chip 은 IDEC MPW 프로그램과 (주) 삼성전자의 지원에 의해 제작되었습니다

Development of a Biphasic Electrical Current Stimulator for Enhancing Early Bone formation in Dental Implant

In dental implant, early bone formation of surrounding implant surface has long been key technology to increase success rate. In this study, in order to enhance bone formation, we stimulated biphasic electrical current with 20μ A/cm2 through temporary healing abutment to a surrounding bone tissues. Developed small sized biphasic electrical current stimulator was integrated in temporary healing abutment with power source and the device was applied for 7 days in early stage of osseointegration in animal experiments.본 연구는 보건복지부 과제 (A040028(0405-E000- 0301-0007)와 과학기술 부/한국과학재단 우수연구센터 육성사업의 지원으 로 수행되었습니다(R11-2000-075-01001-0). 제 작된 chip은 IDEC MPW 프로그램과 (주) 삼성전 자의 지원에 의해 제작되었습니다

An Analog-Digital-Hybrid Single-Chip RX Beamformer with Non-Uniform Sampling for 2D-cMUT Ultrasound Imaging to Achieve Wide Dynamic Range of Delay and Small Chip Area

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