• Journal of Korea Society of Digital Industry and Information Management
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• v.19 no.2
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• pp.11-25
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• 2023

With the increasing advancement of VLSI technology, health care system is also developing to serve the humanity with better care. Therefore, biomedical implantable devices are one of the amazing important invention of scientist to collect data from the body cell for the diagnosis of diseases without any pain. This Biomedical implantable transceiver circuit has several important issues. Oscillator is one of them. For the design flexibility and complete transistor-based architecture ring oscillator is favorite to the oscillator circuit designer. This paper represents the design and analysis of the a 9-stage CMOS ring oscillator using cadence virtuoso tool in 180nm technology. It is also designed to generate the carrier signal of 403.5MHz frequency. Ring oscillator comprises of odd number of stages with a feedback circuit forming a closed loop. This circuit was designed with 9-stages of delay inverter and simulated for various parameters such as delay, phase noise or jitter and power consumption. The average power consumption for this oscillator is 9.32㎼ and average phase noise is only -86 dBc/Hz with the source voltage of 0.8827V.

• Journal of Biomedical Engineering Research
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• v.26 no.5
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• pp.309-317
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• 2005

It is expected that fully-implantable middle-ear hearing devices (FIMEHDs) will soon be available with the advantages of complete concealment, easy surgical implantation, and low power operation to resolve the problems of semi-implantable middle-ear hearing devices (SIMEHDs) such as discomfort of wearing an external device and replacement of battery. Over the last 3 years, a Korean research team at Kyungpook National University has developed an FIMEHD called ACRHS-1 based on a differential floating mass transducer (DFMT). The main research focus was functional improvement, the establishment of easy surgical procedures for implantation, miniaturization, and a low-power operation. Accordingly, this paper reviews the overall system architecture, functions, and experimental results for ACRHS-1 and its related accessories, including a wireless battery charger and remote controller.

• Journal of Biomedical Engineering Research
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• v.31 no.5
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• pp.395-400
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• 2010

Hypertension is the chronic disease that the 16% of total population are suffering, and it needs to be studied to find alternative treatment because of the tolerance and side effect of medications that may bother some patients. in this paper, we verified practicality of implantable electrical stimulator that can readily change stimulus magnitude and frequency. And this device is possible to stimulate baroreflex or parasympathetic nerve. Therefore we performed in vitro tests and animal experiment for device's operating conditions. This device consist of implantable electrical stimulator and extracorporeal control/monitoring system. Stimulator was designed to make 1Hz~100Hz pulses and it can change continuous or periodic pulse train type. And this device can control stimulator's function and monitor stimulator's status and patients' blood pressure at exterior of body using ZigBee module as wireless telecommunication. We verified that stimulator have error rate under 5% at 50mm depth of organs and, stimulator makes high-efficiency energy with closer position of two electrodes. Also we can confirm the performance of device that decreasing blood pressure and heart rate of a rat by electrical stimulation.

• Journal of Sensor Science and Technology
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• v.21 no.2
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• pp.144-150
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• 2012

A microphone for fully implantable hearing device was generally implanted under the skin of the temporal bone. So, the implanted microphone's characteristics can be affected by the accompanying noise due to masticatory movement. In this paper, the implantable microphone with 2-channels structure was designed for reduction of the generated noise signal by masticatory movement. And an experimental model for generation of the noise by masticatory movement was developed with considering the characteristics of human temporal bone and skin. Using the model, the speech signal by a speaker and the artificial noise by a vibrator were supplied simultaneously into the experimental model, the electrical signals were measured at the proposed microphone. The collected signals were processed using a general adaptive filter with least mean square(LMS) algorithm. To confirm performance of the proposed methods, the correlation coefficient and the signal to noise ratio(SNR) before and after the signal processing were calculated. Finally, the results were compared each other.

• Journal of Sensor Science and Technology
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• v.19 no.5
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• pp.361-368
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• 2010

ACROSS device, which is composed of an implantable microphone, a signal processor, and a vibrating transducer, is a fullyimplantable middle ear hearing device(F-IMEHD) for the recovery of patients with hearing loss. And since a microphone is implanted under skin and tissue at the temporal bones, the amplitude of the sound wave is attenuated by absorption and scattering. And the vibrating transducer attached to the ossicular chain caused also the different displacement from characteristic of the stapes. For the gain control of auditory signals, most of implantable hearing devices with the digital audio signal processor still apply to fitting rules of conventional hearing aid without regard to the effect of the implanted microphone and the vibrating transducer. So it should be taken into account the effect of the implantable microphone and the vibrating transducer to use the conventional audio fitting rule. The aim of this study was to measure gain characteristics caused by the implanted microphone and the vibrating transducer attached to the ossicle chains for the gain compensation of ACROSS device. Differential floating mass transducers (DFMT) of ACROSS device were clipped on four cadaver temporal bones. And after placing the DFMT on them, displacements of the ossicle chain with the DFMT operated by 1 $mA_{peak}$ current was measured using laser Doppler vibrometer. And the sensitivity of microphones under the sampled pig skin and the skin of 3 rat back were measured by stimulus of pure tones in frequency from 0.1 to 8.9 kHz. And we confirmed that the microphone implanted under skin showed poorer frequency response in the acoustic high-frequency band than it in the low- to mid- frequency band, and the resonant frequency of the stapes vibration was changed by attaching the DFMT on the incus, the displacement of the DFMT driven with 1 $mA_{rms}$ was higher by the amount of about 20 dB than that of cadaver's stapes driven by the sound presssure of 94 dB SPL in resonance frequency range.

• Journal of Biomedical Engineering Research
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• v.17 no.4
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• pp.535-544
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• 1996

In this paper, we analyzed the coil-magnet type vibrating transducer for the implantable middle ear hearing aid which is appropriate for patient's hearing level, and an experimental transducer system is designed For the objective and quantitative analysis of the transducer, a theoretical equivalent model containing coil, magneto and inner ear is developed To perform effective evaluation of the transducer, a transforming ratio Tr is introduced and its range that is suitable for practical implantable middle ear hearing device is foun4 The result of applying physical parameters of ear system to the proposed analytical model shows that frequency response of the coil magrlet type vibrator is predominantly governed by resistive impedance of the coil rather than inertia effect of the magnet and the inner parameters. In addition, we realized an experimental middle ear hearing aid system to show the theoretical validity of designed system and this will provide the basis of the development for actually implantable system.

• Journal of Sensor Science and Technology
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• v.18 no.1
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• pp.63-71
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• 2009

It is said that the desirable bio-signal measurement and stimulation system should be an implantable type if the several problems such as biocompatibility, electrical safety, and so on are overcome. In addition to the biocompatibility issue, a robust RF communication and a stable electrical power source for the implantable bio-signal measurement and stimulation system are very important matters. In this paper, a wireless telemetry system which adopts the FCC's approved MICS (medical implant communication service) protocol and a wireless power transmission has been proposed. The proposed system composed of a base station (BS) and an implantable medical device (IMD) has the advantages that the interference with other RF devices can be reduced by the use of the specially assigned MICS frequency band of 402.MHz to 405 MHz. Also, the proposed system includes various functions of a multi-channel bio-signal acquisition and an electric stimulation. Since the electrical power for the IMD can be provided by the inductive link between PCB patterned coils, the IMD needs no battery so that the IMD can be smaller size and much less dangerous than the active type IMD which includes the internal battery. Finally, the validity as a wireless telemetry system has been demonstrated through the experiments by using the implemented BS and IMD.

• Journal of Biomedical Engineering Research
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• v.19 no.5
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• pp.487-495
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• 1998

In this paper, a new type of implantable middle ear hearing aid, which consists of external loop coil, a small magnet and a simple external device, is proposed. The internal device of proposed type consists of only a small magnet and the external device does not need to be positioned behind the ear or in the ear canal. The proposed type is excellent in cosmetic sides and very convenient to use, because the external device can be hidden in upper garment and collar of clothes. Also, purposely this type doesn't need to be small on the size of battery, which means it has longer battery life. Therefore, the battery is not necessary to be charged frequently. It also can solve the difficulty of gap calibration at surgical operation which conventional Implantable middle. Therefore, the battery is not necessary to be charged frequently. It also can solve the difficulty of gap calibration at surgical operation which conventional implantable middle ear hearing aid has. We investigate the performance of proposed implantable middle ear bearing aid and we analyze that proposed type is appropriate for mild and severe hearing impaired person and the result of experiment showed the accuracy of our analysis. For the validation of our analysis we used the temporal bone at the experiment and confirm that ossicles can be vibrated when the proposed system In startled in the body.

• Journal of Korea Multimedia Society
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• v.18 no.5
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• pp.652-662
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• 2015

It is necessary to develop small, implantable bio-telemetry systems which can measure and transmit patients' bio-signals from internal body to external receiver. When measuring bio-signals, like electrical bio-signals, acoustic bio-signal measurement has also a big clinical usefulness. But, sound signal has larger frequency bandwidth than any other bio-signals. When considering these issues, a wireless telemetry system which has rapid data transmission rate proportional to wide frequency bandwidth is necessary to be developed. The bluetooth module is used to overcome the data rate limitation caused by the large frequency bandwidth. In this paper, a novel multimedia bluetooth biotelemetry system was developed which consists of transmitter module located in the body and receiver device located outside of the body. The transmitter consists of microphone, bluetooth, and wireless charging device. And the receiver consists of bluetooth and codec system. The sound inside the skin is captured by microphone and sent to receiver by bluetooth while charging. The wireless charging system constantly supplies the electric power to the system. To verify the performance of the developed system, an in vitro experiment has been performed. The results show that the proposed biotelemetry system has ability to acquire the sound signals under the skin.

• Journal of Biomedical Engineering Research
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• v.29 no.6
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• pp.415-430
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• 2008

The technologies in medical electronic implant(MEI) devices are developing rapidly, and already, there are various kinds of the MEI devices in the current medical equipments market. Recently, the global market scale of MEI devices have been increased about 13% year by year, and the import amount of MEI devices in Korea is increasing rapidly. In the near future, the demands of MEI devices will be magnificently increasing by the continuous development of the biomedical electronics devices which coupled with neural, brain and other organs will bring us to tremendous effects, such as providing new therapeutic solutions to patients, extension and saving human life, and an important clue of medical development. However, the investment of the research and the activity of developments in this field are still very weak in the Korea. Consequently, this paper introduces about the research trends of MEI devices, and technological problems those must be solved, and then concludes with the suggestions in order to be the leading country in this field.