Hearing Aid Device
The National Institute on Deafness and Other Communication Disorders - part of the National Institutes of Health - reports that one in eight people in the United States aged 12 years or older has hearing loss in both ears, based on standard hearing examinations. Despite this, the World Health Organization states that current production of hearing aids meets less than 10 percent of global need and that about 5 percent of the world's population - 360 million people - have disabling hearing loss. Thus, it has been important to develop acoustic medical devices regardless of countries. The purpose of this research is to develop a low power hearing aid integrated circuit (IC) containing a pre-amplifier, an analog-to-digital converter (ADC), a modulator, and an audio amplifier.
Analog IC design utilizing Memristors
The Memristor was devised by Leon Chua in 1971. In 2008, R.S Williams at HP fabricated the first device which behaves as the memristor under certain conditions. The model had TiO2 and TiO2-x regions bounded by metal plates. After an external voltage is applied, the oxygen vacancies move and remain immobile when supply is turned off. It remembers the past applied inputs and resistance values. Hence the name memristor (memory-resistor). Due to its small size, low parasitics and non-volatility, it is used for highly integrated, non-volatile memories.
Memristors can also be used in analog applications such as fine programmable resistors and in sense-amplifier design. It also has applications in neuromorphic computing and as synapse in brain.
Our research is focussed on analog applications of memristors in collaboration with Dr. David Hoe from Loyola University, Maryland.
Environmental Sensing Systems and Circuits
To measure the water quality in the nature source, a submerged array of sensors are created to provide real-time, large area identification. The sensors monitor for months with a battery, communicating with the base station via wireless transceiver, eliminating the need to retrieve the sensor frequently and saving a lot of money and human resource.
The purpose of readout circuit is to amplifier the current signal from PIN photo-detector, then get the information of chemical species on the sensor. Thus, a sensor readout circuit including trans-impedance amplifier(TIA) and ADC are required to design. To obtain a precise result, we aim to develop the readout circuit with low noise and low power consumption.
As sensor technology has been developed, electrochemical sensors lead a trend of smart sensing systems, which allows Point-of-Care-Testing. This evolution in the health care area has set a task for researchers to develop new architectures with low power consumption and compactness for the measurement system, as well as achieving accuracy, sensitivity, range and stability. In order to achieve these requirements, AMIC Lab has developed electrochemical sensor readout circuit systems for chemical detection and bio application such as glucose monitoring and gas sensing.
Wireless Power Transfer System
Wireless power transfer technology has received much attention for the portable electronic device and medical implant charging. Wireless power transfer systems are necessary to provide fast charging time, high efficiency, long range, and human safety for ultimate ubiquitous charging. To implement it, an inductive coupling, a magnetic resonance, a radio frequency harvesting, and an optical power transfer have been researched. We are interested of developing an optical power transfer system for rapid charging. In addition, highly efficient rectifier and DC-DC converter for the magnetic resonance method is under researching.