Biography
Enrollment Date: 2006
Graduation Date：2009
Degree：M.S.
Defense Date：2009.06.02
Advisors：Chun Zhang
Department：Institute of Microelectronics，Tsinghua University
Title of Dissertation/Thesis：Research On Multi-electrodeElectrical Stimulator and Design of Data Transmission Circuit
Abstract:
Multi-electrode electrical neural stimulator is widely used in medicine such as cochlear implant, retinal prosthesis, Deep Brain Stimulation and so on, which have been realized clinically. Cochlear implant is one of the most successful implanted devices. As a effective method of restoring the hearing of the patients with profound hearing loss, research on multi-electrode cochlear implant and the related ASIC is of virtual social importance and it will contribute greatly to rehabilitation of 2.5 million patients with profound hearing loss in our country. What’s more, the cochlear devices used in present clinical operation are most developed by foreign coutries so the cost of equipment and testing is pretty high. It is necessary and important that we develop the cochlear implant chips that can work stablely and achieve optimal improvement on the area and power dissipation by ourselves. At the same time, in view of the safety of surgery and in order to lessen the patients’ pain, multi-electrode cochlears implant mainly transfer the information and energy through transformer coupling. Transformers coupling in different implanted electrical neural stimulators with application background exist great similarities not only in circuit constructions but also in parameters. So the research on wireless data/power transmission system is useful and important. The paper takes cochlear implant as an example to introduce actual applications: application status, developmental trend of multi-electrode electrical neural stimulator. Then the hardware moudles, the function of each moudle, parameters. Interface connections are described detailedly. Then, there are introductions of the design and test of information unit and energy-recovery unit. The internal current realized the following functions: represented clock&data signals from those received by loops and sent them to logic control units of cochlear implant, in the same time represented a DC current to power the high voltage unit. The next chapter is about hardwares of external current and the software setting of them. The external wireless signal sending current bases on a independent element - Atmega32 and EME4094. The needed signals are configured through internal internal register which controlled by software mentioned above. The following are introductions of functions, test methods, test results and conclusions of digital circuit, switch matrix circuit,DAC circuit in the order of test. The test verifies that the chip could work properly and gives the testing parameters. The paper gives the analysis of the reason and the possible solution of the problem of spike noise. The demo system that can produce stimulus current as long as the program is downloaded into MCU is built based on above test. Grounded on all above work, the wireless test on multi-electrode cochlear implant is realized and then the paper analyses the test results which is the important reference and information for farther improvements.