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：The Design of Implanted Stimulator Circuit
Abstract:
The implanted situmulator used electrical stimulus to stimulate such as motor nerves,auditory nerves,optic nerves and so on,to achieve the restoration of the normal operation of the human body. Cochlear implant is a typical use of this.It is used to provide the sensation of sound to those who are profoundly deaf by delivering electrical stimulus to auditory nerve directly. In this paper，a high-voltage and a normal voltage bandgap reference are achieved by using classical bandgap circuit.Test results show that the high voltage bandgap can output a stable 1.2V reference voltage, and the temperature coefficient is about 24ppm/℃; the normal voltage bandgap can output stable 0.9V reference voltage,the temperature coefficient is about 12ppm/℃. By analyzing the first-order and secondary opamp’s time domain response, the output buffer’s structrue is improved to save about 90% power. A digital control circuit is designed.It used finite state machine design method.Clock-gating and low frequency clock method is used to cut down 80% power Consumption. Base on the above two modular,A cochlear implant used chartered 0.35 μm EEPROM is designed.It is a mixed signal circuit,and the total area is 2.5×2.75mm2. It can be used for different speech encoding algorithm. Test result shows it can provide biphasic current pulse stimulation for a maximum of 16 output channels;the current intensity’s range is 0-2000μA;the largest stimulation rate is about 15Kpulse/s;the stimulus pulse duration is 4-130 μs.The circuit’s components and each component’s function are described in detail,and also the circuit’s layout and the test result are given.