Research And Design Of Key Modules In High Compliance Voltage Wireless Functional Electrical Stimulation System

Implantable Medical Devices(IMDs)has been proven as a effective therapy to alleviate nerve disease.So,it is very important to improve the energy efficiency and performance of IMDs.Compared to the subcutaneous cable power supply of implantable battery,wireless energy transmission across the skin is currently the only viable solution to overcome size,power limitation of battery while improving the performance of IMDs.On the other hand,the energy delivery structure which used in IMDs should have higher power conversion efficiency(PCE),meanwhile,it could operate at less received power and further distance.Therefore,it is of great significance to design a functional electric stimulator with wireless energy transmission,universal configurable,high efficiency and low power consumption.In this thesis,some key modules that can be used in high compliance voltage wireless functional electrical stimulator system are proposed after researching and analyzing the present situation of functional electric stimulator.This thesis proposed a new structure of current-based wireless power transmission(CWPT),which can improve the efficiency of the transcutaneous wireless power transmission and the output voltage performance of the receiver(Rx)effectively.Unlike conventional inductive energy delivery that uses a LC-tank of the receiver(Rx)as a voltage source,the proposed current-based wireless energy transfer architecture treats the LC-tank as a current source in a novel way.This eliminates the demand for DC-DC charge pumps or AC-DC voltage multipliers,both of which require several capacitors and diodes.The CWPT itself can achieve the function of AC-DC conversion with a higher voltage conversion efficiency.The module named wireless data transmission is responsible for recovering the received modulation signal;The function of clock recovery module is restore clock signals which the system needs;And the stimulation-controlled module combines the data and clock signals to produce low voltage control signals which can control the high output voltage of CWPT through level translator.The circuit designed in this thesis adopts TSMC 0.18 μm high voltage BCD process,and using software such as Cadence-Spectre for designing and simulating.The simulation result show that,the CWPT can provide DC voltage ranging from-10 V to10V and achieve various intensities galvanism at an operation frequency of 1 MHz;And in the 13.56 MHz AC input case,wireless data recovery module can receive and demodulate 28 bit data signals which provide for other module in the system;Othermodule such as clock recovery module and stimulus control module can also provide correct and effective clock signals and control signals.