Research And Design On The Key Technology Of Wireless Deep Brain Stimulator

With the development of medical technology, implantable medical devices are widely used in current clinical treatment. Among them, deep brain stimulation has the advantages of minimal incision, fewer complications and adjustability, which becomes one of most effective therapeutic methods of Parkinson’s disease, dystonia and other neurological disorders. A small, wireless, high security and low power consumption deep brain stimulation is not only to meet the needs of clinical research but also to promote the development of deep brain stimulation.Based on the development of deep brain stimulator, this thesis gives the design properties. After a deep analysis of the principle of circuit, this thesis present a monolithic integrated low-voltage deep brain stimulator with wireless power and data transmission. Data and power are transmitted to the stimulator by mutual inductance coupling. The in-vivo stimulator includes data receiving module, energy receiving module, digit control module, and biphasic stimulus current generating module. The digit control module is realized by hardware description language, and synthesized to the gate level circuit. Therefore, the in-vivo stimulator can realize monolithic integration without external microprocessor, while the power consumption is dramatically reduced. The biphasic stimulus current generating module can generate the bipolar current with equal amplitude, while the charge balance can be realized and the damage caused by the charge accumulation can be prevented. In order to reduce power consumption, a Controlled Vth cancellation rectifier is proposed to provide the voltage supply, and the stimulator has two supply voltages (1.8V and 3.3V).The monolithic stimulator was fabricated in a SMIC 0.18 μm 1-poly 6-metal mixed-signal CMOS process, occupying 0.7x0.33mm2. Measurements show that, the stimulator can stably generate a specified current at the electrode with 13.56 MHz AC input. The maximum amplitude of current is 0.8mA which is adjustable in 64 levels, the maximum pulse width is 15μs, and the maximum intervals between bipolar pulses are 30μs. The total power consumption is approximately 180μW.