Research And Design Of Implantable Passive Spinal Cord Stimulator

With the development of microelectronics industry,chip design toward the miniaturization,low power consumption,high stability of the goal is getting closer,integrated circuit in the field of medical applications are more and more widely,implantable passive spinal cord stimulator is one of the important aspects.The implantable passive spinal cord stimulator has been widely used in clinical pain management because of its non-battery-powered characteristic.In this paper,the output circuit of implantable passive spinal cord stimulator is researched and designed.This paper mainly studies the stimulated output circuit of the implanted passive spinal cord stimulator.The realization function is to realize the amplitude of the stimulating current pulse,the frequency can be adjusted and the four electrodes can be switched.This circuit has many advantages such as no battery,low power consumption,high security,high reliability and so on.First of all,the paper expounds the background and significance of the research topic,and then analyzes the development status and development trend of the implanted stimulator,and puts forward the research content and the organizational structure of the paper according to the development status and the market demand.Secondly,the classification of implantable spinal cord stimulation is introduced in detail.The whole structure of the stimulator is designed,which includes three parts: the handheld control module,the in vitro emission module and the in vivo stimulation module.In this paper,a passive bi-directional current stimulator is proposed according to the actual clinical use of the stimulator,and the design index is determined.Then the stimulator output module is briefly introduced.Third,the stimulator output stage peripheral analog circuit design simulation,the clock generator module: the use of ring oscillator structure to increase the accuracy of the adjustable frequency to ensure that the clock frequency of 2MHz,for the digital circuit to provide a precise benchmark clock,reference current generation circuit: With temperature compensation structure generates a reference current of 50 uA to provide a reference current for the stimulator output circuit.High voltage generation circuit: the use of charge pump for boost,the use of cross-coupled charge pump structure,the loss of voltage transmission,boost speed.Fourthly,the output circuit of the stimulator is designed and tested,and the specific realization of the stimulating current and the realization of the electrodes switching are introduced in detail.The level shifter circuit is used to solve the control problem of the high voltage switch tube.The experimental verification of the actual chip proves the property of the stimulator output circuit designed in this paper.Finally,according to the layout design rules and precautions combined with the characteristics of the circuit designed the overall layout in this paper.