The Design Of Pulse Electrotherapy Equipment Based On ARM System

With the development of science technology, and the enhancement of awarenessof human health, medical electrotherapy equipments are used more and morewidely.The electrotherapy can produce certain biological pulse to stimulate thehuman body.It can improve blood circulation,nutrient metabolism,and improveimmune function. Currently,foreign and domestic electrotherapy equipmentscommonly use square wave,sharp wave,sine wave,triangular wave,sawtooth wave,etc.These waveforms make people have the problem of habitual adaptation,and theoutput power of the electrotherapy equipments can not be too large to reachtherapeutic effect.For the shortcomings,this paper designed a pulse electrotherapyequipment based on ARM system.This electrotherapy equipment includes ARMsystem,keys,LCD,DAC,boost power supply,waveform amplifier,switching circuitsand treatment electrode.As the control core,the ARM system is used to producetherapeutic waveforms,display the type and level of the waveforms with theLCD,scan the keys,control the output of DAC,amplify the waveforms and control theswitching circuits.The electrotherapy equipment this paper designed can produce11kinds of waveforms.The highest amplitude of the waveforms can reach120V,and thefrequencies are from500Hz to40kHz.When the clients set the type and level of thetreatment waveforms,the ARM system willl receive the information and call theappropriate treatment waveform that the client set.At last the switching circuits outputthe waveforms by the treatment electrode to human body. We summarized thedifferent feelings that different waveforms to human body.According to theexperiments,the electrotherapy equipment that we designed is safe and reliable.Theelectrotherapy equipment this paper designed is simple to use,safe,practical and thewaveforms are diverse.1.According to the requirements of the project, our main contents are as follows: (1)This paper designed a pulse electrotherapy equipment based on ARM systemto solve the problem of existing electrotherapy equipments that they were not safeenough or easy to control.This paper analyzes the theory of electrotherapy equipmentsfirstly,then provides the overall design and choose the best method to design theamplifier.(2)This paper designed the hardware circuit of pulse electrotherapy equipmentbased on ARM system. This electrotherapy equipment includes ARMsystem,keys,LCD,DAC,boost power supply,waveform amplifier,switching circuitsand treatment electrode.We analyzed the working principle and working process ofevery module circuit.(3)This paper designed the software of pulse electrotherapy equipment based onARM system.We designed the software for Mini2440development board and debugthe program with ADS that the ARM system provided.The programs includes themain program,the program of LCD and keys,and the waveforms generator.(4)This paper processed the instrument experimental datas and analyzed theresults.We used MATLAB to analyze and compare the spectrums and so on of thewaveforms,and we summarized the different feelings that different waveforms tohuman body.According to the experiments,the electrotherapy equipment that wedesigned is safe and reliable.2.Based on the above contents,the key technologies of the design are:(1)boost power supply.We designed the boost power supply for the high-voltagetransistor.And we must thought of the security and portability.So this paper designedforward DC-DC12V to150V(15W).(2)high-voltage amplifier.In this paper,the design of high-voltage amplifier needsto amplify the voltage to about120V.We compared three methods which wereintegrated operational amplifier, pulse transformer amplifier,and HV transistoramplifier.After comprehensive comparision,we choosed the last method because ofhigh security,small signal distortion,high bandwidth and stable operation.(3)multi-level security measures.The security circuits are constituted by manypars of fuse and the output protection resistors.In boost power supply we use DC-DC to produce a high voltage with small power which is safer than rectified grid voltagedirectly.Besides,the time of excessive voltage and overcurrent protection is less than1ms which is far less than the fuse burn-out.