0　引言　随着电子技术的飞速发展 ,电子器件的集成度越来越高 ,功能越来越完善 .传统模拟仪器因大规模集成电路的出现而逐步数字化、智能化 ,从而使医疗仪器诊断精度、效率以惊人的速度提高 .要想使数字化仪器正常运行 ,就要求电源电压必须稳定 .因为电源电压如果波动太大 ,就 0 Introduction With the rapid development of electronic technology, the integration of electronic devices is getting higher and higher, the function is more and more perfect.Traditional analog instruments due to the emergence of large-scale integrated circuits gradually digital and intelligent, so that medical equipment diagnostic accuracy, Efficiency increases at an alarming rate. To make digital instruments work properly, the power supply voltage must be stable. Because the supply voltage fluctuates too much,