一种高压运算放大器的设计

【作者】 李学会；

【导师】 张波； 崔自中；

【作者基本信息】 电子科技大学 ， 软件工程， 2009， 硕士

【摘要】 1959年,世界上第一块集成电路在美国诞生。在此后的50年里,集成电路的设计技术获得了突飞猛进的发展。运算放大器作为模拟电路单元的核心模块,它的重要性日益受到人们的重视。人们在低电压运算放大器设计领域取得了巨大的成就,但在高压运算放大器设计领域,由于高压工艺的限制以及功率器件散热问题的影响,使得高压运放的发展远不如低压器件。近年来,由于在一些高压应用领域,如马达控制系统、压电传感器以及打印机驱动等电路中对高压运算放大器的迫切需求,使得对高性能高压运算放大器的设计成为一项最紧迫的任务。本文正是针对上述问题,通过深入研究运算放大器的工作原理以及高压功率器件耐压原理及高压BCD工艺和高压SOI工艺,运用德国Xfab工艺设计了一种运用于压电传感器以及电脑和真空界面的双高压运算放大器。该运放的供电电压为±175V,输出电流为60mA,直流电压增益为106dB,转换速率为40V/uS,功耗为200mW。MOSFET输出使运放避免了二次击穿限制,其功耗维持在最小值,每个放大器静态额定电流只有2mA.根据电路要求选择了合适的结构,在第一级采用双端输入、单端输出结构,并用四个二极管作为输入保护电路。第二级使用共源电路,恒流源作为有源负载以提高增益。输出级采用B类推挽共漏放大器,其最大效率可达78.5%,完成了主电路的设计。另外为了提高电路在频率和温度较高时的稳定性,采用了外部密勒补偿和外部负反馈的方法。文章的最后对电路的重要参数如直流增益、相位裕度及转换速率等做了比较详细的分析与推导,并在SUN工作站上使用Cadence的模拟设计工具对电路进行了全面的仿真,仿真的结果达到了并优于电路的设计目标,从而很好地完成了该项目的设计。更多还原

【Abstract】 The first chip of integrated circuits of the world was made in the U.S. in 1959.In the followed 50 years,the design technology of integrated circuits has been developed enormously. As the nuclear module of the unit of analogue circuits,people pay more and more attention to it. Man has achieved greate progress in design of the low voltage operational amplifier.But in design of high voltage operational amplifier, there is less progress in the field of high voltage than in that of low voltage because of the limit of high voltage craft and the affect of removing heat.In recent years,in some field of high voltage appliance,such as motor control system, piezoelectricity sensor and the drive circuits in printers there is emergent need of high voltage operational amplifier.Thus it is a pressing task to design high voltage operational amplifer with good feature.The writing of my thesis is just focused on above problem.By hard studing the principle of operational amplifier and the endureness to high voltage and BCD and SOI high voltage craft,and through the employment of the Xfab craft of Germany ,a kind of double high voltage operational amplifer used in piezoelectric sensors and the computers and the interfaces of vacuum tube is designed in this thesis.The power voltage of amplifer is±175V,the output current is 60mA,the DC voltage gain is 106dB,the slew rate is 40V/uS and the power is 200mW.MOSFET output makes the high voltage amplifier to avoid the second breakdown limitation,it’s power dissipation keeps the minimum,the quiescent quota current of each amplifier is only 2 mA.The suitable structure is applied according to demand of the ircuit.In the first stage,the structure of double input port and one output port is applied,and four diodes are used to protect the import circuit.In the second stage,the common source circuit is applied,and the constant current source is used to be source load to prove the voltage gain.The push-pull common drain amplifer of class B is used in the output stage,and it’s giggest efficiency can be 78.5%.Thus the main circuit is complished.In addition ,in order to enhance the stability of the circuit in higher frequency and temperature,the method of out miller compensation and out feedback is taken.In the last part of the thesis,some important parameters such as DC voltage gain ,the phase margin and slew rate are analyzed and inferred carefully,and the general simulation to the circuit has be made by using the analogue design tools of Cadence in the SUN work platform,the results of simulation meets to and surpluses the demands of the circuit.Hence the design of the project has been accomplished successfully.更多还原