Optimization Design Of CMOS Operational Amplifier Based On MATLAB

Since the 20th century,with the rapid development and popularization of portable electronic equipment,the status of analog integrated circuits has also increased,and operational amplifiers are a vital part of analog integrated circuits.With the advancement of technology,the performance of operational amplifier has become more stringent,and the constraints to be considered in design are becoming more and more complex.Therefore,the optimization design of operational amplifiers is still a research hotspot nowadays,especially the chip size is decreasing,the density and operating frequency are increasing correspondingly,and the reduction of power consumption and noise is the focus of attention now.There are many ways to optimize the design of analog circuits.One is to treat the design optimization of analog circuits as a mathematical problem of finding the extreme value of the objective function under multiple degrees of freedom and multiple constraints,so that it can be optimized by using mature mathematical tools and software,such as MATLAB optimization toolbox.This method requires expressing constraints as analytical expressions.In the literature,this method is used to optimize the thermal noise of the MOS tube in the operational amplifier.This is because the thermal noise formula is simple,and it is easy to express its constraints as an analytical expression.However,the model of flicker noise is complex,so it is difficult to express its constraints as analytical expressions.Therefore,flicker noise has not been taken as an optimization index in the previous optimization design of analog circuits using the above methods.In this study,an auxiliary circuit is introduced to calculate the relationship between the integrated squared flicker noise voltage and the DC bias voltage,and this relationship is fitted into a polynomial,so as to realize that the constraint condition of flicker noise expresses the DC bias voltage as an analytical expression.The total noise optimization of the circuit is completed by using the MATLAB interior point algorithm.The transfer function also plays a vital role in the design and optimization of analog circuits.Its main zeros and poles determine the unity gain bandwidth and stability of the circuit.However,for multi-level complex circuits,there are many parameters,and it is very difficult to derive the transfer function manually,and the transfer function often contains hundreds,thousands or even more.Only the most important of these items are the factors that determine the circuit performance.Therefore,how to compare the relative sizes of different items,keep the most important items,throw away most of the unimportant items,and quickly derive and simplify the transfer function is a huge challenge.This research proposes to use MATLAB's symbolic operation ability to realize the rapid derivation and simplification of the transfer function.The method has high accuracy and high efficiency.Using the above method,based on CSMC 0.5?m process,the two-stage operational amplifier in the bandgap reference voltage module is designed with 5V power supply voltage,and the layout is drawn.