【作者】 滕颖；

【导师】 姚素英；

【作者基本信息】 天津大学 ， 微电子学与固体电子学， 2007， 硕士

【摘要】 本文研究了单片集成RC有源滤波器的设计问题,所提出的设计方案具有低电压、体积小,和CMOS工艺兼容,便于集成,参数调节灵活,中心频率稳定等诸多优点。文中比较系统地介绍了单片集成RC有源滤波器设计中的关键问题:滤波器系统函数的逼近方法以及在此基础上发展出的极点定位算法,使我们可以在得到滤波器指标后方便地得出所需要的传递函数;使用Tow-Thomas电路结构作为滤波器的核心单元,不仅使设计适用于多种不同的滤波要求,而且极大地方便了滤波器的参数调整;讨论了放大器的直流增益、单位增益带宽、摆率和动态范围等各项性能对滤波器相关指标的影响。针对中心频率在100范围内的应用,完成了主要电路设计,通过了仿真验证并绘制了版图。kHz～300kHz本论文的创新点在于:提出了用Mathematica求解复杂电路的符号传递函数并将其因式分解的方法,这为高阶滤波器电路设计提供了很大的方便;同时,本文还提供了将轨到轨运算放大器应用在滤波器的设计中,取代了以往工业中使用带零阈值电压输出级运算放大器的的做法,这种设计实现了在普通工艺下增加滤波器的动态范围的设计构想。在采用双电源的情况下,滤波器所能接受的信号幅度即为电源电压,同时这种设计因为省掉了跟随器,因此具有降低功耗并节省芯片面积的优点。使用Tow-Thomas二阶节作为滤波器的核心电路,只需调节部分无源元件即可将滤波器作为低通、高通、带通滤波器使用,并可以自行设定中心频率,极大地方便了使用。同时针对以Tow-Thomas电路模块作为核心单元的滤波器设计,本论文详细分析了放大器的增益带宽积对滤波器各性能参数如通带增益、品质因子Q值以及截止频率的影响,这为晶体管级电路设计和顶层的系统设计之间建立起了联系,量化了底层设计对上层参数的影响,为滤波器的集成设计提供了理想的解决方案。更多还原

【Abstract】 In the thesis, a design method which has advantages of less layout consuming, compatible with CMOS process, easy to be integrated, convenient for adjusting the parameters and steady central frequency is presented. The key issues about the design of monolithic integrated active RC filter are discussed. It includes the discussions of the main method for approximation and deduces the pole-placement algorithm which has been used to facilitate the design; Tow-Thomas circuit is used as the circuit building module not only for multiple usage but also for convenient parameter adjusting; the influences of the DC gain, bandwidth, slew rate and danamic range of the amplifier on the filter performance are discussed. A centeral frequency ranged monolithic active RC filter is designed and validated with simulation. The layout is finally given out. 100 kHz～300kHzIn the design, an innovation method of using Mathematica to calculate and factor the symbolic transfer function of the circuit, which graeatly facilitate the design. The rail-to-rail opamp is bringed forward to be used in the design of filters to get rid of the follower with zero-threshold transistor used as the output stage of the opamp. It not only enhances the dynamic range of the filter but also save power consumption and layout area.Tow-Thomas biquad was used as the core circuit of the filter, so that it can be used as a lowpass, bandpass, or highpass filter in the need of adjusting the off-chip passive components. The influences of the gain bandwidth of the opamp on the parameters such as passband gain, quality factor Q and central frequency of Tow-Thomas filter is discussed. This established the relationship between the transistor level and the top level circuit design and bridges the gap between system and transistor level in monolithic integrated active RC filter design.更多还原