有源电感的分析与设计

发布时间：2018-12-06 09:42

【摘要】：电感作为电路中最基本的元器件之一,不仅可以和电容构成选频网络,也应用在无线电收发机的各个射频模块(滤波器,低噪声放大器,功率放大器,混频器,压控振荡器等)中,具有实现阻抗变换,反馈,调谐,滤波等功能。正是因为电感的作用非常大,应用十分广泛,所以对电感的研究必不可少。而随着集成电路越来越趋于微型化,电感的参数特征使其在集成时的尺寸与品质因数无法满足使用要求,因而人们研究有源电感来解决无源电感尺寸与品质因素方面的矛盾。所谓有源电感,就是利用有源器件,电阻和电容组成的有源网络来模拟电感。有源网络按工作原理的不同可以分为两大类,反馈放大器类型和阻抗变换器类型。而对于有源电感的研究大部分都是基于阻抗变换器类型。设计有源电感电路的关键是回转器。理想回转器是一个二端口网络,具有倒逆特性。倒逆特性是可以把一个电容回转成一个电感或者把一个电感回转成电容的特性。当输入为一正弦电压,负载阻抗是一个电容元件时,回转器将电容回转成电感,称为等效电感。本文研究的有源电感是利用回转器的倒逆特性,设计基于运算放大器的有源电感电路和基于晶体管的有源电感电路。基于运算放大器的有源电感电路得出的电感值从毫亨到亨利级,其电阻达到几十欧到几千欧;在电感的质量方面,有源电感比一般电感更接近理想元件,应用于低频电路。如果当有源电感构成的电路需要运用到更高的工作频率时,运算放大器的增益带宽已经很难满足电路设计的要求。随着频率的进一步增加,增益急剧下降,电路的噪声逐渐恶化。因而采用传统的运放设计的有源电感,很难应用于高频。众所周知晶体管不仅可以作为放大器使用,并且其工作频率很高。因此,本文也研究了基于晶体管构成的有源电感电路。设计电路的基本原理是利用回转器的倒逆特性,将晶体管的本征电容回转为电感。用晶体管替代传统运放,设计的电路可以实现在兆赫兹甚至吉赫兹频率上工作的等效电感。采用晶体管设计的电路具有两个优点:晶体管的增益带宽很大,其特征频率可达到很高,能够满足高频工作的需求;晶体管与传统放大器相比,其噪声和功耗都比放大器低很多。设计出有源电感后,将设计出来的有源电感与电容进行串联和并联,构成谐振电路,测量其增益,相位,仿真其S参数,不仅验证了设计的电路可以等效为电感,还将其应用在谐振网络中。
[Abstract]:As one of the most basic components in the circuit, inductance can not only form a frequency-selective network with capacitors, but also be used in various RF modules (filters, low-noise amplifiers, power amplifiers, mixers) of transceivers. Voltage-controlled oscillator, etc., with impedance conversion, feedback, tuning, filtering and other functions. It is because the inductance is very big, the application is very widespread, so the research of inductance is indispensable. As the integrated circuit becomes more and more miniaturized, the parameter characteristics of inductor make the dimension and quality factor of inductor can not meet the requirement of application. Therefore, active inductor is studied to solve the contradiction between dimension and quality of passive inductor. Active inductance is an active network composed of active devices, resistors and capacitors to simulate inductance. Active networks can be divided into two categories according to their working principles: feedback amplifier type and impedance converter type. The study of active inductors is mostly based on impedance converter type. The key to design the active inductance circuit is the gyroscope. The ideal gyroscope is a two-port network with inverse characteristics. Inversion is the ability to turn a capacitor into an inductor or an inductor into a capacitor. When the input is a sinusoidal voltage and the load impedance is a capacitive element, the rotator rotates the capacitance into an inductance, which is called equivalent inductance. The active inductance studied in this paper is to design the active inductance circuit based on operational amplifier and the active inductance circuit based on transistor by using the reverse characteristic of gyroscope. The inductance obtained from the active inductance circuit based on operational amplifier ranges from milliheng to Henry grade, and its resistance reaches tens to thousands of ohms. In the quality of inductance, the active inductance is closer to the ideal element than the ordinary inductor, so it is used in low frequency circuits. If the circuit composed of active inductors needs to be applied to a higher operating frequency, the gain bandwidth of the operational amplifier is difficult to meet the requirements of the circuit design. With the further increase of frequency, the gain decreases sharply and the noise of the circuit deteriorates gradually. Therefore, the active inductors designed by traditional operational amplifier are difficult to be used in high frequency. It is well known that transistors can not only be used as amplifiers, but also work at high frequencies. Therefore, the active inductance circuit based on transistor is also studied in this paper. The basic principle of the circuit design is to turn the intrinsic capacitance of the transistor into inductance by using the reverse characteristic of the gyroscope. Using transistors instead of conventional operational amplifiers, the designed circuit can realize equivalent inductance working at MHz and even GHz frequencies. The circuit designed with transistor has two advantages: the gain bandwidth of transistor is very large, and its characteristic frequency can reach very high, which can meet the demand of high frequency operation; The noise and power consumption of transistors are much lower than those of conventional amplifiers. After the active inductance is designed, the designed active inductor and capacitor are connected in series and in parallel to form a resonant circuit. The gain, phase and S parameters of the circuit are measured and simulated. It is not only verified that the designed circuit can be equivalent to the inductance, It is also applied to the resonant network.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM55

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