Study On Active Filters Based On Multi-Input And Multi-Output Current Conveyor

In recent years, with the rapid development of communication technology and economy, the requirements and needs to the filter are also increasing constantly. As the third generation mobile communication(3G) is widely used and the fourth generation mobile communication(4G) came out, and the research of the fifth generation mobile communication(5G), the bandwidth of the filter is becoming wider and wider. Filters are required to have the characteristics of wider bandwidth, faster processing speed, more simple circuit structure, lower power consumption and so on. In order to solve the problem fundamentally, an effective method is to use the common active device, which is characterized by the low impedance, high voltage swing, high speed and wide band.First, a mixed mode biquad using the modified differential difference current conveyor(MDDCC) is proposed based on the multi-input and multi-output characteristics of the current conveyor in this paper. The filter has a simple circuit structure, it can process both the current mode signal and the voltage mode signal.The proposed circuit can realize the low-pass, band-pass, and high-pass filter characteristics meanwhile under these two mode. Moreover, this filter has a very low sensitivity in the device ideal condition and non ideal condition. Then, on the foundation of the first mixed mode biquad, a modified mixed mode biquad based on MDDCC is proposed in this paper. Compared to the original mixed mode biquad, the modified mixed mode biquad saves one MDDCC and one capacitor.But it also has the satisfactory characters which belong to the original filter.Next, a basic unit of the first order voltage mode filter is designed based on the port features of MDDCC, which can realize the high-pass and the low-pass functions. A basic unit of the voltage mode biquad is realized too, which can achieve the high-pass, the low-pass and the band-pass functions. Through the cascade method, The low pass, high pass and band pass functions of the three order Butterworth filters can be realized by cascading the first order basic unite and the biquad basic unite.Then a basic unit of the first order current mode filter is proposed in this paper,the basic unit can realize the low-pass and the high-pass characters separately by changing the different elements. Then, a basic unit of current mode biquad is designed, which can make the low-pass, high-pass and the band-pass performance come true. According to the cascade method, the third order Butterworth low-pass,band-pass and high-pass filters using a first order filter basic unit and a biquadbasic unit are realized through the cascade of different port. The fourth order Butterworth low-pass, band-pass and high-pass filters applying two biquad basic units can be designed through the cascade of different port, and high order filter based on more different basic units can be designed.In the end, the layout of MDDCC using the Cadence IC5141 is examined,which can complete the inspection of the DRC(Design Rule Check) and the LVS(Layout Versus Schematic). The layout is proved to be correct.To prove the feasibility of the proposed filter circuit, the PSPICE simulations are completed. During the simulation, the CMOS process parameters contain the TSMC(Taiwan Semiconductor Manufacturing Company) 0.18μm and the BSIM(The Berkeley short-channel IGFET model) 90nm: the two mixed mode filter circuits are simulated by90 nm CMOS process parameter, the voltage mode high order filter and the current mode high order filter are simulated by the 0.18μm CMOS process parameter. The results indicate that the proposed circuit is effective.Various modes filter based on current conveyor play an important role in the analog signal processing, which can realize the signal conversion and filtering by current mode, voltage mode and mixed mode. The filter has a wide range of applications in the field of microelectronics, automatic control and electronic measurement.