Research On Current Mode Continuous Time Filter With Based On MOCCâ…¡ And MCCCâ…¡

A continuous time filter is a front subject in microelectronics, circuits and systems. It applies widely in communication, electronic measurement, instrument & cybernation. Especially, it has an important application in mixed signal appearance circuits of communication IC. Current filters based on MOCCII and MCCCII may become the most potential because they have large dynamic range, good linearity, high speed, low power, simple structures. The dissertation studies the realization method of MOCCII and MCCCII, the structures, realizations and design methods of second-order and high-order current mode filters based on MOCCII and MCCCII. The main achievements consist of following several aspects:(1) A novel CMOS MOCCII circuit is proposed based on the cross-coupled differential transconductor. The circuit has a simple structure, a low operation voltage and a high accuracy. After PSPICE simulation to the proposed circui when the power voltage is±2.5V, the current tracking error of the inverting terminal and non-inverting terminal is equal to 0.03 in the 60MHz when n is 10. When n is 50, the current tracking error of the inverting terminal and non-inverting terminal is 0.01.(2) A MCCCII circuit based on transconductance translinear circuit of bipolar transistors is proposed. The simulated results indicate that the circuit can work correctly when the power voltage is±5V, v_X/ v_Yis 0.98, I_Z1/I_X is 1.02, I_Z 2 /I_X is 1.02, I_(z1)|-/I_X is 1.03, I_(z2)|-/I_X is 1.03 .The circuit can promote application of current mode filters for this kind of MCCCII circuit has the properties of a simple structure, an easy realization.(3) In the aspect of second order filters, a KHN current mode filter, current mode filter with multiple inputs a single output, common second order filter, current mode filter with multiple inputs multiple outputs and filter whose parameters (natural frequency and quality factor) can be adjusted are proposed. Each structure can realize low-pass, band-pass, high-pass, band-stop and all-pass filters or several kinds of these filters. The KHN current mode MOCCII based filtering circuit is composed of tree MOCCIIs and six RC elements. It can realize low-pass, band-pass and high-pass filter outputs at one time. Its passive sensitivity is very low. The proposed universal current mode filter based on MOCCIIs can realize low-pass, band-pass, high-pass, band-stop and all-pass filtering outputs simultaneously. A kind of multiple inputs a single output filter based on MCCCIIs with minimum components are proposed. It can realize low-pass, band-pass, high-pass, band-stop and all-pass filters. The most important is that the natural frequency can be adjusted, so it is convenient to tunned.