Researches On The Design Of Full-integrated Active Filters

With the development of the technologies of system on chip, integrated circuits and telecommunications, the design of full-integrated active filters has been paid great attention in recent years.In this dissertation, the international and national researches and development trends of the full-integrated active filters are systematically reviewed. The design technology of full-integrated active filters that based on the theory of network synthesis and signal flow graph is deeply studied.First, the macromodel of full-differential operational amplifier for circuit simulation is established, the construction method of new component and library model also is introduced. This essential step is required for verifying the correctness of full-integrated active filters which are designed in the dissertation.Second, based on the doubly terminated LC ladder prototype, whose magnitude response is extraordinarily insensitive to perturbations of the LC elements and to the terminating resistances, the detailed signal flow graphs of sixth-order Butterworth lowpass filter and fifth-order Butterworth highpass filter as well as sixth-order Chebyshev bandpass filter are derived respectively, the corresponding active RC filters based on inverting integrator and full-differential active RC filters are realized.Finally, the design examples and simulated results are given, which not only show the processes of the design of full-integrated active filters that based on signal flow graph, but also verify the validity and correctness of the given method. At the same time, in order to improve the dynamic range of full-integrated active filters, the method that scaling the output voltage of integrators in the circuits is used.The innovation points of this thesis include the realization of full-differential active RC highpass and bandpass filters that based on signal flow graph and the method of scaling the output voltage of integrators in the circuits, which expands the dynamic range of full-integrated active filters.