Synthesis for Butterworth Filter using Compact VDTA Based on Sallen- Key Topology

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Author(s): Yong An Li*.

Journal Name: Recent Advances in Electrical & Electronic Engineering
Formerly Recent Patents on Electrical & Electronic Engineering

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Background: The original filter including grounded or virtual ground capacitors can been synthesized by using the NAM expansion. However, so far the filters including floating capacitor, such as Sallen-Key filter, have not been synthesized by means of the NAM expansion. This is a problem to be researched further.

Methods: By using the adjoint network theory, the Sallen-Key filter including floating capacitor first is turned into a current-mode one, which includes a grounded capacitor and a virtual ground capacitor. Then the node admittance matrix, after derived, is extended by using NAM expansion.

Results: At last, one VDTA Sallen-Key filter is received. It employs single compact VDTA and two grounded capacitors.

Conclusion: A Butterworth VDTA second-order frequency filter based on Sallen-Key topology with fo=100kHz, HLP=-HBP=1, is designed.

Keywords: Current-mode circuit, Sallen-Key topology, Butterworth filter, VDTA, Adjoint network theorem, Nodal admittance matrix expansion

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Article Details

(E-pub Ahead of Print)
DOI: 10.2174/2352096512666191004123213
Price: $95