Parasitic Insensitive, Biphase Switched Capacitor Filters Realized With One Operational Amplifier Per Pole Pair

SUMMARYFour-port matrix theory is the foundation for various useful methods of analysing switched-capacitor networks. Thus, for example, signal-flow graph techniques, the link-two-port concept, and nodal computer analysis methods are based on either the four-port transmission or admittance matrix. In the derivation of these analysis techniques transmission, reverse-transmission, and transfer matrices are often used, but the relationship between them has not yet been clearly formulated for four-port networks. In this paper an attempt at formulation and clarification is made. Furthermore, it is shown that, once the considerable simplifications due to the presence of opamps are taken into account, a simple and elegant method of hand analysis for basic SC circuits using a combination of transmission and transfer matrix parameters results.

“…From (17) this is clearly not the case here. Similar observations are valid for the remaining expressions in equation (6).…”

Section: =0supporting

confidence: 71%

Section: Examplesmentioning

confidence: 99%

Elements of four‐port matrix theory as required for sc network analysis

Moschytz

1987

On a family of new two‐op‐amp switched‐capacitor biquads for high‐frequency applications

Mulawka

Konczykowska²,

Bon³

1990

This paper presents three novel biquads derived by applying the concept of so‐called basic elements for switched‐capacitor (SC) circuits. These biquads are without continuous feedback and comprise two op‐amps. They were derived assuming a transfer function denominator of the same form as the Fleischer‐Laker type E circuit. It is shown that by a simple modification of the switching arrangement, i.e. by changing the type of the basic SC element, the effect of the amplifier finite gain on the performance of SC filters can be significantly reduced. the efficiency of this approach has been established by extensive simulation studies using the dedicated symbolic analysis program SCYMBAL. Design equations and comparison with already known biquads of this type are presented. Examples are provided to demonstrate that the proposed circuits require a low total capacitance while finite‐gain effects are considerably reduced.

A family of modular fully differential witched capacitor filters for simulating ladder filters

Said

Hosny

Sobhy

1995

SUMMARYThe switched capacitor filters proposed in this paper are based on the simulation of LC ladder filters through the state variable equations. They include all-pole and finite transmission zero, lowpass filters, bandpass and highpass filters. The introduced family of filters has a fully differential structure; consequently it has the advantages of improved power supply and common mode rejection ratios and extended dynamic range. Since the proposed family of filters simulates LC ladder filters, it inherits their low passband sensitivities. One of the main advantages of this family of filters is that it has a modular structure composed of key and auxiliary circuits. This modular structure results in easier design and implementation procedures in VLSI fabrication. The double-sampling concept is applied to the introduced modular blocks, which is essentially needed in high-frequency applications. A comparison with similar published work available in the literature is presented and illustrative examples are given.