scispace - formally typeset
Search or ask a question
Journal ArticleDOI

A systematic approach to the design of stray-insensitive SC circuits from active-RL or RLC prototypes

TL;DR: In this paper, a systematic approach to the design of stray-insensitive switched-capacitor (SC) circuits from active-RC or RLC prototypes employing a parasitic insensitive SC differential voltage-controlled current-source as a basic building block is attempted.
Abstract: A systematic approach to the design of stray-insensitive switched-capacitor (SC) circuits from active-RC or RLC prototypes employing a parasitic insensitive SC differential voltage-controlled current-source as a basic building block is attempted. Procedures for transforming active-RC and RLC circuits into stray-insensitive SC circuits are formulated and illustrated with typical examples. Restrictions on the pole-frequency and pole-Q of the SC biquad are derived so that it closely emulates the frequency response of the original active-RC biquad. the SC biquad and the ladder filter derived by the proposed procedures were simulated with discrete components and tested in the laboratory. Test results agree closely with the theoretical predictions.
Citations
More filters
Journal IssueDOI
TL;DR: In this paper, a systematic method for deriving CFA-based all-grounded-capacitor filters from current mode RLC prototype ladder is given, based on the operational simulation of node voltages and branch currents.
Abstract: A systematic method for deriving CFA-based all-grounded-capacitor filters from current mode RLC prototype ladder has been given. It is based on the operational simulation of node voltages and branch currents. It is extended to a voltage-mode ladder. These filters employ a minimum number of capacitors and minimum total capacitance. In some cases, all the capacitors can be made of equal value. Such filters are suitable for fabrication in integrated circuit technology. Illustrative examples for realizing generic filters are included with their simulation results. Copyright © 2007 John Wiley & Sons, Ltd.

21 citations

Journal ArticleDOI
TL;DR: In this paper, it was shown that by appropriate pairs of transformations on two subnetworks of a sinusoidal ocsillator feeding each other and consisting of linear passive elements and ideal operational amplifiers (OAs), 5 additional oscillators exhibiting the same oscillation frequency can be derived.
Abstract: It is shown that by appropriate pairs of transformations on two sub-networks of a sinusoidal ocsillator feeding each other and consisting of linear passive elements and ideal operational amplifiers (OAs), 5 additional oscillators exhibiting the same oscillation frequency can be derived. In special cases this number reduces to either 3 or 1.

4 citations

Journal ArticleDOI
TL;DR: In this article, an economical digitally programmable (DP) switched-capacitor (SC) biquad is proposed, which is stray-insensitive and can realize all of the five generic filters.
Abstract: An economical digitally programmable (DP) switched-capacitor (SC) biquad is proposed. It is stray-insensitive and can realize all of the five generic filters. Laboratory results agree with the theoretical ones.

3 citations

Proceedings ArticleDOI
04 Apr 2014
TL;DR: The aim of this paper is to present two biquads which meet the above requirements and use as small silicon area on the chip as possible.
Abstract: A good biquad filter, from practical point of view, should be capable of controlling the poles and zeros independently. In other words, it should be able to control pole frequency and pole Q and the type of generic filter independently. This calls for the control over the numerator and denominator coefficients by independent elements. Such circuits can then be programmed digitally. From economic fabrication point of view the biquad should use as small silicon area on the chip as possible. This is possible by reducing the total capacitance and/or resistance and number of OAs and time-multiplexing the components. The aim of this paper is to present two such biquads which meet the above requirements.
References
More filters
Journal ArticleDOI
TL;DR: A new technique to analog sampled data filtering is presented which can be fully integrated using MOS technology, and advantages of this new approach are reduced circuit complexity, low sensitivity to coefficient variations, and efficient utilization of silicon area.
Abstract: A new technique to analog sampled data filtering is presented which can be fully integrated using MOS technology. Advantages of this new approach are reduced circuit complexity, low sensitivity to coefficient variations, and efficient utilization of silicon area. Performance of monolithic low Q(Q=1) and high Q(Q=73) filters are presented which were implemented using NMOS technology. In implementing the high Q filter a new operational amplifier design was used which had a 14-V output range, rms noise voltage of 45 /spl mu/V, an open-loop gain of 6000, and a unity-gain bandwidth of 2 MHz.

282 citations

Journal ArticleDOI
TL;DR: In this article, two closely related, low-sensitivity, active switched capacitor fitter topologies are presented, which are immune to the various parasitic capacitances normally present in switched capacitor networks.
Abstract: Two closely related, low-sensitivity, active switched capacitor fitter topologies are presented. Each of these circuits comprises two operational amplifiers and at most nine capacitors. The topologies have been carefully constructed so that they are immune to the various parasitic capacitances normally present in switched capacitor networks. One filter topology is capable of realizing any stable biquadratic z-domain transfer function, while the second one is only slightly less than fully general. Most commonly used transfer functions can be realized with either topology and will require only seven capacitors. The choice between the two topologies will generally be made on the basis of total capacitance required, dynamic range behavior, and sensitivity. A complete set of synthesis equations is given for both circuits which cover both the general and all the important special cases of the biquadratic transfer function. Finally, several examples are given which illustrate the synthesis procedures and the versatility of the filter topologies.

278 citations

Journal ArticleDOI
TL;DR: In this paper, the authors describe design techniques for monolithic, high-precision, MOS sampled-data active-ladder filters, which are used to simulate doubly terminated LC ladder networks.
Abstract: Design techniques for monolithic, high-precision, MOS sampled-data active-ladder filters are described. Switched capacitor integrators are used to implement the "leapfrog" configuration for simulating doubly terminated LC ladder networks. Techniques are presented for designing all-pole low-pass filters, as well as methods for including transmission zeros. An approach for implementing bandpass filters is described which is derived from the conventional low-pass-to-bandpass transformation. Monolithic realizations for two different low-pass filters are briefly described which show excellent agreement with theory.

217 citations

Journal ArticleDOI
TL;DR: In this paper, a switched-capacitor filter is presented based on a pair of complementary integrators and has transfer functions independent of parasitic capacitances between any node and ground, and design equations are given for low-pass, bandpass, high-pass and notch biquads, as well as ladder simulation filters.
Abstract: New topologies for switched-capacitor filters are presented. The circuits are based on a pair of complementary integrators and have transfer functions independent of parasitic capacitances between any node and ground. Design equations are given for low-pass, bandpass, high-pass, and notch biquads, as well as ladder simulation filters. The ladder simulation filters are scaled for optimum dynamic range. Discrete prototypes of both cascade and ladder simulation filters are used to verify the theory.

188 citations

Journal ArticleDOI
TL;DR: The authors have demonstrated the advantages of ratioed capacitors for integrated active filters experimentally, using a specially designed integrated MOS test chip.
Abstract: The equivalence between resistor-capacitor (RC) filtering circuits and circuits containing switches and ratioed capacitors is examined. The authors have demonstrated the advantages of ratioed capacitors for integrated active filters experimentally, using a specially designed integrated MOS test chip. Polysilicon gate technology was used to fabricate the chip, with the capacitors being formed by two levels of polysilicon. For the theoretical description, and as a design aid, attention is drawn to the general equivalence between a resistor and a circuit element consisting of a capacitor and two switches. Nonideal effects, which set limits to the generality, are also discussed.

179 citations