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Proceedings ArticleDOI

The characteristic comparison of fully differential switched capacitor biquads

08 May 1989-Vol. 3, pp 1712-1715
TL;DR: Several fully differential (FD) switched-capacitor (SC) biquadratic circuits are presented and a systematic design procedure and several properties are described.
Abstract: Several fully differential (FD) switched-capacitor (SC) biquadratic circuits are presented. A systematic design procedure and several properties are described. The linear relationship of the capacitor spread as well as total capacitance to the finite quality factor Q in each biquad in terms of bandpass filter is discussed. >
Citations
More filters
Patent
Damien McCartney1
15 Feb 1994
TL;DR: In this paper, a switched-capacitor auto-zero integrator includes and integrator circuit and a correction circuit, where the integrator is any circuit including an operational amplifier having an input line and an output line, an input capacitor coupled to be charged by an Input voltage, and at least one integrating switch operable during an integrating time interval to connect the input capacitor to the integrating capacitor such that the integrated capacitor is charged to compensate for charge of the input capacitance.
Abstract: A switched-capacitor auto-zero integrator includes and integrator circuit and a correction circuit. The integrator circuit may be any circuit including an operational amplifier having an input line and an output line, an input capacitor coupled to be charged by an Input voltage, an integrating capacitor coupled to the output line, and at least one integrating switch operable during an integrating time interval to connect the input capacitor to the integrating capacitor such that the integrating capacitor is charged to compensate for charge of the input capacitor. The correction circuit includes an offset capacitor coupled to the input line and at least one correction switch operable in an auto-zero sub-interval: and a correction sub-interval. The sub-intervals occur only during the integrating interval such that the offset capacitor is charged by an offset voltage and a gain error voltage of the operational amplifier during the auto-zero sub-interval and the offset capacitor is connected to a summing node between the input capacitor and the integrating capacitor during the correction sub-interval.

37 citations

Book ChapterDOI
01 Jan 2006
TL;DR: This chapter discusses switched-capacitor filters (SCF) and illustrates a generic block diagram of an SCF-based sampled-data filtering system in which the analog input signal is preprocessed by an anti-aliasing filter to eliminate the unwanted signals located beyond half the clock sampling frequency.
Abstract: This chapter discusses switched-capacitor filters (SCF). It illustrates a generic block diagram of an SCF-based sampled-data filtering system in which the analog input signal is preprocessed by an anti-aliasing filter (AAF) to eliminate the unwanted signals located beyond half the clock sampling frequency. The chapter describes the fundamental aspects of first-order and second-order active SCF. A generic first-order active SCF is a three-in-one filtering circuit that incorporates three different types of SCF: low-pass, all-pass, and high-pass. A second-order SC filter is realized using one of many approaches, depending on the application's requirements and the arrangement of the switches. The chapter discusses the design principles of high-order SCFs. The realizations of SCFs can be categorized into three basic groups: continuous-time filter emulations, SC ladder filters, and SFG-based ladder realization. The chapter provides a step-by-step design example of a sixth-order elliptical low-pass SCF. It also presents a brief introduction to high-frequency complementary metal-oxide semiconductor (CMOS) SCFs.

2 citations

Patent
09 Mar 1996
TL;DR: In this paper, a SC integrator has a first switch (1) and an integrator (2), which contains an amplifier (3) which is switched by a first circuit network (4).
Abstract: The SC integrator has a first switch (1) and an integrator (2), which contains an amplifier (3) which is switched by a first circuit network (4). The network (4) connects the non-inverting output of the amplifier (3) via an integration capacitor (5) to the inverting input of the amplifier (3). A first terminal of a storage capacitor (6) is connected to earth. The second terminal of the storage capacitor (6) is connected to the non-inverting output of the amplifier (3) via a first switch (S1) and is connected via a second switch (S2) to the first switch (1). The first switch (1) contains a switching capacitor (7). The first terminal of the capacitor (7) is connected via a third and fourth switch (S3,S4) to earth and to the inverting input of the amplifier (3) respectively. Its second terminal is connected by a fifth switch (S5) to the input voltage and by a sixth switch (S6) to a further voltage potential. Also in the first circuit (1) is a connection via a seventh switch (S7) to a reference voltage (V ref). The second terminal of the storage capacitor (6) is connected by the second switch (S2) directly to the first terminal of the switching capacitor (7).

1 citations

References
More filters
Journal ArticleDOI
TL;DR: In this paper, the authors used an 80 MHz differential single-stage CMOS operational amplifier and a fully differential identical-resonator elliptic bandpass ladder filter configuration for communications applications.
Abstract: Bandpass filters for communications applications are realized using an 80 MHz differential single-stage CMOS operational amplifier and a fully differential identical-resonator elliptic bandpass ladder filter configuration. Experimental results are given for a CMOS sixth-order 260 kHz elliptic bandpass filter with a Q-factor of 40, a clock frequency of 4 MHz, and a power dissipation of 70 mW.

250 citations

Proceedings ArticleDOI
01 Dec 1981
TL;DR: Describes the implementation of a wide dynamic range voiceband switched-capacitor filter using a differential chopper-stabilized configuration and experimental results from a fifth-order low-pass voiceband prototype are presented.
Abstract: Describes the implementation of a wide dynamic range voiceband switched-capacitor filter using a differential chopper-stabilized configuration. The noise behavior of switched-capacitor filters is discussed qualitatively, and the effects of the chopper stabilization on the noise performance is analyzed. Experimental results from a fifth-order low-pass voiceband prototype are presented.

206 citations

Journal ArticleDOI
TL;DR: In this article, the authors focus on the amenability of various switched-capacitor (SC) options for high-frequency operation and compare them on the basis of analysis and a recent non-ideal SC network simulation tool.
Abstract: Biquad sections are the basic building block of practical switched-capacitor (SC) filters. The authors focus on the amenability of various biquad options for high-frequency operation. A comparison on the basis of analysis and a recent nonideal SC network simulation tool are confirmed by results from a VLSI 1.25-/spl mu/m CMOS test chip. A differencing-input SC biquad is shown to have a significant performance advantage over other circuits.

44 citations

Journal ArticleDOI
TL;DR: In this paper, three fully differential switched-capacitor (SC) circuit equivalents of the standard single-ended two-integrator loop are investigated for the implementation of the ladder networks generated by the exact design method of Datar and Sedra.
Abstract: Three fully differential switched-capacitor (SC) circuit equivalents of the standard single-ended two-integrator loop are investigated. Of particular interest is the use of these circuit blocks in the implementation of the ladder networks generated by the exact design method of Datar and Sedra.

12 citations

Journal ArticleDOI
TL;DR: In this article, all possible fully differential switched capacitor biquad circuits are presented and a systematic design procedure and comparison of their properties is given, and special attention is given to the high frequency performance of these circuits.
Abstract: All possible fully differential switched capacitor biquad circuits are presented in this work. Some of them have been presented by other authors. A systematic design procedure and comparison of their properties is given. Special attention is given to the high frequency performance of these circuits. Results show that as well as the known biquad circuits, there are others with comparable and in some cases better properties.

3 citations