Zdzislaw Czarnul

Common-mode feedback circuit with differential-difference amplifier

A common-mode feedback circuit suitable for fully balanced analog MOS structure realization is discussed. A novel scheme of differential-difference amplifier, the concept of which can be employed in CMFB system, is proposed. A transconductance amplifier is shown as an application example. SPICE simulation is used to verify the theory. >

Design of fully balanced analog systems based on ordinary and/or modified single-ended Opamps

The system architectures, which allow a high performance fully balanced (FB) system based on ordinary/modified single-ended opamps to be implemented, are investigated and the basic and general requirements are formulated. Two new methods of an FB analog system design, which contribute towards achieving both a high performance IC system implementation and a great reduction of the design time are presented. It is shown that a single-ended system based on any type of opamp (rail-to-rail, constant gm, etc.), realized in any technology (CMOS, bipolar, BiCMOS, GaAs), can be easily and effectively converted to its FB counterpart in a very practical way. Using the proposed rules, any FB system implementation with opamps (data converter, modulator, filter, etc.) requires only a single-ended system version design and the drawbacks related to a conventional FB system design are avoided. The principles of the design are pointed out and they are verified by experimental results.

Generalization of MRC circuits and its application

This paper proposes a generalization of MOS resistive circuits (MRCs). The proposed circuit has m inputs and n outputs while the conventional one has two inputs and two outputs. Applications of this generalized-version MRC to variable-gain amplifiers, integrators, and filters are presented to demonstrate its versatility as well as flexibility, HSPICE simulations using 2 /spl mu/m process parameters also confirm the effectiveness of the proposed circuit.

A low-voltage highly linear multiple weighted input CMOS transconductor

The authors discuss a highly linear multiple weighted input CMOS transconductor realization capable of low voltage operation. The proposed transconductor circuit can be implemented in several analog/digital systems to improve their parameters. >

Design of a novel linear 3-input CMOS OTA and its application to filter realization

A novel voltage-tunable linear 3-input CMOS Operational Transconductance Amplifier (OTA) suitable for on-chip integration of advanced monolithic system is described. When a 3-input OTA is needed, a conventional 3-input OTA uses two 2-input OTAs and grounds one of 4 input terminals. This paper presents a method to reduce the number of MOS transistors and to save chip area by designing a 3-input OTA directly. A CMOS pair technique is introduced as a solution to minimize a matching problem. Simulation results show that the active chip area of the proposed 3-input OTA is reduced by 23.7% compared to a conventional one. The proposed 3-input OTA is applied to a realization of an OTA-C filter to verify the effectiveness.

Topology-independent predistortion for integrator-based filters

This paper proposes a topology-independent predistortion for filters using integrators. This employs integrators having the same structure, the same-value elements and an electrically controllable unity-gain frequency and compensates for the deviation of frequency characteristics due to excess phase shifts of integrators without knowledge of a filter topology. The effectiveness of the proposed method is demonstrated through SPICE simulations.

Design automation for integrated continuous-time filters using integrators

This paper proposes a design automation for filters using integrators. This is based on a predistortion without knowledge of a filter topology. The predistortion requires an integrator having the same structure, the same-value elements and an electrically controllable unity-gain frequency, and compensates for the deviation of frequency characteristics due to an excess phase shift of an integrator. The effectiveness of the proposed method is demonstrated through SPICE simulations. An algorithm for a filter design automation is also discussed.

Principles of nonlinearity cancellation in linear MOS systems using MRC circuits

The general principles of nonlinearity cancellation in MOS systems with MRC circuits are presented. The application of this technique is investigated for MOST-only digital-analog converter implementation.<<ETX>>

Generalized MRC [MOS resistive circuit]

This paper proposed a generalization of MOS Resistive Circuits (MRC) which has m inputs and n outputs while the conventional one has 2 inputs and 2 outputs. Applications of this generalized-version MRC are resented to demonstrate its versatility as well as its flexibility. HSPICE simulations using 2 /spl mu/m process parameters also confirm the effectiveness of the proposed circuit.