INVERTING CURRENT FEEDBACK OPERATIONAL AMPLIFIER AND ITS APPLICATIONS TO MOS-C CIRCUIT REALIZATION

Bu çalışmada, terslenmiş akım geri beslemeli işlemsel yükselteç (TAGBİY) olarak isimlendirilen bir aktif eleman tanıtılmıştır. TAGBİY'in CMOS gerçeklemeleri verilmiştir. Bu yapı bloğunun, devrelerin MOS-C gerçeklemeleri için çok uygun olduğu gösterilmiştir. Uygulama örnekleri olarak TAGBİY kullanan Tow-Thomas ve Kerwin-Huelsman-Newcomb süzgeçleri ile birinci dereceden tüm geçiren süzgeç ve salıngaç devreleri sunulmuştur. Teorik analizler PSPICE benzetim sonuçları ile doğrulanmıştır. In this paper, an active element called inverting current feedback operational amplifier (ICFOA) is described. CMOS implementations of ICFOA are included. It has been shown that this building block is very suitable for MOS-C realization of circuits. As the application examples, MOS-C implementation of Tow-Thomas biquad, Kerwin-Huelsman-Newcomb biquad, first order allpass filter and quadrature oscillator using ICFOA are presented. Theoretical analysis is verified by PSPICE simulations

A new model for voltage output charge-pump phase frequency detector in resonant inverter tuning loops

Resonant inverters mostly employ tuning loops based on a phase-locked-loop (PILL) circuit. Some commercially available PLL chips, frequently used in this application, include a voltage output charge-pump phase frequency detector (CP/PFD) rather than well-known current output CP/PFD, which complicates the analysis of the loop. We present a new model for voltage output CPIPFD and an analysis of a tuning loop, which uses this model. The proposed model employs the resistance multiplication approach, which is applicable for the circuits containing periodically operated switches. It is shown that a voltage output CPIPFD in conjunction with a simple low-pass filter can be modeled using a DC voltage source, a phase error controlled resistor and a filter capacitor for positive phase error (theta) values. For negative theta values DC voltage source is shorted and the sign of the resistance is reversed. The theoretical study is verified by experimental results

Realization of n-th order voltage transfer function using a single operational transresistance amplifier

A new configuration to realize the most general n-th order voltage transfer function is proposed. It employs only one operational transresistance amplifier (OTRA) as the active element. In the synthesis of the transfer fimction, the RC:-RC decomposition technique is used. To the best of the authors knowledge, this is the first topology to be used in the realization of an n-th order transfer function employing a single OTRA

Operational transresistance amplifier based first-order allpass filter with an application example

A new voltage-mode filter configuration is proposed. The presented topology uses single operational transresistance amplifier (OTRA) and can realize first-order allpass, second-order allpass and notch filtering functions. The proposed circuits are insensitive to parasitic capacitances and resistances due to internally grounded input terminals of OTRA. Low output impedance of the configuration enables the circuits to be cascaded without additional buffers. The theoretical results are verified with PSPICE simulations using a CMOS realization of OTRA. The feasibility of the proposed first-order allpass filter is illustrated on the design of a quadrature oscillator