Inverting Current Feedback Operational Amplifier Based A New Third Order Quadrature Oscillator Design

Oscillators are one of the most important basic circuit blocks frequently used in electrical-electronics engineering applications. Among several types of the sinusoidal oscillators, quadrature oscillators are frequently used in communication circuits, control and measurement circuits because they can give two signals with 90o phase difference from two different outputs. In the literature, there are quadrature oscillators realized from different active elements such as differential current transconductance amplifier (CDTA), operational transresistance amplifier (OTRA), second generation current conveyor (CCII) and differential voltage current conveyor (DVCC). In this work, a third-order quadrature oscillator circuit is presented by using an inverting current feedback operational amplifier (ICFOA), an active element that has attracted considerable attention in recent years. The topology consists of two ICFOA, three capacitors and three resistors by connecting a voltage mode secondorder low-pass filter and a voltage-mode integrator with a cascaded closed loop. The workability of the circuit is verified by PSPICE simulation program and it is seen that the simulation results verify the theory and the proposed circuit has good performance. The theoretical cut-off frequency is 0.792MHz and the cut-off frequency measured after the simulation is 0.800MHz. In the simulation, 0.35 μm MOSIS parameter set and ICFOA CMOS structure are used. The proposed circuit power consumption is 4.83mW. In this work, we present a new Quadrature Oscillator Design with an Inverting Current Feedback Operational Amplifier. Since the output quadrature oscillator circuit has low impedance, the proposed circuit can be connected without additional circuit as cascade. Thus, there is no difficulty in adapting to analog signal processing circuits. As a result, a quadrature oscillator was realized by obtaining a sinusoidal waveform with 90o phase difference between them.