The Principle And Application Of Current Feedback Amplifier

Current Feedback Operational Amplifier (abbreviation: CFA) also is called transimpedance operational amplifier, it has very good performance advantage, and its ability that handles linearly big scope and high frequency signal is better than Voltage Feedback Operational Amplifier (abbreviation: VFA). CFA has good dynamic property that has broken through some traditional baffling problems for conventional VFA puzzle, have obvious practical and theoretical value, the huge interest that has aroused circuit and systematic academic circles.In this paper, the principle and design of current feedback amplifier (abbreviation: CFA) and its circuit about application have been studied. Firstly, the development of current mode circuit and CFA are briefly introduced. Secondly, with the topology and model circuit, this paper introduces the principle and loop characteristics of CFA. Then, the analogue signal processing and operation circuits with the active network elements using CFA have been induced overall: linear controlled sources, impedance transformer, amplifier, adder, integrator, differentiator and multiplier/division based on CFA. And a circuit of the earthing type general impedance transformer and a multiplier/division designed with CFA has been put forward. Based on the domestic and foreign research results the article proposed several second-order circuits: a second-order bandpass filter that can realize orthogonal control of ω_o and Q;a general filter circuit that can realize five filer functions from the same configuration, only changing impedances;another is a multifunction filter that may finish second-order filter and three-order filter only changing impedances. At the same time, this paper further proposes two high order filter circuits. The first circuit can realize lowpass and highpass filter, the other can realize lowpass, bandpass, highpass and notch filter. Both of them finish multifunctiona only changing impedances from the sameconfiguration. Finally, sine oscillators using CFA also have been introduced, a sine oscillation circuit using two CFA~s has been presented, which can realize independence adjustment about frequency and condition of oscillation. All filter and oscillator proposed are all proved by the PSpice simulation, the simulation results have been consistent with the theoretical analysis results.