Static and Dynamic Characteristics of Current-Current Converters Based on Push-Pull Amplifier

Abstract

In some cases, current amplifiers have an advantage over voltage amplifiers. This is due to the fact that a significant part of the parasitic parameters of integrated circuits are capacitances. In this case, it is necessary to take into account the fact that, according to the laws of switching, the voltage across the capacitor cannot change abruptly, while the current through the capacitor can change abruptly. Thus, when designing electronic circuits for various analog-digital and digital-analog accessories and systems, one should be guided by the principle of current amplification. For this, it is advisable to use converters — current-current amplifiers (CCA). Functional and schematic diagrams of a current-to-current converter with a grounded load with variable transmission coefficients based on a push-pull DC amplifier, the complexity of which is less known, are considered. The linearity errors and zero bias currents of the PPDA are estimated depending on the value of the transmission coefficients of a particular. It showed that the linearity errors do not exceed 0,001 %, and the bias current does not exceed 0,5 μA. This makes it possible to use these devices in high-frequency electronic systems and devices. The optimal values of the tuning resistor are determined, at which the linearity errors at the given transmission ratios are minimal. The dynamic characteristics of the PPDA are analyzed using the frequency response, phase response and transient response for the given current transfer coefficients. It is proved that the bandwidth is as wide as possible and is determined by the limiting frequency of the transistor amplification.