Accurate tunable current-mirror and its applications

Abstract

This paper proposes an accurate electronically tunable current-mirror circuit based on translinear type-A (Polarities Alternative) topology. This circuit is realized by only 6 transistors with BJT technology. A shunt-feedback buffer principle is used in order to regulate its emitter voltage of translinear part. For current mirror behavior, output and input currents are identical with a small error. Current-gain can be obtained by adjusting the ratio of the 2 particular current sources. This proposed circuit is using only 6 transistors for the simple structure. The analysis of input, output resistance and current-gain are depicted. An extra transistor is added for maintained the transfer minimum error which is also proposed. The constant bandwidth more than 40MHz of various current-gains can be obtained. From current output mathematic function, several applications such as current multiplier, current divider and tunable current mirror are certainly performed. Other applications are raised to confirm realistic applicable including squaring and square- rooting circuits. All characteristics and performances are carried out by PSpice for confirm their well operations. © 2008 IEEE.