High speed current mirror circuit and method

摘要

A current mirror circuit suitable for use as an amplifier active load having first and second MOS transistors connected in series together with third and fourth MOS transistors connected in series. The first and third transistors have common source and common gate connections, with the drain of the second transistor forming the current mirror input and the drain of the fourth transistor forming the current mirror output. Bias circuitry operates to maintain the second transistor in the triode region of operation and to maintain the fourth transistor in the saturation region of operation. The second transistor has a small geometry compared to the fourth transistor so as to enhance the transient response performance of the current mirror circuit.