Frequency self-compensated operational amplifier

摘要

An operational amplifier frequency self-compensated with respect to closed-loop gain comprises a transconductance input stage (2) and an amplifier output stage (3) connected serially together to receive an input signal (Sin) on at least one input terminal (IN) of the amplifier and generate an amplified signal (Sout) on an output terminal (OUT) of the amplifier. Provided between the input (2) and output (3) stages is an intermediate node (S) which is connected to a compensation block (11) to receive a frequency-variable compensation signal (Sc) therefrom. According to the invention, the compensation block (11) is coupled with its input to the input terminal (IN) of the amplifier. The compensation block (11) is connected to receive at least the feedback signal (Sf). Preferably, the compensation signal (Sc) is variable as a function of a gain value (Gcl) which is determined by the feedback circuit, and said variation of the compensation signal occurs in a relationship of inverse proportionality to the gain value. This invention is useful in discrete circuits whose operational amplifier forms a device by itself, as well as in fully integrated circuits. <IMAGE> <IMAGE>