Patent ID: 7075370

Claim:
A transconductance amplifier circuit comprising an operational amplifier having a dual polarity input gain stage coupled in cascade with an output stage, said dual polarity input gain stage having a first, non-inverting input to which a reference voltage is applied, and a second, inverting input, coupled over a feedback path to an input/output port of said output stage to which an input voltage is coupled, and first and second outputs, said output stage having a transimpedance circuit containing a first CMOS transistor pair having source-drain paths thereof coupled in series between said first and second outputs of said input stage, and gate inputs thereof coupled to receive prescribed DC voltages, and a transconductance circuit containing a second CMOS transistor pair having source-drain paths thereof coupled in series between first and second power supply terminals, and gate inputs thereof coupled to said first and second outputs of said input stage, and a third CMOS transistor pair coupled in parallel with said second CMOS transistor pair and forming therewith a pair of current mirror stages, and wherein a current output port of said transconductance amplifier circuit is coupled to a common connection of said third CMOS pair in the source-drain paths thereof.