DIFFERENTIAL OPERATIONAL AMPLIFIER WITH LOW ZERO OFFSET VOLTAGE Russian patent published in 2011 - IPC H03F3/45 

FIELD: electricity.

SUBSTANCE: differential operational amplifier includes the first (1) and the second (2) input transistors (T) the emitters of which are connected to collector of the first (3) auxiliary T, the first (4) and the second (5) output T the bases of which are connected to offset voltage source (6), and emitters are connected through the first (7) and the second (8) current-stabilising bipoles to the first (9) power source; emitter of the first (4) output T is connected to collector of the first (1) input transistor, and emitter of the second (5) output T is connected to collector of the second (2) input T; current mirror (10) the input of which is connected to collector of the first (4) output transistor; output is connected to collector of the second (5) output T and base of input T (11) of output emitter repeater (ER); the second (12) and the third (13) auxiliary T the bases of which are connected to base of the first (3) auxiliary T; collector of the second (12) auxiliary T is connected through the third (14) current-stabilising bipole to the first (9) power source; collector of the third (13) auxiliary T is connected to output of device (15) and emitter of input T (11) of output ER the collector of which is connected to the first (9) power source; at that, emitters of the first (3), the second (12) and the third (13) auxiliary T are connected to the second (16) power source and common output of current mirror (10) through the fourth (17), the fifth (18) and the sixth (19) current-stabilising bipoles respectively. To the diagram there introduced is the first (20), the second (21) and the third (22) additional T the emitters of which are connected to bases of the first (3), the second (12) and the third (13) auxiliary T; bases are connected to collector of the second (12) auxiliary T; collector of the first (20) additional T is connected to emitter of the first (4) output T, and collectors of the second (21) and the third (22) additional T are connected to the first (9) power source.

EFFECT: reducing systematic component of zero offset voltage U_offset, its temperature and radiation drift.

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