PRECISION DIFFERENTIAL AMPLIFIER Russian patent published in 2010 - IPC H03F3/45 

FIELD: radio engineering.

SUBSTANCE: invention may be used as device for amplification of analogue signals, in structure of analogue microchips of various functional purpose (for instance, operational amplifiers (OA) with low values of zero shift EMF). Precision differential amplifier (PDA) comprises input differential cascade (DC) (1) with the first (2) and second (3) collector outputs, output transistor (T) (4), emitter of which is connected to output (5) of PDA and circuit of static mode establishment (6), circuit of active load comprising the first T (7) and the second T (8) with combined bases, collector of the first T (7) is connected to the first (2) current lead of DC (1), collector of the second T (8) is connected to the second (3) current lead of DC (1). Circuit comprises additional T (9), base of which is connected to collector of the first T (7), emitter is connected to combined bases of the first T (7) and second T (8) via the first (10) additional source of voltage shift (VSS) and connected to source of reference current (11), and emitter T (4) is connected to output (5) of PDA via the second (12) of VSS, besides, voltages on the first (10) and second (12) of VSS are selected based on expression where is voltage of PDA supply source; U_eb.4 - voltage between emitter and base of output T (4) (U_eb≈0.7÷0.8 V); E₁₀ - voltage on the first (10) VSS; E₁₂ - voltage on the second (12) VSS.

EFFECT: reduced zero shift voltage.

3 dwg, 1 tbl