DIFFERENTIAL AMPLIFIER WITH INCREASED AMPLIFICATION COEFFICIENT AT LOW-OHMIC LOAD Russian patent published in 2011 - IPC H03F3/45 

FIELD: electricity.

SUBSTANCE: invention can be used as amplification device of analogue signals, in structure of analogue microcircuits of various functional purpose (e.g. SiGe-operational amplifiers (OA), comparator units, voltage stabilisers, various analogue-digital interfaces, etc.). Differential amplifier includes the first (1) and the second (2) input transistors (T) the collectors of which are connected to the first (3) power source (PS), the first (4) current mirror (CM) the base input (5) of which is connected to the first (3) PS through the first (6) pedestal current source (PCS); current output (7) of the first (4) CM is connected to the first (3) PS through the second (8) PCS and to base of the first (9) output T; inverting emitter input (10) of the first (4) CM is connected to emitter of the second (2) input T and through the third (11) PCS to the second (12) PS; non-inverting emitter input (13) of the first (4) CM is connected to the second (12) PS through the fourth (14) PCS and to emitter of the first (1) input T; the fifth (15) current-stabilising bipole is connected between output of device (16) and the second (12) PS; at that, collector of the first (9) output T is connected to the first (3) PS. To the diagram there introduced is the second (17) CM and the second (18) output T; base input (19) of the second (17) CM is connected to emitter of the first (9) output T; current output (20) of the second (17) CM is connected to emitter of the second (18) output T; common emitter output (21) of the second (17) CM is connected to output of device (16); collector of the second (18) output T is connected to the first (3) PS; at that, base input (5) of the first (4) CM is connected to the first (3) PS through in-series connected potential bias circuit (22) and the first (6) PCS; common node of in-series connected potential bias circuit (22) and the first (6) PCS is connected to the base of the second (18) output T, and potential bias circuit (22) is connected between base of the second (18) output T and base input (5) of the first (4) CM.

EFFECT: increasing amplification coefficient as to voltage of open DA by one or two orders when using relatively low-ohmic load bipoles.

5 cl, 12 dwg