SU1246340A1 - Differential amplifier - Google Patents

Abstract

The invention relates to radio engineering and electronics. The purpose of the invention is povplenie input resistance. The device contains four transistors (T) 1, 2, 3 and 4, two current sources (IT) 5 and 6, and two 5x0 equivalent current generators (UGT) 7 and 8. When a differential signal appears at the device inputs, through T 1 and 3 flow the same currents. Because the current gains at T 1 and 3 are equal, then their base currents are equal, which are mutually subtracted and do not consume current from the input source. The collector current T 3 controls the UGT 8 and repeats at its output, subtracting part of the current of the IC 6. Since As IT currents 5 and 6 are equal, then the base currents T 2 and 4 are also equal, which are mutually subtracted and also do not consume current from the input source. The goal is achieved by the introduction of UGT 8. 1 Il. § SP with N3 O) 4

Description

The invention relates to radio engineering and electrical engineering, in particular to differential amplifiers.

The purpose of the invention is povdenie input resistance.

The drawing shows a circuit diagram of a differential amplifier.

The differential amplifier contains the first 1, second 2, third 3, and fourth 4 transistors, the first 5 and second 6 current sources, the first 7 and second bushing current generators.

Differential amplifier works as follows.

The first 1, second 2, third 3 and fourth 4 transistors are selected with the same current gain, and the first and second current sources 5 and 6 are selected with equal currents.

When a differential signal is added to the inputs of a differential amplifier, one of the transistors, for example, the first transistor 1, opens up more than the second one. Accordingly, the i-its collector current rises, which is controlled via the control input of the first controlled current generator 7 by currents at its outputs. The control input currents of the first controlled current generator 7 are repeated at its outputs.

Thus, the same current flows through the third transistor 3 as well as through the eHergee transistor 1. As the current gains of these transistors are equal, their base currents are equal, and they are mutually subtracted and do not consume current from the input source. The collector current of the third transistor 3 controls the second controlled gene

Editor N. Bobkova

Compiled by N. Dubrovska

Tehred L.Oleynik Proofreader M. Demchik

Order 4020/54 Edition 816 Subscription

VNGOSHI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab, d. D / 5

Production and printing company, Uzhgorod, st. Project, 4

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Ratio 8 and repeats at its output by subtracting a part of the current of the second source 6 of the current. Since the currents of the first current source 5 and the second current source 6 are equal, the current through the fourth transistor 4 is equal to the current through the second transistor 2, their base currents are mutually subtracted and also do not consume current from the input source.

Claims (1)

Invention Formula A differential amplifier with a balanced input and a single-ended output, the arms of which are made respectively on the first and second transistors having the same structure, with the collector load J3 as the first controlled current generator, the control input of which is connected to the collector of the first transistor, and the code to the collector of the second transistor , with the first current source in the common zmitter circuit of the first and second transistors, whose bases are connected to the bases of the third transistor and the fourth transistor, respectively, A common collector with an opposite structure, with a second current source introduced into the emitter circuit of the fourth transistor, characterized in that, in order to increase the input resistance, a second controlled current generator, the input of which is connected, is introduced into it with the collector of the third transistor, and the output with the emitter of the fourth transistor; the first controlled current generator is provided with an additional output that is connected to the emitter of the third transistor.