SU1529410A1 - Current follower - Google Patents

Abstract

This invention relates to radio engineering and can be used in integrated analog devices. The purpose of the invention is to increase speed. Resistors 6 and 7 are introduced into the current repeater, containing five transistors 1-5, current source 8, busbars 9 and 10. The resistance value of the resistors 6.7 is chosen so that the voltage drop across them from the current flow of the I ₈ source 8 exceeded 4 ϕ _t / 100 mV), i.e. The potential input offset is 100–200 mV and its stability is determined by the stability of I ₈ . A repeater allows you to accurately convert the input current into a differential current with a common-mode output current independent of the input signal. Limit the input signal to a given level without the delays associated with the saturation of the transistors. 1 il.

Description

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The 10th and the invention relates to radio engineering and may be used in integrated analog devices.

The purpose of the invention is to improve speed.

The drawing shows a circuit diagram of a current repeater.

The current repeater contains the first

1, second 2, third 3, fourth 4, five transistors, first 6 and second 7 resistors, current source 8,

as well as the first 9 and second 10 power supply buses.

The current repeater works as follows.

The difference of the current through the current follower causes the difference of the fall voltage} P1 nl resistors 6 and 7, which, in turn, causes the difference between the currents of transistors 2 and 4. At the same time, the sum of the currents of transistors 2 and 4 remains equal to m (source 8 (neglected is given by the bap current of transistor 5). Since the emitters of transistors 1 and

2,3 and 4 are connected, then the current of transistor 1 is equal to the current of transistor 2, and the current of TpaHfii iCTopa 3 - to the current of transistor

4, These currents change until the voltage across the resistors 6 and 7 is not disconnected. Thus, (1 "+ + 1) - (, + 1) MBX where is the emitter current of the corresponding transistor; Ll

  input current difference.

or

one

Ig + UI6I./2

Jj I lBi / 2 M - 2

The difference in input currents is converted into a differential output current, and you can send a signal both to one input and to both (differentially). The maximum output signal is limited by the magnitude of the current Ig source I. The resistance value of the resistors 6 and 7 is chosen so that the voltage drop across them from

Ig current flow exceeded 4 "-Tt

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0 5

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(UOMV), i.e. The potential input offset is 100–200 mV and its stability is determined by the stability 1.

A current repeater allows you to accurately convert the input current into a differential with no dependence on the input signal with the common-mode output current.

A current repeater allows you to limit the input signal at a given level without the delays associated with the setting of transistors.

A low potential input bias improves accuracy when operating from an input source with a low output impedance (for example, if the input current is set from a voltage source through a resistor).

Claims (1)

Invention Formula A current repeater containing the first Bbrfi, second, third, fourth, fifth transistors having one structure, and a current source connected between the first power supply bus and the collector of the fourth transistor connected to the base of the fifth transistor whose emitter is connected to the bases of the first the second, third and fourth transistors, characterized in that, in order to improve speed, the first and second resistors are connected between the second power supply bus and the emitters of the second and fourth transistors, respectively but, the collectors of the second and fourth transistors are connected, and the emitters are connected to the emitters of the first and third transistors, respectively, being the differential input of the current follower, the differential output of which is the collectors of the first and third transistors, and the collector of the fifth transistor is connected to the first source bus nutrition , Water chin Editor L.Pcholinsk Tehred L. Serdyukova Proofreader I. Nuska Order 7738/54 Circulation 884 Subscription VNIIPI State Committee for Inventions and Discoveries under the USSR 113035, Moscow, Zh-35, 4/5 Raushsk nab.