SU681538A1 - Limiting amplifier - Google Patents

Description

The invention relates to radio engineering and can be used in radio engineering devices as an amplifier-limiting direct current with a low temperature drift.

A known limiting amplifier contains two two-emitter transistors connected in a differential circuit so that their first emitters are connected to a common bus l via a current generator.

However, this device exhibits significant dynamic temperature drift.

The purpose of the invention is to reduce the dynamic temperature drift.

To do this, the limiting amplifier contains two two-emitter transistors connected in a differential circuit so that their first emitters are connected to the common bus through the current generator, the second emitters of the transistors are connected to the common bus through appropriate additional current generators.

The drawing shows an electrical schematic diagram of the proposed device.

The limiting amplifier contains two two-emitter transistors 1 and 2,

3 current generator and two additional 4 and 5 current generators.

The device works the following; at once.

In the initial state, the powers i and dissipated in the collector transitions and their temperature are the same,

 If the input signal f exceeds the limit level, then

0 one two-emitter transistor 1 or 2 for the first emitter is locked, and the other for the first emitter is opened.

However, the power dissipated by

5 the collector junction, which is locked by the first emitter of the two emitter transistor 1 or 2, is not equal to zero, because a current flowing through the second emitter is set by the generator 4 or 5

0 current.

In this case, the currents of the generators 4 or b and 3 currents are chosen such that. so that the power dissipated at the col- lecting junctions of both two-sided transistors 1 and 2 at the time of the signal, are equal.

Consequently, the transition temperature of two emitter transistors 1

Claims (1)

0 and 2 will be the same. Thus, at the time of the signal, the temperature of the collector transitions of both two-emitter transistors 1 and 2 changes by the same amount, i.e. and the output voltage of both two emitter tranetis fTOpoB 1 and 2 varies in the same way; therefore, the difference dynamic temperature drift is zero. Claims of the Invention An Amplifier-Limiter, containing two two emitter transistors. included in a differential circuit so that their first emitters are connected to a common bus through a current generator, characterized in that, in order to reduce dingmic temperature drift, the second emitters of transistors are connected to a common bus through appropriate additional current generators. Sources of information taken into account in the examination 1. US patent 3742377, cl. H 03 F 3/68, 1973. 0 + e out oh