SU1332291A1 - Current source - Google Patents

Abstract

The invention relates to electrical engineering and can be used to power the bias circuits of electronic circuits. The purpose of the invention is to increase the coefficient of stabilization of the current flow. The device has two transistors 4, 5. The emitter transition of transistor 4 is connected: e parallel to the emitter circuit of transistor 1, the collector of transistor 4 is connected to the base of transistor 3 by the emitter of transistor 5, the base of transistor 5 is connected to the base transistor 2. If the supply voltage changes, the modes of operation of transistors 4 and 5, the increase of r, and the voltage at the output of transistor 2 KON; change; they are retired by increasing the voltage at the emitter junction of transistor 5. A high voltage is applied to the input of transistor 5,silt

Description

The invention relates to electrical engineering and can be used to power the bias circuits of various electronic circuits.

The aim of the invention is to increase the stabilization factor of the output current.

The drawing shows the principle-electric circuit of the current source.

The current source contains the first 1., second 2, third 3, fourth A and Fifth 5 transistors, first 6, second 7, third 8 and fourth 9 resistors and a diode-resistor circuit on diode 10 and resistor 11. Moreover, resistor 6 is connected between The power bus and collector connection point of the first transistor 1 with the base of the second 2- and with the base of the fifth 5 transistors, the collector of the fourth transistor 4 is connected to the emitter of the fifth 5 and the base of the third 3 transistors, the base of the first 1 and fourth 4 transistors are connected to the emitter transistor 2 through the third resist or 8, and with a common bus and with the emitters of the first 1 and fourth 4 transistors - through a second resistor 7 and a diode-resistor chain connected in parallel, the emitter of the third transistor 3 is connected to a common bus through the fourth resistor 9, and the collector - with an output terminal to connect the load. I

The current source operates as follows.

in a way.

The negative temperature coefficient of the current source is provided by connecting a resistor 7 in parallel with the emitter junction of transistor 1. The positive temperature coefficient of the current source is accomplished by connecting a diode-resistor chain in the same circuits. By adjusting the ratio of the currents through the resistor 7 and the diode-resistor circuit, a predetermined temperature compensation can be made. The collector of transistor 2 is one of the outputs of the current source. However, it is limited to the range of current values, as well as to the acceptable minimum voltage. The connection of transistors 4 and 5 allows to reduce the voltage and to ensure the transfer of temperature-stabilized voltage to the current source on the transistor 3. Moreover, the choice of transistors 4

five

and 5, similar in area to the emitter junction of the transistor 1, compensation for the temperature dependence of the emitter junction of transistor 1 is achieved. A temperature change in the emitter current of transistor 4 equal to the change in current in transistor 1 creates the required change in the voltage drop at the emitter junction of transistor 5. Due to this on the base of transistor 3, a stabilized voltage equal to + Ujj is released, and through the collector of the transistor. 3 current flows

 I У1г. :: У1,. Rj

Rq rq

()

0

five

Where

m

and.

R

the voltage drop across the emitter junction of transistor 2 (3); the current flowing through the resistor 9;

resistances of resistors B (9). The choice of the geometry of the transistor 3, i.e. emitter junction area depending on the required value of the source current

1kz

I. aOI

0

uh 92 -1

receive

I value

KZ

rav

IfR.

In addition, the temperature-stabilized voltage can also be removed from the emitter output of the transistor 3.

An increase in output current stability when the supply voltage changes occurs by changing the operating modes of transistors 4 and 5. This causes an increase in the voltage at the output of transistor 2 to be compensated by an increase in voltage at the emitter junction of transistor 5. As a result, the voltage stability the input of the transistor 3 is obtained higher than in the known current source.

The proposed device, in comparison with the known, has a higher stability of the output current in a given temperature range when the supply voltage changes.

Claims (1)

Invention Formula Current source containing three transistors, four resistors, diode 1332291 but the resistor chain, the first with the output output, is different; the resistor is connected between the power supply bus u and with the fact that, for the purpose of raising and connecting the collector, the first stabilizer of the output transistor with the base of the second transistors current, the fourth transistor is connected in parallel with the emitter junction, the emitter transistor includes the second resistive junction of the fourth transistor, the torus and the diode-resistor circuit, is connected in parallel with the emitter peer of the second transistor through the transistor The first transistor, the third resistor collector is connected to the base of the first Q fourth transistor connected to the base transistor, the third emitter of the third transistor and the emitter of the fifth transistor is connected to the common bus transistor, and the base transistor of the first transistor through the transistor is connected to the base of the second transistor - the fourth resistor, and its collector - the resistor.