SU1251018A1 - Current threshold device - Google Patents

Abstract

The invention relates to a pulse technique. It can be used in systems of automation, control, and sysilization. The purpose of the invention is to expand the functionality. To do this, the device containing the differential stage 1, two balanced transistors 1, 2, current generator 5, performed on transistor 6 and current-supplying resistor 8, input current source 4, first power supply bus 20, additional transistor 10, load resistor 19, additional current generator 12, diodes 15, 16 and new connections are introduced. The device not only captures the moment when the controlled current exceeds the threshold value, but also makes it possible to estimate how much this current is less or more than the threshold level. Additional information from the outputs 21 and 23 can be used to control the recording or measuring devices of the auto-igmatics and control systems. With the help of the current supply resistors 14 and 7 of the current generators in the device, the necessary threshold level I and the controlled range, 2 changes of the input current, are easily set. 1 il.

Description

The invention relates to a pulse technique and can be used in automation systems, alarm control.

The purpose of the invention is to expand the functional capabilities by providing an estimate of how many input currents are greater or less than the threshold level.

FIG. 1 presents the electrical circuit of the proposed device; in fig. 2 - timing diagrams for the operation of the device.

Differential cascade 1 of the current threshold device is made on the input balanced transistors

2 and 3, one of which is connected to the input current source 4, and the emitter circuit of transistors 2 and 3 includes a current generator 5, which is filled with transistor 6 and the current supply resistor 7. At the same time, the offset to transistor 6 is set by parametrical stabilizer 8, 9 voltage. The base of the second balanced transistor 3 differential cascade and the base of the additional transistor 10 are connected to a potentialless zero potential to which the output of the generator 5 is connected via diode 11, and the output of the additional generator 12 of the current produced by the transistor 13 and the current-carrying resistor 14 is connected to the emitter of the additional transistor 10, and through successively connected in the forward direction diodes 15 and 16, an additional generator 12 of the current is connected to the output of the generator 5, with the collectors of transistors 2,

3 and 10 through the load resistors 17, 18 and 19 are connected to the bus 20 of the first power source (+ E) and the output device 21, 22 and 23 of the threshold device.

The device works as follows.

Suppose that in the initial state the controlled current 1y is zero. Then the entire current of the additional current generator 12 flows through the additional transistor 10 and creates a resistor Rt9

torus 19 voltage drop U I ,. RI ,. The current of the generator 5 of the differential stage 1 flows through the balanced transistor 3, since the base of the transistor 2 as a result of the voltage drop at the zmitter junction of the additional transistor 10 is at a negative potential -Ur. Therefore, on the second

and to

The output 22 of the device, as well as the output 21, has a low potential Е „U, j, g, and at its output

you ,, G E. (Fig.21

23 - high potential

If the monitored current begins to gradually increase, it will cause

to a decrease in the current flowing through the auxiliary transistor 10. The voltage drop across the resistor 19 decreases and the potential at the output 21 of the device falls, and the voltage

at outputs 22 and 23 remain unchanged:

Shey

R ,,

(1 „- TJ-R,

nineteen

you

 F

bfi

P

- V,

Rl8

EGT I .- R

IS

The voltage at the output 21 Ug (, u reaches its maximum value at I, g. The current flow through the additional transistor 10 stops as this increases the potential of the emitter of the additional transistor 10 due to unlocking the diodes 15 and 16 and the excess current I) (Inop From the base of the balanced transistor 2 of the differential stage, the potential becomes positive:

five

0

and

-Ut

and.

 and.,. 0.5V,

-vg% 9.5 316 which leads to cascade switching: unlocking of transistor 2 and locking of transistor 3. The voltages at the outputs 22 and 23 abruptly change (Fig. 2a, 5).

A further increase in the monitored current 1u leads to an increase in the excess current flowing through diodes 15 and 16, and consequently, to a decrease in current through the balanced transistor 2. This causes a corresponding increase in potential at the output 23 of the current threshold device, which lasts until ; current i, i

Nin on thaw

 I, -. Output voltages of outputs 21 and 22 are always constant:

and

and.

Bbltj, BMX

l

(Inop

IT I.) U

3

When the monitored current 1 exceeds the measurement range equal to Inop O, the excess current I ,, - r7or g) starts to flow through the protective diode 11 ,. and on all three outputs of the device the maximum voltages are set:

9Sh „Gb1 ,,

"2,

 yy

Thus, the proposed device has broader functionality compared to the known ones, since it not only captures the moment of exceeding the threshold value monitored by the current (output 22), but also makes it possible to evaluate how much this current is less (output 21) or more (output 23) threshold level Additional information from the outputs 21 and 23 can be used to control the recording or measuring devices of automation and control systems. Using current-supplying resistors 14 and 7 of the current generators in the proposed device, the required threshold level and a controlled range of input current variation, which depend little on the instability of the supply voltage and the parameters of semiconductor elements, are easily established, which allows to expand the field of application of the device

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Claims (1)

Invention Formula A current threshold device containing a differential stage with a current generator in the emitter circuit of input balanced transistors, the first input of which is connected to an input current source, a power supply bus, an additional transistor whose collector is connected via a load resistor to the first power supply bus, and an additional current generator, characterized in that, in order to extend the functionality by providing the possibility of estimating how much the input side is more or less than the threshold level, diodes has been entered, the additional current generator output is connected to the emitter of the additional transistor and the first input of the differential stage directly, but through a series-connected in the forward direction of the first and second diodes are connected to the emitters of transistors balanced differential stage that through the third diode are connected to the bus zero potential connected to the base of the additional transistor and the second the input of the differential stage, while the control inputs of the current generator of the differential stage and the additional current generator are interconnected, and the input is additional. A current generator is connected to the second power supply bus. 7 L Compiled by N. Markin. Editor L. Pchelinska. Tehred N. Voicalo Order 4409/43 Circulation 836 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 Proofreader E. Roshko