SU1162035A1 - Logical element - Google Patents

Description

The invention relates to electronics and can be used in automation systems, such as railway transport, where the undetected failure in the logical 5

devices can lead to a dangerous situation.

Known logic device, made on the safe elements AND, OR, NOT [1]. ten

A disadvantage of this device is the presence in the circuit of a large number of transformers, the manufacture of which in the integrated design is not mastered, which drastically reduces the copying of their mass use and production.

The closest in technical essence to the invention is a logic element containing an amplifier, the output of which is connected to a voltage doubler rectifier, and the first channel consisting of a modulator made on an optocoupler, whose inputs are connected respectively to the 25 direct output of the information signal source and bus modulating signal [2]. .

A disadvantage of this device is the possibility of spurious signals appearing at its output in case of failure of circuit elements. In addition, this device performs only one logical function.

The purpose of the invention is to improve the reliability of the function and enhance functionality.

I

To do this, in the logic element containing the amplifier, the output of which is connected to the voltage doubler rectifier 40, and the first channel, consisting of a modulator made on the optocoupler, whose inputs are connected respectively to the direct output of the information source 45 and the modulating signal bus, to the first channel introduced the element And, performed on the opto-transistor2

A dongle with a transistor of the first conductivity type, the first input of which is connected to the modulator output, and the output to the channel output, is additionally inputted to the device a second identical channel, a “Bus” signal bus, and a logic unit running on an opto-transistor dongle with a second transistor conduction type, the blocking input of the logic block is connected to the "Block" signal bus; the information inputs are corresponding to the channel outputs, and the output is connected to the amplifier input; in each channel, the source of the information signal is made on the inverse the torus, the input of which is connected to the corresponding input of the device, the base of the first transistor of the first conductivity type of inverter is connected to the input of the inverter through the first resistor, the collector through the second resistor to the corresponding power supply bus, and the emitter to the common bus through the photodiode of the optocoupler whose photodiode is connected in series with the third resistor, the second pins of the photodiode and the third resistor are connected to power supply buses and respectively to the emitter and * through the fourth resistor to the collector , The second transistor of the first conductivity type which is connected _(in two oppositely-separating diode included Direct and inverted outputs of the inverter, the base of the second transistor conduction pervogo.tipa connected to the junction of the photodiode and the third resistor, and inverted output of each channel of the inverter is connected to the second input element And another channel, the amplifier is made according to a two-stage scheme, the phase inversion cascade of which contains two. a transistor of the first conductivity type And optically connected to a push-pull made on the transistors of the second conductivity type

3

1162035 4

cascade whose output is connected ⁴

to the output of the amplifier, and the base of the first

the transistor of the first type of conduction of the phase-inversion cascade is connected to the input of the amplifier.

The drawing shows a schematic diagram of a logic element.

The logic element contains an amplifier 1, made according to a two-stage scheme, the phase-inversion cascade of which contains two transistors 2 and 3 of the first type of conduction and is connected via optocouples 4.5 to a push-pull stage of transistors 6.7 of the second type of conduction, the output of which is connected to the output of amplifier 1 and to the voltage doubler rectifier 8, the first and second identical channels, each of which consists of a source, made on the inverter 9 of the information signal, a modulator 10, made on the optocoupler 11, whose inputs are from Connected respectively with the direct output of source 9 and bus 12 of the modulating signal and element 13 And, performed on the opto-transistor switch with the transistor 14 of the first conductivity type, the first input of the element 13 is connected to the output of the modulator 10, and the output to the channel output. In addition, the device contains a bus 15 signal "Ban" and logical, block 16, performed on the opto-transistor switch with the transistor 17 of the second type conducted by 35 ti. The inhibit input of the logic unit 16 is connected to the bus 15, the information inputs are connected to the channel outputs, and the output to the input of the amplifier 1, to which the base of the first transistor 40 2 is connected to a phase-inverse cascade. The source 9 is made on the inverter, the input of which is connected to the corresponding input 18 (19) of the device, the base of the first transistor 20 of the first type conducted by the * 45 inverter through the first resistor 21 is connected to the input of the inverter, the collector through the second resistor 22 of the corresponding power supply bus and the emitter is connected to the common bus through the LED of the optocoupler 23, the photodiode of which is connected in series with the third resistor 24, the second pins of the photodiode of the optocoupler 23 and the third resistor of the 24 are connected to the power supply buses of different polarities and respectively emitter and through the fourth resistor 25 to the collector of the second

ten

15

20

25

thirty

50

55

transistor 26 of the first conductivity type, which is connected via two oppositely connected separation diodes 27, 28 to the direct and inverse outputs of the inverter, the base of the transistor 26 is connected to the connection point of the photodiode of the optocoupler 23 and resistor 24, and the inverted inverter output of each channel is connected to the second input- element 13 And another channel.

The device "works as follows.

If the signal "1" is applied to the input 18, the first transistor 20 of the inverter 9 opens, the LED of the optocoupler 23, energized in the emitter circuit of the transistor 20 is energized, the reverse current of the photodiode of the optocoupler 23 increases under the action of its luminous flux, the transistor 26 opens and a circuit is formed for the current from negative power source through a displaced in the forward direction p - n junction of the separation diode 28.

If the signal "O" is applied to the input 18, the transistor 20 is closed, the LED of the optocoupler 23 is not excited, the reverse current of the photodiode of the optocoupler 23 is small, the transistor 26 is reliably locked by the bias voltage on the resistor 24, a circuit is formed for the current from the positive power bus through the forward-biased p and diode junction 27.

If the signal "1" is applied to the input 19, the first transistor 20 of the inverter 9 of the second channel opens, the included emitter circuit is excited, the emitting diode of the optocoupler 23 is energized, the reverse current of the photodiode of the optocoupler 23 increases under the action of its luminous flux, the second transistor 26 of the inverter opens 9 of the second channel, a circuit is formed for the current from the negative power supply bus through the forward-shifted p-j transition of the separation diode 28. If the signal 19 is supplied to the input 19 of the second channel, the transistor 20 is closed, there is no excitation current LED ode photocoupler 23, the reverse current of the photodiode is small, the second transistor 26 is closed the bias voltage across the resistor 24, the chain is formed for the current from the positive supply rail through a forward biased p - η transition diode 27.

If input 18 is present

level "0", and at the entrance 19 - level

five

62035

6

"1", the current flows through the isolating diode 27 of the inverter 9 of the first channel and the optocoupler switch of the element 13 of the first channel on the transistor 14 and the optocoupler 29, will start switching to the frequency of the modulating signal fed to the bus 12, and due to the current flowing through the separation diode 28 of the inverter 9 of the second channel, are created for switching the opto-transistor switch of the logic unit 16 on the transistor 17 and the optocoupler 30.

If the input level 18 is “1” and the input level 19 is “0”, then under the action of the currents flowing through the diode 28 of the inverter of the first channel and the diode 27 of the inverter of the second channel they switch with the frequency of the modulating signal of the opto-transistor 20 block 16 and the logic element 13 And the second channel on the transistors 17, 14 and optro on 30.29.

If on bus 15 of the "Inhibit" signal & there is a level "1", then the high-frequency signal from the optocoupler 30 of the logic unit 16 is fed to the input of the first transistor 2 of the phase-inverse amplifier stage, and is amplified and 30 is converted at the output of the logic element into a constant-level signal using a rectifier 8. If the inputs 18, 19 are the same signals ("1" or "0"), then regardless of the level 35 of the signal on bus 15 at the output of the element, the signal is "0". Thus, the "exclusive OR" function is implemented.

Due to the alternation of the polarity of the transistors optocoupler 40

the keys of adjacent stages (logic element 13 AND, logic unit 16 and stages of amplifier 1) dangerous failures in case of parasitic leaks are eliminated. For example, when combining the emitter of the transistor 14 with the cathode of the photodiode of the optocoupler 29, the transistor 17 will close with a positive potential of the power source and the output level will be "0". In case of breakdown or breakage of any element of the circuit due to alternation of polarity, there is no path of the high-frequency signal and the output of the device will also be the level "0". The inclusion of optocouple LEDs in the emitter circuits of key transistors provides a fixed, controlled element threshold equal to the sum of the voltage drops by}> - n LED transition and base-emitter transition -, -. ·. zistor The presence of the threshold eliminates the accidental operation of keys in terms of interference.

I

The logical element allows you to implement other logical functions with the exception of spurious signals at the output. So the function "3apret" is realized by the logical inputs 18.19 of the device when the output of the element 13 And the second channel is turned off. The function "And" is implemented by the first logic input 18 and the bus 15 signal "Inhibit". The function "OR" is realized when the inverted outputs of inverters 9 are disconnected from the second inputs of elements 13 AND in each channel and these inputs are connected to a negative voltage source.

1162035

Claims (1)

LOGICAL ELEMENT, containing an amplifier whose output is connected to a voltage doubler rectifier, and the first channel consisting of a modulator made on an optocoupler, whose inputs are connected respectively to the direct output of the information signal source and the modulating signal bus, characterized in that ^ of the reliability of operation and expanding the functionality, an And element, introduced on an opto-transistor switch, is introduced into the first channel with a transistor of the first conductivity type, the first input of which is connected to the modulator output, and the output to the channel output, is additionally inserted into the device a second identical channel "and logic block, executed on the _h optocoupler switch with the transistor of the second conduction type, the blocking input of the logic unit is connected to the "Ban" signal bus, information inputs are respectively connected to the channel outputs, and the output is connected to the amplifier input, while in each channel the source of the information signal is made on the inverter, whose input is connected to the corresponding input of the device , the base of the first transistor of the first conductivity type of the inverter is connected to the inverter through the first resistor, the collector through the second resistor to the corresponding power supply bus, and the emitter to the common bus through the light The diode of the optocoupler, the photodiode of which is connected in series with the third resistor, the second pins of the photodiode and the third resistor are connected to bipolar buses of the power supply and respectively to the emitter and through the fourth resistor to the collector of the second transistor of the first conductivity type, which is connected through two counter-connected separation diodes to the forward and inverted outputs of the inverter, the base of the second transistor of the first conductivity type is connected to the connection point of the photodiode and the third resistor, and the inverse output is inverted ora each channel is connected to the second input of the AND gate of the other channel, formed by two-stage amplifier circuit fazoinversny stage which comprises two transistors of the first conductivity type and is optically coupled to transistors formed on the second conductivity-type push-pull stage whose output is connected and „1162035 1162035 to the output of the amplifier, and the base of the first transistor of the first conductivity type of the phase-inversion cascade is connected to the input of the amplifier. one