SU743201A1 - Device for setting logic elements to initial state - Google Patents

Description

(54) DEVICE FOR INSTALLATION OF LOGICAL ELEMENTS IN THE INITIAL CONDITION

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The invention relates to digital technology and automation and can be applied in digital devices and devices.

A device for setting the logic elements to the initial state, containing an integrating chain, a trigger with an emitter connection and a key stage on transistors and resistors 1, is known.

However, the known device does not reset the logic elements when the voltage is turned off.

It is also known a device for setting logic elements to their initial state during supply voltage interruptions, comprising transistors, diodes, resistors, a zener diode and a capacitor 2.

The disadvantage of it is the complexity of the circuit.

The purpose of the invention is to simplify the device.

To achieve this goal, the device for setting the logic elements to initial state during supply voltage interruptions, containing the first and second power supply buses, resistors, a zener diode, a capacitor and a transistor of the first conductivity type, whose collector is connected to the first power supply bus through the first resistor , the emitter is connected to the tire to which the first lining is connected. the capacitor and the first output of the second resistor, and the base through the third resistor to the common bus and through the Zener diode and the fourth resistor to the bus of the second power source, the newly introduced diode in the switch in the right direction relative to the second power source between the common point of the fourth resistor and the stabilizer, throne and the second capacitor plate, which through the first newly introduced 20 resistor is connected to the common bus, the collector of the transistor of the first conductivity type through the second again introduced resistor is connected to the base again ennogo transistor vtoro25 first conductivity type whose emitter is connected to the bus of the first power source, the collector - to the second terminal of the second resistor and the output bus, and the newly introduced through the third resistor - to the base of the transistor of the first conductivity type.

The drawing shows the principal circuit design.

The collector of transistor 1 of the first conductivity type is connected via resistor 2 to bus 3 of the first power source, the emitter to common bus 4, to which the first capacitor plate 5 and the first pin of resistor b are connected, and the base through resistor 7 to common bus and through ; ± ron 8. and resistor 9 to the bus 10 of the second power source, the newly introduced diode 11 is connected in the forward direction relative to the second power source between the common point of the resistor 9, the zener diode 8 and the second capacitor plate 5, which through the first again entered resisto p 12 is connected to the common bus 4, the collector of the transistor 1 of the first conductivity type is connected via the second newly introduced resistor 13 to the base of the newly introduced transistor 14 of the second conductivity type, the emitter of which is connected to the bus 3 of the first power source, and the collector to the second output of the resistor 6 and to the output bus 15, and the newly introduced resistor 16 - to the base of the transistor 1 of the first conductivity type.

The device works as follows.

When the supply voltages of the power sources are turned on, the capacitor 5 is charged through the resistor 9 and diode 11, the voltage on the closed zener diode 8 grows, and the transistor 1 is closed and holds the closed state of the transistor 14. A low voltage level is removed from the circuit resistor B. resetting the logic elements.

With a further increase in the voltage across the capacitor 5, the Zener diode 8 pierces, which causes current to flow through the resistor 7 and the transition of the base-emitter of the transistor 1, Transistor 1 opens, the collector current flows through the resistors 2 and 13, and opens the transistor 14. From resistor 6 high voltage level is removed, allowing operation of logic devices. When the supply voltages are turned on, the voltage on the Stable 7T1Trone 8 decreases, the positive potential of the capacitor 5 closes the diode 11, which causes the transistor 1 to turn off. Transistor 14 closes and the initial state of the logic elements is set. Similarly, the installation of logic elements in the initial state occurs when the source Y is broken or short-circuited. The resistor 12 serves to discharge the capacitor 5 during interruptions of the supply voltage. Resistor 16 is required to increase the steepness of the fronts of the generated pulses by introducing positive feedback when switching transistors 1 and 14..

It is possible to use the proposed device in the presence of differently polarized or galvanically-developed first and second power sources by eliminating direct contact of the base of the main transistor 1 with the zener diode 8 using an additional optoelectronic pair, for example, a diode optocoupler,

5, the anode of the radiation diode of the optocoupler is connected to the anode of the Zener diode 8, and the cathode of the radiation diode is connected to the negative pole of the second power source, the anode of the photodiode is connected to the base of the main transistor 1, and the cathode is connected to the positive pole of the first power source.

The proposed circuit of the device, for setting the logical elements to the initial state during interruptions of the supply voltage, is simple, has a smaller number of elements and, consequently, a lower Q cost, dimensions, consumption and higher reliability compared to the known efficiency of its function. .-tiy. .

Claims (2)

1. Japanese Patent No. 45-1901-1, class H 03 K 19/00, 1970. 2. USSR author's certificate No. 450364, cl, H 03 K 19/08, 1973.