SU428556A1 - LOGICAL ELEMENT ON CURRENT SWITCHES - Google Patents

Description

one

The invention relates to the field of computer technology and digital automation and can be used to create a series of integrated circuits with emitter connections.

A logic element is known on current switches, the first of which contains n transistors, for example pn-type, with combined emitters and collectors, and the second current switch contains one transistor, for example, pn-type, at which the emitter is connected with the emitters of the transistors of the first current switch, and the base with the reference voltage bus.

The disadvantage of the known element is the inability by simple means to generate a pulse from the voltage drop one by one and, if necessary, to delay the signals through other inputs, resulting in heterogeneous components, which is unacceptable from the point of view of the integral technology, or component redundancy, which leads in turn, to an increase in the area of the base crystal and a decrease in the level of functional density when constructing trigger schemes with a counting input.

In order to expand the functionality, a charge-accumulating diode is introduced into the logic element, in which the anode is connected to the collectors of the transistors of the first current switch, and the cathode is connected to the base of one of the transistors of the first current switch and the gate signal bus.

The drawing shows the scheme of the proposed logical element.

The proposed logic element on the current switches consists of homogeneous components: transistors 1-5, resistors 6-9

and a diode 10, the anode of which is connected to the collectors of the input inverting transistors, and the cathode - to the base of one of these transistors and to the gate signal bus. On inputs a and b, to which allow or prohibitory voltage levels are applied, the circuit is controlled.

At the entrance to the operation, a transition is performed, i.e. the formation of a pulse from a voltage drop.

In the initial state, when applied to the inputs a, b and in the voltage level -, 5V, corresponding to a logical zero, at the reference voltage / 1V, transistors 1-3 are closed, transistor 14 is open. By chain consisting

from the resistor 6 and diode 10, current flows. The voltage across the collectors of transistors 1-3 and at the output of the emitter follower, respectively, is determined by the expressions

 in + diode And and 7th 9 ..

thirty

If the open diode voltage drops and the base-emitter junction of transistor 5 equals .0.75, the potential at collectors of transistors 1-3 is -0.8 B, and the output of the emitter follower is -1.55.

When applied at the input to the voltage drop from -1.55 to the level of -0.75, corresponding to a logical unit, the voltage level at the collectors of transistors 1-3 and at the output of the emitter follower changes abruptly from -0.85 to 05 and from -1.55 to -0.75. At the moment of applying a positive voltage drop to input b, transistor 1 opens, through it and resistor 8 current flows due to the accumulated charge of open diode 10. After discharge, diode 10 closes, the potential at the collectors of input transistors 1-3 and the emitter follower output drops respectively, up to the levels of -0.75 and -1.55, determined by the formulas

  ..e + D D

"VK - ,,

.,.

The duration of the positive pulse at the output of the circuit is determined by the resorption time of the charge accumulated in diode 10 through the open transistor 1 and resistor 8. In the case of supplying at least one of the inputs a and b of the inhibitory level -0.75, the circuit of transistors 2 and 3 conducts and when a positive differential is applied to the input, there is no pulse at the output of the circuit.

Subject invention

A logic element on the switches, the first of which contains n transistors, for example, a pn type with combined emitters and collectors, and the second current switch contains one transistor, for example, a pn type, in which the emitter is connected with transistors emitters first

a current switch and a base with a voltage reference, characterized in that, in order to expand the functionality of the element, a charge-accumulating diode is inserted in it, in which the anode is connected to the collectors of transistors of the first current switch, and from the transistors of the first current switch and the gate signal bus.

W

Output

-t

A

Output