SU632058A1 - One-shot multivibrator - Google Patents

Description

one

The invention relates to a pulse technique and can be used in various devices for discrete information processing.

A one-shot is known, containing a RS-trigger, performed on two-input AND-NOT valves, the single output of which is connected to its R-input via a series-connected diode, an inverter covered by negative feedback, and the time specifying the RC circuit 1.

However, the reliability of such a device is low as a result of the fact that the transistors of an inverter connected through a diode to a single output of an RS flip-flop work in an unnatural linear mode, resulting in an excess of the permissible power dissipation on the valve elements.

The aim of the invention is to increase the stability of the duration of the pulses being formed, which is achieved by introducing a differentiating RC circuit and an optocoupler-inverter switch, the anode of the LED of which is connected via an accumulator capacitor, to the one-shot containing the RS trigger, the inverter and the storage capacitor.

the power supply bus and directly to the output of the inverter, the inputs of which are connected to the zero output of the RS flip-flop, the single output of which is connected via a differentiating RC-circuit to the cathode of the LED of the switching opto-optical inverter, the output of which is connected to the zero input of the RS-flip-flop.

Functional diagram of the device shown in the drawing.

A single-vibration, made on elements of transistor-transistor logic, contains RS-flip-flop on two-way AND gate valves - HE 1, 2, covered by cross-links. The zero input of the RS flip-flop is connected to the output of the opto-optical inverter-switch 3, the zero output is with the anode of LED 4 of the inverter-switch via inverter 5, parallel to the output of which is connected a storage capacitor 6, a single output is connected with the cathode of LED 4 through a differentiating RC circuit 7, consisting of a capacitor 8 and a resistor 9.

The single vibrator works as follows.

In the initial state, the signal 13 INPUT S RS-TpHrrej) fi iodasts a positive voltage. When eg (-m on the single and zero outputs of the trigger, low and high potentials act accordingly. Under the high level of the voltage on the zero output of the trigger, the output transistor of the inverter 5 is saturated and the capacitor 6 is discharged. Due to the low voltage level on a single trigger output.

Thus, equally low voltage levels act on the anode and cathode of the LED 4, as a result of which the LED 4 is closed, which corresponds to a high voltage level at the output of the inverter switch 3.

When entering on. the signal input of the RS flip-flop of a negative impulse, the latter goes into a state of quasistable equilibrium, characterized by a high level of voltage at a single and a low level at the zero output of a trigger. The output transistor of the inverter 5 closes abruptly, the capacitor 6 starts charging along the circuit: power source, -E,;, matching the collector circuit of the output transistor of the inverter 5, capacitor 6, common bus. The voltage at the anode of the LED 4 increases exponentially /

and .. En (), (I)

where constant is the time of charge.

The positive voltage drop from the single output of the trigger is released on the resistor 9. As the capacitor 8 is charged, the voltage on the cathode of the LED 4 decreases in the form of the exponent

U; (2)

where r is the time constant of the charge circuit of the capacitor 8.

The condition for driving the inverter switch 3 is that the voltage on the anode of the LED is exceeded relative to the voltage on the cathode by a certain amount U ,, UK. At the same time, the LED jumps to the conducting state (the radiation state) in steps. As a result, a negative pulse "end of formation" is formed at the output of the inverter switch 3, which returns the RS flip-flop to the initial LUcroHHne. At this point, the formation cycle of the set duration ends. In this case, the capacitors 6 and 8 are discharged through the saturated output transistors 5 of the valves.

When the next negative negative pulse arrives at the trhigger signal input, the cycle of the one-shot operation is repeated.

From expressions (1) and (2) it follows that Q provided g ". g g the duration of the pulse formed by the one-shot corresponds to the expression

 s1p2. (h;

From expression (3) it follows that the duration of a pulse generated by a single vibrator does not depend on the magnitude of the voltage of the power source, and its stability is determined mainly by the stability of the parameters of the capacitor charge circuits and in the nervous approximation does not depend on the operating mode of the LED.

The proposed one-vibrator allows to form not only a pulse of a given duration, but also an auxiliary pulse “end of formation, which expands its functionality. five

Claims (1)

Invention Formula A single vibrator containing an RS flip-flop, an inverter and a storage capacitor, characterized in that, in order to increase the stability of the duration of the generated pulses, a differentiating RC circuit and an opto-switch invertor are inserted, the anode of the LED of which is connected to the power supply bus and directly - with the inverter output, input | 1 of which is connected to the zero output of the RS flip-flop, the single output of which is a chorech differentiating RC-circuit connected to a; diode optocoupler inertora-switch. : l, the output of which is connected to the zero slip of the RS flip-flop. Sources of information taken into account in the examination: 5 1. USSR Copyright Certificate No. 539367, cl. H 03 K 3/284, 1975. entrance Output : end of ramming