SU1221712A2 - One-shot multivibrator - Google Patents

Abstract

The invention relates to a pulse technique, is an improvement of the device according to the author. No. 892665 and can be used in electronic equipment as a delay generator and pulse duration. The purpose of the invention is to increase the reliability of the launch of a single-vibrator while expanding the range of permissible values of the duration of the trigger pulses. The single-oscillator contains the first logic element SLE) NAND 1, the output of which is connected to the input of the inverter 2 and through time the supply capacitor 3 is connected to the base of the transistor 4 and to the resistor 5 which is connected to the common bus with a different output. The emitter of transistor 4 is connected to the cathode of diode 6, the anode of which is connected to a power source. The collector of this transistor is connected through a resistor 7 to the output of the inverter 2, which is the output of the one-shot, and is connected via a feedback circuit to one of the inputs of the first LE, the other input of which is. connected to the output of the second LE of the NE-NE 8. One input of this LE is connected to the first installation input of the trigger 9 and to the launch bus of the oscillator. The other input of the second LE AND-HE 8 is connected to the output of trigger 9, second. S g ko l

Description

A swarm whose setup input is a switch to the collector of transistor 4. A single-oscillator can also operate with an input signal of negative polarity. At the same time, it was launched 1

The invention relates to a pulse technique and can be used in electronic equipment as a delay generator and pulse duration, is an improvement of the device, according to the author. No. 892665.

The purpose of the invention is to increase the trigger status of a single vibrator with an extended range of allowable values for the duration of the trigger pulses.

Figure 1 shows the circuit diagram of a single vibrator; figure 2 - timing charts of the one-shot.

The operation of the one-shot is explained for two cases (Fig. 2): the duration of the trigger pulse () is less than the duration of the output signal (t);

t o-h tu.

The one-vibration contains the first logical element AND-NOT 1, the output of which is connected to the input of the inverter 2 and through time specifies the capacitor 3. connected to the base of the transistor 4 and to the resistor 5, which is connected to a common bus by another output. The emitter of transistor 4 is connected to the cathode of diode 6 whose anode is connected to a power source. The collector of transistor 4 through a resistor 7 is connected to the output of inverter 2, which is the output of a one-shot and a feedback circuit, connected to one of the inputs of the first AND-1 logic element, the other input of which is connected to the output of the second logical element AND-NOT 8, one input of which is connected to the first setup input of the trigger 9 and with the start-up margin of the single-inverter, and the other input of the second AND-NE logic element 8 is connected to the output of the trigger 9, the second setup input of which is connected to the collector of transistor 4.

is given at a given front of the signal. However, for such a use of the vibrator, it is necessary to ensure that the trigger is set to O when the power of the one-shot is switched on. Id 2

The device works as follows.

In the initial state of the transistor 4 is open and the pattern is over. At the outputs of the logical element AND-NOT 8 and inverter 2 there are levels of logic 1 (AND), and at the output of logical element AND-NOT 1 - the level of logical O (and) .- The presence of logical 1 at

The output of the NAND gate 8 (Fig. 2b) and the output of the trigger 9 (Fig. 2e) is due in the initial state to a logical O input signal and on the one-shot trigger bus.

The time setting capacitor 3 charges to voltage

E, -

where E, is the voltage of the single-source power supply;

and - voltage drop across diode 6;

 - voltage drop at the forward shifted “S –a-junction. transistor 4.

When starting the circuit, a positive pulse (Fig. 2a) goes to the first installation input of the trigger 9 and to. the input of the logical element IS-NOT 8, as a result of which the output of the latter (Fig. 2b) forms a negative signal front (logical O), and the output voltage of the logic element 1 rises to the level AND logical 1.

A positive voltage drop AND -I is transmitted through capacitor 3 to the base of transistor 4 and locks it. The signal of logic 1 from the output of logic element 1 is inverted by inverter 2, which forms the negative pulse of the output signal of the one-oscillator. The leading edge of the negative signal from the output of the inverter 2 is transmitted through a resistor 7 to

3 the collector of transistor 4, to the first input of the logic element 1 and to the second setup input of the trigger 9. At the time when the signal on the collector of transistor 4 is generated

logical O, the feedback is closed and the circuit goes into a quasistable state of forming the duration of the output pulse t due to the discharge of the capacitor 3 with a constant time (Fig. 2d) - CcK5. In addition, this logical signal sets through time t 1. the output of the trigger to the zero state, which, in turn, switches the logic element 8 to the state of logical 1 in time tj and thereby forms a falling edge at the output of the logic element 8 (Fig. 2b). The pulse duration at the output of the logic element 8 of the pulse is determined by the sum of

+ t

39

+ t

3i

 the propagation time of the signal through the logic element 1 and the inverter 2;

tj-z, is the formation time of the logical O at the collector of transistor 4 with respect to the output of the one-oscillator plus the switching time of the trigger;

 - the switching time of the logical element AND-NOT 8 logical O to logical 1,

The proposed single-VTR can also operate with an input signal of negative polarity, while its triggering is performed at the back t edge of the signal (positive differential ..

However, for such use of the one-shot it is necessary to ensure that the O-trigger is set when the power of the one-shot is turned on,

Claims (1)

Invention Formula One-Vibrator, auth.St. 892665, characterized in that, in order to increase the reliability of launching a one-shot with an extended range of permissible values of the start-up pulse duration, a trigger and a second lot NOT element are entered into it, one input of which is connected to the trigger output, the other input is connected to one of the trigger inputs and one-shot trigger bus; another trigger trigger input is connected to the collector of the transistor; the output of the second NAND gate is connected to the input of the first NAND gate.