SU1157652A1 - Univibrator - Google Patents

Abstract

SINGLE VIBRATOR containing RS-trigger, single output of which is connected to the inverter input, 5 input is connected to the startup bus, zero output is connected to the output bus, the time setting the capacitor and resistor characterized in that in order to increase the stability of the duration of the output pulse when the temperature changes power supply voltage, the first and second pnp transistors, a voltage divider, a resistor and a diode, the anode of which is connected to the output of the inverter, are introduced into it, the cathode is connected to the base of the first pnp transistor, the collector of the secondpnp transistor and one lining the time of the driving capacitor, the second lining of which is connected to the common bus, the emitter of the first pnptransistor is connected to the R input of the RS flip-flop and through the resistor to the common bus, the collector of the first hpn transistor is connected to the power bus, the base of the second pnp transistor (Lra is connected to the midpoint of the voltage divider, which is connected between the power line and the common bus, the emitter of the second nppn transistor is connected to the common by bus. ate o) ate iss

Description

The invention relates to a pulse technique and can be used in various electronic devices.

The purpose of the invention is to increase the stability of the 5 duration of the output pulse when the temperature and voltage 'supply.

The drawing shows a single vibrator.

The one-shot contains RS-trig — 10 rep 1, the S-input of which is connected to the start bus 3, a single output with the input of the inverter 2, the output of which through the diode 11 is connected to the base of the first η-p-p-transistor 7, collector-15 rum the second pnp transistor 8 and a timing capacitor 5. The collector of the first pnp transistor 7 is connected to the power bus, an emitter with the R-input of the RS flip-flop 1 and through the resistor 10 with a common bus. The base of the second η‘-rtp transistor 8 is connected to the midpoint of the voltage divider 9, which is connected between the power bus and the common bus. The emitter of the second 25 rdp transistor 8 through time — the driving resistor 6 is connected to a common bus. The output bus 4 is connected to the zero output of the RS-trigger 1.

One-shot works as follows.

In the initial state, a high potential is present at the output of a single vibrator. RS trigger 1 is in the zero state.

At the output of inverter 2 there is a high potential. The capacitor 5 is charged to a voltage U _H , determined by the supply voltage E and the voltage drop at three directly biased pn junctions (taking into account the diode 11 included in the charging circuit of the capacitor 5)

U _H = E - 3U _np „45

At the moment of receipt of the control signal (low potential) at the input of the one-shot, the RS-trigger 1 goes into a single state. At the inverter output. 2, a low potential appears, the diode 11 is locked and the discharge of the capacitor 5 begins through the transistor 8 and the resistor 6 to the common bus. It starts at the same time. pulse formation at the output of ₅₅ single-shot. Discharge current) is equal to: ^ ba ~ ^ pr where - voltage based on transistor 8;

and _pr is the voltage drop at the forward-biased emitter-base transition of the transistor 8J R is the resistance value of the resistor 6.

When the voltage across the capacitor 5 drops to the value U _K = 3U _np (taking into account the voltage drop at the emitter-base junction of the transistor 7), the RS-flip-flop 1 goes into the zero state _Z and the pulse formation at the output of the single-shot ends. If at this moment there is a high potential at the input of the one-shot, a high potential appears at the output of the inverter 2, the diode 11 is unlocked, the capacitor 5 is charging. At the end of the charge of the capacitor 5, the device returns to its original state.

The pulse duration at the output of a single vibrator is

where C is the capacitance of the capacitor 5.

If the parameters of the resistive divider 9 are chosen so that Ug- = ---, the pulse duration at the output will be equal to

those. the pulse duration at the output of a single-shot does not depend either on the supply voltage or on the temperature of the voltage changes at directly biased p-ft junctions. By adjusting the divider 9, they achieve the most complete compensation for instability.

Compared with the well-known one-shot, the stability of the output signal increases by more than five times.

The application of the proposed invention in various electronic devices (duration modulators, time delay devices, etc.) will dramatically increase the stability of their work when the temperature changes .. without significantly complicating the device itself. I

Claims (1)

A SINGLE-VIBRATOR containing an RS-flip-flop, the single output of which is connected to the inverter input, the S-input is connected to the start bus, the zero output is connected to the output bus, the time-setting capacitor and resistor are characterized in that, in order to increase the stability of the output pulse duration at soybean timing resistor with common bus. changing the temperature and supply voltage, the first and second npn transistors, a voltage divider, a resistor and a diode are inserted into it, the anode of which is connected to the inverter output, the cathode is connected to the base of the first rpn transistor, and the collector of the second rpn η a transistor and one lining of a timing capacitor, the second lining of which is connected to a common bus, the emitter of the first η-p-n · transistor is connected to the R-input of the RS flip-flop and through the resistor to the common bus, the collector of the first hp-n transistor is connected to the power bus, base of the second pp-transistor with It is connected to the midpoint of the voltage divider, which is connected between the power bus and the common bus, the emitter of the second p — p — p — transistor through dinen