SU1192118A1 - One-shot multivibrator - Google Patents

Abstract

ONE BRLTOR, containing a capacitor and a current-setting resistor, a thyristor, a current amplifier with inverting and non-inverting inputs, the first plate of the capacitor connected to the cathode of the thyristor, the input of the single-oscillator is the control electrode of the thyristor, which is distinct from and with the same vibrator. reliability and efficiency, additionally introduced a bipolar transistor, a charging resistor and a switch, with the base of the bipolar transistor connected to the power bus, the emitter through the current-setting resistor-with a common fluid, and the collector the second capacitor plate, the inverting input of the current amplifier is connected to the thyristor anode, the non-inverting input to the power bus, the first capacitor plate is connected to the common g bus through a serially connected switch and charging resistor, and (L control input of the switch to the output of the inverting current amplifier.

Description

1P

The invention relates to a pulse technique and automation, and to a thyristor device to cpopMHpoiJani electric impulses of a given duration, including devices for pulse-width control of electrical devices,

The purpose of the invention is to increase the reliability of the device while simultaneously simplifying the circuit and increasing the convenience of tuning by eliminating the dependence of the moment of locking the circuits 1 on the magnitude of the holding current of the applied thyristor, as well as improving the efficiency of the circuit due to the smart current consumption in the pause,

The drawing shows a schematic diagram of a single uvibrator.

The single-oscillator contains the time specifying the current source on the bipolar transistor 1, connected according to the OT scheme, its base being connected to the power supply bus, and the collector to the first capacitor face 2 of the reference peep time, the second face of the condator 2

but closed, the 1st switch 3 and the charging circuit resistor 4 with a common bus and, in addition, connected via a source of start-up pulses 5 to the control electrode of the thyristor 6, which is the input of the whole one-vibrator, the thyristor 6 connected by a cathode to the second capacitor plate 2, and the anode with the input of the current amplifier 7 at the bipolar transistor, the emitter of which is connected to the common bus, the inverting output of the current amplifier is the collector of this bipolar transistor and connected to the control input of the key 3 and at the same time the output of the one-vibrator, time defining a current source includes voltage driving resistor 8 which connects the emitter of bipolar transistor 1 schinoy general, as well as a current source 9, a remote control pulse length, connected in parallel with the base-emitter junction of bipolar transistor 1.

The single vibrator works as follows.

In the initial state, the capacitor 2 is charged up to the supply voltage through the biaxial collector of the bipolar transistor 1, the normally closed switch 3 and the charged resistor 4, and the thyristor 6 locked through a directly shifted junction.

When a pulse from a source of starting pulses 5 is applied to the input of the one-shot, the thyristor 6 is unlocked, the capacitor 2 is discharged in the circuit: the collector-base junction of the bipolar transistor 1 shifted in the opposite direction, the input resistance of the inverting current amplifier 7, the thyristor 6. At the same time the output of the current amplifier 7 is formed, the output pulse, the key 3 size 1, 1 kaet. Since the collector-base transition of the bipolar transistor 1 is biased in the opposite direction, this transistor enters the active mode of the current repeater through the current set resistor 8. When an additional current source 9 is connected, the current through the collector base of transistor 1, which is the discharge current of the capacitor 2, equal to the sum of the currents from this source and resistor 8. The use of current source 9 provides remote control of the exposure time of the one-shot. When capacitor 2 is discharged, the voltage across it decreases linearly due to the discharge current being stabilized by transistor 1. When the capacitor is completely discharged, bipolar transistor 1 enters a cut-off mode, the discharge current falls below the holding current of the thyristor 6, and the latter is reliably locked, resulting in to the locking of the current amplifier 7, to the closure of the key 3 n to return the one-shot to the initial state. The duration of the exposure of an impulse pulse t of a single vibrator - Taking into account the linearity of the change in voltage on the capacitor 2, is defined as

V - pit i - resolution,

Where

- supply voltage;

Pete

Srdir - the total current from the current-carrying resistor 8 and the current source 9;

C is the capacitance of capacitor 2. In order to ensure reliable connection of the one-shot to the resistance of the current-carrying resistor 8, a limitation is imposed

,,, / J

Aerm. "Ks

where the maxc is the maximum holding current of the thyristor 6. To ensure reliable shutdown of the one-shot, the condition is .K.A / -oder - w-MH where Ilcpa. ON. switch current 3; current amplifier gain factor .7; the minimum current is required for the thyristor 6. The circuit does not contain reference voltage sources and, if the specified conditions are met, the single-oscillator practically does not need to be tuned, while guaranteeing operability, which ensures an increase in reliability. In addition, the one-shot has an increased resistance to changes in supply voltage, since an increase in MPAC is simultaneously accompanied by a proportional increase in the discharge and does not lead to a change in the exposure time t, 84 In addition, the single-shot has an increased temperature stability, since the leakage current of the capacitor 2 passes through the same thyristor 6, as the discharge current, and the increase in leakage current with increasing temperature, causing a decrease in the duration tj ,, is compensated by an increase in t, due to a decrease in „„ „ and a later lock-in of the thyristor 6. The cost effectiveness of the one-shot increases a-a by excluding sources of reference voltage. When operating in the high-frequency domain, key 3 can be performed, for example, on a field or bipolar transistor. When operating in the low-frequency region, key 3 can be performed on a relay, and the inertia of the relay in the release process increases the reliability of the one-shot deactivation, thereby be removed then the restriction of 3 tpaS to

Claims (1)

(57 / SINGLE VIBRATOR, comprising a capacitor and a current-sensing resistor, a thyristor, a current amplifier with inverting and non-inverting inputs, the first capacitor plate being connected to the thyristor cathode, the input of a single-vibrator is a thyristor control electrode, characterized in that, in order to increase reliability and economy, a bipolar transistor, a charging resistor and a key are introduced, the base of the bipolar transistor connected to the power bus, the emitter through a current-setting resistor with a common pin, and the collector with a second LadKom capacitor, an inverting input of the current amplifier is connected to the anode of the thyristor, the non-inverting input - with the power bus, the first plate of the capacitor connected to the common shinoy'cherez series connected switch and a charging resistor, and the control input of the switch - to yield an inverting current amplifier.