SU1525897A1 - Ac gate - Google Patents

Abstract

The invention relates to the field of pulsed technology and can be used for noiseless switching of a power load. The purpose of the invention is to increase the reliability of work. The alternating current key contains thyristors 1,2, diode bridge 6,7,8,9 bipolar and field-effect transistors 10,11, diode 12, resistors 13-16, optocoupler 17. Introduction of a constant voltage source and switching on between its poles 20,21 of the series circuit of the resistor 13, the photodiode of the optocoupler 17, the diode 12 and the resistor 14, as well as the connection of the resistor 14 into the diagonal of the DC bridge diodes 6,7,8,9 and the connection of the base of the transistor 10 to the pole 20 through serially connected the resistor 15 and the drain-source gap of the transistor 11, the gate and the source of which are connected to the terminals resistor 13, reduces the anode voltage at which each successive unlocking of the thyristors 1.2 and, accordingly, reduces the internal noise of the device in the on state and provides a more complete transfer of the network voltage to the load 3. Turning on the Zener diode 22 increases the reliability of unlocking the transistor 11. 1 c.p. f., 1 ill.

Description

cl

HS

cl

00

Yu

The invention relates to a pulse technique and can be used to switch a power load.

The purpose of the invention is to increase the reliability of operation by reducing the level of internal noise in the on state by unlocking the thyristors with a lower level of anode voltage.

The drawing shows a circuit diagram of the device.

101UCH of alternating current contains opposite-parallel connected thyristors 1 and 2 in the circuit of connecting the load 3 to the mains (terminals 4 and 5), a diode bridge in which the diodes 6 and 7 connected by anodes are connected by cathodes to the control electrodes of the thyristors 1 and 2 , and diodes 8 and 9, connected by cathodes, are connected by anodes to power terminals T1FISTORS 1 and 2, bipolar transistor 10, included in the diagonal of the bridge DC current on diodes 6-9, field-effect transistor 11, diode 12, resistors 13-16 and optocoupler 17, the LED of which is connected to the control buses 18 and 19

A DC voltage source is inserted into the device, between the first and second poles 20 and 21 of which a series circuit of resistor 13 is connected, the photodiode of the optron 17, diode 12 and resistor 14. At the same time, resistor 14 is connected to the diagonal of the direct current bridge on the diodes 6-9 o The base of the transistor 10 is connected to the pole 20 through a series-connected resistor 15 and a drain-source gap of the transistor 11, the gate and the source of which are connected to the terminals of the resistor 13, and the diode 12 is connected in the forward direction with respect to the voltage between the poles 20 and 21 and sun RIVER with respect to the photodiode of optocoupler 17. The drain of the transistor circuit 11 can be turned about the zener 22

The device works as follows

When the optocoupler 17 is de-energized, the voltage from the pole 20 through the resistor 13 is applied to the gate of the transistor 11 and reliably closes it. Since a small leakage current source - the drain of the transistor 11 is discharged through the resistor 16, the transistor 10

it also turns out to be in a closed state and the grid voltage is applied to it, to the collector - positive potential through diode 8 or 9, and to the emitter - negative through the control electrode of the thyristor 2 and diode 7 or the control electrode of the thyristor 1 and diode 6. Pulsating voltage

Q on the transistor 10 creates a small current through the resistor 14, but this current does not affect the state of thyristors 1 and 2.

When tires 18 and 19 are served

 the voltage, the photodiode of the optocoupler 17 goes into the conducting state. However, if there is a positive potential on the collector of the transistor 10, the diode 12 is locked and there are no changes

Q in the operation of the device does not arrive until the collector potential of the transistor 10 becomes less than the potential of the pole 20. At the same time, the diode 12 opens slightly and through it

5 and the resistor 14 begins to pass a current reducing the potential of the gate of the transistor 11. As the voltage across the transistor 10 further decreases, unlocking the diode 12 leads to a further decrease in the gate potential and unlocking the transistor 11. Through the circuit: pole 20, the source is the drain of transistor 11, the resistor 15, the base-emitter transition of the transistor 10 flows the current introducing the transistor 10 into the saturation mode, because the collector voltage and, accordingly, the collector current are small.

0

five

Subsequent increase in voltage

the network leads to the rise of the rising collector current of the transistor 10 practically without increasing its output voltage. Therefore, the diode 12 is not locked and the transistor 11 continues to provide the base current for the transistor 10. The collector current of the transistor 10 opens the thyristors 1 and 2.

After that, the collector current of the transistor 10 stops and it jjfi in a saturated state, which provides a corresponding decrease in the anode voltage, at which the next unlocking of the thyristors 1 and 2 occurs. As a result, a slight internal

the noise of the device is in the on state and the network voltage is transferred to the load 3 more completely.

Claims (2)

1. AC key containing anti-parallel connected thyristors in the load connection circuit to the mains, a diode bridge in which the diodes connected by anodes are connected by cathodes to the control electrodes of the thyristors, and the diodes connected by cathodes are connected by anodes to the power terminals of the thyristors , the reliability is increasing, a constant voltage source is introduced, between the first and second poles of which a series circuit is connected from the first resistor, photodiode of the optocoupler, diode and second resistor, while the second resistor is connected to the diagonal of the direct current of the diode bridge, the base of the bipolar transistor is connected to the first pole of the constant voltage source through the third resistor connected in series and the drain-source gap of the field-effect transistor, the gate and source of which are connected to the terminals of the first resistor and the diode is on in the forward direction with respect to a constant voltage source and polarity transistor included in the di- 20 counter to the photodiode DC agal diode bridge, field effect transistor, diode, resistors, and an optocoupler, the LED of which is connected to the control buses, characterized in that Editor I. Casarda Tehred L. Oliynyk Order 7242/54 Circulation 884 Subscription VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production and publishing plant Patent, Uzhgorod, st. Gagarin, 101 optocoupler. 2. The key according to claim 1, distinguishing d in that a litron is included in the field-effect transistor. Proofreader V. Kabatsiy