SU1487170A2 - Switch - Google Patents

Description

The invention relates to a pulse technique. The purpose of the invention is to increase reliability. The switch contains a LED 1, optically connected to photo2

diode 2, transistors 3 and 4 l-p-l-type, transistors 5 and 6 p-l-p-type, zener diode 9, diodes 7 and 8, resistors 10 ... 15 and power supply 20. The introduction of a phototransistor optocoupler 17 with a LED 18 and a phototransistor 19 ensures that the switch automatically returns to normal operation after the overcurrent or pulse interference is removed. The effectiveness of the switch is manifested in its use in two-phase and multi-phase inverters, as the load of which motors are used. 1 il.

1487170

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The invention relates to a pulse technique, can be used in inverters, pulse regulators, key voltage and current converters, and is an improvement of the invention according to the authors. St. No. 1264329.

The purpose of the invention is to improve the reliability of operation by ensuring the automatic return of the device to normal operation after removal of overcurrent or impulse noise.

The drawing shows the electrical circuit of the switch.

The switch contains the first LED 1, optically connected to the photodiode 2, the first 3 and the second 4 transistors I-p-l-type, the third 5 and the fourth 6 transistors p-l-p-type, the first 7 and second 8 diodes, Zener diode 9, the first 10, second 11, third 12, fourth 13, fifth 14 and sixth 15 resistors, capacitor 16 phototransistor optocoupler 17 with LED · 18 and phototransistor 19. The anode of photodiode 2 is connected to the base of transistor 3, the cathode to the collector of transistor 6, transistor emitter 3 is connected to the anode of the Zener diode 9 and the first output of the capacitor 16, as well as through resistor p 14 - with the base of transistor 4 and through a resistor 13 - with the emitter of transistor 4, the emitter of transistor 4 is connected via resistor 11 to the negative bus of power supply 20, the base of transistor 4 is connected through resistor 15 to collector of transistor 5 and anode of diode 8, the cathode of which is connected with the cathode of the Zener diode 9 and the base of the transistor 6, the emitters of the transistors 5 and 6 are connected to the second terminal of the capacitor 16 and through the resistor 10 are connected to the cathode of the diode 7, the anode of which is connected to the collector of the transistor 3 and the positive bus of the power supply 20. The LED 18 and the LED 1 are connected in series and connected to the control signal source terminals 21 and 22, and the phototransistor 19 is connected between the base of the transistor 5 and the resistor 12, the collector to the base of the transistor 5, and the emitter through the resistor 12 to the collector of transistor 4.

The device works as follows.

Transistors 4 and 5, phototransistor 19, resistors 12, 14, 15 and resistor 13, which serves as a current sensor, work in combination as a trigger. If the output current of transistor 3 does not exceed the set value, the voltage signal on the current sensor is not sufficient to trigger the trigger and transistors 4 and 5 are turned off and have no effect on the operation of transistor 3. When overcurrent, the voltage signal on the current sensor opens transistor 4, and since the phototransistor 19 is open (the phototransistor 19 opens simultaneously with the photodiode 2, i.e. when the unlocking level comes for the power

four

transistor 3), opens from, and transistor 5, the collector potential of which increases dramatically and the circuit with diode 8 turns off the transistor 6, thereby opening the circuit with photodiode 2 and locking the transistor 3.

In a known switch, in order to reset the protection trigger, i.e., return the electronic key to normal operating mode, it is necessary to disconnect the power supply 20 so that the capacitor 16 is discharged and the protection trigger is reset, and then turned on again. In the proposed electronic key, the key returns to the normal operating mode, after the overload current or interference is terminated, automatically, i.e. the arrival of the control signal to the low level terminals 21 and 22 keeps the transistor 3 in the closed state and at the same time closes the phototransistor 19, thereby opening the collector circuit of transistor 4 and dropping the protection trigger.

With the next clock cycle, when a control signal arrives at high level pins 21 and 22, phototransistor 19 opens, and if overcurrent or interference is still present, the protection trigger is again triggered and transistor 3 closes, but if there is no overload, the electronic key continues operate in normal operation, since the protection trigger is reset and does not have any effect on the operation of the power transistor 3.

Thus, this device, in comparison with the known, not only quickly and reliably protects the power transistor from a transition to a normal active mode and overcurrent, but also allows the switch to automatically return to a normal operating mode after the overcurrent or impulse noise is removed.

The effectiveness of this switch is particularly evident in its application in two-phase and more inverters, which use motors as a load, where starting and braking current surges are frequent, and trigger protection (for example, only in one of the phases) without the switch returning to the operational state leads to a "break" phase, which corresponds to emergency mode, as well as in devices with an automatic duty cycle, where stopping the duty cycle is extremely undesirable. In addition, the scheme of the proposed switch allows you to get rid of filters that suppress single impulse noise on the control circuit of the key.

Claims (1)

Claim Switch auth. St. No. 1264329, characterized in that, with the aim of increasing by 1487170 6 During operation, a phototransistor optocoupler is inserted, the LED of which and the photodiode optocoupler LED are connected in series and connected to the control signal source terminals, the phototransistor collector is connected to the base of the third transistor, and the third resistor is connected to the collector of the second transistor.