RU1812631C - Transistor switch - Google Patents

Abstract

Usage: the invention relates to a pulse technique and can be used in power supplies and high voltage switches. The inventive device comprises: 3 transistors (1,2, 19), 3 capacitors (12, 13, 14), current limiter (8), 3 diodes (9,10,11), 4 resistors

Description

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The invention relates to pulse technology and can be used in power supplies and high voltage switches.

The purpose of the invention is to increase the reliability of a transistor switch.

Compared with the known transistor switch, two capacitors, four resistors, two diodes, and a transistor are introduced. The use of newly introduced elements has no features compared with use in known devices. The combination of connections of the second, third diodes, the first, second, third, fourth resistors, the second capacitor, the third transistor allows you to adjust the delay in opening the power transistors depending on the current flowing in the output bus at the time of closing the power transistors in the previous cycle. The introduction of a third control bus and a third capacitor allows further control of the opening delay. In addition, this set of connections allows limiting the base current of the second power transistor when it is closed at a safe level. This increases the reliability of the key.

The drawing shows a diagram of a transistor switch.

The transistor switch contains the first 1 and second 2 power transistors, the first 3, second 4, third 5 control buses, output bus 6, common bus 7, current limiter 8, first 9, second 10, third 11 diodes, first 12, second 13, the third 14 capacitors, the first 15, the second 16, the third 17, the fourth 18 resistors, the third transistor 19. The current limiter 8 can be performed both on the resistor and in the form of a current stabilizer,

The emitter, collector of the first power transistor 1 are connected respectively to a common bus 7, the emitter of the second power transistor 2, the base of the second power transistor 2 is connected respectively through the first diode 9 to the second control bus A and through the current limiter 8 to the first output of the first capacitor 12, and its collector is connected to the output bus 6. The first output of the first capacitor 12 is connected through the third capacitor 14 to the third control bus 5 and through the second resistor 16 connected in parallel with the second capacitor 13 to the collector the third transistor 19. The emitter of the third transistor 19 is connected to a common bus 7, the base through the fourth resistor 18 with the first unit. bus 3, the second input of the first capacitor 12 is connected to the anode of the second

diode 10, the cathode of the third diode T1 and through the first resistor 15 with a common bus 7. The cathode of the second diode 10 is connected to a common bus 7, the anode of the third diode 11 is connected to the base

the first power transistor 1 and through the third resistor 17 with the first control bus 3.

The transistor switch operates as follows.

0 An external positive bias source is connected to the second control bus 4.

Let the voltage proportional to voltage to the collector of the second power transistor 2 be applied to the third control bus 5. When a closing current is applied to the first control bus 3, the first power transistor 1 and the third transistor 19 are closed.

0 the open circuit mode of the emitter of the second power transistor 2 and the current of the output bus 6 begins to flow through the collector-base junction of the second power transistor 2, current limiter 8, the first capacitor

5 12, a second diode 10 and a first resistor 15 to a common bus. In this case, the voltage at the first capacitor 12 increases in proportion to the output current. bus 6. Current limiter 8 sets the safe base current level of the second power transistor 2. After the absorption of the charge in the base, the second power transistor 2 starts to close, while on the other. the voltage on its collector begins to increase5, hence the voltage on the third control bus 5 also increases. The first capacitor 12 is additionally charged through the circuit; a third control bus 5, a third capacitor 14, a first capacitor 12, a second diode 10, and a first resistor 15.

Thus, the voltage at the first capacitor 12 is proportional to the current of the output bus b and the voltage at the collector

5 of the second power transistor 2. Until the opening current is applied to the control bus 3, the charge on the first capacitor 12 is stored. When an opening current is applied to the first control bus 3, it opens

0 third transistor 19, In this case, the discharge of the first capacitor 12 to the second capacitor 13 starts along the circuit: the first output of the first capacitor 12, the second capacitor 13, the collector-emitter junction of the third

5 of the transistor 19, the first resistor 15, the second terminal of the first capacitor 12. The voltage drop that occurs on the first resistor 15 leads to the opening of the third diode 11. In this case, the base-emitter junction of the first power transistor 1

It turns out to be a shunted diode 11, so it does not open. As the first capacitor 12 discharges, the voltage drop across the first resistor 15 decreases, which leads to the closing of the third diode 11. From this moment, the first power transistor 1 opens. The delay time from supplying the opening current to the first control bus 3 before opening the first power transistor 1 in proportion to the current in the output bus 6 and the collector-emitter voltage of the transistor 1 in the previous cycle. After opening the first power transistor 1, an opening current begins to flow through the circuit: the second control bus 4, the first diode 9, the base-emitter junction of the second power transistor 2, the collector-emitter junction of the first power transistor 1, common bus 7. The first 12, the second 13, the capacitors are discharged through the second power transistor 2, and contribute to its forced opening.

Further, all processes are repeated.

Improving reliability is achieved by decreasing the open state of the switch by increasing the turn-on delay of the first power transistor 1 with increasing current in the output bus b and the collector-emitter voltage of the second power transistor 2, as well as by limiting the base current of the second power transistor to a safe level 2 at the stage of closing it. In addition, the efficiency of the key is improved by using energy on the capacitors to open the second power transistor 2. A further increase in reliability is possible by applying a voltage proportional to the voltage of the input power supply to the third control bus 5.

Claims (1)

SUMMARY OF THE INVENTION A transistor switch containing a first power transistor whose emitter is connected to a common bus, a second power transistor whose collector is connected to an output bus, an emitter to a collector of a first power transistor, and a base through a first diode connected to a second control bus and through a current limiter - with the first output of the first capacitor, which means that, in order to increase reliability, the second, third capacitors, the third transistor, the first, second, third, fourth resistors, the second, third diodes, a third control bus, and the first output of the first capacitor through the third capacitor is connected to the third control bus and through the second resistor and capacitor connected in parallel, connected to the collector of the third transistor, the emitter of which is connected to the common bus, the base through the fourth resistor is with the first control bus, the second terminal of the first capacitor is connected to the anode and cathode of the second and third diodes, respectively, and through the first resistor to the common bus, the cathode of the second diode is connected to the common otherwise, the anode of the third diode is connected to the base of the first power transistor and che Res third resistor - to the first control bus.