SU1665473A1 - Device for control over transistor key - Google Patents

Abstract

The invention relates to the field of electrical engineering and can be used in power switching devices. The goal is to increase reliability by reducing the switching time of the output transistor. The device contains an output transistor 1 connected through the first 2 and fifth 10 resistors, shunted by the first capacitor 11, to the third 5 and fourth 6 transistors, when switched, which is forced unlocking and locking of the output transistor 1, due to the flow of the accelerating current unlocked and locked through the first capacitor 11 of small capacity. Maintaining the blocking voltage at the base-emitter junction of the output transistor 1 is provided by the second capacitor 12 of large capacity. 2 Il.

Description

VI

WITH

The invention relates to the field of electrical engineering and can be used in power switching devices of radio engineering, automation and computer systems.

The aim of the invention is to increase the reliability of a transistor switch by reducing the switching time of the output transistor.

Figure 1 shows the electrical circuit of the device proposed; 2 shows current and voltage diagrams for device elements.

The control device of the transistor switch contains the output transistor 1, the first resistor 2, the first 3 and second 4 input transistors, the third 5 and fourth 6 transistors, the second 7, the third 8, the fourth 9 and the fifth 10 resistors, as well as the first 11 and second 12 capacitors .

As the first and second input transistors 4 and 3, open collector logic inverters or transistor optocouplers can be used.

The device works as follows.

When the trigger signal is applied to the control input of the transistor switch, the input transistors 3 and 4 are unlocked. In this case, the first input transistor 3 shunts the base-emitter junction of the fourth transistor 6, which is locked, and the third transistor, under the action of the current flowing through the third resistor 8, goes into an open saturated state. At the same time, a current pulse 13 (figure 2) flows through transistor 5, capacitor 11 and base-emitter junction of output transistor 1 (FIG. 2), and the current necessary to keep output transistor 1 in saturated state flows through resistors 2 and 10 state, taking into account the value of the output switched current. When the blocking signal arrives at the control input of the transistor switch, transistor 5 closes and transistor b goes into an open saturated state. In this case, the base of the output transistor 1 receives a blocking voltage 14

(Fig. 2), through capacitor 11, which causes forced shutdown of the output transistor, and the voltage on the capacitor 12, of large capacity, ensures the presence of a constant negative voltage at the base-emitter junction of the output transistor 1, which keeps it in the closed state.

So the presence of the first 11 and

The second capacitor 12 facilitates the forced unlocking and locking of the output transistor and shortens its switching time.

Claims (1)

Invention Formula A transistor switch control unit containing an output transistor whose collector and emitter are connected to the output pins, and the base is connected to the first output of the first resistor, the first and second input transistors whose bases are connected to the control input, the emitters are connected to the first input output, the collector of the first the input transistor is connected through the second resistor to the second input terminal, and the collector of the second input transistor is connected through the third resistor to the base of the third transistor, the conductivity of which opposite the conductivity of the input transistors, the emitter of which is connected to the second input terminal, and the base-emitter junction is shunted by the fourth resistor, the fourth transistor, the emitter of which is connected to the first input the output, the fifth resistor, the first and second capacitors, characterized in that, in order to increase reliability, by shortening the switching time of the output transistor, the base of the fourth the transistor is connected to the collector of the first input transistor, and the collector to the collector of the third transistor and through the first capacitor to the output transistor base, the fifth resistor shunted by the second capacitor connected between the second output of the first resistor and the connection point of the collectors of the third and fourth transistors, and the emitter of the output transistor is connected to one of the input pins. FIG. 2