SU1658319A1 - Transistor switch control device - Google Patents

Abstract

The invention relates to electrical engineering and can be used in power switching devices. The goal is to increase efficiency. The device contains an output transistor 1 and a control transistor 2, the bases of which are connected via a low-voltage source 3 and connected to the output of a current source 4 shunted by control key 5 of control unit 6. When control key 5 of control unit 6 is opened, transistor 2 opens and the output transistor 1. Due to the presence of a low-voltage source of voltage 3, the control transistor 2 operates at the saturation limit, which reduces the control losses of the control transistor 2 and reduces switching losses the output transistor 1. 4 g and f-ly, 5 Il. Ј (L

Description

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

The aim of the invention is to increase efficiency.

Fig I shows a functional diagram of the control device; in fig. 2-4 are practical embodiments of the control device; in fig. 5 - diagrams of currents and voltages on the elements of the device.

The transistor switch control unit contains an output transistor 1, a control transistor 2, a low voltage source 3, a current source 4 and a control key 5 of the control unit 6. The source current 4 can be made

the current transformer 7, the first 8 and the second 9 windings of which are connected between the emitter of the control transistor 2 and the second output terminal, and the control winding 10 are bridged by the control switch 5 of the control unit 6. The connection of the output transistor 1 base to the windings of the current transformer 7 made through an additional winding 11, and the control unit 6 consists of a two-phase pulse generator 12 and a thyristor 13 that shunts the control winding 10. A low-voltage source 3 can be made on two diodes 14, 15 shunted capacitor.

The device works as follows.

OE SP

00

with so

When the key 5 is open, the current from the current source 4 through the voltage source 3 enters the base of the control transistor 2. At the same time, the voltage on its collector decreases and is set at a level equal to the sum of the voltages of source 3 and the voltage drop at the base-emitter junction of the output transistor 1, providing the transistor 2 with a mode of low saturation. Transistor 1 is opened. The source current 4 is chosen so as to ensure the saturation of transistor 1. When the key 5 is closed, the base-emitter junction of transistor 2 is applied from Acceptable voltage of source 3 causing forced shutdown. At the same time, the collector current of transistor 1 begins to pass through the base region, causing a forced dissipation of charge from the base region and turning off transistor 1

In the practical scheme of the control device (see FIG. 2), the current source 4 is suitably performed on the current transformer 7, and the key 5 on the high frequency thyristor 13. In this case, the pulse converter can be controlled from the pulse generator 12, and the pulses for unlocking of the transistor 1 (see Fig. 5a) is supplied to the anode of the thyristor 13, and for locking (Fig. 56) to its control electrode. When a pulse arrives at the control electrode of the thyristor 13 (see Fig. 56), the voltage is opened on all windings of the transformer 7 r is reduced, which is equivalent to the closure of the key 5 in the circuit of FIG. 1 The transistor 2 closes and the current begins to pass through the collector circuit of transistor 1, its base, the second winding 9 of the transformer 7 Current flow through the second winding 9 of the transformer 7 causes the current to flow through it control winding 10 and open thyristor 13 As it is, the thyristor 13 reliably blocks the input circuits of transistors 2 and 1 from receiving interference during the entire time that the charge is removed from the base of transistor 1

In this case, the current through the output transistor 1 and the control winding 10 of the transfer of the mator 7 becomes zero, on all windings (see Fig. 5s, d) the voltage sign changes (blocking for transistors 1 and 2) and the energy accumulated in the core of the transformer 7 The demagnetization current flows through the thyristor 13, causing it to be forcedly closed, and through the output circuits of the pulse generator. After demagnetizing the core of the transformer 7, the device is flowing to the next opening pulse.

The diagrams illustrating the operation of the converter are shown in Fig. 5

(see fig. 5a) the opening of the transistors 2 and 1 is performed at time 2 /, due to the pulse on the control electrode of the thyristor 13 (see fig. 56), the thyristor 13 opens and the voltage on the winding decreases to zero (see fig. 5c) the transformer windings and the charge accumulated in the base of transistor 2, the base current of this transistor decreases linearly with a change in sign (see

FIG. LD) on the interval / 2- 3

At time t3, the base-emit transition of transistor 2 abruptly restores its reverse resistance, causing a drop (and a small negative surge) of the voltage on the winding 8 (see Fig. 5c). Transistor 2 turns off and the emitter of the transistor 1 turns off. to the base (see FIG. 5e). In the interval / s-1, charge is absorbed from the base-collector region of transistor 1,

0, the latter is turned off (see Fig. 5ac), and the voltage on its collector increases (see Fig. 5h)

five

0

five

On the / 4-is interval, reimagining occurs or, in this case, demagnetization of the current transformer 7. The diagram of this voltage depends on the circuits shunting the windings of the current transformer. If there are no such circuits (see Fig. 2 and 3), accumulated in the core of the current transformer, the voltage on the winding 8 (see Fig. 5d) changes sign (lock thyristor 13) and increases until the junction base of the emitter of the transistor 2 enters the avalanche breakdown state , energy stored in the core, ol NOSTA outputted transformer pa (magnesium chivaets - inverter is prepared for receipt of the next triggering of the pulse (see Figure 5a)

Polar connection of trans windings

0 of the formatter 7 (see Figs 2 and 3) must be such that when current flows through the load and the second winding 9 of the transformer 7 on its first winding 8, a voltage is formed (see Fig 5g) with polarity

From this point of view, the gs providing opening transistors 2 and 1 of the Circuit of FIGS. 2 and 3 are identical to the circuit of Fig. 4a and are equivalent to the widespread circuit of the magnetotransistor switch of Fig. 46 The separation of the windings, as shown in Figs. 2, 3, see Fig. 4a with the convenience of a specific implementation, the source voltage 3 is chosen so as to ensure reliable closing of the transistor 2 to reduce the collector-emitter voltage of transistor 2 (and, if necessary, to put it into a mode with greater depth of saturation) sequentially with the base of transistor 1 t be included additional winding 11 current transformer 7 It is advisable to

0

five

perform in the form of a tap from the first winding 8 of the transformer 7 (see Fig 3)

Thus, the proposed device normalizes the saturation depth of a low-voltage transistor due to non-linear feedback between the base and collector of this transistor. Moreover, in the proposed source the role of feedback elements is performed by switching the base-emitter of the high-voltage transistor and low-voltage source In addition, the use of a current transformer and thyristor as control elements made it possible to reduce the loss of control and loss at the time of switching the transistor key, which allowed it possible to improve efficiency of the device

Claims (1)

Invention Formula 1 A transistor switch control device containing an output transistor, the collector of which is connected to the first output terminal, and the emitter is connected to the collector of the control transistor, the emitter of which is connected to the second output terminal, a low-voltage source, a current source, the control switch of the unit pack This is characterized by the fact that in order to increase the efficiency, the base of the control transistor is connected via a low-voltage source to the base of the output transistor connected by a current source l yuschim key blo 0 control, with the emitter of the control transistor 2 The device according to claim 1, characterized in that the current source is made in the form of trans current format transformer, the control winding of which is shunted with the control key of the control unit, and the control transistor emitter is connected to the second output terminal through the first and second current transformer windings connected in series with the connection point of which is connected to the output transistor base 3 Device in PP 1 and 2, characterized in that the connection of the base of the output tran 5 resistors with the connection point of the first and second windings of the current transformer are made through the additional winding of the transfer of the mator 4 The device according to claims 1-3, characterized in that the low-voltage source is 0 neither is made in the form of two diodes connected in series according to and shucked by a capacitor 5 The device according to claims 1-4, characterized in that the control unit contains a TLD 5 phase pulse generator the first output terminal of which is connected to the control electrode of the thyristor of the shunt control winding of the current transformer, the first output of which is connected to the common output terminal of the generator 0 pulses, the second output of which is connected to the second output of the winding vn of the current transformer Fig about aZi to o Zi 2i D about b at g 7 R B / " well one n I 4