SU1193762A1 - Device for controlling power transistor - Google Patents

Abstract

A DEVICE FOR CONTROL OF A POWER TRANSISTOR, containing the supply and control transformers, the secondary inputs of the secondary windings of which are connected respectively to the first and second output terminals, the primary windings are connected to two. sources of rectangular stresses; phase-shifted on adjustable angle, two pairs of transistors, with each pair the collector of the first transistor connected to the second emitter, and the first emitter - with the second collector and the second output terminal, the base of each pair of transistors through resistors connected to the corresponding extreme output of the secondary winding transformer, it is believed that, in order to increase the efficiency, two additional resistors and two positive feedback windings control the transformer, and an additional nye resistors are connected one to the extreme pin terminals of the secondary windings 5 Matora supply transformer and the other terminal through the respective windings of positive feedback control transformatrra to the combined collector 1 and emitter of the corresponding pair of tran- ican. about 00 about 1C

Description

The invention relates to electrostatic and can be used in pulse stabilizers, pulse-width converters, inverters, as a device for controlling a power transistor switch.

The aim of the invention is to increase the efficiency

The drawing shows a circuit diagram of the proposed device.

The device contains a power transformer 1, the average output of the secondary winding of which is connected to the output terminal 2, the control transformer 3, the middle output of the secondary winding of which is connected to the second output terminal 4, two pairs of transistors 5.6 and 7.8, and 5 and 7 are connected to the collectors of transistors 6 and 8, respectively, and the collectors of transistors 5 and 6 are connected to the emitters of transistors 6 and 8 and to the second output terminal 5, the base resistor 9, connecting the bases of each pair of transistors 5.6 and 7, 8 with the corresponding by their extreme leads of the secondary winding of the control transformer 3, two ballast resistors 10 connected between the outer leads of the secondary winding of the power transformer 1 and the corresponding points of connection of emitters of transistors 5 and 7 with collectors of transistors 6 and 8 through additional windings 11 and 12 of positive feedback located on transformer 3,

The device works as follows.

The primary windings of the supply and control transformers 1 and 3 are supplied, rectangular voltages are shifted in phase by an adjustable angle. At the output terminals 4 and 2 of the device, a bipolar asymmetrical voltage is formed, the polarity of which at the instant of time depends on the polarity of the voltages coming from the secondary windings of the transformers 1 and 3. When the positive polarity of the voltage comes from the secondary winding of transformer I on the collector of the transistor fi and a positive gender rn zrti lo lo.tend to the base

transistor 6 from the secondary winding of the transformer 3, a positive polarity is formed at the output terminal 4. Transistor 5

at this time working in inverse

mode and the current through it is negligible. At the same time, the collector of the transistor 8 and the emitter of the transistor 7 receive a negative voltage from the secondary winding of the transformer 1. The emitter of the transistor 8 and the collector of the transistor 7 are supplied with a positive voltage of the secondary winding of the transformer 1 through the open transistor 6. In order for the transistors 7 and 8 were in the locked state, in the absence of resistors 10 it is necessary that the voltage of half the secondary winding of the transformer 3 is not less than the voltage of the two secondary half-transformers of the transformer 1, the presence of ba power resistors 10 leads to the fact that due to the fall of the voltage, or on the resistor 10 from the current flowing through the open transistor 6 and the load (through the emitter-base junction of the power transistor connected to terminals 2 and 4) on closed transistors 7 and 8, it will be equal to the voltage of one (in this case, lower) half-winding of transformer 1 plus the voltage of the emitter base of the power transistor connected by

5 to terminal 4. Thus, by introducing the resistors 10, the voltage of the secondary windings of the control transformer 3, which is necessary to create a mode, can be reduced.

0 lock transistors 5-7, about 1.5 times. There the most can be reduced to the same extent the power consumed by the control circuits of transistors 5-7 from the control transformer 3, t, e. increase the efficiency of the device.

Introduction to the device of two windings 11 and 12 located on the control transformer 3 allows 0 to further reduce the power consumed from the transformer 3, Windings 11 and 12 are included in the secondary winding circuit of the supply transformer 1 and form a positive

55 current feedback consumed by the power transistor from the device. The current of the transistor 5-8 depends both on the voltage across the primary winding of the transformer 3 and on the current consumed by the power transistor from the device. Emissions of a negative polarity current correspond to the dissipation of an excess charge in the base of the power transistor connected to terminals 2 and 4 of the device.

The most significant values of the consumed current of the voltage source by the transformer 3 arrive at times corresponding to the absence of the output current of the device. In the presence of the output current of the device, the base circuits of transistors 5-8 receive additional power from the secondary windings of transformer I, through the additionally introduced windings P and 12 of transformer 3. This manifests itself in an increase in voltage on the windings of transformer 3 at flow times. current load yct.

Selecting a transformaody coefficient from windings 11 and 12 -C to secondary windings of transformer 3, it is possible to ensure the current consumption by the primary winding of transformer 3 only at the moments when the device has no output current. It is also necessary to take into account the fact that the base resistances of resistors 9 are transformed into windings 11 and 12, therefore, choosing the optimal values of resistors 9 and transformation ratios, you can simplify the circuit by abandoning the ballast resistors 10. Their role will be played by resistors 9 transformed into windings 11 and 12. However, for greater reliability, it is necessary to rationally distribute the magnitude of the ballast resistance between the resistors 10 and the windings of the positive feedback. ,

The proposed device has a higher efficiency as the power consumed by the base circuits from the source of control voltage is significantly reduced. This allows the control transformer winding to be connected directly to the output of the operational amplifier without an intermediate power amplifier.

Claims (1)

DEVICE FOR CONTROLING A POWER TRANSISTOR, containing supply and control transformers, the middle terminals of the secondary windings of which are connected respectively to the first and second output terminals, the primary windings are connected to two sources of rectangular voltage, <phase-shifted by an adjustable angle, two pairs of transistors, and in each pair, the collector of the first transistor is connected to the emitter of the second, and the emitter of the first is connected to the collector of the second and second output terminal, the base of each pair of transistors through resistors under are connected to the corresponding extreme terminal of the secondary winding of the control transformer, which, in order to increase the efficiency, two additional resistors and two positive feedback windings of the control transformer are introduced into it, and additional resistors are connected by one terminal to the extreme terminals of the secondary windings of the supply transformer - 3 matora, and other conclusions through the corresponding windings of the positive feedback of the control transformer to the combined collector and emitter corresponding first pair of transistors.