SU1577008A1 - Device for controlling power transistor - Google Patents

Abstract

The invention relates to converter equipment and can be used in the design of sources of secondary power supply for power components of electronic equipment. The aim of the invention is to increase the speed of unlocking and locking the power transistor. The goal is achieved by the fact that a reverse conduction transistor 8 is inserted in the device, which with the help of a capacitor 7 keeps the transistor 2 in the open state if it is necessary to lock the power transistor 1. 1 Il.

Description

The invention relates to electrical engineering and may find application in power supply units of automation, telemechanics, computer equipment and communications, 5

Transistor 2 is turned on and provides for the absorption of excess charges in the base region of transistor 1 along the circuit - capacitor 12, resistor 14, transistor 2, resistor 13.

The purpose of the invention is to increase the speed of the device, reducing the switching fronts of the power transistor.

The drawing shows a schematic diagram of a device for controlling a power transistor.

A device for controlling a power transistor 1 contains a control transistor 2 of reverse conductivity, a first resistor 3 connected between the emitter of the power transistor 1 and the secondary winding of the transformer 4, the beginning of which through the first diode 5 is connected to the base of the transistor 1, and the end through the second resistor 6 and sequentially with it, the included capacitor 7 is connected to the base of the additional transistor 8. A third resistor 9 is installed between the emitter and the base of transistor 8.

The end of the secondary winding of the transformer 4 through a resistor 10 and a second diode Ϊ1 is connected to the emitter of the transistor 8 and through the storage capacitor 12 to the emitter of the switching transistor 1. The connection point of the terminals of the capacitor 12, diode 11 and the emitter of the transistor 8 through a resistor 13 is connected to the collector of transistor 2. Between the emitter and the base of the transistor 1 includes a resistor 14.

The device operates as follows.

Switching the transistor 1 from a closed state to an on state occurs under the influence of a positive voltage of the secondary winding of the transformer 4.

The base current of transistor 1 is created in two circuits: the first is diode 5, the emitter-base transition of transistor 1, the resistor 3, the tap of the winding 4, and the second is pulsed current in the circuit - diode 5, emitter-base transition of the transistor 1, storage capacitor 12 , resistor 9, capacitor 7, resistor 6, diode 11, resistor 10.

The pulse current forces the inclusion of transistor 1.

Under the influence of the voltage of the winding 4, the capacitor 12 is charged.

When the voltage on the winding of the transformer 4 disappears, the capacitor 12 gives off the accumulated charge to the circuit - resistor 14, the emitter-base transition of transistor 2, the secondary winding of the transformer 4, resistor 6, capacitor 7, the emitter-base transition of transistor 8. The transistor 8 is turned on and boosts the base current transistor 2.

The pulse current through the capacitor 7 holds the transistor 8 in the on state and provides saturation of the transistor 2, thereby achieving an accelerated 10 switching of the power transistor 1.

When the transistor 1 is turned off, a locking voltage is supplied to its base from the capacitor 12 through the emitter collector of transistor 2 and from the winding 4 through 15 of the circuit - resistor 3, resistor 14, the emitter-base transition of transistor 2. and reliably holds transistor 1 in the on state ..

Claims (1)

20 claims A device for controlling a power transistor containing a pulse transformer, the primary winding of which is designed to be connected to a source of control pulses, the beginning of the secondary winding is connected to the anode of the first diode, the cathode of which is connected to the first output of the first resistor, intended to be connected to the base of the power transistor, for connecting to the emitter of which the second terminal of the first resistor and the first terminal of the first capacitor are designed, the second terminal of which is connected 35 to the first terminal of the second res the source and the anode of the second diode, the cathode of which is connected to the end of the secondary winding of the pulse transformer, the beginning of which is connected to the base of the reverse conductivity transistor, 40 emitter of which is connected to the first output of the first resistor, the third and fourth resistors, characterized in that, in order to improve performance, introduced the fifth and sixth resistors, the second capacitor and direct-current transistor, the collector of which is connected to the middle terminal of the secondary winding of the pulse transformer and the first terminal of the third resistor RA, the second terminal of which is connected to the second terminal of the first resistor, the base of the forward conductor transistor connected to the end of the secondary winding of the pulse transformer through a chain of sequentially connected second capacitor and fourth resistor and directly to the first terminal of the fifth resistor, the second terminal of which is connected to the emitter of the direct transistor conductivity and anode of the second diode, the cathode of which is connected to the first terminal of the sixth resistor, the second terminal of which is connected to the end of the secondary winding pulse transformer. and the collector of the reverse conductivity transistor is connected to the second terminal of the second resistor.