SU1480115A1 - Switching vevice - Google Patents

Abstract

The invention relates to a pulse technique and can be used in controllers and power supplies. The aim of the invention is to increase efficiency and speed. For this, a switching device containing a control transistor 1, a power transistor 2 of the same conductivity, an LCD filter containing a diode 4, an inductor 5, and a capacitor 8, has a transformer 10, the primary winding 11 of which is connected to the power transistor 2, the first secondary winding 12 is connected via the second diode 14 to the load 7, the second secondary winding 13 is connected via the first resistor 16 and the third diode 15 to the base-emitter junction of the control transistor 1. The efficiency and speed of the switching device are increased by reducing Now when turning on transistors 1.2 by reducing the amplitude and duration of the flow of through current through the power transistor 2, reducing the power of the control unit 3 by introducing positive feedback formed by the second secondary winding 13 of the transformer 10, use in the load the energy stored in transformer 10 when flow through the current, limiting the degree of saturation of the transistors and speeding up the switching process. 1 il.

Description

The invention relates to a pulse technique and can be used in regulators and modulators of radio transmitters, in secondary power sources.

The purpose of the invention is to increase efficiency and speed.

The drawing shows a circuit diagram of a switching device.

The switching device contains the control and power transistors 1 and 2 of the same type of conductivity, control unit 3, the first diode 4, the throttle 5, the first terminal of which is connected to the cathode of the first diode 4 and the emitter of the power transistor 2, the collector of which is connected to the collector of the control transistor 1 and busbar 6 power supply, the second output of the choke 5 is connected through the load 7, in parallel of which the capacitor 8 is connected, to the common bus 9, the transformer 10 to the primary winding 11 and the first and second secondary windings 12 and 13, the second and thirds diodes 14 and 15, the first, second and third resistors 16-18. The beginning of the primary winding 11 of the transistor 10 is connected to the anode of the first diode 4, the end of the common bus 9 and the beginning of the first secondary winding 12, the end of which is connected through the second diode 14 to the second output of the throttle 5. The beginning of the second secondary winding 13 of the transformer 10 is connected through a series-connected first resistor 16 and a third diode 15 to the base of the control transistor 1 and the first output of the control unit 3, the second output of which is connected to the end of the second secondary winding 13, the emitter of the control transistor 1 and the power base ranzistora 2, which includes parallel base-emitter junction of the second and third resistors 17 and 18, respectively.

The switching device operates as follows.

The control unit 3 generates signals with pulse-width modulation, which are fed to the base of the control transistor 1. When the transistor 1 is unlocked, the power transistor 2 also opens. The parameters of the LCD filter formed by the choke 5, the capacitor 8 and the diode 4, and the pulse frequency the controls are

0 5 0 5 0

0

that at the time of unlocking the transistor 2 a through current flows through it, which, passing through the primary winding 11 of the transformer 10, creates a voltage pulse in its second secondary winding 13, which is applied to the base of the control transistor 1 and provides a forced unlocking of the transistors. When the transistors are completely unlocked, the diode 4 is locked, the current through the primary winding 11 of the transformer 10 stops, which leads to a decrease in the base current of the control transistor 1 and a decrease in the overcharge in the transistor base and to limit the degree of saturation of the transistors. Simultaneously with the disconnection of the primary winding 11, the energy stored in the transformer at the time of the through current is transmitted to the load 7 by the first secondary winding 12. The load current flows from the power supply bus 6 through the open power transistor 2, the choke 5 and the load 7 to the common bus 9.

When the transistors are locked, the current due to the self-induced EMF of the droplets 5 closes along the primary winding 11 of the transformer 10 through the coupling 7, the capacitor 8 and the first diode 4. The second secondary winding 13 and in this case creates a positive feedback - provides the forced locking of the transistor 1 .

The second and third resistors 17 and 18, shunting the base-emitter transitions of transistors 1 and 2, respectively, contribute to the dissipation of charges in their bases and locking them.

Thus, the introduction of a transformer 10, the primary winding 11 of which is included in the power transistor 2 circuit, and the first and second secondary windings 12 and 13 are connected respectively to the load circuit 7 and the control circuit of the transistor 1, provides an increase in the switching device efficiency by reducing switching losses transistors 1 and 2 by reducing the amplitude and duration of the flow of through current through the power transistor 2, reducing the power of the control unit 3 by introducing positive feedback, using load energy stored in the transformer 10 during the flow of through current, as well as

314801

provides improved performance by limiting the degree of saturation of transistors and speeding up the switching process.

Claims (1)

Invention Formula A switching device containing a control and a power transistor of the same conductivity type, a control unit, a first diode, a choke, the first terminal of which is connected to the cathode of the first diode and the emitter of the power transistor, the collector of which is connected to the power supply bus, the second terminal of the chokes, is connected via a load parallel to which a capacitor is connected, with a common bus, which is due to the fact that, in order to increase efficiency and speed, a transformer is introduced five" with primary and first and second secondary windings, second and the third diode, the first resistor, with the beginning of the primary winding of the transformer connected to the anode of the first diode, the end of the common bus and the beginning of the first secondary winding of the transformer, the end of which through the second diode connected to the second output of the throttle, the beginning of the second secondary winding of the transformer is connected through serially connected the first resistor and the third diode to the base of the control transistor and the first output of the control unit, the second output of which is connected to the end of the second secondary winding of the transformer, the base of forces transistor and the emitter of the control transistor whose collector is connected to the power supply bus.