SU1413693A1 - Single-ended d.c. voltage converter - Google Patents

Abstract

The invention relates to electrical engineering and m. used in the systems of secondary power supply and control of constant voltage,. The purpose of the invention is to search for. The power transistor 1 is controlled by the transformer 2 current a from the switching on 7 and switching off 10 transistors, which switch the direction (forward and reverse) of the base current of the power transistor 1. The transistors 7 and 10 are controlled by the UCHHX synchronization pulses 1 is turned on, and in its absence it is turned off. To create a blocking pulse of the base current of the power transistor 1, the collector current reversal is used, which exists while the transistor is in a state of depression due to the inertia of absorbing excess carriers in the semiconductor structure of the power transistor. In this device, the resistor, which is part of the damper. is also used to start the converter. 1 з, п, ф-л, 1 Il.

Description

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The invention relates to electrical engineering, and can be used in secondary power supply systems to convert and regulate: voltage nocTonFiHoro voltage.

The purpose of the invention is to increase the efficiency. In the drawing, a diagram of the proposed converter is shown.

The converter contains a power transistor 1 connected in series with the primary winding W of the current transformer 2 and the load 3 to the power supply E. Parallel to the current transformer 2, and if the current is sufficient for the collector 1, the transistor 1 stays on the circuit consisting of damping

; diode 4 and damping capacitor

5. Their connection point is connected via the starting resistor 6 to the collector 20 of the switching-on transistor 7 and through the shield diode 8 to the + E terminal of the primary power source. The base of the transistor 7 is the input of synchronization pulses U, and the emitter is a subconnector of the diverter.

C nnh-

to the base of the power transistor I and. During the operation of the positive end of the switching winding W rytsd

current transformer 2, the beginning of which

through the switching diode 9 is connected to

switch-off transistor 30 collector

10. Start of turn-on winding W

current transformer 2 is connected through

including diode 11 with collector

the switching transistor 7 and through the pack

Tensioning the damping capacitor 5 and the starting resistor 9. With the appropriate ratios of the collector current of the power transistor 1 and the starting resistor 6, the power transistor 1 opens and enters the center. The saturation mode is determined by the current gain of transistor 1. After the occurrence of the collector current of transistor 1 and when the transistor 7 is open, the positive feedback of the windings W and Wg is activated ((

due to this positive feedback, and if it is insufficient, due to the continued current flow through the starting resistor 6 from the voltage source - capacitor 5. This ensures that the circuit operates both in discontinuous current mode and in continuous current mode. the pulse Vf.J, the power transistor 1 remains saturated, and the damping capacitor 5 is discharged through a resistor 6. By this, the voltage accumulated on it is reduced to the required level. Thus, the use energy of the damping capacitor 5, which is uselessly consumed in the known circuits, ensures the start of the power transistor with the start of its turning on and ensuring its steady state in a given initial shaft shaft after unlocking.

the equal diode 2 and the first base resistor 13 are with the base of the switching transistor 10. Moreover, the second base resistor 14 is connected between the base and the emitter of this transistor, and the emitter of the transistor 10 is connected to the end of the switching winding of the current transformer 2, the emitter of the power transistor 1 and. power supply pole.

The voltage converter operates as follows.

The initial position of the circuit: the power transistor 1 is locked, its collector current paBeif zero, turning on 7 and turning off 10 transistors also locked. At the input of U (- there is a zero potential. The damping capacitor 5 is charged to the voltage that is present on the collector of the power transistor 1.

When a positive pulse UCHHX arrives, the switching-on transistor 7 opens, its 1 electrolyte current, which is the base current of the power transistor 1, is determined by

current transformer 2, and if the collector current is sufficient, transistor 1 remains

Tensioning the damping capacitor 5 and the starting resistor 9. With the appropriate ratios of the collector current of the power transistor 1 and the starting resistor 6, the power transistor 1 opens and enters the center. The saturation mode is determined by the current gain of transistor 1. After the occurrence of the collector current of transistor 1 and when the transistor 7 is open, the positive feedback of the windings W and Wg ((current transformer 2, and if the collector current is sufficient) , the transistor 1 remains

razovatel.

due to this positive feedback, and if it is not enough, then due to the continued current flow through the starting resistor 6 from the voltage source - capacitor 5. This ensures that the circuit operates both in discontinuous current mode and in continuous

of the high-voltage pulse Vf.J, the power transistor 1 remains saturated, and the damping capacitor 5 is discharged through a resistor 6. By this, the voltage accumulated on it is reduced to the required level. Thus, the use energy of the damping capacitor 5, which is uselessly consumed in the known circuits, ensures the start of the power transistor with the start of its turning on and ensuring its steady state in a given initial shaft shaft after unlocking.

The switching-off transistor during the open state of power 1 and including 7 transistors is closed, since the ratio of resistors 13 and 14 is chosen such that the input voltage of the transistor 10 is not enough to unlock it.

After finishing them positive

pulse Uj. (the switching-on transistor 3 is locked, however, the power transistor 1 remains in its current state due to the inertia of charge dissipation from its semiconductor structure. The voltage on the winding Wj of the current transformer 2 increases, which unlocks the switching-off transistor 10. The voltage of the current transformer 2 increases. open, creates in the base circuit of transistor 1 a reverse (dissipative) current. Further, if

Off on, the transistor 10 remains open throughout the reverse current. The forced resorption of charges from begins. structures of the transistor 1. After termination of resorption, the collector current of transistor 1 is reduced, and then the current through the winding Wgj ,, and the base reverse current also decreases. The front of the collector voltage of the power transistor 1 is formed.

Since at the previous stage of operation of the circuit, the damping capacitor 5 was partially (or completely) discharged through the starting resistor 6, when the front of the collector voltage is formed, there is a lag (in time) of the voltage relative to the collector current. This ensures a reduction in the instantaneous power of the switching losses of the power transistor, as well as in the known schemes with damping circuits. The protective diode 8 serves to reduce the voltage on the collector of the turn-on transistor 7, which in this case cannot exceed the voltage with a higher voltage across the capacitor 5 during the locked state of the transistor 1.

Using a damping resistor at the same time to start up the converter increases the efficiency.

Claims (2)

1. A one-voltage voltage converter containing a strainer. An emitter connected to the first supply output of the converter and connected by a chain of series-connected damping diodes and a capacitor, a current transformer whose primary winding is connected in series to the collector circuit of the power transistor and the winding is connected in one step connected to the emitter of the power transistor, and another output through the switching diode to the collector of the switching transistor, the emitter of which is coi fi, Kiie.H with the base of the power transistor, and a starting resistor, connected by one output to a collector of the switching transistor, characterized in that, in order to increase efficiency, the second output of the starting resistor is connected to the connection point of the damping diode with the damping capacitor. 2. Converter n. l, characterized in that introduced protective diode connected between the collector of the turn-on transistor and the second power supply of the converter.