SU1607056A1 - Single-ended d.c. to d.c. voltage converter - Google Patents

Abstract

This invention relates to electrical engineering and can be used in secondary power supply sources. The goal is to increase reliability by eliminating the biasing of the current transformer. The converter contains a transistor switch 1, a power transformer 3, the secondary winding 4 of which is connected via a rectifying diode 5 and a DLC filter 6 with output terminals, the input terminals of the transistor switch 1 are connected to the secondary winding 10 of a current transformer 8, the current winding 7 of which is connected through a capacitor 9 parallel to the input of the DLC filter 6. When a short unlocking pulse arrives from the output of the control unit 12 to the control winding 11 of the current transformer 8, the transistor switch 1 is unlocked and the resonant charge starts to capacitor 9 through the power transformer 3. At this moment a current proportional to the collector current flows through the input terminals of transistor switch 1. Since the current winding 7 of the current transformer 8 is included in the circuit of the measured current through the capacitor 9, no biasing of the current transformer occurs, which prevents its saturation. 3 il.

Description

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The invention relates to the field of electrical engineering and can be used in the sources of secondary power supply systems of radio engineering, automation and computer technology.

The aim of the invention is to increase the reliability of a single-ended DC / DC converter by eliminating the biasing of the current transformer.

FIG. 1 shows an electrical circuit of a single-ended DC / DC converter; Fig. 2 is a diagram of currents and voltages on converter elements; in fig. 3 shows an embodiment of the elements of a converter.

A single-voltage DC / DC converter contains a power transistor switch 1 and the primary winding 2 of the power transformer 3, the secondary winding 4 of which is connected to the output terminals through the rectifying diode 5 and the DLC filter 6, the current winding 7 of the current transformer 8 and the capacitor 9 connected in parallel with the input of the DLC filter 6, the secondary winding 10 of the current transformer 8 is connected to the control input of the power transistor club 1, and its control winding 11 is connected to the output of the control unit 12.

The power transformer 3 may be an independent design in which the primary 2 and secondary 4 windings are located on a common magnetic conductor. In addition, to provide the required value of the effective inductance of the scatter part of the primary or secondary winding can be performed on a separate magnetic circuit or without it.

The Converter operates as follows.

Upon the arrival of the triggering pulses (from the control unit 12) (see diagram 13, fig. 2), the half-wave of the current begins to flow through the primary winding 2 of the power transformer 3 (see diagram 14, fig. 2). When this current (in terms of secondary winding) exceeds (the time ti of Fig. 2) the load current (see diagram 15. Fig. 2), the half-wave of the charge current of the capacitor 9 begins to flow (see diagram 16, fig. 2) on which the voltage rises (see diagram 17, fig. 2). This current (see diagram 16, fig. 2) is transformed by current transformer 8 and fed to the control input of transistor switch 1 (see diagram 1.7 of fig. 2), thereby providing proportional current control of transistor switch 1.

At time t2 (see Fig. 2), the charge current of capacitor 9 changes sign (see, diagram 16, fig. 2) and its discharge begins (see, diagram 17, fig, 2) at control input 5 of the transistor of the key 1, a locking voltage is turned on (see diagram 18. FIG. 2). Thus, the acceleration of the absorption of the transistor switch 1 is ensured before the current through it is terminated

10 (from time point ts of fig. 2).

In the example of the specific embodiment (see FIG. 3), to ensure the required value of the effective inductance of the scatter part of the secondary winding 4

5 transformer 3 is made on a separate magnetic circuit. The transistor switch 1 is made on the basis of a bipolar pnp transistor 19 (see, Fig. 3), the base-emitter transition of which is bridged by a resistor 20 and a diode 21 (see Fig. 3). The control unit is a pulse generator on the basis of a unijunction transistor 22 (see Fig. 3) and connected through an amplifier based on transistor 23 to the primary winding

5 11 transformer 8 current (see Fig, 3).

In the case of proportional-current control, the transistor switch is automatically deactivated from the saturation state at the moment of switching off, which leads to a decrease in the absorption time.

There is practically no bias in the magnetic circuit of the current transformer 8 by turning on its current winding 7 in series with capacitor 9. All this significantly increases the reliability of the converter.

It should also be noted that in the proposed converter a leading (up to the current termination) start is provided

0 absorption of the transistor switch 1, which additionally contributes to increased reliability, due to the reliable closing of the transistor switch after the end of the operating current, which also leads to an increase

5 reliability of single-ended DC / DC converter.

Claims (1)

Invention Formula 0 Single-ended DC to DC converter containing a power transformer, the primary winding of which is connected through a trans-. retaining key between the input pins, and 5 The secondary winding is connected via a rectifying diode and a DLC filter with output terminals, a current transformer, the current winding of which is connected through a capacitor parallel to the input of the DLC filter, and the first output of the secondary winding is connected to the first input terminal of the transistor switch And it is also a hitch that, in order to increase reliability by eliminating the biasing of the current transformer, the control winding of the current transformer connected to the output of the control unit is inserted, and the second output of the secondary winding Current transformer current is connected to the second input terminal of the transistor switch. 18 FIG. 2 + 9 - about Fi.Z -H Udon