SU1070675A1 - D.c.voltage converter - Google Patents

Abstract

A CONSTANT VOLTAGE TRANSMITTER, stator connected, respectively, to the input and output pins, two series-connected transistor switches, each of which includes a transistor, a damping diode, the cathode of which is connected to the collector of the transistor, and the control transformer winding, which have a switch, which are connected. In order to simplify, in each transistor switch between the emitter of the transistor and one of the ends of the winding of the control transponder, two series-connected resistors are connected, KOTOIX IX compound point between a snubber diode connected to the anode and another konets.obmotki control transformer connected kb tran§ ican directly.

Description

The invention relates to electrical engineering and can be applied in DC voltage sources that use an intermediate conversion of a DC voltage to a high frequency alternating voltage. A known DC / DC converter is used, which contains a transistor switch, which uses a damping diode, a power transformer winding, a resistor and a diode that makes up the power supply of the damping diode C12. In this converter, to reduce the peak power released during a turn-off of the transistor, a damping diode, which increases the average power in the load and increases the reliability of the transistor switch. The disadvantage of this converter is the complex circuit of powering the damper diode, which reduces the weight and dimensions of the converter. The closest to the present invention is a DC to AC converter containing connected to the input and output terminals respectively; two series-connected transistor switches, each of which includes a transistor, a damping diode, the cathode of which is connected to the collector of the transistor, and winding of control transformer 2 3. The disadvantage of the known converter is the undersized dimensions due to the complex circuit of the damping diodes. I The purpose of the invention is to simplify the converter circuit. The goal is achieved by the fact that in a DC converter containing two series-connected transistor switches connected to the input and output pins, each switch from a KOTopbtx includes a transistor, a damping diode, the cathode of which is connected to the transistor collector, and a control winding of each transistor switch between the emitter of the transistor and one of the ends of the winding of the control transformer, two series-connected resistors are connected, to the connecting point Neny koto | Zh1h between a snubber diode connected to the anode, and the other end is controlled kadegr transformer winding is connected directly to the base of the transistor. FIG. 1 shows the electrical circuit of the proposed device; in fig. The 2 nd voltage profiles characterizing the operation of the device circuit. The device (Fig. II contains two successively middle transistor switches 1 and 2, each of which includes a transistor 3, a damping diode 4, a winding 5 of the control transformer, one end connected to the base of transistor 3 and the other through resistors 6 and 7 - to the emitter of the same transistor, while the damping diode 4 is connected by a cathode to the collector of transistor 3, and the anode to the connection point of resistors 6 and 7. Fig. 1 also shows an example of connecting the converter to a constant voltage source Of, and to the load 8 using e The circuit divider 9. The circuit works as follows: If there is a positive control voltage 2 (Fig. 2, the transistor 3 of the switch 2 is open and saturated, the damping diode 4 is blocked by a negative voltage across the resistor 6 arising from the flow of control current. When the field changes of the control voltage at the time -t ,, begins the process of resorption of excess charges in the base transistor 3 with the duration tp (Fig. 26). At the same time, a direct current begins to flow through the damping diode 4 caused by a positive voltage at the lower end of the control winding 5 relative to the collector of the saturated transistor 3. The direct current through diode 4 is determined by the ratio of resistors b and 7, and the duration is. The stability is tp (Fig. 2c). At time t, the high resistance of the collector junction of transistor 3 is restored, the current jf (, fig. 2 b) through it is discontinued and the voltage UK (fig.2g) on the collector of transistor 3 begins to increase. When the voltage on the collector reaches the voltage The control winding of the transformer is reversed through the diode. The reverse current is closed through the resistor 6 into the common load circuit. On the time interval i - i2, the reverse resistance of diode 4 is restored and the load current is finally turned off (Fig. 2 bK. From the graphs of Fig. 2 a, 2 g, it can be seen that the voltage on the collector of the transistor increases over time, when the collector current is already zero, all the dynamic power is turned off when the power is turned off in the damping diode. Similarly, the second transistor switch of the converter operates in antiphase. In the proposed converter, dynamic loads on the transistors are excluded at the stage of switching them off.

but with fewer elements in the scheme.

Thus, the use of the proposed device simplifies the converter circuit, makes it possible to exclude reverse diodes from the circuit. When choosing a resistor b 1 FIG. 1) of a sufficiently small size or by shunting it with a low-voltage Zener diode 10 (shown by dashes), the damping and diodes 4 simultaneously perform the role of reverse diodes in the converter. At the same time, the zener diode can protect the transistor from being re-opened by the voltage across the resistor 6 caused by the reverse current of the damping diode. In addition to this, the proposed device provides a higher efficiency due to the decrease in the time of flow of direct current through the damping diode, and consequently, the reduction

0 power dissipated when in the circuit of its power.

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Claims (1)

A DC / DC converter containing + transistor switches connected in series to the input and output terminals, each of which includes a transistor, a damping diode, the cathode of which is connected to the transistor collector, and a control transformer winding, characterized in that, with In order to simplify, in each transistor key between the emitter of the transistor and one of the ends of the winding of the control transformer, two series-connected resistors are connected, to the point Inonii which is connected between an anode snubber diode and the other end of the control winding of the transformer ¹ is connected directly k'baze transistor. <3 Figure 1, 1070675