SU993405A1 - Converter - Google Patents

Description

(5) CONVERTER

one

The invention relates to electrical engineering and can be used as a secondary source of power for electronic equipment.

A known DC / DC converter contains power transistors, the emitters of which are combined, and shunt diodes are connected counter-parallel to the base-emitter junction, an output transformer whose positive feedback winding is connected between the bases of the power transistors through the current limiting resistor G1 1

The disadvantage of this converter is low efficiency due to the power loss in the transistors and the transformer, which increases with increasing conversion frequency.

Closest to the proposed is a converter containing two transistors, the emitters of which are combined, and shunt diodes connected in the opposite direction, an output transformer, the positive feedback winding of which is connected to the first output of the winding of the switching throttle, connected to the base-emitter junction and another output through two series-connected limiting resistors - with the base of the first transistor, and

The 10 points of the mentioned resistors connected to the second output of the winding of the switching Drossel, and the bases of the transistors are interconnected through two displacement resistors, the middle of which is connected to the midpoint of the opposite diodes and the second output of the 20 emitters of the transistors 2.

A disadvantage of the known converter is its complexity.

Claims (2)

The purpose of the invention is to simplify the converter and increase its reliability. 3 The goal is achieved by the fact that said diodes are connected in parallel with the positive feedback winding, and the first output winding of the switching throttle is connected to the base of the second transistor through an additional limiting resistor. The drawing shows the electrical circuit of the converter. The converter contains transistors 1 and 2, an output transformer 3 with a winding 4 positive feedback connection, switching choke 5, shunt diodes 6 and 7, diodes 8 and 9, capacitor 10, limiting 11-13 and bias T and 15. Eliminator resistors 16, filter 17, load 18. The converter operates as follows. When the converter is turned on, transistor 1 opens. This leads to the appearance of voltage on the winding 4 of transformer 3, under the action of a circuit consisting of limiting resistors 11 and 12, a base-emitter junction of transistor 1 of diode 7 and an additional limiting resistor 13, current flows holding the transistor 1 in the open and saturated state, and the transistor 2 in the closed state. At the same time, the choke 5 begins to change the commutation voltage, for example, in the + Bj direction, the capacitor 10 is charged through diode 9. The presence of Nogo capacitor 10 current, flowing through a transistor base circuit 1, the latter accelerates the process of incorporation. After the switching drossel 5 is saturated, the diode 9 is locked and the base-emitter circuits of transistors 1 and 2 through the bias resistors I and 15, respectively, apply a reverse (negative) voltage of the capacitor 10, under the action of which the transistor 2 is held in the closed state and The base circuit of transistor 1 accelerates the resorption of minority charge carriers. A decrease in the magnetizing current of the transformer 3 leads to a change in the polarity of the voltage on the winding A. As a result, the transistor 2 goes into the open and saturated state, and the transistor 1 goes into the closed state: the switching choke 5 begins to reverse the direction of rotation, i.e. towards B. Simultaneously, a current flows through the diode 8, charging the capacitor 10, which accelerates the process of turning on the transistor 2. Then the processes proceed as described. The alternating voltage of the transformer 3 through the rectifier 16 and the filter 17 is supplied to the load 18. Thus, the invention accelerates the switching processes of the transistors, i.e. reduces the dynamic power loss in them, which increases the reliability of the converter. Claims of the Inverter containing two transistors, the emitters of which are combined, and the base-emitter transitions are connected shunt diodes connected in the opposite direction, the output transformer, the winding of the positive feedback of which one output is connected to the first output winding of the switching throttle, and the other output through two series-connected limiting resistors - to the base of the first transistor, with than the middle point of the mentioned resistors is connected to the second output of the switching coil winding, and the bases of the first and second transistors are connected to each other via two bias resistors, the middle point of which is connected to the middle point of opposite diodes and the second output of which is connected to emitters transistors, that is, in order to simplify and increase the reliability of the converter, the mentioned diodes are connected in parallel to the winding of the positive feedback, and the first output d the winding of the switching throttle is connected to the base of the second transistor through an additional limiting resistor. Sources of information taken into account in the examination 1 .. Electronics, 1970, No. 19, p.39. 2. USSR author's certificate №, cl. H 02 M 3/335, 1978. sixteen 18 DD 4 . P% A