SU957381A1 - Two-cycle self-excited converter - Google Patents

Description

(Sk) TWO-TONE SELF-EXCITING CONVERTER

one

The invention relates to converter equipment; in particular, to transistor converters, and can be used to supply direct current to radio electronics devices.

Known push-pull self-drive transistor converters SG. and 2.

Some of the known devices have lower efficiency due to the lack of active locking of the transistors. Others have a complicated output transformer design.

In addition, in the above-mentioned converters, it is difficult to control and set the desired switching frequency, depending on the parameters of the output transformer.

Closest to the proposed technical entity is a push-pull ham-exciting converter containing two main transistors, the emitters of which are combined

Both are connected to the first input terminal of the converter, and an output transformer, the ends of the primary winding of which are connected to the collectors of the main transistors, and the outlet from the midpoint of this winding is connected to the first terminals of the two time of the driving resistors and the second input terminal of the converter, and the capacitor Z.

ten

The disadvantages of the known converter are lower efficiency due to the low steepness of the switching fronts of the main transistors, depending on the duration of the charge;

Claims (3)

15 capacitors; incomplete use of the main current transistors, since part of their collector currents serves to recharge the time of the driving capacitors; the difficulty of the liver is of a symmetric mode of operation due to the presence of two time-setting capacitors with a technological variation of the ratings. The purpose of the invention is to increase the efficiency of the converter. The goal is achieved by the fact that two field-effect transistors are introduced into the converter, the gates of which are connected to the collectors, the drains are connected to the bases of the main transistors, and the sources are connected to the second terminals of the time of the setting resistors and connected to each other through the aforementioned capacitor. The drawing shows the scheme of the proposed push-pull self-excited converter. The converter contains main transistors 1 and 2, connected by collectors to the ends of the primary winding of the transformer 3. whose secondary winding is connected to load 5 via rectifier k and connected to the load 5. The field-effect transistors 6 and 7 are connected by sources with time reference resistors 8 and 9 and connected interconnected through a capacitor 10. Other inputs. The time of the setting resistors is connected to the input terminal 11 of the converter. The emitters of the main transistors 1 and 2 are connected to the second input terminal 12 of the converter. In the process of converter operation, alternating switching of transistors 1 and 6, 2 and 7 occurs from the open to the closed state and vice versa. In the considered period of time, transistors 1 and 6 are open, and transistors 2 and 7 are locked. The open state of transistor 1 provides, with the current flowing through the circuit, the input terminal 12 of the converter — the emitter junction of transistor 1 — the field effect transistor. 6 - time driving resistor 8 - input terminal P of the converter. The open state of the field-effect transistor 6 is ensured by the fact that its gate through an open collector junction of transistor 1 is connected to the drain. Transistor 2 is locked because the field-effect transistor 7 is locked. The latter, in turn, is in the closed state, because its gate voltage - source is greater than the threshold. The capacitor 10 is charged by the current flowing through the circuit input terminal 12 - emitter junction of transistor 1 - field-effect transistor 6, capacitor 10 - time setting resistor E input terminal-11. As the capacitor 10 charges, the gate voltage decreases - the source of the field-effect transistor 7 And when the threshold is reached, the latter starts to open, which in turn causes the transistor to open 2. At the same time, the voltage at its collector junction decreases, and, consequently, the gate voltage of the field-effect transistor 7 decreases, and the latter is further unlocked. When the transistors 2 and 7 are unlocked, the voltage of the capacitor 10 is applied with a locking polarity to the emitter junction of transistor 1, due to which there is an avalanche-like process of locking transistors 1 and 6. In the new temporarily stable state, when transistors 1 and 6 are closed, and transistors 2 and 7 are open, the capacitor 10 is recharged along the circuit of the input terminal 12 - emitter junction of transistor 2 - field-effect transistor 7, capacitor 10 time driving resistor 8 - Input terminal 11. Then the described processes are repeated for the other arm c we. In contrast to the known converter, the proposed device has a higher efficiency, since power losses are reduced when switching transistors. The main transistors of the converter are more fully used for the current, since they do not overcharge the drive capacitor through them. It is easier to ensure symmetrical operation of the converter, because the duration of both temporarily stable states is determined by the capacity of one capacitor. The symmetrical mode of operation of the converter, in turn, allows more complete use of the magnetic properties of the transformer core, and, thereby, reduce its dimensions and mass. Formula of an Investigation A push-pull self-exciting converter / containing two main transistors, the emitters of which are combined and connected to the first input terminal of the converter, and an output transformer, the ends of the primary winding of which are connected to the collectors of the main transistors, and the removal from the midpoint of this winding connected to the first terminals of the two timing resistors and the second input terminal of the converter, and a capacitor, characterized in that, in order to increase efficiency, two field-effect transistors are inserted, the gates of which are connected to the collectors, the drains are connected to the bases of the main transistors, and the sources are connected to the second the pins of the master resistor times and are interconnected through the aforementioned capacitor. 57381 Sources of information taken by time attention in the examination one . US patent tf 2963558, cl. 331-113, I960. 5 V 2. Moin B.C. Laptev N.N. Stabilized transistor converters. M., Energie, 1972, p. 8, fig. 1-2a 3. Stepanenko I.P. Fundamentals of the theory of transistors and transistor circuits. M., Energie, 1977, p. 6T ", fig. rice .