SU1610560A1 - Single-ended d.c. voltage stailizer - Google Patents

Abstract

The invention relates to the field of electrical engineering and can be used in secondary power supplies. The goal is to improve the weight and dimensions. The converter comprises a power transistor 1 connected in series with the primary winding of the output transformer 2 and the power source. Between the collector of the power transistor 1 and the power supply, an electrical energy recovery circuit is included, consisting of capacitor 3, one plate of which is connected to the second input terminal, and the second plate through diode 4 is connected to the collector of power transistor 1. The connection point of diode 4 and capacitor 3 is connected emitter of auxiliary transistor 5. During the charging of capacitor 3 (when locking the power transistor 1), the auxiliary transistor 5 is locked with a voltage drop across diode 4, which prevents shorting of the primary winding Nogo transformer 2. 1 yl.

Description

The invention relates to electrical engineering and can be used in secondary power sources. 5

The aim of the invention is to reduce the mass and dimensions of the Converter.

The drawing shows a diagram of the Converter. Ιθ

The converter contains a power transistor 1 of the p-rp type, connected in series with the primary winding of the output transformer 2 and a power source, a capacitor 3, 15, one lining of which is connected to the first input terminal of the converter, and the second lining through a diode 4, • connected to it by a cathode connected to the collector of the power transistor 1. 20 An emitter of the auxiliary transistor 5 of the structure is connected to the intermediate point of the diode 4 and the capacitor 3, the base of which is connected to the collector with 25 through a current-limiting resistor 6 ohm power transistor '1 ^,: and between the collector of the transistor 5 and the second input terminal of the Converter is turned on in the forward direction cut-off diode 7. 30

Single-ended Converter DC voltage operates as follows.

In the initial position, when the supply voltage is applied to the input terminals of the converter, the transistor 1 is locked and the capacitor 3 is charged through the primary winding of the output transformer 2 and diode 4 to the supply voltage. The potential difference between the base and emitter of transistor 5 is zero, and it is locked. The cut-off diode 7, which serves to prevent breakdown of the collector-emitter junction of the transistor 5 by a voltage of reverse polarity at the moment of switching on the supply voltage, is also closed.

When a control voltage pulse is applied to the base of the power transistor 1, the latter opens and a current flows through the primary winding of the transformer 2. The voltage at the emitter of transistor 5 with respect to its base becomes positive, a base current appears, limited to an acceptable value by resistor 6, and transistor 5 is unlocked. However, the collector current of the transistor 5 does not flow, since the diode 7 is locked.

'At the end of the action on the base of the transistor 1 of the control pulse, the collector current of the transistor 1 begins to decrease. Due to this and the constancy of the current in the inductance of the output transformer 2, a decrease in current should cause a rapid increase in the collector voltage of the transistor 1. However, at this moment, the diode 4 opens, and a capacitor 3, previously charged to the supply voltage, is connected in parallel to the transistor 1. With a sufficiently large capacitance of the capacitor 3, a slight increase in the voltage is achieved due to the generation of energy stored in the inductance of the output transformer 2 during the active part of the converter operation cycle. During the charging of the capacitor 3, the transistor 5 is closed by the voltage drop applied to the base, positive with respect to the emitter, on the open diode 4. This eliminates the shorting of the primary winding of the transformer 2 to itself through the transistor 5, After the energy stored in the inductance of the transformer 2 is consumed by the current of the capacitor 3 the charge decreases to zero and the diode 4 closes. Due to the fact that the potential of the upper one according to the circuit diagram of the capacitor 3 becomes larger than at the second input terminal, the voltage at the emitter of transistor 5 becomes positive with respect to its base and collector, transistor 5 and diode 7 open and capacitor 3 is discharged to the supply voltage , returning the stored energy to a power source. The circuit is reset. Subsequently, the processes are repeated.

Thus, the invention allows to reduce weight and dimensions by eliminating the throttle from the converter, as well as to simplify its circuit and increase reliability, since. it contains fewer elements.

Claims (1)

Claim A single-ended DC-voltage converter containing a power transistor is connected to the input terminals through the primary winding of the output transformer, with a point 1610560 connecting the collector of the power transistor to the first terminal of the primary winding of the output transformer, the second terminal of which is connected to the first input terminal, through a current-limiting resistor connected to the base of the auxiliary transistor of the opposite type of conductivity relative to the power transistor, connected in series d and a capacitor shunting the collector-emitter circuit of the power transistor, characterized in that, in order to improve the overall dimensions, the diode is connected between the power collector 5 and the emitter of the auxiliary transistors, while the power transistor emitter connected to the second input terminal is connected also to the free terminal О of the capacitor, and the collector of the auxiliary transistor is connected to the first input terminal through a directly biased input cut-off diode.