SU847305A1 - Stabilized dc voltage source - Google Patents

Description

(54) STABILIZED SOURCE OF CONSTANT

VOLTAGE I

The invention relates to electrical engineering and can be used in various electric power devices and radio equipment and communications equipment.

Stabilized DC sources are known, which contain a medium-voltage power transformer with a secondary winding, a rectifier, a control transistor and an output filter lJ.

The disadvantage of such circuits is the low efficiency, caused by the sequential switching on of the rectifier diodes and the control transistor.

Also known are stabilized power sources used to obtain low voltages on the load.

However, in known sources, to improve the efficiency, the rectifier is made on transistors.

The closest in technical essence to the proposed invention is a stabilized source of constant voltage, containing two regulating transistors, a power transformer with an output winding with a midpoint, to the ends of which are connected the emitters of regulating transistors, an output filter connected by its input between the point of connection of the collectors of regulating transistors and common bus connected to the midpoint of the output winding, and the output connected to the output terminals of the stabilized source, and knots l regulatory control transistors,

The disadvantage of this stabilized source is the imperfection of the control transistor control circuit, which limits its scope.

The purpose of the invention is to expand the functionality of the stabilized source.

Claims (2)

This is achieved by the fact that the stabilized source is equipped with a control transistor connected to the common bus by the emitter, two zener diodes, the anode of the first one of which is connected to the common bus, and the cathode through the second zener diode and the first resistor with a positive output terminal, the opto-optical emitter of which is connected parallel to the first Zener diode, and the light receiver is parallel to the base-zmitter junction of the control transistor J and forward diodes connected by anodes to the ends of the secondary winding and of the second resistor - control with base transistor yuscheg and decoupling diode anode connected to the bases of the corresponding regulating transistor and the combined cathodes via a third resistor - to the collector of the control transistor th present, and parallel to the emitter-base transition of each control transistor is switched on a shunt resistor. The drawing shows the principle: a pial circuit of a stabilized DC voltage source, the source contains control transistors 1 and 2 with their emitter-base transitions connected in parallel by shunt resistors 3 and 4, the control transistor 5, the first and second zener diodes 6.7 and the first resistor 8, connected to the positive output terminal of the source, the optocoupler 9, the light emitter 10 of which is connected parallel to the first one is stable to ron 6, and the light receiver I1 is parallel to the transition emitter-base of the transistor 5, e diodes 12 and 13, the rectifier diodes 14 and 15, second 16 and third resistors 17, power transformer 18 and output filter 19 connected to the positive Nome 20 and negative 21 output terminals source. The load is connected to the terminals 22. The stabilized source operates as follows. In the first half period of the input alternating voltage, diode 15 is in the conducting state. Through diode 15 and resistor 16, the base current of transistor 5 flows, which opens c. Through the half of the output winding of the transformer 18, the emitter-base junction of transistor 1, diode 12 and resistor 17 is flowing-current, causing transistor 1 to turn on and voltage to rise at the source output. When the output voltage reaches the Zener diode 6 and 7, the Hbie zener diodes are punctured, the current flows through the light emitter 1Q of the optocoupler 9, the resistance of the photodetector 11 of the optocoupler 9 decreases sharply, which leads to the locking of the transistor 5 and, as a result, the transistor 1, whose closed state This is provided by a resistor 3. The current in load 22 is supported by the output filter choke 19. When the voltage drops below the voltage, the breakdown of the zener diodes 6 and 7 the current through the zener diodes 9 and the light emitter Ø of the optocoupler 9, the resistance of the photodetector 1 1 sharply increases, the transistor 5 opens, through the resistor 3, the diode 12, the resistor 17, the transistor 5 current flows, the transistor 1 turns off the energy from the transformer 18 is transferred to the load 22. The cycle of the circuit is repeated during the first half period input th voltage with frequency; ; determined by the parameters of the filter 19 and the feedback circuit consisting of - zener diodes 6 and 7, an optocoupler 9 and a transistor 5. In this case, the regulating transistor 2 is locked with a shunt resistor 4. In the second half-period of the input voltage, the regulating transistor 1 is closed shunt resistor 3, the diode 15 is locked, and the diode 14 is open, which provides the ability to control the transistor 2. Thus, the proposed source scheme allows in one single functional unit to provide straightening and stabilizing functions, which allows extending the functionality of the source. Claims of Invention A stabilized constant voltage source containing a power transformer with an output winding with a midpoint, to the ends of which the emitters of the first and second control transistors are connected.