SU1467550A1 - Stabilized d.c. voltage converter - Google Patents

Abstract

The invention relates to the field of electrical engineering and can be used to build stabilized sources of electrical power for electronic equipment. The aim of the invention is to improve the stability of the output voltage. The device is made according to the scheme with parallel connection of the power transistor 3, which, together with the first 8 and second; 9 transistors of the control unit 7 comprise a controlled multivibrator. The output voltage is stabilized due to the pulse-width modulation of the signal of the control unit 7 by varying the maximum magnetic flux of the power droplet 1 and changing the maximum collector current of the power transistor 3. The control unit 7 generates a control voltage that turns the control voltage on and off power transistor with a certain frequency and duration, ensuring the stability of the output voltage with a given accuracy. 1 il. 2 & about: . ate

Description

The invention relates to electrical engineering and can be used to build stabilized sources of electrical power for electronic equipment.

The goal of avoidance is to increase the stability of the output voltage.

The drawing shows a diagram of a stabilized voltage converter.

The converter contains in series between the input and output pins of the converter choke 1 and diode 2, the power transistor 3 connected by a collector to the common point of chokes 1 and diode 2, and the emitter to the common bus, output capacitor 4, reverse diode 5, comparison node 6, the input is connected to the output pins, and the output through the control node 7 is connected to the control input of the power transistor 3, the control node 7 together with the power transistor 3 forms a controlled multivibrator and includes the first 8 and second 9 Orae, the capacitor 10 and the first 11 and second 12 resistors connected in parallel transitions base - collector of the first 8 and second 9 transistors, respectively. The base of the transistor 8 is the input of the control node 7 and is connected to the output transistor of the reference node, the connection point of the emitter of the transistor 8 and the collector of the transistor 9 is the output of the control node 7 and is connected to the base of the power transistor 3.

The Converter operates as follows.

When the supply voltage is turned on, when the voltage at the output of the converter is low, the output of the comparison node 6 appears voltage that opens the transistor 8, the transistor 9 is in active mode, the power transistor 3 opens and a current flows through the winding of the drossel 1 causes an increase in the magnetic flux in its magnetic conductor. When the collector current of the forcible transistor 3 reaches its maximum value, the increase in the magnetic flux in the inductor stops c, the polarity of the voltage on its winding will change to reverse, and the positive voltage through the capacitor Yu will flow to the base

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transistor 9, which opens completely, causing an avalanche-like process of locking transistor 3. At the moment of pause, when transistor 3 is closed, a positive voltage pulse opens diode 2 and the rectified voltage charges the output capacitor 4. At the next cycle, when transistor 9 closes, the transistor 3 opens, and the diode 2 closes, the capacitor 4 discharges to the load, ensuring the flow of direct current in the load circuit.

When the output voltage value changes, the output signal of the comparison node 6 changes the collector-emitter junction resistance of transistor 8, thereby causing a change in the base current of transistor 3 and this is due to -. changes the time for growing the magnet southwest of the flow drossel 1 and the energy stored in it, thus achieving stabilization of the output voltage of the converter.

The output voltage in the converter is stabilized by a knotted: 7 control voltage, which produces such a control voltage that helps turn on and off the power transistor 3 with a certain frequency and duration, ensuring the stability of the output voltage with a given accuracy.

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Claims (1)

Invention Formula A stabilized DC-voltage converter containing a choke and a diode connected in series between the input and output pins, a power transistor connected between the common point of the throttle and the diode and the common bus, an output capacitor, a reference node, an input connected to the output pins, and an output through the node control to the control input of the power transistor, characterized in that, in order to increase the stability of the output voltage, the control node is designed as a control modulator on the first and second transistors, the first, the second resistor and the capacitor, with the first and second transistors transitions collector-emitter connected in series between the input pins, the base per314675504 the transistor is the input, is connected via a capacitor to the base and the emitter connection point of the first second transistor, the transitions of the collector transistor and the second collector — the torus — the base of the first and second transistor — the output of the control unit, the resistors are bridged first and second , the power transistor collector eye resistors, respectively.