SU1506440A1 - Protected power supply system - Google Patents

Abstract

The invention relates to electrical engineering and can be used in power sources of various electronic devices. The purpose of the invention is to reduce the residual current of voltage regulators in the short circuit mode of the load, to protect the matching transistor in the case of separate power supply of the transistors, as well as to extend the functionality by ensuring their sequential operation on the total load. When each stabilizer is operating in a short-circuit mode, the collector-emitter transitions of transistor 18 create an additional shunt effect on the regulating element 4 and the matching transistor 7. The latter is protected by a resistor 19, which forms a voltage at the input of the protection unit that limits its current. The ability of the stabilizers to start when they are switched on in series is provided by the optocoupler 14, which turns off the collector of transistor 18, which increases the triggering threshold of the protection by the amount of voltage drops at the base-emitter junctions of the starting process. 1 il.

Description

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The invention relates to electrical engineering and can be used in power sources of various electronic devices.

The purpose of the invention is to reduce the residual current of the voltage regulator in a short circuit of the load, to protect the matching transistor in the case of a separate power supply, as well as to expand its functionality by ensuring their consistent operation on the common load. The drawing shows a power system diagram with protection for 15 cases of series connection.

Stabilizers 1 and 2 are connected in series and feed the total load 3. Each stabilizer contains a regulating element 4, made according to the scheme of a composite transistor on n transistors and connected by a collector to a positive input terminal, an emitter through a resistive current sensor 5 with an output terminal, one of the terminals an output voltage divider 6, the other output of which is connected to a common Sh, is not a matching transistor 7 connected to an output for connecting a source of power with a collector

with the collector of the first protection, the amplifier 9 of the feedback circuit with the voltage source connected to the common bus by the power output with the output for connecting the source of water, the output output with the base of the matching transistor 7, and the input output with the middle output of the divider 6 output voltage 40 NIN, bias voltage divider 10, the resistor 11 of the first shoulder of which is connected between the emitter of the matching transistor 7 and the base of the first transistor 8 of protection, the resistor 12 of the second shoulder is connected to the common bus, Iodine 13, optocoupler 14, consisting of a photothyristor 15 and an LED 16, limiting the resistor 17, a composite second protection transistor 18 of n-1 transistors, a protective resistor 19. The protective resistor 19 is connected to the emitter of the regulating element 4 and the emitter of the matching transistor 7, the base (the remaining second transistor 18 is connected to the emitter of the first trillion protection 8 trillion, a collector through nept Xi a cathode-anode of the photothyristor l5 i; lm gppish with a collector transis subs. base transistor

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torus 8, and the diode 13 and the led 16 are connected in parallel to the output pins of the stabilizer, and the diode 13 is in the opposite direction, and the led 16 through the resistor 17 in the forward direction.

The stabilizer works as follows.

When connecting, for example, the stabilizer 2 to the power sources, if the stabilizer 2 is loaded on its own load (shown in dotted lines), the transistors 8 and 18 are closed, which contributes to the normal switching on of the stabilizer.

Stable switching is ensured by the fact that the opening of the transistors 8 and 18 of the protection is prevented by the voltage at the base-emitter transitions of the composite transistor 18, which neutralizes the effect of the base-emitter voltage of the transistors in the regulating element 4.

The voltage between the base and the emitter of the transistors 8 and 18 in the normal mode of operation of the stabilizer is equal to the sum of the voltages on the resistor 5, the base-emitter junctions of the transistor 4, resistor 11, divider 10 and is set with resistors 5 and 11 equal to 0.3-0, 4p In, where p - the number of transistors, the input of the hops in the transistor 4, which is sufficient for reliable locking of the transistors 8 and 18 protection. The voltage across the resistor 19 can be neglected due to its smallness.

When an overload occurs at the output of the stabilizer, the current through the resistor 5 increases, which leads to an increase in the voltage between the base and the emitter of the transistors 8 and 18, they open, the output voltage of the stabilizer decreases.

In case of a short circuit at the output of the stabilizer, its residual current is much less, which is facilitated by the use of a composite transistor 18 as a second transistor, (n-1) of open transitions, the collector - whose emitter creates an additional bypassing effect on the regulating element 4 and the matching transistor 7 .

If the voltage Od, the feed source is supplied earlier than the voltage V |, u to the collector of transistor 4, the base-to-emitter transitions of the latter work as directly connected diodes and in the absence of resistor 19 the voltage across resistor 5 drops

insufficient to open the protective transistors 8 and 18 when the current is safe for the matching transistor 7

At the same time, an additional unlocking protective transistors 8 and 18 appear on the resistor 19, and the transistors 8 and 18 open and limit the current through the transistor 7 to an acceptable level.

If you apply the + V voltage

pit then the transistor 4 enters the linear

mode, the emitter current of the matching transistor 7 is sharply reduced, the voltage across the resistor 19 decreases, the protective transistors 8 and 18 are closed and the stabilizer goes to normal operation. Subsequently, the resistor 19 does not affect the operation of the stabilizer, since the base current of the transistor 4 flows through it very small. The optocoupler 14 is not affected by the operation of the stabilizer, since the photo thyristor 15 remains open at both the nominal load and the possible subsequent output overload.

Thus, in the proposed stabilizer, the residual current in the short-circuit mode of the load is reduced and the matching transistor is protected in the case of separate supply of the matching and j power transistors of the regulating element.

The operation of a voltage regulator with overcurrent protection during the series connection of stabilizers 1 and 2 to a total load 3 is as follows.

If, for example, the input supply voltage is + V. and + pol. 1 include earlier input supply voltages., and. , then, the voltage, at the output of the stabilizer 1 appears before the voltage Vg, at the output of the stabilizer 2, while the reverse diode 13 of the stabilizer 2 and the total load start to flow a current that opens the diode 13 and creates at the output of the stabilizer 2 artificial short circuit. In this case, there is no current in the LED circuit 1 6, the phototransistor 15 is locked, the collector-emitter circuit of the transistor 18 does not flow, but the base-emitter junctions of the transistor 18 work as n-1 open, series-connected diodes, providing the emitter

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the transistor 8 with the current sensor 5, the transistor 8 is cut off, but cannot fully close the transistors 7 and 4, since the main shunt effect on them is provided by the transistor 18, which is currently closed at the collector.

In this case, the start is roughened, a residual

sufficient current to close

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diode 13, the latter is closed, the short circuit at the output of the stabilizer 2 is eliminated, the voltage Vg rises to its nominal value, then triggers the photo thyristor 15, providing a duty connection of the collector of the transistor 18 to the collector of the transistor 8, and works as an open diode. If during the operation of stabilizers, an overload or short circuit of the load occurs, then the transistor 18 opens the thyristor (diode) 15 additionally pushes the transistors 7 and 4, providing the minimum residual current through the stabilizers.

Thus, voltage regulators with AC / DCRT overcurrent, connected in series, go to the nominal mode of operation, regardless of the sequence VK. Gyucheni input voltage. .

Claims (1)

Invention Formula Electroplating system with at least two (DC voltage regulator, each of which includes a regulating element, which is a single transistor based on n transistors and connected by a colloctor with input transistor, an emitter through a resistive current sensor - output terminal and one of the outputs of the output voltage divider, the output of which is connected to the common bus, a matching transistor, a collector connected to an output for connecting a source of water, a base to the collector of the first tran protection sensor, a feedback amplifier with a voltage source, connected to a common bus with a power supply terminal with an output for connecting a source of water, a power output terminal with a matching granisistor base, and an input output with an average output voltage divider, and a bias voltage a voltage divider connected between the emitter of the matching transistor and the common bus and the middle of which is connected to the base of the first protection transistor, characterized in that, in order to reduce the residual current, short-circuit protection, protection of the matching transistor in the case of separate power supply of the matching and power transistors of the regulating element, as well as extending the functionality by ensuring their consistent operation on the common load, a diode, an optocoupler consisting of a photothyristor and a LED limiting resistor, the second protection transistor of n-1 transistors and a protective resistor, the protective resistor being connected between the base of the composite transistor of the regulating element rt and the emitter of the matching transistor, the second base-protecting transistor with the emitter, and the collector through the cathode - anode of the photothyristor junction - with the collector of the first protective transistor, the emitter - with the output terminal, and the diode and the LEDs of the optocoupler connected in parallel to the output terminals, respectively, the diode in reverse, the LED through the limiting resistor in the forward direction.