SU1403046A1 - Power source protection device - Google Patents

Abstract

The invention relates to electrical engineering and can be used in power supply devices for electronic equipment. The purpose of the invention is to increase reliability by eliminating false positives of protection and ensuring operability for capacitive loads. When turned on, the threshold node 16 is triggered at a certain output voltage level and connects the photo sensor 20 of the optocoupler 18 to the power source through the thyristor 7, as a result of which the photodetector 21 of the optocoupler 18 turns on the base circuit of the blocking transistor 1, which provides protective properties. 1 il.

Description

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The invention relates to electrical engineering and can be used in power supply devices for electronic equipment.

The purpose of the invention is to increase the reliability of the device by eliminating false alarms of protection and ensuring that the capacitive load is operable.

The drawing shows the basic electrical circuit of the power source protection devices.

The device contains the first blocking I and 2 regulating transistors, the separation diode 3j connected to the output terminal for connecting the load 4, the first current-limiting resistor 5, the first control transistor 6, the capacitor 7, the first current supplying resistor 8, the second current-limiting scrap -, the torus 9, the second control11 transistor fO, the second blocking transistor 11, the second current-setting resistor 12, the voltage divider 13, the resistor. 1D connected to the common bus to which the power source 15 is connected, the threshold node 16, the thyristor 17, the optoelectronic device 18, and the third current limiting resistor 19, while the threshold node 16 is connected to the output / output and the common bus (pa ralle.no load 4), and the output is connected to an abrasive electrode of the thyristor 17, which is connected to the common busbar by the cathode, and to the anode through the light source 20 of the optoelectronic device 18 and the current-limiting resistor 19, connected in series, to the input one. output, photodetector 21 optoelectronic device 18 in a 43, 1vodov connected to the base of transistor locking i, and Drew

This terminal is connected to the cathode of diode 3.

The device works as follows.

When the power source 15 is connected, the regulating transistor 2 opens, because the collector current of the open transistor 10 flows through its base. The blocking transistor 1 is closed because its base circuit is broken by the photoreceiver 21 of the optoelectronic device 18. At the same time, the load 4 begins to leak current . When charging a capacitor shunting the load 4 on

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it establishes the nominal setpoint voltage. This triggers the threshold node 16, issuing a signal to the control electrode of the thyristor 17, which, opening, closes the circuit of the light source 20 of the optoelectronic device 18. The limiting resistor 19 determines the required current through the light source 20 of the optoelectronic device 18, Triggered, the photodetector 21 forms The base circuit of transistor 1 through the current limiting resistor 5 and the control transistor 6. In the working mode, the transistor 11 is closed and the transistor GO is open. The blocking transistor I and transistor 6 are also closed. At: current overload -1pi short circuit in the load 4, the regulating transistor 2 goes out of saturation. This is accompanied by an increase in voltage at the base of the blocking transistor 1, which causes it to be unlocked and, accordingly, additional locking of the regulating transistor 2. As a result of the regenerative process, the regulating transistor 2 is completely locked, disconnecting the load 4 from the power supply 15 of the capacitor 7 while charging through the resistor 9 and the open blocking transistor 1 approximately to the voltage of the power source, Thus, protection is provided in case of current overload or short circuit cania load 4,

When the voltage of the power supply source 15 is increased, the transistor 11 opens and as a result of the regenerative process arising due to the positive feedback through resisti. The 14J is closed by the transistor 10. This is accompanied by the locking of the regulating transistor 2 and the unlocking of the transistor 1, which is maintained in the open state by the current flowing through its base through the resistor 5 and the open transistor 6. When the redirection is removed, the transistor 11 is locked and the transistor 10 is unlocked In this case, the negative potential of the capacitor 7 is applied to the base of the transistor 6. This leads to its locking and, accordingly, feeding the blocking transistor 1 "When the transistor j is locked with stor 1 through the open transition stop 10 and resistor 9 current enters the base

the control transistor 2 and the latter opens, connecting the power supply 1 to the load 4. Thus, the device protects the load from surges in the network.

The introduction of new elements eliminates the possibility of false positives when the device is turned on and ensures its operability in the event that the load is shunt by a capacitor.

Claims (1)

Invention Formula The protection device of the power supply is the NIN, which contains a blocking transistor for controlling the transistor, which is connected to the power bus, the collector of which is connected to the output terminal and the anode of the separation diode, whose cathode is connected to the collector of the first control transistor through the first current-limiting transistor which is connected to the connection point of the capacitor and the first current-setting resistor with the base, another output of the connection to the input terminal, while the collector of the blocking transistor is connected to the base of the transistor transient transistor and through The second current limiting resistor is connected to the collector of the second control transistor, the base of which is connected to the connection point of the collector of the second blocking transistor and the second current supplying resistor, another terminal connected to the input terminal, the base of the second blocking transistor connected to the middle terminal of the voltage divider, one of the terminals which is connected to the input terminal, and another output of the voltage divider, emitter. second blocking and second control transistors through resis The displacement and emitter of the first control transistor for switching to the common bus is characterized in that, in order to increase reliability by eliminating false protection trips and ensuring the operability of i on the capacitive load, a threshold node, a thyristor, an optoelectronic device and a third the current limiting resistor, wherein the threshold node is connected to the output terminal and the common bus, and the output is connected to the control electrode of the thyristor, which is connected to the common bus to the cathode, and the anode through connected In addition, the light emitter of the optoelectronic device and the third current limiting resistor are connected to the input terminal, and the photodetector of the optoelectronic device is connected to the base of the first control transistor by one of the photoelectric receivers, and to the cathode of the separation diode by another terminal.