SU1198501A1 - D.c.voltage stabilizer with overload protection - Google Patents

Abstract

CONSTANT STABILIZER. VOLTAGE WITH OVERLOAD PROTECTION, containing a regulative element in the power bus in series, and a current sensor, a protective transistor whose collector is connected to the input circuit of the regulating element and to the output of the test feedback amplifier node, whose input is connected to the output bus relative to the common bus the output to which the emitter of the transistor is connected, the base of which through. successively connected the first and second resistors are connected to the output terminal of the regulating element, and the combined output these resistors are connected to one of the terminals of the third resistor, the threshold element connected in parallel to the current sensor, the waiting multivibrator, the output of which is connected to the control input of the key, the fourth resistor, the capacitor, characterized in that, for the sake of reliability, an I element is introduced into it and an additional standby multivibrator, with the other output of the third resistor being connected via a capacitor to the high-voltage output, the output of the threshold element is connected to one of the inputs of the element I, the output of which is connected to (L in th additional monostable multivibrator, whose output is connected to another input of the AND and the input of a monostable multivibrator, a switch is connected between the common bus and via a fourth resistor - vshodami combined first and second resistors. . from 00 SP

Description

one

The invention relates to electrical engineering and can be used in power supply devices for automation units, computing equipment and communication facilities with a pulsed nature of the load.

The purpose of the invention is to increase reliability.

The drawing shows a functional diagram of an art; DC voltage absorber —c overload protection ;;;

The device contains a regulating element 11; {ent., 1 and a current sensor 2, a protective transistor 3, the collector of which is connected to the output of the feedback measuring and amplifying unit 4 and the control input of the regulating element 1, the base sequentially connected first and the second resistors 5 and 6 are connected to the output of the regulating element 1, the combined terminals of these resistors are connected via a series of third resistor 7 and a capacitor 8 to the emitter of the switching transistor 3 and the output & the house, and through the fourth resistor 9 and the key 10 - with the common busj parallel to the current sensor 2 is turned on the threshold element 11, the output of which is connected to the first input of the element AND 12 whose output through the series-connected additional and main pending multivibrators 13 and 14 is connected to the control input of the key 10, the second input element And is connected to the output of the additional standby multivibrator 13.

The device works as follows.

In the initial state, the outputs of the waiting multivibrators 13 and 14 are voltage 1, the key 10 is closed. If the load current does not exceed the nominal operation threshold of the protection, the voltage drop on the sensor 2 does not have enough current to open the protection transistor 3 and it does not affect the operation of the voltage regulator. With a pulsed increase in the load current, the voltage drop across the current sensor 2 increases abruptly, which through resistors 5 and 6 goes to the sam iTHoro base of transistor 3, however, at the first moment of the pulse, it increases

In this case, the opening current of the protective transistor 3 does not occur, since the voltage applied to its base is shunted by the resistor 7 through the charging capacitor 8. Simultaneously, the threshold element 11 triggers, the trigger threshold of which is chosen greater than the nominal protection threshold, but less than the required

pulsed load current. Signal. at its output, changes from 1 to. This signal through the element And 12 is fed to the input

5 waiting multivibrator 13, which begins to produce a negative impulse of duration T arriving at the second input of the element 12, and thus preventing the repeated activation of the multivibrator 13 before the end of the impulse generated by it. The leading edge of the pulse from the output of the waiting multivibrator 13 is triggered by the waiting multivibrator 14, which

generates a pulse of duration T, during which the salute 10 opens, as a result of which the resistor 9 is connected to the common

Q bus. According to the circuit: resistor 5, resistor 9 begins to flow a current, which creates a blocking voltage relative to the protective transistor, which leads to a sharp increase in the threshold of operation of the protection above the nominal. Due to this, during the time T is provided, the load is supplied with a pulsed current, which significantly exceeds the nominal protection threshold. At the end of the pulse generated by the waiting multivibrator 14, the key 10 is closed and thereby sets the nominal protection response threshold. If the load current has not decreased by this time, then its limit will be limited to the nominal value of the protection response threshold. Re-supplying a pulsed load current is possible at the end of a pulse, BbipLa6aTMBae, with a standby multivibrator 13. For normal operation of the device, the duration Tj of the pulse produced by the standby multivibrator 14,

5 should be 30-50% more than the time of the load current pulse, and the duration T of the pulse produced by the waiting multivibrator 13 should 3 .1 be 20-30% less. The gap between the pulses of the load current. Thus, it is provided for a time Tj. supplying the load with current, which significantly exceeds the nominal threshold of the protection system by increasing the threshold of protection operation for a short time. By 14. A torus current supply to the load is possible only after time T. In the proposed device, the increased reliability of operation is achieved due to the fact that the possibility of the control transistor failing due to its overheating with an increase in the repetition frequency of the load current pulses over the calculated one is excluded.

Claims (1)

DC VOLTAGE STABILIZER WITH OVERLOAD PROTECTION, containing a control _element.i current sensor and a current sensor, protective: a transistor, the collector of which is connected to the input-circuit of the regulating element and to the output of the feedback measuring amplifier, the input of which relative to the common bus is connected to the output the output * to which the emitter of the transistor is connected, the base of which is connected through the series-connected first and second resistors to the output terminal of the control element, and the combined terminals of these resistors are connected to one of the terminals of the third resistor, a threshold element connected in parallel with the current sensor, a waiting multivibrator, the output of which is connected to the key control input, a fourth resistor, a capacitor, characterized in that, in order to increase reliability, an element is introduced into it And an additional standby multivibrator, and the other terminal of the third resistor through the capacitor is connected to the output terminal, the output of the threshold element is connected to one of the inputs of the element And, the output of which is connected with n additional input of a monostable multivibrator, whose output is connected to another input of the AND and the input of a monostable multivibrator, a switch is connected between the common bus and via a fourth resistor - the combined first and second terminals of resistors. . Q "e □ o cn>