RU1820944C - Constant voltage pulse stabilizer - Google Patents

Abstract

Usage: in power systems of automation devices and computer technology. The inventive device contains a control transistor 1, an LC filter 2, a relay element (RE) 5, a constant-current amplifier (DCT) 6, a constant voltage source 17, two diode-resistive circuits 18 and 21, a synchronizing generator 16. With the phenomenon at the output of the low voltage potential converter 6, which is established by a short circuit at the output of the stabilizer, the RE 5 turns into an amplifier stage connected in series with the voltage amplifier 6. The control transistor 1 is thus closed so that an allowable current flows through it short-circuit, which does not result in rapid overheating of the regulating transistor and, consequently, to failure of the stabilizer. Thus, the device provides protection for the control transistor 1 during a short-circuit at the output of the stabilizer. 6 C.p. f-ls, 5 ill.

Description

Figure 1

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ABOUT

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The invention relates to electrical engineering, in particular to secondary power sources, and can be used in power systems of automation devices and computer equipment.

The purpose of the invention is to increase the reliability of the stabilizer by limiting and decreasing the current through a regulating transistor.

In FIG. 1 is a block diagram of a device with a first additional constant voltage source ti with an improved relay element; Fig. 2 is a diagram similar to that of Fig. 1, but with an additional second constant voltage source, an adder and an additional transistor; Fig. 3 is a diagram similar to the circuit in Fig. 1, but with an additional rectangular pulse generator and a transistor switch, Fig. 4 is a circuit similar to the circuit in Fig. 1, the nose of one of the possible circuits for performing the first additional source, 5 is one of the possible circuits of an improved relay element.

Pulse constant voltage stabilizer (figure 1) contains a control transistor 1, the emitter-collector transition of which is connected in series with the LC filter 2, load 3 and a constant unstabilized voltage source 4, the base of the control transistor 1 is connected to the output of the relay element 5 the input of which is connected to the output of the DC amplifier 6, a capacitor 7 of the LC filter 2, a reference voltage source 8 made of a ballast resistor 9 and a zener diode 10, and a resistor delta are connected in parallel to the load 3 voltage 11, made on two resistors 12, 13 and one variable 14 connected in series 14, the outputs of the reference voltage source 8 and the resistor voltage divider 11 are connected to the first and second inputs of the DC amplifier 6, a switching diode 15. connected between the connection point of the control transistor 1 and the inductance of the LC filter 2 and the common stabilizer bus, a synchronization generator 16 connected to the input of the relay element 5. The device also contains a first additional source for a constant voltage 17, the output voltage of which does not exceed the voltage of the reference voltage source 8 and connected through a circuit 18 consisting of a diode 19 and a resistor 20, to the input of a DC amplifier 6 connected to a resistor voltage divider 11 and a circuit 21 consisting of a series-connected diode 22 and a variable resistor 23 and connected in parallel with a ballast resistor 9 of a reference voltage source 8.

The pulse stabilizer shown in FIG. 2 also contains a transistor 24, the collector-emitter junction of which is connected in parallel with the zener diode 10 of the reference voltage source 8. The second additional constant voltage source 25 having an opposite polarity with respect to the main constant source 4 unstabilized voltage and starting

5 simultaneous resistor combiner

26 to two inputs formed by resistors

27 and 28, the inputs of which are connected to the output of the stabilizer and the output of the second additional source 25. and the output

0 of the adder 26 is connected to the base of the transistor 24, parallel to the junction base of the zmitger which includes an inertial element 29 made, for example, on a capacitor. Pulsed constant stabilizer

5 of the voltage shown in FIG. 3, in addition to the elements shown in FIG. 1 also contains a transistor switch 30, a rectangular pulse generator 31 having adjustable pulse durations and pauses between pulses, a circuit 32. consisting of a series resistor 33 and a zener diode 34, a first additional resistor 35 through which the base of the regulating transistor 1 connected to

5 by a collector of a transistor switch 30, the emitter of which is connected to a common bus, and its base is connected simultaneously with the output of the stabilizer through circuit 32 and with the output of the square-wave generator 31, output

0, the power of which is connected to the input of the stabilizer through the second additional resistor 36 and to the collector of the transistor switch 30 through the diode 37.

Pulsed constant stabilizer

5 voltage shown in Fig. 4. in addition to the elements shown in figure 1, contains a resistor 38 and a zener diode 39, forming a constant voltage source 17 - one of the possible options

0 of the specified source.

Figure 5 presents one of the possible technical solutions of the relay element 5. consisting of a Schmitt trigger 40, formed by transistors 41, 42, resistors 43, 44, 45, 46, a capacitor 47 and a diode 48, connected in the opposite direction parallel to the base transition the emitter of transistor 42, transistor switch 49, connected by an input to the output of a Schmitt trigger 40 through a resistor 50, and by an output to

the base-emitter junction of the regulating transistor 1 through a circuit 51. composed of a parallel-connected resistor 52 and a capacitor 53, a parametric stabilizer 54 formed by a ballast resistor 55 and a zener diode 56, to which the Schmitt trigger power leads are connected.

The device shown in figure 1, operates as follows.

When i) the source A of the unstabilized voltage is turned on, a constant voltage Uex is applied to the input of the stabilizer. The voltage at the output of the Ueiix stabilizer is zero. The regulating transistor 1 is opened by a pulse coming from the output of the relay element 5. The voltage at the input of the filter 2 jumps up almost to the value of the input voltage UBx (minus the voltage drop across the regulating transistor 1) and the voltage at the output of Pvy starts to increase. At the time when the voltage at the output of the stabilizer reaches the upper threshold of the relay element 5, the relay element 5 is activated, and the control transistor 1 closes / After closing the control transistor 1, the switching diode 15 opens due to the self-induction EMC filter 2, the output voltage first increases due to the energy stored in the throttle of filter 2, and then begins to decrease. At the time when the voltage at the output of 11Vy decreases to the lower threshold of the relay element 5, the latter opens the control transistor 1. The voltage at the output of the output of the stabilizer first decreases, and then, when the current in the winding of the throttle filter 2 becomes equal to the load current, again increases to the upper threshold of the relay element 5. At the time when this threshold is reached, the relay element 5 closes the control transistor 1. Thus, then the processes are repeated. As the input voltage Uex changes, the slew rate of the output voltage changes, and the average value is maintained constant with a certain degree of accuracy. This degree of accuracy is set by the source of the reference voltage 8. by a resistor voltage divider 11 and a DC amplifier 6. The voltage divider 11 controls the output voltage 11out, a part of which is taken from the slider of the variable resistor 14 of the voltage divider 11, is compared with the reference voltage voltage Uon, taken from the zener diode 10 of the reference voltage source 8. Comparison is carried out using a DC amplifier 6 - at its input, the difference signal is amplified by this amplifier and goes to the input of the relay element and 5. If the input relay element 5 or to the input of the DC amplifier used to submit periodic external impact from timing generator 16 (shown

0 with dashed lines), under certain conditions, the external periodic action imposes its frequency on the stabilizer and suppresses possible self-oscillations. The higher the frequency of the forced oscillations at the same parameters of the LC filter 2, the smaller the amplitude of the output voltage ripples. The upper limit of the switching frequency is determined by the frequency properties of the regulating

0 transistor 1, switching diode 15 and capacitor 7 of the LC filter 2. In this case, the relay stabilizer operates in the mode of pulse-width modulation. This is how processes occur in the stabilizer when the load resistance 3 corresponds to the nominal or maximum permissible value. In emergency mode, when the load resistance is much less than the maximum

0 value, for example, during a rotary circuit, the output voltage 1) output decreases sharply and becomes lower than the lower threshold of the relay element 5, the latter opens the control transistor 1 and maintains it in this state. The choke of filter 2 quickly enters saturation, and almost the entire input voltage Uex is applied to the open regulating transistor 1, through which a current begins to flow, limited only by the internal resistance of the open regulating transistor 1. Obviously, this mode does not correspond to the safe operation area of the regulating transistor 1, and this leads to its quick failure 5 even with a short rotary circuit at the output of the stabilizer. In analogue stabilizers, protection against short-term short-circuit is sometimes built on the principle of forming a new reference voltage, which is much lower than the previous one, and the output voltage is monitored with respect to the new reference voltage. This is achieved limitation

5 of the current through the control transistor, and the power released from it decreases. A similar principle can be used in key stabilizers. To do this, the following conditions must be met: to form a new reference voltage, significantly less than the previous one, switch the relay element to the amplifier stage mode and provide a constant current amplifier mode such that a low potential is established at its output during a short circuit at the output of the stabilizer. In this case, the regulating transistor will have a large internal resistance, this will limit the current through it, and the failure of the stabilizer will not happen so quickly.

. In the embodiment of FIG. 1 technical solution, a new reference voltage is generated automatically when the output of the stabilizer is shorted - it becomes equal to zero in the case of the implementation of DC amplifier 6 according to the scheme with differential input. In the case when the DC amplifier 6 is made on a single transistor and the zener diode 10 of the reference voltage source 8 is included in the emitter of this transistor, a new reference voltage is generated using circuit 21, a diode 22 and a variable resistor 23 of which are connected in parallel with the source ballast 9. reference voltage 8. This circuit is indicated by a dashed line. Using an additional DC source 17 connected to the input of the DC amplifier 6 connected to the resistor voltage divider 11 through a circuit 18 consisting of a series-connected diode 19 and resistor 20, low potential is established at the output of the DC amplifier current 6 with a short circuit at the output of the stabilizer. Resistor 20 is necessary when the DC amplifier 6 is made on a single transistor. Diode 19 is a decoupling element, eliminating the influence of an additional DC source 17 on the operation of the stabilizer during normal operation. When a low potential is established at the output of the DC amplifier 6, the relay element 5 must turn off the control transistor 1, since this state of the DC amplifier 6 during normal operation of the stabilizer corresponds to exceeding the upper permissible limit of the output voltage. The switching of the relay element 5 to the amplifier stage is a necessary condition, since it provides monitoring of the voltage source of the reference voltage 8 at the output of the voltage regulator. Otherwise, the stabilizer could not be turned on, for example, under capacitive load. Variable resistor 23 can be controlled within certain limits of the short circuit current of the stabilizer. The voltage stabilizer made according to this scheme, with a short

circuit works as follows. When a short circuit occurs at the output of the stabilizer, the reference voltage of the reference voltage source 8 becomes much lower than its previous value,

0 an additional constant voltage source 17 sets the output of the constant current amplifier 6 low potential, putting the relay element 5 in the mode of the amplifier stage, included

5 in series with the DC amplifier 6. This causes the regulating transistor 1 to close so that a permissible short circuit current of the stabilizer flows through it, which does not lead to rapid overheating of the regulating transistor 1 and, consequently, to the failure of the stabilizer. Thus, this circuit protects the regulating transistor 1 with a short

5 circuit at the output of the stabilizer. In the long-term short-circuit mode of the stabilizer, it does not protect it from failure, especially when the DC amplifier 6 is made on a single transistor.

0 This disadvantage is eliminated in the circuit shown in Fig. 2. Here, the reference voltage of the reference voltage source 8, when overcurrented or shorted at the output of the stabilizer, becomes practically zero, since it is equal only to the voltage drop on the transistor switch 24, which is in a saturated state. The device operates as follows. Using adder 26, two different-polarity voltages are summed: the output voltage of the stabilizer 11out. and voltage 11up. 2. a second additional constant voltage source 25. The resistances of the resistors 27 and 28 of the resistor adder 26 are selected such that during normal operation of the stabilizer, the potential based on the transistor 24 helps to lock this transistor. When current overload or short circuit occurs at the output of the stabilizer, the potential at the base of transistor 2a changes and becomes such that transistor 24 opens slightly, the reference voltage U0n. decreases

5, an avalanche-like process develops, as a result of which the transistor 24 is fully open and the output voltage is higher. decreases to almost zero and remains in this state as long as the DC source 4 and the second

an additional constant voltage source 25. since the latter keeps the transistor 24 open. In the case where the constant unstabilized constant voltage source A and the second additional constant voltage source 25 are turned on at the same time, the inclusion of a stabilizer is hardly possible, since the voltage is Kdop. 2 at the output of the second additional source 25 starts earlier than the voltage at the output of the stabilizer due to the presence of the capacitance 7 in the filter 2 and. therefore, the reference voltage will be zero. Accordingly, the output voltage of the stabilizer will be close to zero. To avoid this, an inertial element 29 is introduced into the circuit, which delays the inclusion of transistor 24 so that, in the absence of current overload or short circuit at the output of the stabilizer, the output voltage reaches its rated value. The inertial element 29 can be performed on the capacitor.

A relative disadvantage of this device is that after the protection has been activated, it is necessary to turn it off and on again to turn on the stabilizer, i.e. there is no automatic restart. This disadvantage is eliminated in the device of FIG. Here, the base current of the control transistor 1 flows through the first additional resistor 35 and the transistor switch 30 connected in series, the base of which is connected directly to the rectangular pulse generator 31 and to the output of the stabilizer through a circuit 32 consisting of a series-connected resistor 33 and a zener diode 34. The resistor 33 and the zener diode 34 are selected such that during normal operation of the stabilizer, the current flowing through the resistor 33 is sufficient to keep the transistor switch 30 in a saturated state. Zener diode 34 is also selected by voltage. It should be less than the rated value of the output voltage of the stabilizer. The device operates as follows. After turning on the unstabilized voltage source 4, the voltage is supplied to the control transistor 1 and to the square wave generator 31. At the output of the stabilizer, the voltage does not appear until a current or voltage pulse is generated at the output of the square pulse generator 31 including a transistor switch 30 for a predetermined time. The duration of this pulse is selected so that at the permissible maximum load, the rated voltage is established at the output of the stabilizer. This allows, in the future, 5 to maintain the open state of the transistor switch 30 through circuit 32. If the output of the stabilizer is short-circuited or overloaded, the stabilizer will not turn on, since after the end of the pulse signal of the generator of rectangular pulses 31, the transistor switch 30 will close until the next impulse arrives. The time between them is chosen so as to ensure

5, the operation of the control transistor 1 is safe, although the current through it is limited, but the instantaneous power can be large. So that the rectangular pulse generator 31 does not affect the operation of the transistor switch

0 30 during normal operation of the stabilizer, it must be turned off and automatically turned on if an overload or short circuit occurs at the output of the stabilizer. One possible solution is shown in FIG.

5 Here, a square-wave generator 31 is connected via a power bus to an unstabilized voltage source 4 through a resistor 36 and to a collector of a transistor switch 30 through a diode 37 (shown with a dotted line). When the transistor switch 30 is open, the supply voltage is removed from the square-wave generator. Otherwise, the operation of the circuit does not differ from that described above. Similar quality can be obtained in

5 of the circuit shown in Fig. 2, introducing a pulse generator of rectangular pulses with adjustable pulse durations and pauses between them and connecting its output to the base of the transistor 24, shunting the zener diode 10 of the reference voltage source 8.

Figure 4 shows a device in which one of the possible technical implementations of the first additional constant voltage source 17 is presented in the form of a parametric stabilizer made on a ballast resistor 38 and a zener diode 39 and connected to the output of an unstabilized voltage source 4. Stabilization voltage the zener diode 39 is selected so that it does not exceed 5 times the stabilization voltage of the zener diode 10 of the reference voltage 8 for all technological variations. so that during normal operation of the stabilizer, the first additional source 17 does not affect the operation of the stabilizer.

Fig. 5 shows one of the possible circuits for implementing the relay element 5, which allows under certain conditions to translate the relay element into an analog amplifier circuit.

This element works in normal mode, like all known relay element circuits based on Schmitt triggers. When a signal is generated at the output of the DC amplifier 6 above the upper threshold of the Schmitt trigger, the transistor 42 opens and the transistor 41 closes in a jerky manner, the transistor switch 49 closes, and the current flows to the base of the control transistor 1, which opens to saturation. When a signal is generated at the output of the DC amplifier 6 below the lower threshold of the Schmitt trigger 40, the reverse process occurs - the transistor 42 closes, and the transistors 41 and 49 open abruptly, closing the regulating transistor 1. Diode 48 in both of these cases does not affect to the operation of the relay element. A feature of the operation of this relay element is manifested in an emergency when a short circuit or overload condition occurs at the output of the stabilizer, in which a low potential is generated at the output of the DC amplifier 6 and the reference voltage changes. In this case, thanks to the diode 48 and the parametric stabilizer 54, the Schmitt trigger 40 is converted into a conventional amplifier stage,. since the diode 48 contributes to the fact that the emitter current of the transistor 41 flows through it and the output of the DC amplifier 6, that is, the transistors 41 and 49, goes into analog mode, and the pulse stabilizer turns into analog, which tracks a new reference at the output voltage The circuit 51, consisting of a resistor 52 and a capacitor 53, allows to improve the dynamic characteristics of the relay element 5, providing an active locking mode of the control transistor 1.

,, Using the proposed technical solution improves the reliability of pulsed DC stabilizers. Protect the control transistor and in case of a short circuit or overcurrent at the output of the stabilizer, turn it off completely or, if necessary, ensure automatic restart after tripping.

Claims (4)

SUMMARY OF THE INVENTION 1. A pulsed constant current regulator comprising serially connected between the input and the output terminals are a regulating transistor and an LC filter choke, a capacitor of which is connected between the output terminal and the common bus, a switching diode connected between the connection point of the control transistor and the LC filter interconnect and the common bus, a relay element connected by an output to the control input of the control transistor reference voltage source included 5 between the output terminal and the common bus and made on a series-connected first ballast resistor and a zener diode, a resistive voltage divider connected between the output 0 output and a common bus and made on two constant and one variable resistors connected in series with a constant current body, the first and second inputs of which are connected to the outputs of the reference voltage source and the resistive voltage divider, respectively, and the output is connected to the input of the relay element, to which is also connected a synchronizing generator, characterized in that 0 that, in order to increase reliability by limiting the current through the control transistor, a constant voltage source is introduced into it, the output voltage of which does not exceed the voltage of the source 5 nmA of the reference voltage, the first and second circuits, consisting of the first diodes connected in series and a resistor and a second diode and a variable resistor, with the first circuit included 0 between, the output of the constant voltage source and the second input of the DC amplifier, and the second circuit is connected in parallel with the first ballast resistor, while the relay element is made with 5 with the possibility of providing operation in the mode of an amplifier stage connected in series with a constant current amplifier when a low potential is established at the output of the constant current amplifier. 0 2. The stabilizer according to claim 1, with the aim that, in order to increase reliability by providing protection for the regulating transistor during long-term short circuit at the output of the stabilizer by limiting and subsequently decreasing to almost zero current through regulating transistor, an additional transistor, a resistive adder for two inputs, an inertial element and an additional constant voltage source having the opposite voltage polarity with respect to the source are unstabilized a constant voltage connected between the input terminal and the common bus, and turning on simultaneously with it, the additional transistor connected in parallel with the first zener diode, its base connected to the output of the resistive adder, the first and second inputs of which are connected respectively to the output terminal and to output of an additional constant voltage source, and the inertial element is connected between the base and the emitter of the additional transistor. 3. The stabilizer according to claim 2, with l and h.a., with the fact that the inertial element is made on the capacitor. 4. The stabilizer according to claim 2 or claim 3, which requires that, in order to ensure automatic restart after a specified time after the protection is activated by periodically closing the additional transistor, a rectangular pulse generator with adjustable pulse durations and pauses between pulses, and the output of the rectangular pulse generator is connected to the base of an additional transistor. 6. The stabilizer according to claim 1, with the exception that, in order to increase reliability by providing protection for the regulating transistor during prolonged overload or short circuit at the output of the stabilizer by limiting and then decreasing to zero current through the control transistor, as well as to ensure automatic restart after a specified time after the protection trips by periodically opening the control transistor for a specified time, the first transistor switch, a generator, is introduced into it p rectangular pulses with adjustable pulse durations E and pause between pulses, an additional circuit consisting of a third resistor and an additional zener diode connected in series, a fourth and fifth resistor and a third diode, and the base of the control transistor through the fourth resistor connected to the collector of the first transistor switch, the emitter of which is connected to the common bus, and the base is connected simultaneously with an output terminal through an additional circuit and with the output of a rectangular pulse generator, the power output of which is connected to the input terminal through a solid resistor and to the collector a first transistor switch via a third diode. 6. The stabilizer according to claims 1-4 or 5, wherein the constant voltage source is made in the form of a parametric stabilizer on a second ballast resistor and a zener diode connected in series, the free terminals of which are connected respectively to the input output and the common bus, while the stabilization voltage of the second zener diode for all technological variations does not exceed the stabilization voltage of the first zener diode. 7. The stabilizer according to claims 1-5 or 6. The condition is that the relay element is made on a Schmitt trigger, a second transistor switch and an additional parametric stabilizer connected between the input terminal and the common bus and made in the form of series-connected third zener diode and ballast, and the control input of the second transistor switch is connected to the output of the Schmitt trigger, and its output is used as the output of the relay element parallel to the control input of the input transistor of the trigger Ш Ithai used as an input element of the relay is turned in the opposite direction inputted fourth diode, a Schmitt trigger terminals coupled with a third Zener diode. "M IS) J5 0 I 1718 5 -G5-W "Ft "4 -"4 $ HЈ g I r№l