SU1636835A1 - Impulsive stabilizer of direct voltage - Google Patents

Abstract

The invention relates to electrical engineering and can be used to power various electronic equipment. The aim of the invention is to reduce the ripple level of the output voltage by increasing the maximum switching frequency. The goal is achieved by the action of negative feedback (OOS) s created. 5 3 .1в О «e

Description

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A current of capacitor 19 discharge. OOS ensures that the saturation level of the key transistor 1 is maintained. At the same time, the switch-off time is prevented from increasing. The invention relates to electrical engineering and can be used mainly for powering general-purpose radioelectronic equipment, in particular for powering computer units.

The purpose of the invention is to reduce the ripple level of the output voltage by increasing the maximum switching frequency.

FIG. Figure 1 shows the basic electric circuit of a DC voltage regulator; in fig. 2 - time diagrams of voltages, explaining the principle of its operation.

A DC switching voltage regulator (Fig. 1) contains a key transistor 1 01 01, Ophilter 2 comprising Drossel 3 with a main 4 and an additional 5 windings, a return diode 6 and a capacitor 1, There are also a voltage divider 8, comparator 9, source 10 of the reference voltage, the first resistor 11 and the first capacitor 12.

In this case, the collector and the emitter of transistor 1 are connected respectively to the input terminal and to the input of the DLC filter 2, i.e. to the cathode of diode 6, to the output of the filter i.e. parallel to the capacitor 7), connected to the output terminal, is connected the input of the voltage divider 8, the output of which is connected to the first input of the comparator 9, to the second input of which the source 10 of the reference voltage is connected. One output winding 5 droplets 3 is connected to the base of the key transistor 1.

In addition, the stabilizer contains four diodes 13–16, a second 17 and a third 13 resistors, a second capacitor 19, and a differentiating chain 20. In this case, the second terminal of the winding 5 is connected to the emitter of the key transistor 1. The output of the comparator 9 is through a diode 13, included in conductively, connected to the input of the differentiating chain 20, which is connected via a resistor 11 to a common bus. Chain exit

the first transistor I, which allows to increase the maximum frequency of its switching and, as a result, to reduce the level of the output voltage ripple. 2 Il.

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20 through the capacitor 12 is connected to the base of the key transistor 1 and to the cathode of the diode 14, the anode of which is connected to the emitter of the key transistor 1, to the base of which the anode of the diode 15 is connected. The cathode of the latter through a resistor 17 is connected to a common bus and through the capacitor 19 is connected to the anode of the diode 16, which through a resistor 18 is connected to the tap of the main winding 4 droplets 3. In this case, the cathode of the diode 16 is connected to the collector of the key transistor 1, and the windings 4 and 5 of the chokes 3 are connected according to.

A switching voltage regulator (Fig. 1) operates as follows.

In the initial state at the moment of switching on the primary power source, the capacitor 7 was not yet charged, and the output voltage of the stabilizer, equal to the voltage Е-, on the capacitor 7, is still zero (Fig. 2a).

8 of these conditions at the output of the comparator

9po represents the pulse Eg of the voltage of the logical unit, which through diode 13- is fed to the input of the differentiating chain 20 (Fig. 2b). A short positive pulse EgQ appears at the output of the chain 20, which is obtained by differentiating the pulse E «j (Fig. 2c), the pulse Eg arrives at the base of transistor 1 through a capacitor 12, the transistor is unlocked through both the front winding and the main winding 4 throttles 3, the charge of capacitor 7 begins. Diode 6 is locked. The capacitor 19 is charged with the voltage that exists at the tap of the winding 4. The charging current of the capacitor 19 of the positive polarity flows through the circuit: the tap of the coil 4 - resistor 18 - capacitor F9 - resistor 17 - capacitor 7. Diodes 14-16 are locked .

On the winding 5, a voltage G is created, which is supplied to the base of the transistor 1 and holds it in the open state after the termination of the positive pulse u. v ". ot d), Under the action of the voltage Ey, a current I is generated which flows through the circuit: the left winding pin 5 is the base-emitter gap of the key transistor 1, the right winding pin 5e Voltage E between the collector and the emitter of the open transistor 1 under the action of a voltage, Eg decreases (Fig. 2d). As soon as the voltage E becomes lower than the voltage E (- D ° of which the capacitor 19 was previously charged, the diodes 14-16 are unlocked. As a result, the capacitor 19 begins to discharge, and the discharge current flows through the circuit: 19 - diode 16 - collector-emitter gap of open transistor 1 - diode 14, shunted by winding 5 - diode 15 - bottom plate of capacitor 19 (Fig. 2e), Part of current 1 | о flows through winding 5 and creates a drop on it wiring attached to the gap emitter-base of the key transistor in such a way that the current decreases. The current 1 is thus the greater, the smaller the value of the saturation resistance of transistor 1, i.e. the greater the degree of saturation.

Thus, a 1-bit capacitor current, by reducing the magnitude of the current |, creates a negative feedback. Its action maintains the constant degree of saturation of transistor 1, for example, when ambient temperature fluctuates and / or amplitude variations of Ey on the base. This prevents an increase in the turn-off time of transistor 1, for example, when the ambient temperature rises.

At the moment when the output voltage E reaches the specified nominal value EIOM, the voltage at the output of divider 8, proportional to E7, becomes equal to the reference voltage of source 10. At this moment, negative voltage difference Eg is formed at the output of comparator 9, after differentiation in circuit 20 at its output, a negative pulse Ego appears, with which transistor 1 is forcibly locked (Fig. 2c, e). Under the action of the EMF of self-induction, arising in the inductance of the winding 4, is unlocked

E (Fig. 2c, od 6, and the energy from the indicated induct-diode 6 in the end 10

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This is transmitted through the sensor 7.

Achieved by the cumulative effect of negative feedback on a negative pulse Eg0, the decrease in the turn-off time of transistor 1 makes it possible to increase the maximum switching frequency when working with large load currents. As a result, the level of pulsations is reduced.

Claims (1)

Invention Formula A DC pulse voltage regulator containing a key transistor whose collector is connected to the input terminal and an emitter to the input of a DLC-fmlter whose output is connected to the output output, a voltage divider connected between the output output and the common bus whose output is connected with one of the inputs of the comparator, the other input of which is connected to the source of the reference voltage, the first resistor and the first capacitor, and the filter 0 throttle is double-wound with the main 30 and additional windings, with the additional winding being connected to the base of the key transistor by one terminal, and the main winding is connected between the input and output 01 of the C-filter1, which, in order to reduce the output voltage ripple, by increasing the maximum switching frequency, He introduced four diode, the second d0 and the third resistors, the second capacitor, as well as the differentiating chain, and the main winding of the DLC filter throttle is equipped with a tap, the second output of the additional winding 45 throttle filter 01C is connected to the emitter of the key transistor, the output of the comparator through the first diode connected in the conducting direction is connected to the input of the differentiating 50 chains and through the first resistor to the common bus, the output of the differentiating chain through the first capacitor is connected to the base of the key transistor and to the cathode of the second diode, the anode is connected to the emitter of the key transistor to the base of which the anode of the third diode is connected with a common tire and cher z second kondensa35 diode 6 in con five 0 five This is transmitted through the sensor 7. Achieved by the cumulative effect of negative feedback on a negative pulse Eg0, the decrease in the turn-off time of transistor 1 makes it possible to increase the maximum switching frequency when working with large load currents. As a result, the level of pulsations is reduced. Invention Formula A DC pulse voltage regulator containing a key transistor whose collector is connected to the input terminal and an emitter to the input of a DLC-fmlter whose output is connected to the output output, a voltage divider connected between the output output and the common bus whose output is connected with one of the inputs of the comparator, the other input of which is connected to the source of the reference voltage, the first resistor and the first capacitor, and the filter 0 throttle is double-wound with the main 0 and additional windings, with the additional winding being connected to the base of the key transistor by one terminal, and the main winding is connected between the input and output 01 of the C-filter1, which, in order to reduce the output voltage ripple level, by increasing the maximum switching frequency, He introduced four diode, the second 0 and the third resistors, the second capacitor, as well as the differentiating chain, and the main winding of the DLC filter Dros-filter is equipped with a tap, while the second output of the additional winding 5 throttle filter 01C connected to the emitter of the key transistor, the output of the comparator through the first diode connected in the conducting direction is connected to the input of the differentiating 0 chain and through the first resistor to the common bus, the output of the differentiating chain through the first capacitor is connected to the base of the key transistor and to the cathode of the second diode, the anode is connected to the emitter of the key transistor to the base of which the anode of the third diode is connected with shared bus and ches z second condensation5 lbr is connected to the anode of the fourth diode, which through the third resistor is connected to the tap of the main winding of the droplet DLC-i№ibTpa (and the cathode a n about % about one n n n g gtt the fourth diode is connected to the collector of the key transistor, and the additional and the main windings of the OLC filter throttles are connected according to.