SU1327081A1 - Apparatus for regulating constant voltage - Google Patents

Abstract

The invention relates to secondary power sources of radio equipment. The aim of the invention is to improve the quality of the stabilized voltage by reducing the noise arising from the regulation of the constant voltage on the load. The goal is achieved due to the fact that the device operates with virtually no through-current of the rectifying diodes 9. The voltage change at the output of the choke 19 can only occur after the zero current of the droplet, and hence the current of the turning off diode, vanishes. As a result, the activation of the corresponding diode occurs only after the current in the switched off diode is removed. 3 il.

Description

The invention relates to electrical engineering and can be used to regulate and stabilize a constant voltage across a load.

The purpose of the invention is to improve the quality of the stabilized voltage by reducing the noise arising from the regulation of the constant voltage on the load.

FIG. 1 shows a circuit diagram of the device proposed; in fig. 2 shows an example of the execution circuit of the control unit comparator; Fig. 3 shows time diagrams of voltages and currents at characteristic points of the circuit.

The device for regulating the DC voltage contains in series between the input terminals 1 and 2 the first 3 and the second 4 switching elements, the common point 5 of which is connected through a choke 6 to two chains 7 and 8 containing each series-connected diode 9 and filter capacitor 10 , a common point 11 connecting the diode and the first lead of the capacitor of each chain is connected to the corresponding first

25 device duty cycle. The synchronization of the work is carried out on the falling edge of the pulses of sequences 32 and 33. The arrival of the trailing edge of the pulses, for example, sequence.

the output pins 12 and the corresponding zone 32, causes the transis-inputs 13 of the control unit 14 to be locked, the outputs 15 connected to the control inputs 16 of the switching elements, the first 17 and the second 18 capacitors, the first of which is connected between the common point 5 of the switching elements and one input pin 1, between which and the point of connection 19 droplets 6 and successive chains included

torus 3. The current corresponding to the magnetic flux accumulated in the inductor 6 through the transistor 3 produces a recharge of the capacitor 17 and all the parasitic capacitors. A negative edge of the pulse sequence is formed. output 5 (sequence 34 in Fig. 3) switching elements. Front is part

torus 3. The current corresponding to the magnetic flux accumulated in the inductor 6 through the transistor 3 produces a recharge of the capacitor 17 and all the parasitic capacitors. A negative edge of the pulse sequence is formed. output 5 (sequence 34 in Fig. 3) switching elements. Front is part

The second capacitor 18, the input terminals of the oscillatory process, is connected to the corresponding second switching off of the transistor 3 to the output terminals 20 and 21 and to the input circuit consisting of throttles 6 to the inputs 22 of the control unit 14, and the capacitor 17. The process causes the capacitor filters of the chains to be opened by transistor 4 that the leads are connected to the corresponding comes when the voltage goes down

second output pins.

The control unit 14 comprises a comparator 23 connected by the corresponding inputs to the inputs 13 and 22 of the control device and the input 24 of the voltage supply, the converter

25 Voltage - frequency, frequency dividers 26, circuits 27 AND and drivers

26 control pulses. The comparator 23 (Fig. 2) contains

operational amplifiers 29 and 30 difference voltages, connected by corresponding inputs to inputs 13 and 22 of control unit 14, and summing the collector of transistor 4 with respect to the emitter (in the time diagram is not shown by scaling ratios). Transistor 4 is unlocked

5Q inversely (for transistors that do not allow inverse switching at high currents, a diode should be parallel to it), fixing the voltage at the output 5 at level zero.

gg The current accumulated in the inductor 6 (diagram 36 in Fig. 3) begins to fall while holding the transistor 4 in saturation, and the voltage across the collector is zero. The same current is kept from

A power amplifier 31, connected by one of the inputs to the outputs of the difference voltage amplifiers, and the other to the input 24 of the reference voltage supply.

FIG. 3 denotes a sequence of 32 excitation pulses arriving at the switching element 3, a sequence of 33 excitation pulses arriving at the switching element 4, the voltage diagram 34 at the output of the switching elements 3 and 4 (point 5), the voltage diagram 35 at the output of the drossel 6

(point 19), diagram 36 currents in the choke 6.

The device works as follows.

The control unit 14 forms a sequence of excitation pulses (32, 33 in Fig. 3), delayed relative to each other by I. These sequences control the operation of the switching elements 3 and 4, causing

device duty cycle. Work is synchronized along the falling edge of the pulses of sequences 32 and 33. The arrival of the falling edge of the pulses, for example, sequence.

32, causes a transis

32, causes a transis

torus 3. The current corresponding to the magnetic flux accumulated in the inductor 6 through the transistor 3 produces a recharge of the capacitor 17 and all parasitic capacitors. A negative edge of the pulse sequence is formed. output 5 (sequence 34 in FIG. 3) of commuting elements. Front is part

the oscillatory process excited by turning off the transistor 3 in the circuit consisting of the droplets 6 of the capacitor 17. The process unlocks the transistor 4, which the procollector of transistor 4 has in relation to the emitter (in the time diagram is not shown in scale ratio). Transistor 4 is unlocked

inversely (for transistors that do not allow inverse switching at high currents, a diode should be parallel to it), fixing the voltage at output 5 at the zero level.

The current accumulated in the inductor 6 (diagram 36 in Fig. 3) begins to fall, keeping the transistor 4 in saturation, and the voltage on the collector is zero. The same current is kept from i, fixing

Indoor diode 9 of the output circuit Drossel 19 - the connection point of the chains 7 and 8 - voltage equal to the output voltage (voltage across the capacitor 10) of the chain 8. When reducing the current to zero, transistor 4 would become locked, changing the voltage on the collector, but this does not occur, since the excitation pulse, which controls the process, is at this point in time (sequence 33 in Fig. 3) and keeps transistor 4 on. The diode 9 of the string 8 is closed and the voltage at the output 19 begins to change. The front of the change (diagram 35 in Fig. 3) is part of an oscillatory process formed by the circuit from the throttle 6 "capacitor 18

The process unlocks the diode of the chain 7, and this occurs when the voltage decreases at output 19 less than the voltage at output 11 of the chain 7. The voltage at output 19 is fixed at a new level, and the current in throttle 6 begins to increase in the opposite direction. After the arrival of the locking front (the front locking the transistor 4) of the sequence 33, the current stored (in the opposite direction) in the throttle through the transistor 4 causes the inverse switching on of the transistor 3 and the development of a new cycle, which is analogous to that described. We estimate the process quantitatively. T as voltage power pulses at output 19 (diagram 35 in FIG. 3)

Close to rectangular, and the voltage at output 5 (figure 34 of fig. 3 is also rectangular, works of throttle 6 can be made up of sections where choke 6 is under Permanent (for the duration of the section) voltage. Then The process in the throttle can be represented as follows:

/ 2I 1

. hl ".o then

dt, since c-const,

g - UL- t.

 L

where T. - the duration of the site;

U is the voltage across the choke for a duration of 1; L - throttle inductance; The current charges the capacitors. 10. Discharges the capacitors. Direct current.

load i

tf.

Then

1, -Ti -g-, from where

I

cpi

- 2L

Thus, the average current for the period of the operating cycle, including 1CH1T p sections, can be represented as follows:

one . I

wed

MLli 2L

Take and, - equal to the minimum voltage on the choke, then

Have

and,

4L

t y tt-h-i

  4L

(one)

where T is the period of the working cycle.

As follows from (1), reducing the frequency of the follow-up of the working cycles allows an increase in the current consumed by the loads from the chains 7 and 8, or the voltage on the loads. This effect is visible from the timing diagrams 34-36 (Fig. 3).

Having taken the load in the form of active resistance, one can use formula (1) directly to estimate the quality of the DC voltage control. From (1) it can be seen that the regulation is proportional in nature, can be carried out in a wide frequency range, depends little on the load and for these reasons favorably differs from the variants using the resonant properties of con

40

45

50

The essential feature of the proposed device is the fundamental ability to operate without rectifying diodes 9 through-currents. It is obtained due to the fact that the voltage change at the output of the chokes of 19 can occur only after the current of the droplets is zero (diagram 35 and 36 in Fig. 3 ), and hence the current of the turning off diode. It follows that the diode is turned on only after the current in the switched off diode is removed, i.e. in the absence of through-current diodes. Interference in the device is reduced.

The transistors are turned on by an oscillatory process (without the part of the excitation pulses). The currents and voltages are changed by the inductance of the throttles, capacitors, and parasitic capacitances and are made only after turning off the previously switched transistor 132

p a, hence the lack of through current through switched transistors and the minimum level of radiated noise.

Claims (1)

Invention Formula A device for controlling a DC voltage, containing the first and second switching elements connected in series between the input terminals, the common point of which is connected via a choke to two chains, including each successively connected diode and filter capacitor, a common connection point the diode and the first lead of the capacitor of each chain are connected to the corresponding first output pins and the corresponding inputs of the control unit, the outputs connected to the control unit The main inputs of the coupling elements are the first and second capacitors, characterized in that in order to improve the quality of the stabilized voltage by reducing the interference that occurs from 1 to 1X when regulating the DC voltage on the load, the first capacitor is connected between the common point of the switching elements and one input terminal , between which and the point of connection of the throttles and serial chains the second capacitor is connected, the input terminals are connected to the corresponding second output terminals and input inputs of the control unit In this case, the capacitors of the filters of the chains are connected by the second pins to the corresponding second output pins. FIG. 2 Editor E. Kopcha Compiled by A. Kolokkin Tehred A. KravchukKorrektor A, Iptat Order 3389/44 Circulation 863 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4