SU1121756A1 - Stabilized d.c. voltage converter - Google Patents

Abstract

STABILIZED CONSTANT VOLTAGE CONVERTER, .Containing a single-cycle transistor converter cell with a direct BKjno4eHiieM rectifier diode and inductive-capacitive diode; a filter whose output is connected to the output terminals of the converter and to the first input of a pulse-width modulator, the second input of which is connected via the sawtooth generator to the output of the master oscillator, a logical inverter whose output is connected to the first input of the first coincidence element, the second input of which connected to the input of an inductive capacitive filter, and the output to the base of the first transistor of a push-pull transformer control amplifier, the secondary winding of which is connected It is connected to the control junction of the transistor of a single cycle transducer cell, and the current supplying resistors are included in the emitter circuits of the transistors of the control amplifier, and the power supply of the control amplifier is connected to the input terminals of the converter, in order to reduce the reliability of the converter by eliminating the false switch. the transistor of a single-cycle converter cell in idle mode (L of that turn, a second coincidence element was entered into it, the first input of which is connected to the output of a latitudinal and a pulse modulator, a second input to the output of the master oscillator, and an output to the base of the second transistor of the control amplifier, while the HS input of the logical inverter is connected to the output of the generator (its generator, and the third input of the first coincident element) O1 modulator. O5

Description

i

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

Stabilized DC-to-DC converters are known, which contain a single-cycle transistor converter cell with a direct switching on rectifier diode and an inductive-capacitive filter, the output of which is connected to the output terminals of the device and to the input of a pulse-width modulator, the second input of which is through a ramp generator connected to the output of the master oscillator, and the output to the input of a push-pull transformer control amplifier, the output winding of which is connected to the control he single-cycle entrance of transistor converters lj and 2.

The lack of known devices lies in their low reliability when operating in the mode of small loads and idling.

The closest to the proposed technical entity is a stabilized DC voltage converter containing a single-cycle transistor converter cell with a direct switching-on rectifier diode and an inductive-capacitive filter, the output of which is connected to the output high, the water of the converter and to the first input latitude -pulse modulator, the second input of which is connected to the output of the master oscillator through the saw-tooth generator, a logic inverter whose output is connected the first input of the first coincidence element, the second input of which is connected to the input of an inductive capacitive filter, and the output to the base of the first transistor of a two-stroke transformer control amplifier, the secondary winding of which is connected to the control transistor of a single-cycle conversion cell, and to the emitter circuits of the transistor control amplifier the current-setting resistors are turned on, and the power amplifier control output is connected to the output pins of the converter.

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A disadvantage of the known device-g is its low reliability due to the fact that when it is idling or in low load current mode, when the pulse width at the unlocking of the transistor of a single-ended converter is minimal and significantly less than the time of absorption of minority carriers in the base circuit of the specified transistor (especially when the absorption time is comparable to the conversion frequency period), the open state time of the first transistor of the control amplifier

longer than the open state time of the second transistor of the control amplifier. As a result, the two-stroke control amplifier transformer is magnetized in such a

The fact that when it is demagnetized in the pause of the control signal on the first winding creates a voltage that opens the transistor of the single-ended converter. Such untimely opening of the transistor of a single-ended converter in the pause of the control signal disrupts the stable operation of the device, as a result of which transients occur in its smoothing filter, at which the current flowing in the inductor, and through the transistor of the single-ended converter, reaches dangerous for the latter value. The aim of the invention is to increase the reliability of a stabilized DC-voltage converter by eliminating the false activation of a single-phase transistor in idle mode.

This goal is achieved by the fact that in a stabilized DC voltage converter containing a single-ended transistor converter cell with a direct voltage

switching on a rectifying diode and an inductive-capacitive filter, the output of which is connected to the output pins of the converter and to the first input of a pulse-width modulator, the second input of which is connected to the output of the master oscillator through the generator of the pshy shaped voltage, the logical inverter whose output is connected to the first input

the first coincidence element, the second input of which is connected to the input of an inductive capacitive filter, and the output to the base of the first transistor of a push-pull transformer control amplifier, the secondary winding of which is connected to the control transition of the transistor with a single-cycle converter cell and the emitter circuits of the control amplifier transistors are included current-supplying resistors, and the input of the power supply of the control amplifier is connected to the input terminals of the converter, a second coincidence element is introduced, the second input is connected to the output of the pulse-width modulator, the second input is connected to the output of the master oscillator, and the output to the base of the second transistor of the control amplifier, while the input of the logic inverter is connected to the output of the master generator, and the third input of the first element matches pulse width output. modulator FIG. 1 shows a diagram of the device; in fig. 2 - time diagrams of his work. The stabilized DC / DC converter contains a single-ended transistor converter 1 with direct switching on the rectifying diode and an inductive-capacitive filter 2, the output of which is connected to the first input of the horn-pulse modulator 3, the second inlet of which is connected via a ramp generator to the output of the master oscillator 5, the logical inverter 6, the first 7 and the second 8 elements of coincidence, the first 9 and second 10 transistors of the push-pull transformer control amplifier, the secondary winding of the trans The transformer 11 of which is connected to the controlled transition of the transistor 12 of the single-ended converter 1. Consider the operation of the proposed device in accordance with the timing diagrams (see Fig. 2), where Uj is the output voltage of the master oscillator 5; Ne is the output voltage of the inverter 6; UgM output voltage of the device; (Jg, y is the output voltage of the device at idle; d) - sawtooth voltage of the generator 4; L, is the output voltage of the pulse-width modulator of torus 3; - output voltage of the first element of coincidence 7; (tcy output voltage of the second element coincidence 8; Ug is the output voltage at the input of the filter 2; about the dissolution time of the power transistor 12. The device operates as follows. At the nominal load of the proposed device from the output of the master oscillator 5 to the input of the inverter 6, the first input of the second The coincidence element 8 and the input of the sawtooth voltage generator 4 receive a sequence of rectangular voltage pulses Uj- (Fig. 2a). From the output of the inverter 6, voltage pulses Tsz podczts to the first input of the first element 7 coincidence. The output voltage UQ of the sawtooth voltage generator 4 is fed to the first input of the pulse-width modulator 3, to the second input of which the output voltage of the device U is applied (Fig. 2c). The pulses of the output voltage of the pulse-width modulator 3, duration which is inversely proportional to the change in the output voltage of the device (Fig. 2d), are fed to the second and third inputs, respectively, of the second 8 and first 7 coincidence elements. In this case, a sequence of voltage pulses 2d is formed at the output of the second coincidence element 8, the duration of which is determined by the pulse duration of the output voltage of the pulse-voltage modulator 3, the falling edges coincide with the falling edges of the voltage pulses Uj-master oscillator 5, and the amplitude is 1 (Fig. 2d). With each pulse, the second transistor 10 opens, the primary frequency transistor 9 is closed, and a voltage is applied to the primary winding of the transformer 11, at which transistor 12 opens. At the input of the filter 2, voltage pulses LIg are formed and fed to the second input of the first element 7 (Fig. 2e), the duration of which is longer than the voltage pulse 0 by the resorption time of the bias (. Minor carriers of the transistor 12.) a voltage pulse Ll; 1 appears at the first input of the first element at its output (Fig. 2h). This causes the second transistor 10 to close and the first transistor 9 to open, a voltage appears at the primary winding of the control transistor 11 , and begins The transistor 12 is locked shutdown. After a time equal to rac, transistor 12 closes, the input voltage of filter 2 and, consequently, the output voltage Uc becomes equal to zero, and transistor 9 is formed at the output of the first element 7 of coincidence. U j, whose duration is equal to the time of locking the transistor 12, which is practically equal to the time of absorption of bpac. minor carriers of its base (Fig. 2h). Here, the duration of the voltage pulse at the output of the second element 8 coincidence is longer than the duration of the pulse at the output, and the first element 7 coincides. Therefore, the control transformer 11 has a magnetization such that during the demagnetization process, a voltage is formed on the first winding of the winding, which locks the power transistor 12.

When the proposed device is idling, the parameters of the voltage impulses at the output of the master oscillator 5 and the logic inverter 6 are similar to their parameters in the nominal mode of operation (Fig. 2a, b)

The output voltage of the device is somewhat larger (see Fig. 2c), as a result of which the duration of the voltage pulses at the output of the pulse-width modulator 3 and the second coincidence element 8 is much less (Fig. 2c, d, e). The voltage pulses at the input of the filter 2, and consequently, at the input of the first olemept, the coincidences are non-ideal in shape (Fig. 2e) due to

discharge through the windings of the output transformer of the single-ended converter of parasitic interturn capacitances. The duration of the pulses of the output voltage of the first element 7 coincidence is limited by the duration of the pulse of the output voltage O jUHJVv of the pulse-width modulator 3 (see Fig. 2h). As a result, the duration of the pulses of the unlocking of the transistors 9 and 10 are equal to each other and the time spent under the voltage of the primary windings of the transformer 1t is about the same, which eliminates such magnetization of the transformer 11-, in which during the demagnetization process the first transistor 12 appears in the first winding living

In the proposed device, in comparison with the known at idle speed, the distortion of the pulse shape of the voltage at the filter inlet, due to the discharge between the turns

the capacitances of the output transformer of the single-ended converter, does not affect the pulse duration of the locking of the power transistor. This eliminates the magnetization of the control transformer, which in the course of demagnetization of the latter causes a voltage on its first winding to occur in the pause of the control signal that unlocks the transistor of the single-phase voltage converter. As a result of this, magnetisation does not occur in a singly. a transformer of a power amplifier and an increase to unacceptable values of currents flowing through the transformer of a single-ended converter, which ensures reliable operation of the device at idle.

Claims (1)

A STABILIZED DC / DC converter containing a single-cycle transistor converter cell with direct connection of a rectifier diode and an inductive-capacitive filter, the output of which is connected to the output terminals of the converter and to the first input of the pulse-width modulator, the second input of which is connected to the saw-tooth voltage generator ) a rotor, a logical inverter, the output of which is connected to the first input of the first coincidence element, the second input of which is connected to is connected to the input of the inductive-capacitive filter, and the output is to the base of the first transistor of the push-pull transformer control amplifier, the secondary winding of the transformer of which is connected to the control junction of the transistor of a single-cycle converter cell, and current-setting resistors are included in the emitter circuits of the control amplifier transistors, and the power input of the control amplifier is connected to the input terminals of the converter, characterized in that, in order to increase the reliability of the converter by eliminating false of switching a single-cycle conversion cell transistor in idle mode, a second coincidence element is introduced into it, the first input of which is connected to the output of a pulse-width modulator, the second input to the output of the master oscillator, and the output to the base of the second transistor of the control amplifier, the input of the logical inverter is connected to the output of the master oscillator, and the third input of the first coincidence element is connected to the output of the pulse-width modulator. SU η »1121756 1,112