SU1056408A1 - Two-step d.c. voltage converter - Google Patents

Abstract

DOUBLE-SHAPED TRANSFORMERS ATERE CONSTANT VOLTAGE, containing. an inverter cell with power transistors connected to an output transformer having windings: feedback connected through base resistors to the base-emitter junction of power transistors, a control unit including a source of blocking pulses connected through the diode elements to the bases of power transistors, Recognized by the fact that, in order to increase reliability by eliminating the false triggering of the device, two transistors are introduced into the control unit, the emitter or wave of which is connected through the input a diode to the first input output of the power supply, while the collector of the first one through the inputted first resistor is connected to the first output of the diagonal of the alternating current of the first diode bridge, the diagonal of which is connected in series to the windings of the feedback circuit, and the collector of the second inserted transistor through the injected resistive voltage divider is connected to the output for connecting the source for (Perimeter voltage, with the midpoint of the resistive breakdown divider connected to the primary the output of the diagonal of the alternating current of the second diode bridge, and the second conclusions of the diameters of the alternating current of both diodes: bridges are connected.

Description

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ABOUT

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The invention relates to a class of devices for converting electrical energy of direct current and can find wide application in electroautomatic and computer technology for converting, amplifying, and transmitting galvanically developed DC and pulsed currents.

A constant voltage converter is known which is started by means of a circuit consisting of a transistor switch, a winding and contacts of an electromagnetic relay. When the inverter is excited, the start-up circuit is open and does not affect the operation, while the inverter generates alternating current through positive feedback circuits. To turn off the inverter, a C 13 power supply voltage is required.

The inverter cannot be in standby mode, since when energized, it is energized and generates continuously. Inverter operation is not possible with logic levels of integrated circuits.

Closest to the invention is a push-pull DC / DC converter containing an inverter cell on power transistors connected to an output transformer having feedback windings connected through base resistors to base-emitter junctions of power transistors, a control unit including a source of locking pulses connected via diode cells c. power transistors bases. A known transducer can be controlled by an NW logic integrated circuit.

However, the reliability of the converter is inherently low, since if the control pulses fail, a false alarm of the device is possible.

The aim of the invention is to increase reliability by eliminating false triggering of the device.

The goal is achieved by the fact that in a two-stroke DC / DC converter containing: an inverter cell on power transistors connected to an output transformer having feedback windings connected through base resistors to the base-emitter junction of power transistors, the control unit including a source of blocking pulses connected via diode elements to the bases of the power transistors; two transistors are introduced into the control unit, the emitters of which are connected through the input a diode to the first input power pin,

at the same time, the collector of the first of them is connected through the input of the first resistor to the first output of an alternating current diagonal of the first input diode bridge, the diagonal of which is connected in series to the feedback windings, and the collector of the second inserted transistor is connected to the output through a resistive voltage divider for connecting a blocking voltage source, with the midpoint of the resistive voltage divider connected to the first output of the diagonal of the alternating current of the second diode The leg of the bridge, and the second terminals of both diagonals AC diode bridges connected.

The drawing shows a schematic diagram of the proposed device.

The diagram shows an inverter cell with an output transformer 1 connected to power transistors 2 and 3, the control transitions of which through the base resistors 4 and 5 are connected to the feedback windings connected in series with the direct current diagonal pattern of diodes 6–9, The first output of the DC diagonal is through a resistor 10 and the power circuit of the first transistor 11 connected to a diode 12 connected to the first input terminal. The second transistor 13, connected by one of the power electrodes to the diode 12, is connected by another power electrode through a resistive voltage divider across resistors 14 and

15k source of locking voltage. The midpoint of the resistive divider is connected to one of the pins of the diagonal of the alternating current of the second diode bridge on diodes 16-19

The stresses on tires E and E are equal in magnitude and opposite in sign.

When the supply and blocking voltages are applied to the circuit and there are high levels of logic signals at inputs I and IJ, the inverter is in standby mode. In this case, the inverter consumes almost no current. A bridge of diodes 6-9 in the inverter is open positive feedback and there is no initial current of the power transistors through the closed transistor 11, and the blocking voltage EJ when the transistor 13 is closed along the circuits consisting of resistor 15, diodes

16 and 18 are attached to the emitter-base transitions of the anzistors 2 and 3.

The inverter triggers as the control signal levels change across the two inputs at the same time, and transistors 11 and 13 open.

Transistor 13 shuts down voltage, and transistor 11 closes the inverter positive feedback, and diode 12 - open transistor 11 - resistor 10 - diodes 6 and 7 of the feedback winding - resistor 4 and 5 and base-emitter transitions of transistors 2 and 3 current flows, opening the power transistors.

The inverter starts up, and alternating voltage appears in the secondary winding of the transformer, which can be rectified, smoothed, amplified and used depending on the specific case:

a) for transmission in galvanically isolated DC and pulsed currents (voltages) with connection to the secondary windings of rectifying-amplifying devices;

b) for driving high power amplifier stages;

c) to control the performance clips (on thyristors or transistors);

d) for use as a dc or voltage detector, if a controlled voltage or voltage drop is applied to one of the inputs

from the resistor included in the circuit to signal the presence of current, and to the other input to send a polling signal.

When the inverter is switched, the reverse half-wave current flows from the positive feedback windings through diodes 8, 17 or 9, 19 and resistors 4 or 5, respectively, which dampen the voltage spikes on the inductors of the windings, to improve the shape of the generated voltage. Changing the control signals from low to high on both inputs simultaneously or at least on one leads to braking of the inverter and putting it into standby mode.

Low level at the input I open-. The starting transistor 11, but under the action of locking its voltage supplied from the main transistors, it is kept in the closed state, while the inverter is not excited.

0 A low level at the input if opens the transistor 13, removing the blocking voltage from the bases of the main transistors to the absence of a bias current through the closed transistor 11,

5 and the open reverse prevents the occurrence of self-oscillations in the inverter.

Thus, the reliability of the inverter is ensured by the following

Q lyse factors:

1. In the standby mode, open positive feedback) the absence of the current opening the main transistors; locking action

5 voltage that actively closes the main transistors, by the absence of consumed current through the power supply circuit and the locking lap locking circuit, which ensures the optimal thermal conditions of the device in the waiting

 condition.

2. In the autogeneration mode, a high degree of availability of the inverter due to pre-applied voltages; the simultaneous action of two up5 equalizing signals; damping overshoot; launch threshold stability.

3. In the braking mode. The reliability of braking, which is carried out by the reverse change of at least one of the control actions on the control signal or in the event of a malfunction.

Claims (1)

TWO-STAGE DC-CONVERTER, containing an inverter cell on power transistors connected to an output transformer having windings: feedback connected through base resistors to the base-emitter junctions of power transistors, a control unit including a source of blocking pulses connected through diodes bases of power transistors, characterized in that, in order to increase reliability by eliminating false triggering of the device, two control units are introduced ranzistora whose emitters are connected through diode inputted to the first input terminal of the power supply, the collector of the first of them through the inputted first resistor connected to the first terminal of the first diagonal AC inputted first diode bridge diagonal of which is connected in series DC. into the feedback winding circuit, and the collector of the second transistor introduced through the introduced resistive voltage divider is connected to the output for connecting the source of the blocking voltage, the middle point of the resistive voltage divider connected to the first terminal of the alternating current diagonal of the second diode bridge, and the second terminals of the alternating current diagonals of both diode; ny bridges are connected.