SU1206938A1 - Transistor bridge d.c.voltage converter - Google Patents

Description

The invention relates to electrical engineering and can be used in the sources of secondary power supply systems of radio engineering, automation and computer technology.

The aim of the invention is to increase reliability by simplifying the circuit and eliminating the overload currents of the transistor switches of the converter.

The drawing shows a DC transistor bridge converter circuit.

The circuit contains two leading x 1 and 2 and two slave 3 and 4 power switches, in series with which cut-off diodes 5-8 and blocking elements 9 and 10, a load 11 connected to the output terminals of the converter connected through return diodes 12-15 s the first 16 and second 17. input pins, the current-limiting resistors 18 and 19 included in the input circuits of the driven transistor switches 3 and 4, to which the inputs of the sensors 20 and 21 of the key state monitoring are connected, as well as two logic elements 2 and 23 matches whose inputs are connected with dots with Connections of blocking elements 9 and 10 and cut-off diodes 5 and 7 through resistors 24 and 25 and control unit 26.

In a particular implementation of a constant-voltage transistor bridge converter, logic elements 22 and 23 are matched on thyristor optocouplers, and blocking elements 9 and 10 on seven-watts.

The device works as follows.

In the initial state, the pulses do not come from the control unit 26, therefore leading. 1 and 2 and the slave 3 and 4 transistor switches are turned off. The current through the load P does not leak. A voltage is applied to the sensors 20 and 21 of the control of the status of the keys, as a result, the inputs of the blocking elements 9 and 10 receive switching signals, however, the blocking elements are switched off via the power circuit.

Upon receipt of the opening pulse from the control unit 26 to the input of the driving transistor switch 1, only one diagonal of the converter is turned on

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the transistor switches 1 and 4. Assuming that the transistor switches 2 and 3 are turned off, the state control sensor 20 outputs a signal to the control input of the matching logic element 22. Since the master power switch 2 is turned off, a signal also arrives at the other input of the logic element 22. When these two signals coincide in time, the logic element 22 of the match issues a sigal — a command to turn on the blocking element 9, as a result, this blocking element and the driven transistor switch 4 turn on, and a current flows through the load 11.

When changing the polarity of the signal

0, the control unit turns on the master: transistor switch 2, but the blocking element 10 cannot be turned on until the driven transistor switch 4 is turned on, the bypass switch 21 for monitoring the status of the key. Moreover, in the device, it is possible that after removing the switch-on signal from the working diagonal (keys 1 and 3), switch-off of key 4 will occur earlier than key 1, due to the action of the source of the blocking signal (forced lock of key 4). After turning off the slave power key 4, the key state control sensor 2 outputs a signal to the control input of the matching element 23. Inputting the input signal to the master transistor switch 2 (diagonal with keys 2 and 3J leads to unlocking key 2 and, if there was no connection between the input of logic element 23 for matching and control input of the slave transistor switch 4 through the corresponding resistor 19 with one From the poles of the cut-off diode 5 and the blocking element 9, key 3 would turn on with key 1 still open, which would result in the flow of through current through the rack with keys 1 and 3. Control the same state of key 1 (i.e. the presence of the specified link) is to exclude such mode of operation of the circuit with a through current.

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After turning off the master transistor switch 1 to the second input element 23 receives a signal. With

3; 1 the coincidence of these two signals in time the logic element 23 matches the signal — a command to turn on the blocking element 10. After turning on the blocking element 10, the transistor switch 3 is turned on accordingly, the current in the load 11 is reversed.

A similar elimination effect: the flow currents in transistor switches 1-4 can be obtained by connecting the second inputs of logic elements 22 and 23 to coincide directly with the second power output of the leading transistor switches 1 and 2.

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Thus, in the proposed transistor bridge voltage converter, reliability is achieved by simplifying the circuit in comparison with the known bridge converters, as well as eliminating the overload currents of the transistor switches, due to the simultaneity of their opening.

10 In this case, the requirements for block 26 are reduced in terms of the possibility of imposing polarities of the switching signals, i.e. the control unit can be executed not by the trigger principle,

15 which simplifies the construction of the control circuit.

VNIIPI Order 8732/58 Circulation Circuit Subscription Affiliate ShSh Patent, g.Uzhgorod, ul.Proektna, 4

Claims (4)

1. A transistor DC-DC bridge converter containing two leading power switches, the control electrodes of which are connected to the outputs of the control unit, the first power electrodes are connected to the first input terminal of the converter, and the second power electrodes are connected via series-connected blocking elements and flowing diodes to the corresponding output terminals a converter, two slave power switches, current limiting resistors are included in the input circuits, the first power electrodes are connected s to the second input terminal, and the second power electrodes are connected through the corresponding cut-off diodes to the output terminals of the converter, sensors for monitoring the state of the keys, the inputs of which are connected in parallel with the slave power switches, and the output terminals of the converter are connected through the return diodes to the input terminals, characterized in that , in order to increase reliability by simplifying the circuit and eliminating the overload currents of the transistor switches of the converter, two logical matching elements are introduced, the outputs of which connected to the control inputs of the blocking elements, the first inputs are connected to the outputs of the sensors for monitoring the state of the transistor keys of the opposite arm of the converter, while the current limiting resistor of the slave power switch is connected to the point of connection of the blocking element and the cut-off diode of one converter arm and the second input of the logic element is connected through the resistor coincidence of the same transducer arm. 2. The converter according to π. 1, characterized in that the connection of the sensor monitoring the state of transistor switches with a logical matching element is made optical. 3. The converter according to π. 1, characterized in that the coincidence logic element is made on a thyristor optocoupler. 4. The converter according to π. 1, characterized in that the blocking element is made on the seven-cell. SU „„ 1206938