SU1088121A1 - Electronic switch - Google Patents

Abstract

ELECTRONIC KEY containing a power transistor, a transformer with one input and two output windings, a magnetic amplifier with a working, current and control windings, a control transistor, a pulse-width modulator, a generator, a voltage regulator, two diodes, a power supply bus capacitor and a load The emitter of the power transistor is connected to one of the power supply busbars and the middle output of the first output winding of the transformer, the extreme outlets of which are connected through the working winding of the magnetic amplifier to The base of the power transistor, the collector of which through the current winding of the magnetic amplifier and the load is connected to another power supply bus, the emitter of the control transistor is connected to the middle terminal. The second output winding of the transformer, the extreme outputs of which through the control winding of the magnetic amplifier are connected to the collector of the control transistor, the input winding of the transformer is connected between the generator outputs, the power supply wires of which are connected to the corresponding voltage supply voltage regulators, the output of which is common the bus is connected to the power bus of the modulator, the base of the control transistor is connected to the output of the modulator, and the input of the modulator to the input bus is different in that o, in order to increase reliability, a blocking transistor (L Zener diode, a resistor, a third diode, an I element, whose output is connected to the base of the blocking transistor and through a resistor to the first electrodes of the diodes, the first terminal of the capacitor, and the first input of the I element, at the same time, the second electrodes of the first and second diodes are connected to the extreme terminals of the second output coil of the transformer, the second electrode of the third diode is connected to the collector frame of the control blocking transistor and through the zener diode to the emit frame control and a blocking transistor, the second terminal of the capacitor and to the common voltage stabilizer schine and AND gate, a second input coupled to an output voltage stabilizer.

Description

The invention relates to a pulse technique and can be used in automation devices. The electronic key is known, which contains a power transistor, a transformer, diodes, and a generator. The cone of this key is low efficiency due to significant energy losses in the control circuit of the power transistor. Also known is an electronic switch containing a power transistor, a transformer with one input and two output windings, a magnetic amplifier with a working, current and control windings, a control transistor, a pulse-width modulator, a generator, a voltage regulator, two diodes, capacitor, power supply busbars and load; the emitter of the power transistor is connected to one of the power supply busbars and the middle output of the first output of the transformer, the extreme of which through the working winding of the magnetic amplitude connected to the base of the power transistor, the collector of which through the current winding of the magnetic amplifier and the load is connected to another power supply bus, the emitter of the control transistor is connected to the middle output of the second output winding of the transformer, the extreme leads of which are connected to the collector through the control winding of the magnetic amplifier the control transistor, the input winding of the transformer is connected between the outputs of the generator, the power supply lines of which are connected to the corresponding power supply lines. and the power bus of the voltage stabilizer, the output and common bus of which are connected to the power bus of the modulator, the base of the control transistor is connected to the output of the modulator, and the input of the modulator to the input bus 2. The disadvantage of the known device is the low reliability due to the large heat gap in the power transistor during the rise of the output voltage of the generator and voltage regulator. The aim of the invention is to increase reliability. This goal is achieved by the fact that an electronic switch containing a power transistor, a transformer with one input and two output windings, a magnetic amplifier with a working current and control windings, a control transistor, a pulse width modulator, a generator, a voltage stabilizer, two diodes, a capacitor, a power supply bus and a load, and the emitter of the power transistor is connected to one of the power supply buses and the middle of the first output winding of the transformer, the extreme outputs of which are through the working winding the magnetic amplifier is connected to the base of the power transistor, the collector of which through the current winding of the magnetic amplifier and the load is connected to another power supply bus, the emitter of the control transistor is connected to the middle terminal of the second output winding of the transformer, the extreme terminals of which are connected through the control winding of the magnetic amplifier the collector of the control transistor, the input winding of the transformer is connected between the outputs of the generator, the power supply of which is connected to the corresponding buses of the source The power supply voltage regulator, whose output and common bus are connected to the power bus of the modulator, the base of the control transistor is connected to the output of the modulator, and the input of the modulator to the input bus, a blocking transistor, a zener diode, a resistor, a third diode, element And, the output of which is connected to the base of the blocking transistor and through a resistor - to the same electrodes of the first diodes, the first terminal of the capacitor and the first input of the element And, while the second electrodes of the first and second diodes are connected to the outermost the outputs of the second output winding of the transformer, the second electrode of the third diode is connected to the collectors of the control and blocking transistors and through the zener diode to the emitters of the control and blocking transistors, the second capacitor terminal and the common bus of the voltage regulator and element, the second input of which is connected to the output voltage regulator. The drawing shows the electrical circuit of the proposed electronic key. The electronic key contains a power transistor 1, a transformer 2 with the first output winding 3 with an average

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pin 4 and extreme leads 5, second output winding 6 with a middle lead .7 and extreme leads 8 and input winding 9, magnetic amplifier 10 with a working winding 11, current winding 12 and control winding 13, load 14, power supply 15, control transistor 16, pulse width modulator 17 with control input 18, output 19 and power supply buses 20, generator 21 with power supply buses 22 and output 23, blocking transistor 24, zener diode 25, resistor 26, capacitor 27, three diodes 28-30 , constant voltage regulator 31 with 32 power supply tires and output 33, element AND 34 with two control inputs 35 and 36 and exit i house 37.

The emitter of the power transistor 1 is connected to the average output 4 of the output winding 3 of the transformer 2, the extreme terminals 5 of which through the working winding 11 of the magnetic amplifier 10 are connected to its base. The collector of the power transistor 1 through the winding 12 (winding current form) of the magnetic amplifier 10 and the load 14 is connected to one of the buses of the power source 15. The emitter of the control transistor 16 is connected to the middle lead 7 of the output winding 6 of the transformer 2, the extreme leads 8 of which through the control winding 13 of the magnetic amplifier 10 are connected to its collector. The base of the control transistor 16 is connected to the output of the pulse-width modulator 17, the power supply bus 20 of which is connected to the output 33 of the constant-voltage regulator 31. The output 23 of the generator 21 is connected to the input winding 9 of the transformer 2, the collector of the blocking transistor 24 is connected to the cathode of the Zener diode 25, the anode of the diode 28 and the collector of the control transistor 16. The base of the blocking path; And the 34 and the output of the resistor 26 Its other output is connected to the cathodes of the diodes 28-30, the first input 35 of the element 34 and one output of the capacitor 27. Its other output is connected to the combined emitters of the blocking transistor 24 and the control transistor 16 and the anode of the zener diode 25. Anodes iodov 29 and 30 are connected to terminals 8 extreme vyhod214

winding 6 of the transformer 2. The second input 36 of the AND element 34 is connected to the output 33 of the constant voltage regulator 31, the busbars 32 of which are connected to the power supply source 15. Bus 22 power generator 21 is also connected to the power source 15. The common busses of the constant voltage regulator 31, the AND 34 element and the pulse-width modulator 17 are combined and connected to the middle cable. 7 of the control winding 6 of the transformer 2,

The device works as follows.

The voltage between points B is proportional to the voltage between points A and B, since the base circuit of the power transistor f and the collector-emitter circuit of the control transistor 16 are made according to the similar principle. Therefore, in the case when the control transistor 16 is saturated and the voltage between points A and B is zero, then the voltage between points A and B is also zero. The power transistor 1 is closed.

When the power supply 15 is turned on, the voltage is simultaneously applied through the load 14, the current-carrying current 12, which functions as a feedback winding of the magnetic amplifier 10, to the collector-emitter junction of the power transistor 1, to the generator power supply 22, which produces a rectangular voltage and busses 32 of a constant voltage regulator 31. The time of the output of the generator 21 and the constant voltage regulator 31 to the nominal mode of operation is determined by transients

processes occurring in these blocks. Until the voltage at the input winding 9 of transformer 2, determined by the voltage of the output 23 of the generator 21, and the voltage at the output 33 of the constant-voltage regulator 31 reaches its nominal values, the power transistor 1 is closed, as the points are shorted A and B. At the first moment after switching on the power supply source 15. power supply, when there are no voltages at outputs 23 and 33, points A and B are shorted through diode 28 and capacitor 27. As the voltage increases on the output winding 6 of transformer 2 , the voltage on the capacitor is 27 It is equal to the value equal to the rectified diodes 29 and 30 of the rated voltage on this winding. At the time; As soon as the voltage across the capacitor 27 exceeds the base-emitter junction voltage of the blocking transistor 24, a current flows through the resistor 26 to its base, ensuring its steady state and, thus, the short-circuited state of points A and B before the end of the transients. The signal allowing the normal operation of the transistor switch is generated as follows. The inputs 35 and 36 of the element 34 are supplied with the voltage of the output 33 of the stabilizer 31 of a constant voltage and rectified by the diodes 29 and 30 of the voltage of the winding 6 of the transformer 2. The signal from the output 37 of the element 34 provides for the closing of the blocking transistor 24 only if both of them on their inputs reach nominal values. With such a signal, the control transistor 16, which corresponds to the control of the power transistor 1, is controlled by signals arriving at its base from the output 19 of the pulse-width modulator 17 in accordance with the signal Ug fed to the input 18, thus achieving regulation average current 3e, j, load 14. When any voltage at control inputs 35 10 1. 6 and 36 element And 34 does not match the nominal, for example, when power supply 15 is turned off, the signal from its output 37 does not provide closing b okiruk Oleg Zhegoyev .tranzistora 24. In this case, the current through resistor 26 discharge the capacitor 27 is supplied to the base of the blocking transistor 24, providing its saturated state, i.e. The shorted state of points A and B. Stabilitron 25 protects the collector-emitter junction of control transistor 16 and blocking transistor 24 in case of overvoltages at points A and B, for example, with parasitic voltage surges at the moments of switching the power transistor 1. Diode 28 prevents leakage the discharge current of the capacitor 27 through the open collector-emitter junction of the control transistor 16 and the blocking transistor 24 and the zener diode 25. The use of the invention will improve the reliability of the electronic key by providing a locked state of the power transistor during the switching transients of supply voltage. Electronic key tested in the composition of the power bridge converter with a power of 2 kW. Tests confirm the efficiency of the converter operation without additional switching devices, and the reliability of the bridge converter is increased by 10-15%.

Claims (1)

An electronic switch containing a power transistor, a transformer with one input and two output windings, a magnetic amplifier with a working, current and control windings, a control transistor, a pulse-width modulator, a generator, a voltage regulator, two diodes, a power supply bus capacitor and a load, the power emitter the transistor is connected to one of the buses of the power source and the middle terminal of the first output winding of the transformer, the extreme terminals of which are connected to the base through the working winding of the magnetic amplifier a transistor whose collector is connected through the current winding of the magnetic amplifier and the load to another bus of the power source, the emitter of the control transistor is connected to the middle terminal of the second output winding of the transformer, the extreme terminals of which are connected through the control winding of the magnetic amplifier to the collector of the control transistor, the input winding of the transformer is connected between the outputs of the generator, the power bus of which is connected to the corresponding bus power supply and power bus stabilizer voltage, the output of which and the common bus are connected to the power buses of the modulator, the base of the control transistor is connected to the output of the modulator, and the input of the modulator is connected to the input bus, characterized Q by the fact that, in order to increase the reliability, the blocking transistor, the zener diode, the resistor, the third diode, the And element, the output of which is connected to the base of the blocking transistor and through the resistor to the first of the same name, are introduced. diode electrodes, the first output of the capacitor and the first input of the And element, while the second electrodes of the first and second diodes are connected to the extreme terminals of the second output winding of the transformer, the second electrode of the third diode is connected to the collectors of the control blocking transistors and through the zener diode to the emitters of the control and blocking transistors, the second terminal of the capacitor and to the common bus of the voltage regulator and the element And, the second input of which is connected to the output of the voltage regulator. SU ... 1088121 1 10881