SU1765886A1 - Electronic relay - Google Patents

Abstract

The invention relates to switching technology. The electronic relay contains a pulse generator 1, MOS transistors 2,15,16,19, a transformer 7, keys 8, 9, a source 10 of power. Depending on the state of the keys 8, 9, controlled by the input signal, pulses of opposite polarity are formed on the secondary windings of the transformer, under the influence of which, through the transistors 15, 16, the input capacitance of the switching transistor 19 is charged, thereby controlling the switching transistor 19. 2 Il.

Description

The invention relates to switching technology and can be used for contactless switching of electroautomatic devices.

A known control circuit for power field-effect transistors comprising a pulse generator, an inverter, first and second circuits AND, first and second transistors, a transformer whose secondary windings are connected to a control voltage generation circuit and a switching MOS transistor (FRG, OS number 3616097 , class H 03 K 17/687).

A disadvantage of the known circuit is its complexity and limited scope due to the lack of galvanic isolation of the switching MOS transistor from the power supply circuits of the control voltage generation circuit.

A distribution transformer device is known, comprising an inverter, first and second generators, first and second transistors, first and second transformers, first and second control transistors, first and second diodes, and a switching MOS transistor (FRG, application number OS35333798, CL 03 K 17/687, prototype).

A disadvantage of the known device is its complexity.

The aim of the invention is to simplify the device.

The goal is achieved by the fact that, in a known electronic relay containing a pulse generator, a transistor, the gate of which is connected to the output of the pulse generator, and the source is connected to the first power supply bus, the inverter, which is connected to the input bus, the first diode, the cathode of which is connected to the second power bus of the electronic relay, the switching MOS transistor, the second and third diodes, the first and second control transistors and a transformer, the first terminals of the first and second windings of which are interconnected, and the third and fourth windings under keys

WITH

WITH

Xj

About SP 00 00

about

between the gate and the source of the first and second control transistors, respectively, whose drains are connected to the cathodes of the second and third diodes, respectively, the anode of the second diode is connected to the gate of the switching MOS transistor and the gate of the second control transistor, the anode of the third diode is connected to the gate of the first control transistor , the first output bus and the source of the switching MOS transistor, whose drain is connected to the second output bus of the electronic relay, the first and second keys are introduced, the first outputs of which are under lyucheny to the second power bus, control inputs - to the output and input of the inverter, respectively, the second output - to a second terminal of the first and second windings of the transformer, respectively, first terminals of which are connected to the anode of the first diode and the drain of the transistor.

The proposed technical solution differs from the prototype in that it introduces the first and second keys, the outputs of which are connected between the power bus and the second terminals of the first and second transformer windings, and the control inputs are connected to the output and input of the inverter, respectively, the first terminals of the first and second windings the transformer is connected to the anode of the first diode and the current of the transistor.

Similar electronic relays with the indicated set of distinctive features have not been revealed by the results of patent research, i.e. The proposed solution falls under the criterion Significant differences.

The presence of the indicated set of distinctive features in the proposed technical solution makes it possible to simplify the device circuit by eliminating a generator, a transformer, a diode and a transistor.

Figure 1 shows a diagram of an electronic relay; Fig. 2 shows voltage plots explaining the operation of the device.

The electronic relay contains a pulse generator 1 connected to the gate of transistor 2, the source of which is connected to the first power supply bus 3, and the drain to the anode of the first diode 4 and the first terminals of the windings 5, 6 of the transformer 7, the second terminals of which are connected to the second outputs of the keys 8, 9, the first outputs of which are connected to the second power supply bus 10, and their control inputs are connected to the output and input of the inverter 11, respectively. The input of the inverter 11 is connected to the input bus 12. The windings 13,14 are connected between

the source and the gate of the control transistors 15, 16, respectively, whose drains are connected to the cathode of the diodes 17, 18, respectively. The anode of the diode 17 is connected to the gate of the MOS transistor 19 and the gate of the control transistor 16. The anode of the diode 18 is connected to the gate of the control transistor 15, the first output bus 20 and the source of the switching MOP0 of the transistor 19, whose drain is connected to the second output bus 21.

The electronic relay works as follows

In the initial state on the input bus

5 12, the input signal of the low voltage level (log.0) is applied, respectively, the voltage at the output of the inverter 11 is high (log.1), while the key 8 is closed and the key 9 is open. The generator forms a continuous sequence of pulses with a duty cycle of 2, which is applied to the gate of transistor 2. Under the influence of pulses, switching of transistor 2 occurs and forms on the winding

5 to 5, connected via a closed key 8 to the power supply bus 10, of a sequence of pulses of positive polarity. Winding 13 and 14 are included in antiphase with respect to winding 5; so the pulses

0 on the windings have a negative polarity. At the end of each pulse, a reverse surge occurs on the windings of the transformer 7, due to a decrease in the magnetizing current of the winding 5. The back surge voltage is limited by a diode 4 connected to the winding 5 via a closed switch 8. Under the influence of the pulses, the control transistor 16 is closed and the control transistor 15 open, through open

0, the transistor 15 is charged to the input capacitance 22 of the switching MOS transistor 19, the source potential being higher than the gate potential and the MOS transistor 19 is in the non-conductive state 5. In the pauses between pulses, the transistor 16 is closed, because the amplitude of the back surge, limited by diode 4, is less than the threshold for unlocking the transistor. A diode 17 prevents the input capacitance 22 from discharging through the control transistor 15, which can be opened by the voltage on the input capacitance 22. Thus, in the pauses between the charge pulses on the input capacitance 22, the switching voltage is also saved

5, the MOS transistor 19 is held in the closed state.

When a high level signal is applied to the input bus 12, the key 9 is closed and the key 8 is opened. A winding 6 is connected to the power bus 10, which is turned on

according to the windings 13 and 14 of the transformer 7, therefore, the pulse voltage on them will have a positive polarity, thus the control transistor 16 opens and the transistor 15 closes. The input capacitance 22 is recharged through the diode 18 and the open transistor 16. The gate potential of the switching MOS transistor 19 becomes higher than the source potential, the transistor is opened and held in this state by the voltage on the input capacitance 2 in the pauses between the pulses.

At the end of the input signal, the device returns to its original state.

Thus, the electronic relay provides switching of the load in accordance with the input signal, however, in comparison with the external one, it has a simpler circuit design.

Claims (1)

The invention is an electronic relay containing a pulse generator, a MOS transistor, the gate of which is connected to the output of the pulse generator, and the source is connected to the first power supply bus, the inverter whose input is connected to the input bus, the first diode whose cathode is connected to the second bus power supply, switching MOS transistor, second and third diodes, first and second controlling MOS transistors and a transformer, the first output of the first winding of which is connected to the anode of the first diode and the drain of the MOS transistor, and the second winding is turned on The connection between the gate and source of the first MOSFET transistor, the anode of the second diode is connected to the gate of the first MOSFET transistor, and its cathode is connected to the gate of the switching MOS transistor and the drain of the second MOSFET transistor, the gate of which is connected to the anode of the third the diode, the cathode of which is connected to the drain of the first MOSFET transistor, the first output bus and the source of the switching MOS transistor, the drain of which is connected to the second output bus, characterized in that, with a simplification pulse, a third and even the transformer winding worm, the first and second keys, the first terminals of which are connected to the second power supply bus, the control inputs to the inverter output and input, respectively, the second outputs to the second terminals of the first and third transformer windings, respectively, the first output of the third winding is connected to the first the output of the first winding, and the fourth winding is connected between the gate and the drain of the second MOSFET transistor. Rig / J UofrM. P FIG. 2