RU211320U1 - Transistor reverser - Google Patents

Abstract

The utility model relates to switching devices and can be used for reverse switching of currents in the load. The technical result of the claimed utility model is to increase reliability by combining the bases of all transistors into one control circuit and to exclude a short circuit in the power section of the transistor reverser circuit even if control pulses are accidentally applied to the optocouplers simultaneously. The transistor reverser contains four transistors, two of which are npn conductivity transistors and two other pnp conductivity transistors, the first pnp conductivity transistor and the second npn conductivity transistor are connected by collectors and connected to one load input, as well as two optocouplers and four resistors. The third and fourth npn and pnp conductivity transistors, respectively, are connected by emitters and connected to the second load input, the emitter of the first p-np conductivity transistor and the collector of the third npn conductivity transistor are connected to the positive of the constant power supply voltage, and the second npn conductivity transistor is connected to the emitter and the fourth transistor pnp conductivity collector connected to the minus of the constant power supply voltage. The base of the first transistor is connected to one of the terminals of the first resistor, the base of the second transistor is connected to one of the terminals of the second resistor, the base of the third transistor is connected to one of the terminals of the third resistor, the base of the fourth transistor is connected to one of the terminals of the fourth resistor. The second terminal of the first resistor, the second terminal of the second resistor, the second terminal of the third resistor and the second terminal of the fourth resistor are connected and connected to a common point, which is connected to the anode and cathode of the photodiodes, respectively, of the first and second optocouplers connected in series to open the corresponding transistors. The photodiode of the first optocoupler is connected by the cathode to the plus of the constant power supply voltage, and the photodiode of the second optocoupler is connected by the anode to the minus of the constant power supply voltage. The reliability of the device is increased by combining the bases of all transistors into one control circuit when using pairs of transistors of opposite conductivity, as a result of which the control signal unlocks transistors of only one conductivity, with automatic reliable locking of transistors of opposite conductivity, and a short circuit of the power part of the circuit is also eliminated in case of accidental simultaneous supply of control signals. pulses to optocouplers. 2 ill.

Description

The utility model relates to electrical engineering, namely to switching devices and can be used for reverse switching of currents in the load.

A reversible four-pole device is known, containing two relay contacts B1 and B2, two relay contacts H1 and H2 and an inductive load in the form of an armature winding of a DC motor. When contacts B1 and B2 are closed, the current flows through the armature winding of the motor (load) in the forward direction. When contacts H1 and H2 are closed and contacts B1 and B2 are opened, the armature winding of the motor (load) is reversibly connected, the current flows in the opposite direction during this connection (Vishnevsky S.N. Characteristics of the motor in the electric drive [Text]. - 6th ed. , Rev. - Moscow: Energy. 1977. - S. 84. Fig. 2-22).

The described device has the following disadvantages: the appearance of electric arcs at the moment of opening the contact group, the relatively long switching time caused by the mechanical closing of the contact group.

The closest in technical essence to the proposed utility model (prototype) is a reversible transistor bridge made on semiconductor switches, which are four transistors, two of which are p-n-p conductivity transistors, the other two are n-p-n conductivity. Transistors of n-p-n conductivity are connected by emitters and connected to the minus of the constant power supply voltage, while the transistors are connected to the load, as the other two transistors of the reverse transistor bridge, p-n-p conductivity transistors are used, connected by emitters and connected to the plus of the constant power supply voltage. In this case, the collectors of transistors of opposite conductivity are combined in pairs, with one pair connected to the first load input, and the other pair connected to the second load input. The bases of n-p-n transistors of conductivity are connected through resistances to the minus of the constant power supply voltage for reliable blocking of n-p-n transistors of conductivity. The bases of the p-n-p transistors are connected through resistances to the positive of the constant power supply voltage for reliable blocking of the p-n-p transistors. The bases of transistors of different conductivity located opposite diagonally are connected by means of optocouplers to open the corresponding transistors. (RU 185925 U1 IPC H02K 47/12 (2006.01), H02M 7/162 (2006.01) dated 12/25/2018)

The disadvantage of this device is a reduced degree of reliability due to a possible short circuit of the power section of the transistor reverser circuit due to incorrect (simultaneous) inclusion of optocouplers.

The technical problem, the solution of which is provided in the implementation of the utility model, is to increase the reliability by combining the bases of all transistors into one control circuit and to exclude a short circuit of the power part of the transistor reverser circuit, even if control pulses are accidentally applied to the optocouplers simultaneously.

The solution to this technical problem is achieved by the fact that in a transistor reverser containing four transistors, two of which are transistors of n-p-n conductivity and two other transistors of p-n-p conductivity, the first transistor of p-n-p conductivity and the second transistor of n-p-n conductivity are connected by collectors and connected to one load input , as well as two optocouplers and four resistors, according to the utility model, the third and fourth transistors n-p-n and p-n-p conductivity, respectively, are connected by emitters and connected to the second input of the load, the emitter of the first transistor p-n-p conductivity and the collector of the third transistor n-p-n conductivity are connected to the positive constant power supply voltage, and the second transistor n-p-n conductivity by the emitter and the fourth transistor p-n-p conductivity by the collector are connected to the minus of the constant power supply voltage. The base of the first transistor is connected to one of the terminals of the first resistor, the base of the second transistor is connected to one of the terminals of the second resistor, the base of the third transistor is connected to one of the terminals of the third resistor, the base of the fourth transistor is connected to one of the terminals of the fourth resistor, the second terminal of the first resistor, the second the output of the second resistor, the second output of the third resistor and the second output of the fourth resistor are connected and connected to a common point, which is connected to the anode and cathode of the photodiodes, respectively, of the first and second optocouplers connected in series to open the respective transistors. The photodiode of the first optocoupler is connected by the cathode to the plus of the constant power supply voltage, and the photodiode of the second optocoupler is connected by the anode to the minus of the constant power supply voltage.

The increase in the reliability of the device is due to the fact that the bases of all transistors are connected in one control circuit, while pairs of transistors of different conductivity are used, as a result of which the control signal unlocks transistors of only one conductivity with automatic reliable locking of transistors of opposite conductivity.

The proposed utility model is illustrated by drawings, where in Fig. 1 shows a diagram of a transistor reverser; in fig. 2 shows the clock diagram of the operation of the transistor reverser.

In addition, the following symbols are used in the drawings:

VT1, VT4 - transistors p-n-p conductivity;

VT2, VT3 - transistors n-p-n conductivity;

R1, R2, R3, R4 - resistance;

Rn - load resistance;

VD1, VD2 - optocouplers;

"-" - minus the constant power voltage;

"+" - plus constant power voltage;

t1, t2, t3, t4, t5, t6 - switching times;

a straight line with an arrow shows the forward direction of the current in the load;

the dotted line with an arrow shows the reverse direction of the current in the load.

An example of a transistor reverser is shown in Fig. 1. The transistor reverser contains four transistors: transistor 1 (VT1) of p-n-p conductivity, connected to the plus of the constant power supply voltage by the emitter, and transistor 2 (VT2) of n-p-n conductivity, connected to the minus of the constant power supply voltage by the emitter, transistor 3 ( VT3) n-p-n conductivity, connected to the plus of the constant power supply voltage by the collector, and transistor 4 (VT4) p-n-p conductivity, connected to the minus of the constant power supply voltage by the collector.

The bases of all four transistors 1 (VT1) p-n-p conductivity, 2 (VT2) n-p-n conductivity, 3 (VT3) n-p-n conductivity and 4 (VT4) p-n-p conductivity through resistances 5 (R1), 6 (R2), 7 (R3) and 8 ( R4), respectively, are connected to a common point 9 of two optocouplers connected in series. The common point 9 is connected to the anode of the photodiode of the optocoupler 10 (VD1), the cathode of which is connected to the positive of the constant power supply voltage, and the common point 9 is connected to the cathode of the photodiode of the optocoupler 11 (VD2), connected by the anode to the minus of the constant power supply voltage.

The collectors of transistor 1 (VT1) p-n-p conductivity and transistor 2 (VT2) n-p-n conductivity are combined and connected to the first input 12 of the load 13 (Rn). The emitters of the transistor 3 (VT3) n-p-n conductivity and transistor 4 (VT4) p-n-p conductivity are combined and connected to the second input 14 of the load 13 (Rn).

The operation of the transistor reverser is as follows.

For current to flow through the load resistor in the forward direction, indicated by the solid line with an arrow in FIG. 1, at time t1 (FIG. 2) a signal is applied to the optocoupler 10 (VD1). A positive signal unlocks the n-p-n transistors, namely transistors 2 (VT2) and 3 (VT3), while the p-n-p transistors are securely locked, namely transistors 1 (VT1) and 4 (VT4). Since transistors 2 (VT2) and 3 (VT3) are open, the collector current begins to flow in the following direction through the load 13 (Rn): plus a constant power supply voltage, the collector of transistor 3 (VT3), the emitter of transistor 3 (VT3), input 14 load 13 (Rн), load 13 (Rн), collector of transistor 2 (VT2), emitter of transistor 2 (VT2), minus DC power supply voltage. At time t2 (Fig. 2), the control signal to the optocoupler 10 (VD1) stops and transistors 3 (VT2) and 2 (VT3) close. For the passage of current in the backward direction through the load 13 (Rn), indicated by a dotted line with an arrow (Fig. 1), at the time t3 (Fig. 2) a signal is applied to the optocoupler 11 (VD2). A negative signal unlocks the p-n-p conductivity transistors, namely transistors 1 (VT1) and 4 (VT4), while the n-p-n conductivity transistors are securely locked, namely transistors 2 (VT2) and 3 (VT3). Since transistors 1 (VT1) and 4 (VT4) are open, the collector current begins to flow along the following path: plus a constant power supply voltage, emitter of transistor 1 (VT1), collector of transistor 1 (VT1), load input 12 13 (Rn), load 13 (Rn), emitter of transistor 4 (VT4). the collector of transistor 4 (VT4), minus the constant power supply voltage. At time t4 (Fig. 2), the control signal to the optocoupler 11 (VD2) ceases, and transistors 1 (VT1) and 4 (VT4) close, then the cycle repeats. A short circuit of the power part of the circuit is excluded, since the current in this case will flow along the path: plus the power supply voltage, optocoupler 10 (VD1), common point 9, optocoupler 11 (VD2), minus the power supply voltage.

Thus, the proposed transistor reverser has an advantage over the reversible transistor bridge selected as a prototype, which consists in increasing the reliability of the device by combining the bases of all transistors into one control circuit when using pairs of transistors of opposite conductivity, as a result of which the control signal unlocks transistors of only one conductivity, with automatic reliable locking of transistors of opposite conductivity, as well as the exclusion of a short circuit of the power part of the circuit in case of accidental simultaneous supply of control pulses to optocouplers.

Claims (1)

A transistor reverser containing four transistors, two of which are transistors of n-p-n conductivity and two other transistors of p-n-p conductivity, and the first transistor of p-n-p conductivity and the second n-p-n conductivity are connected by collectors and connected to one load input, as well as two optocouplers and four resistors, characterized in that the third and fourth transistors of n-p-n and p-n-p conductivity, respectively, are connected by emitters and connected to the second load input, the emitter of the first transistor of p-n-p conductivity and the collector of the third transistor of n-p-n conductivity are connected to the plus of a constant power supply voltage, and the second transistor n-p-n conductivity by the emitter and the fourth transistor p-n-p conductivity by the collector are connected to the minus of the constant power supply voltage, the base of the first transistor is connected to one of the terminals of the first resistor, the base of the second transistor is connected to one of the terminals of the second resistor, base of the third transistor a is connected to one of the terminals of the third resistor, the base of the fourth transistor is connected to one of the terminals of the fourth resistor, the second terminal of the first resistor, the second terminal of the second resistor, the second terminal of the third resistor and the second terminal of the fourth resistor are combined and connected to a common point, which is connected to the anode and to the cathode of photodiodes, respectively, of the first and second optocouplers connected in series, to open the corresponding transistors, the photodiode of the first optocoupler is connected by the cathode to the plus of the constant power supply voltage, and the photodiode of the second optocoupler is connected by the anode to the minus of the constant power supply voltage.

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