High-voltage differential electrical isolation system for single-circuit bidirectional communication transmission

Abstract

The present invention relates to the field of communication technology, and in particular discloses a high-voltage difference electrical isolation system for single-circuit bidirectional communication transmission, comprising a high-voltage side device, a low-voltage side device and at least two groups of bidirectional communication transmission circuits, wherein the high-voltage side device is connected to one group of bidirectional communication transmission circuits, and the low-voltage side device is connected to the other group of bidirectional communication transmission circuits, and the bidirectional communication transmission circuits are interconnected through optical fibers, and the bidirectional communication transmission circuits comprise a first conversion unit that generates a first control signal according to a first data signal, or generates a second control signal according to a second data signal; an optical fiber transmitter outputs a first optical signal according to the first control signal, or outputs a second optical signal according to the second control signal; an optical fiber receiver is used to receive the second optical signal or the first optical signal; and a second conversion unit transmits the second data signal to a communication port of a low-voltage side device according to the second optical signal, or transmits the first data signal to the communication port of a high-voltage side device according to the first optical signal.

Description

Technical Field

[0001] The invention relates to the field of communication technology, and in particular to a high-voltage difference electrical isolation system for single-circuit bidirectional communication transmission. Background Art

[0002] In some electronic circuit designs, in order to better suppress noise interference and improve the electromagnetic compatibility of the system, strict electrical isolation is usually required between high-voltage equipment and low-voltage equipment to prevent the introduction of interference signals into the system. During normal operation, a mutual communication connection needs to be established between high-voltage equipment and low-voltage equipment to achieve normal two-way data transmission. However, due to the electrical isolation between high-voltage equipment and low-voltage equipment, the existing electrical system at both ends of the high-voltage difference isolation has the problem that a single circuit cannot be compatible with sending and receiving. Summary of the invention

[0003] Based on this, it is necessary to provide a high-voltage difference electrical isolation system with single-circuit bidirectional communication transmission to address the problem that a single circuit of the existing electrical systems at both ends of high-voltage difference isolation cannot be compatible with sending and receiving.

[0004] A high-voltage difference electrical isolation system for single-circuit bidirectional communication transmission comprises a high-voltage side device, a low-voltage side device and at least two groups of bidirectional communication transmission circuits, wherein the high-voltage side device is connected to one group of the bidirectional communication transmission circuits, and the low-voltage side device is connected to the other group of the bidirectional communication transmission circuits, and at least two groups of the bidirectional communication transmission circuits are mutually connected through optical fibers, wherein the bidirectional communication transmission circuit comprises a first conversion unit, an optical fiber transmitter, an optical fiber receiver and a second conversion unit, wherein the first conversion unit is connected to a communication port of the low-voltage side device or a communication port of the high-voltage side device, and is used to generate a first control signal according to a first data signal output by the low-voltage side device, or to generate a second control signal according to a second data signal output by the high-voltage side device; the optical fiber transmitter is connected to the first conversion unit, and is used to output a first optical signal according to the first control signal, or to output a second optical signal according to the second control signal; the optical fiber receiver is used to receive the second optical signal or the first optical signal; and the second conversion unit is connected to the optical fiber receiver, and is used to transmit the second data signal to the communication port of the low-voltage side device according to the second optical signal, or to transmit the first data signal to the communication port of the high-voltage side device according to the first optical signal.

[0005] In one embodiment, the first conversion unit includes a first switch unit, which is used to turn on or off the connection between the first working power supply and the optical fiber transmitter according to the first data signal output by the low-voltage side device, or to turn on or off the connection between the second working power supply and the optical fiber transmitter according to the second data signal output by the high-voltage side device; and a Schmitt trigger, which is used to convert the first data signal output by the low-voltage side device into the first control signal, or to convert the second data signal output by the high-voltage side device into the second control signal.

[0006] In one embodiment, the optical fiber transmitter includes a light emitting diode, the first switching unit includes a first transistor, a first resistor, a second resistor and a third resistor, the first electrode of the first transistor is connected to a first working power supply or a second working power supply, the gate of the first transistor is connected to a first end of the first resistor, the second end of the first resistor is connected to a communication port of the low-voltage side device or a communication port of the high-voltage side device, the second electrode of the first transistor is respectively connected to a first end of the second resistor and a first end of the third resistor, the second end of the second resistor is connected to an anode of the light emitting diode, and the second end of the third resistor and a cathode of the light emitting diode are both grounded.

[0007] In one embodiment, the Schmitt trigger includes a first diode, a second transistor, a third transistor, a fourth resistor, a fifth resistor, a sixth resistor and a seventh resistor, the cathode of the first diode is connected to the communication port of the low-voltage side device or the communication port of the high-voltage side device, the cathode of the first diode is also connected to the first end of the fourth resistor, the anode of the first diode is respectively connected to the second end of the fourth resistor, the first end of the fifth resistor and the first end of the sixth resistor, the second end of the fifth resistor is connected to the gate of the second transistor, the first electrode of the second transistor is connected to the anode of the light-emitting diode, the second electrode of the second transistor is grounded, the second end of the sixth resistor is connected to the first electrode of the third transistor, the gate of the third transistor is connected to the first end of the seventh resistor, the second electrode of the third transistor is grounded, and the second end of the seventh resistor is connected to the anode of the light-emitting diode.

[0008] In one embodiment, the first transistor is a P-type transistor, the second transistor and the third transistor are both N-type transistors, and a turn-on threshold voltage of the second transistor is greater than a turn-on threshold voltage of the third transistor.

[0009] In one embodiment, the optical fiber receiver includes a photoelectric conversion circuit, the photoelectric conversion circuit includes a first end and a second end, the second conversion unit includes a fourth transistor, a fifth transistor, a sixth transistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor and a twelfth resistor, the first end of the eighth resistor is connected to the first working power supply or the second working power supply, the first end of the eighth resistor is also connected to the first end of the photoelectric conversion circuit, the second end of the eighth resistor is connected to the second end of the photoelectric conversion circuit, the second end of the photoelectric conversion circuit is also respectively connected to the first end of the ninth resistor and the first end of the tenth resistor, the second end of the ninth resistor is connected to the gate of the fourth transistor, the first electrode of the fourth transistor is connected to the first working power supply or the second working power supply, the second electrode of the fourth transistor is respectively connected to the first end of the eleventh resistor and the first end of the twelfth resistor, the second end of the eleventh resistor is grounded, the second end of the twelfth resistor is respectively connected to the first electrode of the fifth transistor and the gate of the sixth transistor, the second end of the tenth resistor is connected to the gate of the fifth transistor, the first electrode of the sixth transistor is connected to the communication port of the low-voltage side device or the communication port of the high-voltage side device, and the second electrode of the fifth transistor and the second electrode of the sixth transistor are both grounded.

[0010] In one embodiment, the fourth transistor is a P-type transistor, and the fifth transistor and the sixth transistor are both N-type transistors.

[0011] In one of the embodiments, the bidirectional communication transmission circuit also includes a second switching unit, which is used to turn on or off the connection between the first working power supply and the first conversion unit according to the signal at the output end of the optical fiber receiver, or to turn on or off the connection between the second working power supply and the first conversion unit according to the signal at the output end of the optical fiber receiver.

[0012] In one embodiment, the second switching unit includes a seventh transistor, a thirteenth resistor, a fourteenth resistor and a first capacitor, the first electrode of the seventh transistor is respectively connected to the first end of the first capacitor and the first end of the thirteenth resistor, the first electrode of the seventh transistor is also connected to the first working power supply or the second working power supply, the gate of the seventh transistor is respectively connected to the second end of the first capacitor and the first end of the fourteenth resistor, the second electrode of the seventh transistor is connected to the first conversion unit, the second end of the thirteenth resistor is connected to the communication port of the low-voltage side device or the communication port of the high-voltage side device, and the second end of the fourteenth resistor is connected to the second conversion unit.

[0013] In one embodiment, the seventh transistor is a P-type transistor.

[0014] In the above-mentioned single-circuit bidirectional communication transmission high-voltage difference electrical isolation system, the high-voltage side device and the low-voltage side device are respectively connected to the bidirectional communication transmission circuit, and the bidirectional communication transmission circuits are connected to each other through optical fibers. During communication, the device on one side converts the data signal into an optical signal through the bidirectional communication transmission circuit, and the bidirectional communication transmission circuit of the device on the other side can realize the reception and conversion of the optical signal. That is, the bidirectional communication transmission circuit can realize bidirectional communication with the single-side device, solving the problem that the single circuit isolated by optical fiber is not compatible with sending and receiving. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the implementation methods of this specification or the technical solutions in the prior art, the drawings required for use in the implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some implementation methods recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0016] Figure 1 This is a structural schematic diagram of a high-voltage difference electrical isolation system for single-circuit bidirectional communication transmission in one of the embodiments of the present application;

[0017] Figure 2 This is a structural schematic diagram of a high-voltage difference electrical isolation system for single-circuit bidirectional communication transmission in another embodiment of the present application;

[0018] Figure 3 This is a circuit diagram of a high-voltage difference electrical isolation system for single-circuit bidirectional communication transmission in one of the embodiments of the present application. DETAILED DESCRIPTION

[0019] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to understand the disclosure of the present invention more thoroughly and comprehensively.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0021] Figure 1This is a structural schematic diagram of a high-voltage difference electrical isolation system for bidirectional communication transmission of a single circuit in one of the embodiments of the present application. In one of the embodiments, the high-voltage difference electrical isolation system for bidirectional communication transmission of a single circuit may include a high-voltage side device 10, a low-voltage side device 20, and at least two groups of bidirectional communication transmission circuits. Among them, the high-voltage difference electrical isolation system may include one or more groups of high-voltage side devices 10 and / or low-voltage side devices 20. For example, the high-voltage side device 10 may be a main control device, and the low-voltage side device 20 may be an external device that receives the main control device. The high-voltage side device 10 is connected to one or more groups of bidirectional communication transmission circuits, and the low-voltage side device 20 is connected to one or more groups of bidirectional communication transmission circuits. Each group of bidirectional communication transmission circuits may be interconnected through an optical fiber 200.

[0022] In this embodiment, in order to distinguish the bidirectional communication transmission circuit, the bidirectional communication transmission circuit connected to the high-voltage side device 10 can be marked as a bidirectional communication transmission circuit 100A, and the bidirectional communication transmission circuit connected to the low-voltage side device 20 can be marked as a bidirectional communication transmission circuit 100B. Each group of bidirectional communication transmission circuits can include a first conversion unit 110, an optical fiber transmitter 120, an optical fiber receiver 130, and a second conversion unit 140. The first conversion unit 110 in the bidirectional communication transmission circuit 100B can be connected to the communication port of the low-voltage side device 20, and the first conversion unit 110 in the bidirectional communication transmission circuit 100B can generate a first control signal according to the first data signal output by the low-voltage side device 20.

[0023] The first conversion unit 110 in the bidirectional communication transmission circuit 100A can be connected to the communication port of the high-voltage side device 10 , and the first conversion unit 110 in the bidirectional communication transmission circuit 100A can generate a first control signal according to the first data signal output by the high-voltage side device 10 .

[0024] The optical fiber transmitter 120 may be connected to the first conversion unit 110 , and the optical fiber transmitter 120 may output a first optical signal according to a first control signal, or the optical fiber transmitter 120 may output a second optical signal according to a second control signal.

[0025] The optical fiber receiver 130 in the bidirectional communication transmission circuit 100A can be connected to the optical fiber transmitter 120 in the bidirectional communication transmission circuit 100B through the optical fiber 200, and the optical fiber receiver 130 in the bidirectional communication transmission circuit 100B can be connected to the optical fiber transmitter 120 in the bidirectional communication transmission circuit 100A through the optical fiber 200. The optical fiber receiver 130 can be used to receive the second optical signal or the first optical signal.

[0026] The second conversion unit 140 can be connected to the optical fiber receiver 130. The second conversion unit 140 in the bidirectional communication transmission circuit 100B can transmit the second data signal to the communication port of the low-voltage side device 20 according to the second optical signal. The second conversion unit 140 in the bidirectional communication transmission circuit 100A can transmit the first data signal to the communication port of the high-voltage side device 10 according to the first optical signal.

[0027] In the above-mentioned single-circuit bidirectional communication transmission high-voltage difference electrical isolation system, the high-voltage side device 10 and the low-voltage side device 20 are respectively connected to the bidirectional communication transmission circuit, and the bidirectional communication transmission circuits are connected to each other through the optical fiber 200. During communication, the device on one side converts the data signal into an optical signal through the bidirectional communication transmission circuit, and the bidirectional communication transmission circuit of the device on the other side can realize the reception and conversion of the optical signal. That is, the bidirectional communication transmission circuit can realize bidirectional communication for the single-side device, solving the problem that the single circuit of optical fiber isolation is incompatible with sending and receiving. The electrical devices at both ends of the high-voltage difference isolation can realize bidirectional communication through two single-mode optical fibers using the bidirectional communication transmission circuit. For example, the SDA (Serial Data) of IIC (Inter-Integrated Circuit) can be sent and received through the bidirectional communication transmission circuit.

[0028] Figure 2 This is a structural schematic diagram of a high-voltage difference electrical isolation system for single-circuit bidirectional communication transmission in another embodiment of the present application. In one embodiment, the first conversion unit 110 may include a first switch unit 111 and a Schmitt trigger 112 .

[0029] The first switch unit 111 in the bidirectional communication transmission circuit 100B can be connected between the first working power supply and the optical fiber transmitter 120 in the bidirectional communication transmission circuit 100B. The first switch unit 111 in the bidirectional communication transmission circuit 100B can be used to turn on or off the connection between the first working power supply and the optical fiber transmitter 120 according to the first data signal output by the low-voltage side device 20.

[0030] The first switch unit 111 in the bidirectional communication transmission circuit 100A can be connected between the second working power supply and the optical fiber transmitter 120 in the bidirectional communication transmission circuit 100A. The first switch unit 111 in the bidirectional communication transmission circuit 100A can be used to turn on or off the connection between the second working power supply and the optical fiber transmitter 120 according to the second data signal output by the high-voltage side device 10.

[0031] The Schmitt trigger 112 in the bidirectional communication transmission circuit 100B can be used to convert the first data signal output by the low-voltage side device 20 into a first control signal, and the Schmitt trigger 112 in the bidirectional communication transmission circuit 100A can be used to convert the second data signal output by the high-voltage side device 10 into a second control signal. In this embodiment, when irregular pulse signals with different amplitudes are applied to the input end of the Schmitt trigger 112, the Schmitt trigger 112 can select a pulse signal with an amplitude greater than a preset value for output, thereby realizing the triggering of the logic level.

[0032] Figure 3 This is a circuit diagram of a high-voltage difference electrical isolation system for bidirectional communication transmission in a single circuit in one embodiment of the present application. In one embodiment, the optical fiber transmitter 120 may include a light-emitting diode, and the light-emitting diode may include an anode and a cathode. Figure 3 The optical fiber transmitter U1 may include multiple interfaces, wherein when an external device is connected to interface 1 of the optical fiber transmitter, the anode of the light-emitting diode inside the optical fiber transmitter U1 can be connected, and when an external device is connected to interface 2 of the optical fiber transmitter, the cathode of the light-emitting diode inside the optical fiber transmitter U1 can be connected.

[0033] Figure 3 In the figure, L_GND is the 0V power ground on the low voltage side, L_5V is the first working power supply on the low voltage side, and the signal L_SDA is the open-drain I / O signal (Input / Output) transmitted by the communication port on the low voltage side. H_GND is the 0V power ground on the high voltage side, H_5V is the second working power supply on the high voltage side, and the signal H_SDA is the open-drain I / O signal transmitted by the communication port on the high voltage side. In this embodiment, the high level in the bidirectional communication transmission circuit 100A is close to the level of L_5V, and the low level is close to the level of L_GND; the high level in the bidirectional communication transmission circuit 100B is close to the level of H_5V, and the low level is close to the level of H_GND.

[0034] In the embodiments of the present disclosure, a transistor refers to a component including at least a gate, a drain, and a source. In the present disclosure, the first electrode of the transistor may be a drain, the second electrode may be a source, or the first electrode may be a source, and the second electrode may be a drain. In the case of using transistors with opposite polarities or the current direction changes during circuit operation, the functions of the "source" and "drain" are sometimes interchanged. In the embodiments of the present disclosure, the gate of all or part of the transistors may be used as a control electrode, and the first electrode and the second electrode may be interchangeable as needed.

[0035] The first switch unit 111 may include a first transistor Q1, a first resistor R1, a second resistor R2, and a third resistor R3. The first electrode of the first transistor Q1 in the bidirectional communication transmission circuit 100B may be connected to the first working power supply L_5V, the first electrode of the first transistor Q1 in the bidirectional communication transmission circuit 100A may be connected to the second working power supply H_5V, and the gate of the first transistor Q1 may be connected to the first end of the first resistor R1. The first resistor R1 may be used as a current limiting resistor of the first transistor Q1, and the first resistor R1 is used to limit the driving current of the first transistor Q1 to achieve current limiting protection for the first transistor Q1. The second end of the first resistor R1 in the bidirectional communication transmission circuit 100B may be connected to the communication port of the low-voltage side device 20, and the second end of the first resistor R1 in the bidirectional communication transmission circuit 100A may be connected to the communication port of the high-voltage side device 10.

[0036] The second electrode of the first transistor R1 can be connected to the first end of the second resistor R2 and the first end of the third resistor R3 respectively, and the second end of the second resistor R2 can be connected to the interface 1 of the optical fiber transmitter 120, that is, the second end of the second resistor R2 can be connected to the anode of the light emitting diode in the optical fiber transmitter 120. The second end of the third resistor R3 can be connected to the interface 2 of the optical fiber transmitter 120, that is, the second end of the third resistor R3 can be connected to the cathode of the light emitting diode in the optical fiber transmitter 120. In addition, the second end of the third resistor R3 and the cathode of the light emitting diode in the optical fiber transmitter 120 are both grounded.

[0037] In one embodiment, the Schmitt trigger 112 may include a first diode D1, a second transistor Q2, a third transistor Q3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6 and a seventh resistor R7. In this embodiment, the first diode D1 may be a Schottky diode.

[0038] The cathode of the first diode D1 in the bidirectional communication transmission circuit 100B can be connected to the communication port of the low-voltage side device 20, and the cathode of the first diode D1 in the bidirectional communication transmission circuit 100A can be connected to the communication port of the high-voltage side device 10. The cathode of the first diode D1 can also be connected to the first end of the fourth resistor R4. The anode of the first diode D1 can be connected to the second end of the fourth resistor R4, the first end of the fifth resistor R5, and the first end of the sixth resistor R6, respectively.

[0039] The second end of the fifth resistor R5 can be connected to the gate of the second transistor Q2, and the fifth resistor R5 can be used as a current limiting resistor of the second transistor Q2. The fifth resistor R5 is used to limit the driving current of the second transistor Q2 to achieve current limiting protection for the second transistor Q2. The first electrode of the second transistor Q2 can be connected to the interface 1 of the optical fiber transmitter 120, that is, the first electrode of the second transistor Q2 can be connected to the anode of the light emitting diode in the optical fiber transmitter 120. The second electrode of the second transistor Q2 can be grounded.

[0040] The second end of the sixth resistor R6 can be connected to the first electrode of the third transistor Q3, the gate of the third transistor Q3 can be connected to the first end of the seventh resistor R7, the seventh resistor R7 can be used as a current limiting resistor of the third transistor Q3, and the seventh resistor R7 is used to limit the driving current of the third transistor Q3 to achieve current limiting protection for the third transistor Q3. The second electrode of the third transistor Q3 can be grounded. The second end of the seventh resistor R7 can be connected to the interface 2 of the optical fiber transmitter 120, that is, the second end of the seventh resistor R7 can be connected to the cathode of the light emitting diode in the optical fiber transmitter 120.

[0041] In one embodiment, the first transistor Q1 is a P-type transistor, and the second transistor Q2 and the third transistor Q3 are both N-type transistors. That is, the first transistor Q1 is turned on according to a low level and turned off according to a high level, and the second transistor Q2 and the third transistor Q3 are turned on according to a high level and turned off according to a low level. In this embodiment, the turn-on threshold voltage Vgs of the second transistor Q2 is greater than the turn-on threshold voltage Vgs of the third transistor Q3. For example, the turn-on threshold voltage Vgs of the second transistor Q2 can be about 1.7V, and the turn-on threshold voltage Vgs of the third transistor Q3 can be about 0.6V. By making the turn-on threshold voltage Vgs of the second transistor Q2 greater than the turn-on threshold voltage Vgs of the third transistor Q3, the third transistor Q3 can be turned on later than the second transistor Q2, so that the first diode D1, the second transistor Q2, the third transistor Q3, the fourth resistor R4 and the sixth resistor R6 can form a hysteresis trigger, that is, a Schmitt loop, thereby realizing the Schmitt trigger of the logic level, so that the rising edge trigger is about 3.5V and the falling edge trigger is about 1.5V.

[0042] In one embodiment, the optical fiber receiver 130 may include a photoelectric conversion circuit 131, and the photoelectric conversion circuit 131 may include a first end and a second end. In this embodiment, the first end of the photoelectric conversion circuit 131 may be a working voltage input port VCC, and the second end of the photoelectric conversion circuit 131 may be an output port VO of the photoelectric conversion circuit 131. Figure 3As shown, the fiber optic receiver 130 may include multiple interfaces, interface 1 of the fiber optic receiver 130 may be connected to a first end of the photoelectric conversion circuit 131 , and interface 2 of the fiber optic receiver 130 may be connected to a second end of the photoelectric conversion circuit 131 .

[0043] The second conversion unit 140 may include a fourth transistor Q4 , a fifth transistor Q5 , a sixth transistor Q6 , an eighth resistor R8 , a ninth resistor R9 , a tenth resistor R10 , an eleventh resistor R11 , and a twelfth resistor R12 .

[0044] The first end of the eighth resistor R8 in the two-way communication transmission circuit 100B can be connected to the first working power supply L_5V, and the first end of the eighth resistor R8 in the two-way communication transmission circuit 100A can be connected to the second working power supply H_5V. The first end of the eighth resistor R8 can also be connected to the interface 1 of the optical fiber receiver 130, that is, the first end of the eighth resistor R8 can also be connected to the first end of the photoelectric conversion circuit 131 in the optical fiber receiver 130. The second end of the eighth resistor R8 can be connected to the interface 2 of the optical fiber receiver 130, that is, the second end of the eighth resistor R8 can be connected to the second end of the photoelectric conversion circuit 131 in the optical fiber receiver 130.

[0045] The interface 2 of the optical fiber receiver 130 can also be connected to the first end of the ninth resistor R9 and the first end of the tenth resistor R10, that is, the second end of the photoelectric conversion circuit 131 can also be connected to the first end of the ninth resistor R9 and the first end of the tenth resistor R10, respectively. The second end of the ninth resistor R9 is connected to the gate of the fourth transistor Q4, and the ninth resistor R9 can be used as a current limiting resistor of the fourth transistor Q4. The ninth resistor R9 is used to limit the driving current of the fourth transistor Q4 to achieve current limiting protection for the fourth transistor Q4.

[0046] The first electrode of the fourth transistor Q4 in the bidirectional communication transmission circuit 100B can be connected to the first working power supply L_5V, and the first electrode of the fourth transistor Q4 in the bidirectional communication transmission circuit 100A can be connected to the second working power supply H_5V. The second electrode of the fourth transistor Q4 can be connected to the first end of the eleventh resistor R11 and the first end of the twelfth resistor R12 respectively, and the second end of the eleventh resistor R11 is grounded. The second end of the twelfth resistor R12 can be connected to the first electrode of the fifth transistor Q5 and the gate of the sixth transistor Q6 respectively, and the twelfth resistor R12 can be used as a current limiting resistor of the sixth transistor Q6, and the twelfth resistor R12 is used to limit the driving current of the sixth transistor Q6 to achieve current limiting protection for the sixth transistor Q6.

[0047] The second end of the tenth resistor R10 can be connected to the gate of the fifth transistor Q5, and the tenth resistor R10 can be used as a current limiting resistor of the fifth transistor Q5. The tenth resistor R10 is used to limit the driving current of the fifth transistor Q5 to achieve current limiting protection for the fifth transistor Q5. The first electrode of the sixth transistor Q6 in the bidirectional communication transmission circuit 100B can be connected to the communication port of the low-voltage side device 20, and the first electrode of the sixth transistor Q6 in the bidirectional communication transmission circuit 100A can be connected to the communication port of the high-voltage side device 10, and the second electrode of the fifth transistor Q5 and the second electrode of the sixth transistor Q6 can both be grounded.

[0048] In one embodiment, the fourth transistor Q4 is a P-type transistor, and the fifth transistor Q5 and the sixth transistor Q6 are both N-type transistors. That is, the fourth transistor Q4 is turned on according to a low level and turned off according to a high level, and the fifth transistor Q5 and the sixth transistor Q6 are turned on according to a high level and turned off according to a low level. In this embodiment, the turn-on threshold voltage Vgs of the fifth transistor Q5 is the same as the turn-on threshold voltage Vgs of the sixth transistor Q6. For example, the turn-on threshold voltage Vgs of the fifth transistor Q5 and the turn-on threshold voltage of the sixth transistor Q6 can both be about 1.7V.

[0049] See also Figure 2 In one embodiment, the bidirectional communication transmission circuit may further include a second switch unit 150. The second switch unit 150 may be connected to the optical fiber receiver 130. The second switch unit 150 in the bidirectional communication transmission circuit 100B may be connected between the first conversion unit 110 and the first working power supply L_5V, and the second switch unit 150 in the bidirectional communication transmission circuit 100A may be connected between the first conversion unit 110 and the second working power supply H_5V. The second switch unit 150 in the bidirectional communication transmission circuit 100B may turn on or off the connection between the first working power supply L_5V and the first conversion unit 110 according to the signal at the output end of the optical fiber receiver 130 in the bidirectional communication transmission circuit 100B; the second switch unit 150 in the bidirectional communication transmission circuit 100A may turn on or off the connection between the second working power supply H_5V and the first conversion unit 110 according to the signal at the output end of the optical fiber receiver 130 in the bidirectional communication transmission circuit 100A.

[0050] In one embodiment, the second switch unit 150 may include a seventh transistor Q7, a thirteenth resistor R13, a fourteenth resistor R14 and a first capacitor C1.

[0051] The first electrode of the seventh transistor Q7 can be connected to the first end of the first capacitor C1 and the first end of the thirteenth resistor R13 respectively. The first electrode of the seventh transistor Q7 in the bidirectional communication transmission circuit 100B can also be connected to the first working power supply L_5V, and the first electrode of the seventh transistor Q7 in the bidirectional communication transmission circuit 100A can also be connected to the second working power supply H_5V.

[0052] The gate of the seventh transistor Q7 can be connected to the second end of the first capacitor C1 and the first end of the fourteenth resistor R14 respectively. The fourteenth resistor R14 can be used as a current limiting resistor of the seventh transistor Q7. The fourteenth resistor R14 is used to limit the driving current of the seventh transistor Q7 to achieve current limiting protection for the seventh transistor Q7.

[0053] The second pole of the seventh transistor Q7 can be connected to the first conversion unit 110. Specifically, the second pole of the seventh transistor Q7 can be connected to the first pole of the first transistor Q1. The second end of the thirteenth resistor R13 in the two-way communication transmission circuit 100B can be connected to the communication port of the low-voltage side device 20, and the second end of the thirteenth resistor R13 in the two-way communication transmission circuit 100A can be connected to the communication port of the high-voltage side device 10. The second end of the fourteenth resistor R14 can be connected to the second conversion unit 140. Specifically, the second end of the fourteenth resistor R14 can be connected to the second pole of the fourth transistor Q4 in the second conversion unit 140, the first end of the eleventh resistor R11, and the first end of the twelfth resistor R12.

[0054] In one embodiment, the seventh transistor Q7 is a P-type transistor, that is, the seventh transistor Q7 is turned on by a low level and turned off by a high level.

[0055] In this embodiment, Figure 3 Taking the single-circuit bidirectional communication transmission high-voltage difference electrical isolation system as an example, the working process of the low-voltage side device 20 sending a signal to the high-voltage side device 10 through the bidirectional communication transmission circuit 100B, and the high-voltage side device 10 receiving the signal through the bidirectional communication transmission circuit 100A is explained. The description is relatively specific and detailed, but it cannot be understood as a limitation on the scope of the invention patent.

[0056] Figure 3In the figure, U1 is the optical fiber transmitter 120 in the two-way communication transmission circuit 100B. When transmitting a signal, the forward voltage difference of the light-emitting diode in the optical fiber transmitter 120 is about 1.6V; U2 is the optical fiber receiver 130 in the two-way communication transmission circuit 100B. In the two-way communication transmission circuit 100B on the low-voltage side, the first transistor Q1, the fourth transistor Q4, and the seventh transistor Q7 are PNP field effect transistors, and the turn-on threshold voltage Vgs is about -1.5V; the third transistor Q3, the fifth transistor Q5, and the sixth transistor Q6 are NPN field effect transistors, and the turn-on threshold voltage Vgs is about 1.7V; the second transistor Q2 is an NPN field effect transistor, and the turn-on threshold voltage Vgs is about 0.6V; the first resistor R1 to the fourteenth resistor R14 are all ordinary chips. The first capacitor C1 is an ordinary chip ceramic capacitor with a capacitance of 2.2nF; the first diode D1 is a Schottky diode with a forward voltage drop of about 0.2V.

[0057] The circuit structure design of the bidirectional communication transmission circuit 100A is the same as the circuit structure design of the bidirectional communication transmission circuit 100B. Figure 3 In order to distinguish the electronic devices in the two-way communication transmission circuits on different sides, the transistors in the two-way communication transmission circuit 100A are marked as Q8 to Q14, the resistors are marked as R15 to R28, the capacitor is marked as C2, and the diode is marked as D2. U3 is the optical fiber transmitter 120 in the two-way communication transmission circuit 100A. When transmitting a signal, the forward voltage difference of the light-emitting diode in the optical fiber transmitter 120 is about 1.6V; U4 is the optical fiber receiver 130 in the two-way communication transmission circuit 100A. Q8, Q11, and Q14 in the two-way communication transmission circuit 100A on the high-voltage side are PNP field-effect transistors, and the turn-on threshold voltage Vgs is about -1.5V;

[0058] Q10, Q12, and Q13 are NPN field effect transistors, and the turn-on threshold voltage Vgs is about 1.7V; Q9 is an NPN field effect transistor, and the turn-on threshold voltage Vgs is about 0.6V; the first resistor R15 to the fourteenth resistor R28 are all ordinary SMDs. C2 is an ordinary SMD ceramic capacitor with a capacitance of 2.2nF; D2 is a Schottky diode with a forward voltage drop of about 0.2V.

[0059] The fourth resistor R4, the sixth resistor R6, the second transistor Q2, the third transistor Q3, and the first diode D1 form a hysteresis-triggered Schmitt trigger, so that the rising edge is triggered at about 3.5V and the falling edge is triggered at about 1.5V.

[0060] L_GND is the 0V power ground on the low voltage side; L_5V is the first working power supply on the low voltage side; the signal L_SDA is the open-drain I / O signal transmitted by the communication port on the low voltage side, the high level is close to the level of L_5V, and the low level is close to the level of L_GND. H_GND is the 0V power ground on the high voltage side; H_5V is the second working power supply on the high voltage side; the signal H_SDA is the open-drain I / O signal transmitted by the communication port on the high voltage side, the high level is close to the level of H_5V, and the low level is close to the level of H_GND.

[0061] The signal L_SDA is at a high level in the idle state, the signal H_SDA is at a high level in the idle state, and the interface 2 of the optical fiber receiver U2 is also at a high level when in the idle state. Since the signal L_SDA is at a high level, the first transistor Q1 is cut off according to the voltage at the gate, the second transistor Q2 is turned on according to the voltage at the gate, and the third transistor Q3 is also cut off according to the voltage at the gate. At the same time, since the interface 2 of the optical fiber receiver U2 is also at a high level, the fourth transistor Q4 is cut off according to the voltage at the gate, so that the gate of the first transistor Q1 is grounded, that is, the potential at the gate of the first transistor Q1 is at a low level, and the first transistor Q1 is turned on according to the voltage at the gate.

[0062] Taking the low-voltage side device 20 transmitting a signal to the high-voltage side device 10 through the two-way communication transmission circuit 100B as an example, the working state of the two-way communication transmission circuit sending information is described. When the signal L_SDA at the communication interface of the low-voltage side device 20 is pulled down, when the signal L_SDA drops to about 3.5V, the first transistor Q1 is turned on according to the potential at the gate. When the signal L_SDA continues to drop to about 1.5V (due to the parasitic capacitance of the transistor, the potential at the gate of the second transistor Q2 is actually pulled down by the first capacitor D1. If the level of the signal L_SDA drops slowly, the second transistor Q2 is turned off when the signal L_SDA drops to about 1.7V), the second transistor Q2 is turned off. The level of the signal L_SDA is eventually pulled down to a low level. At the same time, since the second transistor Q2 is turned off, the potential at the gate of the third transistor Q3 increases, and the third transistor Q3 is turned on. At this time, the light emitting diode in the optical fiber transmitter U1 is lit, and the optical signal is transmitted to the optical fiber receiver U4 of the high-voltage side bidirectional communication transmission circuit 100A through the optical fiber 200.

[0063] When the signal L_SDA at the communication interface of the low-voltage side device 20 rises, since the third transistor Q3 is turned on, the drain of the third transistor Q3 is close to 0V. When the level of the signal L_SDA rises to about 3.5V (the gate of the second transistor Q2 is divided to about 1.7V), the first transistor Q1 is turned off. The second transistor Q2 is turned on and quickly turns off the light-emitting diode in the optical fiber transmitter U1, and the third transistor Q3 is also turned off at this time. The principle of transmitting the signal from the high-voltage side device 10 to the low-voltage side device 20 is the same as that of transmitting the signal from the low-voltage side device 20 to the high-voltage side device 10, which will not be repeated here.

[0064] Taking the example of the high-voltage side device 10 transmitting an optical signal to the bidirectional communication transmission circuit 100B of the low-voltage side device 20 through the optical fiber 200, the working state of the bidirectional communication transmission circuit receiving information is described. When the signal H_SDA at the communication interface of the high-voltage side device 10 is pulled low, the light-emitting diode in the optical fiber transmitter U3 emits an optical signal, and after the optical signal is transmitted to the optical fiber receiver U2 of the high-voltage side bidirectional communication transmission circuit 100B through the optical fiber 200, the photoelectric conversion circuit 131 in the optical fiber receiver U2 converts the optical signal into an electrical signal, and the output port VO of the photoelectric conversion circuit 131 outputs a low level.

[0065] Since the level of the interface 2 of the optical fiber receiver U2 is pulled down to a low level, the fourth transistor Q4 is turned on according to the voltage at the gate, and the fifth transistor Q5 is turned off according to the voltage at the gate. Since the fourth transistor Q4 is turned on, the +5V voltage of the second working power supply is transmitted to the gate of the sixth transistor Q6, and the sixth transistor Q6 is turned on according to the voltage at the gate. After the sixth transistor Q6 is turned on, the signal L_SDA at the communication port of the low-voltage side device 20 is pulled down to a low level.

[0066] When the signal H_SDA at the communication interface of the high-voltage side device 10 rises, and the light-emitting diode in the optical fiber transmitter U3 of the high-voltage side device 10 is turned off, the level of the interface 2 of the optical fiber receiver U2 in the low-voltage side device 20 begins to be pulled up by the eighth resistor R8, and when the level of the interface 2 of the optical fiber receiver U2 is pulled up to about 1.7V by the eighth resistor R8, the fifth transistor Q5 is turned on. After the fifth transistor Q5 is turned on, the sixth transistor Q6 is turned off, and the signal L_SDA at the communication port of the low-voltage side device 20 is pulled up to a high level by the thirteenth resistor R13.

[0067] When the eighth resistor R8 of the interface 2 of the optical fiber receiver U2 is pulled up to about 3.5V, the fourth transistor Q4 begins to be turned off. In the present embodiment, by adding a capacitor C1 of suitable capacitance between the gate and source of the seventh transistor Q7, C1 can delay the opening of the seventh transistor Q7 to prevent the low-level signal at the low-voltage side device 20 from being mistakenly transmitted to the high-voltage side device 10. When the signal H_SDA signal L_SDA at the communication interface of the high-voltage side device 10 eventually rises to a high level, the level of the interface 2 of the optical fiber receiver U2 will also eventually rise to a high level. That is, in this process, when the signal H_SDA at the communication interface of the high-voltage side device 10 rises from a low level of about 0V to about 3.5V, the high-level signal is synchronously transmitted from the high-voltage side device 10 to the low-voltage side device 20, so that the signal L_SDA signal at the communication interface of the low-voltage side device 20 is also eventually pulled up to a high level.

[0068] In the above process, when the signal L_SDA drops from a high level of about 5V to about 1.5V, the low level signal is transmitted from the low voltage side device 20 to the high voltage side device 10, and the signal H_SDA of the high voltage side device 10 is pulled down to a low level. At the same time, after the fourth transistor Q4 is turned on, the +5V voltage of the second working power supply is transmitted to the gate of the seventh transistor Q7, and the seventh transistor Q7 is cut off according to the voltage at the gate to prevent the optical fiber transmitter U1 from turning on, thereby preventing the low level of the low voltage side device 20 from being continuously transmitted to the high voltage side device 10. The principle of the high voltage side device 10 receiving the transmission signal of the low voltage side device 20 is the same as that of the low voltage side device 20 receiving the transmission signal of the high voltage side device 10, which will not be repeated here.

[0069] In an actual circuit, considering that the MOS tube has a short opening time and a long closing time, in response to this phenomenon, in an embodiment of the present application, components are added at appropriate positions to delay the opening process of the MOS tube, for example, capacitor C1 is used to delay the opening process of the seventh transistor Q7; components are added at appropriate positions to accelerate the closing process of the MOS tube, for example, diode D1 is used to accelerate the closing process of the second transistor Q2, and the fifth transistor Q5 is used to accelerate the closing process of the sixth transistor.

[0070] In the above-mentioned single-circuit bidirectional communication transmission high-voltage difference electrical isolation system, the high-voltage side device 10 and the low-voltage side device 20 are respectively connected to the bidirectional communication transmission circuit, and the bidirectional communication transmission circuits are interconnected through two single-mode optical fibers. The two single-mode optical fibers can realize mutual signal transmission and reception between the high and low voltage devices, solving the problem that the single circuit isolated by optical fiber is incompatible with transmission and reception.

[0071] It can be seen that the high-voltage difference electrical isolation system for the above-mentioned single-circuit bidirectional communication transmission, and at the same time, the transistors used in the high-voltage difference electrical isolation system for the above-mentioned single-circuit bidirectional communication transmission have the characteristics of low internal resistance, which can make the circuit achieve relatively small losses without increasing the consumption of the main circuit. At the same time, since the above-mentioned single-circuit bidirectional communication transmission high-voltage difference electrical isolation system can be built using discrete components, fewer components are used, and commonly used components such as transistors, voltage regulators, resistors, capacitors, etc. are used, it also has the advantage of low circuit cost.

[0072] In one embodiment, the resistance values ​​of the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, the eighth resistor R8, the ninth resistor R9, the tenth resistor R10, the eleventh resistor R11, the twelfth resistor R12, the thirteenth resistor R13 and the fourteenth resistor R14 can be adaptively designed according to different application requirements. Similarly, the capacitance of the first capacitor C1 and the first diode D1 can also be adaptively designed according to requirements.

[0073] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", "ideal embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0074] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0075] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. The above-mentioned embodiments only express several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A high-voltage difference electrical isolation system for single-circuit bidirectional communication transmission, characterized in that: The invention comprises a high-voltage side device, a low-voltage side device and at least two groups of bidirectional communication transmission circuits, wherein the high-voltage side device is connected to one group of the bidirectional communication transmission circuits, the low-voltage side device is connected to the other group of the bidirectional communication transmission circuits, at least two groups of the bidirectional communication transmission circuits are connected to each other through optical fibers, and the bidirectional communication transmission circuits comprise a first conversion unit, an optical fiber transmitter, an optical fiber receiver and a second conversion unit. The first conversion unit is connected to the communication port of the low-voltage side device or the communication port of the high-voltage side device, and is used to generate a first control signal according to a first data signal output by the low-voltage side device, or to generate a second control signal according to a second data signal output by the high-voltage side device; The first conversion unit comprises: a first switch unit, configured to switch on or off the connection between the first working power supply and the optical fiber transmitter according to the first data signal output by the low-voltage side device, or switch on or off the connection between the second working power supply and the optical fiber transmitter according to the second data signal output by the high-voltage side device; A Schmitt trigger, configured to convert the first data signal output by the low-voltage side device into the first control signal, or convert the second data signal output by the high-voltage side device into the second control signal; The optical fiber transmitter is connected to the first conversion unit and is used to output a first optical signal according to the first control signal, or to output a second optical signal according to the second control signal; The optical fiber transmitter includes a light emitting diode, the first switch unit includes a first transistor, a first resistor, a second resistor and a third resistor, The first electrode of the first transistor is connected to the first working power supply or the second working power supply, the gate of the first transistor is connected to the first end of the first resistor, the second end of the first resistor is connected to the communication port of the low-voltage side device or the communication port of the high-voltage side device, the second electrode of the first transistor is respectively connected to the first end of the second resistor and the first end of the third resistor, the second end of the second resistor is connected to the anode of the light-emitting diode, and the second end of the third resistor and the cathode of the light-emitting diode are both grounded; The optical fiber receiver is used to receive the second optical signal or the first optical signal; The optical fiber receiver includes a photoelectric conversion circuit, the photoelectric conversion circuit includes a first end and a second end, the second conversion unit includes a fourth transistor, a fifth transistor, a sixth transistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor and a twelfth resistor, The first end of the eighth resistor is connected to the first working power supply or the second working power supply, the first end of the eighth resistor is also connected to the first end of the photoelectric conversion circuit, the second end of the eighth resistor is connected to the second end of the photoelectric conversion circuit, the second end of the photoelectric conversion circuit is also respectively connected to the first end of the ninth resistor and the first end of the tenth resistor, the second end of the ninth resistor is connected to the gate of the fourth transistor, the first electrode of the fourth transistor is connected to the first working power supply or the second working power supply, the second electrode of the fourth transistor is respectively connected to the first end of the eleventh resistor and the first end of the twelfth resistor, the second end of the eleventh resistor is grounded, the second end of the twelfth resistor is respectively connected to the first electrode of the fifth transistor and the gate of the sixth transistor, the second end of the tenth resistor is connected to the gate of the fifth transistor, the first electrode of the sixth transistor is connected to the communication port of the low-voltage side device or the communication port of the high-voltage side device, and the second electrode of the fifth transistor and the second electrode of the sixth transistor are both grounded; The optical fiber receiver in the bidirectional communication transmission circuit connected to the high-voltage side device is connected to the optical fiber transmitter in the bidirectional communication transmission circuit connected to the low-voltage side device via the optical fiber, and the optical fiber transmitter in the bidirectional communication transmission circuit connected to the high-voltage side device is connected to the optical fiber receiver in the bidirectional communication transmission circuit connected to the low-voltage side device via the optical fiber; The second conversion unit is connected to the optical fiber receiver and is used to transmit the second data signal to the communication port of the low-voltage side device according to the second optical signal, or to transmit the first data signal to the communication port of the high-voltage side device according to the first optical signal; The Schmitt trigger includes a first diode, a second transistor, a third transistor, a fourth resistor, a fifth resistor, a sixth resistor and a seventh resistor. The cathode of the first diode is connected to the communication port of the low-voltage side device or the communication port of the high-voltage side device, the cathode of the first diode is also connected to the first end of the fourth resistor, the anode of the first diode is respectively connected to the second end of the fourth resistor, the first end of the fifth resistor and the first end of the sixth resistor, the second end of the fifth resistor is connected to the gate of the second transistor, the first electrode of the second transistor is connected to the anode of the light-emitting diode, the second electrode of the second transistor is grounded, the second end of the sixth resistor is connected to the first electrode of the third transistor, the gate of the third transistor is connected to the first end of the seventh resistor, the second electrode of the third transistor is grounded, and the second end of the seventh resistor is connected to the anode of the light-emitting diode; The two-way communication transmission circuit also includes: A second switch unit, used to switch on or off the connection between the first working power supply and the first conversion unit according to the signal at the output end of the optical fiber receiver, or switch on or off the connection between the second working power supply and the first conversion unit according to the signal at the output end of the optical fiber receiver; The second switch unit includes a seventh transistor, a thirteenth resistor, a fourteenth resistor and a first capacitor, The first electrode of the seventh transistor is respectively connected to the first end of the first capacitor and the first end of the thirteenth resistor, the first electrode of the seventh transistor is also connected to the first working power supply or the second working power supply, the gate of the seventh transistor is respectively connected to the second end of the first capacitor and the first end of the fourteenth resistor, the second electrode of the seventh transistor is connected to the first conversion unit, the second end of the thirteenth resistor is connected to the communication port of the low-voltage side device or the communication port of the high-voltage side device, and the second end of the fourteenth resistor is connected to the second conversion unit.

2. The high-voltage difference electrical isolation system for single-circuit bidirectional communication transmission according to claim 1 is characterized in that: The first transistor is a P-type transistor, the second transistor and the third transistor are both N-type transistors, and a turn-on threshold voltage of the second transistor is greater than a turn-on threshold voltage of the third transistor.

3. The high-voltage difference electrical isolation system for single-circuit bidirectional communication transmission according to claim 1, characterized in that: The fourth transistor is a P-type transistor, and the fifth transistor and the sixth transistor are both N-type transistors.

4. The high-voltage difference electrical isolation system for single-circuit bidirectional communication transmission according to claim 1, characterized in that: The seventh transistor is a P-type transistor.

Images