A communication isolation circuit and device

Abstract

The present application provides a communication isolation circuit and device, wherein the isolation circuit includes: a communication processor, including two communication signal terminals and a power supply terminal; two communication signal input terminals, each independently coupled to a communication signal terminal, for inputting a communication signal, a power supply, and an isolation module. The present application sets an isolation module, and when the power supply fails, disconnects the signal input from each communication signal input terminal to the corresponding communication signal terminal, thereby solving the problem of reduced reliability of redundant power supply caused by the non-isolation processing of traditional I2C communication signals, and simply and quickly realizes the mutual isolation and independent operation between power modules on the I2C communication line, avoiding the failure of communication of other power modules due to communication problems of a single power supply, and improving the reliability of the entire redundant work.

Description

Technical Field

[0001] The present application relates to the field of communication isolation circuits, and in particular to a communication isolation circuit and device. Background Art

[0002] The I2C (Inter-Integrated Circuit) bus is a two-wire serial bus used for communication in the electronics industry. It is mainly used for information transmission between microcontrollers and their peripheral devices. The I2C bus was created in the 1980s and was originally developed for audio and video equipment. Today, it is also used in switching power supplies and system servers, including the communication of single and multiple power module status. For example, administrators can query each power module to manage the system configuration or grasp the functional status of components, such as the output voltage of the power supply and the fan speed of the system. It can also monitor multiple parameters such as the input, output, fan speed and temperature of the switching power supply at any time, increasing the security of the system and the convenience of management.

[0003] The I2C bus is a serial bus consisting of a data line SDA and a clock SCL, which can send and receive data. It transmits data bidirectionally between the central processing unit (CPU) and the controlled integrated circuit (IC), and between ICs, with a maximum transmission rate of 100kbps. Various controlled circuits are connected in parallel on this bus, but just like a telephone, they can only work by dialing their own numbers, so each circuit and module has a unique address. During the transmission of information, each module circuit connected in parallel on the I2C bus is both a master controller (or controlled device) and a transmitter (or receiver), depending on the function it is to complete. The control signal sent by the CPU is divided into two parts: the address code and the control amount. The address code is used to select the address, that is, to connect the circuit to be controlled and determine the type of control; the control amount determines the type of adjustment (such as contrast, brightness, etc.) and the amount to be adjusted. In this way, although each control circuit is hung on the same bus, it is independent of each other and unrelated.

[0004] There are three types of signals in the I2C bus during data transmission: start signal, end signal and response signal.

[0005] Start signal: When SCL is high, SDA jumps from high to low and starts transmitting data.

[0006] End signal: When SCL is at a low level, SDA jumps from a low level to a high level, ending data transmission.

[0007] Response signal: After receiving 8-bit data, the IC that receives data sends a specific low-level pulse to the IC that sends data, indicating that the data has been received. After the CPU sends a signal to the controlled unit, it waits for the controlled unit to send a response signal. After receiving the response signal, the CPU determines whether to continue to transmit the signal based on the actual situation. If no response signal is received, it is determined that the controlled unit has a fault.

[0008] The I2C protocol uses a master / slave bidirectional communication. A device that sends data to the bus is defined as a transmitter, and a device that receives data is defined as a receiver. Both the master and slave devices can operate in both the receiving and transmitting states. The bus must be controlled by a master device (usually a microcontroller), which generates a serial clock (SCL) to control the direction of the bus and generate start and stop conditions. The data state on the SDA line can only change when SCL is low. During the period when SCL is high, the change of the SDA state is used to indicate the start and stop conditions.

[0009] In server power supplies, in order to better match system operation and flexibly adjust and control, the power supply end must use I2C communication to report and read information with the system and respond to corresponding instructions. However, if the power supply fails, it will affect the normal communication of the system. Summary of the invention

[0010] In order to solve at least one of the above problems, the present application provides a communication isolation circuit, comprising:

[0011] A communication processor, comprising two communication signal terminals and a power supply terminal;

[0012] Two communication signal input terminals are independently coupled to a communication signal terminal and are used to input a communication signal;

[0013] A power supply, respectively coupled to the two communication signal input terminals, the corresponding communication signal terminals and the power supply terminal; and

[0014] The isolation module is used to disconnect the signal input from each of the communication signal input ends to the corresponding communication signal terminal when the power supply fails.

[0015] In an optional embodiment, the isolation module includes a first isolation unit and a second isolation unit, each of the isolation units is coupled to the power supply and switches on a signal input channel from the communication signal input end to a corresponding communication signal terminal based on a high level generated by the power supply.

[0016] In an optional embodiment, the first isolation unit includes a first switch element and a first diode element, and the second isolation unit includes a second switch element and a second diode element;

[0017] The control end and input end of the first switch element are coupled to the power supply, and the output end thereof is coupled to the corresponding communication signal input end; the input end of the first diode element is coupled to the input end of the first switch element and to the corresponding communication signal terminal, and the output end thereof is coupled to the output end of the first switch element;

[0018] The control terminal and input terminal of the second switch element are coupled to a first node, and the output terminal thereof is coupled to the corresponding communication signal input terminal. The input terminal of the second diode element is coupled to the first node, and the output terminal thereof is coupled to the output terminal of the second switch element.

[0019] In an optional embodiment, the communication processor further includes a plurality of grounding terminals, each of which is coupled to a ground terminal and is coupled to a second node.

[0020] In an optional embodiment, it also includes:

[0021] A capacitor has one end coupled to the ground terminal and the other end coupled to the second node.

[0022] In an optional embodiment, the first diode element and / or the second diode element is a Schottky diode element.

[0023] In an optional embodiment, it also includes:

[0024] The first resistor is coupled between the first switch element and a corresponding power supply terminal.

[0025] In an optional embodiment, it also includes:

[0026] The second resistor is coupled between the first switch element and the corresponding communication signal input terminal.

[0027] In an optional embodiment, it also includes:

[0028] The third resistor is coupled between the first node and the power supply terminal.

[0029] In an optional embodiment, it also includes:

[0030] The fourth resistor is coupled between the second switch element and the corresponding communication signal input terminal.

[0031] In an optional embodiment, the communication isolation circuit is used for an I2C bus, the two communication signals include a data signal of the I2C bus and a clock signal of the I2C bus, and correspondingly, the communication signal terminal includes a data signal terminal and a clock signal terminal.

[0032] The present application further provides a communication isolation device, comprising the isolation circuit as described above.

[0033] The beneficial effects of this application are as follows:

[0034] The present application provides a communication isolation circuit and device. By setting an isolation module, when the power supply fails, the signal input from each communication signal input end to the corresponding communication signal terminal is disconnected, thereby solving the problem of reduced reliability of redundant power supply due to non-isolation of traditional I2C communication signals, and simply and quickly realizing mutual isolation and independent operation between power modules on the I2C communication line, avoiding the communication failure of other power modules due to communication problems of a single power supply, and improving the reliability of the entire redundant work. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0036] Figure 1 It is a structural diagram of a communication isolation circuit of the prior art provided by an embodiment of the present application.

[0037] Figure 2 It is a structural schematic diagram of a communication isolation circuit provided in another embodiment of the present application. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the embodiments of the present application are further described in detail below in conjunction with the accompanying drawings. Here, the illustrative embodiments of the present application and their descriptions are used to explain the present application, but are not intended to limit the present application. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined arbitrarily with each other.

[0039] In server power supplies, in order to better match system operation and flexibly adjust and control, the power supply end must use I2C communication to report and read information with the system and respond to corresponding instructions.

[0040] Traditional I2C communication line solutions such as Figure 1, SDA and SCL are pulled up to 3.3V by 10KΩ resistors R11 and R14 respectively, the internal microcontroller unit (MCU) is connected to the external SDA and SCL signals in series with a 22Ω anti-static resistor R12 and R13, the 3.3V power supply is coupled to the Vcc terminal of the MCU, and the ground terminal is connected to the capacitor C1 (the parameter of C1 in the figure is 1uF / 25V). However, the server power supply often involves multiple power modules in parallel. If the internal 3.3V power supply of a module power supply is abnormal, the other power modules will not be able to communicate normally with the system, which seriously reduces the reliability of the redundant power supply.

[0041] Based on this, the present application provides a communication isolation circuit, including:

[0042] A communication processor, comprising two communication signal terminals and a power supply terminal;

[0043] Two communication signal input terminals are independently coupled to a communication signal terminal and are used to input a communication signal;

[0044] A power supply, respectively coupled to the two communication signal input terminals, the corresponding communication signal terminals and the power supply terminal; and

[0045] The isolation module is used to disconnect the signal input from each of the communication signal input ends to the corresponding communication signal terminal when the power supply fails.

[0046] The present application provides a communication isolation circuit. By setting an isolation module, when the power supply fails, the signal input from each communication signal input end to the corresponding communication signal terminal is disconnected, thereby solving the problem of reduced reliability of redundant power supply due to non-isolation of traditional I2C communication signals, and simply and quickly realizing mutual isolation and independent operation between power modules on the I2C communication line, avoiding the communication failure of other power modules due to communication problems of a single power supply, and improving the reliability of the entire redundant work.

[0047] In the present application, it can be understood that the communication processor can be a commonly used processor in the art, such as a microprocessor MCU, etc., and the present application does not impose any limitation on this.

[0048] Combine the following Figure 2 This application is described in detail.

[0049] In the embodiment of the present application, the communication isolation circuit is used for the I2C bus, and the two communication signals include the data signal of the I2C bus and the clock signal of the I2C bus. Correspondingly, the communication signal terminal includes a data signal terminal and a clock signal terminal. Figure 2As shown, the two communication signals are SDA signal and SCL signal, wherein the SDA signal refers to the data signal line of the I2C bus, and the SCL signal refers to the clock signal, which will not be described in detail here.

[0050] It is understandable that the present application can be used not only for I2C bus, but also for other bus lines, etc., without limitation. The present application is developed based on the problems existing in the I2C bus. The present isolation circuit can be used for communication lines similar to the I2C bus, that is, lines that require two communication signals to complete signal interaction can be used for the present application, and the present application will not elaborate on them.

[0051] Those skilled in the art will appreciate that in the embodiments of the present application, Figure 2 The 3.3V power lines include two, but the two wires are both derived from the same power supply, that is, the power supply provides two 3.3V wires and the level output of the power supply wire of the MCU, and this application will not go into details about this.

[0052] Specifically, in the present application, the isolation module includes a first isolation unit and a second isolation unit, each of the isolation units is coupled to the power supply, and based on the high level generated by the power supply, conducts a signal input channel from the communication signal input end to the corresponding communication signal terminal.

[0053] For example, in this application, please continue to combine Figure 2 As shown, the isolation module includes a first isolation unit and a second isolation unit. The first isolation unit includes a first switch element Q4 and a first diode element D3. The second isolation unit includes a second switch element Q5 and a second diode element D4.

[0054] like Figure 2 As shown, the control terminal ( Figure 2 Pin 2 of Q4 in the middle) and the input terminal ( Figure 2 Pin 1 of Q4 in the Figure 2 The output terminal ( Figure 2 The pin 3 of Q4 in the middle is coupled to the corresponding communication signal input terminal (SDA input terminal), and the input terminal ( Figure 2 Pin 1 of D3 in FIG. 1 is coupled to the input terminal ( Figure 2 Pin 1 of Q4 in the middle), and the corresponding communication signal terminal ( Figure 2 The SDA terminal of the MCU, that is, the 5th pin of the MCU) is coupled, and its output terminal ( Figure 2 pin 2 of D3) and the output terminal ( Figure 2 3 pin of Q4 in the circuit).

[0055] exist Figure 2 In the embodiment, the control terminal ( Figure 2 Pin 2 of Q5 in the middle) and the input terminal ( Figure 2 Pin 1 of Q5 in the circuit) is coupled to the first node (node ​​M1), and its output terminal ( Figure 2 The pin 3 of Q5 in the middle is coupled to the corresponding communication signal input terminal (SCL input terminal), and the input terminal ( Figure 2 The first node (node ​​M1) is coupled to the first node, and the output terminal ( Figure 2 The pin 2 of D4 in the figure is coupled to the output terminal ( Figure 2 Pin 3 of Q5 in the circuit).

[0056] It can be understood that in the present application, the two power supply ends are two terminals on the same power supply. Those skilled in the art understand that in the entire I2C communication signal transmission process, each communication isolation circuit corresponds to a power supply, and the server power supply often involves multiple power supply modules in parallel. In the present application, each communication isolation circuit corresponds to a power supply module.

[0057] During specific use, when both communication signals are at a low level, that is, both the SDA signal and the SCL signal are input at a low level, the control ends of the first switch element Q4 and the second switch element Q5 are driven by 3.3V, and then the first switch element Q4 and the second switch element Q5 are turned on. At this time, the voltages at the SDA terminal and the SCL terminal of the communication processor MCU are higher than the SDA line input end and the SCL line input end. Since the first switch element Q4 is turned on, the SDA signal input end can pull down the SDA terminal of the MCU. Similarly, since the second switch element Q4 is turned on, the SCL signal input end can pull down the SCL terminal of the MCU, thereby achieving consistency in the signal levels of the MCU and the external I2C line.

[0058] When the SDA input signal and the SCL input signal are set to a high level or a floating level, since 3.3V turns on the first switch element Q4 and the second switch element Q5, and since 3.3V is higher than the voltage of the SDA and SCL input signals and due to the unidirectional conduction of D3 and D4, the SDA and SCL input signal terminals cannot pull up the SDA terminal No. 5 and the SCL terminal No. 6 of the MCU through D3 and D4. At this time, the 3.3V voltage can be sent to the SDA input signal terminal and the SCL input signal terminal through the first switch element Q4 and the second switch element Q5.

[0059] Furthermore, Figure 2D3 and D4 in the circuit can further reduce the voltage drop when 3.3V is exported to the SDA input signal end and the SCL input signal end. Specifically, 3.3V passes through the first switch element Q4 and the second switch element Q5. Since the voltage drop inside the conventional triode is about 0.5V, only 2.8V voltage can be exported after passing through the first switch element Q4 and the second switch element Q5, which cannot meet the communication level of 3.0V. In the present application, through the above circuit setting, the first switch element Q4 and the first diode element D3 are connected in parallel, and the forward voltage drop of D3 is only 0.1V. Therefore, the SDA input signal and the SCL input signal can send a voltage as high as 3.2V, which meets the communication level requirement of 3.0V and effectively ensures the reliability of communication.

[0060] When the power supply 3.3V of the present application fails (i.e., no voltage is generated), the 3.3V power line in the figure outputs a 0V level. At this time, the first switch element Q4 and the second switch element Q5 are driven at a low level and disconnected, but the first diode element D3 and the second diode element D4 are in a unidirectional conduction state. At this time, the SDA signal and the SCL signal generated by the MCU can be sent to the SDA input signal terminal and the SCL input signal terminal through D3 and D4. At the same time, the external high level cannot be transmitted to the inside of the MCU through the SDA input signal terminal and the SCL input signal terminal, so that the damage to the power supply will not affect the normal operation of the signal levels of the communication buses SDA and SCL, thereby ensuring that other power supplies can still meet the normal communication, reading and control requirements.

[0061] Those skilled in the art will appreciate that the first switch element and the second switch element of the present application may be NMOS or PMOS. Specifically, Figure 2 The switch elements in the circuit are all NMOS tubes; however, a PMOS and an inverter can be used in combination to replace the function of the NMOS tube, and this application does not impose any restrictions.

[0062] Those skilled in the art will appreciate that, for the above embodiments, the isolation module may be defined as a parallel combination of the above-mentioned switching element and a diode. In other embodiments of the present application, the isolation module may also be other equivalent circuits, which will not be described in detail herein.

[0063] In addition, in an optional embodiment, a second node is provided between the power supply terminal coupled to the power supply terminal and the power supply terminal, and the communication processor further includes a plurality of grounding terminals, each of which is coupled to a ground terminal and is coupled to the second node. The communication isolation circuit of the present application also includes: a capacitor C2, one end of which is coupled to the ground terminal and the other end is coupled to the second node M2.

[0064] In this embodiment, if Figure 2As shown, capacitor C2 plays a filtering role. In the present application, the capacitor may be 1uF / 25V. Of course, the capacitor parameter is only used as an example. The present application does not limit the capacitor parameter as long as the requirements are met.

[0065] In an optional embodiment, the first diode element and / or the second diode element is a Schottky diode element. In this embodiment, the Schottky diode elements D3 and D4 are mainly used to compensate for the large voltage difference (0.5V) of the diode elements in the switch MOS body, which causes the signal voltage of SDA and SCL to be only about 2.8V when the SDA and SCL are at high level, which may cause poor communication, and the forward voltage drop of the Schottky diode elements D3 and D4 at a small current (about 1mA) is only 0.1V, so the high-level signals of SDA and SCL can reach a voltage of more than 3.2V, meeting the requirement of the communication level of 3.0V, and effectively ensuring the reliability of communication.

[0066] In an optional embodiment, the device further includes: a first resistor R15 coupled between the first switch element Q4 and the corresponding power supply terminal 3.3V.

[0067] In an optional embodiment, the device further includes: a second resistor R16 coupled between the first switch element Q4 and the corresponding communication signal input terminal SDA.

[0068] In an optional embodiment, the device further includes: a third resistor R18 coupled between the first node M1 and the power supply terminal Vcc.

[0069] In an optional embodiment, the present invention further includes: a fourth resistor R17 coupled between the second switch element Q5 and the corresponding communication signal input terminal SCL.

[0070] In some embodiments, Figure 2 The models of D3 and D4 are SD 103AX, the models of Q4 and Q5 are 2N 7002DW, R15=10KΩ, R16=22Ω, R16=22Ω, R17=22Ω, R18=10KΩ, and the parameter of C2 is 1uF / 25V. Of course, the present invention is not limited to this. Figure 2 is just an example, further, Figure 1 and Figure 2 Terminals 1-4 and 7 of the MCU have nothing to do with the core concept of this application, and this application will not elaborate on this.

[0071] In the present application, the first to fourth resistors have a circuit current limiting function, which can protect the circuit from excessive circuit current.

[0072] It can be seen from the above technical solution that in the communication isolation circuit of the present application, when a problem occurs in the internal 3.3V of a single power module (such as no voltage), the DS poles of the switch MOS Q4 and Q5 used for isolation processing are always disconnected, and internal damage will not affect the normal operation of the signal level of the communication bus SDA and SCL, ensuring that other power supplies can still communicate and read and control normally. The present application adopts a simple and low-cost solution to effectively achieve the purpose of I2C communication line isolation processing, improve the reliability of redundant switching power supply communication control, avoid the high failure rate problem of traditional solutions, and meet the increasingly high reliability requirements of the switching power supply industry.

[0073] Furthermore, the present application also provides an I2C bus communication isolation device, including the isolation circuit as described above. Specifically, the isolation device also includes a housing in which the isolation circuit is disposed, or the isolation device also includes a carrier platform, and the isolation circuit can be exposed to the outside. The present application is not limited to this.

[0074] It can be understood that the isolation device of the present application, because its isolation circuit is provided with an isolation module, disconnects the signal input from each communication signal input end to the corresponding communication signal terminal when the power supply fails, thereby solving the problem of reduced reliability of the redundant power supply due to the non-isolation processing of the traditional I2C communication signal, and simply and quickly realizes the mutual isolation and independent operation of the power modules on the I2C communication line, avoiding the communication failure of other power modules due to the communication problem of a single power supply, thereby improving the reliability of the entire redundant work.

[0075] In the description of this specification, the description with reference to the terms "one embodiment", "a specific embodiment", "some embodiments", "for example", "example", "specific example", or "some examples" 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 application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0076] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the scope of protection of the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A communication isolation circuit, characterized in that: Each communication isolation circuit corresponds to a power module, and the communication isolation circuit includes: A communication processor, comprising two communication signal terminals and a power supply terminal; Two communication signal input terminals are independently coupled to a communication signal terminal and are used to input a communication signal; A power supply, respectively coupled to the two communication signal input terminals, the corresponding communication signal terminals and the power supply terminal; and An isolation module, used for disconnecting the signal input from each communication signal input end to the corresponding communication signal terminal when the power supply fails, so as to isolate the power modules on the communication line from each other; The isolation module comprises a first isolation unit and a second isolation unit; each of the isolation units is coupled to the power supply, and switches on a signal input channel from the communication signal input end to the corresponding communication signal terminal based on a high level generated by the power supply; The first isolation unit includes a first switch element and a first diode element, and the second isolation unit includes a second switch element and a second diode element; The control end and input end of the first switch element are coupled to the power supply, and the output end thereof is coupled to the corresponding communication signal input end; the input end of the first diode element is coupled to the input end of the first switch element and to the corresponding communication signal terminal, and the output end thereof is coupled to the output end of the first switch element; The control terminal and input terminal of the second switch element are coupled to a first node, and the output terminal thereof is coupled to the corresponding communication signal input terminal. The input terminal of the second diode element is coupled to the first node, and the output terminal thereof is coupled to the output terminal of the second switch element; wherein, When both of the communication signal input terminals are at a low level, the first switch element and the second switch element are turned on. At this time, the voltages at the two communication signal terminals of the communication processor are respectively higher than the voltages at the two communication signal input terminals. One of the communication signal input terminals pulls down the level of the corresponding communication signal terminal of the communication processor. Similarly, the other communication signal input terminal pulls down the level of the corresponding communication signal terminal of the communication processor, so that the signal level of the communication processor is consistent with that of the external I2C line. When the two communication signal input terminals are set to a high level or a floating level, the first switch element and the second switch element are turned on, the first diode element and the second diode element are unidirectionally turned on, and the voltage provided by the power supply is sent to one of the communication signal input terminals through the first switch element and the first diode element, and the voltage provided by the power supply is sent to the other communication signal input terminal through the second switch element and the second diode element, so that the voltages sent by the two communication signal input terminals respectively meet the requirements of the communication level; When the power supply fails, the first switch element and the second switch element are driven at a low level and disconnected, the first diode element and the second diode element are in a unidirectional conduction state, and the two communication signals generated by the communication processor are respectively sent to the two communication signal input terminals through the first diode element and the second diode element. At the same time, the external high level cannot be transmitted to the inside of the communication processor through the two communication signal input terminals.

2. The communication isolation circuit according to claim 1, characterized in that: The communication processor further includes a plurality of grounding terminals, each of which is coupled to a ground terminal and is coupled to a second node; the communication isolation circuit also includes: A capacitor has one end coupled to the ground terminal and the other end coupled to the second node.

3. The communication isolation circuit according to claim 1, characterized in that: The first diode element and / or the second diode element is a Schottky diode element.

4. The communication isolation circuit according to claim 1, characterized in that: Also includes: The first resistor is coupled between the first switch element and a corresponding power supply terminal.

5. The communication isolation circuit according to claim 1, characterized in that: Also includes: The second resistor is coupled between the first switch element and the corresponding communication signal input terminal.

6. The communication isolation circuit according to claim 1, characterized in that: Also includes: The third resistor is coupled between the first node and the power supply terminal.

7. The communication isolation circuit according to claim 1, characterized in that: Also includes: The fourth resistor is coupled between the second switch element and the corresponding communication signal input terminal.

8. The communication isolation circuit according to claim 1, characterized in that: The communication isolation circuit is used for an I2C bus, the communication signal includes a data signal of the I2C bus and a clock signal of the I2C bus, and correspondingly, the communication signal terminal includes a data signal terminal and a clock signal terminal.

9. A communication isolation device, characterized in that: Comprising the communication isolation circuit as described in any one of claims 1-8.

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