KVM extender automatic identification circuit and method

Abstract

This application relates to an automatic identification circuit and method for a KVM extender. The automatic identification circuit includes a level detection module, a control module, a switch management module, and an RJ45 interface module. The signal input terminal of the level detection module is connected to the signal output terminal of the RJ45 interface module. The power output terminal of the switch management module is connected to the power input terminal of the RJ45 interface module. The signal input terminal of the control module is connected to the amplitude detection signal output terminal of the level detection module, the signal output terminal of the control module is connected to the first enable signal input terminal of the switch management module, and the short-circuit detection signal output terminal of the level detection module is connected to the second enable signal input terminal of the switch management module. When the link is detected to be established through a switch, the power supply path is automatically shut off, realizing adaptive switching of power supply status under different connection scenarios, so that communication continuity and equipment security can be guaranteed simultaneously.

Description

Technical Field

[0001] This invention relates to the technical field of automatic identification of KVM extenders, and in particular to an automatic identification circuit and method for KVM extenders. Background Technology

[0002] Currently, KVM extenders have been widely used in data center server rooms in recent years to achieve remote control of servers with human-machine separation. Typically, the transmitting end of the KVM extender connects to a PC host or server via an HDMI or USB interface, and connects to the receiving end via an RJ45 interface using a CAT5E / CAT6 / CAT7 network cable. The receiving end then connects to a monitor via an HDMI interface and a keyboard and mouse via a USB interface, thus enabling remote control. Alternatively, there are applications where the transmitting end connects to a switch via a network cable, and the receiving end connects to the switch via a network cable to establish a communication link.

[0003] In existing technology, when the sending end and the receiving end are directly connected via a network cable, if the control terminal where the receiving end is located is powered off when the personnel are away from their posts or off-duty, the signal transmission between the receiving end and the sending end will be interrupted. The sending end cannot receive connection information from the receiving end, and the receiving end cannot send connection commands back to the sending end. When the receiving end is powered off for a long time, such as more than 24 hours, and is powered on again, the sending end may not resend the connection command because it has not received the feedback information for a long time, resulting in no video display and failure of keyboard and mouse functions. Summary of the Invention

[0004] To address the issue of no video display and keyboard / mouse malfunction caused by prolonged power outages in KVM extenders, this application provides an automatic identification circuit and method for KVM extenders.

[0005] An automatic identification circuit for a KVM extender is disposed between the transmitting end of the KVM extender and the receiving end of a monitor and keyboard / mouse combo application. The automatic identification circuit for a KVM extender includes a level detection module, a control module, a switch management module, and an RJ45 interface module connected to the transmitting end at one end. The other end of the RJ45 interface module is connected to another RJ45 interface module located on the receiving end; The signal input terminal of the level detection module is connected to the signal output terminal of the RJ45 interface module to obtain the level amplitude information of each pair of wires in the RJ45 interface; The power input terminal of the switch management module is connected to the VCC power supply, and the power output terminal of the switch management module is connected to the power input terminal of the RJ45 interface module to output POC power for power supply. The signal input terminal of the control module is connected to the amplitude detection signal output terminal of the level detection module, the signal output terminal of the control module is connected to the first enable signal input terminal of the switch management module, and the short circuit detection signal output terminal of the level detection module is connected to the second enable signal input terminal of the switch management module. The control module determines whether the current connection mode of the RJ45 interface is a connection established through a switch or a direct connection between the transmitter and receiver based on the comparison result of the level amplitude information and the preset amplitude threshold, and generates the corresponding first enable signal based on the determination result. The level detection module generates a judgment result based on the level amplitude information to determine whether a short circuit to ground has occurred, and then generates a corresponding second enable signal; The switch management module determines whether to turn on the power supply based on the first enable signal and the second enable signal, so as to adaptively supply power to the receiving end.

[0006] By adopting the above technical solution and setting up the collaborative relationship between the level detection module, control module, and switch management module, the current link connection mode can be determined based on the level amplitude information of each pair of wires in the RJ45 interface. When it is identified as a direct connection between the transmitting end and the receiving end, the power supply is adaptively output, and when it is identified as a connection through a switch, the power supply is turned off. This ensures communication continuity while avoiding adverse effects on the switch, and improves the overall system's adaptability and security.

[0007] Preferably, the switch management module includes a MOSFET Q10 and a switch conduction unit. The first conduction terminal of the MOSFET Q10 is connected to the VCC power supply, the second conduction terminal of the MOSFET Q10 is connected to the power input terminal of the RJ45 interface module, and the controlled terminal of the MOSFET Q10 is connected to the control signal output terminal of the switch conduction unit. The switch conduction unit is used to receive a first enable signal and a second enable signal to output corresponding control signals to the MOSFET Q10.

[0008] By adopting the above technical solution, by placing the MOSFET Q10 between the VCC power supply and the power input terminal of the RJ45 interface module, and controlling it with a control signal output by the switching unit, the switching of the POC power supply can be stably switched at the hardware level, thereby improving the reliability and response speed of the power supply path, and enhancing the stability of power supply control.

[0009] Preferably, at least one pull-up resistor is connected between the second conducting terminal of MOSFET Q10 and the VCC power supply. The pull-up resistor and the second conducting terminal of MOSFET Q10 form a weak pull-up power supply node connected to the power input terminal of the RJ45 interface module. The node voltage of the weak pull-up power supply node is less than the power supply voltage required by the receiving end.

[0010] By adopting the above technical solution, a weak pull-up power supply node is formed by setting a pull-up resistor at the second conducting terminal of the MOSFET Q10. This node still has a detectable voltage level when the MOSFET is not conducting. However, due to the current limitation, it cannot drive the receiver to work. Thus, the level detection function is realized without outputting effective power supply, thereby improving the security and accuracy of link status identification.

[0011] Preferably, the switching unit includes MOSFET HQ17 and MOSFET HQ18. The first conducting terminal of MOSFET HQ18 is connected to the 3.3V power supply, the second conducting terminal of MOSFET HQ18 is grounded, the controlled terminal of MOSFET HQ18 is connected to the signal output terminal of the control module, the first conducting terminal of MOSFET HQ17 is connected to the controlled terminal of MOSFET Q10, the second conducting terminal of MOSFET HQ17 is grounded, the first conducting terminal of MOSFET HQ18 and the 3.3V power supply form a corresponding first signal node, and the controlled terminal of MOSFET HQ17 is connected to the first signal node.

[0012] By adopting the above technical solution, using MOSFETs HQ17 and HQ18 to form a switch conduction unit, and realizing signal transmission through the first signal node, the first enable signal output by the control module can be transmitted to the controlled terminal of MOSFET Q10 through this structure, thereby achieving stable control of the main power supply path and improving the reliability and anti-interference capability of switch control.

[0013] Preferably, the RJ45 interface module includes an interface body chip HCON2 and an interface coupling chip HU69. The interface body chip HCON2 and the interface coupling chip HU69 are connected by four sets of pairs of wires. The interface coupling chip HU69 is provided with a level detection port for detecting the level amplitude information of the four sets of pairs of wires. The level detection port is connected to the signal input terminal of the level detection module.

[0014] By adopting the above technical solution, the interface body chip HCON2 and the interface coupling chip HU69 are connected through four sets of wires, and a level detection port is set on the interface coupling chip, so that the level amplitude information can be directly obtained from the corresponding wire pair of the RJ45 interface, thereby providing accurate detection data for the level detection module and improving the accuracy of link identification.

[0015] Preferably, the level detection module includes a detection unit and a ground short circuit judgment unit. The first conducting terminal of each detection unit is connected to the level detection port, and the second conducting terminal of each detection unit is grounded. Two pairs of wires are identified as target detection pairs, and the detection unit corresponding to the target detection pairs is identified as the target unit. A second signal node is provided between the target unit and the level detection port. The second signal node is connected to the signal input terminal of the ground short circuit judgment unit, and the signal output terminal of the ground short circuit judgment unit is connected to the second enable signal input terminal of the switch management module.

[0016] By adopting the above technical solution, by setting up a detection unit and a ground short circuit judgment unit, and forming a second signal node between the detection unit and the level detection port corresponding to the target detection pair, the level status of the target detection pair can be centrally detected, and the existence of a ground short circuit can be further determined, thereby improving the accuracy and reliability of abnormal status identification.

[0017] Preferably, the short-circuit to ground detection unit includes MOSFET HQ20 and MOSFET HQ19. The first conducting terminal of MOSFET HQ20 is connected to the 3.3V power supply, the second conducting terminal of MOSFET HQ20 is grounded, the controlled terminal of MOSFET HQ20 is connected to the second signal node, the first conducting terminal of MOSFET HQ19 is connected to the output of the second enable signal, the second conducting terminal of MOSFET HQ19 is grounded, a corresponding third signal node is formed between the first conducting terminal of MOSFET HQ20 and the 3.3V power supply, the controlled terminal of MOSFET HQ19 is connected to the third signal node, and the third signal node is connected to the first signal node, so as to output the second enable signal to the switch conduction unit.

[0018] By adopting the above technical solution, and by using MOSFETs HQ20 and HQ19 to form a ground short circuit judgment unit, and connecting it to the first signal node through a third signal node, the ground short circuit judgment result can directly participate in the control process of the switch conduction unit, thereby realizing the rapid suppression of abnormal states on the power supply path and improving the protection capability of the system.

[0019] Preferably, the detection unit includes at least one first detection resistor and at least one stabilizing capacitor. The first end of the first detection resistor is connected to the level detection port, the second end of the first detection resistor is connected to the first end of the stabilizing capacitor, and the second end of the stabilizing capacitor is grounded.

[0020] By adopting the above technical solution, and by setting a circuit structure formed by a first detection resistor and a stabilizing capacitor in the detection unit, the level detection signal is stabilized during transmission, thereby reducing the impact of signal fluctuations on the detection results and improving the stability and accuracy of level amplitude detection.

[0021] Preferably, the second signal node is connected to the signal input terminal of the short-circuit to ground detection unit through a second detection resistor.

[0022] By adopting the above technical solution, and by setting a second detection resistor between the second signal node and the ground short circuit judgment unit, the detection signal is further regulated and isolated during transmission, thereby improving the reliability of ground short circuit judgment and avoiding misjudgment.

[0023] An automatic identification method for KVM extenders is applied to an automatic identification circuit for KVM extenders. The automatic identification method for KVM extenders includes: Obtain the voltage amplitude information of the target detection line in the RJ45 interface module, and compare the voltage amplitude information with the preset amplitude threshold to generate the corresponding comparison result; Obtain the link status indicator light information of the RJ45 interface module, and generate the corresponding first enable signal based on the link status indicator light information and the comparison result; Based on the level amplitude information, a judgment result is generated to determine whether a short circuit to ground has occurred. When all judgment results are normal results that indicate that no short circuit to ground has occurred, a conduction enable signal is generated; otherwise, a disconnect enable signal is generated. The second enable signal includes the conduction enable signal and the disconnect enable signal. Based on the first enable signal and the second enable signal, the control switch management module executes the corresponding switching action.

[0024] By adopting the above technical solution, the system obtains the level amplitude information and link status indicator information, and generates the first enable signal and the second enable signal by combining the ground short circuit judgment result. This enables the switch management module to execute the corresponding switch action, allowing the system to adaptively adjust the power supply status according to the link status and abnormal conditions, thereby achieving intelligent adaptation and safety control for different connection scenarios.

[0025] In summary, this application includes at least one of the following beneficial technical effects: This application addresses the aforementioned issues by establishing a collaborative mechanism for link identification and power supply control based on the electrical characteristics of the RJ45 interface between the transmitting and receiving ends. Its core lies in introducing a level detection module in conjunction with a control module to acquire the voltage levels of each pair of wires on the RJ45 interface in real time and compare them with preset amplitude thresholds. This allows for direct physical-layer determination of whether the current link is a direct connection between the transmitting and receiving ends or established via a switch, without relying on communication protocols. Simultaneously, the level detection module further analyzes voltage level changes along the same electrical path to determine if there is a short circuit to ground. This determination, along with the link identification result, is converted into a first enable signal and a second enable signal, respectively, and input to the switch management module. The switch management module, under the combined effect of these two enable conditions, decides whether to activate the power supply path, thus coupling power supply control with link identification and anomaly detection. When the transmitter and receiver are directly connected, the POC power supply path can be automatically activated. Even if the control terminal where the receiver is located loses power, the communication between the transmitter and receiver can be maintained, avoiding problems such as no video or keyboard / mouse failure due to loss of connection caused by prolonged power outages. When the link is detected to be established through a switch, the power supply path is automatically shut off, thereby avoiding adverse effects caused by power output to the switch side. At the same time, a short-circuit detection mechanism to ground further improves power supply safety and prevents false connection under abnormal conditions. Overall, it realizes adaptive switching of power supply status under different connection scenarios, ensuring both communication continuity and device security. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating a direct connection between the transmitting and receiving ends in an automatic identification circuit for a KVM extender according to an embodiment of this application. Figure 2 This is a flowchart illustrating the connection establishment method via a switch in an automatic identification circuit for a KVM extender according to one embodiment of this application. Figure 3 This is a partial circuit diagram of the switch management module in an automatic identification circuit for a KVM extender according to one embodiment of this application; Figure 4 This is a partial circuit diagram of the level detection module and the RJ45 interface module in an automatic identification circuit for a KVM extender according to one embodiment of this application; Figure 5 This is a partial circuit diagram of a short-circuit-to-ground judgment unit in an automatic identification circuit for a KVM extender according to one embodiment of this application; Figure 6 This is a partial circuit diagram of the switch in an automatic identification circuit for a KVM extender according to one embodiment of this application; Figure 7This is a flowchart illustrating the implementation of an automatic KVM extender identification method in one embodiment of this application. Detailed Implementation

[0027] The present application will be further described in detail below with reference to the accompanying drawings.

[0028] In one embodiment, such as Figure 1 , Figure 2 and Figure 6 As shown, this application discloses an automatic identification circuit for a KVM extender, which is located between the transmitting end of the KVM extender and the receiving end of the monitor keyboard and mouse group application. The automatic identification circuit for a KVM extender includes a level detection module, a control module, a switch management module, and an RJ45 interface module connected to the transmitting end at one end. The other end of the RJ45 interface module is connected to another RJ45 interface module located on the receiving end; The signal input terminal of the level detection module is connected to the signal output terminal of the RJ45 interface module to obtain the level amplitude information of each pair of wires in the RJ45 interface; The power input terminal of the switch management module is connected to the VCC power supply, and the power output terminal of the switch management module is connected to the power input terminal of the RJ45 interface module to output POC power for power supply. The signal input terminal of the control module is connected to the amplitude detection signal output terminal of the level detection module, the signal output terminal of the control module is connected to the first enable signal input terminal of the switch management module, and the short circuit detection signal output terminal of the level detection module is connected to the second enable signal input terminal of the switch management module. The control module determines whether the current connection mode of the RJ45 interface is a connection established through a switch or a direct connection between the transmitter and receiver based on the comparison result of the level amplitude information and the preset amplitude threshold. The level detection module generates a judgment result based on the level amplitude information to determine whether a short circuit to ground has occurred, and then generates a corresponding second enable signal; The switch management module determines whether to turn on the power supply based on the first enable signal and the second enable signal, so as to adaptively supply power to the receiving end.

[0029] In this embodiment, an automatic identification circuit for a KVM extender is applied between the transmitter and receiver of the KVM extender. The transmitter is used to receive HDMI signal input, USB 2.0 signal, bidirectional audio signal and serial port signal, and establishes a communication link with the receiver through an RJ45 interface module. The level detection module, control module and switch management module work together to realize automatic identification of the link connection mode and adaptive control of the POC power supply.

[0030] In the specific implementation process, after the KVM extender transmitter is powered on, the control module begins to collect the voltage level information of each pair of wires in the 8 network cables of the RJ45 interface module through the level detection module, and compares the collected voltage level information with the preset voltage level threshold. When the comparison result shows that the voltage level of each pair of wires is consistent with the default value, it is determined that the current transmitter and receiver are directly connected. At this time, the control module generates the corresponding first enable signal, and together with the second enable signal generated by the level detection module, controls the switch management module to turn on, so that the switch management module outputs VCC power as POC power, and provides 12V voltage to the receiver through the RJ45 interface module. In this way, even if there is a power failure at the remote control end where the receiver is located, such as when the operator leaves work or leaves the work site for a long time and needs to turn off the power of all equipment, the communication between the transmitter and receiver can still be maintained. This avoids the problem of no video or keyboard and mouse function failure due to the receiver being powered off for a long time, such as more than 24 hours, and then being unable to re-establish the connection after being powered on.

[0031] When the level detection module detects that the level amplitude information of each pair of wires in the RJ45 interface module is inconsistent with the default value, it determines that the current link is a connection established through the switch. At this time, the control module does not generate the first enable signal to enable the switch management module to conduct, and the switch management module remains in the off state, disconnecting the POC power output path and thus avoiding power output to the switch side. In this state, the transmitting end and the receiving end form a new communication link through the switch to ensure the normal operation of the system.

[0032] Furthermore, when the transmitting and receiving ends are directly connected via an RJ45 interface module, video signals, serial port signals, USB 2.0 device signals, and keyboard and mouse signals are all transmitted through the eight network cables of the RJ45 interface module. At the same time, when the switch management module is in the ON state, it outputs 12V power to the receiving end through the corresponding wire pairs of the RJ45 interface module. The MOSFET in the switch management module is turned on or off under the control signal output by the control module to realize the power supply of POC on or off.

[0033] During basic operation, when the KVM extender is powered on, the control pins of the control module are at a high level by default. When the transmitter is directly connected to the receiver via a CAT6 network cable and a connection is established, the LINK status signal of the RJ45 interface module becomes valid. By detecting this LINK status signal and comprehensively judging the amplitude information of each pair of lines of the RJ45 interface module, the control switch management module is turned on, thereby outputting POC power. When the transmitter is connected to the switch via a CAT6 network cable, the level state corresponding to specific pins of the RJ45 interface module changes. For example, the level detection nodes corresponding to pins 4 and 7 are at a low level, corresponding to the electrical characteristics of pins 4 and 5, and pins 7 and 8 in the switch interface circuit. At this time, the control module determines that it is a switch connection mode and controls the switch management module to remain in the off state, keeping the POC power supply off by default, thereby avoiding any impact on the switch.

[0034] It realizes automatic identification of link connection mode based on specific pin level states of RJ45 interface module, and controls POC power supply based on this, so that the system can maintain communication when the transmitting end and receiving end are directly connected, and ensure device safety when connected through switch, thus taking into account both communication maintenance and security on the switch side in the event of remote power failure.

[0035] like Figure 3 As shown, the switch management module further includes a MOSFET Q10 and a switch conduction unit. The first conduction terminal of the MOSFET Q10 is connected to the VCC power supply, the second conduction terminal of the MOSFET Q10 is connected to the power input terminal of the RJ45 interface module, and the controlled terminal of the MOSFET Q10 is connected to the control signal output terminal of the switch conduction unit. The switch conduction unit is used to receive the first enable signal and the second enable signal to output the corresponding control signal to the MOSFET Q10.

[0036] Furthermore, at least one pull-up resistor is connected between the second conducting terminal of MOSFET Q10 and the VCC power supply. The pull-up resistor and the second conducting terminal of MOSFET Q10 form a weak pull-up power supply node connected to the power input terminal of the RJ45 interface module. The node voltage of the weak pull-up power supply node is less than the power supply voltage required by the receiving end.

[0037] Furthermore, the switching unit includes MOSFET HQ17 and MOSFET HQ18. The first conducting terminal of MOSFET HQ18 is connected to the 3.3V power supply, the second conducting terminal of MOSFET HQ18 is grounded, the controlled terminal of MOSFET HQ18 is connected to the signal output terminal of the control module, the first conducting terminal of MOSFET HQ17 is connected to the controlled terminal of MOSFET Q10, the second conducting terminal of MOSFET HQ17 is grounded, the first conducting terminal of MOSFET HQ18 and the 3.3V power supply form a corresponding first signal node, and the controlled terminal of MOSFET HQ17 is connected to the first signal node.

[0038] In this embodiment, the switch management module includes a MOSFET Q10 and a switch conduction unit composed of MOSFETs HQ17 and HQ18. The first conduction terminal of MOSFET Q10 is connected to the VCC power supply, and its second conduction terminal is connected to the power input terminal of the RJ45 interface module. It is used to output the VCC power supply as POC power supply and supply it to the receiving end when in the conduction state. The controlled terminal of MOSFET Q10 is connected to the control signal output terminal of the switch conduction unit, so that the switch conduction unit controls its conduction or cutoff state.

[0039] Specifically, the switching unit includes MOSFET HQ18 and MOSFET HQ17. The first conducting terminal of MOSFET HQ18 is connected to a 3.3V power supply, and its second conducting terminal is grounded. The controlled terminal of MOSFET HQ18 is connected to the signal output terminal of the control module to receive a first enable signal. A corresponding first signal node is formed between the first conducting terminal of MOSFET HQ18 and the 3.3V power supply. The first signal node is connected to the controlled terminal of MOSFET HQ17 as a control signal transmission node, thereby transmitting the first enable signal to MOSFET HQ17.

[0040] The first conducting terminal of MOSFET HQ17 is connected to the controlled terminal of MOSFET Q10, and its second conducting terminal is grounded. The level state of the controlled terminal of MOSFET Q10 is controlled by the conduction or cutoff of MOSFET HQ17. When the level corresponding to the first signal node changes, MOSFET HQ17 is turned on or off according to the level of its controlled terminal, thereby changing the potential of the controlled terminal of MOSFET Q10, so that MOSFET Q10 switches between the on state and the off state, thereby realizing the control of the POC power output path.

[0041] Furthermore, a pull-up resistor is provided between the second conducting terminal of MOSFET Q10 and the VCC power supply. This forms a weak pull-up power supply node at the second conducting terminal of MOSFET Q10 when it is not conducting, so that the power input terminal of the RJ45 interface module is in a detection state with a certain voltage. However, since the current corresponding to the pull-up resistor is limited, it cannot drive the receiver to work, thereby realizing the function of detecting the output level.

[0042] Specifically, the purpose of setting a weak pull-up power supply node in this embodiment is to provide a perceptible level reference environment for the power input terminal of the RJ45 interface module when the switch management module is not turned on, so that the level detection module can obtain the electrical status information of the line without outputting effective power supply. Specifically, by introducing a high-resistance pull-up path between the second conducting terminal of MOSFET Q10 and the VCC power supply, the node presents a voltage level close to the power supply potential under no-load or normal conditions. When the target detection line is connected to the switch or there is an abnormal conduction to ground, the potential of the node will change significantly, thus providing a distinguishable detection basis for the level detection module. At the same time, since the current corresponding to the pull-up path is limited and cannot meet the operating current requirements of the receiving end, it will not form an actual power supply to the receiving end when the switch management module is not turned on, thereby avoiding equipment risks caused by erroneous power supply. Through this structural design, it is possible to pre-detect the link connection mode and abnormal state even when the power supply path is closed, so that the detection process and the actual power supply process are independent of each other, thereby improving the safety and reliability of the overall system while ensuring detection accuracy.

[0043] In addition, a resistor R1340 is placed between the controlled terminal of MOSFET Q10 and the VCC power supply, forming a stable network for the control node along with a capacitor to ensure the potential stability of MOSFET Q10 during switching. A diode D100 is also placed at the control node to limit the control node voltage, preventing abnormal voltage from affecting MOSFET Q10. The controlled terminal of MOSFET HQ17 is connected to its first conducting terminal via a resistor R1341 and grounded via a resistor R1338, thus forming a stable structure for the controlled terminal level of MOSFET HQ17. The controlled terminal of MOSFET HQ18 is connected to the signal output terminal of the control module via a resistor R1344 and grounded via a resistor R1345 to ensure its controlled terminal level remains stable when there is no input signal. It is also connected to the 3.3V power supply via a resistor R1342 to form a stable potential base at the first signal node.

[0044] Furthermore, such as Figure 4 As shown, the RJ45 interface module includes an interface body chip HCON2 and an interface coupling chip HU69. The interface body chip HCON2 and the interface coupling chip HU69 are connected by four sets of pairs of wires. The interface coupling chip HU69 is provided with a level detection port for detecting the level amplitude information of the four sets of pairs of wires. The level detection port is connected to the signal input terminal of the level detection module.

[0045] In this embodiment, the RJ45 interface module includes an interface body chip HCON2 and an interface coupling chip HU69. The interface body chip HCON2 is used to realize the physical connection with the external network cable. It has multiple pins corresponding to the RJ45 interface, and is connected to the interface coupling chip HU69 through four pairs of wires, thereby introducing the signals of each pair of wires transmitted through the RJ45 interface into the interface coupling chip HU69.

[0046] Specifically, the interface chip HCON2 and the interface coupling chip HU69 are connected one-to-one through four sets of pairs. Each set of pairs is used to transmit a differential signal, enabling the transmission of video signals, USB 2.0 signals, serial port signals, and keyboard and mouse signals between the transmitting and receiving ends through the four sets of pairs. The interface coupling chip HU69 couples the signals of the four sets of pairs and has a level detection port inside corresponding to each set of pairs. The level detection port is connected to the signal path of each of the four sets of pairs, thereby obtaining the level amplitude information of each set of pairs.

[0047] Furthermore, the level detection port on the interface coupling chip HU69 is connected to the signal input terminal of the level detection module via a wire, enabling the level detection module to directly acquire the level amplitude information from the four pairs of wires and process the level amplitude information. Through this structure, the level detection module can determine the electrical characteristics of the current link based on the level detection signal output by the interface coupling chip HU69 without additional communication parsing process, thereby providing basic data for the control module to subsequently determine the connection mode of the RJ45 interface module.

[0048] Through the above structural arrangement, the interface chip HCON2 and the interface coupling chip HU69 can not only complete the signal transmission function, but also extract and detect the amplitude information of four pairs of lines. This provides a stable and accurate detection signal for the level detection module without affecting the normal signal transmission, thereby improving the reliability and accuracy of link identification.

[0049] Furthermore, such as Figure 4 As shown, the level detection module includes a detection unit and a ground short circuit judgment unit. The first conducting terminal of each detection unit is connected to the level detection port, and the second conducting terminal of each detection unit is grounded. Two pairs of lines are identified as target detection pairs, and the detection unit corresponding to the target detection pairs is identified as the target unit. A second signal node is provided between the target unit and the level detection port. The second signal node is connected to the signal input terminal of the ground short circuit judgment unit, and the signal output terminal of the ground short circuit judgment unit is connected to the second enable signal input terminal of the switch management module.

[0050] In this embodiment, the level detection module includes a detection unit and a short-circuit to ground judgment unit. Each detection unit is respectively set to correspond to the level detection port on the interface coupling chip HU69. The first conducting terminal of each detection unit is connected to the corresponding level detection port, and its second conducting terminal is grounded, thereby forming a level lead-out and reference grounding path on the signal path corresponding to each pair of lines, so that the level detection module can obtain the level amplitude information of each pair of lines.

[0051] In the specific implementation process, two pairs of wires are selected from the four pairs of wires of the RJ45 interface module as target detection pairs, and the detection unit corresponding to the target detection pairs is determined as the target unit. A second signal node is set between the target unit and the corresponding level detection port so that the level amplitude information of the target detection pairs can be collected and led out at the second signal node. The second signal node is connected to the signal input terminal of the ground short circuit judgment unit through a wire, thereby transmitting the level state of the target detection pairs to the ground short circuit judgment unit.

[0052] The short-circuit-to-ground detection unit determines whether a short circuit to ground exists based on the level state at the second signal node, and generates a corresponding second enable signal based on the determination result. The second enable signal is output by the short-circuit-to-ground detection unit to the second enable signal input terminal of the switch management module. Through the above structural configuration, the level detection module can not only detect the level amplitude information of each pair of wires in the RJ45 interface module, but also determine the short circuit to ground based on the level state of the target detection pair of wires, thereby providing a reliable safety judgment basis for the conduction control of the switch management module.

[0053] Furthermore, such as Figure 5 As shown, the short-circuit detection unit includes MOSFET HQ20 and MOSFET HQ19. The first conducting terminal of MOSFET HQ20 is connected to the 3.3V power supply, the second conducting terminal of MOSFET HQ20 is grounded, and the controlled terminal of MOSFET HQ20 is connected to the second signal node. The first conducting terminal of MOSFET HQ19 is connected to the output of the second enable signal, and the second conducting terminal of MOSFET HQ19 is grounded. A corresponding third signal node is formed between the first conducting terminal of MOSFET HQ20 and the 3.3V power supply. The controlled terminal of MOSFET HQ19 is connected to the third signal node, and the third signal node is connected to the first signal node to output the second enable signal to the switch conducting unit.

[0054] In this embodiment, the short-circuit to ground detection unit includes MOSFET HQ20 and MOSFET HQ19. The first conducting terminal of MOSFET HQ20 is connected to a 3.3V power supply, and its second conducting terminal is grounded. The controlled terminal of MOSFET HQ20 is connected to a second signal node to receive the level status signal corresponding to the target detection line. A third signal node is formed between the first conducting terminal of MOSFET HQ20 and the 3.3V power supply, so that the level change of the second signal node can be converted into the corresponding level state of the third signal node through MOSFET HQ20.

[0055] Specifically, when the level of the second signal node changes, the MOSFET HQ20 turns on or off according to the level of its controlled terminal, causing the third signal node to exhibit a corresponding level change, thereby converting the level information of the target detection line into a control signal that can be used by the subsequent stage; the first conducting terminal of the MOSFET HQ19 is used to output the second enable signal, and its second conducting terminal is grounded. The controlled terminal of the MOSFET HQ19 is connected to the third signal node, so that the level change of the third signal node can further control the conducting or cutting off state of the MOSFET HQ19.

[0056] Furthermore, the third signal node is connected to the first signal node, so that the level state formed by the MOSFET HQ20 can be directly transmitted to the control path where the switch conduction unit is located. When the MOSFET HQ19 is turned on or off under the control of the third signal node, a second enable signal is generated and output to the switch conduction unit, thereby participating in the control of the on or off state of the MOSFET Q10.

[0057] Through the above structural relationship, the ground short circuit judgment unit can determine whether there is a ground short circuit in the target detection line based on the level state of the second signal node, and convert the judgment result into a second enable signal and output it to the switch conduction unit. This suppresses switch conduction when a ground short circuit exists and allows switch conduction when no ground short circuit occurs, thereby improving the safety and reliability of power supply control.

[0058] In this embodiment, as Figure 3 and Figure 5As shown, MOSFET HQ19 is positioned between the third signal node and ground, and forms a parallel conduction relationship with the control path of the controlled terminal of MOSFET HQ17, thereby constraining the level state of the first signal node. Specifically, even if MOSFET HQ18 is in the conducting state after receiving the first enable signal, pulling the first signal node to the corresponding level, the controlled terminal of MOSFET HQ17 still needs to rely on the potential change of this node to achieve conduction. However, when MOSFET HQ19 is in the conducting state, the third signal node forms a conduction path to ground through MOSFET HQ19, thereby pulling down the potential corresponding to the first signal node, making it impossible for the controlled terminal of MOSFET HQ17 to maintain the level condition required for conduction.

[0059] Therefore, it can be seen that MOSFET HQ19 has a higher priority suppression effect on the conduction state of MOSFET HQ17. That is, when MOSFET HQ19 is conducting, regardless of whether MOSFET HQ18 is conducting, it will clamp the control node through the ground conduction path, thereby blocking the conduction condition of MOSFET HQ17 and keeping MOSFET Q10 in the off state. Only when MOSFET HQ19 is in the off state can the level control path formed by MOSFET HQ18 effectively act on the controlled terminal of MOSFET HQ17, thereby realizing the normal conduction control of MOSFET Q10.

[0060] With the above structural configuration, the second enable signal generated by the short-circuit to ground detection unit can directly intervene in the control path through the MOSFET HQ19. When an abnormal state (such as a short circuit to ground) is detected, the conduction path is cut off first, thereby avoiding the MOSFET Q10 from being mis-turned on, and improving the safety and reliability of power supply control.

[0061] Furthermore, such as Figure 4 As shown, the detection unit includes at least one first detection resistor and at least one stabilizing capacitor. The first end of the first detection resistor is connected to the level detection port, and the second end of the first detection resistor is connected to the first end of the stabilizing capacitor. The second end of the stabilizing capacitor is grounded. The first detection resistor is... Figure 3 The resistors HR43, HR45, HR46, and HR47 are included, along with the stabilizing capacitor. Figure 3 The capacitors in the capacitors are HC149, HC150, HC151 and HC152.

[0062] Furthermore, the second signal node is connected to the signal input terminal of the short-circuit-to-ground detection unit via a second detection resistor, which is... Figure 3 The resistors HR355 and HR356 are included.

[0063] In this embodiment, the level detection module, in its actual implementation, is configured to work in conjunction with a detection unit and a short-circuit to ground judgment unit to acquire the level amplitude information of each pair of wires in the RJ45 interface module and to determine abnormal states. Specifically, each detection unit is connected to a level detection port on the interface coupling chip. The first end of the first detection resistor is connected to the level detection port, and its second end is connected to the first end of the stabilizing capacitor, forming a level output node between them. The second end of the stabilizing capacitor is grounded, thus allowing the level amplitude information from each pair of wires in the RJ45 interface module to be output via the first detection resistor and filtered and stabilized by the stabilizing capacitor to prevent signal fluctuations from affecting the level detection results. Based on this, a target is selected from each pair of wires. The system identifies a target detection line and uses its corresponding detection unit as the target unit. A second signal node is formed between the target unit and the level detection port, allowing the level state of the target detection line to be represented by the second signal node. Simultaneously, the second signal node is connected to the signal input terminal of the ground short-circuit judgment unit via a second detection resistor. This provides further electrical isolation and amplitude adjustment of the level state before it is transmitted to the ground short-circuit judgment unit, thereby improving the stability and reliability of the ground short-circuit judgment without affecting the original level detection path. Through this structural arrangement, the level detection module can effectively determine whether a ground short circuit exists on the target detection line while acquiring level amplitude information, providing a stable input basis for the subsequent generation of the second enable signal.

[0064] like Figure 7 As shown, an automatic KVM extender identification method is applied to a KVM extender automatic identification circuit. The KVM extender automatic identification method includes: S10. Obtain the level amplitude information of the target detection line in the RJ45 interface module, and compare the level amplitude information with the preset amplitude threshold to generate the corresponding comparison result. S20. Obtain the link status indicator light information of the RJ45 interface module, and generate the corresponding first enable signal based on the link status indicator light information and the comparison result. S30. Generate a judgment result for determining whether a short circuit to ground has occurred based on the level amplitude information. When all judgment results are normal results that indicate that no short circuit to ground has occurred, generate a conduction enable signal; otherwise, generate a disconnect enable signal. The second enable signal includes the conduction enable signal and the disconnect enable signal. S40. Based on the first enable signal and the second enable signal, control the switch management module to execute the corresponding switch action.

[0065] In this embodiment, an automatic KVM extender identification method is applied to an automatic KVM extender identification circuit. The RJ45 interface module is an interface structure used to establish a physical connection between the transmitting and receiving ends. Internally, it contains multiple pairs of wire channels corresponding to the network cable, used to carry video signals, USB signals, and control signals. The target detection pairs are selected from the multiple pairs of wires in the RJ45 interface module to characterize the electrical characteristics of the link. Their voltage levels reflect the current connection method and line status. The voltage amplitude information is the voltage amplitude corresponding to the target detection pairs in the current operating state, obtained by the voltage detection module through sampling of the target detection pairs and characterized as continuous or discrete voltage values. The preset amplitude threshold is a reference voltage range or judgment benchmark pre-set during system design based on the electrical characteristics of the direct connection state and the switch connection state. It is used to compare the voltage amplitude information, thereby forming a comparison result that can distinguish different connection methods. This comparison result reflects whether the current voltage level of the target detection pairs conforms to the preset direct connection characteristics or switch connection characteristics.

[0066] Furthermore, the link status indicator light information is a status indication signal generated by the RJ45 interface module during the link establishment process. It is usually output by the interface chip and corresponds to the link connection status. When the link is successfully established, the corresponding signal is in a valid state, which is used to indicate whether there is a valid physical connection between the transmitting end and the receiving end. The first enable signal is a control signal generated by the control module after making a comprehensive judgment based on the link status indicator light information and the comparison result. Its level is used to indicate whether the power supply path opening condition is met. That is, when the link is established and the comparison result indicates a direct connection, the enable state is output; otherwise, the disable state is output.

[0067] Meanwhile, the judgment result of short circuit to ground is the result of judging whether there is an abnormal ground conduction of the target detection line based on the level amplitude information. This judgment is achieved by analyzing whether the level amplitude information is abnormally reduced or pulled down to near ground potential. When all judgment results indicate that no short circuit to ground has occurred, it means that each line is in normal working condition. At this time, a conduction enable signal is generated to allow the power supply path to be opened. When any judgment result indicates that a short circuit to ground exists, a disconnect enable signal is generated to prevent the power supply path from conducting. The second enable signal is a unified expression of the conduction enable signal and the disconnect enable signal. It is used to transmit line safety status information to the switch management module.

[0068] Finally, the switch management module is a power supply control unit located between the VCC power supply and the RJ45 interface module. It includes a MOSFET and its control path structure, which are used to perform corresponding switching actions after receiving the first enable signal and the second enable signal. The switching action controls the conduction or cutoff of the power supply path. When the first enable signal indicates that power supply is allowed and the second enable signal indicates that there is no abnormality, the switch management module is turned on, so that the VCC power supply is output to the receiving end through the RJ45 interface module in the form of POC power supply. When the above conditions are not met, it remains in the cutoff state, thereby achieving link identification while ensuring power supply safety.

[0069] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. An automatic identification circuit for a KVM extender, characterized in that, The KVM extender automatic identification circuit, located between the transmitting end of the KVM extender and the receiving end of the monitor / keyboard / mouse set application, includes a level detection module, a control module, a switch management module, and an RJ45 interface module connected to the transmitting end at one end. The other end of the RJ45 interface module is connected to another RJ45 interface module located on the receiving end; The signal input terminal of the level detection module is connected to the signal output terminal of the RJ45 interface module to obtain the level amplitude information of each pair of lines in the RJ45 interface; The power input terminal of the switch management module is connected to the VCC power supply, and the power output terminal of the switch management module is connected to the power input terminal of the RJ45 interface module to output POC power for power supply. The signal input terminal of the control module is connected to the amplitude detection signal output terminal of the level detection module, the signal output terminal of the control module is connected to the first enable signal input terminal of the switch management module, and the short circuit detection signal output terminal of the level detection module is connected to the second enable signal input terminal of the switch management module. The control module determines whether the current connection mode of the RJ45 interface is a connection established through a switch or a direct connection between the transmitter and receiver based on the comparison result of the level amplitude information and the preset amplitude threshold, and generates a corresponding first enable signal based on the determination result. The level detection module generates a judgment result for determining whether a short circuit to ground has occurred based on the level amplitude information, and then generates a corresponding second enable signal; The switch management module determines whether to turn on the circuit based on the first enable signal and the second enable signal, so as to adaptively supply power to the receiving end.

2. The KVM extender automatic identification circuit according to claim 1, characterized in that, The switch management module includes a MOSFET Q10 and a switch conduction unit. The first conduction terminal of the MOSFET Q10 is connected to the VCC power supply, the second conduction terminal of the MOSFET Q10 is connected to the power input terminal of the RJ45 interface module, and the controlled terminal of the MOSFET Q10 is connected to the control signal output terminal of the switch conduction unit. The switch conduction unit is used to receive the first enable signal and the second enable signal to output the corresponding control signal to the MOSFET Q10.

3. The KVM extender automatic identification circuit according to claim 2, characterized in that, At least one pull-up resistor is connected between the second conducting terminal of the MOSFET Q10 and the VCC power supply. The pull-up resistor and the second conducting terminal of the MOSFET Q10 form a weak pull-up power supply node connected to the power input terminal of the RJ45 interface module. The node voltage of the weak pull-up power supply node is less than the power supply voltage required by the receiving end.

4. The KVM extender automatic identification circuit according to claim 2, characterized in that, The switching unit includes MOSFET HQ17 and MOSFET HQ18. The first conducting terminal of MOSFET HQ18 is connected to a 3.3V power supply, and the second conducting terminal of MOSFET HQ18 is grounded. The controlled terminal of MOSFET HQ18 is connected to the signal output terminal of the control module. The first conducting terminal of MOSFET HQ17 is connected to the controlled terminal of MOSFET Q10, and the second conducting terminal of MOSFET HQ17 is grounded. A corresponding first signal node is formed between the first conducting terminal of MOSFET HQ18 and the 3.3V power supply, and the controlled terminal of MOSFET HQ17 is connected to the first signal node.

5. The KVM extender automatic identification circuit according to claim 4, characterized in that, The RJ45 interface module includes an interface body chip HCON2 and an interface coupling chip HU69. The interface body chip HCON2 and the interface coupling chip HU69 are connected by four sets of pairs of wires. The interface coupling chip HU69 is provided with a level detection port for detecting the level amplitude information corresponding to the four sets of pairs of wires. The level detection port is connected to the signal input terminal of the level detection module.

6. The KVM extender automatic identification circuit according to claim 5, characterized in that, The level detection module includes a detection unit and a ground short circuit judgment unit. The first conducting terminal of each detection unit is connected to the level detection port, and the second conducting terminal of each detection unit is grounded. Two pairs of wires are identified as target detection pairs, and the detection unit corresponding to the target detection pairs is identified as the target unit. A second signal node is provided between the target unit and the level detection port. The second signal node is connected to the signal input terminal of the ground short circuit judgment unit, and the signal output terminal of the ground short circuit judgment unit is connected to the second enable signal input terminal of the switch management module.

7. The KVM extender automatic identification circuit according to claim 6, characterized in that, The short-circuit to ground detection unit includes MOSFET HQ20 and MOSFET HQ19. The first conducting terminal of MOSFET HQ20 is connected to a 3.3V power supply, and the second conducting terminal of MOSFET HQ20 is grounded. The controlled terminal of MOSFET HQ20 is connected to a second signal node. The first conducting terminal of MOSFET HQ19 is connected to output a second enable signal, and the second conducting terminal of MOSFET HQ19 is grounded. A corresponding third signal node is formed between the first conducting terminal of MOSFET HQ20 and the 3.3V power supply. The controlled terminal of MOSFET HQ19 is connected to the third signal node, and the third signal node is connected to the first signal node, so as to output the second enable signal to the switch conduction unit.

8. The KVM extender automatic identification circuit according to claim 6, characterized in that, The detection unit includes at least one first detection resistor and at least one stabilizing capacitor. The first end of the first detection resistor is connected to the level detection port, the second end of the first detection resistor is connected to the first end of the stabilizing capacitor, and the second end of the stabilizing capacitor is grounded.

9. The KVM extender automatic identification circuit according to claim 6, characterized in that, The second signal node is connected to the signal input terminal of the short-circuit to ground detection unit through a second detection resistor.

10. A method for automatic identification of KVM extenders, characterized in that, An automatic identification circuit for a KVM extender as described in any one of claims 1-9, wherein the automatic identification method for a KVM extender comprises: Obtain the voltage amplitude information of the target detection line in the RJ45 interface module, and compare the voltage amplitude information with a preset amplitude threshold to generate a corresponding comparison result; Obtain the link status indicator light information of the RJ45 interface module, and generate a corresponding first enable signal based on the link status indicator light information and the comparison result; Based on the level amplitude information, a judgment result is generated to determine whether a short circuit to ground has occurred. When all the judgment results are normal results indicating that no short circuit to ground has occurred, a conduction enable signal is generated; otherwise, a disconnect enable signal is generated. The second enable signal includes the conduction enable signal and the disconnect enable signal. Based on the first enable signal and the second enable signal, the control switch management module executes the corresponding switching action.

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