Legality detection method and power supply equipment for Ethernet power supply system

Abstract

The present application discloses a method for detecting the legitimacy of an Ethernet power supply system, including: providing a first voltage signal at a power supply port and detecting the port voltage; when the port voltage is greater than a first preset voltage signal, providing a first preset voltage signal at the power supply port and detecting the port voltage and port current until they are stable, obtaining a first steady-state voltage and a first steady-state current; providing a second power supply signal at the power supply port, the second power supply signal is different from the first voltage signal, detecting the port voltage and port current of the power supply port until the port voltage and port current of the power supply port reach a stable state, obtaining a second steady-state voltage, a second steady-state current, multiple discharge voltage values ​​and discharge time; obtaining the signature impedance of a powered device according to the first steady-state voltage, the first steady-state current, the second steady-state voltage, the second steady-state current, multiple discharge voltage values ​​and discharge time. The present application also provides a power supply device that can quickly and accurately obtain the signature impedance of a powered device.

Description

Technical Field

[0001] The present invention relates to Ethernet power supply technology, and more specifically, to a legitimacy detection method and power supply equipment for an Ethernet power supply system. Background Art

[0002] Power over Ethernet (POE) technology refers to the technology of providing DC power to terminal devices in the network through network cables based on the existing Ethernet cabling infrastructure. In the Ethernet power supply technology, the network cable has the functions of transmitting data signals and DC power supply. This technology makes the terminal devices no longer need to rely on external power adapters for power supply, thus eliminating the need for power adapters, power cables and plugs, saving wiring and hardware costs.

[0003] The Ethernet power supply system includes power sourcing equipment (Power Sourcing Equipment, PSE) and powered devices (Powered Device, PD). The POE protocol standard (such as IEEE802.3af) defines that the Ethernet power supply system transmits power from the power sourcing equipment (Power Sourcing Equipment, PSE) to the powered device (Powered Device, PD) located on the opposite side of the link through an unshielded twisted pair cable.

[0004] As defined in the POE protocol standard, the power supply equipment PSE and the powered device PD are non-data entities that allow network devices to be powered and obtain power using the same cables used for data transmission. The power supply equipment PSE is a device that is electrically connected to the cable at the physical connection point, and it supplies power to the link. The powered device PD is a device that obtains or requests power.

[0005] The main function of the power supply equipment PSE is to search for links for the powered device PD requesting power, optionally classify the powered device PD, and if the powered device PD is detected, the power supply equipment PSE supplies power to the link, monitors the power supply on the link, and cuts off the power when it is no longer requested and needed. The power supply equipment PSE detects the signature impedance of the powered device PD and determines whether the signature impedance is within the range set by the POE protocol standard. If the signature impedance is within the range set by the POE protocol standard, the powered device PD is determined to be a legitimate device, and then the power supply equipment PSE can supply power to the powered device PD.

[0006] However, some powered devices (PDs) manufactured before the approval of the POE protocol standard cannot provide signature impedance that complies with the standard protocol to the power supply equipment (PSE) during the detection process. Such powered devices (PDs) are called traditional powered devices (PDs). For example, the signature impedance provided by some traditional powered PDs during the detection process may exist in many different forms, such as pure resistance, pure capacitance, resistance and capacitance in parallel, etc., and the range of signature resistance and capacitance is no longer limited to the range of the POE standard protocol.

[0007] Although it is desired to provide power to traditional powered devices PD, they will be determined as illegal devices during the conventional PD detection process, so the PSE will not power the PD device. Therefore, a PD detection solution that supports detecting traditional powered devices PD is required. Summary of the invention

[0008] In view of the above problems, an object of the present invention is to provide a method for detecting the legitimacy of an Ethernet power supply system and a power supply device, which can quickly and accurately obtain the signature impedance of a powered device.

[0009] According to one aspect of the present invention, a method for detecting the legitimacy of an Ethernet power supply system is provided, wherein the Ethernet power supply system includes a power supply port, comprising: providing a first power supply signal at the power supply port, the first power supply signal being a first voltage signal, and detecting a port voltage of the power supply port, the first voltage signal being greater than a first preset voltage signal; when the port voltage of the power supply port is greater than the first preset voltage signal, providing a first preset voltage signal at the power supply port, and detecting a port voltage and a port current of the power supply port until the port voltage and the port current of the power supply port reach a stable state, thereby obtaining a first steady-state voltage and a first steady-state current; providing a second power supply signal at the power supply port, the second power supply signal being different from the first voltage signal, detecting a port voltage and a port current of the power supply port until the port voltage and the port current of the power supply port reach a stable state, thereby obtaining a second steady-state voltage and a second steady-state current, a plurality of discharge voltage values ​​and a discharge time; and obtaining a signature impedance of a powered device according to the first steady-state voltage, the first steady current, the second steady voltage, the second steady current, the plurality of discharge voltage values ​​and the discharge time.

[0010] Preferably, when the second power supply signal is a first current signal, the legitimacy detection method further includes:

[0011] Detect the port voltage of the power supply port after a first preset time; when the port voltage of the power supply port is less than a threshold voltage, detect the port voltage and port current of the power supply port until the port voltage and port current of the power supply port reach a stable state, and obtain a second steady-state voltage and a second steady-state current, multiple discharge voltage values ​​and a discharge time; obtain the signature impedance of the powered device according to the first steady-state voltage, the first steady-state current, the second steady-state voltage and the second steady-state current, the multiple discharge voltage values, the first current signal and the discharge time.

[0012] Preferably, the legitimacy detection method also includes: when the port voltage of the power supply port is greater than a threshold voltage, providing a third power supply signal at the power supply port, the third power supply signal is a second voltage signal, and detecting the port voltage of the power supply port, wherein the second voltage signal is greater than the first voltage signal; when the port voltage of the power supply port is greater than a second preset voltage signal, providing a second preset voltage signal at the power supply port, and detecting the port voltage and port current of the power supply port until the port voltage and port current of the power supply port reach a stable state, thereby obtaining a third steady-state voltage and a third steady-state current; providing a second current signal at the power supply port, detecting the port voltage and port current of the power supply port to obtain multiple charging voltage values ​​and charging time; and obtaining the signature impedance of the powered device according to the first steady-state voltage, the first steady-state current, the third steady-state voltage and the third steady-state current, the multiple charging voltage values ​​and the charging time.

[0013] Preferably, the first current signal is half of the first steady-state current.

[0014] Preferably, the second current signal is N times the third steady-state current, wherein N is a positive number greater than 1.

[0015] Preferably, obtaining the signature impedance of the powered device according to the first steady-state voltage, the first steady-state current, the second steady-state voltage and the second steady-state current and multiple discharge voltage values ​​and discharge times includes: obtaining the signature resistance of the powered device according to the first steady-state voltage, the first steady-state current, the second steady-state voltage and the second steady current; obtaining the signature capacitance of the powered device according to the multiple discharge voltage values, the first current signal, the discharge time and the signature resistance.

[0016] Preferably, obtaining the signature impedance of the powered device according to the first steady-state voltage, the first steady-state current, the third steady-state voltage and the third steady-state current and multiple charging voltage values ​​includes: obtaining the signature resistance of the powered device according to the first steady-state voltage, the first steady-state current, the third steady-state voltage and the third steady-state current; obtaining the signature capacitance of the powered device according to the multiple charging voltage values, the second current signal, the charging time and the signature resistance.

[0017] Preferably, the legitimacy detection method further comprises: determining whether to supply power to the powered device according to the signature impedance of the powered device.

[0018] Preferably, the legitimacy detection method also includes: determining whether the port voltage of the power supply port is less than the initial voltage signal; when the port voltage of the power supply port is less than the initial voltage signal, providing the initial voltage signal at the power supply port until the port voltage and port current of the power supply port reach a steady state.

[0019] According to another aspect of the present invention, a power supply device of an Ethernet system is provided, wherein the Ethernet power supply system includes a power supply port, including: a first detection power supply connected to the power supply port and used to provide a voltage signal to the power supply port; a second detection power supply connected to the power supply port and used to provide a current signal to the power supply port; a controller connected to the first detection power supply, the second detection power supply and the power supply port, and used to control the first detection power supply to provide a first power supply signal to the power supply port, wherein the first power supply signal is a first voltage signal, and detects a port voltage of the power supply port, wherein the first voltage signal is greater than a first preset voltage signal; wherein the controller is also used to control the first detection power supply to provide a first power supply signal to the power supply port when the port voltage of the power supply port is greater than the first preset voltage signal. The power supply port provides a first preset voltage signal, and detects the port voltage and port current of the power supply port until the port voltage and port current of the power supply port reach a stable state, thereby obtaining a first steady-state voltage and a first steady-state current; the controller is also used to control the second detection power supply to provide a second power supply signal to the power supply port, wherein the second power supply signal is different from the first voltage signal, and detects the port voltage and port current of the power supply port until the port voltage and port current of the power supply port reach a stable state, thereby obtaining a second steady-state voltage and a second steady-state current, multiple discharge voltage values ​​and discharge times; the controller is also used to obtain the signature impedance of the powered device according to the first steady-state voltage, the first steady-state current, the second steady voltage, the second steady current, the multiple discharge voltage values ​​and the discharge time.

[0020] Preferably, when the second power supply signal is the first current signal, the controller is also used to detect whether the port voltage of the power supply port is less than a threshold voltage after a first preset time; the controller is also used to detect the port voltage and port current of the power supply port when the port voltage of the power supply port is less than the threshold voltage until the port voltage and port current of the power supply port reach a stable state, and obtain a second steady-state voltage and a second steady-state current as well as multiple discharge voltage values ​​and discharge times; the controller is also used to obtain the signature impedance of the powered device according to the first steady-state voltage, the first steady-state current, the second steady-state voltage and the second steady-state current, multiple discharge voltage values, the first current signal and the discharge time.

[0021] Preferably, the controller includes: a voltage detection unit, used to obtain the port voltage of the power supply port; a current detection unit, used to obtain the port current of the power supply port; a control unit, used to control the first detection power supply to provide a first power supply signal to the power supply port, wherein the first power supply signal is a first voltage signal, and the port voltage of the power supply port is detected by the voltage detection unit, and the first voltage signal is greater than a first preset voltage signal; the control unit is also used to determine whether the port voltage of the power supply port is greater than the first preset voltage signal; the control unit is also used to provide a first preset voltage signal at the power supply port when the port voltage of the power supply port is greater than the first preset voltage signal, and detect the port voltage of the power supply port by the voltage detection unit and detect the port current of the power supply port by the current detection unit until the port voltage and port current of the power supply port reach a stable state, thereby obtaining a first steady-state voltage and a first steady-state current; the control unit The control unit is also used to control the second detection power supply to provide a second power supply signal to the power supply port, where the second power supply signal is a first current signal, and the port voltage of the power supply port after the first preset time is detected by the voltage detection unit; the control unit is also used to determine whether the port voltage of the power supply port is less than a threshold voltage after the first preset time; the control unit is also used to detect the port voltage of the power supply port through the voltage detection unit and the port current of the power supply port through the current detection unit when the port voltage of the power supply port is less than the threshold voltage until the port voltage and the port current of the power supply port reach a stable state, and obtain a second steady-state voltage and a second steady-state current, multiple discharge voltage values ​​and a discharge time; the control unit is also used to obtain the signature impedance of the powered device according to the first steady-state voltage, the first steady-state current, the second steady-state voltage and the second steady-state current, the multiple discharge voltage values, the first current signal and the discharge time.

[0022] Preferably, the control unit is also used to provide a third power supply signal at the power supply port when the port voltage of the power supply port is greater than a threshold voltage, the third power supply signal is a second voltage signal, and the port voltage of the power supply port is detected by the voltage detection unit, wherein the second voltage signal is greater than the first voltage signal; and when the port voltage of the power supply port is greater than a second preset voltage signal, a second preset voltage signal is provided at the power supply port, and the port voltage of the power supply port is detected by the voltage detection unit and the port current of the power supply port is detected by the current detection unit until the port voltage and the port current of the power supply port reach a stable state, thereby obtaining a third steady-state voltage and a third steady-state current; the control unit is also used to provide a second current signal at the power supply port, detect the port voltage of the power supply port by the voltage detection unit and detect the current of the power supply port by the current detection unit to obtain multiple charging voltage values ​​and charging time; the control unit is also used to obtain the signature impedance of the powered device according to the first steady-state voltage, the first steady-state current, the third steady-state voltage and the third steady-state current, multiple charging voltage values, the second current signal and the charging time.

[0023] Preferably, the first current signal is half of the first steady-state current.

[0024] Preferably, the second current signal is N times the third steady-state current, wherein N is a positive number greater than 1.

[0025] Preferably, the control unit is used to obtain the signature resistance of the powered device according to the first steady-state voltage, the first steady-state current, the second steady-state voltage and the second steady-state current; and to obtain the signature capacitance of the powered device according to the multiple discharge voltage values, the first current signal, the discharge time and the signature resistance.

[0026] Preferably, the acquisition unit is used to acquire the signature resistance of the powered device according to the first steady-state voltage, the first steady-state current, the third steady-state voltage and the third steady-state current; and to acquire the signature capacitance of the powered device according to the multiple charging voltage values, the second current signal, the charging time and the signature resistance.

[0027] Preferably, the control unit is further used to determine whether to supply power to the powered device according to the signature impedance of the powered device.

[0028] Preferably, the control unit is also used to determine whether the port voltage of the power supply port is less than the initial voltage signal; the control unit is also used to control the first detection power supply to provide an initial voltage signal at the power supply port until the port voltage and port current of the power supply port reach a steady state when the port voltage of the power supply port is less than the initial voltage signal.

[0029] According to a third aspect of the present invention, a method for detecting the legitimacy of an Ethernet power supply system is provided, wherein the Ethernet power supply system includes a power supply port, comprising: providing a first voltage signal at the power supply port, and detecting a port voltage of the power supply port, wherein the first voltage signal is greater than a first preset voltage signal; when the port voltage of the power supply port is greater than the first preset voltage signal, providing a first preset voltage signal at the power supply port, and detecting the port voltage and port current of the power supply port until the port voltage and port current of the power supply port reach a stable state, thereby obtaining a first steady-state voltage and a first steady-state current; providing a second voltage signal at the power supply port, and detecting the port voltage of the power supply port. , wherein the second voltage signal is greater than the first voltage signal; when the port voltage of the power supply port is greater than the second preset voltage signal, the second preset voltage signal is provided at the power supply port, and the port voltage and port current of the power supply port are detected until the port voltage and port current of the power supply port reach a stable state, and a third steady-state voltage and a third steady-state current are obtained; a second current signal is provided at the power supply port, and the port voltage and port current of the power supply port are detected to obtain multiple charging voltage values ​​and charging times; the signature impedance of the powered device is obtained according to the first steady-state voltage, the first steady-state current, the third steady-state voltage and the third steady-state current, the multiple charging voltage values, the second current signal and the charging time.

[0030] Preferably, obtaining the signature impedance of the powered device according to the first steady-state voltage, the first steady-state current, the third steady-state voltage and the third steady-state current, multiple charging voltage values, the second current signal and the charging time includes: obtaining the signature resistance of the powered device according to the first steady-state voltage, the first steady-state current, the third steady-state voltage and the third steady-state current; obtaining the signature capacitance of the powered device according to the multiple charging voltage values, the second current signal, the charging time and the signature resistance.

[0031] Preferably, the legitimacy detection method further comprises: determining whether to supply power to the powered device according to the signature impedance of the powered device.

[0032] Preferably, the legitimacy detection method also includes: determining whether the port voltage of the power supply port is less than the initial voltage signal; when the port voltage of the power supply port is less than the initial voltage signal, providing the initial voltage signal at the power supply port until the port voltage and port current of the power supply port reach a steady state.

[0033] According to a third aspect of the present invention, there is provided a power supply device of an Ethernet system, wherein the Ethernet power supply system includes a power supply port, including: a first detection power supply connected to the power supply port and used to provide a voltage signal to the power supply port; a second detection power supply connected to the power supply port and used to provide a current signal to the power supply port; a controller connected to the first detection power supply, the second detection power supply and the power supply port, and used to control the first detection power supply to provide a first voltage signal to the power supply port, and detect the port voltage of the power supply port, wherein the first voltage signal is greater than a first preset voltage signal; wherein the controller is also used to control the first detection power supply to provide the first preset voltage signal to the power supply port when the port voltage of the power supply port is greater than the first preset voltage signal, and detect the port voltage and port current of the power supply port until the port voltage and port current of the power supply port reach a stable state. state, obtaining a first steady-state voltage and a first steady-state current; the controller is also used to provide a second voltage signal at the power supply port and detect the port voltage of the power supply port, wherein the second voltage signal is greater than the first voltage signal; the controller is also used to provide a second preset voltage signal at the power supply port when the port voltage of the power supply port is greater than the second preset voltage signal, and detect the port voltage and port current of the power supply port until the port voltage and port current of the power supply port reach a stable state, thereby obtaining a third steady-state voltage and a third steady-state current; the controller is also used to provide a second current signal at the power supply port, detect the port voltage and port current of the power supply port to obtain multiple charging voltage values ​​and charging time; and obtain the signature impedance of the powered device according to the first steady-state voltage, the first steady-state current, the third steady-state voltage and the third steady-state current, multiple charging voltage values, the second current signal and the charging time.

[0034] Preferably, the controller includes: a voltage detection unit, used to obtain the port voltage of the power supply port; a current detection unit, used to obtain the port current of the power supply port; a control unit, used to control the first detection power supply to provide a first voltage signal to the power supply port, and detect the port voltage of the power supply port through the voltage detection unit, and the first voltage signal is greater than a first preset voltage signal; the control unit is also used to determine whether the port voltage of the power supply port is greater than the first preset voltage signal; the control unit is also used to provide a first preset voltage signal at the power supply port when the port voltage of the power supply port is greater than the first preset voltage signal, and detect the port voltage of the power supply port through the voltage detection unit and detect the port current of the power supply port through the current detection unit until the port voltage and port current of the power supply port reach a stable state, thereby obtaining a first steady-state voltage and a first steady-state current; the control unit is also used to provide a second voltage signal at the power supply port, and detect the port voltage of the power supply port through the current detection unit. The voltage detection unit detects the port voltage of the power supply port, wherein the second voltage signal is greater than the first voltage signal; and when the port voltage of the power supply port is greater than the second preset voltage signal, the second preset voltage signal is provided at the power supply port, and the port voltage of the power supply port is detected by the voltage detection unit and the port current of the power supply port is detected by the current detection unit until the port voltage and the port current of the power supply port reach a stable state, thereby obtaining a third steady-state voltage and a third steady-state current; the control unit is also used to provide a second current signal at the power supply port, detect the port voltage of the power supply port by the voltage detection unit and detect the current of the power supply port by the current detection unit to obtain multiple charging voltage values ​​and charging time; the control unit is also used to obtain the signature impedance of the powered device according to the first steady-state voltage, the first steady-state current, the third steady-state voltage and the third steady-state current, multiple charging voltage values, the second current signal and the charging time.

[0035] Preferably, the control unit is further used to determine whether to supply power to the powered device according to the signature impedance of the powered device.

[0036] Preferably, the control unit is also used to determine whether the port voltage of the power supply port is less than the initial voltage signal; the control unit is also used to control the first detection power supply to provide an initial voltage signal at the power supply port until the port voltage and port current of the power supply port reach a steady state when the port voltage of the power supply port is less than the initial voltage signal.

[0037] According to the legitimacy detection method and power supply device of the Ethernet power supply system of the embodiment of the present invention, by providing a first voltage signal at the power supply port and detecting the port voltage of the power supply port, the first voltage signal is greater than a first preset voltage signal; when the port voltage of the power supply port is greater than the first preset voltage signal, the first preset voltage signal is provided at the power supply port, regardless of whether the power supply port is connected to a traditional powered device or a standard powered device, the port current and port voltage can reach a steady state more quickly, so that the signature impedance of the powered device can be obtained quickly and accurately.

[0038] Furthermore, a first current signal is provided at the power supply port, and the port voltage of the power supply port is detected after a first preset time; whether the powered device has a large signature impedance is determined by judging whether the port voltage of the power supply port is less than a threshold voltage; when the port voltage of the power supply port is less than the threshold voltage, the powered device has a small signature impedance, and the port voltage and port current of the power supply port are detected until the port voltage and port current of the power supply port reach a stable state, thereby obtaining a second steady-state voltage and a second steady-state current as well as a plurality of discharge voltage values, which can simplify the detection process of the powered device with a small signature capacitor, thereby simplifying the detection process and reducing costs while meeting the detection speed and accuracy.

[0039] Furthermore, when the port voltage of the power supply port is greater than a threshold voltage, a second voltage signal is provided at the power supply port, and the port voltage of the power supply port is detected, wherein the second voltage signal is greater than the first voltage signal; when the port voltage of the power supply port is greater than a second preset voltage signal, a second preset voltage signal is provided at the power supply port, and the port voltage and port current of the power supply port are detected until the port voltage and port current of the power supply port reach a stable state, thereby obtaining a third steady-state voltage and a third steady-state current; a second current signal is provided at the power supply port, and the port voltage and port current of the power supply port are detected to obtain multiple charging voltage values ​​and charging times, thereby quickly and accurately detecting the signature impedance of a powered device with a large signature impedance. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0041] Figure 1 A schematic circuit diagram of a POE power supply system in the prior art is shown;

[0042] Figure 2 A flow chart showing a method for detecting legitimacy of a POE power supply system according to an embodiment of the present invention is shown;

[0043] Figure 3A waveform diagram showing a POE power supply system connected to a standard powered device according to an embodiment of the present invention;

[0044] Figure 4 A waveform diagram showing a POE power supply system connected to a conventional powered device according to an embodiment of the present invention; Figure 5 A schematic diagram showing the structure of a power supply device according to an embodiment of the present invention is shown;

[0045] Figure 6 A flow chart of a method for detecting the legitimacy of a POE power supply system according to another embodiment of the present invention is shown. DETAILED DESCRIPTION

[0046] Various embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. In each of the accompanying drawings, the same elements are represented by the same or similar reference numerals. For the sake of clarity, the various parts in the accompanying drawings are not drawn to scale.

[0047] The specific implementation of the present invention is further described in detail below in conjunction with the drawings and examples.

[0048] Figure 1 FIG. 1 shows a schematic circuit diagram of a POE power supply system 100 in the prior art. Figure 1 As shown, the POE power supply system 100 includes a power supply device 10 , a powered device 20 , and an interface unit 30 connected between the power supply device 10 and the powered device 20 .

[0049] Specifically, the power supply device 10 may be a switch, a hub or a router, etc., and the powered device 20 may be a wireless access point, a camera, an IP phone, a smart speaker, a smart light, a manipulator, a smart charger, etc. The power supply device 10 includes a power supply circuit 11, a controller 12 and a power supply port 13.

[0050] The powered device 20 includes a powered port 21, a powered control circuit 22, and a load 23. The powered port 21 is a bridge structure.

[0051] The interface unit 30 includes multiple transformers (T1-T2) connected to the power supply port 13, multiple transformers (T3-T4) connected to the power receiving port, and multiple power line pairs (P1-P2, P3-P4), each power supply port is connected to a pair of transformers, and each power receiving port is connected to a pair of transformers; wherein the power supply port 13 is respectively connected to the first transformer T1 and the second transformer T2; the power receiving port 21 is respectively connected to the third transformer T3 and the fourth transformer T4.

[0052] The first input end of the power receiving port 21 is connected to the center tap of the primary winding of the transformer connected to the first power supply line pair (P1-P2), and the second input end of the power receiving port 21 is connected to the center tap of the primary winding of the transformer connected to the second power supply line pair (P3-P4). That is, the first input end and the second input end of the power receiving port 21 are connected to the center tap of the primary winding of the third transformer T3 and the center tap of the primary winding of the fourth transformer T4, respectively.

[0053] The positive output terminal of the power receiving port 21 is connected to the positive input terminal of the power receiving control circuit 22, and the negative output terminal of the power receiving port 21 is connected to the negative input terminal of the power receiving control circuit 22. The power receiving control circuit 22 has a path from the positive input terminal to its positive output terminal and a path from the negative input terminal to its negative output terminal. The positive input terminal of the load 23 is connected to the positive output terminal of the power receiving control circuit 23.

[0054] The power supply device 10 may or may not be connected to the powered device 20 via the interface unit 30. Therefore, the power supply device 10 needs to detect its power supply port 13 to determine whether a powered device 20 is connected to the power supply port 13 of the power supply device 10 via the interface unit 30.

[0055] In the prior art, the legitimacy detection method first applies a constant current to the power supply port when a powered device is connected, which will cause the signature capacitance of the powered device 20 to be too high, so that the high voltage or residual voltage on the capacitor affects the subsequent detection results.

[0056] Figure 2 FIG. 1 is a flow chart showing a method for detecting the legitimacy of a POE power supply system according to an embodiment of the present invention. Figure 2 , the legitimacy detection method includes the following steps.

[0057] In step S111, the first power supply signal is provided as a first voltage signal at the power supply port, and the port voltage of the power supply port is detected, and the first voltage signal is greater than a first preset voltage signal.

[0058] In this embodiment, the first voltage signal is provided by the first detection power supply, has an amplitude of V1, and continuously detects the port voltage V of the power supply port 13. PSE , wherein the first voltage signal is greater than the first preset voltage signal, and the amplitude of the first preset voltage signal is Vs1, that is, V1>Vs1. For example, the amplitude of the first voltage signal V1=6V, and the amplitude of the first preset voltage signal Vs1=5V, but it is not limited thereto.

[0059] In step S112, it is determined whether the port voltage of the power supply port is greater than a first preset voltage signal.

[0060] Specifically, when the port voltage is greater than the first preset voltage signal, that is, V PSE >Vs1, execute step S113; when the port voltage is not greater than the first preset voltage signal, that is, V PSE ≤V1, execute step S111.

[0061] In step S113, when the port voltage of the power supply port is greater than the first preset voltage signal, a first preset voltage signal is provided at the power supply port, and the port voltage and port current of the power supply port are detected until the port voltage and port current of the power supply port reach a stable state, thereby obtaining a first steady-state voltage and a first steady-state current.

[0062] In this embodiment, when the port voltage of the power supply port 13 is greater than the first preset voltage signal (ie, V PSE >Vs1), the first detection power supply provides a first preset voltage signal to the power supply port 13, and continuously detects the port voltage V of the power supply port 13. PSE and port current I PSE Until the port voltage and the port current of the power supply port 13 reach a stable state, a first steady-state voltage and a first steady-state current are obtained; at this time, the port voltage V PSE and port current I PSE remains unchanged, at this time the port voltage V PSE =Vs1, port current I PSE =Is1, that is, the first steady-state voltage Vss1=Vs1, and the first steady-state current Iss1=Is1.

[0063] In the prior art, a preset voltage signal is directly applied. When the port voltage is very close to the steady-state value, the change amplitude of the port current is very small, so it takes a lot of time for the port current to reach the final steady-state current within a few microamperes. The steady-state error of a few microamperes may cause an error of up to 10% or more when calculating the signature resistance. Therefore, in order to reduce the error, the time waiting for the port current to reach the steady state will become very long. For a powered device with a large signature resistance and capacitance, it is also possible to directly use the threshold voltage judgment method to determine whether the powered device can pass the test without waiting for the port voltage to reach the steady-state value. However, a powered device with a large signature resistance cannot be detected.

[0064] Since a voltage signal larger than the preset voltage signal is first applied to the power supply port, and when the port voltage rises to the preset voltage signal, the preset voltage signal is provided to the power supply port, the port current and the port voltage can reach a steady state more quickly, thereby quickly and accurately obtaining the signature impedance of the powered device.

[0065] Specifically, during the port voltage rise process, since the steady-state voltage is greater than the first preset voltage signal during the first voltage signal application stage, the port voltage can quickly reach the first preset voltage signal. Since there is a hysteresis in voltage detection, when switching to apply the first preset voltage signal, the actual load port voltage will be greater than the first preset voltage signal. At this time, because the diode is in a reverse cutoff state, the charge on the large load capacitor will be quickly discharged through the detection resistor. In the case of an ideal unidirectional conductive characteristic of the diode, there will be no long tail time for capacitor charging, thereby greatly shortening the time to obtain steady-state voltage and current values ​​when detecting traditional power receiving equipment with large resistance and capacitance, and accelerating the detection speed and accuracy.

[0066] In step S114, a second power supply signal is provided at the power supply port, where the second power supply signal is a first current signal, and a port voltage of the power supply port is detected after a first preset time.

[0067] In this embodiment, the first current signal is provided by the second detection power supply, and the amplitude is I1, where I1=Iss1 / 2. The port voltage V PSE =V0. The first preset time Td is determined according to the discharge curve and the discharge time under constant current.

[0068] In step S115, it is determined whether the port voltage of the power supply port is less than a threshold voltage.

[0069] Specifically, when the port voltage is less than the threshold voltage, that is, V0<Vth, step S116 is executed; when the port voltage is not less than the threshold voltage, that is, V0≥Vth, step S118 is executed.

[0070] In step S116, the port voltage and the port current of the power supply port are detected until the port voltage and the port current of the power supply port reach a stable state, and a second steady-state voltage and a second steady-state current, a plurality of discharge voltage values ​​and a discharge time are obtained.

[0071] In this embodiment, when the port voltage is less than the threshold voltage (see Figure 3 ), that is, when V0<Vth, the port voltage is collected at regular intervals until the port voltage stabilizes, and a second steady-state voltage Vss2 and a second steady-state current Iss2, a plurality of discharge voltage values ​​Vdischarge and a discharge time are obtained, wherein Iss2=I1, Vss2≈Vs1 / 2.

[0072] In step S117, the signature impedance of the powered device is acquired according to the first steady-state voltage, the first steady-state current, the second steady-state voltage and the second steady-state current, a plurality of discharge voltage values, and a discharge time.

[0073] Specifically, the signature resistance of the powered device is obtained according to the first steady-state voltage Vss1, the first steady-state current Iss1, the second steady-state voltage Vss2 and the second steady-state current Iss2; the signature capacitance of the powered device is obtained according to the multiple discharge voltage values ​​Vdischarge, the first current signal I1, the discharge time and the signature resistance.

[0074] In step S118, a third power supply signal is provided at the power supply port, wherein the third power supply signal is a second voltage signal, and the port voltage of the power supply port is detected, wherein the second voltage signal is greater than the first voltage signal.

[0075] In this embodiment, when the port voltage is greater than the threshold voltage (see Figure 4 ), that is, when V0>Vth, a second voltage signal is provided at the power supply port, and the port voltage V of the power supply port 13 is continuously detected. PSE The second voltage signal is provided by the first detection power supply, has an amplitude of V2, and V2>V1, and the second preset voltage signal can be the same as the first voltage signal. For example, the amplitude of the second voltage signal V2=7V, the second preset voltage signal Vs2=V1=6V, but it is not limited thereto.

[0076] In step S119, it is determined whether the port voltage of the power supply port is greater than a second preset voltage signal.

[0077] Specifically, when the port voltage is greater than the second preset voltage signal, that is, V PSE >Vs2, execute step S120; when the port voltage is not greater than the second preset voltage signal, that is, V PSE ≤Vs2, execute step S118.

[0078] In step S120, a second preset voltage signal is provided at the power supply port, and the port voltage and the port current of the power supply port are detected until the port voltage and the port current of the power supply port reach a stable state, thereby obtaining a third steady-state voltage and a third steady-state current.

[0079] In this embodiment, when the port voltage of the power supply port 13 is greater than the second preset voltage signal (ie, V PSE >Vs2), the first detection power supply provides a second preset voltage signal to the power supply port 13, and continuously detects the port voltage V of the power supply port 13. PSE and port current I PSE Until the port voltage and the port current of the power supply port 13 reach a stable state, a second steady-state voltage and a second steady-state current are obtained; at this time, the port voltage V PSE and port current I PSE remains unchanged, at this time the port voltage V PSE=Vs2=V1, port current I PSE =Is3, that is, the third steady-state voltage Vss2=Vs2=V1, and the third steady-state current Iss3=Is3.

[0080] In step S121, a second current signal is provided at the power supply port, and a port voltage and a port current of the power supply port are detected to obtain a plurality of charging voltage values ​​and charging times.

[0081] In this embodiment, the second current signal is provided by the second detection power supply, and the amplitude is I2, where I2=N*Iss3, where N is a positive number greater than 1. For example, N=1.2 but not limited thereto. The port voltage is collected at regular intervals until the port voltage is stable, and a plurality of charging voltage values ​​Vcharge and charging times are obtained.

[0082] In step S122, the signature impedance of the powered device is acquired according to the first steady-state voltage, the first steady-state current, the third steady-state voltage and the third steady-state current, a plurality of charging voltage values, the second current signal, and the charging time.

[0083] Specifically, the signature resistance of the powered device is obtained according to the first steady-state voltage Vss1, the first steady-state current Iss1, the third steady-state voltage Vss3 and the third steady-state current Iss3; the signature capacitance of the powered device is obtained according to the multiple charging voltage values ​​Vcharge, the second current signal I2, the signature resistance and the charging time.

[0084] In a preferred embodiment, steps S101 and S102 are further included before step S111.

[0085] In step S101, it is determined whether the port voltage of the power supply port is less than an initial voltage signal.

[0086] Specifically, when the port voltage of the power supply port is less than the initial voltage signal, step S102 is performed. When the port voltage of the power supply port is greater than the initial voltage signal, step S101 is always performed. The amplitude of the initial voltage signal is Vs0, for example, 3V, but not limited thereto.

[0087] In step S102, an initial voltage signal is provided at the power supply port until the port voltage and the port current of the power supply port reach a steady state, and then step S111 is performed. In a preferred embodiment, step S123 is further included after step S117 or step S122.

[0088] In step S123 , it is determined whether to supply power to the powered device according to the signature impedance of the powered device.

[0089] Specifically, it is determined whether the signature impedance of the powered device is within a preset impedance range, and when the signature impedance of the powered device is within the preset impedance range, it is determined to supply power to the powered device.

[0090] The preset impedance range may be a preset impedance range of a standard powered device, or may be a preset impedance range including a standard powered device and a traditional powered device.

[0091] The legitimacy detection method of the Ethernet power supply system provided by the embodiment of the present invention provides a first voltage signal at the power supply port and detects the port voltage of the power supply port, wherein the first voltage signal is greater than a first preset voltage signal; when the port voltage of the power supply port is greater than the first preset voltage signal, the first preset voltage signal is provided at the power supply port. Regardless of whether the power supply port is connected to a traditional powered device or a standard powered device, the port current and port voltage can reach a steady state more quickly, thereby quickly and accurately obtaining the signature impedance of the powered device.

[0092] Furthermore, a first current signal is provided at the power supply port, and the port voltage of the power supply port is detected after a first preset time; whether the powered device has a large signature impedance is determined by judging whether the port voltage of the power supply port is less than a threshold voltage; when the port voltage of the power supply port is less than the threshold voltage, the powered device has a small signature impedance, and the port voltage and port current of the power supply port are detected until the port voltage and port current of the power supply port reach a stable state, thereby obtaining a second steady-state voltage and a second steady-state current as well as a plurality of discharge voltage values, which can simplify the detection process of the powered device with a small signature capacitor, thereby simplifying the detection process and reducing costs while meeting the detection speed and accuracy.

[0093] Furthermore, when the port voltage of the power supply port is greater than a threshold voltage, a second voltage signal is provided at the power supply port, and the port voltage of the power supply port is detected, wherein the second voltage signal is greater than the first voltage signal; when the port voltage of the power supply port is greater than a second preset voltage signal, a second preset voltage signal is provided at the power supply port, and the port voltage and port current of the power supply port are detected until the port voltage and port current of the power supply port reach a stable state, thereby obtaining a third steady-state voltage and a third steady-state current; a second current signal is provided at the power supply port, and the port voltage and port current of the power supply port are detected to obtain multiple charging voltage values ​​and charging times, thereby quickly and accurately detecting the signature impedance of a powered device with a large signature capacitor.

[0094] Figure 5 FIG. 2 shows a schematic diagram of the structure of a power supply device according to an embodiment of the present invention. Figure 5 The power supply device includes a power supply circuit 11, a controller 12 and a power supply port 13.

[0095] The power supply circuit 11 includes a first detection power supply 11 a and a second detection power supply 11 b .

[0096] In this embodiment, the first detection power supply 11a is connected to the power supply port 13 to provide a voltage signal to the power supply port.

[0097] The second detection power supply 11 b is connected to the power supply port 13 and is used to provide a current signal to the power supply port.

[0098] The controller 12 is connected to the first detection power supply 11a, the second detection power supply 11b and the power supply port 13 respectively, and is used to control the first detection power supply to provide a first voltage signal to the power supply port and detect the port voltage of the power supply port, wherein the first voltage signal is greater than a first preset voltage signal.

[0099] The controller 12 is also used to control the first detection power supply to provide a first preset voltage signal to the power supply port when the port voltage of the power supply port is greater than a first preset voltage signal, and detect the port voltage and port current of the power supply port until the port voltage and port current of the power supply port reach a stable state, thereby obtaining a first steady-state voltage and a first steady-state current.

[0100] The controller 12 is further configured to control the second detection power supply to provide a first current signal to the power supply port, and detect whether a port voltage of the power supply port is less than a threshold voltage after a first preset time.

[0101] The controller 12 is also used to detect the port voltage and port current of the power supply port when the port voltage of the power supply port is less than a threshold voltage until the port voltage and port current of the power supply port reach a stable state, thereby obtaining a second steady-state voltage and a second steady-state current and multiple discharge voltage values.

[0102] The controller 12 is further configured to obtain a signature impedance of the powered device according to the first steady-state voltage, the first steady-state current, the second steady-state voltage, the second steady-state current, and a plurality of discharge voltage values.

[0103] In this embodiment, the controller 12 includes a control unit 12a, a voltage detection unit 12b and a current detection unit 12c.

[0104] The voltage detection unit 12b is used to obtain the port voltage of the power supply port; and the current detection unit 12c is used to obtain the port current of the power supply port.

[0105] The control unit 12a is used to control the first detection power supply 11a to provide a first voltage signal to the power supply port, and detect the port voltage of the power supply port through the voltage detection unit 12b, and the first voltage signal is greater than a first preset voltage signal.

[0106] In this embodiment, the first voltage signal is provided by the first detection power supply 11a, has an amplitude of V1, and continuously detects the port voltage V of the power supply port 13. PSE , wherein the first voltage signal is greater than the first preset voltage signal, and the amplitude of the first preset voltage signal is Vs1, that is, V1>Vs1. For example, the amplitude of the first voltage signal V1=6V, and the amplitude of the first preset voltage signal Vs1=5V, but it is not limited thereto.

[0107] The control unit 12a is further configured to determine whether the port voltage of the power supply port is greater than a first preset voltage signal.

[0108] The control unit 12a is also used to provide a first preset voltage signal at the power supply port when the port voltage of the power supply port is greater than the first preset voltage signal, and detect the port voltage and port current of the power supply port until the port voltage and port current of the power supply port reach a stable state, thereby obtaining a first steady-state voltage and a first steady-state current.

[0109] In this embodiment, when the port voltage of the power supply port 13 is greater than the first preset voltage signal (ie, V PSE >Vs1), the first detection power supply 11a provides a first preset voltage signal to the power supply port 13, and continuously detects the port voltage V PSE and port current I PSE Until the port voltage and the port current of the power supply port 13 reach a stable state, a first steady-state voltage and a first steady-state current are obtained; at this time, the port voltage V PSE and port current I PSE remains unchanged, at this time the port voltage V PSE =Vs1, port current I PSE =Is1, that is, the first steady-state voltage Vss1=Vs1, and the first steady-state current Iss1=Is1.

[0110] The control unit 12a is further configured to control the second detection power supply to provide a first current signal to the power supply port, and detect a port voltage of the power supply port after a first preset time.

[0111] In this embodiment, the first current signal is provided by the second detection power supply, and the amplitude is I1, where I1=Iss1 / 2. The port voltage V PSE=V0. The first preset time Td is determined according to the discharge curve and the discharge time under constant current.

[0112] The control unit 12a is further configured to determine whether the port voltage of the power supply port is less than a threshold voltage after a first preset time.

[0113] The control unit 12a is also used to detect the port voltage and port current of the power supply port when the port voltage of the power supply port is less than a threshold voltage until the port voltage and port current of the power supply port reach a stable state, and obtain a second steady-state voltage and a second steady-state current, multiple discharge voltage values ​​and a discharge time.

[0114] The control unit 12a is further configured to obtain the signature impedance of the powered device according to the first steady-state voltage, the first steady-state current, the second steady-state voltage and the second steady-state current, a plurality of discharge voltage values, the first current signal and the discharge time.

[0115] In this embodiment, when the port voltage is less than the threshold voltage (see Figure 3 ), that is, when V0<Vth, the port voltage is collected at regular intervals until the port voltage stabilizes, and a second steady-state voltage Vss2 and a second steady-state current Iss2 as well as a plurality of discharge voltage values ​​Vdischarge and discharge times are obtained, wherein Iss2=I1, Vss2≈Vs1 / 2.

[0116] The control unit 12a is also used to provide a second voltage signal at the power supply port when the port voltage of the power supply port is greater than a threshold voltage, and detect the port voltage of the power supply port through the voltage detection unit 12b, wherein the second voltage signal is greater than the first voltage signal; and when the port voltage of the power supply port is greater than a second preset voltage signal, provide a second preset voltage signal at the power supply port, detect the port voltage of the power supply port through the voltage detection unit 12b, and detect the port current of the power supply port through the current detection unit 12c until the port voltage and port current of the power supply port reach a stable state, thereby obtaining a third steady-state voltage and a third steady-state current.

[0117] In this embodiment, when the port voltage is greater than the threshold voltage (see Figure 4 ), that is, when V0>Vth, a second voltage signal is provided at the power supply port, and the port voltage V of the power supply port 13 is continuously detected. PSE The second voltage signal is provided by the first detection power supply, has an amplitude of V2, and V2>V1, and the second preset voltage signal can be the same as the first voltage signal. For example, the amplitude of the second voltage signal V2=7V, the second preset voltage signal Vs2=V1=6V, but it is not limited thereto.

[0118] When the port voltage of the power supply port 13 is greater than the second preset voltage signal (ie, V PSE >Vs2), the first detection power supply provides a second preset voltage signal to the power supply port 13, and continuously detects the port voltage V of the power supply port 13. PSE and port current I PSE Until the port voltage and the port current of the power supply port 13 reach a stable state, a second steady-state voltage and a second steady-state current are obtained; at this time, the port voltage V PSE and port current I PSE remains unchanged, at this time the port voltage V PSE =Vs2=V1, port current I PSE =Is3, that is, the third steady-state voltage Vss2=Vs2=V1, and the third steady-state current Iss3=Is3.

[0119] The control unit 12a is further used to provide a second current signal at the power supply port, detect the port voltage and port current of the power supply port to obtain multiple charging voltage values ​​and charging times.

[0120] In this embodiment, the second current signal is provided by the second detection power supply, and the amplitude is I2, where I2=N*Iss3, where N is a positive number greater than 1. For example, N=1.2 but not limited thereto. The port voltage is collected at regular intervals until the port voltage is stable, and a plurality of charging voltage values ​​Vcharge and charging times are obtained.

[0121] The control unit 12a is further configured to obtain a signature impedance of the powered device according to the first steady-state voltage, the first steady-state current, the third steady-state voltage and the third steady-state current, a plurality of charging voltage values, a second current signal and a charging time.

[0122] Specifically, the signature resistance of the powered device is obtained according to the first steady-state voltage Vss1, the first steady-state current Iss1, the third steady-state voltage Vss3 and the third steady-state current Iss3; the signature capacitance of the powered device is obtained according to the multiple charging voltage values ​​Vcharge, the second current signal I2, the charging time and the signature resistance.

[0123] The control unit 12a is further configured to determine whether the port voltage of the power supply port is less than an initial voltage signal.

[0124] The control unit 12a is further configured to control the first detection power supply to provide an initial voltage signal at the power port until the port voltage and the port current of the power port reach a steady state when the port voltage of the power port is less than the initial voltage signal.

[0125] The control unit 12a is further configured to determine whether to supply power to the powered device according to the signature impedance of the powered device.

[0126] Specifically, it is determined whether the signature impedance of the powered device is within a preset impedance range, and when the signature impedance of the powered device is within the preset impedance range, it is determined to supply power to the powered device.

[0127] The preset impedance range may be a preset impedance range of a standard powered device, or may be a preset impedance range including a standard powered device and a traditional powered device.

[0128] The power supply device of the Ethernet power supply system provided by the embodiment of the present invention provides a first voltage signal at the power supply port and detects the port voltage of the power supply port, wherein the first voltage signal is greater than a first preset voltage signal; when the port voltage of the power supply port is greater than the first preset voltage signal, the first preset voltage signal is provided at the power supply port. Regardless of whether the power supply port is connected to a traditional powered device or a standard powered device, the port current and the port voltage can reach a steady state more quickly, thereby quickly and accurately obtaining the signature impedance of the powered device.

[0129] Furthermore, a first current signal is provided at the power supply port, and the port voltage of the power supply port is detected after a first preset time; whether the powered device has a large signature capacitance is determined by judging whether the port voltage of the power supply port is less than a threshold voltage; when the port voltage of the power supply port is less than the threshold voltage, the powered device has a small signature capacitance; the port voltage and the port current of the power supply port are detected until the port voltage and the port current of the power supply port reach a stable state, and a second steady-state voltage and a second steady-state current as well as a plurality of discharge voltage values ​​are obtained, which can simplify the detection process of the powered device with a small signature capacitance, thereby simplifying the detection process while satisfying the detection speed and accuracy.

[0130] Furthermore, when the port voltage of the power supply port is greater than a threshold voltage, a second voltage signal is provided at the power supply port, and the port voltage of the power supply port is detected, wherein the second voltage signal is greater than the first voltage signal; when the port voltage of the power supply port is greater than a second preset voltage signal, a second preset voltage signal is provided at the power supply port, and the port voltage and port current of the power supply port are detected until the port voltage and port current of the power supply port reach a stable state, thereby obtaining a third steady-state voltage and a third steady-state current; a second current signal is provided at the power supply port, and the port voltage and port current of the power supply port are detected to obtain multiple charging voltage values ​​and charging times, thereby quickly and accurately detecting the signature impedance of a powered device with a large signature capacitor.

[0131] Figure 6 FIG. 2 is a flow chart showing a method for detecting the legitimacy of a POE power supply system according to another embodiment of the present invention. Figure 6, the legitimacy detection method includes the following steps.

[0132] In step S211, a first voltage signal is provided at the power supply port, and a port voltage of the power supply port is detected, wherein the first voltage signal is greater than a first preset voltage signal.

[0133] In this embodiment, the first voltage signal is provided by the first detection power supply, has an amplitude of V1, and continuously detects the port voltage V of the power supply port 13. PSE , wherein the first voltage signal is greater than the first preset voltage signal, and the amplitude of the first preset voltage signal is Vs1, that is, V1>Vs1. For example, the amplitude of the first voltage signal V1=6V, and the amplitude of the first preset voltage signal Vs1=5V, but it is not limited thereto.

[0134] In step S212, it is determined whether the port voltage of the power supply port is greater than a first preset voltage signal.

[0135] Specifically, when the port voltage is greater than the first preset voltage signal, that is, V PSE >Vs1, execute step S213; when the port voltage is not greater than the first preset voltage signal, that is, V PSE ≤V1, execute step S211.

[0136] In step S213, when the port voltage of the power supply port is greater than the first preset voltage signal, a first preset voltage signal is provided at the power supply port, and the port voltage and port current of the power supply port are detected until the port voltage and port current of the power supply port reach a stable state, thereby obtaining a first steady-state voltage and a first steady-state current.

[0137] In this embodiment, when the port voltage of the power supply port 13 is greater than the first preset voltage signal (ie, V PSE >Vs1), the first detection power supply provides a first preset voltage signal to the power supply port 13, and continuously detects the port voltage V of the power supply port 13. PSE and port current I PSE Until the port voltage and the port current of the power supply port 13 reach a stable state, a first steady-state voltage and a first steady-state current are obtained; at this time, the port voltage V PSE and port current I PSE remains unchanged, at this time the port voltage V PSE =Vs1, port current I PSE =Is1, that is, the first steady-state voltage Vss1=Vs1, and the first steady-state current Iss1=Is1.

[0138] In the prior art, a preset voltage signal is directly applied. When the port voltage is very close to the steady-state value, the change amplitude of the port current is very small, so it takes a lot of time for the port current to reach the final steady-state current within a few microamperes. The steady-state error of a few microamperes may cause an error of up to 10% or more when calculating the signature resistance. Therefore, in order to reduce the error, the time waiting for the port current to reach the steady state will become very long. For a powered device with a large signature resistance and capacitance, it is also possible to directly use the threshold voltage judgment method to determine whether the powered device can pass the test without waiting for the port voltage to reach the steady-state value. However, a powered device with a large signature resistance cannot be detected.

[0139] Since a voltage signal larger than the preset voltage signal is first applied to the power supply port, and when the port voltage rises to the preset voltage signal, the preset voltage signal is provided to the power supply port, the port current and the port voltage can reach a steady state more quickly, thereby quickly and accurately obtaining the signature impedance of the powered device.

[0140] Specifically, during the port voltage rise process, since the steady-state voltage is greater than the first preset voltage signal during the first voltage signal application stage, the port voltage can quickly reach the first preset voltage signal. Since there is a hysteresis in voltage detection, when switching to apply the first preset voltage signal, the actual load port voltage will be greater than the first preset voltage signal. At this time, because the diode is in a reverse cutoff state, the charge on the large load capacitor will be quickly discharged through the detection resistor. In the case of an ideal unidirectional conductive characteristic of the diode, there will be no long tail time for capacitor charging, thereby greatly shortening the time to obtain steady-state voltage and current values ​​when detecting traditional power receiving equipment with large resistance and capacitance, and accelerating the detection speed and accuracy.

[0141] In step S214, a second voltage signal is provided at the power supply port, and a port voltage of the power supply port is detected, wherein the second voltage signal is greater than the first voltage signal.

[0142] In this embodiment, a second voltage signal is provided at the power supply port, and the port voltage V of the power supply port 13 is continuously detected. PSE The second voltage signal is provided by the first detection power supply, has an amplitude of V2, and V2>V1, and the second preset voltage signal can be the same as the first voltage signal. For example, the amplitude of the second voltage signal V2=7V, the second preset voltage signal Vs2=V1=6V, but it is not limited thereto.

[0143] In step S215, it is determined whether the port voltage of the power supply port is greater than a second preset voltage signal.

[0144] Specifically, when the port voltage is greater than the second preset voltage signal, that is, V PSE>Vs2, execute step S216; when the port voltage is not greater than the second preset voltage signal, that is, V PSE ≤Vs2, execute step S214.

[0145] In step S216, a second preset voltage signal is provided at the power supply port, and the port voltage and the port current of the power supply port are detected until the port voltage and the port current of the power supply port reach a stable state, thereby obtaining a third steady-state voltage and a third steady-state current.

[0146] In this embodiment, when the port voltage of the power supply port 13 is greater than the second preset voltage signal (ie, V PSE >Vs2), the first detection power supply provides a second preset voltage signal to the power supply port 13, and continuously detects the port voltage V of the power supply port 13. PSE and port current I PSE Until the port voltage and the port current of the power supply port 13 reach a stable state, a second steady-state voltage and a second steady-state current are obtained; at this time, the port voltage V PSE and port current I PSE remains unchanged, at this time the port voltage V PSE =Vs2=V1, port current I PSE =Is3, that is, the third steady-state voltage Vss2=Vs2=V1, and the third steady-state current Iss3=Is3.

[0147] In step S217, a second current signal is provided at the power supply port, and a port voltage and a port current of the power supply port are detected to obtain a plurality of charging voltage values ​​and charging times.

[0148] In this embodiment, the second current signal is provided by the second detection power supply, and the amplitude is I2, where I2=N*Iss3, where N is a positive number greater than 1. For example, N=1.2 but not limited thereto. The port voltage is collected at regular intervals until the port voltage is stable, and a plurality of charging voltage values ​​Vcharge and charging times are obtained.

[0149] In step S218, the signature impedance of the powered device is acquired according to the first steady-state voltage, the first steady-state current, the third steady-state voltage and the third steady-state current, a plurality of charging voltage values, a second current signal and a charging time.

[0150] Specifically, the signature resistance of the powered device is obtained according to the first steady-state voltage Vss1, the first steady-state current Iss1, the third steady-state voltage Vss3 and the third steady-state current Iss3; the signature capacitance of the powered device is obtained according to the multiple charging voltage values ​​Vcharge, the second current signal I2, the signature resistance and the charging time.

[0151] In a preferred embodiment, steps S201 and S202 are further included before step S211.

[0152] In step S201, it is determined whether the port voltage of the power supply port is less than an initial voltage signal.

[0153] Specifically, when the port voltage of the power supply port is less than the initial voltage signal, step S202 is performed. When the port voltage of the power supply port is greater than the initial voltage signal, step S201 is always performed. The amplitude of the initial voltage signal is Vs0, for example, 3V, but not limited thereto.

[0154] In step S202, an initial voltage signal is provided at the power supply port until the port voltage and the port current of the power supply port reach a steady state, and then step S211 is performed.

[0155] In a preferred embodiment, step S219 is further included after step S218.

[0156] In step S219 , it is determined whether to supply power to the powered device according to the signature impedance of the powered device.

[0157] Specifically, it is determined whether the signature impedance of the powered device is within a preset impedance range, and when the signature impedance of the powered device is within the preset impedance range, it is determined to supply power to the powered device.

[0158] The preset impedance range may be a preset impedance range of a standard powered device, or may be a preset impedance range including a standard powered device and a traditional powered device.

[0159] The legitimacy detection method of the Ethernet power supply system provided by the embodiment of the present invention provides a first voltage signal at the power supply port and detects the port voltage of the power supply port, wherein the first voltage signal is greater than a first preset voltage signal; when the port voltage of the power supply port is greater than the first preset voltage signal, the first preset voltage signal is provided at the power supply port. Regardless of whether the power supply port is connected to a traditional powered device or a standard powered device, the port current and port voltage can reach a steady state more quickly, thereby quickly and accurately obtaining the signature impedance of the powered device.

[0160] Correspondingly, the embodiment of the present invention also provides a power supply device, whose structure is similar to Figure 5 The structures of the power supply devices shown are identical, the difference lies in the function of the controller 12 .

[0161] In this embodiment, the controller 12 is respectively connected to the first detection power supply, the second detection power supply and the power supply port, and is used to control the first detection power supply to provide a first voltage signal to the power supply port and detect the port voltage of the power supply port, and the first voltage signal is greater than the first preset voltage signal.

[0162] The controller 12 is also used to control the first detection power supply to provide a first preset voltage signal to the power supply port when the port voltage of the power supply port is greater than a first preset voltage signal, and detect the port voltage and port current of the power supply port until the port voltage and port current of the power supply port reach a stable state, thereby obtaining a first steady-state voltage and a first steady-state current.

[0163] The controller 12 is also used to provide a second voltage signal at the power supply port and detect the port voltage of the power supply port, wherein the second voltage signal is greater than the first voltage signal; the controller is also used to provide a second preset voltage signal at the power supply port when the port voltage of the power supply port is greater than the second preset voltage signal, and detect the port voltage and port current of the power supply port until the port voltage and port current of the power supply port reach a stable state, thereby obtaining a third steady-state voltage and a third steady-state current.

[0164] The controller 12 is also used to provide a second current signal at the power supply port, detect the port voltage and port current of the power supply port to obtain multiple charging voltage values ​​and charging time; and obtain the signature impedance of the powered device according to the first steady-state voltage, the first steady-state current, the third steady-state voltage and the third steady-state current, multiple charging voltage values, the second current signal and the charging time.

[0165] The controller 12 includes a control unit 12a, a voltage detection unit 12b and a current detection unit 12c. The voltage detection unit 12b is used to obtain the port voltage of the power supply port; the current detection unit 12c is used to obtain the port current of the power supply port.

[0166] The control unit 12a is used to control the first detection power supply 11a to provide a first voltage signal to the power supply port, and detect the port voltage of the power supply port through the voltage detection unit 12b, and the first voltage signal is greater than a first preset voltage signal.

[0167] The control unit 12a is further configured to determine whether the port voltage of the power supply port is greater than a first preset voltage signal.

[0168] The control unit 12a is also used to provide a first preset voltage signal at the power supply port when the port voltage of the power supply port is greater than the first preset voltage signal, and detect the port voltage and port current of the power supply port until the port voltage and port current of the power supply port reach a stable state, thereby obtaining a first steady-state voltage and a first steady-state current.

[0169] The control unit 12a provides a second voltage signal at the power supply port, and detects the port voltage of the power supply port through the voltage detection unit 12b, wherein the second voltage signal is greater than the first voltage signal; and when the port voltage of the power supply port is greater than a second preset voltage signal, a second preset voltage signal is provided at the power supply port, and the port voltage of the power supply port is detected through the voltage detection unit 12b, and the port current of the power supply port is detected through the current detection unit 12c until the port voltage and the port current of the power supply port reach a stable state, thereby obtaining a third steady-state voltage and a third steady-state current.

[0170] The control unit 12a is further used to provide a second current signal at the power supply port, detect the port voltage and port current of the power supply port to obtain multiple charging voltage values ​​and charging times.

[0171] The control unit 12a is further configured to obtain a signature impedance of the powered device according to the first steady-state voltage, the first steady-state current, the third steady-state voltage and the third steady-state current, a plurality of charging voltage values, a second current signal and a charging time.

[0172] The control unit 12a is further configured to determine whether the port voltage of the power supply port is less than an initial voltage signal.

[0173] The control unit 12a is further configured to control the first detection power supply to provide an initial voltage signal at the power port until the port voltage and the port current of the power port reach a steady state when the port voltage of the power port is less than the initial voltage signal.

[0174] The control unit 12a is also used to determine whether to supply power to the powered device according to the signature impedance of the powered device. According to the embodiments of the present invention as described above, these embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and changes can be made based on the above description. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can make good use of the present invention and the modified use based on the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for detecting the legitimacy of an Ethernet power supply system, wherein: The Ethernet power supply system includes a power supply device, a powered device and an interface unit connected therebetween, wherein the power supply device includes a power supply port and is characterized in that it includes: Providing a first power supply signal at the power supply port, wherein the first power supply signal is a first voltage signal, and detecting a port voltage of the power supply port, wherein the first voltage signal is greater than a first preset voltage signal; When the port voltage of the power supply port is greater than the first preset voltage signal, the first preset voltage signal is provided at the power supply port, and the port voltage and the port current of the power supply port are detected until the port voltage and the port current of the power supply port reach a first stable state, and a first steady-state voltage and a first steady-state current are obtained, wherein the first stable state is a state in which the first steady-state voltage is equal to the amplitude of the first preset voltage signal; Providing a second power supply signal at the power supply port, the second power supply signal is different from the first voltage signal, the second power supply signal is a first current signal, and detecting the port voltage of the power supply port after a first preset time; When the port voltage of the power supply port is less than the threshold voltage, detecting the port voltage and the port current of the power supply port until the port voltage and the port current of the power supply port reach a second stable state, and obtaining a second steady-state voltage, a second steady-state current, a plurality of discharge voltage values ​​and a discharge time; The signature impedance of the powered device is acquired according to the first steady-state voltage, the first steady-state current, the second steady-state voltage, the second steady-state current, a plurality of discharge voltage values, and the discharge time.

2. The legitimacy detection method according to claim 1, characterized in that: Also includes: When the port voltage of the power supply port is greater than the threshold voltage, a third power supply signal is provided at the power supply port, the third power supply signal is a second voltage signal, and the port voltage of the power supply port is detected, wherein the second voltage signal is greater than the first voltage signal; When the port voltage of the power supply port is greater than the second preset voltage signal, the second preset voltage signal is provided at the power supply port, and the port voltage and the port current of the power supply port are detected until the port voltage and the port current of the power supply port reach a third stable state, thereby obtaining a third steady-state voltage and a third steady-state current; Providing a second current signal at the power supply port, detecting a port voltage and a port current of the power supply port to obtain a plurality of charging voltage values ​​and a charging time; The signature impedance of the powered device is acquired according to the first steady-state voltage, the first steady-state current, the third steady-state voltage and the third steady-state current, a plurality of charging voltage values, the second current signal, and the charging time.

3. The legitimacy detection method according to claim 1, characterized in that: The first current signal is half of the first steady-state current.

4. The legitimacy detection method according to claim 2, characterized in that: The second current signal is N times the third steady-state current, where N is a positive number greater than 1.

5. The legitimacy detection method according to claim 1, characterized in that: Acquiring the signature impedance of the powered device according to the first steady-state voltage, the first steady-state current, the second steady-state voltage and the second steady-state current, a plurality of discharge voltage values, the first current signal, and the discharge time includes: Acquire a signature resistance of the powered device according to the first steady-state voltage, the first steady-state current, the second steady-state voltage, and the second steady-state current; The signature capacitance of the powered device is acquired according to the multiple discharge voltage values, the first current signal, the discharge time, and the signature resistance.

6. The legitimacy detection method according to claim 2, characterized in that: Acquiring the signature impedance of the powered device according to the first steady-state voltage, the first steady-state current, the third steady-state voltage and the third steady-state current, a plurality of charging voltage values, the second current signal and the charging time comprises: Acquire a signature resistance of the powered device according to the first steady-state voltage, the first steady-state current, the third steady-state voltage, and the third steady-state current; The signature capacitance of the powered device is acquired according to the multiple charging voltage values, the second current signal, the charging time, and the signature resistance.

7. The legitimacy detection method according to claim 1, characterized in that: Also includes: Whether to supply power to the powered device is determined based on the signature impedance of the powered device.

8. The legitimacy detection method according to claim 1, characterized in that: Also includes: Determining whether the port voltage of the power supply port is less than an initial voltage signal; When the port voltage of the power supply port is less than the initial voltage signal, the initial voltage signal is provided at the power supply port until the port voltage and the port current of the power supply port reach a steady state.

9. A power supply device for an Ethernet system, wherein: The Ethernet power supply system includes a power supply device, a powered device and an interface unit connected therebetween, wherein the power supply device includes a power supply port and is characterized in that it includes: A first detection power supply, connected to the power supply port, and used to provide a voltage signal to the power supply port; A second detection power supply, connected to the power supply port, for providing a current signal to the power supply port; a controller connected to the first detection power supply, the second detection power supply and the power supply port, and configured to control the first detection power supply to provide a first power supply signal to the power supply port, wherein the first power supply signal is a first voltage signal, and detect a port voltage of the power supply port, wherein the first voltage signal is greater than a first preset voltage signal; The controller is further configured to control the first detection power supply to provide the first preset voltage signal to the power port when the port voltage of the power port is greater than the first preset voltage signal, and detect the port voltage and port current of the power port until the port voltage and port current of the power port reach a first stable state, thereby obtaining a first steady-state voltage and a first steady-state current, wherein the first stable state is a state in which the first steady-state voltage is equal to the amplitude of the first preset voltage signal; The controller is also used to control the second detection power supply to provide a second power supply signal to the power supply port, where the second power supply signal is different from the first voltage signal, and when the second power supply signal is a first current signal, detect whether the port voltage of the power supply port is less than a threshold voltage after a first preset time; The controller is also used for detecting the port voltage and the port current of the power supply port when the port voltage of the power supply port is less than the threshold voltage until the port voltage and the port current of the power supply port reach a second stable state, and obtaining a second steady-state voltage and a second steady-state current, a plurality of discharge voltage values ​​and a discharge time; The controller is further configured to obtain a signature impedance of the powered device according to the first steady-state voltage, the first steady-state current, the second steady-state voltage, the second steady-state current, a plurality of discharge voltage values, and a discharge time.

10. The power supply device according to claim 9, characterized in that: The controller comprises: A voltage detection unit, used for obtaining the port voltage of the power supply port; A current detection unit, used for obtaining the port current of the power supply port; A control unit, used to control the first detection power supply to provide a first power supply signal to the power supply port, wherein the first power supply signal is a first voltage signal, and detect the port voltage of the power supply port through the voltage detection unit, wherein the first voltage signal is greater than a first preset voltage signal; The control unit is also used to determine whether the port voltage of the power supply port is greater than a first preset voltage signal; The control unit is further used for providing a first preset voltage signal at the power port when the port voltage of the power port is greater than a first preset voltage signal, and detecting the port voltage of the power port by the voltage detection unit and detecting the port current of the power port by the current detection unit until the port voltage and the port current of the power port reach a first stable state, thereby obtaining a first steady-state voltage and a first steady-state current; The control unit is further used to control the second detection power supply to provide a second power supply signal to the power supply port, where the second power supply signal is a first current signal, and detect the port voltage of the power supply port after a first preset time through the voltage detection unit; The control unit is also used to determine whether the port voltage of the power supply port is less than a threshold voltage after a first preset time; The control unit is further configured to, when the port voltage of the power port is less than a threshold voltage, detect the port voltage of the power port through the voltage detection unit and detect the port current of the power port through the current detection unit until the port voltage and the port current of the power port reach a second stable state, thereby obtaining a second steady-state voltage and a second steady-state current, a plurality of discharge voltage values, and a discharge time; The control unit is further configured to obtain a signature impedance of the powered device according to the first steady-state voltage, the first steady-state current, the second steady-state voltage and the second steady-state current, a plurality of discharge voltage values, a first current signal and a discharge time.

11. The power supply device according to claim 10, characterized in that: The control unit is further used for, when the port voltage of the power supply port is greater than a threshold voltage, providing a third power supply signal at the power supply port, the third power supply signal being a second voltage signal, detecting the port voltage of the power supply port by the voltage detection unit, wherein the second voltage signal is greater than the first voltage signal; and when the port voltage of the power supply port is greater than a second preset voltage signal, providing a second preset voltage signal at the power supply port, detecting the port voltage of the power supply port by the voltage detection unit, and detecting the port current of the power supply port by the current detection unit until the port voltage and the port current of the power supply port reach a third stable state, thereby obtaining a third steady-state voltage and a third steady-state current; The control unit is further used to provide a second current signal at the power supply port, detect the port voltage of the power supply port through the voltage detection unit, and detect the current of the power supply port through the current detection unit to obtain multiple charging voltage values ​​and charging time; The control unit is further configured to obtain a signature impedance of the powered device according to the first steady-state voltage, the first steady-state current, the third steady-state voltage and the third steady-state current, a plurality of charging voltage values, a second current signal, and a charging time.

12. The power supply device according to any one of claims 9 to 11, characterized in that: The first current signal is half of the first steady-state current.

13. The power supply device according to claim 11, characterized in that: The second current signal is N times the third steady-state current, where N is a positive number greater than 1.

14. The power supply device according to claim 10, characterized in that: The control unit is used to obtain the signature resistance of the powered device according to the first steady-state voltage, the first steady-state current, the second steady-state voltage and the second steady-state current; and to obtain the signature capacitance of the powered device according to the multiple discharge voltage values, the first current signal, the discharge time and the signature resistance.

15. The power supply device according to claim 11, characterized in that: The control unit is used to obtain the signature resistance of the powered device according to the first steady-state voltage, the first steady-state current, the third steady-state voltage and the third steady-state current; and to obtain the signature capacitance of the powered device according to the multiple charging voltage values, the second current signal, the charging time and the signature resistance.

16. The power supply device according to claim 10 or 11, characterized in that: The control unit is further configured to determine whether to supply power to the powered device according to the signature impedance of the powered device.

17. The power supply device according to claim 10, characterized in that: The control unit is also used to determine whether the port voltage of the power supply port is less than the initial voltage signal; The control unit is also used to control the first detection power supply to provide an initial voltage signal at the power supply port until the port voltage and port current of the power supply port reach a steady state when the port voltage of the power supply port is less than the initial voltage signal.

18. A method for detecting the legitimacy of an Ethernet power supply system, wherein: The Ethernet power supply system includes a power supply device, a powered device and an interface unit connected therebetween, wherein the power supply device includes a power supply port and is characterized in that it includes: Providing a first voltage signal at the power supply port and detecting a port voltage of the power supply port, wherein the first voltage signal is greater than a first preset voltage signal; When the port voltage of the power supply port is greater than the first preset voltage signal, the first preset voltage signal is provided at the power supply port, and the port voltage and the port current of the power supply port are detected until the port voltage and the port current of the power supply port reach a first stable state, and a first steady-state voltage and a first steady-state current are obtained, wherein the first stable state is a state in which the first steady-state voltage is equal to the amplitude of the first preset voltage signal; Providing a second voltage signal at the power supply port, and detecting a port voltage of the power supply port, wherein the second voltage signal is greater than the first voltage signal; When the port voltage of the power supply port is greater than the second preset voltage signal, the second preset voltage signal is provided at the power supply port, and the port voltage and the port current of the power supply port are detected until the port voltage and the port current of the power supply port reach a third stable state, thereby obtaining a third steady-state voltage and a third steady-state current; Providing a second current signal at the power supply port, detecting a port voltage and a port current of the power supply port to obtain a plurality of charging voltage values ​​and charging times; The signature impedance of the powered device is acquired according to the first steady-state voltage, the first steady-state current, the third steady-state voltage and the third steady-state current, a plurality of charging voltage values, the second current signal, and the charging time.

19. The legitimacy detection method according to claim 18, characterized in that: Acquiring the signature impedance of the powered device according to the first steady-state voltage, the first steady-state current, the third steady-state voltage, the third steady-state current, and a plurality of charging voltage values ​​comprises: Acquire a signature resistance of the powered device according to the first steady-state voltage, the first steady-state current, the third steady-state voltage, and the third steady-state current; The signature capacitance of the powered device is acquired according to the multiple charging voltage values, the second current signal, the charging time, and the signature resistance.

20. The legitimacy detection method according to claim 18 or 19, characterized in that: Also includes: Whether to supply power to the powered device is determined based on the signature impedance of the powered device.

21. The legitimacy detection method according to claim 18, characterized in that: Also includes: Determining whether the port voltage of the power supply port is less than an initial voltage signal; When the port voltage of the power supply port is less than the initial voltage signal, the initial voltage signal is provided at the power supply port until the port voltage and the port current of the power supply port reach a steady state.

22. A power supply device for an Ethernet system, wherein: The Ethernet power supply system includes a power supply device, a powered device and an interface unit connected therebetween, wherein the power supply device includes a power supply port and is characterized in that it includes: A first detection power supply, connected to the power supply port, and used to provide a voltage signal to the power supply port; A second detection power supply, connected to the power supply port, for providing a current signal to the power supply port; a controller connected to the first detection power supply, the second detection power supply and the power supply port, and configured to control the first detection power supply to provide a first voltage signal to the power supply port, and detect a port voltage of the power supply port, wherein the first voltage signal is greater than a first preset voltage signal; The controller is further configured to control the first detection power supply to provide the first preset voltage signal to the power port when the port voltage of the power port is greater than the first preset voltage signal, and detect the port voltage and port current of the power port until the port voltage and port current of the power port reach a first stable state, thereby obtaining a first steady-state voltage and a first steady-state current, wherein the first stable state is a state in which the first steady-state voltage is equal to the amplitude of the first preset voltage signal; The controller is further used to provide a second voltage signal at the power supply port and detect the port voltage of the power supply port, wherein the second voltage signal is greater than the first voltage signal; The controller is also used for providing a second preset voltage signal at the power supply port when the port voltage of the power supply port is greater than the second preset voltage signal, and detecting the port voltage and port current of the power supply port until the port voltage and port current of the power supply port reach a third stable state, thereby obtaining a third steady-state voltage and a third steady-state current; The controller is also used to provide a second current signal at the power supply port, detect the port voltage and port current of the power supply port to obtain multiple charging voltage values ​​and charging time; The signature impedance of the powered device is acquired according to the first steady-state voltage, the first steady-state current, the third steady-state voltage and the third steady-state current, a plurality of charging voltage values, the second current signal, and the charging time.

23. The power supply device according to claim 22, characterized in that: The controller comprises: A voltage detection unit, used for obtaining the port voltage of the power supply port; A current detection unit, used for obtaining the port current of the power supply port; A control unit, used for controlling the first detection power supply to provide a first voltage signal to the power supply port, and detecting the port voltage of the power supply port through the voltage detection unit, wherein the first voltage signal is greater than a first preset voltage signal; The control unit is also used to determine whether the port voltage of the power supply port is greater than a first preset voltage signal; The control unit is further used for providing a first preset voltage signal at the power port when the port voltage of the power port is greater than a first preset voltage signal, and detecting the port voltage of the power port by the voltage detection unit and detecting the port current of the power port by the current detection unit until the port voltage and the port current of the power port reach a first stable state, thereby obtaining a first steady-state voltage and a first steady-state current; The control unit is further used to provide a second voltage signal at the power supply port, and detect the port voltage of the power supply port through the voltage detection unit, wherein the second voltage signal is greater than the first voltage signal; and when the port voltage of the power supply port is greater than the second preset voltage signal, provide a second preset voltage signal at the power supply port, detect the port voltage of the power supply port through the voltage detection unit, and detect the port current of the power supply port through the current detection unit until the port voltage and the port current of the power supply port reach a third stable state, thereby obtaining a third steady-state voltage and a third steady-state current; The control unit is further used to provide a second current signal at the power supply port, detect the port voltage of the power supply port through the voltage detection unit, and detect the current of the power supply port through the current detection unit to obtain multiple charging voltage values ​​and charging time; The control unit is further configured to obtain a signature impedance of the powered device according to the first steady-state voltage, the first steady-state current, the third steady-state voltage and the third steady-state current, a plurality of charging voltage values, a second current signal, and a charging time.

24. The power supply device according to claim 23, characterized in that: The control unit is further configured to determine whether to supply power to the powered device according to the signature impedance of the powered device.

25. The power supply device according to claim 23, characterized in that: The control unit is also used to determine whether the port voltage of the power supply port is less than the initial voltage signal; The control unit is also used to control the first detection power supply to provide an initial voltage signal at the power supply port until the port voltage and port current of the power supply port reach a steady state when the port voltage of the power supply port is less than the initial voltage signal.

Images