Power sourcing equipment, buck control circuit and control method therefor

Abstract

Power sourcing equipment, for coupling to a powered device. The power sourcing equipment comprises a power supply apparatus, an output control circuit, a path control circuit and a control module. When the output control circuit detects that a powered device is not coupled to an output end of the power sourcing equipment, the path control circuit disconnects a power supply path from the output end to the control module, and the output control circuit adjusts an output voltage to a first voltage, so that the control module enters a disabled state. When the output control circuit detects that the powered device is coupled to the output end, the path control circuit short-circuits the power supply path, and the output control circuit adjusts the output voltage to a second voltage, so that the control module enters an enabled state. The present disclosure further relates to a buck control circuit, and a control method for power sourcing equipment.

Description

An Ethernet power supply, a step-down control circuit, and a control method thereof. Technical Field

[0001] This invention relates to an Ethernet power supply, a control circuit, and a control method thereof, and particularly to an Ethernet power supply with power-saving function, a step-down control circuit, and a control method thereof. Background Technology

[0002] Power over Ethernet (PoE) is a standardized or proprietary technology that transmits power and data to devices over an Ethernet network via twisted-pair cabling. This technology primarily uses a Power Source Equipment (PSE) to couple to a power device (PD) via at least one RJ45 network cable to simultaneously transmit power and data. Therefore, this technology eliminates the need for an additional power outlet, saving time and money associated with configuring power cables.

[0003] However, most current products on the market rely on a continuous handshake signal communication between the Ethernet Power Supply (PSE) and the load device (PD) to determine whether the PSE should supply power to the correct PD. Therefore, even when the PD is not connected or has been disconnected, the PSE continues to send handshake signals for detection, resulting in continuous power loss during PSE standby. This means that current PSEs cannot meet the power consumption requirements under current energy efficiency regulations (such as, but not limited to, DoE, EC CoC, etc.) regarding no-load power consumption.

[0004] Therefore, how to design an Ethernet power supply that minimizes the power consumption of the Ethernet power supply when the load device is not connected to the Ethernet power supply is a major research topic that the inventors of this disclosure intend to study.

[0005] Summary of the Invention

[0006] To address the aforementioned problems, this disclosure provides an Ethernet power supply to overcome the limitations of existing technologies. Therefore, the Ethernet power supply of this disclosure is used to couple to a load device, and includes a power supply device, an output control circuit, a path control circuit, and a control module. The power supply device converts an input voltage into an output voltage and provides the output voltage to the load device from its output terminal. The output control circuit is coupled to the output terminal and adjusts the output voltage to a first voltage or a second voltage depending on whether the output terminal is coupled to a load device. The path control circuit is coupled to the output terminal, and the control module is coupled to the path control circuit. Specifically, when the output control circuit detects that the load device is not coupled to the output terminal, the path control circuit disconnects the power supply path from the output terminal to the control module, and adjusts the output voltage to the first voltage to disable the control module. When the output control circuit detects that the load device is coupled to the output terminal, the path control circuit short-circuits the power supply path, and adjusts the output voltage to the second voltage to enable the control module.

[0007] To address the aforementioned problems, this disclosure provides a buck control circuit to overcome the limitations of the prior art. Therefore, the buck control circuit of this disclosure is applied to an Ethernet power supply, which includes a power supply device providing an output voltage via a first terminal and a second terminal. The power supply device includes a feedback control circuit, which includes a clamping element, a feedback circuit, and a voltage regulator circuit connected in series to the second terminal of the power supply device, and a first voltage divider circuit coupled to the second terminal and the voltage regulator circuit. The buck control circuit includes a second voltage divider circuit, an impedance control circuit, and a bypass circuit, with the second voltage divider circuit connected in series to the first voltage divider circuit. The impedance control circuit is connected in parallel to the second voltage divider circuit and coupled to the first terminal to selectively bypass the second voltage divider circuit and provide a first impedance or a second impedance to the voltage regulator circuit. The bypass circuit is coupled to the first terminal and connected in parallel to the clamping element. The power supply pin of the controller of the Ethernet power supply is coupled to the impedance control circuit and the bypass circuit. When the first terminal is at the first potential, and the power supply path from the second terminal to the power supply pin is broken to provide the first path voltage to the impedance control circuit, the impedance control circuit does not bypass the second voltage divider circuit but provides the first impedance to the voltage regulator circuit, and the bypass circuit bypasses the clamping element so that the feedback circuit notifies the power supply device to reduce the output voltage to the first voltage according to the first impedance.

[0008] To address the aforementioned problems, this disclosure provides a control method for an Ethernet power supply to overcome the limitations of the prior art. Therefore, the Ethernet power supply of this disclosure receives an input voltage and is used to couple a load device. The Ethernet power supply includes a power supply device and a control module, and the control method of the Ethernet power supply includes the following steps: (a) The power supply device converts the input voltage into an output voltage and provides the output voltage to the load device from its output terminal. (b) When the Ethernet power supply detects that the load device is not coupled to the power supply device, it disconnects the power supply path from the output terminal to the control module to disable the control module. (c) Based on the load device not being coupled to the power supply device, the output voltage is adjusted to a first voltage. (d) When the Ethernet power supply detects that the load device is coupled to the power supply device, it short-circuits the power supply path to enable the control module. (e) Based on the load device being coupled to the power supply device, the output voltage is adjusted to a second voltage.

[0009] The main objective and technical effect of this disclosure is that, when the load device is not coupled to the output of the Ethernet power supply, the output control circuit controls the power supply device to adjust the output voltage to a first voltage to enter a buck power-saving mode and reduce the output voltage, thereby disabling the Ethernet controller. This achieves a significant reduction in the power consumption of the Ethernet power supply when the load device is not coupled.

[0010] To gain a deeper understanding of the techniques, means, and effects employed by this invention to achieve its intended purpose, please refer to the following detailed description and accompanying drawings. It is believed that the purpose, features, and characteristics of this invention can be understood in a thorough and specific manner from these drawings. However, the drawings are provided for reference and illustration only and are not intended to limit the scope of this invention. Attached Figure Description

[0011] Figure 1 is a circuit block diagram of the Ethernet power supply with power-saving function disclosed in this invention;

[0012] Figure 2 is a detailed circuit block diagram of the Ethernet power supply with power-saving function disclosed herein;

[0013] Figure 3A is a circuit block diagram of the first embodiment of the path control circuit and control module of this disclosure;

[0014] Figure 3B is a circuit block diagram of a second embodiment of the path control circuit and control module of this disclosure;

[0015] Figure 4 is a circuit block diagram of the output control circuit of this disclosure;

[0016] Figure 5 is a detailed circuit block diagram of the output control circuit of this disclosure;

[0017] Figure 6 is a circuit diagram of the output control circuit of this disclosure;

[0018] Figure 7 is a flowchart of the control method for the Ethernet power supply disclosed herein; and

[0019] Figure 8 is a timing diagram of the control method of the Ethernet power supply of this disclosure.

[0020] Explanation of reference numerals in the attached figures:

[0021] 100: Ethernet Power Supply

[0022] 100-1: First end

[0023] 100-2: Second end

[0024] 100-3: Output terminal

[0025] Bn: First end

[0026] Bp: Second end

[0027] 1: Power supply device

[0028] 2: Control Circuit

[0029] 20: Path control circuit

[0030] 21: Switching circuit

[0031] 222: Path Switch

[0032] 224: Drive switch

[0033] 23: Trigger element

[0034] 25: Unlocking circuit

[0035] 272: First unlock switch

[0036] 274: Second unlocking switch

[0037] 276: Energy storage element

[0038] D: Diode

[0039] 27: Energy storage circuit

[0040] 29: Drive circuit

[0041] 292: First drive switch

[0042] 294: Second drive switch

[0043] 22: Control Module

[0044] 220: Controller

[0045] VDD: Power supply pin

[0046] Ec1: First pin

[0047] Ec2: Second pin

[0048] SWc: Switch

[0049] 3: Data Conversion Module

[0050] 4: Output control circuit

[0051] 40: Voltage divider circuit

[0052] 402: First voltage divider circuit

[0053] Ra, Rb: Resistance

[0054] P: Node

[0055] 404: Second voltage divider circuit

[0056] 406: Impedance Control Circuit

[0057] SW1: Switch

[0058] 42: Voltage Regulator Circuit

[0059] 44: Feedback Circuit

[0060] 46: Clamping circuit

[0061] 462: Clamping element

[0062] 464: Bypass circuit

[0063] SW2, SW3: Switches

[0064] Rc, Rd: Resistance

[0065] 5: Feedback control circuit

[0066] 6: Step-down control circuit

[0067] 200: Load device

[0068] 300: External device

[0069] Li: Power cord

[0070] Vin: Input voltage

[0071] Vo: Output voltage

[0072] Vo1: First voltage

[0073] Vo2: Second voltage

[0074] Vu: Unlock voltage

[0075] Vl: Path voltage

[0076] Vl1: Voltage of the first path

[0077] Vl2: Second path voltage

[0078] Vz: Clamping voltage

[0079] Vr: Regulated voltage

[0080] So: external signal

[0081] Sh: Handshake signal

[0082] Sc: Control signal

[0083] Ss: Detection signal

[0084] Sf: Feedback signal

[0085] Sf1: First feedback signal

[0086] Sf2: Second feedback signal

[0087] Lp: Power supply path

[0088] Po: Jointly outputting electricity

[0089] R: Impedance

[0090] R1: First impedance

[0091] R2: Second impedance

[0092] (S100)~(S600): Steps

[0093] t0~t6: Time

[0094] L1: First potential

[0095] L2: Second potential

[0096] L: Low level

[0097] H: High level Detailed Implementation

[0098] Please refer to Figure 1, which is a circuit block diagram of the Ethernet power supply with power-saving function disclosed herein. The Ethernet power supply 100 (Power Source Equipment; PSE) is used to couple to a load device 200 (Power Device; PD), and includes a power supply device 1, a control circuit 2, a data conversion module 3, and an output control circuit 4. The control circuit 2 is coupled to the power supply device 1 and the data conversion module 3, and the power supply device 1 receives the input voltage Vin via a power line Li coupled to a first end 100-1. The power supply device 1 converts the input voltage Vin into an output voltage Vo, and the output voltage Vo can be, for example, but not limited to, 20V to 55V (depending on the specifications of the Ethernet power supply 100). The data conversion module 3 is coupled to an external device 300 (for example, but not limited to, a network camera, a central server) via a second end 100-2 to receive external signals So provided by the external device 300, and to receive the output voltage Vo provided by the power supply device 1 and the control signals provided by the control circuit 2.

[0099] Furthermore, the control circuit 2 includes a path control circuit 20 and a control module 22, with the control module 22 internally including an Ethernet network controller (PSE controller). The path control circuit 20 is coupled to a third terminal (which can be an RJ45 network terminal, hereinafter referred to as output terminal 100-3) and the control module 22. The path control circuit 20 is used to disconnect the power supply path Lp from output terminal 100-3 to the control module 22 when the load device 200 is not coupled to output terminal 100-3, and to short-circuit the power supply path Lp from output terminal 100-3 to the control module 22 when the load device 200 is coupled to output terminal 100-3. The power supply path Lp can be, for example, but not limited to, the two ends of a switch. The path control circuit 20 can short-circuit / disconnect the power supply path Lp by controlling the switch to be on / off, but this is not a limitation; many other methods, such as, but not limited to, optocouplers and mechanical braking, can also be used to achieve this. The control module 22 is coupled to the path control circuit 20. When the control module 22 receives sufficient power and enters the enabled state, the control module can communicate with the load device 200 via a handshake signal (there are multiple communication methods, so they are indicated by dashed lines) to confirm whether the load device 200 is a valid load.

[0100] On the other hand, the Ethernet power supply 100 may optionally include a data conversion module 3 to convert the signal output by the Ethernet power supply 100 into a signal format suitable for communication with the load device 200. However, if the load device 200 does not require this, the data conversion module 3 can be omitted. Specifically, the data conversion module 3 is coupled to the output terminal 100-3 to couple to the load device 200. The data conversion module 3 is used to integrate the output voltage Vo, the control signal provided by the control circuit 2, and the external signal So into a combined output power Po (including voltage, current, and signal), and to provide the combined output power Po to the device interface 200-1 of the load device 200 through the output terminal 100-3. The data conversion module 3 may include signal-to-voltage conversion units (not shown), which, in addition to integrating the output voltage Vo, the control signal provided by the control circuit 2, and the external signal So into a combined output power Po, can also convert voltage or signal into voltage or signal that meets the requirements of the load device 200.

[0101] Output control circuit 4 is coupled to output terminal 100-3 and power supply device 1, and adjusts the output voltage according to whether output terminal 100-3 is coupled to load device 200. Specifically, the main objective and technical effect of this disclosure is that, in addition to detecting whether load device 200 is connected to determine whether to operate the Ethernet controller (PSE controller) inside control circuit 2, Ethernet power supply 100 also determines whether to enter buck mode. When load device 200 is not coupled to output terminal 100-3 of Ethernet power supply 100 (i.e., load device 200 is not coupled to power supply device 1 through RJ45 network terminal), output control circuit 4 controls power supply device 1 to adjust output voltage Vo to a first voltage Vo1 (e.g., but not limited to, below 20V) to enter buck power saving mode and reduce output voltage Vo, and disable the Ethernet controller. Conversely, when the load device 200 is coupled to the output terminal 100-3 of the Ethernet power supply 100 (i.e., the load device 200 is coupled to the power supply device 1 via an RJ45 network terminal), the output control circuit 4 controls the power supply device 1 to adjust the output voltage Vo to a second voltage Vo2 (e.g., but not limited to, above 55V) to cancel the buck power saving mode and enable the Ethernet controller. After the Ethernet controller is enabled, it can communicate with the load device 200 via a handshake signal to confirm whether the load device 200 is a valid load.

[0102] Furthermore, when the Ethernet controller confirms that the load device 200 is a valid load through a handshake signal, the power supply device 1 supplies the load device 200 with the required power (e.g., but not limited to, 0.44W to 3.84W, 3.84W to 6.49W, 36W, etc., depending on the needs of the load device 200). Conversely, if the load device 200 is not a valid load, it means that the load device 200 does not comply with the specific specifications of Power over Ethernet (e.g., but not limited to the IEEE 802.3 Power over Ethernet specification). Therefore, the power supply device 1 can supply the load device 200 with default power (e.g., but not limited to, 0.44W to 12.95W). The aforementioned buck power-saving mode means that when the load device 200 is not connected, the Ethernet controller will automatically enter a disabled mode because it cannot receive power, causing it to stop operating and not consume power. Therefore, the Ethernet power supply 100 will only consume the original power required by the power supply device 1. Furthermore, since the output voltage Vo of the power supply device 1 is also reduced to the first voltage Vo1, the power consumed by the Ethernet power supply 100 can be reduced, making it easier to comply with the energy efficiency regulations (such as, but not limited to, DoE, EC CoC, MEPS, Tier, etc.) regarding power consumption under no-load conditions.

[0103] For example, taking the 36W specification of EC CoC v5 Tier 2 as an example, the power loss of Ethernet power supply 100 under no-load conditions must be less than or equal to 75mW. Assuming the power loss of Ethernet power supply 100 under no-load conditions is 65mW, and the power loss of control circuit 2, which includes the Ethernet controller, is 200mW when it is activated, the power loss of Ethernet power supply 100 without power-saving function under no-load conditions is 65mW + 200mW = 265mW, which is not less than or equal to 75mW and therefore does not comply with energy specifications. However, the power-saving Ethernet power supply 100 of this disclosure, when coupled to the no-load device 200, does not consume power because the Ethernet controller enters a disabled state, and the output voltage Vo is stepped down to a first voltage Vo1. Therefore, the power loss under no-load conditions is at most 65mW (the power loss is expected to decrease even further after the output voltage Vo is stepped down), thus complying with energy specifications.

[0104] Please refer to Figure 2 for a detailed circuit block diagram of the power-saving Ethernet power supply of this disclosure, and also refer to Figure 1. Figure 2 mainly shows the detailed circuit blocks of the power supply device 1, the control circuit 2, and the output control circuit 4, and further discloses the coupling relationship between the devices. Specifically, the output terminal 100-3 includes a negative bus terminal (hereinafter referred to as the first terminal Bn) and a positive bus terminal (hereinafter referred to as the second terminal Bp), and the power supply device 1 can provide an output voltage Vo to the load device 200 through the first terminal Bn and the second terminal Bp. The path control circuit 20 is coupled to the first terminal Bn, the second terminal Bp, and the control module 22, and the control module 22 is coupled to the first terminal Bn. The power supply device 1 can be an AC / DC converter or a DC / DC converter, and is preferably a converter with an isolation transformer (e.g., but not limited to flyback, LLC, etc. converters).

[0105] The path control circuit 20 determines whether the load device 200 is coupled to the output terminal 100-3 based on the voltage change at the first terminal Bn. When the path control circuit 20 determines that the load device 200 is not coupled to the output terminal 100-3 based on the voltage change at the first terminal Bn, the path control circuit 20 disconnects the power supply path Lp, preventing the output voltage Vo from being supplied to the control module 22 through the second terminal Bp and the power supply path Lp. Therefore, the control module 22 cannot receive the power required for operation and enters a disabled state. Conversely, when the path control circuit 20 determines that the load device 200 is coupled to the output terminal 100-3 based on the voltage change at the first terminal Bn, the path control circuit 20 short-circuits the power supply path Lp, allowing the output voltage Vo to be supplied to the control module 22 through the second terminal Bp and the power supply path Lp. Therefore, the control module 22 can receive the power required for operation and enters an enabled state.

[0106] Furthermore, the control module 22 includes an Ethernet controller (hereinafter referred to as controller 220) and a communication module (e.g., but not limited to, a switch SWc). Controller 220 includes a power supply pin VDD, a first pin Ec1, and a second pin Ec2. The power supply pin VDD is coupled to the path control circuit 20 to receive the power required for operation through the power supply path Lp and enter the enabled state. One end of the switch SWc is coupled to the first pin Ec1 and the first terminal Bn, and the other end of the switch SWc is grounded. The control terminal of the switch SWc is coupled to the second pin Ec2.

[0107] When the load device 200 is not connected to the power supply device 1, the path control circuit 20 disconnects the coupling between the power supply device 1 and the second terminal Bp, so that the controller 220 of the control circuit 2 is de-energized and enters a disabled state. At this time, the first terminal Bn is at a first potential (e.g., but not limited to, a low potential), and the controller 220 cannot control the switch SWc to turn it off. When the load device 200 is connected to the power supply device 1, a transient loop is formed between the power supply device 1, the second terminal Bp, the load device 200, and the first terminal Bn, causing the voltage of the first terminal Bn to be at a second potential (e.g., but not limited to, a high potential) corresponding to the voltage of the second terminal Bp. Therefore, the path control circuit 20 short-circuits the power supply path Lp according to the voltage of the second terminal Bp, so that the output voltage Vo can be provided to the controller 220 through the power supply path Lp, and the controller 220 can receive the power required for operation from the power supply pin VDD and enter the enabled state.

[0108] After controller 220 enters the enabled state, it provides a handshake signal Sh to the first terminal Bn via the first pin Ec1 to establish handshake communication with the load device 200. Once the handshake communication between controller 220 and load device 200 is complete, controller 220 stops providing the handshake signal Sh and provides a control signal Sc via the second pin Ec2 to turn on switch SWc, grounding the first terminal Bn. Specifically, after communication between controller 220 and load device 200 is complete, if controller 220 confirms that load device 200 is a valid load, then power supply device 1 supplies the required power to load device 200. Conversely, if controller 220 confirms that load device 200 is an invalid load, then power supply device 1 provides default power to load device 200.

[0109] When the load device 200 is disconnected from the power supply device 1, the voltage at the first terminal Bn will change to, for example, but not limited to, a second potential (for example, but not limited to, a high potential, but it could also be a low potential, depending on the actual circuit design). The controller 220, based on the voltage change at the first terminal Bn, controls the switch SWc to turn off by changing the potential of the control signal Sc via the second pin Ec2, thereby restoring the first terminal Bn to the state where the load device 200 is not connected. Furthermore, the path control circuit 20 also disconnects the power supply path Lp based on the potential change of the control signal Sc, thereby de-energizing the controller 220 and putting it into a disabled state.

[0110] It is worth mentioning that, in one embodiment, the controller 220 may also lack the handshake mechanism. If the controller 220 lacks the handshake mechanism, then the first pin Ec1 can be a detection pin for detecting specific parameters of the load device 200, and the detection result is used to determine whether the load device 200 is a valid load. Furthermore, the operation mode of lacking the handshake mechanism can be equivalently deduced from the above description, and will not be elaborated further here.

[0111] On the other hand, the output control circuit 4 is coupled to the first terminal Bn, the second terminal Bp, and the path control circuit 20. When the load device 200 is not connected to the power supply device 1, the output control circuit 4 does not receive a signal from the first terminal Bn or the path control circuit 20. Therefore, the output control circuit 4 adjusts the output voltage Vo to the first voltage Vo1 to reduce the power consumption of the Ethernet power supply 100. When the load device 200 is connected to the power supply device 1, since the voltage of the first terminal Bn corresponds to the voltage of the second terminal Bp and is at the second potential, the output control circuit 4 adjusts the output voltage Vo from the first voltage Vo1 to the second voltage Vo2 according to the first terminal Bn being at the second potential. At this time, the path control circuit 20 also short-circuits the power supply path Lp, so that the output voltage Vo can be provided to the controller 220 through the power supply path Lp, and the controller 220 can receive the power required for operation from the power supply pin VDD and enter the enabled state.

[0112] After the controller 220 and the load device 200 have completed their communication, the first terminal Bn is grounded, and the power supply path Lp remains short-circuited. Therefore, the output control circuit 4 continuously maintains the output voltage Vo at the second voltage Vo2 due to the short circuit in the power supply path Lp. When the load device 200 is disconnected from the power supply device 1, the first terminal Bn returns to the state where it is not connected to the load device 200, and the power supply path Lp is also disconnected due to the potential change of the control signal Sc. Therefore, the output control circuit 4 adjusts the output voltage Vo from the second voltage Vo2 to the first voltage Vo1 to restore the power-saving state. In one embodiment, the output control circuit 4 can adjust the output voltage Vo by controlling the power supply device 1 (e.g., but not limited to adjusting the feedback signal of the power supply device 1), or it can directly adjust the voltage of the output terminal 100-3 (e.g., by voltage division), without limitation.

[0113] Please refer to Figure 3A, which is a circuit block diagram of a first embodiment of the path control circuit and control module of this disclosure, and also refer to Figures 1 and 2. In Figure 3A, the path control circuit 20 includes a switching circuit 21, a trigger element 23, an unlocking circuit 25, and an energy storage circuit 27. One end of the switching circuit 21 is coupled to the second terminal Bp, and the other end is coupled to the power supply pin VDD through the energy storage circuit 27. The trigger element 23 is coupled to the first terminal Bn and the switching circuit 21, and the unlocking circuit 25 is coupled to the second pin Ec2, the switching circuit 21, and the trigger element 23. When the load device 200 is not connected to the power supply device 1, the trigger element 23 and the unlocking circuit 25 disconnect the power supply path Lp from the first terminal Bn, the switching circuit 21, the energy storage circuit 27 to the power supply pin VDD, so that the controller 220 is powered off and enters a disabled state. When the load device 200 is connected to the power supply device 1, a transient loop is formed between the power supply device 1 and the load device 200, connecting the second terminal Bp to the first terminal Bn. This causes the potential of the first terminal Bn to rise from the first potential to the second potential. The trigger element 23, based on the potential rise of the first terminal Bn during the transient state when the load device 200 is connected, triggers the switching circuit 21 to provide a latching short-circuit power supply path Lp, thus short-circuiting the power supply path Lp (represented by a dashed line). After the controller 220 is powered on and enters the enabled state, the controller 220 communicates with the load device 200 via a handshake signal Sh through the first pin Ec1 to determine whether the load device 200 is a valid load.

[0114] When the controller 220 successfully communicates with the load device 200 via the handshake signal Sh and determines that the load device 200 is a valid load, the controller 220 stops providing the handshake signal Sh and provides the control signal Sc through the second pin Ec2 to control the switch SWc to turn on, so as to ground the first terminal Bn and change its potential to the first potential. Furthermore, the unlocking circuit 25 establishes the unlocking voltage Vu based on the control signal Sc. When the first terminal Bn is grounded, the output voltage Vo can be provided to the load device 200 through the first terminal Bn and the second terminal Bp to supply the power required by the load device 200 (when the controller 220 determines that the load device 200 is not a valid load, its control method is similar and will not be described further here). Since the trigger element 23 provides the function of locking the short-circuit power supply path Lp after triggering the switch circuit 21, the power supply path Lp remains short-circuited even if the state of the trigger element 23 changes.

[0115] When the load device 200 is disconnected from the power supply device 1, the potential of the first terminal Bn changes from a first potential to a transient second potential. The controller 220 changes the potential of the control signal Sc according to the potential change of the first terminal Bn, thereby controlling the switch SWc to turn off, and thus restoring the first terminal Bn to its state before the load device 200 is connected. During this process, the trigger element 23 still cannot trigger the switch circuit 21 to change its state, and the unlocking circuit 25 provides an unlocking voltage Vu to the switch circuit 21 according to the potential change of the control signal Sc, enabling the switch circuit 21 to provide the function of unlocking the disconnected power supply path Lp according to the unlocking voltage Vu.

[0116] On the other hand, the circuit structure shown in Figure 3A is merely a schematic example, mainly to form a circuit with the same operating logic according to the above-described operating method, but it is not limited thereto. Therefore, any circuit, controller, or other device that can implement the above-described operating method should be included within the scope of this embodiment. Furthermore, in Figure 3A, the trigger element 23 can be a trigger switch. One end of the trigger element 23 is coupled to the second terminal Bp, and the other end is coupled to the switch circuit 21 and the unlocking circuit 25, and the control terminal of the trigger element 23 is coupled to the first terminal Bn. The trigger element 23 is used to conduct when the potential of the first terminal Bn rises from the first potential to the second potential, so as to trigger the switch circuit 21 to provide the function of providing a latching short-circuit power supply path Lp. When the trigger element 23 triggers the switch circuit 21 to provide the function of providing a latching short-circuit power supply path Lp, the switch circuit 21 cannot be triggered again regardless of whether the trigger element 23 is on or off (i.e., before the load device 200 is removed).

[0117] The switching circuit 21, for example but not limited to, can be a dual-crystal latch circuit, which mainly includes a path switch 222 and a drive switch 224. One end of the path switch 222 is coupled to the second terminal Bp, and the other end is coupled to the energy storage circuit 27. One end of the drive switch 224 is coupled to the control terminal of the path switch 222, and the control terminal of the drive switch 224 is coupled to the trigger element 23 and the unlocking circuit 25. The drive switch 224 is used to latch the path switch 222 on or unlock the path switch 222 off according to the potential of the first terminal Bn and the potential of the control signal Sc, so as to control whether the energy storage circuit 27 is electrically coupled to the second terminal Bp. When the trigger element 23 is turned on according to the potential of the first terminal Bn rising from the first potential to the second potential, the drive switch 224 is turned on according to the turn-on of the trigger element 23, so as to control the path switch 222 to latch on, so that the energy storage circuit 27 is electrically coupled to the second terminal Bp. When the unlocking circuit 25 receives, for example but not limited to, a low-potential control signal Sc, the unlocking circuit 25 pulls down the control terminal potential of the drive switch 224 by the unlocking voltage Vu, so as to unlock the off-path switch 222 by turning off the drive switch 224.

[0118] The unlocking circuit 25 includes a first unlocking switch 272, a second unlocking switch 274, and an energy storage element 276. The control terminal of the first unlocking switch 272 is coupled to the second pin Ec2. One end of the second unlocking switch 274 is coupled to the trigger element 23 and the switching circuit 21, and the control terminal of the second unlocking switch 274 is coupled to one end of the first unlocking switch 272. The energy storage element 276 can be, for example, but not limited to, a capacitor or other element with energy storage function, and the energy storage element 276 is coupled to the second pin Ec2 and the control terminal of the second unlocking switch 274. When the controller 220 communicates with the load device 200 and provides, for example, but not limited to, a high-potential control signal Sc, the first unlocking switch 272 is turned on according to the control signal Sc, so that the control signal Sc charges the energy storage element 276 through the turn-on of the first unlocking switch 272, thereby establishing an unlocking voltage Vu in the energy storage element 276. When the controller 220 provides a low-potential control signal Sc based on the disconnection of the load device 200, for example, but not limited to, the first unlocking switch 272 is turned off according to the control signal Sc. At this time, an unlocking voltage Vu is provided to the control terminal of the second unlocking switch 274, causing the second unlocking switch 274 to turn on according to the unlocking voltage Vu. When the second unlocking switch 274 is turned on, the second unlocking switch 274 pulls down the potential of the control terminal of the drive switch 224, so as to turn off the drive switch 224 by turning on the second unlocking switch 274, thereby unlocking the off-path switch 222.

[0119] The unlocking circuit 25 may include a diode D, one end of which is the anode and coupled to the second pin Ec2 and the control terminal of the first unlocking switch 272. The other end of the diode D is the cathode and coupled to the control terminal of the second unlocking switch 274. The diode D is used to prevent the unlocking voltage Vu from generating a current flow to a path other than the control terminal of the second unlocking switch 274 when released, thereby avoiding the risk of the unlocking circuit 25 failing. It is worth noting that in one embodiment of this disclosure, the above-described circuit can be implemented using a circuit composed of transistors, resistors, and capacitors, or a circuit composed of logic gates. Therefore, the above-described implementation is only a simpler and lower-cost implementation, but it is not limited to using only the above-described circuit structure. Any circuit that can achieve the above-described operation, along with a controller with a control program, should be included within the scope of this embodiment.

[0120] Please refer to Figure 3B, which is a circuit block diagram of a second embodiment of the path control circuit and control module of this disclosure, and also refer to Figures 1-3A. The difference between the path control circuit 20 in Figure 3B and that in Figure 3A is that the triggering element 23 is a unidirectional conducting element. One end of the unidirectional conducting element is coupled to the first terminal Bn, and the other end is coupled to the switching circuit 21 and the unlocking circuit 25, and the direction from one end to the other is forward. The unidirectional conducting element can be, for example, but not limited to, a diode, a thyristor, or other unidirectional conducting element. The unidirectional conducting element is forward deflected when the potential of the first terminal Bn is the second potential, so as to trigger the switching circuit 21 to provide the function of providing a latching short-circuit power supply path Lp. After the unidirectional conducting element triggers the switching circuit 21 to provide the function of providing a latching short-circuit power supply path Lp, the switching circuit 21 cannot be triggered again, regardless of whether the triggering element 23 is on or off (i.e., before the load device 200 is removed).

[0121] In addition, the path control circuit 20 also includes a drive circuit 29. The drive circuit 29 is coupled to the second pin Ec2, the switching circuit 21, the unlocking circuit 25, and the energy storage circuit 27. The drive circuit 29 provides a path voltage Vl to the unlocking circuit 25 at the node between the switching circuit 21 and the energy storage circuit 27, based on a high-level control signal Sc, thereby driving the unlocking circuit 25 to establish an unlocking voltage Vu. Generally, since the signals provided by the controller 220 are mostly low-power signals, if they are used to drive the switching element (i.e., the first unlocking switch 272) and simultaneously charge the capacitor (i.e., the energy storage element 276), there is a risk of insufficient power causing it to fail. Therefore, the drive circuit 29 can be used to introduce the path voltage Vl to more easily drive the unlocking circuit 25. The drive circuit 29 can be, for example, but not limited to, a Darlington circuit composed of the first drive switch 292 and the second drive switch 294. A strong path voltage Vl is introduced by using a Darlington circuit and a control signal Sc, so that the unlocking circuit 25 can be driven more easily.

[0122] It is worth mentioning that, in one embodiment of this disclosure, the controller 220 in FIG3B is another implementable implementation, mainly by integrating the first pin Ec1 and the second pin Ec2 of FIG3A into a single pin Ec, and the single pin Ec can integrate the functions of the first pin Ec1 and the second pin Ec2 of FIG3A. Furthermore, in one embodiment, the implementations of FIG3A-3B can be used interchangeably, and the energy storage circuit 27 shown in FIG3A-3B can be selected according to the needs of the controller 220. Moreover, the circuit structure shown in FIG3B is only an illustrative example; therefore, any circuit, controller, or other device capable of implementing the above-described operating method should be included within the scope of this embodiment.

[0123] Please refer to Figure 4, which is a circuit block diagram of the output control circuit of this disclosure, and refer to Figures 1-3B in conjunction. In Figure 4, the output control circuit 4 includes a voltage divider circuit 40 and a voltage regulator circuit 42. The voltage divider circuit 40 is coupled to a first terminal Bn and provides an impedance R according to the potential of the first terminal Bn. The voltage regulator circuit 42 is coupled to a second terminal Bp and the voltage divider circuit 40, and adjusts the output voltage Vo according to the impedance R. Specifically, the voltage divider circuit 40 can provide a first impedance R1 (e.g., but not limited to, high impedance) when the load device 200 is not coupled to the power supply device 1 and the first terminal Bn is at a first potential, and the voltage regulator circuit 42 adjusts the output voltage Vo to a first voltage Vo1 according to the first impedance R1. In addition, the voltage divider circuit 40 can provide a second impedance R2 (e.g., but not limited to, low impedance) when the load device 200 is coupled to the power supply device 1, and the voltage regulator circuit 42 adjusts the output voltage Vo to a second voltage Vo2 according to the second impedance R2. The output control circuit 4 can determine whether the load device 200 is coupled to the power supply device 1 by, for example but not limited to, the detection signal Ss provided by the detection circuit (not shown). Therefore, only the detection signal Ss is shown in FIG4.

[0124] The output control circuit 4 can directly adjust the voltage at the output terminal 100-3 to either a first voltage Vo1 or a second voltage Vo2 via the voltage regulator circuit 42. Alternatively, the output control circuit 4 can include a feedback circuit 44 to perform feedback control and adjust the voltage output by the power supply device 1. Specifically, the feedback circuit 44 can be, for example but not limited to, an optocoupler, and is coupled to the voltage regulator circuit 42. When the feedback circuit 44 is an optocoupler, it can be connected in series between the second terminal Bp and the voltage regulator circuit 42. The controller (not shown) inside the power supply device 1 can adjust its output control signal (for example, but not limited to, a pulse width modulation signal) by detecting the magnitude of the current flowing through the optocoupler, and thereby control the power supply device 1 to adjust the output voltage Vo.

[0125] Furthermore, the voltage regulator circuit 42 can adjust the feedback signal Sf of the feedback circuit 44 to a first feedback signal Sf1 according to the first impedance R1, and the controller inside the power supply device 1 adjusts the output voltage Vo to the first voltage Vo1 according to the first feedback signal Sf1. Additionally, the voltage regulator circuit 42 can also adjust the feedback signal Sf to a second feedback signal Sf2 according to the second impedance R2, and the power supply device adjusts the output voltage Vo to the second voltage Vo2 according to the second feedback voltage. On another aspect, the output control circuit 4 also includes a clamping circuit 46, which is mainly used to clamp the voltage from the second terminal Bp to the ground terminal, preventing the voltage from being too high and exceeding the withstand voltage of the voltage regulator circuit 42. In addition, the clamping circuit 46 can also adjust the current flowing through the feedback circuit 44 (optocoupler). Specifically, the clamping circuit 46 is coupled to the voltage regulator circuit 42 and the second terminal Bp, and preferably can be connected in series between the second terminal Bp and the voltage regulator circuit 42. The clamping circuit 46 provides a clamping voltage Vz according to the load device 200 coupled to the power supply device 1, so that the voltage from the second terminal Bp to the ground terminal is equal to the sum of the regulated voltage Vr of the voltage regulator circuit 42 and the clamping voltage Vz.

[0126] Therefore, when the output voltage Vo is the second voltage Vo2, the voltage is relatively high (e.g., but not limited to, above 55V), which may cause the voltage regulator circuit 42 to be damaged due to insufficient withstand voltage. Therefore, the clamping circuit 46 can provide a clamping voltage Vz to reduce the voltage drop across the voltage regulator circuit 42 (i.e., the regulated voltage Vr) to prevent the voltage regulator circuit 42 from being damaged due to insufficient withstand voltage. Conversely, when the output voltage Vo is the first voltage Vo1 (representing that the load device 200 is not coupled to the power supply device 1, and the first terminal Bn is at the first potential), the voltage is relatively low (e.g., but not limited to, below 20V), and the voltage regulator circuit 42 is sufficient to withstand the first voltage Vo1. Therefore, the clamping circuit 46 may not provide a clamping voltage Vz. On the other hand, since the provision or non-provision of the clamping voltage Vz is related to the change in the current magnitude in this path. Therefore, the magnitude of the current flowing through the feedback circuit 44 (optocoupler) can also be adjusted by whether or not the clamping voltage Vz is provided, so that the controller (not shown) inside the power supply device 1 can adjust the output voltage Vo by detecting the magnitude of the current flowing through the optocoupler.

[0127] Please refer to Figure 5 for a detailed circuit block diagram of the output control circuit of this disclosure, and refer to Figures 1-4 in conjunction. In Figure 5, the voltage divider circuit 40 includes a first voltage divider circuit 402, a second voltage divider circuit 404, and an impedance control circuit 406. The first voltage divider circuit 402 includes a plurality of resistors Ra and Rb connected in series, and a node P of the coupled voltage regulator circuit 42 is formed between two of the series-connected resistors Ra and Rb. The second voltage divider circuit 404 is connected in series with the first voltage divider circuit 402 (i.e., connected in series with resistors Ra and Rb), and the second voltage divider circuit 404 can be, for example, but not limited to, a resistor (as shown in Figure 5) or other element that can provide impedance. The impedance control circuit 406 is connected in parallel with the second voltage divider circuit 404 and coupled to a first terminal Bn, so as to selectively bypass the second voltage divider circuit 404 according to the potential of the first terminal Bn, so that the voltage divider circuit 40 provides a first impedance R1 or a second impedance R2. Specifically, the impedance control circuit 406, based on the condition that the load device 200 is not coupled to the power supply device 1 and the first terminal Bn is at the first potential without bypassing the second voltage divider circuit 404, provides the first impedance R1 by dividing the voltage between resistors Ra and Rb and the second voltage divider circuit 404 at node P. Conversely, based on the condition that the load device 200 is coupled to the power supply device 1 and bypassing the second voltage divider circuit 404, the impedance R2 at node P is provided by dividing the voltage between resistors Ra and Rb.

[0128] The voltage regulator circuit 42 can be, for example but not limited to, a three-terminal adjustable regulator (as shown in Figure 5, such as but not limited to, a TL431, etc.), and the voltage at node P changes depending on whether the impedance R is the first impedance R1 or the second impedance R2. Specifically, when the voltage at node P changes, the voltage regulator circuit 42 sets the regulated voltage Vr at its two terminals according to the magnitude of the voltage at node P. Therefore, the change in the regulated voltage Vr can cause a change in the feedback signal Sf of the feedback circuit 44 (as shown in Figure 5, represented by the input terminal of the optocoupler), thereby allowing the power supply device 1 to adjust the output voltage Vo accordingly.

[0129] The clamping circuit 46 includes a clamping element 462 and a bypass circuit 464. The clamping element 462 can be, for example, but not limited to, a Zener diode (as shown in Figure 5) or other element that generates a stable fixed voltage based on the voltage magnitude. The clamping element 462 is coupled to the voltage regulator circuit 42 and the second terminal Bp, and is used to provide the clamping voltage Vz. The bypass circuit 464 is coupled to the first terminal Bn and is connected in parallel with the clamping element 462. The bypass circuit 464 mainly bypasses the clamping element 462 when the load device 200 is not coupled to the power supply device 1 and the first terminal Bn is at the first potential, so as not to provide the clamping voltage Vz. Conversely, when the load device 200 is coupled to the power supply device 1, the bypass circuit 464 does not bypass, allowing the clamping element 462 to provide the clamping voltage Vz.

[0130] On the other hand, whether the load device 200 is coupled to the power supply device 1 can be determined by various detection methods. For example, but not limited to, the Ethernet power supply 100 can determine whether the load device 200 is coupled to the power supply device 1 through detection by the controller 220, signals provided by the load device 200, etc. Since this disclosure includes a path control circuit 20, it can determine whether the load device 200 is coupled to the power supply device 1 by the state of short circuit or open circuit in the power supply path Lp. Specifically, the path control circuit 20 is further coupled to the output control circuit 4, so that the Ethernet power supply 100 can comprehensively determine whether the load device 200 is coupled to the power supply device 1 based on the potential of the first terminal Bn and the state of short circuit or open circuit in the power supply path Lp.

[0131] Furthermore, when the power supply path Lp is open, the voltage on this path should be the first path voltage Vl1 (i.e., low voltage, see Figures 3A-3B). Conversely, when the power supply path Lp is short-circuited, since the second terminal Bp is coupled to the power supply pin VDD, the voltage on this path should be the second path voltage Vl2 (i.e., high voltage, see Figures 3A-3B). Therefore, when the first terminal Bn is at the first potential, and the path control circuit 20 provides the first path voltage Vl1 to the output control circuit 4, it means that the load device 200 is not coupled to the power supply device 1, so that the voltage divider circuit 40 provides the first impedance R1, and the clamping circuit does not provide the clamping voltage Vz.

[0132] When the first terminal Bn is at the second potential, it indicates that the load device 200 has just been connected to or disconnected from the power supply device 1. Furthermore, when the path control circuit 20 provides the second path voltage Vl2, it indicates that the power supply path Lp is short-circuited, and the control module 22 enters the enabled state. Therefore, regardless of the situation, the voltage divider circuit 40 provides the second impedance R2, and the clamping circuit provides the clamping voltage Vz. Specifically, since the Ethernet power supply 100 and the load device 200 have completed handshake communication, the first terminal Bn may be at the first potential due to grounding, but the power supply device 1 still needs to provide the second voltage Vo2. Therefore, by comprehensively judging the path voltage Vl, it is also possible to avoid incorrectly adjusting the output voltage Vo back to the first voltage Vo1 in this situation.

[0133] Referring again to Figure 5, in the case where the output control circuit 4 includes a feedback circuit 44 for feedback control, the circuits in the output control circuit 4 can be divided into a feedback control circuit 5 belonging to the power supply device 1 and a buck control circuit 6 belonging to adjusting the output voltage Vo. Specifically, in Figure 5, the feedback control circuit 5 includes a first voltage divider circuit 402, a clamping element 462, a feedback circuit 44, and a voltage regulator circuit 42, and the buck control circuit 6 includes a second voltage divider circuit 404, an impedance control circuit 406, and a bypass circuit 464. The feedback control circuit 5 is mainly used to perform feedback control when the output voltage Vo is the second voltage Vo2 and is normally supplying power to the load device 200, so as to stabilize the voltage value of the second voltage Vo2. Furthermore, when the load device 200 disconnects from the Ethernet power supply 100, the buck control circuit 6 changes the feedback control mechanism of the feedback control circuit 5 to make the power supply device 1 reduce the output voltage Vo to the first voltage Vo1 (the circuit coupling method and control method are as described above and will not be repeated here).

[0134] Specifically, when the first terminal Bn is at a first potential, and the power supply path Lp is open, providing a first path voltage Vl1 to the impedance control circuit 406, the impedance control circuit 406 does not bypass the second voltage divider circuit 404 but provides a first impedance R1 to the voltage regulator circuit 42, and the bypass circuit 464 bypasses the clamping element 462. In this way, the current flowing through the feedback circuit 44 changes due to the impedance R being adjusted to the first impedance R1, and the feedback can then notify the power supply device 1 to reduce the output voltage Vo to the first voltage Vo1. Conversely, when the first terminal Bn is at a second potential, or the power supply path Lp is short-circuited, providing a second path voltage Vl2 to the impedance control circuit 406, the impedance control circuit 406 bypasses the second voltage divider circuit 404 and provides a second impedance R2 to the voltage regulator circuit 42, and the bypass circuit 464 does not bypass the clamping element 462, causing the clamping element 462 to provide a clamping voltage Vz. In this way, the current flowing through the feedback circuit 44 can change due to the adjustment of the clamping voltage Vz and the impedance R (adjusted to the second impedance R2), and then the power supply device 1 can be notified through feedback to raise the output voltage Vo to the second voltage Vo2.

[0135] Please refer to Figure 6, which is a circuit diagram of the output control circuit of this disclosure, and also refer to Figures 1-5. Figure 6 shows the circuit architecture that can be implemented in the circuit block of Figure 5, but it is not limited thereto. Therefore, any circuit, controller, or other device that can implement the above-described operation method should be included within the scope of this embodiment. In order to avoid obscuring the main features of this disclosure, Figure 4 only shows the secondary winding and related circuits of the power supply device 1. In addition, the clamping circuit 46 may include resistors Rc and Rd. These resistors Rc and Rd mainly adjust the current flowing through the feedback circuit 44 according to whether the bypass circuit 464 is bypassed, so that it can provide a more accurate first voltage Vo1 and second voltage Vo2. The switch SW1 of the impedance control circuit 406 and the switches SW2 and SW3 of the bypass circuit are both used for bypassing, mainly providing the bypass function when switches SW1 and SW2 are turned on. Apart from this, the operation of other circuits can be described in conjunction with Figure 5, and will not be repeated here.

[0136] Please refer to Figure 7, which is a flowchart of the control method of the Ethernet power supply of this disclosure, and also refer to Figures 1-6. The control method of the Ethernet power supply 100 mainly involves the controller 220 entering a disabled state and not consuming power when the unloaded device 200 is coupled, and the output voltage Vo is stepped down to a first voltage Vo1, thereby saving power consumption and complying with energy regulations. Specifically, the control method of the Ethernet power supply 100 includes the power supply device converting the input voltage to the output voltage and providing the output voltage to the load device from the output terminal (S100). Then, when the Ethernet power supply detects that the load device is not coupled to the power supply device, it disconnects the power supply path from the output terminal to the control module to disable the control module (S200). In a preferred embodiment, the path control circuit 20 detects the voltage change at the first terminal Bn to determine whether the load device 200 is coupled to the output terminal 100-3. When the load device 200 is not coupled to the output terminal 100-3, the path control circuit 20 disconnects the power supply path Lp, so that the output voltage Vo cannot be provided to the control module 22 through the path of the second terminal Bp and the power supply path Lp, so that the control module 22 cannot receive the power required for operation and enters a disabled state (i.e., the control module 22 is disabled).

[0137] Then, based on the fact that the load device is not coupled to the power supply device, the output voltage is adjusted to the first voltage (S300). When the load device 200 is not connected to the power supply device 1, the output control circuit 4 does not receive the signal provided by the first terminal Bn or the path control circuit 20. Therefore, the output control circuit 4 adjusts the output voltage Vo to the first voltage Vo1 to reduce the power consumption of the Ethernet power supply 100. Then, when the Ethernet power supply detects that the load device is coupled to the power supply device, it short-circuits the power supply path to enable the control module (S400). In a preferred embodiment, the path control circuit 20 short-circuits the power supply path Lp according to the voltage of the second terminal Bp, so that the output voltage Vo can be provided to the controller 220 through the power supply path Lp, and the controller 220 can receive the power required for operation from the power supply pin VDD and enter the enabled state (i.e., enable the control module 22).

[0138] Then, the output voltage is adjusted to the second voltage according to the load device coupled to the power supply device (S500). When the load device 200 is connected to the power supply device 1, since the voltage of the first terminal Bn is equal to the voltage of the second terminal Bp, the output control circuit 4 adjusts the output voltage Vo from the first voltage Vo1 to the second voltage Vo2 according to the voltage of the first terminal Bn. When the control module 22 is enabled, and the controller 220 of the control module 22 confirms that the load device 200 is a valid load through the handshake signal Sh, the power supply device 1 supplies the required power to the load device 200. Conversely, if the load device 200 is not a valid load, it means that the load device 200 does not meet the specific specifications of Power over Ethernet. Therefore, the power supply device 1 can supply default power to the load device 200. It is worth mentioning that, in one embodiment, the detailed control method of the Ethernet power supply 100 can be referred to Figures 1-6, and will not be described in detail here.

[0139] Please refer to Figure 8, which is a timing diagram of the control method of the Ethernet power supply of this disclosure, and refer to Figures 1 to 7 in conjunction. During times t0 to t1, the load device 200 is not coupled to the power supply device 1. Therefore, the first terminal Bn is at the first potential L1, and the path voltage Vl is the first path voltage Vl1. At this time, the controller 220 of the control module 22 enters a disabled state, so the control signal Sc of the control switch SWc is low (L), causing the switch SWc to turn off, and the output voltage Vo at this time is the first voltage Vo1 (e.g., but not limited to, 10V). During times t1 to t2, the load device 200 is connected to the power supply device 1, so the first terminal Bn rises from the first potential L1 to the second potential L2. However, since the path control circuit 20 and the output control circuit 4 have not yet completed the internal switching, the power supply path Lp is still open, so the path voltage Vl remains the first path voltage Vl1. Since the output voltage Vo is still the first voltage Vo1 at this time, the second potential L2 is also approximately the first voltage Vo1.

[0140] During times t2 to t3, since the path control circuit 20 and the output control circuit 4 have completed the internal switching, the power supply path Lp is short-circuited, causing the path voltage Vl to be the second path voltage Vl2. At this time, the controller 220 of the control module 22 enters the enabled state, but since it has not yet established communication with the load device 200, the control signal Sc of the control switch SWc remains at a low level L, thus keeping the switch SWc off. Furthermore, the output control circuit 4 controls the power supply device 1 to adjust the output voltage Vo to the second voltage Vo2 (e.g., but not limited to, 56V), so the second potential L2 is also approximately the second voltage Vo2. During times t3 to t4, since the load device 200 is coupled to the power supply device 1, and the output voltage Vo has been adjusted to the second voltage Vo2, and the controller 220 is powered normally, the controller 220 provides a handshake signal Sh through the first terminal Bn to establish communication with the load device 200. In one embodiment, the handshake signal Sh can be attached to the second voltage Vo2 in the form of a carrier wave, as shown in FIG8, to handshake communication with the load device 200, but is not limited thereto. It can, for example, but not limited to, handshake communication with the load device 200 through additional communication lines.

[0141] During times t4 to t5, the controller 220 has completed communication with the load device 200. Therefore, the controller 220 adjusts the control signal Sc of the control switch SWc to a high level H to turn on the switch SWc. Thus, the first terminal Bn is grounded through the conduction of the switch SWc, restoring its potential from the second potential L2 to the first potential L1. During times t5 to t6, the load device 200 disconnects from the power supply device 1. At this time, the controller 220 adjusts the control signal Sc of the control switch SWc to a low level L, and the path control circuit 20 disconnects the power supply path Lp, causing the path voltage Vl provided by the path control circuit 20 to change from the second path voltage Vl2 to the first path voltage Vl1, and restoring the controller 220 to the disabled state. Furthermore, the first terminal Bn remains at the first potential L1 due to the disconnection of the load device 200. Therefore, the output control circuit 4 controls the power supply device 1 to adjust the output voltage Vo from the second voltage Vo2 to the first voltage Vo1 based on the first path voltage Vl1 and the first potential L1 of the first terminal Bn, thereby restoring the power-saving state. It is worth mentioning that, in one embodiment, the timing diagrams of the various circuits generated by the detailed control method of the Ethernet power supply 100 can be deduced by referring to Figures 1 to 6, and will not be described in detail here.

[0142] The above description is merely a detailed explanation and accompanying drawings of preferred embodiments of the present invention, and the features of the present invention are not limited thereto, nor are they intended to limit the present invention. The scope of the present invention should be determined by the scope of the patent application. All embodiments that conform to the concept of the claims of the present invention and similar variations thereof should be included in the scope of the present invention. Any variations or modifications that can be easily conceived by those skilled in the art within the field of the present invention can be covered by the following patent scope disclosure.

Claims

1. An Ethernet power supply for coupling to a load device, wherein the Ethernet power supply comprises: A power supply device for converting an input voltage into an output voltage and providing the output voltage to the load device via an output terminal; An output control circuit is coupled to the output terminal and adjusts the output voltage to a first voltage or a second voltage depending on whether the output terminal is coupled to the load device. A path control circuit is coupled to this output terminal; and A control module, coupled to the path control circuit; Specifically, when the output control circuit detects that the load device is not coupled to the output terminal, the path control circuit disconnects a power supply path from the output terminal to the control module, and the output control circuit adjusts the output voltage to the first voltage to enable the control module to enter a disabled state; when the output control circuit detects that the load device is coupled to the output terminal, the path control circuit short-circuits the power supply path, and the output control circuit adjusts the output voltage to the second voltage to enable the control module to enter the enabled state.

2. The Ethernet power supply as claimed in claim 1, wherein the output control circuit comprises: A voltage divider circuit is coupled to a first terminal of the output terminal and provides an impedance based on the potential of the first terminal. and A voltage regulator circuit is coupled to a second terminal of the output terminal and the voltage divider circuit, and the output voltage is adjusted according to the impedance. The voltage divider circuit provides a first impedance based on the fact that the load device is not coupled to the power supply device and the first terminal is at a first potential, and the voltage regulator circuit adjusts the output voltage to the first voltage based on the first impedance; the voltage divider circuit provides a second impedance based on the fact that the load device is coupled to the power supply device, and the voltage regulator circuit adjusts the output voltage to the second voltage based on the second impedance.

3. The Ethernet power supply as claimed in claim 2, wherein the voltage divider circuit comprises: A first voltage divider circuit includes a plurality of resistors coupled in series, and a node is formed between two of the series-coupled resistors to couple the voltage regulator circuit. A second voltage divider circuit is connected in series with the resistors; and An impedance control circuit is connected in parallel with the second voltage divider circuit, and the second voltage divider circuit is selectively bypassed so that the voltage divider circuit provides the first impedance or the second impedance; The impedance control circuit provides the first impedance by not bypassing the second voltage divider circuit when the load device is not coupled to the power supply device and the first terminal is at the first potential; the impedance control circuit provides the second impedance by bypassing the second voltage divider circuit when the load device is coupled to the power supply device.

4. The Ethernet power supply as claimed in claim 2, wherein the output control circuit further comprises: A feedback circuit is coupled to the voltage regulator circuit; The voltage regulator circuit adjusts a feedback signal of the feedback circuit to a first feedback signal based on the first impedance, and the power supply device adjusts the output voltage to the first voltage based on the first feedback signal; the voltage regulator circuit... The feedback signal is adjusted to a second feedback signal according to the second impedance, and the power supply device adjusts the output voltage to the second voltage according to the second feedback signal.

5. The Ethernet power supply as claimed in claim 2, wherein the output control circuit further comprises: A clamping circuit is coupled to the voltage regulator circuit and the second terminal; The clamping circuit provides a clamping voltage based on the load device being coupled to the power supply device, such that the voltage from the second terminal to a ground terminal is equal to the sum of a regulated voltage of the voltage regulator circuit and the clamping voltage.

6. The Ethernet power supply of claim 5, wherein the clamping circuit comprises: A clamping element is coupled to the voltage regulator circuit and the second terminal, and is used to provide the clamping voltage; and A bypass circuit is connected in parallel with the clamping element; The bypass circuit bypasses the clamping element so as not to provide the clamping voltage because the load device is not coupled to the power supply device and the first terminal is at the first potential.

7. The Ethernet power supply of claim 2, wherein the path control circuit is further coupled to the output control circuit, and the voltage divider circuit provides the first impedance when the first terminal is at the first potential and the path control circuit provides a first path voltage to the output control circuit.

8. The Ethernet power supply of claim 7, wherein the voltage divider circuit provides the second impedance when the first terminal is a second potential or when the path control circuit provides a second path voltage to the output control circuit.

9. A buck control circuit applied to an Ethernet power supply, the Ethernet power supply including a power supply device providing an output voltage via a first terminal and a second terminal, and the power supply device including a feedback control circuit; the feedback control circuit including a clamping element series-coupled to a second terminal of the power supply device, a feedback circuit and a voltage regulator circuit, and a first voltage divider circuit coupled to the second terminal and the voltage regulator circuit, the buck control circuit including: A second voltage divider circuit is connected in series with the first voltage divider circuit; An impedance control circuit is connected in parallel with the second voltage divider circuit and coupled to the first terminal to selectively bypass the second voltage divider circuit and provide a first impedance or a second impedance to the voltage regulator circuit. and A bypass circuit is coupled to the first terminal and connected in parallel to the clamping element; In this case, a power pin of a controller of the Ethernet power supply is coupled to the impedance control circuit and the bypass circuit; When the first terminal is at a first potential, and a power supply path from the second terminal to the power supply pin is broken to provide a first path voltage to the impedance control circuit, the impedance control circuit does not bypass the second voltage divider circuit but provides the first impedance to the voltage regulator circuit, and the bypass circuit bypasses the clamping element so that the feedback circuit notifies the power supply device to reduce the output voltage to a first voltage according to the first impedance.

10. The step-down control circuit of claim 9, wherein when the first terminal is a second potential, or when the power supply path is short-circuited and provides a second path voltage to the impedance control circuit, the impedance control circuit bypasses the second voltage divider circuit and provides the second impedance to the voltage regulator circuit, and the bypass circuit does not bypass the clamping element and provides a clamping voltage, so that the feedback circuit notifies the power supply device to adjust the output voltage to a second voltage according to the first impedance and the clamping voltage.

11. A control method for an Ethernet power supply, the Ethernet power supply receiving an input voltage and used to couple to a load device; the Ethernet power supply includes a power supply device and a control module, and the control method for the Ethernet power supply includes the following steps: The power supply device converts the input voltage into an output voltage, and provides the output voltage to the load device through an output terminal; When the Ethernet power supply detects that the load device is not coupled to the power supply device, it disconnects a power supply path from the output terminal to the control module to disable the control module; Since the load device is not coupled to the power supply device, adjust the output voltage to a first voltage; When the Ethernet power supply detects that the load device is coupled to the power supply device, it short-circuits the power supply path to enable the control module; The output voltage is adjusted to a second voltage based on the load device coupled to the power supply device.

12. The control method of claim 11, wherein the output terminal includes a first terminal and a second terminal, and the control method further includes the following steps: An impedance is provided based on the potential of the first terminal; A first impedance is provided based on the fact that the load device is not coupled to the power supply device and the first terminal is at a first potential; The output voltage is adjusted to the first voltage based on the first impedance. A second impedance is provided based on the load device being coupled to the power supply device; and The output voltage is adjusted to the second voltage based on the second impedance.

13. The control method of claim 12, wherein the first impedance and the second impedance are provided by a first voltage divider circuit and a second voltage divider circuit, and the control method further comprises the following steps: Based on the fact that the load device is not coupled to the power supply device, and the first terminal is at the first potential without bypassing the second voltage divider circuit, the first impedance formed by the first voltage divider circuit and the second voltage divider circuit is provided; and The second voltage divider circuit is bypassed based on the load device being coupled to the power supply device, so as to provide the second impedance formed by the first voltage divider circuit.

14. The control method of claim 13, further comprising the following steps: A first feedback signal is provided based on the first impedance; The power supply device adjusts the output voltage to the first voltage according to the first feedback signal; The feedback signal is adjusted to a second feedback signal based on the second impedance; and The power supply device adjusts the output voltage to the second voltage according to the second feedback signal.

15. The control method of claim 12, further comprising the following steps: A clamping voltage is provided based on the load device coupled to the power supply device, such that the voltage from the second terminal to a ground terminal is equal to the sum of the clamping voltage and a regulated voltage; and The load device is not coupled to the power supply device, and the first terminal is at the first potential and does not provide the clamping voltage.

16. The control method of claim 12, further comprising the following steps: When the first terminal is at the first potential and the power supply path is disconnected according to a first path voltage, the first impedance is provided; and The second impedance is provided when the first terminal is at a second potential, or when the power supply path is short-circuited according to a second path voltage.

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