A power supply circuit and network device

Abstract

Embodiments of the present application provide a power supply circuit and network equipment to solve the problem that the line is complex and occupies a large PCB space when power is supplied to a PD device unit in the prior art. In the embodiments of the present application, the PD control unit of the power supply circuit detects the target power value output by the connected power supply end and outputs information of the target duty cycle corresponding to the target power value, and the PD device unit determines the corresponding operating power value according to the information of the target duty cycle, so that the PD device unit can operate according to the corresponding operating power value. Since the PD control unit sends the information of the target duty cycle to the PD device unit, the information of the target duty cycle can be sent to the PD device unit through only one pin of the PD control unit, so the line of the embodiments of the present application is not complex and occupies less space.

Description

Technical Field

[0001] This application relates to the field of circuit technology, and in particular to a power supply circuit and network device. Background Technology

[0002] Power Over Ethernet (PoE) technology refers to a technology that provides DC power to Internet Protocol (IP)-based devices while transmitting data, without altering the existing Cat.5 Ethernet cabling infrastructure. PoE technology ensures the security of existing structured cabling while maintaining the normal operation of the existing network, minimizing costs. A complete PoE system includes Power Sourcing Equipment (PSE) units and Powered Device (PD) units, with the PSE unit referred to as the power supplier. However, with the widespread adoption of WiFi 6 and above, the speed requirements for Advanced Placement (AP) devices (PD units) have increased, as have the power consumption requirements for AP devices. Traditional power suppliers cannot provide sufficient power to drive high-power PD units.

[0003] To power high-power PD devices, existing technologies employ dual-port Authenticated Transfer (AT) to supply power. However, the power supplied to the high-power PD device is typically not the maximum power of the AT. Therefore, to ensure the high-power PD device operates according to the specified power supply, existing technologies adjust the integrated circuit connected to the power supply terminal based on the power supply capacity. The output of a chip (IC) pins indicates the output power value through different voltage levels. However, IC pins can only output high and low voltage levels, and the voltage level of a single pin cannot reflect the power supply. To reflect the power supply, multiple pins of the IC chip are usually required. In practical applications, in order to send the voltage levels of multiple pins of the IC chip to the high-power PD device unit, each pin of the IC chip needs to be connected to a status feedback optocoupler. The status feedback optocoupler outputs the corresponding voltage level to the high-power PD device unit. Due to the presence of multiple status feedback optocouplers, the circuit becomes complex, resulting in a larger space occupied on the printed circuit board (PCB). Summary of the Invention

[0004] This application provides a power supply circuit and network device to solve the problem that the existing technology requires a large amount of PCB space due to the complex circuitry when powering PD device units.

[0005] In a first aspect, embodiments of this application provide a power supply circuit, which includes: a powered device (PD) control unit and a PD device unit;

[0006] The PD control unit is connected to the PD device unit and is used to detect the target power value output by the connected power supply terminal, determine the target duty cycle corresponding to the target power value according to the pre-stored correspondence between power value and duty cycle, and send the target duty cycle information to the PD device unit.

[0007] The PD device unit is used to determine the corresponding operating power value based on the target duty cycle information.

[0008] Furthermore, the PD control unit includes: a logic chip and a first field-effect transistor (MOSFET).

[0009] The first pin of the logic chip of the PD control unit is connected to the power supply terminal; the second pin of the logic chip of the PD control unit is connected to the gate of the first MOS transistor of the PD control unit.

[0010] The drain of the first MOS transistor in the PD control unit is connected to the PD device unit;

[0011] The logic chip of the PD control unit is used to detect the target power value output by the connected power supply terminal, determine the target duty cycle corresponding to the target power value according to the pre-stored correspondence between the power value and the duty cycle, and control the first MOS transistor of the PD control unit to turn on according to the target duty cycle.

[0012] Furthermore, the power supply circuit also includes: a status feedback module;

[0013] One end of the status feedback module is connected to the PD control unit, and the other end is connected to the PD device unit. It is used to receive the target duty cycle information sent by the PD control unit and send the target duty cycle information to the PD device unit.

[0014] Furthermore, the state feedback module is a state feedback optocoupler;

[0015] One end of the status feedback optocoupler is connected to the drain of the first MOS transistor of the PD control unit, and the other end of the status feedback optocoupler is connected to the PD device unit, for sending the target duty cycle information to the PD device unit.

[0016] Furthermore, the power supply circuit further includes: graded resistors; the PD control unit further includes: an operational amplifier and a second MOSFET;

[0017] One end of the graded resistor is connected to the source of the second MOS transistor of the PD control unit, and the other end of the graded resistor is connected to the source of the first MOS transistor of the PD control unit.

[0018] The gate of the second MOS transistor of the PD control unit is connected to the output terminal of the operational amplifier of the PD control unit, and the drain of the second MOS transistor of the PD control unit is left floating.

[0019] The power supply terminal of the operational amplifier of the PD control unit is connected to the third pin of the logic chip of the PD control unit, the inverting input terminal of the operational amplifier of the PD control unit is connected to the fourth pin of the logic chip of the PD control unit, and the non-inverting input terminal of the operational amplifier of the PD control unit is left floating.

[0020] The logic chip of the PD control unit is used to control the operational amplifier of the PD control unit to turn on, so as to turn on the second MOS transistor of the PD control unit; to obtain the current flowing through the graded resistor, to determine the current level corresponding to the current, and to determine the target power value of the power supply terminal according to the type of the power supply terminal and the current level; wherein, the type of the power supply terminal includes: AT type, BT type, alternative type and non-standard BT type.

[0021] Furthermore, the power supply circuit also includes: a delay unit;

[0022] The delay unit is connected to the PD control unit and is used to extend the startup time of the PD control unit.

[0023] Furthermore, the PD control unit also includes a charge pump and a third MOSFET; the delay unit includes a first capacitor and a resistor; and the power supply circuit also includes a second capacitor.

[0024] One end of the charge pump of the PD control unit is connected to the fifth pin of the logic chip of the PD control unit, and the other end is connected to the gate of the third MOS transistor of the PD control unit.

[0025] One end of the first capacitor is connected to one end of the resistor, and the other end of the resistor is connected to the gate of the third MOS transistor of the PD control unit;

[0026] The source of the third MOS transistor in the PD control unit is connected to one end of the second capacitor;

[0027] The other end of the second capacitor is connected to the source of the first MOS transistor of the PD control unit.

[0028] Furthermore, the power supply circuit also includes: a rectifier module;

[0029] One end of the rectifier module is connected to the PD control unit, and the other end is connected to the PD device unit, for adjusting the current.

[0030] Furthermore, the rectifier module includes: a first diode and a second diode;

[0031] The positive terminal of the first diode is connected to the source of the third MOS transistor of the PD control unit, and the negative terminal of the first diode is connected to the PD device unit.

[0032] The positive terminal of the second diode is grounded, and the negative terminal of the second diode is connected to the source of the first MOS transistor of the PD control unit.

[0033] Furthermore, the power supply circuit also includes: a flyback power supply module;

[0034] One end of the flyback power module is connected to the PD control unit, and the other end is connected to the PD device unit, which is used to reduce the voltage flowing through itself.

[0035] Furthermore, the power supply circuit also includes: a voltage regulation loop module;

[0036] One end of the voltage regulator loop module is connected to one end of the flyback power supply module connected to the PD control unit, and the other end is connected to one end of the flyback power supply module connected to the PD device unit, for controlling the flyback power supply module to turn on.

[0037] Furthermore, the flyback power supply module is a flyback transformer; the voltage regulation loop module includes: a control chip, a third diode, and a fourth MOSFET;

[0038] The positive terminal of the third diode is connected to the sixth pin of the logic chip of the PD control unit, and the negative terminal of the third diode is connected to the first control pin of the control chip.

[0039] The second control pin of the control chip is connected to the gate of the fourth MOS transistor;

[0040] The drain of the fourth MOS transistor is connected to the first transformer pin of the flyback transformer, and the source of the fourth MOS transistor is grounded.

[0041] The second transformer pin of the flyback transformer is connected to the negative terminal of the first diode, and the third and fourth transformer pins of the flyback transformer are connected to the PD device unit.

[0042] The logic chip of the PD control unit is used to send an enable signal to the control chip when sending the target duty cycle information;

[0043] The control chip is used to control the fourth MOSFET to turn on, so that the flyback transformer can be turned on.

[0044] Secondly, embodiments of this application also provide a network device, characterized in that the network device includes any of the power supply circuits described above.

[0045] In this embodiment, the power supply circuit includes a PD control unit and a PD device unit. The PD control unit is connected to the PD device unit. The PD control unit detects the target power value output from the connected power supply terminal, determines the target duty cycle corresponding to the target power value based on a pre-stored correspondence between power values ​​and duty cycles, and sends the target duty cycle information to the PD device unit. The PD device unit determines the corresponding operating power value based on the received target duty cycle information and operates according to the corresponding operating power value. In this embodiment, the PD control unit of the power supply circuit detects the target power value output from the connected power supply terminal and outputs the target duty cycle information corresponding to that target power value. The PD device unit determines the corresponding operating power value based on the target duty cycle information, thus enabling the PD device unit to operate according to the corresponding operating power value. Since the PD control unit only needs to send the target duty cycle information to the PD device unit through one pin, the circuitry in this embodiment is not complex and occupies less space. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 This is a schematic diagram of a power supply circuit structure provided in an embodiment of this application;

[0048] Figure 2 This is a schematic diagram of the internal structure of a PD control unit provided in an embodiment of this application;

[0049] Figure 3 A detailed structural diagram of a power supply circuit provided in an embodiment of this application;

[0050] Figure 4 This is a schematic diagram of the connection structure of a flyback transformer provided in an embodiment of this application;

[0051] Figure 5 A schematic diagram of the network port socket and network port transformer provided in the embodiments of this application;

[0052] Figure 6 A schematic diagram of the connection structure of an alternative power supply terminal provided in an embodiment of this application;

[0053] Figure 7 A complete schematic diagram of a PD control unit and connected devices provided in this application embodiment;

[0054] Figure 8 This is a schematic diagram illustrating the process by which a PD device unit determines its operating power when the power supply is operating at its maximum power, as provided in an embodiment of this application. Detailed Implementation

[0055] The present application will now be described in further detail with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present application.

[0056] In this embodiment of the application, the power supply circuit includes a PD control unit and a PD device unit. The PD control unit is connected to the PD device unit. The PD control unit is used to detect the target power value output by the connected power supply terminal, determine the target duty cycle corresponding to the target power value according to the pre-stored correspondence between the power value and the duty cycle, and send the target duty cycle information to the PD device unit. The PD device unit determines the corresponding operating power value according to the received target duty cycle information and operates according to the corresponding operating power value.

[0057] To reduce circuit complexity and space requirements, an embodiment of this application proposes a circuit.

[0058] Example 1:

[0059] Figure 1 This application provides a schematic diagram of a power supply circuit structure, which includes a PD control unit 101 and a PD device unit 102.

[0060] The PD control unit 101 is connected to the PD device unit 102 and is used to detect the target power value output by the connected power supply terminal, determine the target duty cycle corresponding to the target power value according to the pre-stored correspondence between power value and duty cycle, and send the target duty cycle information to the PD device unit 102.

[0061] The PD device unit 102 is used to determine the corresponding operating power value based on the target duty cycle information.

[0062] In this embodiment, to power the PD device unit, the power supply circuit includes a PD control unit and a PD device unit. The PD control unit is connected to the power supply terminal and also to the PD device unit, with the power supply terminal providing power to the PD device unit for operation. The power supply terminal includes Authenticated Transfer (AT) type power supply terminals, Bit Torrent (BT) type power supply terminals, alternative power supply terminals, and non-standard BT type power supply terminals. The AT type power supply terminal conforms to the IEEE 802.3at protocol, and the BT type power supply terminal conforms to the IEEE 802.3bt protocol.

[0063] In this embodiment, the PD control unit is used to detect the target power value output by the power supply terminal, i.e., the power supply power of the power supply terminal. The PD control unit can obtain the maximum power supply value of the power supply terminal and determine the target power value output by the power supply terminal based on this maximum power supply value and the detected current. How to determine the target power value based on the maximum power supply value and current is existing technology and will not be elaborated here. In this embodiment, some power supply terminals can only output their own maximum power supply value. In this case, the maximum power supply value can be determined as the target power value. For example, when the power supply terminal is a non-standard BT type power supply terminal, it can only output its own maximum power supply value, and the target power value output by the power supply terminal is 50W. In this embodiment, different types of power supply terminals may be connected to the PD control unit with different pins, allowing the PD control unit to determine the type of power supply terminal.

[0064] In this embodiment, the PD control unit can pre-store the correspondence between power values ​​and duty cycles. After detecting the target power value output from the power supply terminal, the PD control unit can determine the duty cycle corresponding to the target power value as the target duty cycle based on the pre-stored correspondence between power values ​​and duty cycles, and send the target duty cycle information to the PD device unit. Specifically, this can be achieved by first outputting a high level for a first preset duration corresponding to the target duty cycle, and then outputting a low level for a second preset duration corresponding to the target duty cycle, thereby outputting the target duty cycle information.

[0065] After receiving the target duty cycle information, the PD device unit can determine the corresponding operating power value based on the pre-saved correspondence between duty cycles and operating power values, and operate according to that operating power value. The operating power value determined by the PD device unit may differ from the target power value output by the power supply. For example, if the target power value output by the alternative power supply is sufficiently large and exceeds the PD device unit's maximum operating power value, then the PD device unit can operate at its maximum operating power value; that is, the PD device unit can operate at its full power.

[0066] In this embodiment, the power supply terminal is of type AT, meaning its maximum output power is 25W. To enable the PD device unit to operate at high power, two or more AT-type power supplies can be used. To inform the PD device unit of the power output values ​​of the two AT-type power supplies, each AT-type power supply terminal can be connected to a corresponding PD control unit, and each PD control unit sends information about its corresponding duty cycle. The PD device unit receives the duty cycle information through each interface, determines the power output value of each AT-type power supply terminal, and thus determines the operating power value based on the power output value of each AT-type power supply terminal. Alternatively, the sum of the determined power values ​​can be used as the operating power value. For example, if the PD device unit is powered by two AT-type power supplies, and both output power values ​​are 25W, then the determined operating power value is 50W.

[0067] In this embodiment, the PD control unit of the power supply circuit detects the target power value output by the connected power supply terminal and outputs the target duty cycle information corresponding to the target power value. The PD device unit determines the corresponding operating power value based on the target duty cycle information, so that the PD device unit can operate according to the corresponding operating power value. Since the PD control unit only needs to send the target duty cycle information to the PD device unit through one pin of the PD control unit, the circuit of this embodiment is not complicated and occupies less space.

[0068] Example 2:

[0069] Figure 2 This is a schematic diagram of the internal structure of a PD control unit provided in an embodiment of this application.

[0070] In order to accurately output the target duty cycle information, based on the above embodiments, in this embodiment of the application, the PD control unit includes a logic chip 201 and a first MOS transistor 202;

[0071] The first pin of the logic chip 201 of the PD control unit is connected to the power supply terminal; the second pin of the logic chip 201 of the PD control unit is connected to the gate of the first MOS transistor 202 of the PD control unit.

[0072] The drain of the first MOS transistor 202 of the PD control unit is connected to the PD device unit;

[0073] The logic chip 202 of the PD control unit is used to detect the target power value output by the connected power supply terminal, determine the target duty cycle corresponding to the target power value according to the pre-stored correspondence between the power value and the duty cycle, and control the first MOS transistor 202 of the PD control unit to be turned on according to the target duty cycle.

[0074] In this embodiment of the application, in order to output the target duty cycle information, the PD control unit of the power supply circuit further includes a logic chip and a first MOS transistor, wherein the first pin of the logic chip of the PD control unit is connected to the power supply terminal, and the second pin of the logic chip of the PD control unit is connected to the gate of the first MOS transistor of the PD control unit.

[0075] In this embodiment, the logic chip of the PD control unit is used to detect the target power value output by the power supply terminal. The logic chip can determine the target power value based on the type of the power supply terminal. Specifically, the power supply terminal includes those that supply power at maximum power and those that do not supply power at maximum power. If the power supply terminal supplies power at maximum power, the logic chip can determine the stored power value for that power supply terminal as the target power value output by that power supply terminal. For example, the target power value output by a non-standard BT type power supply terminal is 50W. If the power supply terminal of this type does not supply power at maximum power, the logic chip can determine the current flowing through the logic chip, and based on the current and the maximum power value of that type of power supply terminal, determine the target power value output by that power supply terminal. The method by which the logic chip determines the type of power supply terminal can be that different types of power supply terminals are connected to the logic chip via different pins, thus allowing the logic chip to determine the type of power supply terminal.

[0076] In this embodiment, the logic chip can pre-store the correspondence between power values ​​and duty cycles. After detecting the target power value output from the power supply terminal, the logic chip can determine the duty cycle corresponding to the target power value as the target duty cycle based on the pre-stored correspondence. After determining the target duty cycle, the logic chip can control the first MOSFET to turn on, thereby causing the first MOSFET to output the target duty cycle information. Specifically, the first MOSFET can be controlled to turn on for a first preset duration corresponding to the target duty cycle, and then controlled to turn off for a second preset duration corresponding to the target duty cycle, thereby outputting the target duty cycle information through the first MOSFET.

[0077] Example 3:

[0078] In order to accurately send the target duty cycle information to the PD device unit, based on the above embodiments, in this embodiment of the application, the power supply circuit further includes: a status feedback module;

[0079] One end of the status feedback module is connected to the PD control unit, and the other end is connected to the PD device unit. It is used to receive the target duty cycle information sent by the PD control unit and send the target duty cycle information to the PD device unit.

[0080] In this embodiment, to send the target duty cycle information to the PD device unit, the power supply circuit further includes a status feedback module. One end of the status feedback module is connected to the PD control unit, and the other end is connected to the PD device unit. In this embodiment, the PD control unit can send the target duty cycle information to the status feedback module, and the status feedback module receives the target duty cycle information sent by the PD control unit and sends the target duty cycle information to the PD device unit.

[0081] In order to accurately send the target duty cycle information to the PD device unit, based on the above embodiments, in this embodiment of the application, the status feedback module is a status feedback optocoupler;

[0082] One end of the status feedback optocoupler is connected to the drain of the first MOS transistor of the PD control unit, and the other end of the status feedback optocoupler is connected to the PD device unit, for sending the target duty cycle information to the PD device unit.

[0083] In this embodiment, to send the target duty cycle information to the PD device unit, the status feedback module can be a status feedback optocoupler. One end of the status feedback optocoupler is connected to the drain of the first MOSFET of the PD control unit, and the other end of the status feedback optocoupler is connected to the PD device unit. The pin connecting the status feedback optocoupler to the PD device unit can be pin 2 of the status feedback optocoupler, and the pin connecting the status feedback optocoupler to the PD device unit is different from the pin connecting the status feedback optocoupler to the first MOSFET.

[0084] In this embodiment, the PD control unit can send the target duty cycle information to the status feedback optocoupler through the first MOS transistor. The status feedback optocoupler receives the target duty cycle information sent by the PD control unit and sends the target duty cycle information to the PD device unit so that the PD device unit operates according to the operating power value corresponding to the target duty cycle.

[0085] The power supply circuit of this embodiment is relatively simple. It can provide power to the PD device unit through the alternative power supply terminal, BT type power supply terminal, AT type power supply terminal or non-standard BT type power supply terminal, and output a signal with the corresponding duty cycle through the PD control unit so that the PD device unit can operate according to the corresponding operating power and ensure that the PD device unit can operate normally.

[0086] Example 4:

[0087] To accurately determine the target power output value at the power supply terminal, based on the above embodiments, in this embodiment, the power supply circuit further includes: graded resistors; the PD control unit further includes: an operational amplifier 203 and a second MOSFET 204; see details below. Figure 2 :

[0088] One end of the graded resistor is connected to the source of the second MOS transistor 204 of the PD control unit, and the other end of the graded resistor is connected to the source of the first MOS transistor 202 of the PD control unit.

[0089] The gate of the second MOS transistor 204 of the PD control unit is connected to the output terminal of the operational amplifier 203 of the PD control unit, and the drain of the second MOS transistor 204 of the PD control unit is floating.

[0090] The power supply terminal of the operational amplifier 203 of the PD control unit is connected to the third pin of the logic chip 201 of the PD control unit, the inverting input terminal of the operational amplifier 203 of the PD control unit is connected to the fourth pin of the logic chip 201 of the PD control unit, and the non-inverting input terminal of the operational amplifier 203 of the PD control unit is left floating.

[0091] The logic chip 201 of the PD control unit is used to control the operational amplifier 203 of the PD control unit to turn on, so that the second MOS transistor 204 of the PD control unit is turned on; to obtain the current flowing through the graded resistor, to determine the current level corresponding to the current, and to determine the target power value of the power supply terminal according to the type of the power supply terminal and the current level; wherein, the power supply terminal includes: AT type power supply terminal, BT type power supply terminal, alternative power supply terminal and non-standard BT type power supply terminal.

[0092] In this embodiment of the application, in order to determine the target power value output by the power supply terminal, the power supply circuit further includes graded resistors, and the PD control unit further includes an operational amplifier and a second MOS transistor.

[0093] In this configuration, one end of the tiered resistor is connected to the source of the second MOSFET in the PD control unit, and the other end is connected to the source of the first MOSFET in the PD control unit. The gate of the second MOSFET in the PD control unit is connected to the output of the operational amplifier, and the drain of the second MOSFET in the PD control unit is left floating. The power supply terminal of the operational amplifier in the PD control unit is connected to the third pin of the logic chip, the inverting input terminal of the operational amplifier is connected to the fourth pin of the logic chip, and the non-inverting input terminal of the operational amplifier is left floating. The specific internal connection structure of the PD control unit is as follows: Figure 2 As shown.

[0094] In this embodiment, the logic chip is specifically used to control the operational amplifier to turn on, thereby turning on the second MOSFET connected to the operational amplifier, which in turn causes the graded resistor to divide the voltage. In this embodiment, the graded resistor can be a resistor labeled R477. The logic chip can obtain the current after passing through the graded resistor and grade the current to determine the current level corresponding to the current. Specifically, how to determine the current level corresponding to a certain current is prior art and will not be described here.

[0095] The logic chip can obtain the type of the power supply terminal and thus determine the target power output value based on the type and current rating of the power supply terminal. In this embodiment, different types of power supply terminals may connect to different logic chip pins, so the logic chip can determine the type of power supply terminal based on the conducting pins. In this embodiment, different types of power supply terminals may also have different mark counts when connected to the logic chip due to different protocols they follow. For example, when the power supply terminal is an AT type, the logic chip counts 2 marks, and when the power supply terminal is a BT type, the logic chip counts 4 marks.

[0096] Specifically, in this embodiment, the logic chip counts one mark as follows: A preset graded voltage is applied to the power supply terminal. The number of times this preset graded voltage is applied may vary depending on the protocol followed by the power supply terminal. This graded voltage can be 14.5V-21.5V. After detecting the voltage applied to the power supply terminal, the logic chip controls the operational amplifier to turn on, thereby turning on the second MOSFET. The logic chip obtains the voltage returned from the second MOSFET to the logic chip, which is typically 6V-9V. The logic chip then controls the fifth MOSFET 205 in the PD control unit connected to it to turn on. The gate of the fifth MOSFET 205 is connected to a pin of the logic chip, and the drain of the fifth MOSFET 205 is connected to a resistor 206 included in the PD control unit. One end of the resistor 206 is connected to the drain of the fifth MOSFET. In this embodiment, after the logic chip controls the fifth MOSFET to turn on, the logic chip counts one mark. If the preset graded voltage applied to the power supply terminal is subsequently detected, the aforementioned control operational amplifier is activated, causing the second MOSFET to conduct. The voltage returned by the second MOSFET to the logic chip is then obtained. The logic chip controls the fifth MOSFET in the PD control unit connected to it to conduct. After the logic chip controls the fifth MOSFET to conduct, the logic chip receives another mark, thereby counting the corresponding mark number. In this embodiment, different power supply terminal types, different required protocols, and different numbers of times the preset graded voltage is applied to the power supply terminal result in different mark counts subsequently recorded by the logic chip.

[0097] In this embodiment, if the power supply terminal is a BT-type power supply terminal, the PD control unit also includes another operational amplifier 207 and a sixth MOSFET 208. The power supply circuit also includes a graded resistor marked R472. The specific internal connection structure of the PD control unit is as follows: Figure 2 As shown, the connection relationship between the operational amplifier 207, the sixth MOSFET 208, and the graded resistor R472 and the logic chip is similar to the connection relationship between the operational amplifier, the second MOSFET, and the graded resistor and the logic chip described above. For ease of description, the graded resistor can be referred to as R472, and the operational amplifier can be referred to as U1. Specifically, one end of R472 is connected to the source of the sixth MOSFET, and the other end of R472 is connected to the source of the first MOSFET; the gate of the sixth MOSFET is connected to the output of U1, the drain of the sixth MOSFET is floating, and the source of the sixth MOSFET is connected to one end of R472; the power supply terminal of U1 is connected to the pin of the logic chip, the inverting input terminal of U1 is connected to the pin of the logic chip, and the non-inverting input terminal of U1 is floating; the specific internal connection structure of the PD control unit is as follows. Figure 2As shown. If the power supply type is BT type, after the logic chip controls the operational amplifier to turn on, it controls the operational amplifier U1 to turn on, causing the sixth MOSFET to conduct. The logic chip obtains the voltage returned by the sixth MOSFET to the logic chip, which is usually 6V-9V. The logic chip then controls the fifth MOSFET in the PD control unit connected to it to conduct, and controls the fifth MOSFET to conduct, thereby counting the mark number.

[0098] For example, a Class 6 current rating with a mark number of 4 corresponds to a power of 50W, while a Class 4 current rating with a mark number of 2 corresponds to a power of 25W.

[0099] Example 4:

[0100] In order to protect the power supply circuit, based on the above embodiments, in this embodiment of the application, the power supply circuit further includes a delay unit;

[0101] The delay unit is connected to the PD control unit and is used to extend the startup time of the PD control unit.

[0102] In this embodiment of the application, in order to protect the power supply circuit, the power supply circuit also includes a delay unit. The delay unit is connected to the PD control unit and is used to extend the startup time of the PD control unit, thereby protecting the power supply circuit.

[0103] To protect the power supply circuit, based on the above embodiments, in this embodiment, the PD control unit further includes: a charge pump 209 and a third MOSFET 210; the delay unit includes: a first capacitor and a resistor; and the power supply circuit further includes a second capacitor. Figure 2 As shown:

[0104] One end of the charge pump 209 of the PD control unit is connected to the fifth pin of the logic chip 201 of the PD control unit, and the other end is connected to the gate of the third MOS transistor 210 of the PD control unit.

[0105] One end of the first capacitor is connected to one end of the resistor, and the other end of the resistor is connected to the gate of the third MOS transistor 210 of the PD control unit;

[0106] The source of the third MOS transistor 210 of the PD control unit is connected to one end of the second capacitor;

[0107] The other end of the second capacitor is connected to the source of the first MOS transistor 202 of the PD control unit.

[0108] In this embodiment, to prevent the power supply circuit from triggering protection and stopping operation due to an excessively large instantaneous current surge at the start of power supply, the PD control unit of the power supply circuit may further include a charge pump and a third MOSFET. The delay unit may include a first capacitor and a resistor, and the power supply circuit may also include a second capacitor. One end of the charge pump is connected to the fifth pin of the logic chip, and the other end of the charge pump is connected to the gate of the third MOSFET. One end of the first capacitor is connected to the resistor, and the other end of the first capacitor is connected to the source of the fifth MOSFET described in the above embodiment. The other end of the resistor is connected to the gate of the third MOSFET. The source of the third MOSFET is connected to one end of the second capacitor, and the drain of the third MOSFET is connected to... Figure 2 The other resistor 206 shown is not connected to one end of the fifth MOSFET, and the gate of the third MOSFET is connected to the charge pump; one end of the second capacitor is connected to the source of the third MOSFET of the PD control unit, and the other end of the second capacitor is connected to the source of the first MOSFET of the PD control unit. The specific internal connection structure of the PD control unit is as follows... Figure 2 As shown.

[0109] In this embodiment, after current flows through the logic chip at the power supply terminal, the first capacitor can be charged. Specifically, the first capacitor is charged by a charge pump through an external current-limiting resistor, which is the resistor described in this embodiment. The slow charging process of the first capacitor causes the gate voltage of the third MOS to rise slowly, causing the voltage of the connected second capacitor to rise slowly as well. Through the resistor and the first capacitor in this structure, that is, the delay unit, the current can be limited to a certain range for a period of time before the power supply terminal starts to supply power. For example, it can be limited to 350mA in the first 80ms of the power supply start, to prevent the power supply circuit from triggering protection stop due to overcurrent and stopping operation, thus preventing it from supplying power to the PD device unit. At the same time, it saves the cost of adding a separate MOS transistor to control the current output of the power supply terminal outside the power supply circuit, simplifying the power supply circuit.

[0110] Example 5:

[0111] In order to accurately output the target duty cycle information, based on the above embodiments, in this embodiment of the application, the power supply circuit further includes: a rectifier module;

[0112] One end of the rectifier module is connected to the PD control unit, and the other end is connected to the PD device unit, for adjusting the current.

[0113] In this embodiment, the power supply circuit further includes a rectifier module, one end of which is connected to the PD control unit and the other end of which is connected to the PD device unit, for adjusting the current so that the PD control unit can work normally.

[0114] In order to accurately output the target duty cycle information, based on the above embodiments, in this embodiment of the application, the rectifier module includes: a first diode and a second diode;

[0115] The positive terminal of the first diode is connected to the source of the third MOS transistor of the PD control unit, and the negative terminal of the first diode is connected to the PD device unit.

[0116] The positive terminal of the second diode is grounded, and the negative terminal of the second diode is connected to the source of the first MOS transistor of the PD control unit.

[0117] In practical applications, the power supply circuit may contain multiple PD control units. For example, a dual-port AT power supply method may be used, where the PD device unit is powered through two AT-type power supply terminals. To send the power output from these two AT-type power supply terminals to the PD device unit, each AT-type power supply terminal is connected to a corresponding PD control unit, and each PD control unit sends its corresponding duty cycle information. To prevent voltage from other PD control units from flowing through this PD control unit and causing it to malfunction, in this embodiment, the rectifier module may include a first diode. The anode of the first diode is connected to the source of a third MOSFET, and the cathode of the first diode is connected to the PD device unit. This ensures that voltage from other PD control units does not flow back into this PD control unit, preventing it from malfunctioning. Specifically, the cathode of the first diode may be connected to the PD device unit through other devices.

[0118] In practical applications, ground current may pass through the logic chip of the PD control unit, causing the logic chip to malfunction. Therefore, in this embodiment, the rectifier module may also include a second diode, the positive terminal of which is grounded and the negative terminal of which is connected to the source of the first MOS transistor of the PD control unit, thereby preventing ground current from flowing through the first MOS transistor to the logic chip and causing the logic chip to malfunction, and further preventing ground current from flowing through the logic chip to the power supply terminal.

[0119] In this embodiment, the power supply circuit may further include a third capacitor, one end of which is connected to the negative terminal of the first diode and the other end of which is grounded. The power supply circuit may further include a fourth capacitor, one end of which is connected to the end of the resistor 206 in the PD control unit that is not connected to the fifth MOSFET, and the other end of which is connected to the source of the first MOSFET, thereby filtering the PD control unit through the third and fourth capacitors.

[0120] Example 6:

[0121] In order for the PD device unit to operate normally, based on the above embodiments, in this embodiment of the application, the power supply circuit further includes: a flyback power supply module;

[0122] One end of the flyback power module is connected to the PD control unit, and the other end is connected to the PD device unit, which is used to reduce the voltage flowing through itself.

[0123] In this embodiment of the application, the power supply circuit further includes a flyback power module. One end of the flyback power module is connected to the PD control unit, and the other end is connected to the PD device unit. It is used to reduce the voltage flowing through itself, thereby avoiding excessive voltage at the power supply end, which would cause the PD device unit to malfunction.

[0124] In this embodiment, the flyback power module can be connected at one end to one end of the rectifier module, and the other end of the rectifier module can be connected to the PD control unit, thereby realizing the connection between the flyback power module and the PD control unit. The other end of the flyback power module can be connected to the PD device unit, thereby realizing the connection between the rectifier module and the PD device unit.

[0125] In order for the PD device unit to operate normally, based on the above embodiments, in this embodiment of the application, the power supply circuit further includes: a voltage regulation loop module;

[0126] One end of the voltage regulator loop module is connected to one end of the flyback power supply module connected to the PD control unit, and the other end is connected to one end of the flyback power supply module connected to the PD device unit, for controlling the flyback power supply module to turn on.

[0127] In this embodiment of the application, the power supply circuit further includes a voltage regulator loop module. One end of the voltage regulator loop module is connected to one end of the flyback power supply module connected to the PD control unit, and the other end is connected to one end of the flyback power supply module connected to the PD device unit, for controlling the flyback power supply module to turn on.

[0128] Figure 3 This is a detailed structural diagram of a power supply circuit provided in an embodiment of this application.

[0129] Depend on Figure 3It can be seen that the power supply circuit includes a PD control unit, a delay unit, a status feedback module, a rectifier module, a flyback power supply module, a voltage regulator loop module, and a PD device unit. Specifically, the delay unit is connected to the PD control unit; one end of the status feedback module is connected to the PD control unit, and the other end is connected to the PD device unit; one end of the rectifier module is connected to the PD control unit, and the other end is connected to the flyback power supply module; one end of the flyback power supply module is connected to the end of the rectifier module not connected to the PD control unit, and the other end is connected to the PD device unit; one end of the voltage regulator loop module is connected to one end of the flyback power supply module, and the other end is connected to the other end of the flyback power supply module.

[0130] Figure 4 This is a schematic diagram of the connection structure of a flyback transformer provided in an embodiment of this application.

[0131] In order for the PD device unit to operate normally, based on the above embodiments, in this embodiment of the application, the flyback power supply module is a flyback transformer; the voltage regulation loop module includes: a control chip, a third diode and a fourth MOSFET;

[0132] The positive terminal of the third diode is connected to the sixth pin of the logic chip of the PD control unit, and the negative terminal of the third diode is connected to the first control pin of the control chip.

[0133] The second control pin of the control chip is connected to the gate of the fourth MOS transistor;

[0134] The drain of the fourth MOS transistor is connected to the first transformer pin of the flyback transformer, and the source of the fourth MOS transistor is grounded.

[0135] The second transformer pin of the flyback transformer is connected to the negative terminal of the first diode, and the third and fourth transformer pins of the flyback transformer are connected to the PD device unit.

[0136] The logic chip of the PD control unit is used to send an enable signal to the control chip when sending the target duty cycle information;

[0137] The control chip is used to control the fourth MOSFET to turn on, so that the flyback transformer can be turned on.

[0138] In this embodiment, the flyback power module can be a flyback transformer, which reduces the voltage at the power supply end, thereby enabling the PD device unit to operate normally.

[0139] The voltage regulation loop module includes a control chip, a third diode, and a fourth MOSFET. The anode of the third diode is connected to the sixth pin of the logic chip of the PD control unit, the cathode of the third diode is connected to the first control pin of the control chip, the second control pin of the control chip is connected to the gate of the fourth MOSFET, the drain of the fourth MOSFET is connected to the first transformer pin of the flyback transformer, and the source of the fourth MOSFET is grounded. The second transformer pin of the flyback transformer is connected to the cathode of the first diode, and the third and fourth transformer pins of the flyback transformer are connected to the PD device unit.

[0140] In this embodiment of the application, the electronic device controls the fourth MOSFET to turn on through the control chip, thereby enabling the flyback transformer to perform the function of voltage transformation. Specifically, in this embodiment of the application, when the logic chip of the PD control unit sends the target duty cycle information, it can send an enable signal to the control chip. After receiving the enable signal, the control chip can control the fourth MOSFET to turn on, thereby enabling the flyback transformer to turn on.

[0141] Depend on Figure 4 It can be seen that the flyback transformer can be connected to the PD device unit through the fifth capacitor and the fourth diode. Specifically, the fourth transformer pin of the flyback transformer can be connected to the positive terminal of the fourth diode, the third transformer pin of the flyback transformer can be connected to the PD device unit and one end of the fifth capacitor, one end of the fifth capacitor can be connected to the third transformer pin of the flyback transformer and the PD device unit, and the other end of the fifth capacitor can be connected to the negative terminal of the fourth diode and the PD device unit.

[0142] Example 7:

[0143] In order to enable the power supply terminal to supply power to the PD device unit, based on the above embodiments, in this embodiment of the application, the power supply circuit further includes: a network port socket and a network port transformer;

[0144] The power supply terminal is connected to the network port socket, and the network port socket is connected to the network port transformer;

[0145] If the power supply terminal is an AT type power supply terminal, the power supply circuit further includes: a rectifier bridge;

[0146] The network port transformer is connected to the rectifier bridge, and the rectifier bridge is connected to the PD control unit;

[0147] If the power supply terminal is either a non-standard BE type power supply terminal or a BT type power supply terminal, the network port transformer is connected to the PD control unit.

[0148] In this embodiment, the power supply circuit further includes a network port socket and a network port transformer. The power supply circuit is connected to the network port socket, and the network port socket is connected to the network port transformer.

[0149] In this embodiment, if the power supply terminal is an AT type power supply terminal, the power supply circuit further includes: a rectifier bridge, a network port transformer connected to the rectifier bridge, and the rectifier bridge connected to the PD control unit. If the power supply terminal is either a non-standard BT type power supply terminal or a BT type power supply terminal, the network port transformer is connected to the PD control unit.

[0150] In this embodiment, if the power supply is an AT type power supply, the output of the AT type power supply can be connected to a network port socket via a network cable, and then sequentially connected to a network port transformer, a rectifier bridge, a PD control unit, and a PD device unit to supply power to the PD device unit. The rectifier bridge is an existing structure, and its structure will not be described in detail here.

[0151] If the power supply is either a non-standard BT type power supply or a BT type power supply, the output of the power supply can be connected to the network port socket via a network cable, and then connected to the network port transformer, PD control unit, flyback transformer and PD device unit in sequence, thereby supplying power to the PD device unit.

[0152] Figure 5 This is a schematic diagram of the network port socket and network port transformer provided in the embodiments of this application.

[0153] Depend on Figure 5It can be seen that when connecting the network port socket and the network port transformer, the pins marked with the same information on the network port socket and the network port transformer can be connected. That is, connect the pins marked "WAN1_TE4_+" on both the network port socket and the network port transformer, connect the pins marked "WAN1_TE4_-", connect the pins marked "WAN1_TE3_+", connect the pins marked "WAN1_TE3_-", connect the pins marked "WAN1_TE2_+", connect the pins marked "WAN1_TE2_-", connect the pins marked "WAN1_TE1_+", and connect the pins marked "WAN1_TE1_-". In other words, connect pin 1 of the network port socket... Connect pin 11 of the network port transformer; connect pin 2 of the network port socket to pin 12 of the network port transformer; connect pin 3 of the network port socket to pin 5 of the network port transformer; connect pin 4 of the network port socket to pin 6 of the network port transformer; connect pin 5 of the network port socket to pin 6 of the network port transformer; connect pin 6 of the network port socket to pin 9 of the network port transformer; connect pin 7 of the network port socket to pin 2 of the network port transformer; connect pin 8 of the network port socket to pin 3 of the network port transformer. The connection of the other pins of the network port transformer and network port socket is not restricted. After power is applied to the power supply, the current can flow through the network port socket, and the current in the network port socket can flow through the network port transformer through the pins connected to the network port transformer. This isolates the power supply from other devices through the network port transformer, enhancing its anti-interference capability and protecting it.

[0154] In order to enable the power supply terminal to supply power to the PD device unit, based on the above embodiments, in this embodiment of the application, if the power supply terminal is an alternative power supply terminal, the power supply circuit further includes: a fourth diode;

[0155] The alternative power supply terminal is connected to the positive terminal of the fourth diode, and the negative terminal of the fourth diode is connected to the ninth pin of the logic chip of the PD control unit.

[0156] In this embodiment of the application, if the power supply terminal is an alternative power supply terminal, the power supply circuit further includes a fifth diode. The positive terminal of the fifth diode is connected to the alternative power supply terminal, and the negative terminal of the fifth diode is connected to the seventh pin of the logic chip of the PD control unit.

[0157] In this embodiment, if the power supply terminal is an alternative power supply terminal, it can be connected to the PD device unit through two PD control units. If the PD device unit is connected through two PD control units, the power supply circuit includes two fifth diodes, which are respectively connected to the pins of the two PD control units.

[0158] Figure 6This is a schematic diagram of the connection structure of an alternative power supply terminal provided in an embodiment of this application.

[0159] Depend on Figure 6 It can be seen that one end of the alternative power supply terminal can be connected to the anode of diode Z072, one end of resistor R110, one end of capacitor CD1, and the source of the seventh MOSFET. The other end of the alternative power supply terminal can be connected to the cathode of diode Z081. The cathode of diode Z072 can be connected to the other end of resistor R110, one end of resistor R109, the other end of capacitor CD1, and the gate of the seventh MOSFET. The other end of resistor R109 can be connected to the anode of diode Z071. The cathode of diode Z071 can be connected to the anodes of fifth diode DA4 and fifth diode DB4. The cathodes of fifth diode DA4 and fifth diode DB4 are respectively connected to two PD control units. The cathodes of fifth diode DA4 and fifth diode DB4 can be connected to the source of the third MOSFET, thereby connecting to the PD control unit through the third MOSFET. The anodes of fifth diode DA4 and fifth diode DB4 can also be connected to the pins of the logic chip in the PD control unit.

[0160] The positive terminals of the fifth diode DA4 and the fifth diode DB4 are connected to one end of resistor R1 in the power supply circuit. The output terminal of operational amplifier U2 in the PD control unit is connected to a pin of the logic chip, allowing the current from the alternative power supply terminal to flow through the logic chip. The positive input terminal of U2 is floating, and the negative input terminal is connected to the other end of resistor R1. One end of resistor R2 is connected to resistor R1, and the other end is connected to the source of the first MOSFET. In this embodiment, the voltage of the alternative power supply terminal can be sampled by voltage divider R1 and R2. When the voltage is greater than the voltage on the U2 side, the logic chip detects the current and determines that the alternative power supply terminal has started supplying power, thus starting operation.

[0161] In this configuration, the cathodes of diodes DA3 and DB3 are connected to the drain of the seventh MOSFET, and the cathodes of diodes DA3 and DB3 are connected to one end of capacitor C1. The cathodes of the fifth diodes DA4 and DB4 are connected to the other end of capacitor C1. The anodes of diodes DA3 and DB3 are connected to the source of the first MOSFET, thereby supplying power to the PD control unit and enabling it to operate normally.

[0162] In particular, diodes DA3 and DB3 ensure that the power supply to the two PD control units is returned to the backup power supply terminal, so that the two PD control units can output normal status levels.

[0163] In this embodiment, since the alternative power supply terminal and the non-standard BT type power supply terminal do not need to follow the corresponding protocol, the logic chip does not need to perform mark statistics.

[0164] Figure 7 This is a complete schematic diagram of a PD control unit and connected devices provided in an embodiment of this application.

[0165] Depend on Figure 7 It is known that the PD control unit includes a logic chip 201, a first MOS transistor 202 that outputs a duty cycle signal, a charge pump 209, an operational amplifier 203 and a second MOS transistor 204 for counting mark numbers, another operational amplifier 207 and a sixth MOS transistor 208 and a fifth MOS transistor 205 for counting mark numbers, a resistor 206, a third MOS transistor 210, and an operational amplifier U2 for connecting to an alternative power supply terminal.

[0166] Depend on Figure 6 It can be seen that the output terminal of U2 is connected to the pin of logic chip 201, the positive input terminal of U2 is floating, the negative input terminal is connected to one end of resistor R1, and the other end of resistor R1 is connected to... Figure 6 The positive terminal of the fourth diode DA4 or the fourth diode DB4 is connected. One end of resistor R2 is connected to resistor R1, and the other end is connected to the source of the first MOSFET 202. The power supply circuit includes a step resistor R477, one end of which is connected to the source of the second MOSFET 204, and the other end of which is connected to the source of the first MOSFET 202. The gate of the second MOSFET 204 is connected to the output of the operational amplifier 203, the drain of the second MOSFET 204 is floating, and the source of the second MOSFET 204 is connected to one end of the step resistor R477. The power supply terminal of the operational amplifier 203 is connected to the pin of the logic chip 201, the inverting input terminal of the operational amplifier 203 is connected to the pin of the logic chip 201, and the non-inverting input terminal of the operational amplifier 203 is floating. The power supply circuit includes a step resistor R472, one end of which is connected to the source of the sixth MOSFET 208, and the other end of which is connected to the source of the first MOSFET 202; the gate of the sixth MOSFET 208 is connected to the output of the operational amplifier 207, the drain of the sixth MOSFET 208 is floating, and the source of the sixth MOSFET 208 is connected to one end of the step resistor R472; the power supply terminal of the operational amplifier 207 is connected to the pin of the logic chip 201, the inverting input terminal of the operational amplifier 207 is connected to the pin of the logic chip 201, and the non-inverting input terminal of the operational amplifier 203 is floating.

[0167] Depend on Figure 6It can be seen that one end of the second capacitor in the power supply circuit is connected to the anode of the first diode, and the other end of the second capacitor is connected to the cathode of the second diode. One end of the fifth capacitor is connected to the unconnected end of resistor 206, and the other end is connected to the source of the first MOSFET. The anode of the first diode is connected to the source of the third MOSFET, and the cathode of the first diode is connected to... Figure 4 The flyback transformer connection shown has the cathode of the second diode connected to the source of the first MOSFET, and the anode of the second diode grounded. The anode of the third diode is connected to a pin of logic chip 201, and the cathode of the third diode is... Figure 4 The pin connections of the control chip in the system.

[0168] Depend on Figure 6 It can be seen that one end of the charge pump 209 is connected to the pin of the logic chip 201, and the other end of the charge pump 209 is connected to the gate of the third MOSFET 205; one end of the first capacitor is connected to the source of the fifth MOSFET 205, the other end of the first capacitor is connected to the resistor in the delay unit, and the other end of the resistor is connected to the gate of the third MOSFET 205; the source of the third MOSFET 205 is connected to the cathode of the first diode, the gate of the third MOSFET 205 is connected to the charge pump 209, and the drain of the third MOSFET 205 is connected to one end of the resistor 206.

[0169] Example 8:

[0170] In this embodiment of the application, the alternative power supply terminal and the non-standard BT type power supply terminal do not need to follow the corresponding protocol. When the power supply terminal is the alternative power supply terminal or the non-standard BT type power supply terminal, the PD device unit operates according to the power corresponding to the alternative power supply terminal or the non-standard BT type power supply terminal. For example, if the output power of the non-standard BT type power supply terminal is 50W, the PD device unit will operate according to 50W.

[0171] In one possible implementation, if the power supply is an alternative power supply, the PD control unit outputs information with a 75% duty cycle, with 75% of the output being high-level. If the power supply is a BT type power supply and the BT type power supply outputs the highest power, the PD control unit outputs information with a 50% duty cycle, with 50% of the output being high-level. If the power supply is a non-standard BT type power supply, the PD control unit outputs high-level information. If the power supply is an AT type power supply and the AT type power supply outputs the highest power, the PD control unit can output low-level information. The specific duty cycle corresponding to each power level can be set according to requirements and is not limited here.

[0172] In this embodiment of the application, if the power supply terminal is a backup power supply terminal, since the maximum power value of the backup power supply terminal is greater than the maximum operating power of the PD device unit, the PD device unit can operate at the maximum operating power, that is, at full power.

[0173] Figure 8 This is a schematic diagram illustrating the process by which a PD device unit determines its operating power when the power supply is operating at its maximum power, as provided in an embodiment of this application.

[0174] Depend on Figure 8 It can be seen that when the PD device unit receives the duty cycle information, if the duty cycle is the same as that corresponding to the alternative power supply terminal, such as 75%, the PD device unit will operate according to its own maximum operating power value; if the duty cycle is the same as that corresponding to the BT type power supply terminal, it will operate according to the standard BT power, that is, according to 50W; if the duty cycle is the same as that corresponding to the non-standard BT type power supply terminal, it will operate according to the non-standard BT power; if the received information is the duty cycle corresponding to the AT type power supply terminal, it will check whether other input / output (IO) ports have received the duty cycle information, thereby determining the number of AT type power supplies. If the number of AT type power supplies is 1, it will operate according to the standard AT power, that is, according to 25W; if the number of AT type power supplies is 2, it will operate according to the standard AT power, that is, according to 50W.

[0175] This application also provides a network device, which includes a power supply circuit.

[0176] The power supply device is the same as the power supply device described in the above embodiments. The specific components included in the power supply circuit have been described in the above embodiments and will not be described in detail here.

[0177] In this embodiment, the PD control unit of the power supply circuit detects the target power value output by the connected power supply terminal and outputs the target duty cycle information corresponding to the target power value. The PD device unit determines the corresponding operating power value based on the target duty cycle information, so that the PD device unit can operate according to the corresponding operating power value. Since the PD control unit only needs to send the target duty cycle information to the PD device unit through one pin of the PD control unit, the circuit of this embodiment is not complicated and occupies less space.

Claims

1. A power supply circuit, characterized in that, The power supply circuit includes: a power receiving PD control unit and a power receiving PD device unit; The PD control unit is connected to the PD device unit and is used to detect the target power value output by the connected power supply terminal, determine the target duty cycle corresponding to the target power value according to the pre-stored correspondence between power value and duty cycle, and send the target duty cycle information to the PD device unit based on a pin of the PD control unit. The PD device unit is used to determine the corresponding operating power value based on the target duty cycle information, so that the PD device unit operates according to the operating power value.

2. The power supply circuit according to claim 1, characterized in that, The PD control unit includes: a logic chip and a first field-effect MOSFET; The first pin of the logic chip of the PD control unit is connected to the power supply terminal; the second pin of the logic chip of the PD control unit is connected to the gate of the first MOS transistor of the PD control unit. The drain of the first MOS transistor in the PD control unit is connected to the PD device unit; The logic chip of the PD control unit is used to detect the target power value output by the connected power supply terminal, determine the target duty cycle corresponding to the target power value according to the pre-stored correspondence between the power value and the duty cycle, and control the first MOS transistor of the PD control unit to turn on according to the target duty cycle.

3. The power supply circuit according to claim 1 or 2, characterized in that, The power supply circuit also includes: a status feedback module; One end of the status feedback module is connected to the PD control unit, and the other end is connected to the PD device unit. It is used to receive the target duty cycle information sent by the PD control unit and send the target duty cycle information to the PD device unit.

4. The power supply circuit according to claim 3, characterized in that, The status feedback module is a status feedback optocoupler; One end of the status feedback optocoupler is connected to the drain of the first MOS transistor of the PD control unit, and the other end of the status feedback optocoupler is connected to the PD device unit, for sending the target duty cycle information to the PD device unit.

5. The power supply circuit according to claim 1 or 2, characterized in that, The power supply circuit further includes: graded resistors; the PD control unit further includes: an operational amplifier and a second MOSFET; One end of the graded resistor is connected to the source of the second MOS transistor of the PD control unit, and the other end of the graded resistor is connected to the source of the first MOS transistor of the PD control unit. The gate of the second MOS transistor of the PD control unit is connected to the output terminal of the operational amplifier of the PD control unit, and the drain of the second MOS transistor of the PD control unit is left floating. The power supply terminal of the operational amplifier of the PD control unit is connected to the third pin of the logic chip of the PD control unit, the inverting input terminal of the operational amplifier of the PD control unit is connected to the fourth pin of the logic chip of the PD control unit, and the non-inverting input terminal of the operational amplifier of the PD control unit is left floating. The logic chip of the PD control unit is used to control the operational amplifier of the PD control unit to turn on, so as to turn on the second MOS transistor of the PD control unit; to obtain the current flowing through the graded resistor, to determine the current level corresponding to the current, and to determine the target power value of the power supply terminal according to the type of the power supply terminal and the current level; wherein, the type of the power supply terminal includes: AT type, BT type, alternative type and non-standard BT type.

6. The power supply circuit according to claim 1 or 2, characterized in that, The power supply circuit also includes: a delay unit; The delay unit is connected to the PD control unit and is used to extend the startup time of the PD control unit.

7. The power supply circuit according to claim 6, characterized in that, The PD control unit further includes: a charge pump and a third MOSFET; the delay unit includes: a first capacitor and a resistor; and the power supply circuit further includes a second capacitor. One end of the charge pump of the PD control unit is connected to the fifth pin of the logic chip of the PD control unit, and the other end is connected to the gate of the third MOS transistor of the PD control unit. One end of the first capacitor is connected to one end of the resistor, and the other end of the resistor is connected to the gate of the third MOS transistor of the PD control unit; The source of the third MOS transistor in the PD control unit is connected to one end of the second capacitor; The other end of the second capacitor is connected to the source of the first MOS transistor of the PD control unit.

8. The power supply circuit according to claim 1 or 2, characterized in that, The power supply circuit also includes: a rectifier module; One end of the rectifier module is connected to the PD control unit, and the other end is connected to the PD device unit, for adjusting the current.

9. The power supply circuit according to claim 8, characterized in that, The rectifier module includes: a first diode and a second diode; The positive terminal of the first diode is connected to the source of the third MOS transistor of the PD control unit, and the negative terminal of the first diode is connected to the PD device unit. The positive terminal of the second diode is grounded, and the negative terminal of the second diode is connected to the source of the first MOS transistor of the PD control unit.

10. The power supply circuit according to claim 1 or 2, characterized in that, The power supply circuit also includes: a flyback power module; One end of the flyback power module is connected to the PD control unit, and the other end is connected to the PD device unit, which is used to reduce the voltage flowing through itself.

11. The power supply circuit according to claim 10, characterized in that, The power supply circuit also includes: a voltage regulator loop module; One end of the voltage regulator loop module is connected to one end of the flyback power supply module connected to the PD control unit, and the other end is connected to one end of the flyback power supply module connected to the PD device unit, for controlling the flyback power supply module to turn on.

12. The power supply circuit according to claim 11, characterized in that, The flyback power supply module is a flyback transformer; the voltage regulation loop module includes: a control chip, a third diode, and a fourth MOSFET. The positive terminal of the third diode is connected to the sixth pin of the logic chip of the PD control unit, and the negative terminal of the third diode is connected to the first control pin of the control chip. The second control pin of the control chip is connected to the gate of the fourth MOS transistor; The drain of the fourth MOS transistor is connected to the first transformer pin of the flyback transformer, and the source of the fourth MOS transistor is grounded. The second transformer pin of the flyback transformer is connected to the negative terminal of the first diode, and the third and fourth transformer pins of the flyback transformer are connected to the PD device unit. The logic chip of the PD control unit is used to send an enable signal to the control chip when sending the target duty cycle information; The control chip is used to control the fourth MOSFET to turn on, so that the flyback transformer can be turned on.

13. A network device, characterized in that, The network device includes a power supply circuit as described in any one of claims 1-12.

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