A PD charging circuit and charging method for automatically compensating for line loss

Abstract

The present invention relates to a PD charging circuit and charging method that automatically compensates for line loss. The circuit includes a Type C interface, a PD protocol chip, and a PD power conversion module. An input voltage Vin is input to the PD power conversion module, which performs voltage conversion on the input voltage Vin and outputs a converted voltage VBUS after filtering. The voltage of the converted voltage VBUS after passing through a wire is a post-line output voltage Vo, which is provided to a powered device. Due to the parasitic resistance R2 of the wire itself, a voltage drop occurs between the converted voltage VBUS and the post-line output voltage Vo. The DC-DC converter chip uses a current detection amplifier unit to detect the current of the powered device in real time, obtains a preset range within which the current value falls, and adjusts the voltage of the converted voltage VBUS to a voltage corresponding to the preset current range, thereby ensuring that the post-line output voltage Vo reaches a set value. The voltage is then output to the Type C interface via the wire.

Description

Technical Field

[0001] The present invention relates to the field of direct current (DC) charging technology, and more particularly to a PD charging circuit and charging method capable of automatically compensating for line loss. Background Art

[0002] Due to its powerful electrical performance specifications and ease of use, TYPE C is increasingly becoming a standard interface for various electronic products, such as monitors, mobile phones, tablets, laptops and power adapters. The PD charging function is a core parameter among the various performance specifications of TYPE C.

[0003] Because PD charging draws high current (the standard upper limit is 100W), the line loss and voltage after transmitting this high current through the Type C cable are also significant, especially when the Type C cable is long. This results in a low voltage reaching the terminal, even below the terminal's minimum voltage specification. Therefore, designers face the challenge of increasing the actual voltage received by the terminal.

[0004] Line loss voltage = transmission current * wire DC resistance. The DC resistance of a wire is determined solely by its raw material, shape (including diameter), and length. This means the wire remains largely unchanged after leaving the factory. Line loss voltage is determined by the transmission current.

[0005] Currently, there are three common methods for reducing line loss: (a) reducing the length of the Type C cable, which is inconvenient for large-scale products; (b) changing the transmission line material: for example, using better, lower-impedance wire, such as replacing copper wire with silver or gold, which increases the cost of the Type C cable; or using thicker wire, which also increases the cost of the Type C cable, but the diameter can be increased to a limited extent; too thick a wire cannot be soldered to a standard Type C connector. (c) Setting the PD to a fixed, slightly higher voltage output, such as changing from 5V to 5.3V, will increase the actual voltage at the terminal by 0.3V, regardless of the voltage loss caused by the Type C cable. A drawback of this solution is that when the terminal is lightly loaded (low current 0A / 0.1A / 0.2A, etc.), the actual voltage received by the terminal is also higher, 5.3V (not 5.0V). This is because the voltage loss caused by the Type C cable is also small at low current. This "high voltage" can be dangerous for some terminal devices that require very precise voltages. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a PD charging circuit that automatically compensates for line loss in response to the above-mentioned defects of the prior art.

[0007] The technical solution adopted by the present invention to solve its technical problem is:

[0008] A charging device that automatically compensates for line loss is constructed, comprising a Type C interface, a PD protocol chip, and a PD power conversion module; the voltage input end of the Type C interface is connected to the voltage output end of the PD power conversion module, the voltage input end of the PD power conversion module is connected to an external power supply, the control signal input end of the PD power conversion module is connected to the control signal output end of the PD protocol chip, and the CC signal connection end of the PD protocol chip is connected to the CC signal connection end of the Type C interface; the charging device is connected to a device to be charged via the Type C interface, wherein:

[0009] The PD protocol chip is used to determine the required voltage of the powered device and control the PD power conversion module to convert the input voltage Vin into the required voltage of the powered device;

[0010] The PD power conversion module is used to convert the input voltage Vin and output the converted voltage VBUS after filtering. It is also used to sample the current of the output current path and dynamically adjust the converted voltage VBUS according to the sampled current so that the post-line output voltage Vo reaches the required voltage value of the powered device;

[0011] The TYPE C interface is used to provide a powered device with a line output voltage Vo formed by the converted voltage VBUS passing through a wire.

[0012] Preferably, the voltage conversion module includes a DC-DC conversion chip, a switching circuit, a filter circuit and a sampling resistor, the input end of the switching circuit is connected to the power supply, the output end is connected to the input end of the filter circuit, the control end is connected to the DC-DC conversion chip, the output end of the filter circuit is connected to the positive input end of the sampling resistor, and the negative input end of the sampling resistor is connected to the Type C interface.

[0013] Preferably, the DC-DC conversion chip is provided with a PWM control unit, a drive unit and a current detection amplifier unit, the PWM control unit is connected to the current detection amplifier unit, both ends of the sampling resistor are connected to the current detection amplifier unit, and the switching circuit includes a power switch tube K1.

[0014] Preferably, the filtering circuit includes an inductor L, a first capacitor C1 and a second capacitor C2, one end of the inductor, the first capacitor C1 and the second capacitor C2 are all connected to the positive input end of the sampling resistor, the negative input end of the sampling resistor is connected to the Type C interface, the other end of the inductor is connected to the switching circuit, and the other ends of the first capacitor C1 and the second capacitor C2 are both grounded.

[0015] Preferably, the power switch tube K1 is a PMOS tube or an NMOS tube, the gate of the power switch tube K1 is connected to the PWM control unit, the source is connected to the power supply, and the drain is connected to the filter circuit.

[0016] Preferably, the PWM control unit outputs a switch drive signal, the switch drive signal is input into the drive unit, the output end of the drive unit is connected to the control end of the power switch tube K1, and the drive unit controls the opening and closing of the power switch tube K1 according to the switch drive signal output by the PWM control module.

[0017] Preferably, the switch circuit includes a first MOS transistor U48, a second MOS transistor U49, a third MOS transistor U50 and a fourth MOS transistor U51.

[0018] The present invention also provides a PD charging method with automatic line loss compensation, based on the aforementioned PD charging circuit with automatic line loss compensation, comprising the following steps:

[0019] Step 1: The PD protocol chip detects that the TYPE C interface is connected to the powered device, and then performs standard PD protocol communication with the powered device to identify the voltage requirement of the powered device;

[0020] Step 2: The PD protocol chip inputs the control signal into the DC-DC converter chip, and the DC-DC converter chip converts the input voltage Vin according to the control signal, and outputs the converted voltage VBUS after filtering by the filter circuit;

[0021] Step 3: The DC-DC converter chip detects the current value of the output current Io in real time through the current detection amplifier unit to determine whether the current value is within the preset range. If the current value is within the preset range, step 4 is executed; if the current value is not within the preset range, step 5 is executed.

[0022] Step 4: Determine the preset range of the current value, and adjust the voltage of the conversion voltage VBUS to a voltage corresponding to the preset current range;

[0023] Step 5: The voltage VBUS is converted into a line output voltage Vo that meets the requirements of the powered device after passing through the wire, and the line output voltage Vo is output to the TYPE C interface.

[0024] Preferably, in step 2, the value of the converted voltage VBUS is the voltage value of the required voltage of the powered device, and in step 4, the value of the converted voltage VBUS is not higher than 105% of the required voltage value.

[0025] The present invention has the following beneficial effects: after the PD protocol chip detects that the Type C interface is connected to the powered device, it conducts standard PD protocol communication with the powered device, identifies the voltage requirements of the powered device, and inputs the input voltage Vin to the PD power conversion module. The PD power conversion module converts the input voltage Vin and outputs the converted voltage VBUS after filtering. The voltage of the converted voltage VBUS after passing through the wire is the line output voltage Vo, which is provided to the powered device. Due to the parasitic resistance R2 of the wire itself, a voltage drop occurs between the converted voltage VBUS and the line output voltage Vo. The DC-DC converter chip uses a current detection amplifier unit to detect the current of the powered device in real time, obtains the preset range within which the current value falls, and adjusts the voltage of the converted voltage VBUS to the voltage corresponding to the preset current range, thereby ensuring that the line output voltage Vo reaches the set value and is output to the Type C interface through the wire. This greatly reduces the variation of the output voltage under different load currents. The present invention is also simple to implement. It only requires presetting multiple sets of voltage / current values ​​in the chip's dedicated registers, and then dynamically adjusting the voltage output according to the actual current required by the terminal device to compensate for the Type C interface. C's inherent line loss voltage can be used to achieve line loss compensation; when the present invention is applied to a charger, constant voltage / constant current control can be achieved. Compared with traditional chargers, there is no need to increase circuit input and output ports and external components. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the present invention will be further described below with reference to the accompanying drawings and embodiments. The drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive efforts.

[0027] Figure 1 This is a structural block diagram of a PD charging circuit that automatically compensates for line loss in a preferred embodiment of the present invention;

[0028] Figure 2 1 is a circuit diagram of a PD charging circuit that automatically compensates for line loss according to a preferred embodiment of the present invention;

[0029] Figure 3 This is a flow chart of a PD charging method for automatically compensating for line loss according to a preferred embodiment of the present invention;

[0030] Figure 4 This is a circuit diagram of a PD power conversion module of a PD charging circuit that automatically compensates for line loss in another preferred embodiment of the present invention;

[0031] Figure 5 This is a circuit diagram of a PD protocol chip connection of a PD charging circuit that automatically compensates for line loss according to another preferred embodiment of the present invention;

[0032] Figure 6 This is a table of actual charging experimental data of the PD charging method with automatic compensation for line loss in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0033] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the following will be a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work shall fall within the scope of protection of the present invention.

[0034] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), such directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0035] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features specified as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0036] The PD charging circuit for automatically compensating line loss in a preferred embodiment of the present invention is as follows: Figure 1 As shown, see Figure 2 、 Figure 6 , including a Type C interface 1, a PD protocol chip 2 and a PD power conversion module 3; the voltage input end of the Type C interface 1 is connected to the voltage output end of the PD power conversion module 3, the voltage input end of the PD power conversion module 3 is connected to an external power supply, the control signal input end of the PD power conversion module 3 is connected to the control signal output end of the PD protocol chip 2, and the CC signal connection end of the PD protocol chip 2 is connected to the CC signal connection end of the Type C interface 1; the charging device is connected to the device to be charged via the Type C interface, wherein:

[0037] PD protocol chip 2, used to determine the required voltage of the powered device and control the PD power conversion module 3 to convert the input voltage Vin into the required voltage of the powered device;

[0038] PD power conversion module 3 is used to convert the input voltage Vin and output the converted voltage VBUS after filtering. It is also used to sample the current in the output current path and dynamically adjust the converted voltage VBUS based on the sampled current so that the post-line output voltage Vo meets the required voltage value of the powered device;

[0039] TYPE C interface, used to provide the line output voltage Vo formed by the converted voltage VBUS through the wire to the powered device;

[0040] After the PD protocol chip 2 detects that the Type C interface is connected to the powered device, it communicates with the powered device through the standard PD protocol, identifies the voltage requirements of the powered device, and inputs the input voltage Vin to the PD power conversion module 3. The PD power conversion module 3 converts the input voltage Vin and outputs the converted voltage VBUS after filtering. The voltage of the converted voltage VBUS after passing through the wire is the line output voltage Vo, which is provided to the powered device. Due to the parasitic resistance R2 of the wire itself, a voltage drop occurs between the converted voltage VBUS and the line output voltage Vo. The DC-DC converter chip 31 uses the current detection amplifier unit 313 to detect the current of the powered device in real time, obtains the preset range within which the current value falls, and adjusts the voltage of the converted voltage VBUS to the voltage corresponding to the preset current range, so that the line output voltage Vo reaches the set value, and then outputs it to the Type C interface through the wire. This greatly reduces the variation of the output voltage under different load currents. At the same time, the present invention is simple to implement. It only needs to preset multiple sets of voltage / current values ​​in the chip's dedicated registers, and then dynamically adjust the voltage output according to the actual current required by the terminal device to compensate for the Type C interface. C's inherent line loss voltage can be used to achieve line loss compensation; when the present invention is applied to a charger, constant voltage / constant current control can be achieved. Compared with traditional chargers, there is no need to increase circuit input and output ports and external components.

[0041] like Figure 1-2 As shown, the voltage conversion module includes a DC-DC converter chip 31, a switch circuit 32, a filter circuit 33, and a sampling resistor R1. The input end of the switch circuit 32 is connected to the power supply, the output end is connected to the input end of the filter circuit 33, and the control end is connected to the DC-DC converter chip 31. The output end of the filter circuit 33 is connected to the positive input end of the sampling resistor R1, and the negative input end of the sampling resistor R1 is connected to the Type C interface 1.

[0042] The DC-DC conversion chip model is SC8815, which is a fast charging detection chip that can manage rechargeable batteries. It is a synchronous buck-boost charging controller. The positive input of the current detection amplifier unit is connected to the SNS2P port, and the negative input is connected to the SNS2N port. The current detection amplifier unit samples the voltage difference between the SNS2N port and the SNS2P port, and uses this voltage difference to reflect the output current flowing through the sampling resistor R2 connected between the SNS2P port and the SNS2N port.

[0043] like Figure 2 As shown, the DC-DC conversion chip 31 is provided with a PWM control unit 311, a driving unit 312 and a current detection amplifier unit 313. The PWM control unit 311 and the current detection amplifier unit 313 are connected, and both ends of the sampling resistor R1 are connected to the current detection amplifier unit 313. The switch circuit 32 includes the driving unit 312;

[0044] The PWM control unit 311 is connected to the output end of the current detection amplifier unit for receiving the sampled current sent by the current detection amplifier unit, generates a PWM control signal based on the sampled current control, and sends the PWM control signal to the drive unit 312 through the PWM end. The PWM control signal has a predetermined duty cycle. The control end of the drive unit 312 is connected to the PWM end of the PWM control unit 311. The input end of the PWM control unit 311 is connected to the power input end, and the output end of the drive unit 312 is connected to the power switch tube K1. The drive unit 312 and the power switch tube K1 are used to receive the PWM control signal and adjust the duty cycle of the conduction time of their input and output ends according to the PWM control signal to adjust the output voltage. In the above process, the PWM control unit 311 can determine the line loss by detecting the current of the sampling resistor R1, and then determine the PWM control signal output to the PWM voltage modulation module according to the voltage divider value of the sampling resistor R1. The PWM voltage modulation module controls the duty cycle of the conduction time of its input and output ends by the PWM control signal, thereby achieving the regulation of the voltage output by the power supply pin of the USB interface. Since the charging voltage is compensated according to the actual USB line loss in this process to make up for the voltage drop caused by the line loss, the USB charging voltage can comply with relevant certification rules.

[0045] like Figure 2As shown, the filtering circuit 33 includes an inductor L, a first capacitor C1, and a second capacitor C2. One end of the inductor, the first capacitor C1, and the second capacitor C are all connected to the positive input end of the sampling resistor R1, the negative input end of the sampling resistor R1 is connected to the Type C interface 1, the other end of the inductor is connected to the switching circuit, and the other ends of the first capacitor C1 and the second capacitor C2 are both grounded; the inductor L is used to eliminate the ripple of the output voltage of the DC-DC converter chip U1, and combined with the filtering of the capacitors C2 and C1, a TVS diode TVS2 can also be added to the circuit for voltage stabilization, which can enable the DC-DC converter chip U1 to output a stable voltage.

[0046] like Figure 2 As shown, the power switch tube K1 is a PMOS tube or an NMOS tube, the gate of the power switch tube K1 is connected to the PWM control unit 311 , the source is connected to the power supply, and the drain is connected to the input end of the filter circuit 33 .

[0047] like Figure 2 As shown, the PWM control unit 311 outputs a switch drive signal, which is input to the drive unit 312. The output end of the drive unit 312 is connected to the control end of the power switch tube K1. The drive unit 312 controls the opening and closing of the power switch tube K1 according to the switch drive signal output by the PWM control module. When the output of the PWM control unit is a high level, the power switch K1 is controlled to be turned on through the switch drive module; when the output of the PWM control unit is a low level, the power switch K1 is controlled to be turned off through the switch drive module.

[0048] like Figure 2 As shown, the power switch tube K1 can be integrated into the DC-DC conversion chip 31. In this case, the power switch tube K1 is a PMOs tube. The source of the power switch tube K1 serves as the Vin port of the DC-DC conversion chip, the drain of the power switch tube K1 serves as the SW port of the voltage converter, and the gate is connected to the PWM control unit.

[0049] The PD charging method for automatically compensating line loss in a preferred embodiment of the present invention is as follows: Figure 1 As shown, based on the aforementioned automatic compensation line loss PD charging circuit, as Figure 3 As shown, the following steps are included:

[0050] Step 1: The PD protocol chip 2 detects that the TYPE C interface 1 is connected to the powered device, and then performs standard PD protocol communication with the powered device to identify the voltage requirement of the powered device;

[0051] Step 2: The PD protocol chip 2 inputs the control signal into the DC-DC converter chip 31. The DC-DC converter chip 31 converts the input voltage Vin according to the control signal and outputs the converted voltage VBUS after filtering by the filter circuit 33.

[0052] Step 3: The DC-DC converter chip 31 detects the output current Io in real time through the current detection amplifier unit 313 to determine whether the current value is within the preset range. If the current value is within the preset range, step 4 is executed; if the current value is not within the preset range, step 5 is executed.

[0053] Step 4: Determine the preset range of the current value, and adjust the voltage of the conversion voltage VBUS to a voltage corresponding to the preset current range;

[0054] Step 5: The voltage VBUS is converted into a line output voltage Vo that meets the requirements of the powered device after passing through the wire, and the line output voltage Vo is output to the TYPE C interface.

[0055] like Figure 3 As shown, the register in the DC-DC conversion chip 31 is preset with multiple current intervals corresponding to the voltage required by the device, and the optimal output voltage values ​​corresponding to the multiple current intervals. The PWM control unit 311 controls the power switch tube K1 to convert the voltage of the conversion voltage VBUS into the optimal output voltage value.

[0056] like Figure 3 As shown, in step 2, the value of the converted voltage VBUS is the voltage value of the required voltage of the powered device, and in step 4, the value of the converted voltage VBUS is not higher than 105% of the required voltage value;

[0057] This embodiment takes a conventional 90W PD charger as an example. Figure 6 The standard design values ​​are 5V / 3A, 9V / 3A, 12V / 3A, 15V / 3A, and 20V / 4.5A. Assuming the line loss of the Type C cable is 0.1V / A, when the output current is 0-1A, the wire will produce a voltage drop of 0-0.1V, which has little impact on the output voltage, so there is no need to adjust the conversion voltage VBUS; when the output current is 1-2A, the wire will produce a voltage drop of 0.1-0.2V, and the conversion voltage VBUS value needs to be increased by 2%-3%; when the output current is 2-3A, the wire will produce a voltage drop of 0.2-0.3V, and the conversion voltage VBUS value needs to be increased by 3%-5%; when the output current is above 3A, the conversion voltage VBUS value should be increased by 5%.

[0058] The present invention also provides another preferred embodiment of the PD charging circuit for automatically compensating line loss, such as Figure 4-5As shown, this embodiment is similar to the previous embodiment, except that the switch circuit includes a first MOS transistor U48, a second MOS transistor U49, a third MOS transistor U50, and a fourth MOS transistor U51. The gates of the first MOS transistor U48, the second MOS transistor U49, the third MOS transistor U50, and the fourth MOS transistor U51 are respectively connected to the HD1, HD2, LD1, and LD2 pins of the DC-DC converter chip. The drain of the first MOS transistor U48 is connected to the power supply, and the source is connected to the drain of the third MOS transistor U50. The source of the third MOS transistor U50 is connected to the source of the fourth MOS transistor U51. The drain of the fourth MOS transistor U51 is connected to the source of the second MOS transistor U49. The drain of the second MOS transistor U49 is connected to the positive input terminal of the sampling resistor. The two ends of the inductor are respectively connected to the SW1 pin and the SW2 pin. The DC-DC converter chip outputs a control signal to the PD protocol chip through I2C communication. Specifically, the SCL terminal and the SDL terminal of the DC-DC converter chip are respectively connected to the SCL terminal and the SDL terminal of the PD protocol chip.

[0059] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all such improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A charging circuit for automatically compensating for line loss of a PD, characterized in that: The device comprises a Type C interface (1), a PD protocol chip (2) and a PD power conversion module (3); the voltage input end of the Type C interface (1) is connected to the voltage output end of the PD power conversion module (3), the voltage input end of the PD power conversion module (3) is connected to an external power supply, the control signal input end of the PD power conversion module (3) is connected to the control signal output end of the PD protocol chip (2), and the CC signal connection end of the PD protocol chip (2) is connected to the CC signal connection end of the Type C interface (1); the PD charging circuit that automatically compensates for line loss is connected to a device to be charged via the Type C interface (1), wherein: The PD protocol chip (2) is used to determine the required voltage of the powered device and control the PD power conversion module (3) to convert the input voltage Vin into the required voltage of the powered device; The PD power conversion module (3) is used to convert the input voltage Vin and output the converted voltage VBUS after filtering, and is also used to sample the current of the output current path and dynamically adjust the converted voltage VBUS according to the sampled current so that the post-line output voltage Vo reaches the required voltage value of the powered device; The TYPE C interface is used to provide the line output voltage Vo formed by the converted voltage VBUS passing through the wire to the powered device; The PD power conversion module (3) includes a DC-DC conversion chip (31), a switch circuit (32), a filter circuit (33) and a sampling resistor R1, wherein the input end of the switch circuit (32) is connected to the power supply, the output end is connected to the input end of the filter circuit (33), and the control end is connected to the DC-DC conversion chip (31). The output end of the filter circuit (33) is connected to the positive input end of the sampling resistor R1, and the negative input end of the sampling resistor R1 is connected to the Type C interface (1); The DC-DC conversion chip (31) is provided with a PWM control unit (311), a driving unit (312) and a current detection amplifier unit (313); the PWM control unit (311) and the current detection amplifier unit (313) are connected; both ends of the sampling resistor R1 are connected to the current detection amplifier unit (313); the switch circuit (32) includes a power switch tube K1, or the switch circuit (32) includes a first MOS tube U48, a second MOS tube U49, a third MOS tube U50 and a fourth MOS tube U51; The gates of the first MOS transistor U48, the second MOS transistor U49, the third MOS transistor U50, and the fourth MOS transistor U51 are respectively connected to the HD1, HD2, LD1, and LD2 pins of the DC-DC converter chip. The drain of the first MOS transistor U48 is connected to the power supply, and the source is connected to the drain of the third MOS transistor U50. The source of the third MOS transistor U50 is connected to the source of the fourth MOS transistor U51. The drain of the fourth MOS transistor U51 is connected to the source of the second MOS transistor U49. The drain of the second MOS transistor U49 is connected to the positive input terminal of the sampling resistor. The two ends of the inductor are respectively connected to the SW1 pin and the SW2 pin. The DC-DC converter chip outputs a control signal to the PD protocol chip through I2C communication. The SCL and SDL terminals of the DC-DC converter chip are respectively connected to the SCL and SDL terminals of the PD protocol chip. The PWM control unit (311) outputs a switch drive signal, which is input to a drive unit (312). The output end of the drive unit (312) is connected to the control end of the power switch tube K1. The drive unit (312) controls the on and off of the power switch tube K1 according to the switch drive signal output by the PWM control module. The PWM control unit (311) is connected to the output end of the current detection amplifier unit, and is used to receive the sampled current sent by the current detection amplifier unit, generate a PWM control signal according to the sampled current control, and send the PWM control signal to the drive unit (312) through the PWM end, wherein the PWM control signal has a predetermined duty cycle; the control end of the drive unit (312) is connected to the PWM end of the PWM control unit (311), the input end of the PWM control unit (311) is connected to the power input end, and the output end of the drive unit (312) is connected to the power switch tube K1; the drive unit (312) and the power switch tube K1 are used to receive the PWM control signal, and adjust the duty cycle of the conduction time of their input end and output end according to the PWM control signal to adjust the output voltage.

2. The PD charging circuit with automatic line loss compensation according to claim 1, characterized in that: The filter circuit (33) includes an inductor L, a first capacitor C1, and a second capacitor C2. One end of each of the inductor, the first capacitor C1, and the second capacitor C2 is connected to the positive input end of the sampling resistor R1. The negative input end of the sampling resistor R1 is connected to the Type C interface (1). The other end of the inductor is connected to the switching circuit (32). The other ends of the first capacitor C1 and the second capacitor C2 are grounded.

3. The PD charging circuit with automatic line loss compensation according to claim 1, characterized in that: The power switch tube K1 is a PMOS tube or an NMOS tube, the gate of the power switch tube K1 is connected to the PWM control unit (311), the source is connected to the power supply, and the drain is connected to the filter circuit (33).

4. A PD charging method with automatic line loss compensation, based on the PD charging circuit with automatic line loss compensation according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1: The PD protocol chip (2) detects that the TYPE C interface (1) is connected to the powered device, and then performs standard PD protocol communication with the powered device to identify the voltage requirement of the powered device; Step 2: The PD protocol chip (2) inputs the control signal into the DC-DC conversion chip (31), and the DC-DC conversion chip (31) performs voltage conversion on the input voltage Vin according to the control signal, and outputs the conversion voltage VBUS after filtering by the filter circuit (33); Step 3: The DC-DC conversion chip (31) detects the current value of the output current Io in real time through the current detection amplifier unit (313) to determine whether the current value is within a preset range. If the current value is within the preset range, step 4 is executed; if the current value is not within the preset range, step 5 is executed. Step 4: Determine the preset range of the current value, and adjust the voltage of the conversion voltage VBUS to a voltage corresponding to the preset current range; Step 5: The converted voltage VBUS is converted into a line output voltage Vo that meets the requirements of the powered device after passing through the wire, and the line output voltage Vo is output to the TYPE C interface.

5. The PD charging method with automatic compensation for line loss according to claim 4, characterized in that: The register in the DC-DC conversion chip (31) is preset with multiple current intervals corresponding to the voltage required by the device and optimal output voltage values ​​corresponding to the multiple current intervals. The PWM control unit (311) controls the power switch tube K1 to convert the voltage of the conversion voltage VBUS into the optimal output voltage value.

6. The PD charging method with automatic line loss compensation according to claim 4, characterized in that: In step 2, the value of the converted voltage VBUS is the voltage value required by the powered device. In step 4, the value of the converted voltage VBUS is not higher than 105% of the required voltage value.

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