WO2021082731A1

WO2021082731A1 - Electronic device and reverse charging method

Info

Publication number: WO2021082731A1
Application number: PCT/CN2020/113319
Authority: WO
Inventors: 李成亚; 马鹏飞; 栗忠明
Original assignee: 华为技术有限公司
Priority date: 2019-10-31
Filing date: 2020-09-03
Publication date: 2021-05-06
Also published as: CN110829523A; CN110829523B

Abstract

Provided are an electronic device and a reverse charging method. The electronic device may be a terminal device that supports a reverse charging function. A pull-up circuit is integrated on the electronic device provided in the embodiments of the present application, such that the electronic device can provide a first voltage to a DM pin of a USB interface after accessing a master device end of a USB OTG line, so that a slave device can identify a USB interface of the electronic device as a CDP. Therefore, the electronic device provided in the embodiments of the present application can provide a relatively large charging current for the slave device on the basis of a CDP protocol.

Description

Electronic equipment and reverse charging method

Cross-references to related applications

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office on October 31, 2019, the application number is 201911054726.2, and the application name is "an electronic device and reverse charging method", the entire content of which is incorporated herein by reference Applying.

Technical field

This application relates to the field of reverse charging technology, and in particular to an electronic device and a reverse charging method.

Background technique

With the development of the electronic market, more and more electronic devices are equipped with a reverse charging function. For an electronic device (such as a mobile phone) with a reverse charging function, it can charge another electronic device (such as a tablet computer) via a universal serial bus (USB) movable (on the go, OTG) cable. Among them, the electronic device that provides charging can be used as a host device, and the electronic device that is charged can be used as a slave device (device).

Specifically, in the current OTG charging process, the USB OTG cable includes a master device end (end A) and a slave device end (end B). The A end of the USB OTG line is connected to the USB interface of the master device, and the B end of the USB OTG line is connected to the USB interface of the slave device. After the master device determines that it is connected to end A of the USB OTG line, it can provide charging power to the slave device through the USB OTG line. After the slave device determines to connect to the B end of the USB OTG line, it can recognize the USB interface of the master device as a standard downstream port (SDP) through the USB OTG line, and then receive the charging provided by the master device based on the SDP protocol Electrical energy.

However, the SDP protocol stipulates that the maximum charging current is 500mA, so the slave device will limit the charging current to 500mA, resulting in a lower reverse charging speed. Therefore, the existing reverse charging technology needs to be further studied.

Summary of the invention

In view of this, this application provides an electronic device and a reverse charging method that integrates a pull-up circuit in the electronic device, so that the electronic device can connect to the main device end of the USB OTG line through the DM pin of the USB interface The first voltage is provided so that the slave device can recognize the USB interface of the electronic device as a CDP port. Furthermore, it can realize high-current reverse charging based on the CDP protocol.

In the first aspect, an embodiment of the present application provides an electronic device, which includes: a universal serial bus USB interface, a pull-up circuit, and a control circuit; wherein the USB interface is a standard downstream port SDP, and the pull-up circuit in the electronic device They are respectively coupled with the digital negative DM pin of the USB interface and the control circuit; the control circuit is used to control the pull-up circuit to provide the first DM pin to the DM pin after determining that the USB interface is connected to the main device end of the USB movable OTG line Voltage, the first voltage is used to indicate that the USB interface is a charging downstream port CDP.

After the master device and the slave device are connected through the USB OTG line, the DM pin of the USB interface of the master device can be coupled with the DM pin of the USB interface of the slave device through the USB OTG line, and the DP pin of the USB interface of the master device can pass through The USB OTG line is coupled with the DP pin of the USB interface of the slave device. The slave device can execute the BC1.2 protocol, and identify the type of the USB interface of the master device through the voltage change of the DM pin of the USB interface and the voltage change of the DP pin. Specifically, the slave device will apply the DP voltage to the DP pin of its USB interface. If the voltage of the DM pin of its USB interface is not pulled up accordingly, the slave device can determine that the USB interface of the master device is an SDP interface. Conversely, if the voltage of the DM pin in the USB interface of the slave device is pulled up, the slave device will apply the DM voltage to the DM pin. If the voltage of the DP pin is pulled up, the slave device It can be determined that the USB interface of the master device is a DCP port. On the contrary, if the DP pin in the USB interface of the slave device is not pulled up accordingly, the slave device can determine that the USB interface of the master device is a CDP port.

In the embodiment of the present application, after determining the main device terminal connected to the USB OTG line, the control circuit controls the pull-up circuit to provide the first voltage to the DM pin. The slave device end of the USB OTG line is connected to the USB interface of the slave device. Since the DM pin of the master device is applied with the first voltage, the voltage of the DM pin of the slave device is pulled up accordingly. Furthermore, when the slave device recognizes the USB interface of the master device, after applying the DP voltage to the DP pin, the slave device can detect that the voltage of the DM pin of its USB interface is pulled up, so the slave device will not transfer the master device The USB interface is recognized as an SDP port. The slave device instead applies the DM voltage to the DM pin. Since the USB interface of the electronic device is actually an SDP port, the voltage of the DP pin of the slave device will not be pulled up accordingly, so that the slave device can connect the master device The USB interface is recognized as a CDP port, and then large current reverse charging can be realized based on the CDP protocol.

In the embodiment of the present application, the control circuit can determine whether the USB interface is connected to the main device end of the USB OTG line at least in the following two ways:

In a possible implementation manner, the electronic device further includes a power management circuit coupled to the trigger pin of the USB interface of the electronic device; the power management circuit can detect that the voltage of the trigger pin is lower than the first threshold After the voltage is applied, the first detection signal is sent to the control circuit; after receiving the first detection signal, the control circuit may determine that the USB interface is connected to the main device end of the USB OTG line.

Among them, the trigger pin of the USB interface is determined by the specific type of the USB interface. For example, the trigger pin in the USB 2.0 interface may be an identification (ID) pin, and for example, the trigger pin in the USB Type-C interface may be a configuration channel (configuration channel, CC) pin.

In another possible implementation, the control circuit is also coupled with the trigger pin of the USB interface; the control circuit can also determine that the USB interface is connected to the USB OTG line after detecting that the voltage of the trigger pin is lower than the first threshold voltage The main equipment side.

In a possible implementation manner, the electronic device further includes a charging management circuit, which is coupled to the VBUS pin of the USB interface; the control circuit can also control the USB port after it is connected to the main device end of the USB OTG line The charging management circuit outputs the charging voltage to the VBUS pin of the USB interface. Controlling the charging management circuit to output the charging voltage to the VBUS pin of the USB interface can cause the voltage of the VBUS pin of the slave device to be pulled up accordingly, so that the slave device can recognize the slave device connected to the USB OTG line.

In the embodiment of the present application, the control circuit can more accurately control the time when the pull-up circuit outputs the first voltage in at least the following two ways:

In a possible implementation manner, the control circuit may turn on the DP comparator for executing the BC1.2 protocol after the time for controlling the charging management circuit to output the charging voltage to the VBUS pin of the USB interface reaches the first time delay; After receiving the third detection signal provided by the DP comparator, the pull-up circuit is controlled to provide the first voltage to the DM pin.

Specifically, in the process of identifying the type of the USB interface of the master device, the slave device applies a DP voltage to the DP pin of the slave device, and identifies the type of the USB interface of the master device through the voltage change of the DM pin of the slave device. In the embodiment of the present application, after the control circuit receives the third detection signal provided by the DP comparator, it indicates that the voltage of the DP pin of the electronic device (master device) is pulled up. At this time, the pull-up circuit is turned on to become the master device. The DM pin provides the first voltage, so that the slave device can detect that the voltage of the DM pin of the slave device is pulled up, which can not only prevent the slave device from recognizing the USB interface of the master device as an SDP port, but also can control it more accurately. The time for the pull circuit to output the first voltage.

In another possible implementation, the control circuit can detect the voltage of the digital positive DP pin of the USB interface after determining that the USB interface is connected to the main device end of the USB OTG line; after detecting that the voltage of the DP pin is greater than the first After the three threshold voltages, the pull-up circuit is controlled to provide the first voltage to the DM pin.

In a possible implementation manner, the control circuit may also control the pull-up circuit to stop providing the first voltage to the DM pin after the time for controlling the pull-up circuit to provide the first voltage to the DM pin reaches the second time delay. In the embodiment of the present application, the duration of the second delay can be determined according to the BC 1.2 protocol. For example, after the slave device applies the DP voltage to the DP pin, and then applies the DM voltage to the DM pin after an interval of 40ms, the second delay in the embodiment of this application is not less than 40ms to ensure that the slave device can apply the DP pin to the DP pin. After the DP voltage, it can be detected that the voltage of the DM pin of the slave device is pulled up accordingly.

In the embodiments of the present application, there are multiple possible implementations of the pull-up circuit, for example:

In a possible implementation, the pull-up circuit includes a first switch tube and a first resistor; wherein, the control electrode of the first switch tube is coupled to the control circuit, and the first electrode of the first switch tube is connected to one end of the first resistor. Coupling, the second electrode of the first switch tube is coupled with the DM pin, and the other end of the first resistor is used to receive the basic voltage; the control circuit can turn on the first terminal after confirming that the USB interface is connected to the main device end of the USB OTG line turning tube.

Exemplarily, the above-mentioned pull-up circuit may further include a second resistor, one end of the second resistor is coupled with the control circuit, and the other end of the second resistor is coupled with the control electrode of the first switch tube.

Exemplarily, the above-mentioned first switch tube may be a bipolar transistor or a field effect transistor.

Exemplarily, the above-mentioned basic voltage may be a voltage provided by a control circuit or a power management circuit for the pull-up circuit.

In another possible implementation, the pull-up circuit includes a third resistor; one end of the third resistor is coupled to the control circuit, and the other end of the third resistor is coupled to the DM pin; the control circuit can determine whether the USB interface is connected After the main device end of the USB OTG line, it outputs the basic voltage to the third resistor.

In the second aspect, the embodiments of the present application provide a reverse charging method, which can be applied to a control circuit, the control circuit is coupled with a pull-up circuit, and the pull-up circuit is connected to the digital negative DM pin of the universal serial bus USB interface The type of the USB interface is a standard downstream port SDP; the reverse charging method provided in the embodiment of the present application includes: after determining that the USB interface is connected to the main device end of the USB movable OTG line, control the pull-up circuit to lead to the DM The pin provides a first voltage, where the first voltage is used to indicate that the USB interface is a charging downstream port CDP.

In a possible implementation, the control circuit is also coupled with the power management circuit, and the power management circuit is coupled with the trigger pin of the USB interface; the power management circuit is used to detect that the voltage of the trigger pin is lower than the first threshold voltage Then, the first detection signal is sent to the control circuit; the reverse charging method provided in the embodiment of the present application further includes: after receiving the first detection signal, determining that the USB interface is connected to the main device end of the USB OTG line.

In a possible implementation manner, the control circuit is also coupled with the trigger pin of the USB interface; the reverse charging method provided in the embodiment of the present application further includes: after detecting that the trigger pin is lower than the first threshold voltage, Make sure that the USB interface is connected to the main device end of the USB OTG line.

In a possible implementation, the control circuit is also coupled with the charging management circuit, and the charging management circuit is coupled with the VBUS pin of the USB interface; after determining that the USB interface is connected to the main device end of the USB OTG line, it also includes: controlling charging The management circuit outputs the charging voltage to the VBUS pin of the USB interface.

In a possible implementation manner, after it is determined that the USB interface is connected to the main device end of the USB movable OTG line, the pull-up circuit is controlled to provide a first voltage to the DM pin, and the first voltage is used to indicate that the USB interface is The charging downstream port CDP includes: after the time for controlling the charging management circuit to output the charging voltage to the VBUS pin of the USB interface reaches the first time delay, turning on the DP comparator for executing the BC1.2 protocol; after receiving the DP comparator After the third detection signal is provided, the pull-up circuit is controlled to provide the first voltage to the DM pin.

In a possible implementation, after determining that the USB interface is connected to the main device end of the USB OTG line, the pull-up circuit is controlled to provide the first voltage to the DM pin, and the first voltage is used to indicate that the USB interface is a charging downstream port CDP , Including: after determining that the USB interface is connected to the main device end of the USB OTG line, detecting the voltage of the digital positive DP pin of the USB interface; after detecting that the voltage of the DP pin is greater than the third threshold voltage, controlling the pull-up circuit to The DM pin provides the first voltage.

In a possible implementation manner, after controlling the pull-up circuit to provide the first voltage to the DM pin, the method further includes: controlling the pull-up circuit to provide the first voltage to the DM pin after the second time delay reaches the second time delay, controlling the pull-up circuit to provide the first voltage to the DM pin. The pull circuit stops supplying the first voltage to the DM pin.

In a possible implementation, the pull-up circuit includes a first switch tube and a first resistor; the control electrode of the first switch tube is coupled with the control circuit, and the first electrode of the first switch tube is coupled with one end of the first resistor, The second electrode of the first switch tube is coupled to the DM pin, and the other end of the first resistor is used to receive the basic voltage; after confirming that the USB interface is connected to the main device end of the USB OTG line, the pull-up circuit is controlled to provide the DM pin The first voltage includes: after it is determined that the USB interface is connected to the main device end of the USB OTG line, the first switch tube is turned on.

In a possible implementation manner, the pull-up circuit further includes a second resistor, one end of the second resistor is coupled to the control circuit, and the other end of the second resistor is coupled to the control electrode of the first switch tube.

In a possible implementation manner, the first switch tube is a bipolar transistor or a field effect transistor.

In a possible implementation manner, the base voltage is the voltage provided by the control circuit or the power management circuit for the pull-up circuit.

In a possible implementation, the pull-up circuit includes a third resistor; one end of the third resistor is coupled to the control circuit, and the other end of the third resistor is coupled to the DM pin; after determining that the USB interface is connected to the main USB OTG line After the device end, controlling the pull-up circuit to provide the first voltage to the DM pin includes: after determining that the USB interface is connected to the main device end of the USB OTG line, outputting the basic voltage to the third resistor.

These and other aspects of the present application will be more concise and understandable in the description of the following embodiments.

Description of the drawings

FIG. 1 is a schematic diagram of a reverse charging applicable to an embodiment of this application;

FIG. 2 is a schematic diagram of the structure of an electronic device to which an embodiment of the application is applicable;

FIG. 3 is a schematic flow chart of a slave device identifying the USB interface of the master device;

4 is a schematic structural diagram of a pull-up circuit provided by an embodiment of the application;

FIG. 5 is a schematic structural diagram of a pull-up circuit provided by an embodiment of the application;

FIG. 6 is a schematic structural diagram of a pull-up circuit provided by an embodiment of the application;

FIG. 7 is a schematic flowchart of a reverse charging method provided by an embodiment of the application.

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

In order to make the purpose, technical solutions, and advantages of the application more clear, the application will be further described in detail below with reference to the accompanying drawings. The specific operation method in the method embodiment can also be applied to the device embodiment or the system embodiment. It should be noted that in the description of this application, "at least one" refers to one or more, and multiple refers to two or more. In view of this, in the embodiments of the present invention, “a plurality of” may also be understood as “at least two”. "And/or" describes the association relationship of the associated objects, indicating that there can be three types of relationships, for example, A and/or B, which can mean: A alone exists, A and B exist at the same time, and B exists alone. In addition, the character "/", unless otherwise specified, generally indicates that the associated objects before and after are in an "or" relationship. In addition, it should be understood that in the description of this application, words such as "first" and "second" are only used for the purpose of distinguishing description, and cannot be understood as indicating or implying relative importance, nor can it be understood as indicating Or imply the order.

It should be pointed out that “coupling” in the embodiments of this application refers to the energy transfer relationship. For example, the coupling of A and B means that energy can be transferred between A and B. There are many possibilities for specific forms of energy. For example, electric energy, magnetic field potential energy, etc. When electric energy can be transferred between A and B, it is reflected in the circuit connection relationship, that is, A and B can be directly electrically connected, or indirectly electrically connected through other conductors or circuit elements.

It should be pointed out that “access” in the embodiment of this application refers to the realization of a coupling connection between the two interfaces, and the corresponding pins of the two interfaces are coupled one by one. The specific coupling and connection methods are not limited. For example, the coupling connection may be insertion, docking, and so on. Taking insertion as an example, the interface 1 is connected to the interface 2. It can be that the interface 1 is inserted into the interface 2, or the interface 2 is inserted into the interface 1.

At present, the application of reverse charging technology in electronic devices is becoming more and more mature. The so-called reverse charging means that an electronic device can use the electric energy stored in its own battery to charge another electronic device. Generally speaking, the current reverse charging is mostly in a wired form, that is, a USB movable (on the go, OTG) cable is needed to realize reverse charging. Exemplarily, as shown in FIG. 1, the USB OTG line 300 mainly includes an A terminal and a B terminal. Before performing reverse charging, the user can connect the A terminal of the USB OTG cable 300 to the USB interface 101 of the electronic device 100, and connect the B terminal of the USB OTG cable 300 to the USB interface 201 of the electronic device 200. The electronic device 100 can output electric energy from the USB interface 101 to the A end of the USB OTG line, and the electric energy received by the A end of the USB OTG line is transmitted to the B end of the USB OTG line, and is input to the electronic device 200 through the USB interface 201. The electronic device 200 can then use the power input from the USB interface 201 to operate or charge.

It should be pointed out that the shape of the USB OTG line 300 in the embodiment of the present application may be linear, or a non-linear shape such as a square or a circle, and the embodiment of the present application does not limit the shape of the USB OTG line 300.

For ease of description, the electronic device 100 is taken as an example to further describe the electronic device to which the embodiments of the present application are applied. FIG. 2 exemplarily shows the structure of the electronic device to which the embodiment of the present application is applicable. The electronic device may be an electronic device such as a smart phone or a tablet computer that supports reverse charging. As shown in FIG. 2, the electronic device 100 mainly includes a universal serial bus USB interface 101, a control circuit 102, a power management circuit 103, a battery 104, and a charging management circuit 106.

It can be understood that the structure illustrated in the embodiment of the present application does not constitute a specific limitation on the electronic device 100. In other embodiments of the present application, the electronic device 100 may include more or fewer components than those shown in FIG. 2, or combine certain components, or split certain components, or arrange different components. The components shown in Figure 2 can be implemented in hardware, software or a combination of software and hardware. For example, the electronic device 100 may also include a central processing unit, an external memory interface, an internal memory, an antenna, a mobile communication module, a wireless communication module, an audio module, a speaker, a receiver, a microphone, a headphone jack, a sensor module, buttons, a motor, and an indicator , Camera, display, and subscriber identification module (SIM) card interface, etc. Among them, the sensor module may include a pressure sensor, a gyroscope sensor, an air pressure sensor, a magnetic sensor, an acceleration sensor, a distance sensor, a proximity light sensor, a fingerprint sensor, a temperature sensor, a touch sensor, an ambient light sensor, a bone conduction sensor, etc.

The control circuit 102 may include one or more processing units, which may be a central processing unit (CPU) of the electronic device 100 or a system on chip (SOC) of the electronic device 100. Exemplary: the control circuit 102 may include an application processor (application processor, AP), a controller, a memory, a digital signal processor (digital signal processor, DSP), and so on. Among them, the different processing units may be independent devices or integrated in one or more processors.

The controller may be the nerve center and command center of the electronic device 100. The controller can generate control signals according to the instruction operation code and timing signals. Exemplarily, the controller in the control circuit 102 in the embodiment of the present application can generate a control signal, and the control circuit 102 can control the operation of the power management circuit 103 and the USB interface 101 through the control signal.

A memory can also be provided in the control circuit 102 for storing instructions and data. In some embodiments, the memory in the control circuit 102 is a cache memory. The memory can store instructions or data that the control circuit 102 has just used or used cyclically. If the control circuit 102 needs to use the instruction or data again, it can be directly called from the memory. Repeated accesses are avoided, the waiting time of the processor 110 is reduced, and the efficiency of the system is improved.

In some embodiments, the control circuit 102 may include one or more interfaces. The interface may include a control bus interface, a general-purpose input/output (GPIO) interface, and the like.

Among them, the control bus interface may be an integrated circuit (inter-integrated circuit, I2C) interface, a serial peripheral interface (serial peripheral interface, SPI), a system power management interface (system power management interface, SPMI), etc. The embodiments of this application There are not many restrictions on this. In the embodiment of the present application, the control circuit 102 may couple the power management circuit 103 and the charging management circuit 106 through a control bus interface to realize the reverse charging function of the electronic device 100.

The GPIO interface can be configured through software. The GPIO interface can be configured as a control signal interface, can also be configured as a data signal interface, and can also be configured as a power supply interface. In some embodiments, the GPIO interface can be used to connect the control circuit 102 with other circuit structures in the electronic device 100, and the GPIO interface can be flexibly configured according to the type of the connected circuit structure.

The power management circuit 103 may be a power management unit (power management unit, PMU), and an integrated power management circuit (power management IC, PMIC). The power management circuit 103 can receive electric energy provided by the battery 104 and/or the charging management circuit 106 to supply power to the control circuit 102 and other circuit structures in the electronic device. The power management circuit 103 can also be used to monitor battery capacity, battery cycle times, battery health status (leakage, impedance) and other parameters. In addition, the power management circuit 103 can also detect the voltage of each pin in the USB interface, and send a detection signal to the control circuit 102 when the voltage state of each pin changes. In some other embodiments, the power management circuit 103 and the control circuit 102 may also be integrated in the same chip.

A charging management circuit (charger IC) 106 may receive charging power through the USB interface 101, and store the received charging power in the battery 104. While the charging management circuit 106 is charging the battery 104, it can also supply power to the power management circuit 103, so that the power management circuit 103 can simultaneously supply power to other circuit structures in the electronic device. When the electronic device is used as the main device in wireless charging, the control circuit 102 can control the charging management circuit 106 to output a charging voltage to the USB interface 101, and the charging voltage is generally 5V.

The USB interface 101 is an interface that complies with the USB standard specifications, and specifically can be a Micro USB interface, a USB Type C interface, and so on. The USB interface 101 can be used to connect a charger to charge the electronic device 100, and can also be used to connect the electronic device 100 to the A terminal of the USB OTG cable 300, so that the electronic device 100 can charge other electronic devices.

Exemplarily, the USB interface 101 mainly includes a ground (GND) pin, a trigger pin, a data positive (DP) pin, a data negative (DM) pin, and a power supply bus (VBUS) pin. Among them, the DP pin can also be referred to as the D+ pin, and the DM pin can also be referred to as the D- pin. The trigger pin can trigger the control circuit 102 to determine that the USB interface 101 is connected to the main device end of the USB OTG line 300 (end A of the USB OTG line 300). Exemplarily, for conventional USB interfaces such as Micro USB interface and USB Type C, the trigger pin may be the identification (ID) pin of the Micro USB interface, and for the USB Type C interface, the trigger pin may be control (CC) Pin. The specific implementation of the trigger pin is determined by the specific type of the USB interface 101 and the specific identification logic inside the control circuit 102, which is not limited in the embodiment of the present application. For ease of understanding, the embodiment of the present application uses the ID pin as the trigger pin in the following to exemplarily further illustrate the embodiment of the present application.

In the USB interface 101, the GND pin is coupled with the ground circuit and is maintained at a zero potential state. The ID pin is applied with a stable pull-up voltage by the power management circuit 103, and the voltage value of the pull-up voltage is generally 1.8V.

The VBUS pin is coupled with the power management circuit 103. During the charging process, the VBUS pin can receive the charging power input by the charger or other electronic devices, and provide the received charging power to the charging management circuit 106. During the reverse charging process, the VBUS pin can receive and output the electric energy provided by the charging management circuit 106.

In the USB interface 101, the ID pin can be used to trigger the control circuit 102 to determine that the USB interface 101 is connected to the host device end of the USB OTG line 300 (end A of the USB OTG line 300). in particular:

Both ends A and B of the USB OTG line 300 can be understood as different types of USB interfaces. The A end and the B end of the USB OTG line 300 respectively have pins adapted to the USB interface 101 of the electronic device 100. Specifically, when end A of the USB OTG cable 300 is connected to the USB interface 101, the GND pin of the A end is coupled to the GND pin of the USB interface 101, and the ID pin of the A end is coupled to the ID pin of the USB interface 101 , The DP pin of the A terminal is coupled with the DP pin of the USB interface 101, the DM pin of the A terminal is coupled with the DM pin of the USB interface 101, and the VBUS pin of the A terminal is coupled with the VBUS pin of the USB interface. The same is true for the B side, so I won't repeat it here.

The difference between the A terminal and the B terminal of the USB OTG line 300 is that the ID pin of the A terminal is coupled with the ground circuit, while the ID pin of the B terminal is left floating. When end A of the USB OTG line 300 is connected to the USB interface 101 of the electronic device 100, the ID pin of the USB interface 101 is grounded through the ID pin of the end A of the USB OTG line 300, so the ID pin of the USB interface 101 The voltage is pulled down accordingly. In an embodiment of the present application, when the voltage of the ID pin of the USB interface 101 is pulled down to be less than the first threshold voltage, it can be considered that the USB interface 101 is connected to the A terminal of the USB OTG line 300. Generally, the USB interface 101 The voltage of the ID pin will be pulled down to 0V.

After the B end of the USB OTG line 300 is connected to the USB interface 101 of the electronic device 100, the ID pin of the USB interface 101 is coupled with the ID pin of the B end. Since the ID pin of the B terminal is suspended, the voltage of the ID pin of the USB interface 101 can still be maintained at 1.8V.

In view of this, the control circuit 102 in the embodiment of the present application can determine that the USB interface 101 is connected to the A terminal of the USB OTG line 300 through at least the following two possible implementation manners:

Method 1: The power management circuit 103 can detect the voltage of the ID pin in the USB interface 101. When the voltage of the ID pin is detected to be pulled down, that is, after the voltage of the ID pin is detected to be lower than the first threshold voltage, the power management circuit 103 sends the first detection signal to the control circuit 102. Exemplarily, the power management circuit 103 may send a first detection signal to the control circuit 102 through the control bus, and the first detection signal may indicate to the control circuit 102 that the USB interface 101 is connected to the A terminal of the USB OTG line 300. After receiving the first detection signal, the control circuit 102 can determine according to the first detection signal that the USB interface 101 is connected to end A of the USB OTG line 300, and can then determine that the electronic device belongs to the main device, and continue to implement the battery charging specification (battery charging specification, BC) 1.2 protocol, complete the handshake with the slave device.

Manner 2: The control circuit 102 is coupled with the ID pin, and the control circuit 102 can detect the voltage of the ID pin. When detecting that the voltage of the ID pin is pulled down, that is, after detecting that the voltage of the ID pin is lower than the first threshold voltage, the control circuit 102 can determine that the USB interface 101 is connected to the A terminal of the USB OTG line 300, and the control circuit 102 can then determine that the electronic device belongs to as the master device, and continue to execute the 1.2 protocol to complete the handshake with the slave device.

In the charging scenario shown in Figure 1, the electronic device 100 is connected to end A of the USB OTG line 300, so the electronic device 100 is the master device, and the electronic device 200 is connected to the end B of the USB OTG line 300, so the electronic device 200 is the slave equipment. It should be pointed out that the structure of the electronic device 200 is similar to that of the electronic device 100. The electronic device 200 includes a USB interface 201, a control circuit 202, a power management circuit 203, and a battery 204. The connection relationship between the various circuit structures can be referred to as shown in FIG. 2. As shown, this embodiment of the present application will not illustrate this with illustrations. For ease of description, the embodiment of the present application uses GND pin 1, ID pin 1, DP pin 1, DM pin 1, and VBUS pin 1 to represent the pins in the USB interface 101, and uses GND pin 2, ID pin 2, DP pin 2, DM pin 2, and VBUS pin 2 represent pins in the USB interface 201.

In the electronic device 100, the control circuit 102 can send a first control signal to the charging management circuit 106 after determining that the USB interface 101 is connected to the USB OTG line 300 end A, and the charging management circuit 106 receives the first control signal, The charging voltage is output to the VBUS pin 1 of the USB interface 101.

In the electronic device 200, the VBUS pin 2 of the USB interface 201 is coupled to the VBUS pin 1 of the USB interface 101 through the USB OTG line 300. Therefore, after the charging management circuit 106 outputs the charging voltage to the VBUS pin 1, the VBUS The voltage of pin 2 is pulled up accordingly. In a possible implementation, the power management circuit 203 can detect the voltage of the VBUS pin 2. When it is detected that the voltage of the VBUS pin 2 is pulled up, that is, after the voltage of the VBUS pin 2 is greater than the second threshold voltage, The second detection signal may be sent to the control circuit 202. Specifically, the power management circuit 203 may send a second detection signal to the control circuit 202 through the control bus, and the second detection signal may indicate to the control circuit 202 that the USB interface 202 is connected to the USB interface. After receiving the second detection signal, the control circuit 202 can determine that the USB interface 202 is connected to the USB interface according to the second detection signal. The control circuit 202 can then determine that the electronic device belongs to is a slave device, and continue to execute the 1.2 protocol to communicate with the master. The device completes the handshake.

In another possible implementation manner, the control circuit 202 is coupled to the VBUS pin 2. The control circuit 202 can detect the voltage of the VBUS pin 2. When it is detected that the voltage of the VBUS pin 2 is pulled up, that is, after the voltage of the VBUS pin 2 is greater than the second threshold voltage, the control circuit 202 can determine whether the USB interface 202 is connected. After entering the USB interface, the control circuit 202 can then determine that the electronic device belongs to is a slave device, and continue to execute the BC 1.2 protocol to complete the handshake with the master device.

It should be pointed out that the B end of the USB OTG line 300 is similar to a conventional USB interface, that is to say, after the B end of the USB OTG line 300 is connected to the electronic device 200, the control circuit 202 can only recognize that it is connected to the USB interface 201 For other USB interfaces, the electronic device to which the control circuit 202 belongs is a slave device by default, and the control circuit 202 does not identify which device's USB interface is connected to the USB interface 201. In other words, during the period when the electronic device 200 is a slave device, it can receive power through the USB OTG line 300 or through other USB data lines, which is similar to the application scenario of the USB interface in the existing electronic equipment. No longer.

Between the electronic device 100 and the electronic device 200, the handshake process based on the BC 1.2 protocol is mainly through the DP pin 1 and DM pin 1 in the USB interface 101, and the DP pin 2 and DM pin 2 in the USB interface 201 Achieved. Through the handshake process based on the BC 1.2 protocol, the electronic device 200 can recognize the type of the USB interface 101 of the electronic device 100.

Currently, according to the BC 1.2 protocol, there are mainly three types of USB interfaces: standard downstream port (strandard downstream port, SDP), dedicated charging port (DCP), and charge downstream port (CDP). At present, the USB ports of most electronic devices (such as smart phones and tablet computers) are SDP ports. The SDP protocol specifies a maximum charging current of 500 mA, so the SDP port cannot be used for high-current charging. The DCP port can provide greater charging current. Generally, the DCP port is used for special chargers such as wall charging. The CDP port also supports high-current charging, but the CDP port is mainly used as a port for computers, hubs (HUB) and other devices, and has not yet been widely used.

It should be pointed out that the interface type of the B end of the USB OTG line 300 is equivalent to the interface type of the USB interface 101. In other words, the USB OTG line 300 does not change the interface type of the USB interface 101, and the electronic device 200 can recognize the interface type of the USB interface 101 through the USB OTG line 300. For ease of presentation, the embodiment of the present application directly identifies the interface type of the USB interface 101 as an overview.

Next, taking FIG. 3 as an example, the process of identifying the USB interface 101 by the electronic device 200 will be further described. As shown in Figure 3, it mainly includes the following steps:

S301: The control circuit 202 turns on the DP voltage source and the DM current source in the power management circuit 203.

Exemplarily, the power management circuit 203 includes a DP current source, a DP voltage source, a DM current source, and a DM voltage source. Among them, the DP current source can limit the current transmitted by the DP pin 2 to not exceed the DP threshold current, the DP voltage source can output a constant DP voltage to the DP pin 2, and the DM current source can limit the current transmitted by the DM pin 2 to not exceed the DM Threshold current, DM voltage source can output a constant DM voltage to DM pin 2. Generally speaking, both the DP voltage and the DM voltage are 0.6V.

The control circuit 202 can send a control command to the power management circuit 203 through the control bus with the power management circuit 203, so as to turn on the DP voltage source and the DM current source in the power management circuit 203. It can be understood that during S301, the DM voltage source and the DP current source are turned off by default.

S302: The control circuit 202 detects the voltage of the DM pin 2. As shown in FIG. 2, the control circuit 202 is coupled to the DP pin 2 and the DM pin 2, and the control circuit 202 can directly detect the voltage of the DP pin 2 and the DM pin 2.

S303: If the voltage of the DM pin 2 is less than the fourth threshold voltage, execute S305 to determine that the USB interface 101 is an SDP port; otherwise, execute S304. Wherein, the fourth threshold voltage is not greater than the output voltages of the DP voltage source and the DM voltage source, and generally the fourth threshold voltage may be 0.35V.

The following is a brief description of the judgment principle:

As shown in Figure 2, the DP pin 1 of the SDP port (USB interface 101) is coupled to the ground circuit through a pull-down resistor RP, and the DM pin 1 is coupled to the ground circuit through a pull-down resistor RM. Discontinuous circuit. When the power management circuit 203 applies the DP voltage to the DP pin 2, the voltage of the DP pin 1 is pulled up accordingly. However, due to the open circuit between DP pin 1 and DM pin 1, DM pin 1 is still in a pull-down state, and the voltage of DM pin 2 will not be pulled up (generally, the voltage of DM pin 2 will remain at 0V) , So that the control circuit 202 can detect that the voltage of the DM pin 2 is less than the fourth threshold voltage.

Assuming that the USB interface 101 is a DCP port, the DP pin 1 and the DM pin 1 are short-circuited. When the power management circuit 203 applies the DP voltage to the DP pin 2, the voltage of the DP pin 1 is pulled up accordingly. Because DP pin 1 and DM pin 1 are short-circuited, the voltage of DM pin 1 is pulled up accordingly, and the voltage of DM pin 2 is pulled up accordingly, so the control circuit 202 can detect the DM pin The voltage of 2 is not less than the fourth threshold voltage.

Assuming that the USB interface 101 is a CDP port, the power management circuit 103 can detect the voltage of the DP pin 1. When the power management circuit 203 applies the DP voltage to the DP pin 2, the voltage of the DP pin 1 is pulled up accordingly. When the power management circuit 103 detects that the voltage of the DP pin 1 is greater than the reference voltage, the power management circuit 1 will turn on the DM voltage source to apply the DM voltage to the DM pin 1, and the voltage of the DM pin 2 will be pulled up accordingly. In turn, the control circuit 202 can detect that the voltage of the DM pin 2 is not less than the fourth threshold voltage.

It can be seen that only when the USB interface 101 is an SDP port, the control circuit 202 can detect that the voltage of the DM pin 2 is less than the fourth threshold voltage after the DP voltage source and the DM current source in the power management circuit 203 are turned on. Therefore, in S303, if the voltage of the DM pin 2 is less than the fourth threshold voltage, it can be determined that the USB interface 101 is an SDP port. When the USB interface 101 is a CDP port or a DCP port, after the DP voltage source and DM current source in the power management circuit 203 are turned on, the control circuit 202 will detect that the voltage of the DM pin 2 is not less than the fourth threshold voltage . Therefore, in S303, if the voltage of the DM pin 2 is not less than the fourth voltage threshold, S304 needs to be continued to further determine whether the USB interface 101 is a CDP port or a DCP port.

S304: The control circuit 202 turns on the DM voltage source and the DP current source in the power management circuit 203. It can be understood that it also includes turning off the DP voltage source and the DM current source in the power management circuit 203.

S306: The control circuit 202 detects the voltage of the DP pin 2.

S307: If the voltage of the DP pin 2 is less than the fifth threshold voltage, execute S308 to determine that the USB interface 101 is a CDP port. Otherwise, execute S309 to determine that the USB interface 101 is a DCP port.

Specifically, assuming that the USB interface 101 is a DCP port, the DP pin 1 and the DM pin 1 are short-circuited. Therefore, when the power management circuit 203 applies the DM voltage to the DM pin 2, the DP pin 1, DM pin 1 And the voltage of DP pin 2 is pulled up accordingly, so that the control circuit 202 can detect that the voltage of DP pin 2 is not less than the fifth threshold voltage. Generally speaking, the fifth threshold voltage can be the same as the fourth threshold voltage. The same, for example, both are 0.35V.

Assuming that the USB interface 101 is a CDP port, the DM pin 1 is grounded through the pull-down resistor RM, the DP pin 1 is grounded through the pull-down resistor RP, and the DM pin 1 and the DP pin 1 are open to each other. Therefore, when the power management circuit 203 applies the DM voltage to the DM pin 2, the voltages of the DP pin 1 and the DP pin 2 will not be pulled up accordingly, so that the control circuit 202 can detect the voltage of the DP pin 2. The voltage is less than the fifth threshold voltage.

Therefore, in the case that the USB interface 101 has been excluded as an SDP port, after the DM voltage source and the DP current source in the power management circuit 203 are turned on, if the voltage of the DP pin 2 is less than the fifth threshold voltage, it indicates that the USB interface 101 is For the CDP interface, if the voltage of the DP pin 2 is not less than the fifth threshold voltage, it indicates that the USB interface 101 is a DCP interface.

At present, in most electronic devices that support the reverse charging function, the USB interface is an SDP port. Therefore, when the slave device executes S303, it generally recognizes the USB interface of the master device as an SDP port, and then charges according to the SDP protocol. However, the SDP protocol stipulates that the charging current cannot exceed 500mA, which makes the current reverse charging speed slow. In view of this, the embodiment of this application improves the master device (electronic device 100). By adding a pull-up circuit 105 in the electronic device 100, the slave device (electronic device 200) can connect the electronic device to the electronic device according to the BC1.2 protocol. The USB interface 101 of 100 is identified as a CDP port, and the CDP protocol stipulates that the charging current can be 1.5-5A. Therefore, the technical solution provided by the embodiment of the present application is beneficial to achieve a large current reverse charging current, which is beneficial to improve The speed of reverse charging.

As shown in FIG. 2, the electronic device 100 further includes a pull-up circuit 105. The control terminal of the pull-up circuit 105 is coupled with the control circuit 102, and the output terminal of the pull-up circuit 105 is coupled with the power management circuit 103. The control circuit 102 may control the pull-up circuit 105 to provide the first voltage to the DM pin after determining that it is connected to the A terminal of the USB OTG line 300. For example, the first voltage may be 0.6V in this application. Among them, the pull-up circuit 105 can be provided in the electronic device 100 as an independent circuit structure, for example, fabricated on the main board of the electronic device 100. The pull-up circuit 105 can also be integrated with the control circuit 101 in the same chip, which is not limited in the embodiment of the present application.

Specifically, the control circuit 102 can control the pull-up circuit 105 to output the first voltage to the DP pin 1 through at least any one of the following three possible implementation manners:

In the first possible implementation manner, the control circuit 102 may immediately control the pull-up circuit 105 to provide the first voltage to the DM pin after determining that the USB interface 101 is connected to the A terminal of the USB OTG line 300.

In the second possible implementation manner, the control circuit 102 may detect the voltage of the DP pin 1 of the USB interface 101 after determining that the USB interface 101 is connected to the A terminal of the USB OTG line 300. When the control circuit 202 executes S301 to turn on the DP voltage source in the power management circuit 203, the DP pin 2 is applied with the DP voltage, and the voltage of the DP pin 1 will also be pulled up accordingly. Then, the control circuit 102 can detect that the voltage of the DP pin 1 is greater than the third threshold voltage. The control circuit 102 may turn on the pull-up circuit 105 after detecting that the voltage of the DP pin 1 is greater than the third threshold voltage. The control circuit 202 can still detect that the voltage of the DM pin 2 is pulled up, and continues to execute S304.

In a third possible implementation, the control circuit 102 controls the charging management circuit 106 to output the charging voltage to the VBUS pin 1 of the USB interface 101 after the first time delay reaches the first time delay, turning on the electronic device 100 for performing BC1. 2 protocol DP comparator.

During the first time delay, a continuous charging voltage is applied to the VBUS pin 1 of the USB interface 101. During this period, the electronic device 200 can recognize that an external USB interface is connected to the USB interface 201. Generally speaking, the first delay is related to the performance of the electronic device 200, and the first delay can be obtained by means of experiment, statistics, estimation, etc. The embodiments of the application do not limit this.

Regarding the DP comparator used to implement the BC1.2 protocol, the DP comparator may be located in the power management circuit 103 or the charging management circuit 106, which is not limited in the embodiment of the present application. The first input terminal of the DP comparator is coupled with the DP pin, the second input terminal of the DP comparator is maintained at the third threshold voltage, the output terminal of the DP comparator is coupled with the control circuit 102, and the DP comparator can be connected to the DP pin 1. When the voltage is greater than the third threshold voltage, a third detection signal is sent to the control circuit 102. Specifically, the DP comparator may send a third detection signal to the control circuit 102 through the control bus, and the third detection signal may indicate to the control circuit 102 that the voltage of the DP pin 1 is pulled up. After the control circuit 102 receives the third detection signal provided by the DP comparator, it can determine that the voltage of the DP pin 1 is pulled up according to the third detection signal. The control circuit 102 can further control the pull-up circuit 105 to provide the first voltage to the DM pin 1. After the time that the pull-up circuit 105 continues to provide the first voltage to the DM pin 1 reaches the second time delay, the control circuit 102 controls the pull-up circuit 105 to stop providing the first voltage to the DM pin 1.

During the second time delay, the electronic device 200 can complete the steps of detecting the voltage of the DM pin 2 and turning on the DM voltage source and the DP current source. According to the BC1.2 protocol, there is an interval of 40 ms between the time point when the electronic device 200 turns on the DP voltage source and the time point when the DM voltage source is turned on. Therefore, the second time delay in the embodiment of the present application is not less than 40 ms. After waiting for the second time delay, the control circuit 102 can control the pull-up circuit 105 to stop supplying the first voltage to the DM pin 1.

In the embodiment of the present application, since the DM pin 1 of the USB interface 101 is applied with the first voltage by the pull-up circuit 105, and the DM pin 1 of the USB interface 101 can pass through the USB OTG line 300 and the DM pin of the USB interface 201 2 is coupled, so the voltage of the DM pin 2 of the USB interface 201 will be pulled up accordingly. When the electronic device 200 executes S303, the control circuit 202 will detect that the voltage of the DM pin 2 of the USB interface 201 is not less than the fourth threshold Voltage, and then continue to execute S304. This prevents the electronic device 200 from recognizing the USB interface 101 as an SDP port.

In the embodiment of the present application, the USB interface 101 may actually be an SDP port, as shown in FIG. 2. Therefore, when the electronic device 200 executes S307, after the DM voltage source and the DP current source in the power management circuit 203 are turned on, the voltages of the DP pin 1 and the DP pin 2 will not be pulled up accordingly, so the control circuit 202 It can be detected that the voltage of the DP pin 2 is less than the fifth threshold voltage, so that the electronic device 200 can recognize the SDP port (USB interface 101) as a CDP port.

After that, the electronic device 200 can enumerate and charge the electronic device 100 according to the CDP protocol. Since the CDP protocol stipulates that the charging current can reach 1.5 to 5A, the electronic device 100 can use a larger charging current (up to 5A) Reverse charging is helpful to increase the speed of reverse charging.

In a possible implementation, after the electronic device 200 determines that the USB interface 101 of the electronic device 100 is a CDP port, it can also turn on the DP voltage source in the power management circuit 203 to apply the DP pin 2 of the USB interface 201 DP voltage. The DP pin 1 in the USB interface 101 is pulled up accordingly. In a possible implementation manner, the control circuit 101 may also detect the voltage of the DP pin 1 after determining that the USB interface 101 is connected to the A terminal of the USB OTG line 300. When the voltage of the DP pin 1 is greater than the third threshold voltage for the first time, it means that the control circuit 202 is performing S301. When the voltage of the DP pin 1 is greater than the third threshold voltage for the second time, it means that the control circuit 202 has completed identifying the USB interface 101. type. The control circuit 102 can then continue to perform the enumeration process and the reverse charging process after the enumeration process. Generally, the third threshold voltage and the fourth threshold voltage have the same value, for example, both can be 0.35V. The specific implementation of the enumeration process and the reverse charging process can refer to the existing protocol provisions, which will not be repeated.

In summary, the embodiments of the present application provide an electronic device. By setting a pull-up circuit in the electronic device, a pull-up voltage is applied to the DM pin of the USB interface of the master device, so that the slave device recognizes the USB interface of the master device. It is a CDP interface to increase the speed of reverse charging.

Next, with regard to the pull-up circuit 105 in the embodiment of the present application, the following specific embodiments are used for further description. In the embodiment of the present application, the pull-up circuit 105 has at least the following two possible implementation manners:

Realization method one

FIG. 4 exemplarily shows one of the implementation structures of the pull-up circuit 105 in the embodiment of the present application. As shown in FIG. 4, the pull-up circuit 105 includes a first switch S1 and a first resistor R1. Wherein, the control electrode of the first switch tube S1 is coupled with the control circuit 102, the first electrode of the first switch tube S1 is coupled with one end of the first resistor R1, and the second electrode of the first switch tube S1 is coupled with the DM pin 1. The other end of the first resistor R1 is used to receive the basic voltage.

Among them, the base voltage can be a voltage provided to conventional components in an electronic device, and is generally 1.8V. In the embodiment of the present application, as shown by the dashed line in FIG. 2, either the control circuit 102 may provide the basic voltage for the pull-up circuit 105, or the power management circuit 103 may provide the basic voltage for the pull-up circuit 105. This is not too restrictive.

In order to imitate the voltage state of the DM pin of the CDP port during the USB interface identification process, the pull-up circuit 105 in the embodiment of the present application can divide the basic voltage to obtain the first voltage, so that the first voltage applied to the DM pin 1 The voltage approaches the DM voltage output by the DM voltage source.

Exemplarily, one GPIO port in the control circuit 102 may be configured as a control port, and the first switch S1 is controlled to be turned on or off through the GPIO port, thereby controlling the operation of the pull-up circuit 105. The first switch S1 can be either a bipolar transistor as shown in FIG. 4 or a field effect transistor as shown in FIG. 5, which is not limited in the embodiment of the present application.

Specifically, after receiving the first detection signal, the control circuit 102 can turn on the first switch S1. After the first switch S1 is turned on, the first resistor R1, the first switch S1, and the grounding resistance RM of the DM pin 1 form a voltage divider circuit. After the basic voltage is divided by the first resistor R1 and the grounding resistor RM, the first One voltage. Among them, the first voltage satisfies the following formula 1:

Among them, V ₁ is the voltage value of the first voltage, r1 is the resistance value of the first resistor R1, rM is the resistance value of the grounding resistor RM, and V ₀ is the voltage value of the base voltage.

The control circuit 102 turns off the first switch S1, and can control the pull-up circuit 105 to stop applying the first voltage to the DM pin.

In a possible implementation manner, the pull-up circuit 105 may further include a second resistor R2. As shown in FIG. 4, one end of the second resistor R2 is coupled with the control circuit 102, and the other end of the second resistor R2 is coupled with the control electrode of the first switch S1. When the first switch S1 is a bipolar transistor, the second resistor R2 can reduce the current input to the control electrode (base) of the first switch S1, and the resistance of the first resistor R1 can be determined by the base current , Which makes the configuration of the first resistor R1 more convenient.

Exemplarily, assuming that the current input to the control electrode of the first switching tube S1 is 1 mA, and the amplification factor of the first switching tube S1 is 2, the current passing through the first resistor R1 can be obtained as 2 mA. Assuming that the base voltage is 1.8V, the first voltage is 0.6V, and the current of the control electrode is 1mA, the voltage drop between the first electrode and the second electrode in the first switch S1 is 0.3V, then the first resistance can be calculated R1 needs to generate a 0.9V voltage drop, and then according to the 2mA current passing through the first resistor R1, it can be calculated that the resistance of the first resistor R1 should be configured to be 150Ω.

Realization method two

FIG. 6 exemplarily shows another implementation structure of the pull-up circuit 105 in the embodiment of the present application. As shown in FIG. 6, the pull-up circuit 105 includes a third resistor R3, one end of the third resistor R3 is coupled to the control circuit 102, and the other end of the third resistor R3 is coupled to the DM pin 1. After receiving the first detection signal, the control circuit 102 outputs the basic voltage to the third resistor R3. After the control circuit 102 stops outputting the basic voltage to the third resistor R3, the third resistor R3 stops applying the first voltage to the DP pin 1.

In this implementation, the third resistor R3 and the ground resistor RM of the DM pin 1 can form a voltage divider circuit. When the control circuit 102 outputs the basic voltage to the third resistor R3, the basic voltage passes through the third resistor R3 and the ground resistor RM. After the voltage is divided, the first voltage is obtained, and the first voltage satisfies the above formula 1, which will not be repeated here.

In summary, the embodiment of the present application adds a pull-up circuit to the master device, and the pull-up circuit can apply the first voltage to the DM pin of the master device, so that the slave device can recognize the USB interface of the master device as a CDP port. In the embodiment of the present application, the pull-up circuit has a simple structure, is easy to implement, and is compatible with the existing USB 2.0 protocol and BC 1.2 protocol.

Based on the same technical concept, the embodiment of the present application also provides a reverse charging method. This method can be applied to the control circuit 102 shown in FIG. 2. FIG. 7 exemplarily shows a schematic flowchart of a reverse charging method provided by an embodiment of the present application. As shown in FIG. 7, it mainly includes:

S701: After determining that the USB interface 101 is connected to the main device end of the movable USB OTG line 300, control the pull-up circuit 105 to provide a first voltage to the DM pin 1. The first voltage is used to indicate that the USB interface is a charging downstream port CDP . For a specific implementation manner, reference may be made to the steps executed by the control circuit 101 in the foregoing embodiment, which will not be described in detail.

Wherein, the control circuit 102 can determine whether the USB interface 101 is connected to the main device end of the USB OTG line 300 by at least the following two methods:

In a possible implementation, the electronic device further includes a power management circuit 103, which is coupled to the trigger pin of the USB interface 101 of the electronic device; the power management circuit 103 can detect that the voltage of the trigger pin is low. After the first threshold voltage, the first detection signal is sent to the control circuit 102; the control circuit 102 may determine that the USB interface 101 is connected to the host device end of the USB OTG line 300 after receiving the first detection signal.

Among them, the trigger pin of the USB interface 101 is determined by the specific type of the USB interface 101. For example, the trigger pin in the Micro USB interface may be an ID pin, and for example, the trigger pin in the USB Type-C interface may be a CC pin.

In another possible implementation manner, the control circuit 102 is also coupled with the trigger pin of the USB interface 101; the control circuit 102 may also determine that the USB interface 101 is connected after detecting that the voltage of the trigger pin is lower than the first threshold voltage. Enter the main device end of the USB OTG line 300.

In a possible implementation, the electronic device further includes a charging management circuit 106, which is coupled to the VBUS pin of the USB interface 101; the control circuit 102 may also determine whether the USB interface 101 is connected to the USB OTG line 300 After the host device, the charging management circuit 106 is controlled to output the charging voltage to the VBUS pin of the USB interface 101.

In the embodiment of the present application, the control circuit 102 can more accurately control the time when the pull-up circuit 105 outputs the first voltage in at least the following two ways:

In a possible implementation, the control circuit 102 may start the DP comparison for executing the BC1.2 protocol after the time for controlling the charging management circuit 106 to output the charging voltage to the VBUS pin of the USB interface 101 reaches the first time delay.器: After receiving the third detection signal provided by the DP comparator, then control the pull-up circuit 105 to provide the first voltage to the DM pin.

In another possible implementation manner, the control circuit 102 may detect the voltage of the digital positive DP pin of the USB interface 101 after determining that the USB interface 101 is connected to the main device end of the USB OTG line 300; after detecting the DP pin After the voltage of is greater than the third threshold voltage, the pull-up circuit 105 is controlled to provide the first voltage to the DM pin.

In the embodiment of the present application, there are multiple possible implementation manners for the pull-up circuit 105, for example:

In a possible implementation, the pull-up circuit 105 includes a first switch tube and a first resistor; wherein, the control electrode of the first switch tube is coupled to the control circuit 102, and the first electrode of the first switch tube is coupled to the first resistor. The second electrode of the first switch tube is coupled to the DM pin, and the other end of the first resistor is used to receive the basic voltage; the control circuit 102 can determine that the USB interface 101 is connected to the main device end of the USB OTG line 300 , Turn on the first switch tube.

Exemplarily, the pull-up circuit 105 may further include a second resistor, one end of the second resistor is coupled to the control circuit 102, and the other end of the second resistor is coupled to the control electrode of the first switch tube.

Exemplarily, the above-mentioned basic voltage may be the voltage provided by the control circuit 102 or the power management circuit 103 for the pull-up circuit 105.

In another possible implementation manner, the pull-up circuit 105 includes a third resistor; one end of the third resistor is coupled to the control circuit 102, and the other end of the third resistor is coupled to the DM pin; the control circuit 102 can determine the USB After the interface 101 is connected to the main device end of the USB OTG line 300, it outputs the basic voltage to the third resistor.

Obviously, those skilled in the art can make various changes and modifications to the application without departing from the spirit and scope of the application. In this way, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalent technologies, this application is also intended to include these modifications and variations.

Claims

An electronic device, characterized by comprising: a universal serial bus USB interface, a pull-up circuit and a control circuit, the USB interface being a standard downstream port SDP;

Wherein, the pull-up circuit is respectively coupled with the digital negative DM pin of the USB interface and the control circuit;

The control circuit is used for:

After it is determined that the USB interface is connected to the main device end of the USB movable OTG line, the pull-up circuit is controlled to provide a first voltage to the DM pin, and the first voltage is used to indicate that the USB interface is charging Downstream port CDP.
The electronic device according to claim 1, wherein the electronic device further comprises a power management circuit, and the power management circuit is coupled to a trigger pin of the USB interface;

The power management circuit is configured to send a first detection signal to the control circuit after detecting that the voltage of the trigger pin is lower than a first threshold voltage;

The control circuit is further configured to: after receiving the first detection signal, determine that the USB interface is connected to the host device end of the USBOTG line.
The electronic device according to claim 1, wherein the control circuit is further coupled with a trigger pin of the USB interface;

The control circuit is further configured to: after detecting that the voltage of the trigger pin is lower than the first threshold voltage, determine that the USB interface is connected to the main device end of the USB OTG line.
The electronic device according to any one of claims 1 to 3, wherein the electronic device further comprises a charging management circuit, and the charging management circuit is coupled to the VBUS pin of the USB interface;

The control circuit is also used to control the charging management circuit to output a charging voltage to the VBUS pin of the USB interface after determining that the USB interface is connected to the main device end of the USB OTG line.
The electronic device according to claim 4, wherein the control circuit is specifically used for:

After controlling the charging management circuit to output the charging voltage to the VBUS pin of the USB interface for the first time delay, turn on the DP comparator for executing the BC1.2 protocol;

After receiving the third detection signal provided by the DP comparator, control the pull-up circuit to provide the first voltage to the DM pin.
The electronic device according to any one of claims 1 to 4, wherein the control circuit is specifically used for:

After determining that the USB interface is connected to the main device end of the USB OTG line, detecting the voltage of the digital positive DP pin of the USB interface;

After detecting that the voltage of the DP pin is greater than the third threshold voltage, the pull-up circuit is controlled to provide the first voltage to the DM pin.
The electronic device according to claim 5 or 6, wherein the control circuit is further used for:

After the time for controlling the pull-up circuit to provide the first voltage to the DM pin reaches the second time delay, the pull-up circuit is controlled to stop providing the first voltage to the DM pin.
The electronic device according to any one of claims 1 to 7, wherein the pull-up circuit comprises a first switch tube and a first resistor;

The control electrode of the first switch tube is coupled with the control circuit, the first electrode of the first switch tube is coupled with one end of the first resistor, and the second electrode of the first switch tube is coupled with the DM Pin coupling, the other end of the first resistor is used to receive the basic voltage;

The control circuit is specifically used for:

After it is determined that the USB interface is connected to the main device end of the USB OTG line, the first switch tube is turned on.
8. The electronic device according to claim 8, wherein the pull-up circuit further comprises a second resistor, one end of the second resistor is coupled to the control circuit, and the other end of the second resistor is coupled to the control circuit. The control electrode of the first switch tube is coupled.
The electronic device according to claim 8 or 9, wherein the first switch tube is a bipolar transistor or a field effect transistor.
The electronic device according to any one of claims 8 to 10, wherein the base voltage is a voltage provided by the control circuit or power management circuit for the pull-up circuit.
The electronic device according to any one of claims 1 to 7, wherein the pull-up circuit comprises a third resistor;

One end of the third resistor is coupled with the control circuit, and the other end of the third resistor is coupled with the DM pin;

The control circuit is specifically used for:

After it is determined that the USB interface is connected to the main device end of the USB OTG line, the basic voltage is output to the third resistor.
A reverse charging method, characterized in that it is applied to a control circuit, the control circuit is coupled with a pull-up circuit, the pull-up circuit is coupled with the digital negative DM pin of a universal serial bus USB interface, and the USB interface It is the standard downstream port SDP;

The method includes:

After it is determined that the USB interface is connected to the main device end of the USB movable OTG line, the pull-up circuit is controlled to provide a first voltage to the DM pin, and the first voltage is used to indicate that the USB interface is charging Downstream port CDP.
The method according to claim 13, wherein the control circuit is further coupled with a power management circuit, and the power management circuit is coupled with a trigger pin of the USB interface; the power management circuit is used for detecting Sending a first detection signal to the control circuit after the voltage of the trigger pin is lower than the first threshold voltage;

The method further includes: after receiving the first detection signal, determining that the USB interface is connected to the main device end of the USB OTG line.
The method according to claim 13, wherein the control circuit is further coupled with a trigger pin of the USB interface;

The method further includes: after detecting that the voltage of the trigger pin is lower than the first threshold voltage, determining that the USB interface is connected to the main device end of the USB OTG line.
The method according to any one of claims 13 to 15, wherein the control circuit is further coupled with a charging management circuit, and the charging management circuit is coupled with the VBUS pin of the USB interface;

After determining that the USB interface is connected to the main device end of the USB OTG line, the method further includes: controlling the charging management circuit to output a charging voltage to the VBUS pin of the USB interface.
The method according to claim 16, wherein after determining that the USB interface is connected to the main device end of the USB OTG line, the pull-up circuit is controlled to provide the first voltage to the DM pin, and the second A voltage is used to indicate that the USB interface is a charging downstream port CDP, including:

After controlling the charging management circuit to output the charging voltage to the VBUS pin of the USB interface for the first time delay, turn on the DP comparator for executing the BC1.2 protocol;

After receiving the third detection signal provided by the DP comparator, control the pull-up circuit to provide the first voltage to the DM pin.
The method according to any one of claims 13 to 16, wherein after determining that the USB interface is connected to the main device end of the USB OTG line, the pull-up circuit is controlled to provide the DM pin with a A voltage, the first voltage is used to indicate that the USB interface is a charging downstream port CDP, including:

After determining that the USB interface is connected to the main device end of the USB OTG line, detecting the voltage of the digital positive DP pin of the USB interface;

After detecting that the voltage of the DP pin is greater than the third threshold voltage, the pull-up circuit is controlled to provide the first voltage to the DM pin.
The method according to claim 17 or 18, wherein after controlling the pull-up circuit to provide the first voltage to the DM pin, the method further comprises:

After the time for controlling the pull-up circuit to provide the first voltage to the DM pin reaches the second time delay, the pull-up circuit is controlled to stop providing the first voltage to the DM pin.
The method according to any one of claims 13 to 19, wherein the pull-up circuit comprises a first switch tube and a first resistor;

The control electrode of the first switch tube is coupled with the control circuit, the first electrode of the first switch tube is coupled with one end of the first resistor, and the second electrode of the first switch tube is coupled with the DM Pin coupling, the other end of the first resistor is used to receive the basic voltage;

After determining that the USB interface is connected to the main device end of the USB OTG line, controlling the pull-up circuit to provide the first voltage to the DM pin includes:

After it is determined that the USB interface is connected to the main device end of the USB OTG line, the first switch tube is turned on.
The method according to claim 20, wherein the pull-up circuit further comprises a second resistor, one end of the second resistor is coupled to the control circuit, and the other end of the second resistor is coupled to the first resistor. The control electrode of a switch tube is coupled.
The method according to claim 20 or 21, wherein the first switch tube is a bipolar transistor or a field effect transistor.
The method according to any one of claims 20 to 22, wherein the base voltage is a voltage provided by the control circuit or power management circuit for the pull-up circuit.
The method according to any one of claims 13 to 19, wherein the pull-up circuit comprises a third resistor;

One end of the third resistor is coupled with the control circuit, and the other end of the third resistor is coupled with the DM pin;

After determining that the USB interface is connected to the main device end of the USB OTG line, controlling the pull-up circuit to provide the first voltage to the DM pin includes:

After it is determined that the USB interface is connected to the main device end of the USB OTG line, the basic voltage is output to the third resistor.