CN107643998A - OTG and the difunctional system that charges are realized based on intelligent object - Google Patents

Abstract

The invention discloses a system for realizing dual functions of OTG and charging based on an intelligent module, which includes an intelligent module, a switching circuit, an adapter input terminal and a USB port, the intelligent module includes a USB function unit, a charging management unit, and GPIO pins, and the intelligent module is based on The USB specification obtains the connected device type, that is, when it detects that the USB power supply pin changes from low level to high level and the USB ID pin changes from high level to low level, it indicates that the adapter and the OTG slave device coexist. At this time, the smart The module sets the GPIO pin to a high level to control the switching circuit to use the adapter as the power supply of the smart module and to charge it, and to supply power to the OTG slave device from the power supply of the smart module, thereby realizing the dual functions of OTG and charging. The invention separates the adapter from the power supply hardware of the OTG slave equipment through the switching circuit, and uses the software process to control the switching circuit to realize the complete separation to realize the dual functions of OTG and charging.

Description

A system that realizes dual functions of OTG and charging based on an intelligent module

technical field

The invention relates to the field of intelligent equipment, in particular to a system for realizing dual functions of OTG and charging based on an intelligent module.

Background technique

The existing smart terminal is using OTG (On the Go, mainly used for connection between various devices or mobile devices for data exchange) slave device, the smart terminal is the host (master device), and when charging, the smart terminal As a device (slave device), the smart terminal does not support charging when using the OTG slave device, or does not support the OTG slave device when charging, but more and more customers need to be able to charge when the smart terminal device is used as a host. In order to ensure that the device will not be shut down due to battery depletion during continuous use.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the defect that the intelligent terminal does not support charging when using the OTG slave device in the prior art, or does not support the defect of the OTG slave device when charging, and provides a dual function of OTG and charging based on an intelligent module. system.

The present invention solves the above technical problems through the following technical solutions:

A system that realizes OTG and charging dual functions based on an intelligent module is characterized in that it includes an intelligent module, a switching circuit, an adapter input terminal and a USB port, and the intelligent module includes a USB functional unit, a charging management unit, and a GPIO pin, and the The USB functional unit includes a USB power supply pin, a USB data positive terminal pin, a USB data negative terminal pin, and a USB ID pin, the charging management unit includes a power supply pin, and the switching circuit includes a first port, a second port, a third port and a control port, the USB port is used to connect the OTG slave device, the adapter input is used to connect the adapter, and the power supply pin is connected to the power supply of the smart module;

The USB data positive terminal pin, the USB data negative terminal pin, and the USB ID pin are connected to the USB port correspondingly, and the adapter input terminal is connected to the first port and the USB power supply tube respectively. Pin connection, the GPIO pin is connected to the control port, the power supply end of the USB port is connected to the second port, and the power supply pin is connected to the third port;

When the smart module detects that the USB power supply pin changes from low level to high level and when the smart module detects that the USB ID pin changes from high level to low level, the smart module will The GPIO pin is set to a high level to control the switching circuit to disconnect the second port from the first port and to connect the second port to the third port. The module obtains power from the adapter input terminal through the USB power supply pin, and the charging management unit charges the power supply of the smart module through the power supply pin, and the power supply of the smart module passes through the switching The circuit supplies power to the OTG device, and the intelligent module completes data exchange with the OTG slave device through the USB data positive pin and the USB data negative pin.

In this solution, the USB functional unit is used for the intelligent module to realize the USB function. For example, when the device connected to the USB port is an OTG slave device, according to the USB specification, the OTG slave device will transfer the USB The ID pin is pulled low, so that the intelligent module becomes a host, and the OTG function can be realized by the built-in software, and when the device connected to the USB port is the main device such as a PC (personal computer), according to the USB specification, The master device short-circuits the USB data positive terminal pin and the USB data negative terminal pin together so that there is no level difference between the two pins. Software can realize USB charging and/or data communication. For example, when the USB power supply pin is connected to an external power source such as an adapter, the pin level changes from low level to high level. According to the USB specification, the The smart module can know that the USB power supply pin is connected to an external power supply, and then the smart module obtains power from the external power supply, and charges the power supply of the smart module through the charging management unit. Therefore, when the smart module detects that the USB power supply pin changes from low level to high level and the smart module detects that the USB ID pin changes from high level to low level, the The smart module detects that both the external power supply and the OTG slave device are connected, and at this moment the smart module sets the GPIO pin to a high level, which on the one hand makes the switching circuit use the external power supply for The intelligent module supplies power and manages charging the power supply of the intelligent module such as a battery through the charging management unit, and on the other hand makes the switching circuit supply power to the OTG slave device from the power supply of the intelligent module. At this time, the intelligent module completes data exchange with the OTG slave device through the USB data positive pin and the USB data negative pin, so that the intelligent module realizes the coexistence of the OTG function and the charging function.

Preferably, when the smart module detects that the USB power supply pin and the USB data negative pin are both in a low level state and that the USB data positive pin and the USB ID pin are both When the level is high, the intelligent module sets the GPIO pin to a low level by default, and the switching circuit includes a first resistor, a second resistor, a first triode, a second triode and a PMOS tube, so The drain of the PMOS transistor is used as the first port, the source of the PMOS transistor is respectively connected to one end of the first resistor and one end of the second resistor as the second port, and the PMOS transistor The grid of the first resistor is respectively connected to the other end of the first resistor and the collector of the first triode, the emitter of the first triode is grounded, and the base of the first triode is respectively connected to the first triode. The other end of the second resistor is connected to the collector of the second triode, the emitter of the second triode is grounded, and the base of the second triode serves as the control port.

In this solution, the switching circuit utilizes the switching characteristics of MOS transistors (insulated gate field effect transistors) and triodes, and sets the GPIO pins as low power according to the adapter input terminal and the USB port being suspended. level, so as to ensure that the system based on the intelligent module to realize the dual functions of OTG and charging still has a complete and independent OTG function and charging function on the basis of the coexistence of OTG function and charging function, that is, when the adapter input terminal is connected to the adapter alone , the system based on the intelligent module to realize the dual functions of OTG and charging can be charged independently, and the OTG communication can be carried out independently when the USB port is connected to the OTG slave device alone, or the smart The module communicates as a device. Of course, if the OTG slave device and the adapter are connected at the same time, the system that realizes the dual functions of OTG and charging based on the intelligent module has both the OTG function and the charging function.

Preferably, the charging management unit further includes a power supply voltage detection pin, the power supply voltage detection pin is connected to the power supply of the smart module, when the charging management unit detects that the power supply of the smart module is When fully charged, the charging management unit stops charging the power supply of the smart module through the power supply pin.

In this solution, whether to continue charging is determined by monitoring the power state of the power supply of the intelligent module, thereby further improving reliability and safety.

Preferably, the switching circuit further includes a third resistor, one end of the third resistor is connected to the base of the second triode, and the other end is grounded.

Preferably, the switching circuit further includes a voltage stabilizing circuit, and the voltage stabilizing circuit further includes an enable terminal connected to the control port, and the input terminal of the voltage stabilizing circuit is the third port, the output terminal of the voltage stabilizing circuit is the second port, and the enabling terminal is active at a high level for controlling the voltage stabilizing circuit to stabilize the power supply of the intelligent module through the second port. Two port output.

In this solution, the voltage stabilizing circuit is used to match the power supply of the smart module with the power demand of the OTG slave device to further improve the flexibility of use of the system that realizes dual functions of OTG and charging based on the smart module . Wherein, the voltage stabilizing circuit generally adopts a voltage stabilizing chip as a core device. In view of existing applications, the operating voltage range of the smart module is generally 3.5V-4.2V, and the power supply voltage of the OTG slave device is generally 5V, that is, the The voltage value of the power supply of the intelligent module is lower than the power demand of the OTG slave device, so the voltage stabilizing circuit adopts a step-up voltage stabilizing chip.

Preferably, the voltage stabilizing circuit further includes a diode, the output terminal of the voltage stabilizing circuit is connected to the anode of the diode, and the cathode of the diode serves as the second port. In this solution, the unidirectional conduction characteristic of the diode is used to protect the voltage stabilizing circuit, thereby improving circuit reliability and safety.

The positive progress effect of the present invention is: the present invention carries out the hardware separation of the input of external adapter power supply and the power supply of OTG from equipment by increasing switching circuit, and controls switching circuit by GPIO (General Purpose Input/Output, general purpose input/output) interface in conjunction with software flow , so that the input of the external adapter power supply and the power supply of the OTG slave device are completely separated, so that the smart device supports both the OTG slave device and the charging function.

Description of drawings

Fig. 1 is a schematic diagram of a system for realizing dual functions of OTG and charging based on an intelligent module according to a preferred embodiment of the present invention.

Fig. 2 is a schematic flow chart of the built-in software of the system based on the intelligent module to realize the dual functions of OTG and charging according to the preferred embodiment of the present invention.

detailed description

The present invention is further illustrated below by means of examples, but the present invention is not limited to the scope of the examples.

As shown in Figure 1-2, the system for realizing dual functions of OTG and charging based on the intelligent module involved in this embodiment includes an intelligent module 1, a switching circuit 2, an adapter input terminal 3 and a USB port 4, and the intelligent module 1 includes a USB Functional unit 11, charging management unit 12, and GPIO pins. The USB functional unit 11 includes a USB power supply pin USB_VBUS, a USB data positive pin USB_DP, a USB data negative pin USB_DN, and a USB ID pin USB_ID. The charging management unit 12 includes a power supply pin VBAT, the switching circuit 2 includes a first port 21, a second port 22, a third port 23 and a control port 24, and the USB port 4 is used to connect an OTG slave device, and the adapter The input terminal 3 is used to connect the adapter, and the power supply pin VBAT is connected to the power supply 5 of the intelligent module;

The USB data positive pin USB_DP, the USB data negative pin USB_DN, and the USB ID pin USB_ID are connected to the USB port 4 correspondingly, and the adapter input 3 is connected to the first port 21 respectively. , the USB power supply pin USB_VBUS is connected, the GPIO pin is connected to the control port 24, the power supply end of the USB port 4 is connected to the second port 22, and the power supply pin VBAT is connected to the second port 22. Three-port 23 connections;

When the smart module 1 detects that the USB power supply pin USB_VBUS changes from a low level to a high level according to the built-in software process (as shown in FIG. 2 ) and the smart module 1 detects that the USB ID pin USB_ID When changing from a high level to a low level, the intelligent module 1 sets the GPIO pin to a high level for controlling the switching circuit 2 to disconnect the second port 22 from the first port 21 And connect the second port 22 with the third port 23, the smart module 1 obtains power from the adapter input 3 through the USB power supply pin USB_VBUS, and the charging management unit 12 obtains power through the The power supply pin VBAT charges the power supply 5 of the smart module 1 and the power supply 5 of the smart module 1 charges the OTG slave device (the OTG slave device is not marked in Fig. 1 ) through the switching circuit 2 ), the smart module 1 completes data exchange with the OTG slave device through the USB data positive pin USB_DP and the USB data negative pin USB_DN. In the specific implementation of this embodiment, the power supply 5 of the intelligent module 1 is generally preferably a battery, such as a lithium battery, and can be a single-cell lithium battery or a double-cell lithium battery connected in parallel, and the voltage of a single-cell lithium battery is generally 4.2V. Described intelligent module 1 comprises intelligent chip, such as direct preferred high-pass msm8909 platform as the core of described intelligent module, this platform includes functional units such as USB, charging management, so when the equipment that is inserted into described USB port 4 is OTG When a slave device, according to the USB specification, the OTG slave device will pull down the USB ID pin USB_ID at this time, so that the intelligent module 1 becomes a host, and the OTG function can be realized through the built-in software, and when connected to the When the device of the USB port 4 is a master device (the master device is not identified in Fig. 1 ) such as a PC (personal computer), according to the USB specification, the master device connects the USB data positive terminal pin USB_DP to the USB data negative terminal The pins USB_DN are shorted together so that there is no level difference between the two pins. At this time, the smart module 1 is used as a device, and USB charging and/or data communication can be realized through the built-in software. When the USB power supply pin USB_VBUS is connected to an external power source such as an adapter, the pin level changes from low level to high level. According to the USB specification, the smart module can know that the USB power supply pin USB_VBUS is connected An external power source, at this time, the smart module 1 obtains power from the external power source, and charges the power supply 5 of the smart module 1 through the charging management unit 12 . Therefore, when the smart module 1 detects that the USB power supply pin USB_VBUS changes from a low level to a high level and the smart module 1 detects that the USB ID pin USB_ID changes from a high level to a low level , that is, the smart module 1 detects that both the external power supply and the OTG slave device are connected, and then the smart module 1 sets the GPIO pin to a high level, which on the one hand makes the switching circuit 2 use the external power supply to supply power to the smart module 1 and charge and manage the power supply 5 of the smart module 1 through the charging management unit 12, on the other hand, make the switching circuit 2 switch the smart module The power supply 5 of 1 supplies power to the OTG slave device. At this time, the smart module 1 completes data exchange with the OTG slave device through the USB data positive pin USB_DP and the USB data negative pin USB_DN, so that the smart module is Realized the coexistence of OTG function and charging function.

Further, in this embodiment, after the intelligent module 1 detects that the USB power supply pin USB_VBUS and the USB data negative terminal pin USB_DM are both in a low level state and that the USB data positive terminal pin USB_DP, all When the USB ID pins USB_ID are all at high level, the intelligent module 1 sets the GPIO pin to low level by default, and the switching circuit 2 includes a first resistor R1, a second resistor R2, a first three-pole A transistor Q2, a second triode Q3, and a PMOS transistor Q1, the drain of the PMOS transistor Q1 is used as the first port 21, and the source of the PMOS transistor Q1 is respectively connected to one end of the first resistor R1, One end of the second resistor R2 is connected to serve as the second port 22, and the gate of the PMOS transistor Q1 is respectively connected to the other end of the first resistor R1 and the collector of the first triode Q2. The emitter of the first triode Q2 is grounded, the base of the first triode Q2 is respectively connected to the other end of the second resistor R2 and the collector of the second triode Q3, and the second three The emitter of the transistor Q3 is grounded, and the base of the second transistor Q3 serves as the control port 24 . During specific implementation, the GPIO pin is set to a low level according to the adapter input terminal and the USB port being suspended according to the built-in software process, thereby ensuring that the system based on the intelligent module realizes OTG and charging dual functions On the basis of the coexistence of the OTG function and the charging function, it still has a complete and independent OTG function and charging function, that is, when the adapter input terminal 3 is connected to the adapter alone, the system that realizes the dual functions of OTG and charging based on the intelligent module can be Independent charging, when the USB port 4 is connected to the OTG slave device alone, the OTG communication can be carried out independently, or when the USB port 4 is connected to the master device alone, the intelligent module 1 is used as a device to realize communication. Of course, if the OTG slave device and the adapter are connected at the same time, the system that realizes the dual functions of OTG and charging based on the intelligent module has both the OTG function and the charging function. In a specific implementation, the switching circuit 2 further includes a third resistor R3, one end of the third resistor R3 is connected to the base of the second transistor Q3, and the other end is grounded.

Further, in this embodiment, the charging management unit 12 also includes a power supply voltage detection pin BAT_SNS, the power supply voltage detection pin BAT_SNS is connected to the power supply 5 of the smart module 1, when the charging management unit 12 When detecting that the power supply 5 of the smart module 1 is fully charged, the charging management unit 12 stops charging the power supply 5 of the smart module 1 through the power supply pin BAT_SNS.

Further, in this embodiment, the switching circuit 1 also includes a voltage stabilizing circuit 25, and the voltage stabilizing circuit also includes an enable terminal EN, and the voltage stabilizing circuit 25 generally preferably uses a voltage stabilizing chip 251 as the core of the voltage stabilizing circuit device, the voltage stabilizing circuit 25 also includes a diode D1, the output terminal of the voltage stabilizing circuit 25 is connected to the anode of the diode D1, the cathode of the diode D1 is used as the second port 22, and the enabling terminal EN is connected to the control port 24, the input terminal of the voltage stabilizing circuit 25 is the third port 23, the output terminal of the voltage stabilizing circuit 25 is the second port 22, and the enabling terminal EN is The active high level is used to control the voltage stabilizing circuit 25 to stabilize the power supply 5 of the smart module 1 and output it through the second port 22 . In specific implementation, the operating voltage range of the intelligent module is generally 3.5-4.2V, and the power supply of the OTG from the equipment is 5V, that is, the voltage value of the power supply of the intelligent module is lower than the power demand of the OTG from the equipment. A step-up regulator circuit is used.

As shown in Figure 2, the built-in software process of the system based on the intelligent module to realize the dual functions of OTG and charging involved in this embodiment includes: first, the intelligent module 1 detects whether the USB port 4 is suspended according to the USB specification, such as the intelligent When module 1 detects that the USB power supply pin USB_VBUS and the USB data negative terminal pin USB_DM are both in a low level state and that the USB data positive terminal pin USB_DP and the USB ID pin USB_ID are both in a high level state It indicates that the USB port 4 is in a floating state; then, if it is first detected that the USB port 4 is connected to a device, according to the USB specification, the USB ID pin USB_ID, the USB data positive pin USB_DP, The USB data negative terminal pin USB_DM identifies whether it is an OTG slave device or a master device. If the level of the USB ID pin USB_ID changes from high to low, it is an OTG slave device, otherwise it is a master device so that the smart Module 1 is used as a device, and further judges whether there is an adapter plugged in, that is, judges whether the level of the USB power supply pin USB_VBUS changes from low to high. At this time, if the adapter and the OTG slave device coexist, the OTG and charging functions will be executed. If it is only an OTG slave device, only the OTG function is performed; if it is first detected that the adapter input terminal 3 is connected to an adapter, it is detected whether the level of the USB power supply pin USB_VBUS changes from low to high to indicate that the adapter input If terminal 3 is connected to an adapter, it is further judged whether the USB port 4 is connected to a device, that is, according to the USB specification, through the USB ID pin USB_ID, the USB data positive pin USB_DP, and the USB data negative pin pin USB_DM to identify whether it is an OTG slave device or a master device. If it is an OTG slave device, if the adapter and the OTG slave device coexist at this time, the OTG and charging functions will be performed. If it is only an adapter, only the charging function will be performed; If both the USB port 4 and the adapter input 3 are suspended, the process is always in a waiting state.

Although the specific implementation of the present invention has been described above, those skilled in the art should understand that this is only an example, and the protection scope of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principle and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims (6)

1. A system that realizes OTG and charging dual functions based on an intelligent module, is characterized in that, comprises an intelligent module, a switching circuit, an adapter input terminal and a USB port, and the intelligent module comprises a USB functional unit, a charging management unit, and a GPIO pin , the USB functional unit includes a USB power supply pin, a USB data positive terminal pin, a USB data negative terminal pin, and a USB ID pin, the charging management unit includes a power supply pin, and the switching circuit includes a first port, The second port, the third port and the control port, the USB port is used to connect the OTG slave device, the adapter input is used to connect the adapter, and the power supply pin is connected to the power supply of the smart module; The USB data positive terminal pin, the USB data negative terminal pin, and the USB ID pin are connected to the USB port correspondingly, and the adapter input terminal is connected to the first port and the USB power supply tube respectively. Pin connection, the GPIO pin is connected to the control port, the power supply end of the USB port is connected to the second port, and the power supply pin is connected to the third port; When the smart module detects that the USB power supply pin changes from low level to high level and when the smart module detects that the USB ID pin changes from high level to low level, the smart module will The GPIO pin is set to a high level to control the switching circuit to disconnect the second port from the first port and to connect the second port to the third port. The module obtains power from the adapter input terminal through the USB power supply pin, and the charging management unit charges the power supply of the smart module through the power supply pin, and the power supply of the smart module passes through the switching The circuit supplies power to the OTG slave device, and the intelligent module completes data exchange with the OTG slave device through the USB data positive pin and the USB data negative pin. 2. The system for realizing OTG and charging dual functions based on an intelligent module as claimed in claim 1, wherein the intelligent module detects that the USB power supply pin and the USB data negative terminal pin are both low level state and the USB data positive terminal pin and the USB ID pin are both high level, the intelligent module sets the GPIO pin to low level by default, and the switching circuit includes a first resistor , a second resistor, a first triode, a second triode and a PMOS tube, the drain of the PMOS tube is used as the first port, and the source of the PMOS tube is connected to the first resistor respectively One end and one end of the second resistor are connected as the second port, the gate of the PMOS transistor is respectively connected to the other end of the first resistor and the collector of the first triode, and the first The emitter of the triode is grounded, the base of the first triode is respectively connected to the other end of the second resistor and the collector of the second triode, and the emitter of the second triode is grounded, The base of the second triode serves as the control port. 3. The system for realizing OTG and charging dual functions based on an intelligent module as claimed in claim 1, wherein the charging management unit also includes a power supply voltage detection pin, and the power supply voltage detection pin is connected to the intelligent module When the charging management unit detects that the power supply of the smart module is fully charged, the charging management unit stops charging the power supply of the smart module through the power supply pin. 4. The system for realizing OTG and charging dual functions based on an intelligent module as claimed in claim 2, wherein the switching circuit also includes a third resistor, and one end of the third resistor is connected to the second triode. The base connection and the other end to ground. 5. The system for realizing OTG and charging dual functions based on an intelligent module as claimed in claim 1, wherein the switching circuit also includes a voltage stabilizing circuit, and the voltage stabilizing circuit also includes an enabling terminal, and the enabling The terminal is connected to the control port, the input terminal of the voltage stabilizing circuit is the third port, the output terminal of the voltage stabilizing circuit is the second port, and the enabling terminal is active at high level for The voltage stabilizing circuit is controlled to stabilize the power supply of the intelligent module and output it through the second port. 6. The system for realizing OTG and charging dual functions based on an intelligent module as claimed in claim 5, wherein the voltage stabilizing circuit further comprises a diode, and the output terminal of the voltage stabilizing circuit is connected to the anode of the diode, The cathode of the diode serves as the second port.