WO2012167677A1

WO2012167677A1 - Device and method for communication and charging for external device via usb interface

Info

Publication number: WO2012167677A1
Application number: PCT/CN2012/074864
Authority: WO
Inventors: 王晖
Original assignee: 中兴通讯股份有限公司
Priority date: 2011-06-09
Filing date: 2012-04-27
Publication date: 2012-12-13
Also published as: CN102820682B; CN102820682A

Abstract

A device and method for communication and charging for an external device via a universal serial bus (USB) interface, for solving the problem in the prior art that communication cannot be performed via a USB interface while fast charging. A current detection circuit (12) of the device is respectively connected to a management module (13), a current source (11) and a USB interface (15), and outputs a first detection signal according to the current outputted by the current source (11). The management module (13) outputs a second control signal, then delays outputting a first control signal according to the first detection signal from the current detection circuit (12). A diverter switch (14) connected to the management module (13) short-circuits two USB data wires of the USB interface (15) according to the second control signal, and disconnects the two short-circuited USB data wires of the USB interface (15) according to the first control signal. Since the disconnection of the two short-circuited USB data wires after being inserted by a charging device by way of the control of the management module (13) is delayed, the charged device can first choose an adapter mode to perform fast charging by a large current, and then realize communication via the USB data wires.

Description

Device and method for communicating through USB interface and charging external device

The present invention relates to the field of Universal Serial Bus (USB), and more particularly to an apparatus and method for communicating over a USB interface and charging an external device. Background technique

As a standard protocol interface, USB is a standard interface used by a variety of peripherals to support high-volume data transmission and support hot-swap. At present, the field of wireless communication is developing rapidly, and various communication devices, such as personal hand-held phones, business-to-business, and tablet-type products, are increasingly used by users. The USB interface, with its standard and easy implementation, is also the preferred interface for these devices.

At the same time, for most mobile communication devices, battery power is required, so the battery needs to be charged. In some mobile communication devices, the USB port is usually used for charging, and the integrated form of data and power supply is external to the device. The simplicity and practicality of the interface provides a solution. Generally, as a mobile communication device of a charged device, its USB port is connected to an adapter. If it is only used as a charging port, the data line D+/D- line in the USB interface is short-circuited inside the adapter, and is used as communication and charging. For the interface, the data line D+/D- in the USB interface of the device being charged is open. The charging chip of the charged device determines the external state through the connection state of the data line D+/D- in the USB interface, thereby setting the charging current. If the mobile communication device is charged with an adapter, the adapter mode current is supplied for charging, such as a large current of 1A or more; if it is a data line, according to the USB 2.0 protocol, it can only be charged with a maximum of 500mA. For applications where communication is required, the 500 mA charging current is increasingly unable to meet the requirements of current equipment requiring fast charging.

It can be seen that there is a limitation in the prior art that communication can be performed using both the USB interface and the fast charging. The problem of electricity. Summary of the invention

The object of the present invention is to provide a device and a method for communicating and charging an external device through a USB interface, which are in the prior art and cannot communicate with the USB interface and satisfy the problem of fast charging. The USB interface provides a current source of the adapter mode current, and the current output port is directly connected to the current input port of the current detecting circuit;

The current detecting circuit has a current output port connected to the positive terminal USB_VBUS line of the USB interface, and outputs a first detection signal according to a current output of the current source;

a management module, wherein the detection signal input port is connected to the current detection circuit detection signal output port, outputting the second control signal, and then delaying outputting the first control signal according to the first detection signal from the current detection circuit;

The switch, the control signal input port of the switch is connected with the control signal output port of the management module, and the two USB data lines of the USB interface are short-circuited according to the second control signal, and the two short-circuited USB interfaces are according to the first control signal. Striped USB data cable;

The USB interface has two data lines connected to the switch.

Preferably, the management module is a CPU having a USB interface.

Preferably, the two USB data lines of the CPU having the USB interface are connected to the switch, and the switch is disconnected from the two USB data lines of the CPU and the two USB data lines of the USB interface according to the second control signal, according to The first control signal respectively connects the two USB data lines of the CPU to the two USB data lines of the USB interface.

Preferably, the management module is a delay circuit including a D flip-flop.

Preferably, the delay circuit of the D flip-flop includes: a pre-stage D flip-flop, a post-stage D flip-flop, a counter, a logic AND gate, and a clock signal source.

Preferably, the management module immediately outputs the second control signal according to the first detection signal, and then delays outputting the first control signal. Preferably, the current detecting circuit outputs a second detection signal management module according to the current source having no current output, and outputs a second control signal according to the second detection signal.

Preferably, the current detecting circuit comprises:

The resistor is connected to the current input port of the current detecting circuit and the current output port, and is connected to the current source current output port and the USB_VBUS line of the USB interface;

The comparator has two input pins connected to the two ends of the resistor, and the output pin serves as a detection signal output port of the current detecting circuit, and is connected to the detection signal input port of the management module.

Preferably, the current output port of the current detecting circuit and the USB interface between the USB interface and the USB interface have an interface protection circuit.

Embodiments of the present invention also provide a method for communicating through a USB interface and charging an external device, including:

A current interrupt flows according to the detected USB interface and a current source that supplies an adapter mode current to the USB interface, and a timer interrupt is set;

When the timer expires, the first control signal is output, and the two USB data lines of the USB interface that were previously shorted according to the second control signal are disconnected;

Preferably, the second detection signal is output according to the current source having no current output, and the second control signal is output according to the second detection signal.

Preferably, the second control signal is immediately output according to the first detection signal, and then the first control signal is delayed.

Since the shorted two USB data lines are delayed after being inserted by the management module through the management module, the charged device first selects the adapter mode high current for fast charging, and then communicates through the USB data line. DRAWINGS

Figure 1 is a block diagram showing the structure of the apparatus provided by the present invention; 2 is a structural diagram of a device having a USB interface provided by the present invention; FIG. 3 is a structural diagram showing a delay circuit of a D flip-flop of the device provided by the present invention;

Figure 4 is a block diagram showing the structure of a current detecting circuit of the apparatus provided by the present invention;

Figure 5 shows a flow chart of the method provided by the present invention. detailed description

The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings to solve the problem that the prior art cannot communicate with both the USB interface and the fast charging. A first embodiment of the present invention is a device for communicating via a USB interface and charging an external device (as a mobile communication device of the device to be charged). The device will be described in principle with reference to FIG. 1, which includes The current source 11, the current detecting circuit 12, the management module 13, the switch 14 and the USB interface 15, the current source 11 can adopt an existing DC/DC module in the device, and provide an adapter mode current such as 1.5A or 2A for the USB interface. According to the existing USB standard, a power supply of 5V output is preferably used. The current output port of the current source 11 is directly connected to the current input port of the current detecting circuit 12, and the detection signal output port is connected to the detection signal input port of the management module 13. The current output port of the current detecting circuit 12 is connected to the power supply positive USB_VBUS line of the USB interface 15 of the device, and according to the current source 11 having a current output, the detection signal output port of the current detecting circuit 12 outputs a first detection signal, and the detection of the USB interface 15 is performed. Is there a current output on the USB_VBUS line to determine whether an external device is inserted through the USB interface 15, when an external device is inserted, the current detecting circuit detects a current output, and outputs a first detection signal, which may be a high power The flat or low level indicates, or is represented by a level signal of a certain period, which is not limited in this embodiment. The detection signal input port of the management module 13 is connected to the detection signal output port of the current detecting circuit 12, and the management module 13 outputs the second control signal, and then delays outputting the first control signal according to the first detection signal of the current detecting circuit 12, the first control The signal may be expressed as a high level or a low level, and the similar second detection signal and the second control signal are respectively represented by signals different from the first detection signal and the first control signal, and are not described herein again. Switch 14 The control signal input port is connected to the control signal output port of the management module 13, and the two USB data lines D+/D- of the USB interface 15 are short-circuited according to the second control signal, and the shorted USB interface 15 is connected according to the first control signal. The two USB data lines D+/D- are disconnected. The two data lines D+/D- of the USB interface 15 are connected to the changeover switch.

In a specific implementation, the management module 13 can adopt a central processing unit (CPU) having a USB interface, so that the control can be implemented by software, and after outputting the second control signal, the first output is delayed according to the first detection signal. control signal. If a CPU with a USB interface is used as the management module, the preferred scheme is as shown in FIG. 2. The two USB data lines D+/D- of the CPU having the USB interface are connected to the switch 14, and the switch 14 can adopt double-pole double throw. The switch structure disconnects the connection between the two USB data lines D+/D- of the CPU and the two USB data lines D+/D- of the USB interface according to the second control signal (in combination with the two USB data lines of the USB interface) D+/D-short connection), according to the first control signal, the two USB data lines D+/D- of the CPU are respectively connected with the two USB data lines D+/D- of the USB interface (in combination with the foregoing, two of the USB interfaces) Strip USB data cable D+/D-disconnected). Of course, it is not limited to the above circuit structure. It can also be that the two USB data lines D+/D- of the CPU and the two USB data lines D+/D- of the USB interface are directly connected without a switch, through a single-pole single-throw switch. Shorten or disconnect the two USB data lines D+/D-, but you need to add protection circuit to the USB interface of the CPU to prevent damage during short circuit.

The management module 13 can also adopt a delay circuit including a D flip-flop as shown in FIG. 3. The structure includes the following: a logic AND gate 131, an inlet of which is connected to the detection signal output port of the current detecting circuit 12, and inputs a detection signal. The other input port is connected to the Q non-pin of the first D flip-flop 132. The front stage D flip-flop 132 has its D pin connected to the detection signal output port of the current detecting circuit 12, the CLR clear pin and the D pin are shorted, and the clock input pin and the counter 133 count overflow (carry out ) Pin connections. The counter 133 has a direct reset (reset) pin and an output pin of the AND gate 131, and the clock input pin is externally connected to the clock signal source 135. Post-D trigger The clock input pin is connected to the carry out pin of the counter 133, and the D pin is short-circuited with the Q non-pin. The set pin is externally connected to the detection signal output port of the current detecting circuit 12, and the Q pin is output. control signal. It can be realized by the above circuit, assuming that the first detection signal is a first control signal whose high level delay output is low level, and the second control signal which is directly output to a high level according to the second detection signal is low level. If the first detection signal is at a low level and the second detection signal is at a high level, an NAND gate may be added to the line of the detection signal input. The above circuit is only an exemplary description, and the solution of the embodiment of the present invention is not correct. This is limited, and similar delay circuits are implemented in many ways, and are not described here.

In a specific implementation, the management module 13 can immediately output the second control signal according to the input first detection signal, and then delay the output by 1 second to output the first control signal. That is, after the external device is inserted, the device detects that the external device is inserted, first shorts the two USB data lines D+/D- of the disconnected USB interface, and then shorts the USB interface according to the delay control of the management module 13. The two USB data lines D+/D- are disconnected. After the external device is inserted, the external device can detect the D+/D- short circuit of the two USB data lines of the USB interface, and the charging chip of the external device is short-circuited through the connection state of the data line D+/D- in the USB interface, thereby Set the charging current to an adapter mode current such as 1.5A or 2A. The object of the present invention can be achieved by only requiring one detection signal.

In a specific implementation, the current detecting circuit 12 may output a second detection signal according to the current source having no current output. The management module 13 outputs a second control signal according to the second detection signal. That is, after the external device is unplugged, the device detects that the external device is unplugged, shorts the data line D+/D- in the disconnected USB interface, and waits until the external device is inserted, then the data line D+/ in the USB interface at this time. D- is already shorted. According to the delay control of the management module 13, the two USB data lines D+/D- of the shorted USB interface are disconnected. With the circuit of the present configuration, the initial state of the changeover switch 14 is set to a state in which the USB data line is short-circuited, and can be switched and controlled by the management module 13. When the external device is connected to the device, a current is generated on the VBUS and is detected by the current detecting circuit 12. Measured. After the management module 13 knows that there is an external device access, it delays by the timer, and after the delay is completed, the switch 14 is switched to the data state for communication with an external device such as a mobile communication product. During this delay time, the charging management chip of the external device knows that there is power supply through VBUS, and the external device adds a short pulse of 0.6V to the D- line of the data line in the USB bus, and detects the USB bus at the same time. The level state of the D+ line of the data line. If this 0.6V short pulse is also generated on the D+ line, the D+/D- line is considered to be short-circuited, and the connected power source is from the high-current charger, setting the charging current to the corresponding high current state; , it is considered that the data line is connected, and the charging current is set to a state of at most 500 mA. Since the USB cable is switched to the adapter state when the external device performs current source detection, that is, the data line D+/D- in the USB bus is short-circuited, so the external device considers that the connected power source is a high-current charger. Set the charging current to the corresponding high current and no longer change during future use. Thus, when the switch 14 is subsequently switched to the data line state, the change of the charging current is not affected, and normal communication can be performed.

The current detecting circuit 12 can be implemented by using the line structure of FIG. 4, including: a resistor 121 and a comparator 122. Both ends of the current input port and the current output port of the current detecting circuit 12 are respectively connected to the current source 11 current output port and the USB_VBUS line of the USB interface 15, and the two input pins of the comparator 122 and the resistor are respectively The two ends are connected, and the output pin is used as a detection signal output port of the current detecting circuit 12, and is connected to the detection signal input port of the management module 13. When a current flows through the resistor 121, a voltage difference is generated across the resistor 121, and the comparator can output the first detection signal according to the differential pressure. The current detection is implemented in many ways. The solution in this embodiment is only an exemplary description. , is not a limitation of the current detection circuit.

In order to prevent the influence of the instantaneous large current caused by the insertion and removal of the external device on the device, the current output port of the current detecting circuit 12 and the USB positive terminal USB_VBUS line between the USB interface 15 have an interface protection circuit.

The USB interface 15 can be a standard USB interface or other expansion including a USB bus. Exhibition interface.

When the mobile communication device is removed, the current detecting circuit 12 notifies the management module 13 of this state, and the management module 13 switches the analog switch to the initial state, that is, the adapter state, waiting for the next access action of the mobile communication product.

The switch 14 implements switching between the adapter state and the data state of the data line D+/D- in the USB bus of the USB interface 15 under the control of the management module 13, and the current source 11 supplies a large current to the external device connected to the USB interface. , so that the charged device first selects the adapter mode large current for fast charging, and then realizes communication through the USB data line.

The method for communicating through the USB interface and charging the external device according to the present invention will be described in detail below with reference to FIG. 5, including:

Step 201: Set a timer interrupt according to a current flowing between the detected USB interface and a current source that supplies an adapter mode current to the USB interface.

Step 202: When the timer expires, the first control signal is output, and the two USB data lines of the USB interface that were previously shorted according to the second control signal are disconnected.

In the specific implementation, regarding the acquisition of the second control signal, before the step 201 is implemented, the CPU of the USB interface outputs a second detection signal when the current source has no current output, and outputs a second control signal according to the second detection signal.

Or, when the step 202 is implemented, the second control signal is immediately output according to the first detection signal. The first control signal is then delayed.

It should be noted that the above embodiments are only intended to illustrate the technical solutions of the present invention and are not to be construed as limiting the embodiments of the present invention. The technical solutions of the present invention may be modified or equivalently substituted, and the modified technical solutions may not deviate from the spirit and scope of the technical solutions of the present invention.

Claims

Claim

1. A device for communicating via a USB interface and for charging an external device, comprising: a current source for providing an adapter mode current for a universal serial bus USB interface, the current output port of which is directly connected to the current input port of the current detecting circuit;

The current detecting circuit has a current output port connected to the positive terminal USB_VBUS line of the USB interface, and has a current output according to the current source, and the detection signal output port outputs a first detection signal; the management module, the detection signal input port and the current detecting circuit detecting signal Connecting the output port, outputting the second control signal, and then delaying outputting the first control signal according to the first detection signal from the current detecting circuit;

The USB interface has two data lines connected to the switch.

2. The apparatus of claim 1, wherein the management module is a central processor CPU having a USB interface.

3. The device according to claim 2, wherein two USB data lines of the CPU having the USB interface are connected to the switch, and the switch switches two USB data lines of the CPU and two USB interfaces according to the second control signal. The connection of the USB data line is disconnected, and the two USB data lines of the CPU are respectively connected to the two USB data lines of the USB interface according to the first control signal.

4. The apparatus of claim 1, wherein the management module is a delay circuit including a D flip-flop.

5. The apparatus of claim 5, wherein the delay circuit of the D flip-flop comprises: a pre-stage D flip-flop, a post-stage D flip-flop, a counter, a logic AND gate, and a clock signal source.

6. The apparatus according to claim 1, wherein the management module is further configured to perform the first check according to The measurement signal immediately outputs a second control signal, and then delays outputting the first control signal.

The device of claim 1 , wherein the current detecting circuit is further configured to output a second detection signal according to the current source having no current output;

The management module is further configured to output the second control signal according to the second detection signal.

8. The device according to claim 1, wherein the current detecting circuit comprises: a resistor, which is a current input port of the current detecting circuit and a resistor of the current output port, respectively, and a current source current output port and a USB_VBUS line of the USB interface. Connection

The comparator has two input pins respectively connected to the two ends of the resistor, and the output pin is used as a detection signal output port of the current detecting circuit, and is connected to the detection signal input port of the management module.

9. The device according to claim 1, wherein the current output port of the current detecting circuit and the power supply positive terminal USB_VBUS line between the USB interface and the USB interface have an interface protection circuit.

10. A method of communicating via a USB interface and charging an external device, comprising: setting a timer interrupt according to a current flowing between the detected universal serial bus USB interface and a current source providing an adapter mode current for the USB interface ;

When the timer expires, the first control signal is output, and the previous control signal is shorted according to the second control signal.

The two USB data lines of the USB interface are disconnected.

11. The method according to claim 10, wherein the second detection signal is output according to the current source having no current output, and the second control signal is output according to the second detection signal.

The method according to claim 10, wherein the second control signal is immediately output according to the first detection signal, and then the first control signal is delayed.