TW201107991A - Electronic device capable of switching between a USB master and a USB slave mode automatically - Google Patents

Abstract

An electronic device, includes a USB interface, a processing unit, a master-slave select trigger circuit, a control unit, a selection circuit and a switch circuit. The master-slave select trigger circuit, including an input port, a first output port and a second output port. The master-slave select trigger circuit is used to detect the type of external electronic devices connected to the USB interface, if the external electronic device is a main device, the first and second output port output a slave trigger signal, the control unit controls the switch circuit to turn off and the selection circuit selects the processing unit into slave mode when them receives the slave trigger signal; if the external electronic device is the slave device, the first and second output port output a main trigger signal, the control unit to control the switch circuit turn on and the selection circuit select the processing unit into master mode when them receives the main trigger signal.

Description

201107991 VI. Description of the Invention: [Technical Field] The present invention relates to a USB electronic device, and more particularly to an electronic device capable of automatically switching a mode of a USB master-slave device. [Prior Art] _2] Since the USB standard was jointly proposed by inte Bu Li, Micr〇s〇ft and other companies in 1994, after years of development, the USB interface has been widely used in electronic devices, becoming the standard for electronic devices. One of the interfaces. [0003] It is well known that at present, when many electronic devices are connected to different external electronic devices to exchange data, it is necessary to select working in the ribs (main device mode) or DEVICE according to the type of external electronic devices that are connected. (From the device mode) state, taking the electronic photo frame as an example, when the electronic photo frame is connected to the computer through the USB interface, the electronic photo frame is controlled by the computer as the slave device of the electric device, and is also used as the main device control (10) disk when connected with the U disk. Thus, when the electronic device is connected to the external electronic device, for example, when the electronic phase stick is connected to the computer or the USB flash drive, the electronic device needs to automatically select the master device mode according to the connected external power. Device mode. In the country (10), the existing USB main mode switching circuit structure is more secretive. The number of electronic components H is higher than that of the fresh one, which not only increases the manufacturing cost but also increases the consumption of power. SUMMARY OF THE INVENTION [0005] In view of this, it is necessary to provide an electronic device with a simple USB master-slave mode switching circuit, which can be automatically switched according to different external device types. , the master-slave mode switch form number 腾 1 S 4 _ 18 stomach ' stomach 0982049184-0 201107991 [0006] [0007] Ο [0008] Ο [0009] [0010] The circuit is simple and effective, reducing the use of electronic components , thereby reducing manufacturing costs. In order to solve the technical problem of the present invention, the present invention generally provides an electronic device capable of automatically switching a USB master-slave mode for switching an electronic device master-slave mode, the electronic device including a USB interface, a processing unit, and A power supply, the USB interface includes a USB power pin and a USB data pin. The automatically switchable USB master-slave mode further includes a master-slave selection trigger circuit, a switch circuit, a control unit, and a selection circuit. The master-slave selection trigger circuit includes an input terminal, a first output terminal and a second output terminal, the input terminal being connected to the USB power supply pin, the first output terminal being connected to the control unit and the second output terminal Connect to the selection circuit. The master-slave selection trigger circuit is configured to detect an external electronic device type connected to the electronic device through the USB interface. When the external electronic device is detected as the main device, the slave trigger signal is sent through the first and second output terminals. When detecting that the external electronic device is a slave device, sending a main trigger signal through the first and second output terminals, the switch circuit is connected between the power supply of the electronic device and the USB power pin, and the control unit is further The switch circuit is connected to receive a trigger signal outputted by the first output end. When the trigger signal is a slave trigger signal, the switch control unit controls the switch unit to be turned off, and the power of the electronic device and the USB power pin are cut off. Connection, when the trigger signal is the main trigger signal, then the switch control unit controls the switch unit to be turned on, the electronic 098128644 Form No. A0101 Page 5 / 18 pages 0992049184-0 201107991 Device power supply to the USB power pin powered by. [0013] 00128644 The selection circuit is configured to select a master-slave mode of the processing unit according to the trigger signal received from the second output terminal, and when the trigger signal is a slave trigger signal, the slave device of the processing unit a pin is connected to the USB data pin, the processing unit controls the electronic device to operate in a slave mode, and when the trigger signal is a main trigger signal, the master device pin controlled by the processing unit is connected to the USB data pin, The processing unit controls the electronic device to operate in a master mode. Compared with the prior art, the master-slave selection trigger circuit of the invention has a simple structure, reduces the use of the electronic device, reduces the manufacturing cost of the USB master-slave mode switching circuit, and reduces the USB master-slave mode switching: the power consumption of the circuit. [Embodiment] As shown in Fig. 1, a functional module diagram of an electronic device capable of automatically switching a USB master-slave mode is shown. The electronic device i includes a USB master-slave mode switching circuit 10 and a USB interface 20. In this embodiment, the uSB interface 20 can be a Mini USB interface or a Type A or Type B USB interface. When the electronic device 1 is connected to the external electronic device 2 through the USB interface 20, the USB master-slave mode switching circuit 1 determines the type of the external electronic device 2, and when the external device 2 is a main device such as a computer, the USB master-slave The mode switching circuit 10 switches the electronic device! Working in the slave mode, when the USB master-slave mode switching circuit 1 determines that the external electronic device 2 is a slave device such as a USB flash drive, the USB master-slave mode switching circuit 1 switches the electronic device 1 to operate in the master device mode. . The USB master-slave mode switching circuit 1 includes a master-slave selection trigger circuit 1〇1, a control unit 102, a selection circuit 103, and a switch circuit 1〇4 form number A0101 page 6/18 pages 0982049184-0 [ 0014] 201107991 [0015] Ο [0016]

G

[0017]. The USB interface 20 includes a power pin 201 and a data pin 202. The master-slave selection trigger circuit 1〇1 includes an input terminal 11〇, a first output terminal 1012, and a second output terminal 1〇13. The input terminal 1〇11 is connected to the power pin 201 of the USB interface 20. . The first output terminal 〇12 is connected to the control unit 102. The second output terminal 〇13 is connected to the selection circuit 103. The electronic device 1 further includes a processing unit 30 and a power supply unit 〇. The processing unit 40 includes a slave control pin 3〇1 and a master device control pin 302.

The master-slave selection trigger circuit 101 is configured to detect the type of the external electronic device 2 connected to the electronic device via the USB, . . . , interface 20. When the master-slave selection trigger circuit 101 detects that the power pin 2〇1 connected to the wheelfill 1011 is at a high level, the master-slave selection trigger circuit 101 determines that the external electronic device 2 is the master device, and passes the The second output sends a slave trigger signal. When the master-slave selection trigger circuit 101 detects that the power pin 201 connected to the input terminal 1 is low level, the master-slave selection trigger circuit 1〇1 determines that the external electronic device 2 is a slave device. The device sends a main trigger signal through the first and second outputs. The control unit 102 is also connected to the switch circuit 1〇4, and the switch circuit 104 is simultaneously connected between the power source 40 and the USB power pin 2〇1. When the control unit 102 receives the slave trigger signal sent by the first output terminal, the β-axis control early element 1 〇 2 controls the switch circuit 1 〇 4 to be turned off, and the connection of the power source 4 〇 to the USB power pin 201 is cut off. . When the control unit 102 receives the main trigger signal sent by the first output terminal, the control unit 102 controls the switch circuit 104 to be turned on, and the power source 40 supplies power to the USB power pin 2〇1 098128644 Form No. A0101 Page 7/ A total of 18 pages 0992049184-0 201107991 [0018] The selection circuit 103 is connected to the second output terminal 13 13 for selecting the slave device control of the processing unit 3 according to receiving a trigger signal from the second output terminal. Pin 3.1 or the master control pin 302 is coupled to the data pin 202 of the USB interface 20. When the selection circuit 1〇3 receives the slave trigger signal from the second output terminal 1013, the selection circuit 1〇3 controls the data of the slave device control pin 3〇1 of the processing unit 30 and the USB interface 20. Pin 202 is connected. When the selection circuit 1〇3 receives the main trigger signal sent by the second output terminal 1013, the selection circuit controls the master device of the processing unit 30. 302 is connected to the data pin 202 of the face (four). Therefore, when the external electronic device connected to the USB interface 20 of the electronic device 1 is the main device, the electronic device 1 does not supply power to the power pin 201 of the USB interface 20, and the processing unit 30 From the connection of the device control pin 301 to the data pin 202 of the USB interface 20, the electronic device 1 operates... in the slave device mode. When the external electronic device connected to the interface 20 of the electronic device 1 is a slave device, the electronic device 1 supplies power to the power pin 201 of the USB interface 30, and the master device control pin 302 of the processing unit 40 and the USB device The data pin 202 of the interface 20 is connected, and the electronic device 1 operates in the master mode. [0020] As shown in FIG. 2, it is a specific circuit diagram of an electronic device that can automatically switch the USB master-slave mode. In the present embodiment, the master-slave selection trigger circuit 101 includes a first resistor R1, a second resistor R2, and a third resistor R3'. The connection node a of the first resistor R1 and the second resistor R2 constitutes the master-slave selection. Input terminal 1011 of trigger circuit 101 'The first resistor R1 is away from the 098128644 Form No. A0101 Page 8 / 18 pages 0992049184-0 201107991 [0021] Ο [0022] [0024] [0025] [0025] The R2 terminal Β constitutes the first output terminal 1012 of the master-slave selection trigger circuit 101, and the connection point C of the second resistor R2 and the second resistor Μ constitutes the second output terminal 1013 of the master-slave selection trigger circuit 10 The unit 102 is a high-voltage turn-on switch 'including a control terminal, a first conductive terminal and a second conductive terminal. In the present embodiment, the control switch 102 is described by taking a triode Q1 as an example. The control terminal 'the first conduction end and the second conduction end respectively correspond to the base, the emitter and the collector of the triode Qi. In other embodiments, the control unit 102 can be an NMOS transistor. The base of the NPN transistor is connected to the first output terminal 1012, the emitter is grounded, and the collector is connected to a control terminal of the switch circuit 104. In the embodiment, the switch circuit 104 is a high-level switch circuit. 'Includes the control terminal, a first conduction terminal, and a second conduction terminal. The control terminal is connected to the second conductive terminal of the control unit 102, and the first conductive terminal is connected to the power supply 60, and the second conductive terminal is connected to the USB power supply pin 201. In the present embodiment, the switch circuit 1〇4 is an NMOS transistor. In other embodiments, the switch circuit 104 can be an NPN transistor. In the present embodiment, the slave device control pin 301 of the processing unit 30 includes Device D+, Device D - two pins. The master device control pin 302 includes two pins, Host D+ and Host D. The data pin 202 of the USB interface 20 includes -j)+ and a ρ-pin. The selection circuit 103 is specifically a double-pole double-throw switch, and includes a control terminal connected to the second input terminal 1013. The two common terminals are respectively connected to the data pins D+ and ]) of the USB interface 20, and the four contact terminals are respectively connected. Device D+, Device D — pin in slave pin 301 and master D+, Host D in master device pin 302 of processing unit 098128644 Form number A0101 page 9/18 page 0982049184-0 201107991 30 Pin Connection [0026] When the electronic device 1 is connected to the external electronic device 2 as a master device through the USB interface 20. The USB power pin 2〇1 of the USB interface 20 obtains a high level from the external electronic device 2, so that the input terminal 1011 connected to the power pin 2〇1 is also at a high level, the first output terminal 1012. The resistor R1 is connected to the input terminal 1011 to be at a high level. After receiving the high level signal, the control terminal of the NPN transistor Q1 turns on the NPN transistor Q1. The control terminal of the switching circuit ί 04 is at a low level through the turned-on N P N transistor Q1, so that the switching circuit 1〇4 is cut off, and the current path of the power supply 4 to the power supply pin 201 is cut off. [0027] When the input terminal 1011 is at a high level, the second wheel terminal 1〇13 is also at a high level by the voltage dividing action of the resistors R2 and R3, and the selection circuit 103 selects the processing unit 3〇. The Device D+ and Device D- pins are respectively connected to the d+ and D- pins of the USB interface. [0028] When the USB interface 20 is externally connected to the host device, the electronic device does not supply power to the power pin 201 of the USB interface 20 and is selected to be powered by the external host device. Meanwhile, the Device D+, Device D-pin of the processing unit 30 is selected. Connected to the D+, D- pins of the USB interface 20, respectively, the electronic device i is in the slave mode. When the 5H electronic device 1 is connected through the USB interface 20 to an external electronic device as a slave device. The USB power pin 2 of the USB interface 20 is at a low level, so that the input terminal connected to the USB power pin 201 is also 098128644. Form number A0101 Page 10/18 pages 0982049184-0 [0029 ] 201107991 is at a low level. The first output terminal 1012 is connected to the input terminal 〇11 through the resistor R1 and is at a low level. After the control terminal of the ΝΡΝ transistor Q1 receives the low level, the NPN tertiary tube Q1 is turned off. Therefore, the control terminal of the switch circuit 104 is at a high level, the switch circuit 1〇4 is turned on, and the power source 4〇 is connected to the power pin 201. [0033] [0033] When the input terminal 1011 is at a low level, the second output terminal 1〇13 is also at a low level by the voltage division of the resistors R2 and R3. The selection circuit 1〇3 selects the Host D+ and Host D− pins of the processing unit 3〇 to be connected to the D+ and D− pins of the USB interface. Therefore, when the USB interface 20 is externally connected to the slave device, the electronic device 1 supplies power to the power pin 201, and the selection circuit 103 selects the Host D+ 'Host D pin of the processing unit 3〇 and the .D+ of the 5 Xuan USB pin. The D —~ pin is connected and the electronic device is in master mode. ^ [Simple description of the diagram] Figure 1 is a functional block diagram of an electronic device that can automatically switch between USB master and slave modes. FIG. 2 is a specific circuit diagram of the electronic device capable of automatically switching the USB master-slave mode shown in FIG. 1. [Main component symbol description] _ [0034] USB master-slave mode switching circuit 10 USB interface - 20 ~ Processing unit 30 Power supply 40 Master-slave selection trigger 101 Control unit 102 Circuit_. Form No. A0101 Page 11 of 18 0982049184- 0 098128644 201107991 Select Circuit 103 Switch Circuit 104 Power Pin 201 Data?丨 202 202 Master device control reference 302 Slave device control 301 pin External electronic device 2 Input terminal 1011 First output terminal 1012 Second output terminal 1013 Resistor R1/R2/R3/R4 NPN transistor Q1 Slave device control Device D+/ Master device control Host D+/ Foot Device D—Foot Host D — 098128644 Form No. A0101 Page 12 of 18 0982049184-0

Claims (1)

201107991 VII. Patent application scope: 1. An electronic device capable of automatically switching the mode of the USB master-slave device for switching the master-slave mode of an electronic device, the electronic device comprising a USB interface, a processing unit and a power source, The USB interface includes a power pin and a data pin, and the improvement is that the electronic device capable of automatically switching the USB master-slave mode further includes: a master-slave selection trigger circuit, including an input terminal, a first output terminal, and a second output end, the input end is connected to a power pin of the USB interface, and when the master-slave selection trigger circuit detects that the USB interface power supply pin connected to the input terminal is low level, determining the external electronic The device is a slave device and sends a main trigger signal through the first and second output terminals. When the master-slave selection trigger circuit detects that the USB interface power supply pin connected to the input terminal is high level « ;; v /:, :13⁄413⁄4 :Ϊ:· ·:··Γ·:..........:·.: , judge that the external electronic device is the master device, and the first and second outputs emit a slave trigger signal; Switch circuit Connected between the power supply of the electronic device and the USB power supply pin; a control unit is respectively connected to the first output end and the switch circuit, and is configured to receive a trigger signal outputted by the first output end, when the trigger signal is When the trigger signal is received, the switch control unit controls the switch unit to be turned off, and disconnects the power supply of the electronic device from the USB power pin. When the trigger signal is the main trigger signal, the control unit controls the switch unit to be turned on. The electronic device power supply powers the USB power pin; a selection circuit is coupled to the second output terminal for selecting a master-slave mode of the processing unit according to the trigger signal received from the second output terminal, when the trigger signal is When the slave signal is triggered, the slave device pin of the processing unit is connected to the USB data pin of the 098128644 form number A0101 page 13 / 18 pages 0992049184-0 201107991, the processing unit controls the electronic device to operate in the slave mode, When the trigger signal is the main trigger signal, the main device pin of the processing unit is connected to the USB data pin, where Unit controls the electronic device operates in the master mode. 2. The electronic device capable of automatically switching a USB master-slave mode as described in claim 1, wherein the master-slave selection trigger circuit comprises a first resistor, a second resistor, and a third resistor, the first a connection node of the resistor and the second resistor is an input end of the master-slave selection trigger circuit, and the first resistor is away from a first output end of the second resistor terminal as a master-slave selection trigger circuit, the second resistor and the first resistor The connection node of the three resistors is the second output terminal of the master-slave selection trigger circuit. 3. The electronic device capable of automatically switching the USB master-slave mode as described in claim 2, wherein the control unit is a high-level switch, including a control terminal, a first conductive terminal, and a second The control terminal is connected to the first output end of the master-slave selection trigger circuit, the first conductive terminal is grounded, and the second conductive terminal is connected to the switch unit. 4. The electronic device capable of automatically switching the USB master-slave mode as described in claim 3, wherein the switch circuit is a high-level switch, including a control terminal, a first conductive terminal, and a second a conduction end, the control end and the second conduction end of the switch, the first conduction end is connected to the power source, the second conduction end is connected to the USB power supply pin, wherein the control end of the switch unit further passes a fourth A resistor is connected to the power source. 5. The electronic device capable of automatically switching a USB master-slave mode as described in claim 4, wherein when the electronic device is connected to the host device, the host device provides a high level signal to the master-slave through the USB interface. Selecting an input terminal of the trigger circuit, the first output terminal passes the first resistor and the input terminal 098128644. Form number A0101 page 14 / 18 pages 0992049184-0 201107991 Ο 8. The connection thus also obtains a high level, the control terminal of the control unit is at a high level to cause the control unit to be turned on, and the control terminal of the switch circuit is at a low level through the conductive control unit being grounded, the switch The circuit is cut off; when the electronic device is connected to the host device, the input terminal is at a low level, so that the first output terminal connected to the input terminal through the first resistor is also at a low level, and the control end of the control unit is at a low level The low level causes the control unit to turn off. The control terminal of the switch circuit obtains a high level by connecting the fourth resistor to the power source, thereby causing the switch circuit to be turned on. The electronic device capable of automatically switching the USB master-slave mode, as described in claim 2, wherein the selection circuit is a double-pole double-throw switch circuit, including a control terminal, the control terminal and the master-slave selection trigger circuit The second output terminal is connected. When the control terminal receives the main trigger signal, the double-pole double-throw switch circuit connects the host USB data pin to the main device control pin of the processing unit, and when the control switch receives The slave double throw switch circuit connects the slave USB data pin to the slave data pin of the processing unit when the trigger signal is received. The electronic device capable of automatically switching the USB master-slave mode, as described in claim 6, wherein the processing unit operates in the master mode after the main control pin of the processing unit is connected to the USB data pin, that is, The electronic device is used as a master device, and the external electronic device connected through the USB data pin is used as a slave device. After the slave control pin of the processing unit is connected to the USB data pin, the processing unit operates in the slave device mode. That is, the electronic device is used as the slave device, and the external electronic device connected through the USB data pin is used as the master device. The electronic device capable of automatically switching the USB master-slave device mode as described in claim 3, wherein The control unit is an NM0S tube or an NPN three-pole 098128644 form number A0101 page 15 / 18 pages 0982049184-0 201107991 tube. 9. The electronic device capable of automatically switching the USB master-slave mode as described in claim 4, wherein the switch circuit is an NM0S tube or an NPN transistor 0 098128644 Form No. A0101 Page 16 of 18 0982049184- 0