CN210091164U

CN210091164U - Switching circuit and device

Info

Publication number: CN210091164U
Application number: CN201921136589.2U
Authority: CN
Inventors: 万春晖; 黄赤; 李建华
Original assignee: Shenzhen Lishun Diantong Technology Co Ltd
Current assignee: Shenzhen Lishun Diantong Technology Co Ltd
Priority date: 2019-07-18
Filing date: 2019-07-18
Publication date: 2020-02-18
Anticipated expiration: 2029-07-18

Abstract

A switching circuit and a switching device are provided, wherein an expansion module expands a USB interface of a main chip into a plurality of USB expansion ports. When the mobile terminal is in the first working mode, the switching module controls the USB interface of the main chip to be conducted with first external equipment, so that the first external equipment is used as main equipment to execute a carplay function; when the USB expansion port is in the second working mode, the switching module controls the USB expansion port to be communicated with the first external equipment, so that the first external equipment is used as slave equipment. When the switch module receives the first control signal, the expansion module is controlled to quit operation and the switching module is controlled to switch to the first working mode, and when the switch module receives the second control signal, the expansion module is controlled to work and the switching module is controlled to switch to the second working mode. According to the switching circuit and the switching device, the working state of the expansion module and the working mode of the switching module are controlled through the switch module, so that not only is USB interface expansion carried out on a main chip of a single USB interface, but also a carplay function is realized, the problem that the type selection of the main chip is limited is solved, and the cost is saved.

Description

Switching circuit and device

Technical Field

The utility model belongs to the technical field of the on-vehicle system, especially, relate to a switching circuit and device.

Background

At present, when a main chip of an on-vehicle system is selected, two options are available, the first option is to select the main chip with only one USB interface, but in this case, the USB interface must be used for USB interface expansion, that is, expansion into a plurality of USB interfaces capable of being connected to a plurality of slave devices such as a car data recorder, a USB disk, or a mobile phone, so that a user cannot use a carplay (an on-vehicle entertainment system developed by apple computer) function of the apple mobile phone on the on-vehicle system, resulting in poor user experience and low user viscosity. And secondly, selecting a main chip with a USB interface and an OTG interface, wherein the USB interface is used for expanding the USB interface, and the OTG interface is used for connecting an apple mobile phone to realize a carplay function, but the main chip of the type is expensive in manufacturing cost.

For the above reasons, the main chip of the vehicle-mounted system is limited in type selection, and the user needs to give up the display function of the iphone or select the main chip with higher cost. Therefore, it is necessary to develop a new circuit to solve the problem that the host chip of a single USB interface cannot implement both USB interface expansion and display functions.

SUMMERY OF THE UTILITY MODEL

In view of this, the embodiment of the present invention provides a switching circuit and a switching device, which aim to solve the problem that the main chip of a single USB interface cannot realize both USB interface expansion and display function.

The utility model provides a first aspect of the embodiment provides a switching circuit, include:

the expansion module is connected with a main chip of the vehicle-mounted system and used for expanding the USB interface of the main chip into a plurality of USB expansion ports;

a switching module, connected to any one of the USB expansion port and the USB interface of the main chip, and connected to a first external device, and configured to control the USB interface of the main chip to be conducted with the first external device when in a first operating mode, so that the first external device performs a carplay function as a main device, or control the USB expansion port to be conducted with the first external device when in a second operating mode, so that the first external device operates as a slave device; and

the expansion module is connected with the main chip, the expansion module and the switching module and is used for controlling the expansion module to quit operation and controlling the switching module to switch to the first working mode when the main chip outputs a first control signal; or when the main chip outputs a second control signal, the expansion module is controlled to work and the switching module is controlled to be switched to the switch module in the second working mode.

The above switching circuit; and

and the power supply module is connected with the expansion module and the switching module and is used for supplying power to the expansion module and the switching module.

A second aspect of the embodiments of the present invention provides a switching device, including:

according to the switching circuit and the switching device, the working state of the expansion module and the working mode of the switching module are controlled through the switch module, so that not only is USB interface expansion carried out on a main chip of a single USB interface, but also a carplay function is realized, the problem that the type selection of the main chip is limited is solved, and the cost is saved. The switching circuit and the switching device are connected with a main chip of the vehicle-mounted system, are used for expanding a USB interface of the main chip into a plurality of USB expansion ports, and can selectively execute a carplay function when the accessed external equipment is an apple mobile phone. Therefore, even if the main chip of the vehicle-mounted system only has a single USB interface, the functions of expanding the USB interface and executing the carplay can be realized by connecting the switching circuit, the problem of limited type selection of the main chip is solved, the user experience is good, and the user viscosity is high.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the embodiments or the prior art descriptions will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive labor.

Fig. 1 is a schematic diagram of a module structure of a switching circuit according to an embodiment of the present invention;

fig. 2 is a circuit diagram illustrating an example of the switching power shown in fig. 1.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1, a schematic diagram of a module structure of a switching circuit according to an embodiment of the present invention shows only parts related to the embodiment for convenience of description, and the detailed description is as follows:

a switching circuit comprises an expansion module 10, a switching module 30 and a switch module 20.

The switching circuit is connected with a main chip 100 of the vehicle-mounted system, and is used for expanding a USB interface H of the main chip into a plurality of USB expansion ports, and realizing that a carplay function can be selectively executed when the accessed external equipment is an apple mobile phone. Therefore, even if the main chip 100 of the vehicle-mounted system only has a single USB interface, the switching circuit can be connected to realize the expansion of the USB interface and the execution of the carplay function, so that the problem of limited type selection of the main chip 100 is solved, the user experience is good, and the user viscosity is high.

The expansion module 10 is connected to a main chip 100 of the vehicle-mounted system, and is configured to expand a USB interface H (indicated by H in fig. 1) of the main chip into a plurality of USB expansion ports.

Specifically, the main chip 100 with a single USB interface may be adopted, and the main chip 100 with dual USB interfaces or multiple USB interfaces may also be adopted. The plurality of USB expansion ports are respectively connected with external equipment. The USB interface H of the main chip is connected to the input port M of the expansion module 10.

Optionally, the expansion module 10 expands one USB interface of the main chip 100 into four USB expansion ports (indicated by A, B, C and D in fig. 1), and the four USB expansion ports can be respectively connected to one external device.

The USB interface H of the host chip, the USB expansion ports A, B, C and D of the expansion module 10, the input port M of the expansion module 10, and the interfaces E, F and G of the switching module 30, which are described below, are used for transmitting differential signals, so the ports A, B, C, D, E, F, G, H and M each include two signal terminals.

External devices include, but are not limited to, a vehicle event data recorder, a USB flash disk, a mobile phone, a tablet, and a mobile charger.

The switching module 30 is connected to any one of the USB expansion port and the USB interface H of the main chip, and is connected to a first external device (shown as external device 1 in fig. 1), and is configured to control the USB interface H of the main chip to be conducted with the first external device when in the first operating mode, so that the first external device performs a carplay function as the main device, or control the USB expansion port to be conducted with the first external device when in the second operating mode, so that the first external device operates as the slave device.

Specifically, the switch module 30 has two input ports (denoted by E and F in fig. 1) and one output port (denoted by G in fig. 1), the USB interface H of the main chip is connected to the input port E of the switch module 30, any one USB expansion port of the expansion module 10 is connected to the input port F, and fig. 1 only shows a case where the USB expansion port a is connected to the input port F.

When the switching module 30 is in the first operating mode, the input port E is turned on, the input port F is turned off, the USB interface H, the input port E, and the output port G of the main chip are communicated, and when the first external device that is accessed is an apple phone and the apple phone opens the carplay function, the apple phone performs the carplay function as the main device. At this time, The port G of The switching module 30 has an OTG (On-The-Go) function, and can perform role switching between The master device and The slave device for The two accessed devices.

When the switching module 30 is in the second operation mode, the input port E is turned off, the input port F is turned on,

the differential signal output by the USB interface H of the main chip is sequentially transmitted to the first external device after passing through the input port M of the expansion module 10, the output port a of the expansion module 10, the input port F of the switching module 30, and the output port G of the switching module 30, and at this time, the first external device operates as a slave device without executing a carplay function. When the switch module 30 is in the second operation mode, the output port G of the switch module 30 is equivalent to a USB expansion port, instead of the output port a of the expansion module 10.

The switch module 20 is connected to the main chip 100, the expansion module 10 and the switching module 30, and is configured to control the expansion module 10 to exit from operation and control the switching module 30 to switch to the first working mode when the main chip 100 outputs the first control signal; or when the main chip 100 outputs the second control signal, the expansion module 10 is controlled to operate and the switching module 30 is controlled to switch to the second operating mode.

Specifically, when the switch module 20 receives the first control signal output by the main chip 100, it is turned on; the switch module 20 is turned off when receiving the second control signal output from the main chip 100. The first control signal is a high level signal and the second control signal is a low level signal.

According to the switching circuit, the working state of the expansion module 10 and the working mode of the switching module 30 are controlled by the switch module 20, so that not only the USB interface expansion but also the carplay function of the main chip 100 with a single USB interface are realized, the problem that the type selection of the main chip 100 is limited is solved, and the cost is saved.

Fig. 2 is a circuit diagram of the exemplary switching circuit shown in fig. 1, which only shows the parts related to the present embodiment for convenience of description, and the details are as follows:

in an alternative embodiment, the expansion module 10 comprises an expansion unit 101 and a protection unit 102.

The expansion unit 101 is connected to the USB interface H of the main chip, and is configured to expand the USB interface H of the main chip into a plurality of USB expansion ports.

The protection unit 102 is connected to the extension unit 101 for preventing the extension unit 101 from being affected by static electricity.

The expansion unit 101 comprises a hub chip U1, a first resistor R1, a second resistor R2, a first capacitor C1, a second capacitor C2 and a crystal oscillator XT 1.

The protection unit 102 includes a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a first electrostatic protector ESD1, and a second electrostatic protector ESD 2.

In an alternative embodiment, the switch module 20 includes an NPN transistor Q1 and a third capacitor C3.

In an alternative embodiment, the switching module 30 includes a switching chip U2, a seventh resistor R7, an eighth resistor R8, and a third ESD protector 3.

In an optional embodiment, the switching circuit further includes an interface protection module 40, and the interface protection module 40 is connected to the USB interface H of the main chip, the expansion module 10 and the switching module 30, and is used for preventing a signal reflection phenomenon.

Specifically, during the high-speed transmission of signals, echoes easily appear on the transmission line, and part of the signals are reflected, so that the interface protection module 40 needs to be added to ensure that the source end and the load end have the same impedance, so as to avoid the occurrence of reflection.

In an alternative embodiment, the interface protection module 40 includes a ninth resistor R9 and a tenth resistor R10.

The following explains the connection relationship and the operation principle of the switch circuit in detail with reference to the exemplary circuit diagram of fig. 2:

the first differential input end DMP and the second differential input end DMU of the concentrator chip U1 are connected with the USB expansion port of the main chip 100; a level detection end VBUSM of the hub chip U1 is connected with a collector electrode of the NPN triode Q1; the first differential output end DP1 and the second differential output end DM1 of the hub chip U1 are respectively connected with a second positive input end HSD2+ and a second negative input end HSD 2-of the conversion chip U2; the third differential output terminal DP2 and the fourth differential output terminal DM2 of the hub chip U1 are connected to a second external device; the fifth differential output terminal DP3, the sixth differential output terminal DM3, the seventh differential output terminal DP4 and the eighth differential output terminal DM4 of the hub chip U1 are connected to the first end of the third resistor R3, the first end of the fourth resistor R4, the first end of the fifth resistor R5 and the first end of the sixth resistor R6.

The clock output terminal XIN of the hub chip U1, the first end of the first resistor R1 and the first end of the second resistor R2 are connected in common, the second end of the first resistor R1, the first end of the first capacitor C1 and the first end of the crystal oscillator XT1 are connected in common, the second end of the crystal oscillator XT1, the first end of the second capacitor C2 and the second end of the second resistor R2 are connected in common, and the second end of the second capacitor C2 is connected to ground.

A second end of the third resistor R3 is connected to a first input terminal of the first electrostatic protector ESD1, a second end of the fourth resistor R4 is connected to a second input terminal of the first electrostatic protector ESD1, a second end of the fifth resistor R5 is connected to a first input terminal of the second electrostatic protector ESD2, and a second end of the sixth resistor R6 is connected to a second input terminal of the second electrostatic protector ESD 2.

Specifically, the first differential input terminal DPU and the second differential input terminal DMU of the hub chip U1 are used together as the input port M of the expansion module 10 for receiving the differential signal output by the main chip 100. The terminal D90_ USB _ DP and the terminal D90_ USB _ DM shown in fig. 2 together serve as a USB interface H of the main chip for transmitting differential signals. The first differential output end DP1 and the second differential output end DM1 of the hub chip U1 are commonly used as the USB expansion port a of the expansion module 10; the third differential output end DP2 and the fourth differential output end DM2 of the hub chip U1 are commonly used as a USB expansion port B of the expansion module 10; the fifth differential output terminal DP3 and the sixth differential output terminal DM3 of the hub chip U1 are commonly used as the USB expansion port C of the expansion module 10, and the seventh differential output terminal DP4 and the eighth differential output terminal DM4 are commonly used as the USB expansion port D of the expansion module 10.

The third resistor R3 and the fourth resistor R4 are connected in series to the USB expansion port C of the expansion module 10, and the first electrostatic protector ESD1 is connected in parallel to the USB expansion port C, and is used for guiding the static electricity on the signal line to the ground. The fifth resistor R5 and the sixth resistor R6 are connected in series to the USB expansion port D of the expansion module 10, and the second electrostatic protector ESD2 is connected in parallel to the USB expansion port D, and is used for guiding the static electricity on the signal line to the ground.

A first positive input end HSD1+ of the conversion chip U2 and a first negative input end HSD 1-of the conversion chip U2 are connected with the USB interface H of the main chip, a positive output end D + of the conversion chip U2 is connected with a first end of a seventh resistor R7, a second end of the seventh resistor R7 is connected with a first input end of a third electrostatic protector ESD3, a negative output end D-of the conversion chip U2 is connected with a first end of an eighth resistor R8, and a second end of the eighth resistor R8 is connected with a second input end of a third electrostatic protector ESD 3; the output of the third electrostatic protector ESD3 is grounded.

Output enable terminal of conversion chip U2The input selection terminal S of the conversion chip U2 is connected to the collector of the NPN transistor Q1.

Specifically, the first positive input terminal HSD1+ of the converting chip U2 and the first negative input terminal HSD 1-of the converting chip U2 collectively serve as the input port E of the switching module 30; the second positive input terminal HSD2+ of the converting chip U2 and the second negative input terminal HSD 2-of the converting chip U2 are collectively used as the input port F of the switching module 30; the positive output terminal D + of the converting chip U2 and the negative output terminal D-of the converting chip U2 are used together as the output port G of the switching module 30.

When the input selection terminal S is in a high level state, the input port E of the conversion chip U2 is turned on, and the input port F is turned off; when the input select terminal S is in a low state, the input port E of the switch chip U2 is turned off, and the input port F is turned on.

Fig. 2 shows access ports of the first external device by using OTG _ DP1 and OTG _ DM1, through which the first external device is connected to the output port G of the conversion chip U2.

The seventh resistor R7 and the eighth resistor R8 are connected in series with the output port G of the conversion chip U2, and the third electrostatic protector ESD3 is connected in parallel with the output port G, so that static electricity generated on a signal line is led to the ground, and the conversion chip U2 is protected from electrostatic damage.

The base electrode of the NPN triode Q1 is connected with the control end NRST _ USB of the main chip 100, and the emitting end of the NPN triode Q1 is grounded; a first terminal of the third capacitor C3 is connected to the collector of the NPN transistor Q1, and a second terminal of the third capacitor C3 is grounded.

Specifically, the base of the NPN triode Q1 serves as a controlled terminal, and receives a first control signal or a second control signal output by the control terminal NRST _ USB of the main control chip, where the first control signal is a high level signal and the second control signal is a low level signal. When receiving the first control signal, the NPN transistor Q1 is turned on, the level detection terminal VBUSM of the hub chip U1 is set high, the hub chip U1 does not operate, and the input selection terminal S of the conversion chip U2 is set high, so that the input port E is turned on, and the input port F is turned off; when receiving the second control signal, the NPN transistor Q1 turns off, the level detection terminal VBUSM of the hub chip U1 is set low, the hub chip U1 operates, and the input selection terminal S of the conversion chip U2 is set low, so that the input port F is turned on and the input port E is turned off.

Optionally, in an initial state after the vehicle-mounted system is started, the first control signal is output.

The first end of the ninth resistor R9 and the first end of the tenth resistor R10 are connected with the USB interface H of the main chip; the second terminal of the ninth resistor R9 is connected to the first differential input terminal DPU of the hub chip U1 and the first positive input terminal HSD1 of the conversion chip U2, and the second terminal of the tenth resistor R10 is connected to the second differential input terminal DMU of the hub chip U1 and the first negative input terminal HSD 1-of the conversion chip U2.

A second aspect of the embodiments provides a switching device, including foretell switching circuit, still include and be connected with extension module 10 and switching module 30 for to extension module 10 with switching module 30 carries out the power module of supplying power.

To sum up, the utility model provides a switching circuit and device through the operating condition of switch module control extension module and the mode of switching module, has realized not only carrying out the USB interface extension but also realizing carplay function to the main chip of single USB interface, has solved the limited problem of main chip lectotype, practices thrift the cost. The switching circuit and the switching device are connected with a main chip of the vehicle-mounted system, are used for expanding a USB interface of the main chip into a plurality of USB expansion ports, and can selectively execute a carplay function when the accessed external equipment is an apple mobile phone. Therefore, even if the main chip of the vehicle-mounted system only has a single USB interface, the functions of expanding the USB interface and executing the carplay can be realized by connecting the switching circuit, the problem of limited type selection of the main chip is solved, the user experience is good, and the user viscosity is high.

Various embodiments are described herein for various circuits and devices. Numerous specific details are set forth in order to provide a thorough understanding of the overall structure, function, manufacture, and use of the embodiments as described in the specification and illustrated in the accompanying drawings. However, it will be understood by those skilled in the art that the embodiments may be practiced without such specific details. In other instances, well-known operations, components and elements have been described in detail so as not to obscure the embodiments in the description. It will be appreciated by those of ordinary skill in the art that the embodiments herein and shown are non-limiting examples, and thus, it can be appreciated that the specific structural and functional details disclosed herein may be representative and do not necessarily limit the scope of the embodiments.

In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

The above description is only exemplary of the present invention and should not be construed as limiting the present invention, and any modifications, equivalents and improvements made within the spirit and principles of the present invention are intended to be included within the scope of the present invention.

Claims

1. A switching circuit, comprising:

2. The switching circuit of claim 1, wherein the expansion module is further to implement electrostatic protection, the expansion module comprising:

the extension unit is connected with the USB interface of the main chip and used for extending the USB interface of the main chip into a plurality of USB extension ports; and

and the protection unit is connected with the extension unit and used for preventing the extension unit from being influenced by static electricity.

3. The switching circuit of claim 2, wherein the extension unit comprises:

the concentrator comprises a concentrator chip, a first resistor, a second resistor, a first capacitor, a second capacitor and a crystal oscillator;

the first differential input end and the second differential input end of the concentrator chip are connected with the USB expansion port of the main chip; the level detection end of the concentrator chip is connected with the switch module; the first differential output end and the second differential output end of the concentrator chip are connected with the switching module; the third differential output end and the fourth differential output end of the concentrator chip are connected with second external equipment; a fifth differential output end, a sixth differential output end, a seventh differential output end and an eighth differential output end of the concentrator chip are connected with the protection unit;

the clock output end of the concentrator chip, the first end of the first resistor and the first end of the second resistor are connected in common, the second end of the first resistor, the first end of the first capacitor and the first end of the crystal oscillator are connected in common, the second end of the crystal oscillator, the first end of the second capacitor and the second end of the second resistor are connected in common, and the second end of the second capacitor is grounded.

4. The switching circuit of claim 3, wherein the protection unit comprises:

the first electrostatic protector comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first electrostatic protector and a second electrostatic protector;

the first end of the third resistor, the first end of the fourth resistor, the first end of the fifth resistor and the first end of the sixth resistor are respectively connected with the fifth differential output terminal, the sixth differential output terminal, the seventh differential output terminal and the eighth differential output terminal; the second end of the third resistor is connected with the first input end of the first electrostatic protector, the second end of the fourth resistor is connected with the second input end of the first electrostatic protector, the second end of the fifth resistor is connected with the first input end of the second electrostatic protector, and the second end of the sixth resistor is connected with the second input end of the second electrostatic protector.

5. The switching circuit of claim 1, wherein the switch module comprises:

an NPN triode and a third capacitor;

the base electrode of the NPN triode is connected with the control end of the main chip, and the collector electrode of the NPN triode is connected with the extension module and the switching module; the emitting end of the NPN triode is grounded; the first end of the third capacitor is connected with the collector of the NPN triode, and the second end of the third capacitor is grounded.

6. The switching circuit of claim 1, wherein the switching module comprises:

the circuit comprises a conversion chip, a seventh resistor, an eighth resistor and a third electrostatic protector;

the first positive input end of the conversion chip and the first negative input end of the conversion chip are connected with the USB interface of the main chip, the second positive input end of the conversion chip and the second negative input end of the conversion chip are connected with any one of the USB expansion ports, the positive output end of the conversion chip is connected with the first end of the seventh resistor, the second end of the seventh resistor is connected with the first input end of the third electrostatic protector, the negative output end of the conversion chip is connected with the first end of the eighth resistor, and the second end of the eighth resistor is connected with the second input end of the third electrostatic protector; the output end of the third electrostatic protector is grounded;

the output enabling end of the conversion chip is grounded, and the output selecting end of the conversion chip is connected with the switch module.

7. The switching circuit of claim 1, further comprising:

the interface protection module is connected with the USB interface of the main chip, the expansion module and the switching module and used for preventing signal reflection.

8. The switching circuit of claim 7, wherein the interface protection module comprises:

a ninth resistor and a tenth resistor;

the first end of the ninth resistor and the first end of the tenth resistor are connected with the USB interface of the main chip; the second end of the ninth resistor is connected with the expansion module and the switching module, and the second end of the tenth resistor is connected with the expansion module and the switching module.

9. The switching circuit of claim 1, wherein the first control signal is a high level signal and the second control signal is a low level signal.

10. A switching device, comprising:

the switching circuit of any one of claims 1 to 9; and