USB signal switch circuitry using standard USB hub and method of operation the same

A universal serial bus (USB) apparatus that has a USB hub, a first switching unit including first end coupled to a USB peripheral port of a first device, a second switching unit including a second end coupled to the USB hub and the first switching unit and a first end configured to be coupled to a first USB device, and control circuitry operable to provide control signals to the first and second switching units, in which the first control signals cause the first and second switching units to provide connectivity between the USB peripheral port of the first device and the first USB device when the first USB device is operating as a USB host and the second control signals to provide connectivity between the USB host port to the first USB device via the USB hub when the first USB device is operating as a USB peripheral.

TECHNICAL FIELD

The present disclosure relates generally to universal serial bus (USB) devices and systems. More particularly, it relates to USB signal path control and port switching embodiments using a standard USB hub and switch circuitry, and methods of operation thereof.

BACKGROUND

The USB standard is an easy-to-use universal interface for electronic devices, such as personal computer (PC), tablets, hubs, smartphones, etc., that has gained widespread acceptance. It is getting more prevalent to incorporate USB connections to automobile infotainment systems for power delivery purposes and interaction with mobile electronic devices, such as smartphones. In embodiments, the infotainment system may assume the role of a USB host while connecting to a mobile electronic device. In some embodiments, mobile electronic devices, such as an iPhone®, may assume a USB host role and controls at least an in-dash vehicle display portion of the infotainment system. Therefore, there are needs for a USB hub and switching logic circuit to allow an electronic system or device, such as an infotainment system, to connect to both USB peripheral device(s) and USB host device(s) concurrently.

DETAILED DESCRIPTION

The following description sets forth numerous specific details such as examples of specific systems, components, methods, and so forth, in order to provide a good understanding of several embodiments of the subject matter. It will be apparent to one skilled in the art, however, that at least some embodiments may be practiced without these specific details. In other instances, well-known components or methods are not described in detail or are presented in a simple block diagram format in order to avoid unnecessarily obscuring the techniques described herein. Thus, the specific details set forth hereinafter are merely exemplary. Particular implementations may vary from these exemplary details and still be contemplated to be within the spirit and scope of the subject matter.

Unless specifically stated otherwise, as apparent from the following discussions, it is appreciated that throughout the specification discussions utilizing terms such as “generating”, “detecting”, “processing”, “computing”, “calculating”, “determining”, or the like, refer to the action and/or processes of a computer or computing system, or similar electronic computing device, that manipulate and/or transform data represented as physical, such as electronic, quantities within the computing system's registers and/or memories into other data similarly represented as physical quantities within the computing system's memories, registers or other such information storage, transmission or display devices. Various units, circuits, or other components may be described or claimed as “configured to” or “configurable to” perform a task or tasks. In such contexts, the phrase “configured to” or “configurable to” is used to connote structure by indicating that the units/circuits/components include structure (e.g., circuitry) that performs the task or tasks during operation. As such, the unit/circuit/component can be said to be configured to perform the task, or configurable to perform the task, even when the specified unit/circuit/component is not currently operational (e.g., is not on). The units/circuits/components used with the “configured to” or “configurable to” language include hardware—for example, circuits, memory storing program instructions executable to implement the operation, etc. Reciting that a unit/circuit/component is “configured to” perform one or more tasks, or is “configurable to” perform one or more tasks, is expressly intended not to invoke 35 U.S.C. 112, sixth paragraph, for that unit/circuit/component. Additionally, “configured to” or “configurable to” can include generic structure (e.g., generic circuitry) that is manipulated by software and/or firmware (e.g., an FPGA or a general-purpose processor executing software) to operate in manner that is capable of performing the task(s) at issue. “Configured to” may also include adapting a manufacturing process (e.g., a semiconductor fabrication facility) to fabricate devices (e.g., integrated circuits) that are adapted to implement or perform one or more tasks. “Configurable to” is expressly intended not to apply to blank media, an unprogrammed processor or unprogrammed generic computer, or an unprogrammed programmable logic device, programmable gate array, or other unprogrammed device, unless accompanied by programmed media that confers the ability to the unprogrammed device to be configured to perform the disclosed function(s).

SUMMARY OF SUBJECT MATTER

The examples, implementations, and embodiments described herein may provide signal path switching and port swapping to USB apparatus and systems, and methods of operation thereof.

According to one embodiment, an USB apparatus of the subject matter may include a USB hub that has an upstream port coupling to a USB host port of a first device and a plurality of downstream ports, a first switching unit that has first and second ends, in which the first end is coupled to a USB peripheral port of the first device, a second switching unit that has a second end coupled to a first downstream port of the USB hub and the second end of the first switching unit. The second switching unit further has a first end configured to be coupled to a first USB device, and control circuitry operable to provide first control signals to the first and second switching units. In one embodiment, the first control signals may cause the first and second switching units to provide connectivity between the USB peripheral port of the first device and the first USB device when the first USB device is operating as a USB host. In one embodiment, it may also provide second control signals to at least the second switching unit, in which the second control signals may cause the second switching unit to provide connectivity between the USB host port to the first USB device via the first downstream port of the USB hub when the first USB device is operating as a USB peripheral.

In one embodiment, the aforementioned USB apparatus may also include a third switching unit that has a second end coupled to a second downstream port of the USB hub and the second end of the first switching unit, and a first end configured to be coupled to a second USB device.

In one embodiment, the control circuitry may be operable to provide third control signals to the first and third switching units, in which the third control signals may cause the first and third switching units to provide connectivity between the USB peripheral port of the first device and the second USB device when the second USB device is operating as a USB host. In another embodiment, the control circuitry may be operable to provide fourth control signals to at least the third switching unit, in which the fourth control signals may cause the third switching unit to provide connectivity between the USB host port of the first device to the second USB device via the second downstream port of the USB hub when the second USB device is operating as a USB peripheral.

In one embodiment, the control circuitry may have USB device functions and be coupled to a third downstream port of the USB hub. The control circuitry may be configured to receive USB signal commands from the first device through the USB host port and the USB hub.

In another embodiment, the control circuitry may be coupled to the first USB device through a serial interface.

In another embodiment, the control circuitry may be a part of the first device.

In one embodiment, the first and/or second and/or switching units are configured to multiplex USB D+/D− signals.

In one embodiment, each of the first, second, and third switching units may have a two input to two output (2×2) USB 2.0 switch.

In one embodiment, the USB peripheral port of the first device may be a USB On-The-Go (OTG) port and the first USB device may be an OTG device.

In one embodiment, the first USB device may be coupled to the first device through a USB Type-C receptacle.

According to one embodiment, a method of operation of a USB device/system of the subject matter may include the steps of coupling a USB peripheral port of a first device to a first USB device through a first switching unit and a second switching unit to establish a first signal path, coupling a USB host port of the first device to the first USB device through a USB hub and the second switching unit to establish a second signal path, disconnecting the USB hub and the first USB device, using the second switching unit, to deactivate the second signal path when the first USB device is operating as a USB host, and activating the first signal path, using the first and second switching units when the first USB device is operating as a USB host.

In one embodiment, the aforementioned method may also include the steps of coupling the USB peripheral port of the first device to a second USB device through the first and a third switching units to establish a third signal path, coupling the USB host port of the first device to the second USB device through the USB hub and the third switching unit to establish a fourth signal path, disconnecting the USB hub and the second USB device, using the third switching unit, to deactivate the fourth signal path when the second USB device is operating as a USB host, and activating the third signal path, using the first and third switching units when the second USB device is operating as a USB host.

In one embodiment, the second signal path and the third signal path may be configured to be activated concurrently when the first device is operating as a USB host to the first USB device and a USB peripheral to the second USB device.

In another embodiment, the first signal path and the fourth signal path may be configured to be activated concurrently when the first device is operating as a USB peripheral to the first USB device and a USB host to the second USB device.

In one embodiment, the aforementioned method may also include the steps of transmitting control signals, from control circuitry, to the first and second switching units, in which the control signals are configured to cause the second switching unit to disconnect the USB hub to the first USB device. The control signals may also cause the first and second switching units to connect the USB peripheral port of the first device to the first USB device, when the first USB device is operating as the USB host.

According to one embodiment, a USB system of the subject matter may include a head unit of an automobile infotainment system that may have a USB host port and a USB peripheral port, a USB hub that has an upstream port coupled to the USB host port, switching circuitry that is configured to switch and multiplex USB D+/D− signals, control circuitry that is configured to transmit control signals to the switching circuitry, and a vehicle center console including first and second USB Type-C ports. In one embodiment, when a first USB device is operating as a USB host and coupled to the first USB Type-C port, the control signals may be configured to cause the switching circuitry to disconnect the USB hub and the first USB device and to enable connection between the USB peripheral port and the first USB device.

In one embodiment, the first USB device may be an Apple® iPhone® that is CarPlay® enabled and the USB peripheral port of the head unit may be a USB On-The-Go (OTG) port.

In one embodiment, the switching circuitry may include first, second, and third signal repeaters, in which the first signal repeater may be coupled to the USB peripheral port and the second and third signal repeaters may each be coupled to one of downstream ports of the USB hub and the first signal repeater. In one embodiment, the first, second, and third signal repeaters may each include a two input to two output (2×2) USB 2.0 switch.

In another embodiment, the switching circuitry may have a two input to three output (3×2) USB 2.0 switch, in which USB D+/D− top signals and USB D+/− bottom signals coupled to the first USB type C port may be shorted to form a first D+/D− input, and USB D+/D− top signal and USB D+/D− bottom signal coupled to the second USB type C port may be shorted to form a second D+/D− input. In one embodiment, two D+/D− outputs of the 3×2 USB 2.0 switch may be coupled to the USB hub and the last one D+/D− output to the USB peripheral port of the head unit.

In one embodiment, when a second USB device is operating as a USB peripheral and coupled to the second USB Type-C port, the control signals may be configured to cause the switching circuitry to enable connection between the USB host port and the second USB device through the USB hub.

In another embodiment, when a second USB device is operating as a USB host and coupled to the second USB Type-C port, the control signals may be configured to cause the switch circuitry to enable connection between the USB peripheral port and the second USB device.

In one embodiment, the head unit may operate as a USB peripheral to the first USB device and a USB host to the second USB device, or vice versa, concurrently and individually.

FIG. 1is a schematic diagram illustrating a USB hub in accordance with one embodiment of the subject matter. A USB hub is a device that expands a single USB port into several so that more ports are available to connect devices to a host system. In one embodiment, USB hub100may include USB hub logic104, upstream universal transceiver macrocell interface (UTMI) transceiver102a, and downstream UTMI transceivers102bto102d. USB hub logic104may be coupled to upstream UTMI transceiver102aon an upstream end and coupled to multiple downstream UTMI transceivers102bto102don a downstream end. In some embodiment, upstream UTMI transceiver102amay be coupled to a hosting device/system via an upstream receptacle (not shown) and downstream UTMI transceivers102bto102dmay be coupled to peripheral device(s) via downstream receptacles (not shown), respectively. In other embodiments, transceivers using logic level signals other than UTMI may be used. In one embodiment, a downstream port power management circuit (not shown) may also be coupled between USB hub logic104and downstream receptacles. It will be the understanding that the shown configuration of USB hub100inFIG. 1and the numbers of upstream and downstream ports are for illustrative purposes, and not to be construed as limitations. Upstream and downstream UTMI transceivers102ato102dmay provide a physical layer interface (PHY) between USB signaling on USB interfaces and logic signaling used inside USB hub logic104. For example, upstream and downstream UTMI transceivers102ato102dmay provide an interface between the D+ and D− USB signals from host or peripheral devices and the 8 or 16 bit UTMI logic signal buses connected to USB hub logic104. The control and operation of USB hub100may be implemented using control logic, digital circuitry, analog circuitry, and a processor, microcontroller, state machine, or other execution unit. The instructions, when loaded into memory and executed by the processor, may cause or configure USB hub100to perform the functionality described herein. The processor, control logic, and circuitry may be included in USB hub logic104. USB hub logic104may determine how USB communication is to be performed by USB hub100.

In general, a standard USB hub, such as USB hub100, may be configured to allow multiple USB peripheral devices (via downstream ports) to be coupled and controlled by a single host device/system (via an upstream port). With continual upgrades and improvements, many USB devices, such as mobile phones, tablets, digital audio players, cameras, etc., may act as a host or a peripheral device in different occasions. A standard USB hub, such as USB hub100, however may not support such reversal or swapping of host/peripheral roles in its configuration.

FIG. 2is a schematic diagram illustrating an electronic system that supports the USB standards, such as USB 2.0, USB 3.0, USB 3.1, USB Type-C, and USB On-The-Go (OTG). In one embodiment, the electronic system inFIG. 2may be a head unit200of an infotainment system in an automobile. Head unit200may include a CPU202coupled to USB host control logic206and USB peripheral control logic208. USB host control logic206is further coupled to USB host port210and USB peripheral control logic208to USB peripheral port212. In one embodiment, head unit200may act as a USB host when being coupled to a peripheral device (such as an MP3 player) via USB host port210. In one embodiment, USB host control logic206may control data link wherein data is broadcasted to and received from connected USB peripheral device(s). In another embodiment, head unit200may act as a USB peripheral device when being coupled to a device that has the capabilities of serving as a USB host via USB peripheral port212. For example, head unit200may be coupled to a smart phone (not shown), in which the smart phone may control an in-dash vehicle display, such as display204of head unit200. USB peripheral control logic208may provide control of data received and transmitted to the smart phone via USB peripheral port212. In one embodiment, head unit200may assume the role of a USB host device and a USB peripheral device concurrently, and each of the USB host and peripheral operation may be executed individually. It will be the understanding that head unit200is only one example of the electronic system illustrated inFIG. 2. The electronic system inFIG. 2may be any device or system, such as a personal computer, a monitor, a smart phone, that has the capabilities and needs to be a USB host and a USB peripheral device concurrently, such as a USB OTG device.

FIG. 3is a schematic diagram illustrating a USB system in accordance with one embodiment of the subject matter. In one embodiment, USB system300may include head unit302of an automobile that is similar to head unit200inFIG. 2. Head unit302may have USB host port310and USB peripheral port308, which are separated from one another. In one embodiment, USB peripheral port308may be, additionally or alternatively, a USB OTG port. The USB OTG Specification enables USB peripheral devices to assume the role of a USB host as required and hence be able to take more control of the USB data flow, but the OTG model requires that the default host, such as head unit302, change to a USB peripheral role concurrently as the device changing to the USB host role. In one embodiment, head unit302is coupled to several USB devices306ato306dvia USB control and switch device304. USB control and switch device304may have USB Type-C receptacles308ato308dfor coupling to USB devices306ato306d, respectively. In other embodiments, one or more of receptacles308ato308dmay be USB Type-A receptacles, or other types of USB receptacles. USB devices306ato306dmay be a USB host device or a USB peripheral device or an USB OTG device. As an example, USB device306amay be a USB peripheral device. In one embodiment, USB control and switch device304may provide active signal path or communication link between head unit302and USB device306avia USB host port310. In this particular instance, USB control and switch device304may perform like a standard USB hub, such as USB hub100inFIG. 1. In another embodiment, USB device306bmay be a USB host device coupled to USB control and switch device304via receptacle308b. In this instance, USB control and switch device304may provide active signal path or communication link between head unit302and USB device306bvia USB peripheral port308, such that USB device306bmay assume control over one or more aspects of head unit302functionality and the established signal path. In one embodiment, USB control and switch device304may provide appropriate active signal paths to the connected USB devices306ato306d, according to the USB role (host or peripheral) they assume. In another embodiment, USB control and switch device304may have the abilities to provide signal path switching functions when a connected USB device, such as USB device306aswitching its role from a peripheral device to a host device, and vice versa. Details of USB control and switch device304are discussed below.

FIGS. 4A to 4Care representative block diagrams illustrating signal path switching using a USB hub according to one embodiment of the subject matter. Referring toFIG. 4A, infotainment head unit402may have USB host port404and USB peripheral port406. In one embodiment, USB peripheral port406may support USB OTG standards. Vehicle center console412may have several receptacles for coupling to USB devices. In embodiments, receptacles may be USB Type-C or other types of USB receptacles. When USB peripheral devices410aand410bare coupled to USB ports or receptacles in vehicle center console412, head unit402may assume the role of a USB host and an active signal path is established between USB host port404and the upstream port of USB hub408. USB hub408may then be coupled to USB peripheral devices410aand410bvia its downstream ports and USB receptacles in vehicle center console412. It will be understood that only two downstream ports and USB devices are shown inFIGS. 4A and 4Cfor illustrative purposes only. The numbers of downstream ports, receptacles, and USB devices may change according to system and usage requirements without departing from the broader spirit and scope of the disclosure.

Referring toFIG. 4B, USB host device412ais coupled to the left receptacle of vehicle center console412and USB peripheral device410cto the right receptacle. In one embodiment, USB host device412amay be a smart phone, such as an Apple iPhone®, or a device having USB host capabilities, or a USB OTG device. In one embodiment, a first signal path may be established between USB host port404of head unit402via USB hub408. Head unit402is the USB host of the communication link to USB peripheral device410c. Concurrently, a second signal path may be established between head unit402and USB host device412a. In one embodiment, the second signal path is a point-to-point link bypassing USB hub408and the communication link is controlled by USB host device412a. In one embodiment, there are two hosts in the system inFIG. 4B, one being included in head unit402controlling the first signal path to USB peripheral device410cvia USB hub408. The other host is USB host device412acontrolling the second signal path to USB peripheral port406of head unit402. In the embodiment that USB host device412ais a USB OTG device, USB peripheral port406may also be an OTG port, an additional signal path (not shown) that is known in the art may be present to enable and support OTG role swapping between head unit402and USB host device412a.

Referring toFIG. 4C, USB peripheral device410dis coupled to the left receptacle and USB host device412bor a USB OTG device is coupled to the right receptacle. In one embodiment, similar to the embodiment inFIG. 4B, a point-to-point signal path bypassing USB hub408may be established between USB peripheral/OTG port406of head unit402and USB host device412b. A host signal path may be established between USB host port404and USB peripheral device410dvia USB hub408. In one embodiment, both signal paths may be operational uninterrupted concurrently and individually, and head unit402may assume the roles of a USB host and a USB peripheral at the same time.

As illustrated inFIGS. 4A to 4C, for a USB system having a standard USB hub to operate as described, it may require dedicated USB peripheral and host ports at vehicle center console412, or unplugging of USB cables. In another embodiment, it may require rearrangement of signal paths to accommodate all three embodiments inFIGS. 4A to 4C.

FIGS. 5A to 5Care representative block diagrams illustrating USB systems according to embodiments of the subject matter. Referring toFIG. 5A, head unit502may be a part of an in-vehicle infotainment system or a device having both USB host and peripheral capabilities and compatibilities. In one embodiment, head unit502may have separate USB host port526and USB peripheral port522, which may additionally or alternatively be an OTG port. Head unit502may be coupled to USB hub504and switching circuit520that may perform similar functions to USB control and switch device304inFIG. 3. In one embodiment, USB hub and switching circuit520may include USB hub504having upstream port518and downstream ports520ato520c. USB hub504may be a standard USB hub having similar structural features and functions as USB hub100inFIG. 1, or other embodiments practiced in the art. In one embodiment, upstream port518and downstream ports520ato520cprovide a physical layer interface between USB D+/D− signaling to UTMI (or other analogous) signaling inside USB hub504. In one embodiment, USB host port526of head unit502is coupled to upstream port518of USB hub for USB D+/D− signal transmission. Downstream port520ais coupled to the multiple input/output end of first switching unit or signal repeater or multiplexer (hereinafter “signal repeater”)518while downstream port520cis coupled to the multiple input/output end of second signal repeater516. USB peripheral port522of head unit502is coupled to the single input/output end of third signal repeater514. Third signal repeater514is then coupled to the multiple input/output end of each of first and second signal repeater at their respective multiple input/output end. In one embodiment, first, second, and third signal repeaters518,516, and514may have similar structural features, and they may be multiplexers, passive Double-Pole-Double-Throw (DPDT) switches, active D+/D− signal repeaters, or a combination thereof. The primary function of first, second, and third signal repeaters518,516, and514is to switch, multiplex, and/or repeat input/output signal to/from one of the multiple signal paths as configured by control signals by multiplexing or switching the USB D+/D− signals. In embodiments, first, second, and third signal repeaters518,516, and514may be 1×2 USB 2.0 switches or 2×2 USB 2.0 switches for Type-C connection, which will be discussed in detail below. In one embodiment, control circuit506is coupled to downstream port520band transmits control signals to each of first, second, and third signal repeaters518,516, and514to configure active signal path(s). Control circuit506may be a USB device, including a USB peripheral controller function, receiving USB commands from head unit502through USB host port526and USB hub504. Single input/output ends of first and second signal repeaters518and516are coupled to receptacles situated in vehicle center console508. Vehicle center console508may include USB receptables524aand524bfor coupling to USB device(s)510and/or512. In embodiments, USB receptacles524aand524bmay be USB Type-C receptacles, USB Type-A receptacles, or other USB type receptacles.

Referring toFIG. 5A, USB devices510and512may be coupled to receptacles situated in vehicle center console508. In one embodiment, USB devices510and512may be both USB peripheral devices. Head unit502may start enumeration process and identify both USB devices510and512are USB peripheral devices, and may assume the USB host role. USB commands may be sent from head unit502to control circuit506through USB hub504and downstream port520b, which in response may then send control signals respectively to first, second, or third signal repeaters518,516, or514. In one embodiment, USB peripheral port522may be deactivated or disconnected. Additionally or alternatively, third signal repeater514may be deactivated by the control signal such that there is no active signal path from/to USB peripheral port522. First and second signal repeaters518and516may be configured, by control signals, to switch or repeat or multiplex USB D+/D− signals to and from downstream ports520aand520c, respectively. As a result, two respective active signal paths, as indicated in dotted lines inFIG. 5A, are established between USB host port526, and USB devices510and512. In one embodiment, head unit502may assume the USB host role and control the established communication links and/or USB devices510and512. In one alternative embodiment, only one USB device510or512is connected to a receptacle situated in vehicle center console508. Control circuit506may deactivate second or first signal repeater516or518. In one embodiment, signal repeaters514,516, and518may support multiplexing/repeating LS, FS, HS, and SS USB D+/D− signals up to at least 480 MHz speed while meeting the demanding timing and matching requirements of the USB specifications. It will be understood that only two active signal paths (to/from USB devices510and512) are included for simplicity, and should not be construed as limitations. Embodiments with more than two ports/receptacles in vehicle center console508will be discussed below.

In one embodiment, first, second, and third signal repeaters518,516, and514, and control circuit506may be integrated into a single integrated circuit (IC), and mounted on a circuit board along with USB hub504IC in vehicle center console508of the vehicle, or elsewhere in the vehicle (not shown). One USB cable may connect upstream port518of USB hub504to head unit502which may be in the dash board. Another USB cable may connect the single IC to peripheral/OTG port522of the head unit502. In one embodiment, these two USB cables may share a single insulating sleeve, and thus physically appear to be a single cable. Within the shared sleeve, there may be two sets of conductors, each with its own shield, though in some embodiments the two sets of conductors may share power and/or ground conductors. Receptacles524aand524bmay be USB Type-C receptacles. USB Type-C, is defined in various releases and/or versions of the USB Type-C specification (e.g., such as Release 1.0 dated Aug. 11, 2014, Release 1.1 dated Apr. 3, 2015, etc). The USB Type-C specification defines Type-C receptacle, Type-C plug, and Type-C cables that can support USB communications as well as power delivery over newer USB power delivery protocols defined in various revisions/versions of the USB-PD specification. Examples of USB Type-C functions and requirements may include, without limitation, data and other communications according to USB 2.0 and USB 3.0/3.1, electro-mechanical definitions and performance requirements for Type-C cables, electro-mechanical definitions and performance requirements for Type-C receptacles, electro-mechanical definitions and performance requirements for Type-C plugs, requirements for Type-C to legacy cable assemblies and adapters, requirements for Type-C-based device detection and interface configuration, requirements for optimized power delivery for Type-C connectors, etc. According to the USB Type-C specification(s), a Type-C port provides VBUS, D+, D−, GND, SSTX+, SSTX−, SSRX+, and SSRX− lines, among others. In addition, a Type-C port also provides a Sideband Use (denoted SBU) line for signaling of sideband functionality and a Configuration Channel (denoted CC) line for discovery, configuration, and management of connections across a Type-C cable. A Type-C port may be associated with a Type-C plug and/or a Type-C receptacle. For ease of use, the Type-C plug and the Type-C receptacle are designed as a reversible pair that operates regardless of the plug-to-receptacle orientation. Thus, a standard USB Type-C connector, disposed as a standard Type-C plug or receptacle, provides pins for four VBUS lines, four ground return (GND) lines, two D+ lines (DP1 and DP2), two D− lines (DN1 and DN2), two SSTX+ lines (SSTXP1 and SSTXP2), two SSTX− lines (SSTXN1 and SSTXN2), two SSRX+ lines (SSRXP1 and SSRXP2), two SSRX− lines (SSRXN1 and SSRXN2), two CC lines (CC1 and CC2), and two SBU lines (SBU1 and SBU2), among others.

Referring toFIG. 5B, a similar USB system550to USB system500is featured. In one embodiment, USB host device510′ and USB peripheral device512may be coupled to receptacles524aand524bsituated in vehicle center console508, respectively. During the USB enumeration process, USB host port526in head unit502may identify the device (USB host device510′) coupled to USB receptacle524aas being capable of USB host operation. In one embodiment, head unit502may send USB command signals through USB host port526to control circuit506via USB hub504. In turn, control circuit506may send a control signal to signal repeater514such that a (peripheral) signal path is established between USB peripheral port522to the multiple input/output end of first signal repeater518. Control circuit506may also send another control signal to first signal repeater518such that only the USB signal to/from peripheral port522is repeated. As a result, there is a point-to-point signal path established between head unit502and USB host device510′, by-passing USB hub504. In this instance, USB host device510′ may take control of the active signal path established and thus exercise control over certain functions of head unit502, such as controlling information display an in-dash vehicle display unit.

In one particular embodiment, USB host device510may be a smartphone or tablet computer, more particularly an Apple® iPhone® or iPad® (hereinafter “Apple product”) that is CarPlay® enabled. In one alternative embodiment, USB host device510may be an Android® phone that is AndroidAuto® enabled. CarPlay® is an Apple® proprietary standard that enables a car head unit to be a display and also act as a controller for an iOS device or other USB peripheral devices. CarPlay® standard requires a USB system that operates in certain ways resembling a standard USB hub, but must also support one or multiple downstream USB ports that can “reverse direction” and become a USB host port, while the other downstream ports remain connected to the head unit as the USB host. Referring toFIG. 5B, when the Apple product is initially coupled to receptacle524a, it may behave as a USB peripheral, and connects to USB host port526of head unit502via USB hub504. When head unit502detects that an Apple product is connected, it may offer the user an option to enable CarPlay® application. The Apple product may continue to assume the role of a peripheral device if the user chooses not to activate the CarPlay® mode. In one alternative embodiment, the enabling of CarPlay® may be automatic and triggered by the coupling. In response to data exchanged between head unit502and the Apple product while it is in peripheral mode, CarPlay® mode may be initiated, and similar to the above description, head unit502may send USB command signals through USB host port526to control circuit506via USB hub504. In turn, control circuit506may send control signals to third and first signal repeaters514and518such that a point-to-point signal path is established between peripheral port522to the Apple product via third and first signal repeaters514and518, and receptacle524ain vehicle center console508. In one embodiment, the Apple product may act as a USB host and take control of the active signal path established and thus exercise control over certain functions of head unit502, such as controlling information display an in-dash vehicle display unit. Although USB peripheral port522may also be a USB OTG port, as there may not be any OTG support provided by USB hub504, non-standard approaches, such as by-passing USB hub504, may be required to allow the Apple product to switch from peripheral mode to host mode. In one embodiment, the Apple product may then become a USB host, and enumerate head unit502as a USB peripheral via USB peripheral port522. Concurrently, USB peripheral device512may also be coupled to receptacle524bsituated in vehicle center console508. In one embodiment, head unit502may send USB command signals to control circuit506, which may in turn send control signals to second signal repeater516to select or switch to USB D+/D− signal conductors from USB hub504, and not from third signal repeater514. As a result, a host signal path may be established between head unit502and USB peripheral device512via USB host port526, USB hub504, downstream port520c, and receptacle524bin vehicle center console508, resembling standard USB hub operation. In one embodiment, even when the CarPlay® mode is on via USB peripheral port522, USB peripheral device512and any other USB device(s) connected to another downstream USB port of the system (not shown inFIG. 5B) may continue uninterrupted USB peripheral operation through USB host port526.

Referring toFIG. 5C, USB peripheral device510is coupled to receptacle524aand USB host device512′ to receptacle524b. In one embodiment, USB host device512′ may be an Apple product. Operation of USB system580may be similar to USB system550inFIG. 5B. In one embodiment, head unit502may send USB command signals to control circuit506, which in turn may send control signals to first, second, and third signal repeaters518,516, and514. Host signal path may be established between head unit502and USB peripheral device510through USB host port526, USB hub504, downstream port520a, and first signal repeater518, in which head unit502acts as a USB host. Concurrently and individually, peripheral signal path may be established between USB peripheral/OTG port522of head unit502and the Apple product512′ after the CarPlay® mode is enabled through third signal repeater514, and second signal repeater516, in which the Apple product512′ acts as a USB host and head unit502a USB peripheral. In one embodiment, there may be two USB hosts, head unit502(to host signal path and USB device510) and the Apple product or USB host device512′ (to peripheral signal path and head unit502) in USB system580.

In one alternative embodiment (not shown), when head unit502detects both receptacles524aand524bare coupled to Apple products or USB host devices, head unit502may select one of the USB host devices for CarPlay® mode operation, or may offer the user an opportunity to select which USB host device is to be operated in CarPlay® mode.

Referring toFIGS. 5A to 5C, in various embodiments, each of receptacles524aand524b(or additional ports/receptacles) may be coupled to either a USB peripheral device, a USB host device, a USB OTG device, or any iPhone® in CarPlay® mode. Head unit502and control circuit506may generate appropriate control signals to signal repeaters to establish either a host signal path to USB host port526or a peripheral signal path to USB peripheral/OTG port522.

Referring toFIG. 5D, an alternative USB system600that is similar to USB system500inFIG. 5Ais illustrated. In one embodiment, control circuit602may not be a USB device and is not coupled to any downstream port of USB hub504. In one embodiment, head unit502generates and sends commands directly to control circuit602using a serial interface including but not limited to I2C or SPI, and control circuit602may in turn send control signals to first, second, third signal repeaters518,516, and514to effect signal path switching and control functions as described inFIGS. 5A to 5C.

Referring toFIG. 5E, another alternative USB system700is featured. In one embodiment, control signals are generated and sent directly from head unit502to first, second, third signal repeaters518,516, and514to effect signal path switching and control functions as described inFIGS. 5A to 5C.

Referring toFIG. 6, USB system800may be similar to USB system550inFIG. 5Band allows coupling to three USB devices and control circuit506concurrently. In one embodiment, an additional receptacle656, which may be a USB Type-C or other USB types receptacle, is mounted on vehicle center console508and an additional downstream port654in USB hub504. Besides, fourth signal repeater652may be coupled between USB device650and USB host port526via USB hub504or peripheral port522via third signal repeater514. In one embodiment, if USB device650is a peripheral device, head unit502may send USB commands to control circuit506, which may in turn configure fourth signal repeater652to select USB D+/D− signals from USB hub504in order to establish a host signal path between USB host port526and USB device650. In another embodiment, if USB device650is a USB host device, an OTG device, or an iPhone® in CarPlay® mode, head unit502may select or allow the user to select whether USB host device510′ or USB device650should be the host, and establish peripheral signal path accordingly. In alternative embodiments, one or more additional receptacle or port may be added to vehicle center console508with similar circuit modification as receptacle654, such that one or more USB device may be coupled to head unit502. In alternative embodiments, USB system800may adopt control circuit and control signal configuration embodiments as previously discussed inFIGS. 5D and 5E, and their description.

FIG. 7is a representative flowchart illustrating a method to implement signal switching and port swapping in a USB system, such as USB system500, in accordance with one embodiment of the subject matter. Referring toFIG. 7, a USB device, such as a head unit, may have a USB host port and a USB peripheral port, and the USB peripheral port may also be an OTG port. The USB host port may be coupled to an upstream port of a USB hub, and the USB peripheral port to a first switching unit, which may be a switch, a multiplexer or a signal repeater (“mux”), or a combination thereof, in step702. Subsequently, a second mux may be coupled to one downstream port of the USB hub and a third mux to another downstream port. The second and third muxes are further coupled to the first mux at its multiple input/output end, in step704. The second mux is further configured to be coupled to a first USB device and third mux to a second USB device, in step704. In one embodiment, a control block, similar to control circuit506inFIG. 5A, may be configured to transmit control signals to first, second, and third muxes to control their respective signal switching operation, in step706.

In one embodiment, the head unit may detect if the first USB device may act as a host, in step708. Control signals may be transmitted to the second mux, such that it may disconnect the USB hub to the first USB device, if the first USB device acts as a USB host. The second and/or first muxes may also be configured by the control signals to enable communication link from the peripheral port to the first USB device, in step712. If the first USB device is not USB host, the head unit may detect if the second USB device may act as a host, in step710. In one alternative embodiment, the head unit may detect if the second USB device may act as a host even when the first USB device is assuming the host role.

In one embodiment, control signals may be transmitted to the third mux, such that it may disconnect the USB hub to the second USB device if the first USB device acts as a USB host. The third and/or first muxes may also be configured by the control signals to enable connection link from the USB peripheral port to the second USB device, in step714. If the second USB device is not a USB host, communication links between the USB peripheral port of the head unit and both the second and third muxes may be disconnected, in step716. In one embodiment, the head unit may act as a USB host to both the first and second USB devices via the USB hub when both the first and second USB devices act as a USB peripheral, in step718.

Referring toFIG. 8A, USB system820that is similar to USB system500inFIG. 5A, and is USB Type-C compatible. In one embodiment, USB switches850ato850cmay perform similar functions to signal repeaters514,516, and518and accommodate top and bottom D+/D− USB signals from each of the Type-C ports. In one embodiment, the switching circuitry formed by USB switches850ato850cmay be a four input to 3 output (3×4) USB switch, such as a 3×4 USB 2.0 switch. The switching circuitry may route D+/D− lines of the top and bottom of each of the two USB Type-C ports (four inputs) to two downstream ports of the USB hub and the USB peripheral/OTG port of the head unit (three outputs). The operation of the switching circuitry may be similar to the embodiments disclosed inFIG. 7and its corresponding description.

FIG. 8Bis a schematic diagram illustrating USB switch850ain accordance with one embodiment of the subject matter. In one embodiment, USB switches850ato850cmay have similar structural features, and USB switch850ais illustrated herein as an example. In one embodiment, USB switch850amay be a two input to two input (2×2) USB switch, such as a 2×2 USB 2.0 switch. The two inputs may be D+ top/D− top and D+ bottom/D− bottom of one Type-C port/receptacle and the two outputs may be routed respectively to downstream port of USB hub and USB switch850c. In one embodiment, USB switch850amay have eight individual switches856, in which the operation of each switch856is configured by the control signals from the control circuitry. Each signal path to the USB peripheral/OTG port, for example D+ top, may have to pass through two stubs852,854and one switch856. In one embodiment, an active peripheral signal path between the USB peripheral/OTG port and the Type-C port may have to pass through four stubs852or854and two switches856(in USB switches850aand850cor850band850c). In one embodiment, USB signals may be degraded when switches, and to a lesser extent stubs are present in the signal path. Signal integrity may be preserved when fewer stubs and/or switches are present in the signal path.

Referring to9A, a USB type-C compatible USB system900is illustrated. In one embodiment, the shown system is similar to USB system820inFIG. 8A, wherein two Type-C ports/receptacles are present. In one embodiment, instead of using three 2×2 USB switches850ato850cas illustrated at least inFIGS. 5A and 8A, a single two input to three output (3×2) USB switching circuit902may be used to route appropriate signal path(s) to USB host and peripheral/OTG ports of the head unit, corresponding to the assumed role of connected USB device(s) (not shown inFIG. 9A). In one embodiment, D+/D− top and bottom signals of each of the Type-C ports are shorted at stub904to form the two inputs to USB switching circuit902. The USB switching circuit902may route D+/D− signals to one of the two downstream ports of the USB hub or the peripheral/OTG port of the head unit.

Referring toFIG. 9B, USB switching circuit902may include eight switches S1to S8, and the operations of switches S1to S8may be controlled by the control circuit. In each Type-C port, D+ top and D+ bottom lines are shorted at stub904and similarly for D− top and D− bottom lines to form one D+/D− input to USB switching circuit902. In one embodiment, the operation of USB switching circuit902is summarized as follow:

In one embodiment, when a USB peripheral device is coupled to Type-C Port 1 and an iPhone® to Type-C Port 2, D+ signal path from Type-C Port 1 may pass through switch S2and D− signal path through switch S6. In one embodiment, the point-to-point signal path from Type-C Port 2 to the USB peripheral/OTG port of the head unit may pass through only a single switch (S3for D+ and S7for D−) and three stubs904. The fewer switches and stubs along the signal path, compared to the 3×4 USB switch featured inFIG. 8Amay help reduce USB signal degradation and maintain signal integrity. In one embodiment, when both ports are coupled to a USB host or OTG device, such as an iPhone®, USB system900may allow users to select one of the two devices to be the USB host to the head unit, or may automatically revert to one of the first three configurations.

FIG. 10is a schematic diagram illustrating one application of the USB control and switching circuitry in an automobile in accordance with one embodiment of the subject matter. Referring toFIG. 10, automobile USB system1000includes center console or front seat power delivery (PD) charger1050, which may be a part of in-dash vehicle display, and rear seat PD charger1060. In one embodiment, center console PD charger1050may include control and switch circuitry1002athat may have similar features and functions as USB system500inFIG. 5A, 3×4 USB switch inFIG. 8A, or 3×2 switching circuit902inFIG. 9A. USB device1010amay include the control circuitry that is coupled to one downstream port of USB hub1006. Two other downstream ports of USB hub1006may be coupled to control and switch circuitry1002a, and one other downstream port to USB device (control circuitry) of rear seat PD charger1002b. Similar toFIG. 5A, peripheral/OTG port of head unit1050is coupled to control and switch circuitry1002aand USB host port to upstream port of USB hub1006. USB Type-C receptacles/ports1008aand1008bare configured to offer coupling to mobile USB devices (not shown). In addition, power delivery circuitry1004is also coupled to receptacles1008aand1008bto provide up to ˜20 V in fixed PDO mode and ˜21 V in PPS PDO mode charging to connected mobile USB devices, or other voltages such as those supported by USB-PD and/or USB-C specifications. In one alternative embodiments, there may be more than two receptacles in center console PD charger1050and the embodiment may be similar to the one featured inFIG. 6.

In one embodiment, control and switch circuitry1002amay perform signal path control and switching between head unit (either through USB host port or USB peripheral/OTG port) to connected mobile USB device(s). For example, when an iPhone® or another mobile phone (not shown) is coupled to receptacle1008a, it may behave initially as USB peripheral, and the signal path to is controlled by the head unit (not shown) via center console PD charger1050. When the head unit detects the iPhone®, it may offer the user the option to enable CarPlay® application. Once the iPhone® is CarPlay® enabled, control and switch circuitry1002amay establish a signal path/communication link between the USB peripheral/OTG port and the iPhone®, wherein the iPhone® is the USB host. In one alternative embodiment, the aforementioned port switching may happen automatically. In one embodiment, another mobile USB device (not shown) may be coupled to receptacle1008b, being USB peripheral to head unit via the USB host port. As discussed, the operation of the host signal path (USB host port to receptacle1008b) and peripheral signal path (USB peripheral/OTG port to the iPhone®) may exist concurrently, but operated individually. In one alternative embodiment, the iPhone® may be coupled to1008band the peripheral mobile USB device to receptacle1008ainstead.

In one embodiment, signal paths may be extended to rear seat PD charger1060through cascading. Control and switch circuitry1002bmay configure host signal paths to receptacle1008cand1008dfor coupling to peripheral mobile USB devices. In addition, power delivery circuitry1004may also provide up to ˜20 V in fixed PDO mode and ˜21 V in PPS PDO mode charging to those devices, or other voltages such as those supported by USB-PD and/or USB-C specifications. In one embodiment, OTG operation, iPhone® with CarPlay® operation, and other USB host operation may not be supported at receptacles1008cand1008d.

Embodiments of the subject matter include various operations described herein. These operations may be performed by hardware components, software, firmware, or a combination thereof.

Reference in the description to one embodiment or an embodiment means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the circuit or method. The appearances of the phrase one embodiment in various places in the specification do not necessarily all refer to the same embodiment.