Patent Application
20050240709
One significant development in the evolution of personal computers is the introduction of the universal serial bus (USB). USB is described in “Universal Serial Bus Specification,” versions 1.1 and 2.0, Compaq Computer Corporation, et al. The USB specification was developed to provide an external expansion bus which facilitates the attachment and removal of peripheral devices to/from a computer. Since its introduction, USB has enjoyed widespread acceptance in the marketplace.
Prior to USB, a personal computer required a separate interface, with specialized electrical, mechanical and software interfaces, to connect to each individual peripheral device. Thus, before the advent of USB, a personal computer required separate interfaces for its keyboard, mouse, monitor, printer, microphone, joy stick, scanner, etc. With USB, USB-capable peripherals can be connected directly to a USB bus of the personal computer without the need for any specialized mechanical, electrical or software interfaces.
Generally, on a USB system, there is one USB host which is typically a personal computer built around a USB-capable motherboard and equipped with USB software. The host acts as the master of the bus, acknowledging attachment and removal of peripherals, initiating enumeration processes and all subsequent USB transactions on the bus, collecting status and activity statistics, and controlling the electrical interface between the host and USB peripherals. USB peripherals act as slaves on the bus and are of two types: “hubs” and “functions.” A “hub” typically consists of a hub controller and a repeater, and usually converts a single upstream attachment port into multiple downstream attachment ports. “Functions” are peripherals such as a keyboard, mouse, camera and the like. A “function” can be self-powered or may derive its power from the USB bus; likewise, a “hub” can be self-powered or bus-powered, to provide power to downstream devices (which may be hubs or functions) attached to its ports.
In one aspect of the invention, an expansion card for adding to a computer system a Universal Serial Bus (USB) port is disclosed. The expansion card comprises: an Accelerated Graphics Port (AGP) card connector configured to enable the expansion card to be inserted into an AGP expansion slot of the computer system; and at least one USB port each adapted to mate with a USB-compatible peripheral device, wherein a USB data signal recieved at the AGP connector is routed to the USB port.
In another aspect of the invention, an expansion card is disclosed. The expansion card comprises: a plurality of connectors through which USB data, USB power and power signals are received, wherein each connector is matable with a corresponding connector of the computer system; a plurality of Universal Serial Bus (USB) ports adapted to mate with a USB-compatible device; and circuitry for routing the USB data, USB power and power signals from the plurality of connectors to the USB ports. One of the plurality of connectors is an Accelerated Graphics Port (AGP) card connector configured to enable the expansion card to be inserted into an AGP expansion slot of the computer system.
In a further aspect of the invention, an expansion card is disclosed. The expansion card comprises a plurality of connectors for receiving USB data, USB power and additional power signals, comprising an Accelerated Graphics Port (AGP) card connector configured to enable the expansion card to be inserted into an AGP expansion slot of the computer system; at least one Universal Serial Bus (USB)-Plus-Power port each adapted to mate with a USB-compatible device; and means for routing the USB data, USB power and additional power signals received at the plurality of connectors to the USB-Plus-Power port.
Each USB-Plus-Power port 104 includes a receptacle that provides a USB data signal and a +5VDC USB power signal. As is well-known in the art, each USB data signal comprises the parallel transmission of two signals: a USB data+signal and a USB data-signal. Each USB-Plus-Power port 104 also includes a separate receptacle that provides additional power to USB devices that require more power than the 5 volts available through a standard USB connector. In this exemplary embodiment, the additional power provided by the power contacts of two USB-Plus-Power ports 104A, 104B is a 12 VDC power signal, while the additional power provided by the power contacts of USB-Plus-Power port 104C is a 24 VDC power signal. It should be appreciated that in alternative embodiments, expansion card 102 can be configured with any quantity and combination of USB ports and/or USB-Plus-Power ports, and that the implemented USB-Plus-Power ports, if any, may provide the same or different voltages.
In accordance with some embodiments of the present invention, expansion card 102 comprises an AGP connector 106A configured to enable the expansion card to be inserted into an AGP expansion slot 106B of computer system 100. As shown in
In the particular embodiment illustrated in
In some embodiments of the present invention, USB connector 108A is a standard USB connector matable with a corresponding standard USB connector 108B of computer system 100. In such embodiments, USB connector 108A has two sets of USB contacts. One set of USB contacts carries USB1 data signal 138 while the other set of contacts carries USB2 data signal 134. Two USB power signals 136 and 140 are also provided to expansion card 102 through USB connectors 108A/108B. USB data and power signals 134, 136, 138 and 140 are generated by, for example, a USB controller 112 in computer system 100. In addition, USB connector 108A comprises a contact for providing a mating status signal 132 to computer system 100, as described below.
USB1 data signal 138 is routed to USB-Plus-Power port 104A, while USB2 data signal 134 is routed to USB-Plus-Power port 104B. The two USB power signals 136, 140 are routed to all USB-Plus-Power ports 104A-104C. USB power signal 136 is permanently connected to a 5 VDC source in computer system 100 and is also provided to mating detection circuit 120, as described below. Also, USB power signal 140 is present in certain power states of computer system 100 to provide power to USB-Plus-Power ports 104 so that computer system 100 can be powered/revived via a USB port during certain power states. One embodiment of USB connector 108A is described in detail below.
Associated with each USB port 104A-104C is an optional signal conditioning circuit 118A-118C, respectively. As described in detail below, signal conditioning circuits 118 filter, adjust or otherwise manipulate the signals to be presented at their respective USB-Plus-Power ports 104 to ensure compliance with the appropriate specifications and to maintain signal integrity. One exemplary embodiment of a signal conditioning circuit 118A is described in detail below.
Expansion card 102 has a voltage doubling circuit 122 that converts 12 VDC power 124 received at power connector 110A to 24 VDC power signal 142 for USB-Plus-Power port 104C. As shown in
In accordance with certain embodiments of the present invention, expansion card 102 comprises a mating detection circuit 120. Mating detection circuit 120 may determine whether any combination of cable connector(s) and/or card connector(s) is mated with their counterparts in computer system 100. In
Mating detection circuit 120 can generate any number of mating status signals each representing the mating status of any desired combination of one or more cable and/or card connectors. The mating status signals is/are provided to other component(s) of computer system 100 for processing to determine the presence and/or integrity of the electrical connections between expansion card 102 and other components of computer system 100. In the embodiment illustrated in
USB power signals 136 and 140 are provided at contacts 2 and 1, respectively of USB connector 108A. Both USB power signals 136 and 140 are routed to all USB-Plus-Power ports 104, as described above and as shown in
As shown in
Of the remaining contacts in USB connector 108A, contact 8 is grounded while contacts 9 and 10 are unused.
As one of ordinary skill in the art would find apparent, power connector 110A can have the same or different quantity of contacts, and may have the same or additional contact assignments that that illustrated in
Voltage doubling circuit 122 comprises an inductor 506 connected in series with the anode of a diode 508. The input of inductor 506 is connected to the 12 VDC power signal 124 received from power connector 110A. Inductor 506 stores energy which is delivered to diode 508. The manner in which the energy is delivered to diode 508 is controlled by the state of a FET 504. The drain of FET 504 is connected to the anode of diode 508, and the source of the FET is connected to ground. The gate of FET 506 is connected to a switched output (pin 2) of a switching regulator 502. Switching regulator 502 generates a FET drive signal at its switched output to open and close FET 504 and cyclically alternate the polarity of inductor 506. Cyclically connecting and disconnecting the output of inductor 506 to ground causes a +24 VDC signal to be presented at the cathode of diode 508.
In the embodiment shown in
At the input of voltage doubling circuit 122 is a choke 510. Choke 510 is an inductor that filters the switching noise generated by the switching operations performed by voltage doubling circuit 122, preventing such noise from returning to computer system 100 through the power connection 110A/110B. Filtering capacitors 512 may be included in voltage doubling circuit 122 to provide bulk and/or high frequency filtering of +12 VDC signal 124. The 12 VDC power signal 124 is then presented to the drive collector (pin 8) and switch collector (pin 1) of switching regulator 502, respectively. Switching regulator 502 may have appropriate resistors 522, 524 at the drive collector (pin 8) and switch collector (pin 1) to attain proper drive and source control of the implemented switching regulator 502.
Switching regulator 502 is current limiting; that is, it will cease operating when the current of 12 VDC power signal 124 exceeds a predetermined threshold value. Series connected between choke 510 and switching regulator 502 is a current sensing resistor 514. Voltage input (pin 6) and peek current sense input (pin 7) of switching regulator 502 are connected across current sense resistor 514 to monitor the current levels of the signals presented at pins 8 and 1.
Voltage doubling circuit 122 includes a feedback circuit 516 connecting the cathode of diode 508 to a feedback input (pin 5) of switching regulator 502. The voltage presented at the feedback input (pin 5) is determined by a voltage divider circuit comprising resistors 520A and 520B. Switching regulator 502 utilizes such feedback to determine the period of the FET drive signal generated at switch emitter (pin 2) to insure the voltage at the anode of diode 508 is 24.7 VDC and, therefore, the output of voltage doubling circuit 122 is held at 24 VDC.
Decoupling capacitors 518 may be connected between the output conductor of voltage doubling circuit 122 and a ground potential to provide signal decoupling and bulk storage should there be a transient draw at USB-Plus-Power port 104C.
In addition, USB-Plus-Power port 104A provides additional power to USB devices that require more power than the +5 volts available at a standard USB connector. This additional power is supplied through a set of contacts contained within a power receptacle 604 of USB-Plus-Power port 104A. As noted, power receptacle 604 is preferably compliant with Application-Specific Connector USB Specification Addendum, which is incorporated by reference above.
In this exemplary embodiment of USB-Plus-Power port 104A, the power provided at power receptacle 604 is 12 VDC. In one alternative embodiment, the power provided at power receptacle 604 may be 24 VDC, similar to USB-Plus-Power port 104C. As shown in
With continued reference to
USB1 data+signal 302A and USB1 data—signal 302B are provided to contacts 2 and 3, respectively, of USB receptacle 602, as noted above. An optional electromagnetic interference (EMI) suppression circuit 616 may be included in signal conditioning circuit 118A to filter electromagnetic interference signals that may be carried on the signal lines that also carry USB1 data signals 302. In addition capacitors 610 and 612 may be included to adjust the rise and fall times of the USB1 data signals 302 as necessary to insure signal integrity at USB receptacle 602.
Signal conditioning circuit 118A also receives USB power signal 140 from USB connector 108A. USB power signal 140 is passed through an inductor 606 and a load circuit 608 to place a small load on the circuit to ensure power supply 116 remains stable. A capacitor 618 may be connected between the conductor carrying USB power signal 140 and ground to filter high frequency noise carried on the signal conductor that also carries USB power signal 140.
As noted, power receptacle 604 provides a power signal to a device connected to USB-Plus-Power port 104A. As shown in
A capacitor 612 may be connected between the conductor carrying +12 VDC power signal 124 and ground. Capacitor 612 provides bulk decoupling of devices connected to USB-Plus-Power port 104A to insure power is continually provided to such a connected device under conditions of a heavy transient power draw. A second, smaller capacitor 614 may also be connected between the conductor carrying +12 VDC power signal 124 and ground to provide signal filtering of +12 VDC power signal 124 prior to the power signal being presented at contacts 6 and 7 of power receptacle 604.
Expansion card 102 comprises, as noted, a mating detection circuit 120 that detects whether one or more selected connectors 106A, 108A, 110A of the expansion card are mated with the corresponding connectors. That is, mating detection circuit 120 determines whether USB connector 106A is mated with USB connector 106B; power connector 110A is mated with power connector 110B; and/or AGB connector 106A is mated with AGB expansion slot 106B. One or more signals provided by, derived from or controlled by signals received at connectors 106A, 108A and/or 110A is/are monitored by mating detection circuit 120 to make such determination(s). Mating detection circuit 120 generates at least one signal each representing whether a selected combination of one or more connectors 106A/106B, 108A/108B and/or 110A/110B is/are mated.
As shown in
Mating detection circuit 120 provides mating status signal 132 to other components of computer system 100 for monitoring. In the embodiment illustrated in
A logical representation of the operation performed by the above embodiment of mating detection circuit 120 is shown in
Mating detection logic 900 also receives another signal directly or indirectly from, or controlled by, AGB connector 106A. The presence of this signal indicates that the card connector(s) are mated, as indicated by signal 910. Mating detection logic 900 implements another AND function 906, generating a mating detection status signal 912 when both, the cable connector(s) status signal 908 and the card connector(s) status signal 910 are present.
It should be appreciated by those of ordinary skill in the art that in an alterative embodiment cable connector(s) mated signal 908 and/or card connector(s) mated signal 910 may be generated as output signals similar to mating status signal 912. In such an embodiment all three signals may control individual GPIO bits which are readable by BIOS 114. Such an embodiment may facilitate the diagnosis of an inoperable USB port AGB expansion card 102.
As noted, embodiments of mating detection circuit 120 can monitor any signal provided by, derived from or controlled by connectors 106, 108 and/or 110. For example, the +5Vdc signal 914 monitored in the embodiment illustrated in
It should be appreciated that expansion card 102 enables USB ports and/or USB-Plus-Power ports to be added to a computer system without consuming other valuable resources of the computer system, such as a PCI (Peripheral Component Interconnect) slot, and without having to redesign or add internal circuit boards to provide, for example, voltage doubling circuit 122.
It should also be appreciated that implementation of a mating detection circuit such as that described above provides a simple way for a computer system to automatically detect the presence of an expansion card during the manufacturing process. For example, during manufacturing assembly, the proper and complete installation of expansion card 102 would otherwise be determined by manually connecting a high-powered USB peripheral device to one of the card's USB Plus-Power ports 104. The detection circuit eliminates the labor and delay associated with such an approach.
Although embodiments of the present invention have been fully described in conjunction with the preferred embodiment thereof with reference to the accompanying drawings, it is to be understood that various changes and modifications may be apparent to those skilled in the art. For example, in the above embodiments, expansion card 102 provides three USB Plus-Power ports 104. In alternative embodiments, expansion card 102 provides a fewer or greater quantity of USB Plus-Power ports 104. As another example, USB ports 104 are USB Plus-Power ports, as described above. The operating voltage transmitted through the universal serial bus is limited to 5 volts. This limits the power that can be consumed by peripherals connected on a universal serial bus. The USB Plus-Power ports 104 implemented in the above embodiment of expansion card 102 provides additional power to USB devices that require power not available through the standard USB ports. It should be appreciated, however, that not all USB ports provided on an AGB expansion card 102 may provide such additional power, and that universal USB ports can be implemented in addition to or in place of the noted USB Plus-Power ports 104. As a further example, detection circuit 120 is implemented on expansion card 102 in the above-described embodiments. In alternative embodiments, mating detection circuit 120 may be implemented in any other component of compute system 100. In a further example, the embodiment of the AGP expansion card 102 includes a voltage doubling circuit 122 to provide +24 VDC to one USB Plus-Power port 104C. The voltage doubling circuit 122 will not easily fit on the motherboard of computer system 100 so implementing the circuit on AGB expansion card 102 makes available the +24 VDC to USB devices while not requiring significant redesign of the motherboard or the design of a dedicated daughter card. However, it should be appreciated that a USB Plus-Power port 104 that provides +24 VDC may not be implemented in alternative embodiments. Similarly, all USB-Plus-Power port(s) 104 implemented on alternative embodiments of expansion card 102 can provide +24 VDC or no ports may provide +12 VDC. While not implemented on the expansion cards described above, a USB hub can be implemented in expansion card 102 to expand the number of USB ports. Such an embodiment may be desirable, for example, if USB data signals 134, 138 are not available. In such an embodiment, USB3 data signals present on AGP connector 106A may be attached to a USB hub on expansion card 102. The additional power signal may also be obtained from AGP connector 106 if the current draw is not excessive for such a card connector. Alternatively, the additional as well as the USB power can be obtained from power connector 110A, if available. The USB hub would expand the number of USB ports available on the expansion card. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims.
