Universal serial bus transceiver and associated methods

#1. Field

#The present invention is related to high speed signal transmission or communications, such as, for example, in a computing or computer system.

#2. Background Information

#The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portions of this specification. The invention, however, both as to organization, and method of operation, together with objects, features and advantages thereof, may best be understood by reference to the following detailed description, when read with the accompanying drawings in which:

#FIG. 1 is a schematic diagram illustrating portions of embodiments of, for example, two integrated circuits in accordance with the present invention, the integrated circuits being coupled by a cable; and

#FIG. 2 is a circuit diagram illustrating an embodiment of drivers that may be employed, for example, in one of the integrated circuits of FIG. 1.

#In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components and circuits have not been described in detail so as not to obscure the present invention.

#FIG. 1 is a schematic diagram that shows an embodiment 100 illustrating portions of embodiments of two integrated circuits in accordance with the present invention. Embodiment 100 includes integrated circuits 200 and 205, although the invention is not limited in scope in this respect. These integrated circuits may be included or incorporated into a variety of systems. For example, without limitation, a host computer and a peripheral in communication with the host computer. As illustrated in FIG. 1, these integrated circuits are coupled via a cable 110, which operates effectively as a transmission line in this context. In this particular embodiment, cable 110 comprises a twisted pair copper wire, although the invention is not limited in scope in this respect. In this particular embodiment, integrated circuit 205 includes an upstream transceiver and integrated circuit 200 includes a downstream transceiver. In this context, the upstream transceiver transmits communication signals to the downstream transceiver, such as from a host to a peripheral, as mentioned above, although the invention is not limited in scope in this respect. It is also noted that this definition of upstream and downstream is the reverse of the approach employed in the previously referenced standard USB specification.

#The transceivers illustrated are capable of communicating at low speed, that is 1.5 megabits per second, and at full speed, that is 12 megabits per second, for a standard USB transceiver, as well as at a higher speed. In this particular embodiment, the speed of the high speed signals is 125 megabits per second, although the invention is not limited in scope in this respect. Therefore, at low and full speed, the operation, in terms of signals, of this embodiment is substantially identical to standard USB compliant devices or transceivers. However, as shall be explained in more detail hereinafter, the transceiver is self-configurable in that it is capable of operating in a high speed mode, as well as at a low or a full speed mode. To accomplish this, in this particular embodiment, the transceiver configures itself between two architectures, a standard architecture and a high speed architecture. The added circuitry for the high speed architecture is transparent to the circuitry that operates in a manner that complies with the standard USB specification.