USB apparatus and USB hub apparatus

• US 6,363,491 B1
• Filed: 04/21/1999
• Issued: 03/26/2002
• Est. Priority Date: 04/23/1998
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Endo, Mitsunori
• Primary Examiner(s): AUVE, GLENN ALLEN
• Application Number:
  US09/295,867
• Time in Patent Office: 1,070 Days
• Field of Search: 713/300, 713/310, 713/320, 713/324, 713/340, 710/126, 710/129, 710/100, 710/107
• US Class Current: 713/310
• CPC Class Codes: G06F 13/4063 Device-to-bus coupling
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A USB apparatus or a USB hub apparatus having a USB port to be used for transmitting and receiving information to and from a host computer according to the USB protocol is provided with a power supplying means for supplying power to each internal section of the USB apparatus or the USB hub apparatus, a power supply voltage detecting means for detecting presence/absence of a power supply voltage to be supplied from the host computer to the USB port, and a supply power control means for controlling the power that is supplied by the power supplying means in accordance with a detection result of the power supply voltage detecting means. The power supply voltage detecting means detects a power supply voltage that is supplied from the host computer to the USB port and informs the supply power control means of the detection result. The supply power control means causes the power supplying means to stop supplying power to each internal section of the USB apparatus or the USB hub apparatus if no power is supplied from the host computer to the USB port (i.e., the power of the host computer is off), and controls the power supplying means to have it supply ordinary power to each internal section of the USB apparatus or the USB hub apparatus if power is supplied from the host computer to the USB apparatus or the USB hub apparatus.

Claims

1. A USB apparatus adapted for use with a host computer to transmit and receive information to and from said host computer according to a protocol that complies with a USB standard, comprising:

power supplying means for supplying power to each section of the USB apparatus;

power supply voltage detecting means for detecting presence/absence of a power supply voltage to be supplied from the host computer; and

supply power control means for controlling a level of the power supplied by the power supplying means of said USB apparatus in accordance with the detected power supply voltage from the host computer.

2. The USB apparatus according to claim 1, wherein the supply power control means causes the power supplying means to stop supplying power or supply low power if the power supply voltage detecting means has detected that the power supply voltage is not supplied from the host computer, and causes the power supplying means to supply high power if the power supply voltage detecting means has detected that the power supply voltage is supplied from the host computer.

3. A USB hub apparatus adapted to interconnect a host computer to one or more USB apparatuses and allow transmission and reception of information to be performed between the host computer and the USB apparatuses according to a protocol that complies with a USB standard, comprising:

power supplying means for supplying power to each section of the USB hub apparatus;

power supply voltage detecting means for detecting presence/absence of a power supply voltage to be supplied from the host computer; and

supply power control means for controlling a level of the power that is supplied by the power supplying means of said USB hub apparatus in accordance with the detected power supply voltage from the host computer.

4. The USB hub apparatus according to claim 3, wherein the supply power control means causes the power supplying means to stop supplying power or supply low power if the power supply voltage detecting means has detected that the power supply voltage is not supplied from the host computer, and causes the power supplying means to supply high power if the power supply voltage detecting means has detected that the power supply voltage is supplied from the host computer.