Reducing system power consumption due to USB host controllers
First Claim
1. A method of controlling a universal serial bus comprising:
- during a first frame, querying at least one device on the universal serial bus according to a periodic schedule;
thenduring N−
1 frames, not querying at least one device on the universal serial bus according to the periodic schedule, though the device is scheduled to be queried;
thenduring an Nth frame, querying at least one device on the universal serial bus according to the periodic schedule,wherein a value of N is progressively increased during a period of user inactivity.
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Accused Products
Abstract
Circuits, methods, and apparatus that reduce the power consumed by data transfers initiated by a USB host controller. Peripheral devices on a USB network are accessed with a reduced frequency in order to save power dissipated by a CPU and other circuits when reading data needed by the host controller. Instead of possibly accessing devices each frame, peripheral devices are accessed during some frames, and not accessed during others. A USB host controller may have two or more modes, such as a low power mode and a regular mode. In the low power mode, USB devices are accessed during fewer than all frames, in the regular mode, USB devices are possibly accessed each frame. Mode selection may depend on whether battery power is used.
13 Citations
37 Claims
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1. A method of controlling a universal serial bus comprising:
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during a first frame, querying at least one device on the universal serial bus according to a periodic schedule;
thenduring N−
1 frames, not querying at least one device on the universal serial bus according to the periodic schedule, though the device is scheduled to be queried;
thenduring an Nth frame, querying at least one device on the universal serial bus according to the periodic schedule, wherein a value of N is progressively increased during a period of user inactivity. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An integrated circuit comprising:
a first interface configured to; during a first frame, querying at least one device on the universal serial bus according to a periodic schedule;
thenduring N−
1 frames, not querying at least one device on the universal serial bus according to the periodic schedule, though the device is scheduled to be queried;
thenduring an Nth frame, querying at least one device on the universal serial bus according to the periodic schedule, wherein a value of N is progressively increased as a battery power level decreases. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method of controlling a universal serial bus comprising:
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during a first frame, traversing a periodic schedule;
thenduring N−
1 frames, not traversing the periodic schedule, though a device on the universal serial bus is scheduled to be accessed; and
thenduring an Nth frame, traversing the periodic schedule, wherein a value of N is progressively increased during a period of user inactivity.
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26. A method of controlling a universal serial bus comprising:
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during a first frame, querying at least one device on the universal serial bus according to a periodic schedule;
thenduring N−
1 frames, not querying at least one device on the universal serial bus according to the periodic schedule, though the device is scheduled to be queried;
thenduring an Nth frame, querying at least one device on the universal serial bus according to the periodic schedule; and commensurate with progressively increasing a value of N, rescheduling a device in the periodic schedule such that the device is accessed at a greater frequency. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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Specification