Apparatuses and methods for power saving in USB devices
First Claim
1. Universal Serial Bus (USB) device having reduced power consumption, the USB device comprising:
- a bus clock synchronization module configured to measure a bus clock period, wherein the bus clock period is associated with a communication bus connecting the USB device to a host device; and
a power control module configured to;
i) determine a first power save time period in which an application module of the USB device is to enter a first power save mode, wherein the application module is configured to perform application-specific functionality of the USB device;
ii) determine a second power save time period in which the communication bus is to enter a second power save mode, wherein determining the second power save time period is based on the first power save time period and the bus clock period;
iii) send a power save request to the host device, wherein the power save request corresponds to a request for the communication bus to enter the second power save mode for the second power save time period; and
iv) cause the USB device to enter a third power save mode of operation in response to a reply to the power save request, including causing the application module to enter the first power save mode for the first power save time period by communicating with the application module via an interface separate from the communication bus.
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Abstract
Circuits, architectures, systems, methods, algorithms and software for reducing power consumption of a universal serial bus (USB) device. Exemplary circuits and/or systems include a bus clock synchronization module configured to measure a bus clock period, and a power control module. The power control module is generally configured to determine an application power save period, determine a bus power save period based on the application power save period and the bus clock period, send a power save request, and enter a power saving mode of operation in response to a reply to the power save request. The present embodiments advantageously provide for reduced power consumption of a USB device and faster response during periodic states of activity and inactivity.
145 Citations
35 Claims
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1. Universal Serial Bus (USB) device having reduced power consumption, the USB device comprising:
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a bus clock synchronization module configured to measure a bus clock period, wherein the bus clock period is associated with a communication bus connecting the USB device to a host device; and a power control module configured to; i) determine a first power save time period in which an application module of the USB device is to enter a first power save mode, wherein the application module is configured to perform application-specific functionality of the USB device; ii) determine a second power save time period in which the communication bus is to enter a second power save mode, wherein determining the second power save time period is based on the first power save time period and the bus clock period; iii) send a power save request to the host device, wherein the power save request corresponds to a request for the communication bus to enter the second power save mode for the second power save time period; and iv) cause the USB device to enter a third power save mode of operation in response to a reply to the power save request, including causing the application module to enter the first power save mode for the first power save time period by communicating with the application module via an interface separate from the communication bus. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method for reducing power consumption by a Universal Serial Bus (USB) device, wherein the USB device includes a bus clock synchronization module configured to measure a bus clock period and a power control module configured to control the power consumption of the USB device, the method comprising:
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i) measuring a bus clock period, wherein said bus clock period is associated with a communication bus connecting the USB device to a host device; ii) determining, with the power control module, a first power save time period in which an application module is to enter a first power save mode, wherein the application module is configured to perform application-specific functionality of the USB device; iii) determining, with the power control module, a second power save time period in which the communication bus connecting the USB device to the host device is to enter a second power save mode, wherein determining the second power save time period is based on the first power save time period and the bus clock period; iv) sending a power save request to the host device via the communication bus, wherein the power save request corresponds to a request for the communication bus to enter the second power save mode for the second power save time period; and v) causing, with the power control module, the USB device to enter a third power save mode of operation in response to a reply to the power save request, including causing the application module to enter the first power save mode for the first power save time period by the power control module communicating with the application module via an interface separate from the communication bus. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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Specification