USB host determination of whether a USB device provides power via a USB coupling
First Claim
1. A system configured to act as a USB host, comprising:
- a battery;
a USB charging port for coupling to USB devices;
device logic,wherein the device logic is configured to;
determine that a USB device is coupled to the USB charging port, thereby providing a USB coupling between the USB host and the USB device;
determine whether the USB device is providing power via the USB coupling, wherein the USB host detects a change in current direction on a Vbus line of the USB coupling; and
based on detecting a change in current direction on the Vbus line, the USB host compares the voltage provided by the Vbus line and a voltage available from the USB host to detect a back drive indication;
if determined that the USB device is not providing power, the device logic is further configured to;
determine a power level for providing power to the USB device wherein the power level is determined based on one or more handshake procedures; and
provide power at the determined power level to the USB device via the USB coupling;
if determined that the USB device is providing power, the device logic is further configured to;
determine whether the power provided by the USB device can be used to charge the battery of the USB host; and
based on determining that the power provided by the USB device can be used to charge the battery of the USB host, charge the battery using power provided by the USB device via the USB coupling.
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Accused Products
Abstract
System and method for a USB host to determine whether or not a USB device provides power via a USB coupling between the USB host and the USB device. At a first time, it may be determined that the USB device is coupled to the USB host via a USB coupling and does not provide power. Power may be provided to the USB device via the USB coupling. At a second time it may be determined that the USB device does provide power via the USB coupling. Power may no longer be provided to the USB device via the USB coupling after it is determined that the USB device does provide power via the USB coupling. A battery of the USB host may be charged using power provided by the USB device via the USB coupling based on determining that the USB device does provide power via the USB coupling.
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Citations
16 Claims
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1. A system configured to act as a USB host, comprising:
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a battery; a USB charging port for coupling to USB devices; device logic, wherein the device logic is configured to; determine that a USB device is coupled to the USB charging port, thereby providing a USB coupling between the USB host and the USB device; determine whether the USB device is providing power via the USB coupling, wherein the USB host detects a change in current direction on a Vbus line of the USB coupling; and based on detecting a change in current direction on the Vbus line, the USB host compares the voltage provided by the Vbus line and a voltage available from the USB host to detect a back drive indication; if determined that the USB device is not providing power, the device logic is further configured to; determine a power level for providing power to the USB device wherein the power level is determined based on one or more handshake procedures; and provide power at the determined power level to the USB device via the USB coupling; if determined that the USB device is providing power, the device logic is further configured to; determine whether the power provided by the USB device can be used to charge the battery of the USB host; and based on determining that the power provided by the USB device can be used to charge the battery of the USB host, charge the battery using power provided by the USB device via the USB coupling. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for a USB host to determine whether or not a USB device provides power via a USB coupling between the USB host and the USB device, the method comprising:
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determining that the USB device is coupled to the USB host via a USB coupling; determining whether the USB device is providing power via the USB coupling, wherein the USB host detects a change in current direction on a Vbus line of the USB coupling, and based on detecting a change in current direction on the Vbus line, the USB host compares the voltage provided by the Vbus line and a voltage available from the USB host to detect a back drive indication; if determined that the USB device is not providing power, the method further comprising; determining a power level for providing power to the USB device wherein the power level is determined based on one or more handshake procedures; and
providing power at the determined power level to the USB device via the USB coupling;if determined that the USB device is providing power, the method further comprising;
determining whether the power provided by the USB device can be used to charge a battery of the USB host; andbased on determining that the power provided by the USB device can be used to charge the battery of the USB host, charging the battery of the USB host using power provided by the USB device via the USB coupling. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A system configured to act as a USB host, comprising:
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a battery; a USB charging port for coupling to USB devices; device logic, wherein the device logic is configured to; determine that a USB device is coupled to the USB charging port, thereby providing a first USB coupling between the USB host and the USB device; determine whether the USB device is providing power via the USB coupling wherein the USB host detects a change in current direction on a Vbus line of the USB coupling and the USB host compares the voltage provided by the Vbus line and a voltage available by the USB host to detect a back drive indication; if determined that the USB device is not providing power, the device logic is further configured to; determine a power level for providing power to the USB device wherein the power level is determined based on one or more handshake procedures; and provide power at the determined power level to the USB device via the first USB coupling; if determined that the USB device is providing power, the device logic is further configured to; determine whether the power provided by the USB device can be used to charge the battery of the USB host; and based on determining that the power provided by the USB device can be used to charge the battery of the USB host, charge the battery using power provided by the USB device via the USB coupling. - View Dependent Claims (16)
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Specification