USB port with smart power management
First Claim
1. A method comprising:
- (a) detecting an inrush current condition of a USB port when a central processing unit (CPU) of a first electronic device is not being powered, wherein the first electronic device includes the USB port and the CPU, and wherein the inrush current condition is due to a second electronic device being plugged into the USB port.
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Accused Products
Abstract
A method involves detecting an inrush current that flows out of a USB port of a first electronic device when a central processing unit (CPU) of the first electronic device is not being powered. The inrush current is detected by a novel inrush current detect circuit when a second electronic device is connected to the USB port. In one example, the first electronic device is a laptop computer having a battery and a USB DC-to-DC converter. The inrush current detect circuit enables the USB DC-to-DC converter such that the USB DC-to-DC converter receives power from the battery and supplies a regulated voltage to the second electronic device through the USB port while the CPU remains unpowered (not drawing power from the battery).
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Citations
26 Claims
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1. A method comprising:
(a) detecting an inrush current condition of a USB port when a central processing unit (CPU) of a first electronic device is not being powered, wherein the first electronic device includes the USB port and the CPU, and wherein the inrush current condition is due to a second electronic device being plugged into the USB port. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A device comprising:
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a central processor unit (CPU); a USB port; and means for detecting an inrush current condition when the CPU is not being powered, wherein the inrush current condition is due to a second electronic device being plugged into the USB port. - View Dependent Claims (11)
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12. A method comprising:
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(a) detecting an inrush current flowing out of a USB port when a central processing unit (CPU) of a battery-powered device is not being powered, wherein the battery-powered device includes the USB port, the CPU, a battery, and a DC-to-DC converter; and (b) in response to said detecting, enabling the DC-to-DC converter so that the DC-to-DC converter receives power from the battery and supplies a regulated voltage onto a terminal of the USB port, wherein the regulated voltage is supplied onto the terminal when the CPU is not being powered by the battery. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A device comprising:
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a central processing unit (CPU) that is unpowered; a battery; a USB port; a DC-to-DC converter; and an inrush current detect circuit, wherein upon a detection of an inrush current flowing out of the USB port, the inrush current detect circuit enables the DC-to-DC converter such that the DC-to-DC converter receives power from the battery and supplies a regulated DC voltage onto a terminal of the USB port, and wherein the regulated DC voltage is supplied onto the terminal while the CPU remains unpowered. - View Dependent Claims (19, 20, 21, 22, 23)
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24. An integrated circuit comprising:
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a first terminal that receives a first supply voltage; a second terminal that receives a second supply voltage; a DC-to-DC converter that is operable in an enabled mode and a disabled mode, wherein the DC-to-DC converter is powered by the first supply voltage and generates a third voltage in the enabled mode; a selection circuit that is controllable by the second supply voltage and that couples a selectable one of either the second supply voltage or the third voltage onto a third terminal; and an inrush current detect circuit powered by the first supply voltage, wherein the inrush current detect circuit detects an inrush current flowing out of the third terminal and enables the DC-to-DC converter to operate in the enabled mode, wherein a host device includes a central processing unit (CPU) and a USB port, wherein the third terminal is on the USB port, and wherein the CPU is not being powered when an electronic device is being plugged into the USB port of the host device. - View Dependent Claims (25, 26)
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Specification