External power-saving usb mass storage device and power-saving method thereof
OwnerSzu-Ming CHEN, Cheng-Fang Liuinventors
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Abstract
An external power-saving USB mass storage device has a USB interface, a USB controller, an interface unit, a device controller and a memory unit. The USB controller has a sleep mode determination process embedded therein for predicting when a USB host plugged in by the USB mass storage device will not access the memory unit of the USB mass storage device for a prolonged time, and activates a sleep mode of the device controller through the interface unit so as to instruct the device controller and the memory unit to enter a power-down state for power-saving purpose.
Claims12
An external power-saving USB mass storage device, comprising:
- a USB interface adapted to be plugged into a USB host to receive a host command outputted from the USB host;
- a USB controller electrically connected with the USB interface and having a sleep mode determination process embedded therein;
- an interface unit electrically connected with the USB controller;
- a device controller having a sleep mode;
- and
- a memory unit electrically connected with the device controller for storing data;
- wherein the USB controller executes the sleep mode determination process to activate the sleep mode of the device controller through the interface unit and instruct the interface controller and the memory unit to enter a power-down state when predicting that the USB host will not send out any internal device instruction to access the memory unit for a prolonged time.
A power-saving method of an external power-saving USB mass storage device, wherein the external power-saving USB mass storage device has a USB interface, a USB controller, an interface unit, an interface controller and a memory unit;
- the power-saving method comprising steps of:
- receiving external host commands;
- predicting that data in the memory unit of the external power-saving USB mass storage device will not be read for a prolonged time, and determining a frequency of the external host commands containing internal device instruction;
- when the frequency of the received external host commands containing internal device instruction is low, activating the device controller of the external power-saving USB mass storage device to enter a sleep mode so as to instruct the device controller and the memory unit to enter a power down state;
- and
- when the frequency of the received external host commands containing internal device instruction is high, returning to the step of receiving the external host commands.
Dependencies are inferred from the claim text.