Electrical computers and digital processing systems: support – Computer power control – Power conservation
Reexamination Certificate
2000-03-31
2001-05-08
Etienne, Ario (Department: 2155)
Electrical computers and digital processing systems: support
Computer power control
Power conservation
C713S310000, C713S322000, C713S323000, C713S324000
Reexamination Certificate
active
06230277
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to reduced power consumption in home appliances and information devices having communication functions, and more particularly, to a peripheral device consuming less power with a part of its functions being operated intermittently, and a control method thereof.
2. Description of the Background Art
Infrared communication is often used as means of connecting control devices such as remote controllers and keyboards with controlled devices, in order to remotely control the home appliances and information devices, as well as to alleviate inconvenience of a wired connection.
Normally, the remote control devices such as remote controllers not only control the functions being provided while the controlled devices are in operation, including channel change, volume control, and command input, but also control switching on/off of the controlled devices.
If the controlled device is a home appliance, an infrared receive unit is normally incorporated therein in advance. However, information devices are often designed for general purposes.
IrDA Control is a system standardized by the Infrared Data Association (IrDA), a U.S.-based infrared communication standardizing organization, for remote control of home appliances and information devices, or for two way information exchanges. The IrDA Control system is controlled by the Universal Serial Bus (USB) system for versatility and ease of design when connected to or incorporated in an information device.
FIG. 1
illustrates connection between a PC incorporating a USB host controller and an external IrDA Control peripheral device (hereinafter, referred to as an “IrDA Control Dangle”).
The USB host controller-contained PC
300
and the IrDA Control Dangle
302
are connected by a USB cable
301
. The user can control PC
300
by an IrDA Control keyboard
303
or an IrDA Control mouse
304
which is connected to IrDA Control Dangle
302
by infrared rays.
Recently, a controlled information device, such as a personal computer, is designed to enter a sleep mode or a power OFF mode automatically or by the order of a user if it is not used for a long time period, to save power consumption.
However, even when the personal computer is in the sleep mode, the IrDA Control Dangle incorporated in, or connected via a USB cable to, the information device is designed to constantly function. Thus it is possible to recover the PC from its sleep mode by manipulating the IrDA Control keyboard, mouse or the like.
There are two possible ways to supply power to the IrDA Control Dangle. One is to directly supply power from the outside via an AC adapter or the like. The other is to supply power via the USB cable.
According to the USB Physical Layer Specification (Revision 1.1), a current up to 500 mA is supplied to a peripheral device through the USB cable when the USB host controller is in operation. Supplying the power through the USB is preferable because it is more convenient as the user does not need to ensure external power supply every time.
When the USB is in a sleep mode, however, the supply current of the USB is reduced to an average of 2.5 mA per second to save power consumption (the maximum standby current is permitted up to 100 mA if within 1 &mgr;s). Therefore, there arises a problem that an IrDA Control Dangle consuming the current of greater than 2.5 mA cannot be made to function when the PC is in the sleep mode.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a peripheral device consuming less power supplied from a host device, and a control method thereof.
Another object of the present invention is to provide a peripheral device capable of fulfilling the USB physical layer specification even when the host device is in a sleep mode, and a control method thereof.
A still further object of the present invention is to provide a peripheral device improved in operability of a user, and a control method thereof.
According to an aspect of the present invention, a peripheral device operating with power supplied from a host device includes: a receive unit receiving an external signal; and a controller causing at least a part of functions of the peripheral device to operate intermittently when the host device is in a sleep mode, and, upon reception of the external signal via the receive unit, forcing the host device to shift to an active mode according to the signal received.
At least a part of the functions of the peripheral device is forced by the controller to operate intermittently while the host device is in the sleep mode. Thus, it is possible to reduce consumption of the power supplied from the host device. Further, by adjusting the time ratio between the active mode and the sleep mode during the intermittent operation, it is possible to fulfill the USB physical layer specification. Moreover, by setting the period of the active mode during the intermittent operation to be as long as possible, the detection of the external signal becomes easier, whereby the operability of the user is improved.
According to another aspect of the present invention, a control method of the peripheral device operating with the power supplied from the host device includes the steps of: causing at least a part of functions of the peripheral device to operate intermittently when the host device is in a sleep mode; receiving an external signal; and forcing the host device to shift to an active mode according to the external signal received.
When the host device is in the sleep mode, at least a part of the functions of the peripheral device operates intermittently. This reduces consumption of the power supplied from the host device. Further, by adjusting the time ratio between the active mode and the sleep mode during the intermittent operation, it is possible to fulfill the USB physical layer specification. Moreover, by setting the period of the active mode during the intermittent operation to be as long as possible, the detection of the external signal becomes easier, and thus, the operability of the user is improved.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 5404544 (1995-04-01), Crayford
patent: 5706110 (1998-01-01), Nykanen
patent: 5987338 (1999-11-01), Gibbons et al.
patent: 5987339 (1999-11-01), Asano
patent: 6038612 (2000-03-01), Liow
Nakaoka Hiroyuki
Otani Yoshihiro
Uno Hiroshi
Etienne Ario
Sharp Kabushiki Kaisha
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