JP2010165271A - Electric power control apparatus and electric power control method - Google Patents

Abstract

A power control apparatus and a power saving control method capable of flexibly reducing power consumption regardless of whether or not a response to a suspend signal transmitted from a host computer is possible.
A power control apparatus includes a host computer, a USB hub connected to the host computer, and a device connected to the USB bus after the USB hub. When the computer 2 shifts to the suspend mode, the computer 2 is provided with switch means (the switch control unit 20 and the on / off switch 30) that receives a predetermined command and turns off the power supplied to the device 50.
[Selection] Figure 1

Description

  The present invention relates to a power control apparatus and a power control method including a device that can be connected to a host computer and connected by a USB hub.

  In various information devices such as personal computers, peripheral devices compatible with USB (Universal Serial Bus) have become widespread due to the high degree of freedom in scalability. Since USB is a star-type network structure bus, a USB device system (power control device) in which a plurality of USB standard devices are connected using a connection function called a USB hub is configured, and the USB device system is configured by a host computer. The control form of controlling is common.

  FIG. 6 is a block diagram showing a schematic configuration of a conventional USB device system. The USB device system 101 connected to the host computer 200 via the USB bus 100 is mainly composed of a USB bus 102 including a USB controller, various devices 103 under it, a power supply unit 104, and the like. The USB device system 101 (power control device) includes, for example, a media drive that writes data to a printer, a DVD, or the like as the device 103, and these are configured as one device.

  By the way, in the USB specification such as OHCI (Open Host Controller Interface), a suspend mode for reducing power consumption is defined in the USB controller that manages the device 103. In the suspend mode, the operation of most function units other than the part for detecting the insertion / removal of the device with respect to the USB connector is stopped. Since the return from the suspend mode is performed by a software reset that does not involve a hardware reset, the internal state such as register information in the USB controller can maintain the value immediately before the software reset.

  On the other hand, various power management modes are also set on the host computer 200 side, and in the suspend mode similar to the above, the main memory storing the system data necessary for restarting the operating system, the user program, etc. Most of the functional units other than the control unit are stopped. The stored system data includes the operating state of the operating system and application program, and user data created by the application program. The return from the suspend mode is performed by a resume reset signal. The resume reset signal is supplied only to the device that is powered off in the suspend mode, and the device is initialized. The host computer 200 also has a system reset signal that is generated when the power is turned on and for initializing all devices in the system.

  In the conventional USB device system, the device 103 at the rear stage of the USB hub 102 shifts to the power saving mode by an individually mounted timer, and then shifts to the suspend mode as a whole system by the USB suspend signal from the host computer 200. There was a general power saving mode.

JP-A-11-194847 (pages 4-9, FIG. 1)

  However, in the conventional USB device system, when the USB controller shifts to the suspend mode and then the entire system enters the suspend mode of the host computer, the device cannot recover from the reset signal sent from the host computer. There was a problem that existed.

  In addition, in order to avoid that the device cannot return from the suspend mode, the application program on the host computer side that controls the device locks in advance so as not to enter the suspend mode, that is, there is a device that cannot enter the suspend mode. There was also.

  For this reason, a reset control circuit for selectively supplying a system reset signal and a resume reset signal is provided in front of the reset signal input terminal of the USB controller, even when the USB controller is turned off during the suspend mode of the host computer. There has also been proposed a computer system configured to be able to resume reset (see, for example, Patent Document 1).

  However, in the system disclosed in Patent Document 1, since only a uniform state (power on or off) can be selected for all USB devices under the USB controller, depending on the status of the operating system and application programs, the device There is a problem in that it is not possible to flexibly reduce power consumption by individually controlling on / off.

  An object of the present invention is to solve the above problems, and by providing a physical switching means for switching on / off of power supply for each USB device, whether or not a response to a suspend signal transmitted from a host computer is possible. It is an object of the present invention to provide a device power control apparatus and a power control method capable of flexibly reducing power consumption.

In order to achieve the above-described object, a power control apparatus according to the present invention is connectable to a host computer, a USB hub connected to the host computer, and a device connected to the subsequent stage of the USB hub via a USB bus And a switch means for turning off the power supplied to the device in response to a predetermined command transmitted when the host computer shifts to the suspend mode. .
According to the above configuration, even a device that cannot be shifted to the suspend mode by the suspend signal can cut off the power supply to the device. Therefore, power consumption of the apparatus including the device can be reduced.
Preferably, the predetermined command is a USB suspend signal, and the switch means receives the USB suspend signal and turns off the power supplied to the device.
According to the above configuration, the power supply to a device that can be shifted to the suspend mode by the suspend signal can be cut off. Therefore, power consumption of the apparatus including the device can be reduced.
Further preferably, the predetermined command is a power-off command generated by the host computer, and the switch means receives the power-off command and turns off the power supplied to the device.
According to the above configuration, the on / off switch can be controlled using the application program of the host computer to cut off the power supply to the device. Therefore, power consumption of the apparatus including the device can be reduced.
Preferably, the power supply is selected by selecting from a plurality of devices.
According to the above configuration, the power supply can be individually cut off for the devices in the apparatus. Therefore, control for reducing the power consumption of the apparatus can be flexibly performed.
Preferably, the switch means receives a return command transmitted when the host computer returns from the suspend mode to the normal mode, and turns on the power supplied to the device.
According to the above configuration, when the host computer returns to the normal mode, the device that has been turned off returns to the state just before the transition to the suspend mode. Therefore, it is possible to appropriately control the power without causing any trouble in the operation of the devices in the apparatus.

In order to achieve the above-described object, a power control method of the present invention is connectable to a host computer, a USB hub connected to the host computer, and a device connected by a USB bus downstream of the USB hub. , A power control method of a power control apparatus configured with switch means for controlling power supply to the device, wherein the USB hub receives a predetermined command transmitted when the host computer shifts to a suspend mode And the step of switching off the power supplied to the device in response to the predetermined command.
According to the above power control method, even if a device cannot be shifted to the suspend mode by the suspend signal, the power supply to the device can be cut off. Therefore, power consumption of the apparatus including the device can be reduced.
Further, the command includes information for selecting a specific device from the plurality of devices and turning off the power to be supplied. The power supply can be turned off individually for the devices in the apparatus.

It is a block diagram showing a schematic structure of a power control device concerning an embodiment of the present invention. 1 is a schematic diagram showing a schematic structure of a media processing apparatus that is a specific example of a USB device system 1; FIG. 1 is a block diagram illustrating a schematic configuration of a media processing apparatus that is a specific example of a USB device system 1; FIG. It is a flowchart which shows the power saving control operation procedure (operation | movement which turns off the power supply of a USB device) of the power control apparatus which concerns on embodiment of this invention. The flowchart which shows the power-saving control operation procedure (operation | movement which turns on the power supply of a USB device) of the power control apparatus which concerns on embodiment of this invention. The block diagram which shows schematic structure of the conventional USB device system.

  Hereinafter, embodiments of a power control device and a power control method according to the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a schematic configuration of a power control apparatus according to an embodiment of the present invention. The power control apparatus is connectable to the host computer 2 and is a USB device system 1 (power control apparatus) connected to the host computer 2. Specifically, the USB device system 1 mainly includes a USB hub 10, a switch control unit 20, an on / off switch 30, a power supply unit 40, a USB device 50, and the like.

  The host computer 2 controls the operation of the USB device system 1 connected via the USB bus 3. The USB hub 10 includes a USB controller. The switch control unit 20 is configured by a microcomputer equipped with a USB bus, for example, and is connected to the USB hub 10. The switch control unit 20 performs switching control of an on / off switch 30 described later based on a switch control command 4 transmitted from the host computer 2 and received via the USB hub 10.

The on / off switch 30 is composed of, for example, an FET (Field Effect Transistor) installed in the middle of a power supply line 41 that supplies power from the power supply unit 40 to each device 50, and an output signal from the switch control unit 20. The line 25 can be connected to the gate terminal of the FET to switch the power supply to the device 50 and cut off individually.
The switch control unit 20 and the on / off switch 30 described above both function as switch means. Power saving control is realized by controlling the switch control unit 20 using an application program executed on the host computer 2 and switching the on / off switch 30 to turn off the power of each device as appropriate.

For example, as a specific example having a plurality of devices of the USB device system 1 described above, a media processing apparatus is an example. FIG. 2 is a schematic diagram illustrating a schematic structure of the media processing device, and FIG. 3 is a block diagram illustrating a schematic configuration of the media processing device.
As shown in FIG. 2, in the media processing apparatus 1A, the label printer 51, the media drive 52, and the media transport mechanism 53 are covered by a housing (not shown), and data writing and label printing are performed on the media. The label printer 51 performs label printing on one side of a medium such as a CD or a DVD. Media drive 52 also writes data to the other side of the media. The media transport mechanism 53 drives these transport arms to connect these devices (label printer 51, media drive 52) and media stackers (blank media stacker, processed media stacker, discharged media stacker, etc.) to stack media. Transport media between. As shown in FIG. 3, the media processing device 1A includes a label printer 51, a media drive 52, and a media printer 52 via a USB hub 10 that is a branch device for connecting a plurality of devices to the USB port of the host computer 2. Three devices of the media transport mechanism 53 are connected. In FIG. 3, the switch controller 20, the on / off switch 30, the power supply unit 40, and the like are omitted.

Next, the power saving control operation of the power control apparatus according to the embodiment of the present invention will be described.
FIG. 4 is a flowchart showing a power saving control operation procedure (operation for turning off the power of the USB device) of the power control apparatus according to the embodiment of the present invention.
First, the application program of the host computer 2 transmits a switch control command to the USB device system 1 immediately before shifting to the suspend mode (step S10). The host computer 2 shifts to the suspend mode after transmitting the switch control command (step S11).

  The USB device system 1 receives the switch control command at the command receiving unit 21 of the switch control unit 20 (step S12). The command analysis unit 22 analyzes the control content related to the received command (received switch control command) (step S13), and the command conversion unit 23 generates a corresponding switch control signal (step S14). As a result, the on / off switch 30 of the corresponding device 50 is turned off (step S15), the power supply is cut off, and the operation is stopped (step S16). Note that the device 50 may be in the suspend mode by the USB controller before receiving the switch control command. The reception command includes information for selecting a specific device from among a plurality of devices and turning off the power to be supplied, whereby the power to be supplied to the specific device can be turned off.

FIG. 5 is a flowchart showing a power saving control operation procedure (operation for turning on the power of the USB device) of the power control apparatus according to the embodiment of the present invention.
First, when the host computer 2 returns from the suspend mode (step S20), the application program transmits a switch control command to the USB device system 1 (step S21).

  The USB device system 1 receives the switch control command at the command receiving unit 21 of the switch control unit 20 (step S22). The command analysis unit 22 analyzes the control content related to the received command (step S23), and the command conversion unit 23 generates a corresponding switch control signal (step S24). As a result, the on / off switch 30 of the corresponding device is turned on (step S25), and the power supply is started to be in an operating state (step S26). At this time, a device that is turned off can be selected and turned on.

Through the power saving control operation described above, the power supply to each device 50 (in the specific examples of FIGS. 2 and 3, the label printer 51, the media drive 52, and the media transport mechanism 53) is individually cut off as appropriate. Therefore, unnecessary power consumption can be suppressed and power consumption can be reduced.
In the above embodiment, the switch control command 4 does not necessarily have to be transmitted via the USB bus 3. That is, if there is other means for connecting the host computer 2 and the switch control unit 20, the switch control command may be transmitted using the means.

  As described above, according to the power control device and the power saving control method according to the embodiment of the present invention, the physical switching means for switching on / off of the power supply is provided for each device, so that the host computer can Power consumption can be reduced regardless of whether the device responds to the suspend signal of the device or not. In particular, since the power supply to the device is directly cut off, the amount of reduction can be greatly improved compared to a standby state in which some power is consumed.

  DESCRIPTION OF SYMBOLS 1 ... USB device system, 2 ... Host computer, 3 ... USB bus, 4 ... Switch control command, 10 ... USB hub, 20 ... Switch control part, 21 ... Command reception part, 22 ... Command analysis part, 23 ... Command conversion part 30 ... ON / OFF switch, 40 ... power supply unit, 41 ... power supply line, 50 ... device

Claims (7)

A power control device that can be connected to a host computer and has a USB hub connected to the host computer and a device connected by a USB bus downstream of the USB hub,
A power control apparatus comprising switch means for turning off power supplied to the device in response to a predetermined command transmitted when the host computer shifts to a suspend mode.   2. The power control apparatus according to claim 1, wherein the predetermined command is a USB suspend signal, and the switch unit receives the USB suspend signal and turns off the power supplied to the device.   The said predetermined command is a power-off command generated by the host computer, and the switch means receives the power-off command and turns off the power supplied to the device. Power control device.   4. The power control apparatus according to claim 1, wherein the switch unit selects a plurality of the devices and turns off a power supply to be supplied. 5.   5. The switch unit according to claim 1, wherein the switch unit receives a return command transmitted when the host computer returns from the suspend mode to the normal mode, and turns on the power supplied to the device. The power control device according to one item. A USB hub that can be connected to a host computer, and is composed of a USB hub connected to the host computer, a device connected by a USB bus downstream of the USB hub, and switch means for controlling power supply to the device A power control method for a power control device, comprising:
The USB hub receiving a predetermined command to be transmitted when the host computer enters the suspend mode;
The switch means receives the predetermined command and turns off the power supplied to the device;
A power control method comprising:   The power control method according to claim 6, wherein the predetermined command includes information for selecting a specific device from the plurality of devices and turning off the power to be supplied. .

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