Patent Publication Number: US-2011066870-A1

Title: Peripheral capable of connecting with a host and power control method thereof

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a peripheral (e.g., a scanner) capable of connecting with a host (e.g., a computer) and a related power control method, and more particularly, to a device and a method for generating a power control signal by determining a status (a power-on status or a power-off status) of the host and for automatically switching on or switching off an input power of the peripheral according to the power control signal. 
     2. Description of the Prior Art 
     As far as certain peripherals of computers are concerned, such as a scanner, a printer, or a multi-function printer (MFP), their action modes of controlling power on/off statuses must be implemented by switching a power button in a manual manner. However, the peripheral operated with such action modes has the following disadvantages. When the peripheral is not in use, the peripheral is continuously in the device power-on status if the user does not have the habit of powering off the peripheral. Correspondingly, the lifetime and hours of use of internal electronic components (e.g., lamps or sensors) of the peripheral will be reduced, which results in unnecessary power consumption as well. 
     Hence, how to improve the life time of the internal electronic components of the peripheral, how to save power consumption, and how to increase more additional features to the peripheral have become one of the important topics in this field. 
     SUMMARY OF THE INVENTION 
     It is one of the objectives of the present invention to provide a peripheral capable of connecting with a host and a related power control method to solve the above-mentioned problems. 
     The present invention discloses a power control method for a peripheral, wherein the peripheral connects with a host via a transmission interface. The power control method includes the steps of: receiving signal data from the host via the transmission interface; determining a status of the host as a power-on status according to the signal data and a status of the peripheral as a device power-off status, and then generating a power control signal; and switching on an input power of the peripheral according to the power control signal, so as to make the peripheral enter a device power-on status from the device power-off status. 
     The present invention further discloses a power control method for a peripheral, wherein the peripheral connects with a host via a transmission interface. The power control method includes the steps of: receiving signal data from the host via the transmission interface; determining a status of the host as a power-off status according to the signal data and a status of the peripheral as a device power-on status, and then generating a power control signal; and switching off an input power of the peripheral according to the power control signal, so as to make the peripheral enter a device power-off status from the device power-on status. 
     The present invention further discloses a peripheral capable of connecting with a host. The peripheral includes a transmission interface, a detecting unit, and a switch unit. The transmission interface is used for receiving signal data from the host, wherein the power control circuit couples with the host via the transmission interface. The detecting unit is coupled to the transmission interface, for determining a status of the host according to values of the signal data and for generating a power control signal. The switch unit is coupled to the detecting unit, for selectively switching on or switching off an input power of the peripheral according to the power control signal. Herein when the detecting unit determines the status of the host as a power-on status, and the status of the peripheral as a device power-off status, the detecting unit outputs the power control signal to control the switch unit to switch on the input power, such that the peripheral enters a device power-on status from the device power-off status. Otherwise, when the detecting unit determines the status of the host as a power-off status, and the status of the peripheral as the device power-on status, the detecting unit outputs the power control signal to control the switch unit to switch off the input power, such that the peripheral enters the device power-off status from the device power-on status. 
     These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram showing a peripheral capable of connecting with a host according to a first embodiment of the present invention. 
         FIG. 2  is a diagram showing a peripheral capable of connecting with a host according to a second embodiment of the present invention. 
         FIG. 3A  and  FIG. 3B  are respectively a flowchart illustrating a power control method for a peripheral according to a first exemplary embodiment of the present invention. 
         FIG. 4A  and  FIG. 4B  are respectively a flowchart illustrating a power control method for a peripheral according to a second exemplary embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Please refer to  FIG. 1 . In this embodiment, the peripheral  100  couples with a host  170  via a transmission interface  150 . The peripheral  100  includes a power control circuit  110 , a voltage regulator  120 , a processing circuit  130 , and a power input port  140 . Herein the power input port  140  is coupled to a power supply  180 , for receiving an input power Vin (e.g., a DC voltage with 24V) outputted by the power supply  180  in order to supply needed power to the peripheral  100 . The power control circuit  100  is coupled to the power input port  140  and the voltage regulator  120 , and the power control circuit  100  has a transmission interface  150 , a detecting unit  160 , and a switch unit SW 1 . The transmission interface  150  is used for receiving signal data Sd from the host  170 , and the power control circuit  110  couples with the host  170  via the transmission interface  150 . In addition, the detecting unit  160  is coupled to the transmission interface  150 , for determining a status S 1  of the host  170  according to values (such as, “0” or “1”) of the signal data Sd and for generating a power control signal Spc to the switch unit SW 1 . The switch unit SW 1  is coupled to the detecting unit  160  and the power input port  140 , for selectively switching on or switching off the input power Vin inputted into the peripheral  100  according to the power control signal Spc. 
     For example, the signal data Sd received from the host  170  consists of a plurality of signal values. When at least one value of the signal data Sd is equal to 1, the detecting unit  160  determines that the status S 1  of the host  170  as a power-on status. At this time, if the peripheral  100  is in a device power-off status, the detecting unit  160  outputs a power control signal Spc to control the switch unit SW 1  to switch on the input power Vin, such that the peripheral  100  enters a device power-on status from the device power-off status. On the other hand, when all values of the signal data Sd are equal to 0, the detecting unit  160  determines that the status S 1  of the host  170  as a power-off status. At this time, if the peripheral  100  is under the device power-on status, the detecting unit  160  outputs the power control signal Spc to control the switch unit SW 1  to switch off the input power Vin, such that the peripheral  100  enters the device power-off status from the device power-on status. 
     Furthermore, the voltage regulator  120  is coupled to the switch unit SW 1  of the power control circuit  110 , for regulating the input power Vin passing through the switch unit SW 1 , and for distributing and transforming the input power Vin into required power of the processing circuit  130 , such that the processing circuit  130  is able to perform operations of the peripheral  100 . As an illustration, the voltage regulator  120  can distribute and transform a DC voltage with 24V into a DC voltage with 12V/5V/3.3V/2.5V. The processing unit  130  is coupled to the voltage regulator  120 , for receiving the distributed/transformed voltage in order to perform the operating procedures of the peripheral  100 . 
     The peripheral  100  may be an image processing device, such as: a scanner, a printer, or a multi-function printer (MFP). And thus the processing circuit  130  may be a scanner control circuit, used for performing a scanning procedure. 
     In one embodiment, the above-mentioned transmission interface  150  may be a USB interface and includes a D+ port and a D− port, and thus the detecting unit  160  can detect the signal data Sd via the D+ port and the D− port. As a result, when the detecting unit  160  detects that at least one value of the signal data Sd received by the D+ port and the D− port is equal to 1, the status S 1  of the host  170  is determined as the power-on status; and when the detecting unit  160  detects that both the values of the signal data Sd received by the D+ port and the D− port are equal to 0, the status S 1  of the host  170  is determined as the power-off status. 
     What&#39;s more, the above-mentioned detecting unit  160  can be implemented by a single USB Hub control circuit, or by the USB Hub control circuit coordinating with a USB device control circuit, but the present invention is not limited to this only. 
     Please refer to  FIG. 2 . The difference between  FIG. 2  and  FIG. 1  is that: a detecting unit  260  of the peripheral  200  is implemented by the USB Hub control circuit  270  coordinating with the USB device control circuit  280 . Herein the USB Hub control circuit  270  is coupled to the transmission interface  150 , for detecting the signal data Sd received by the D+ port and the D− port; while the USB device control circuit  280  is coupled to the USB Hub control circuit  270 , for detecting the signal data Sd via the USB Hub control circuit  270 . As an illustration, under a condition that the peripheral  200  is in the device power-off status, if at least one value of the signal data Sd is detected to be equal to 1, the USB device control circuit  280  outputs a link confirmed signal SL to the USB Hub control circuit  270  for confirming that the USB device control circuit  280  and a hard disk (not shown) of the host  170  are linked. At this time, when the USB Hub control circuit  270  detects that at least one value of the signal data Sd is equal to 1 and the link confirmed signal SL has been received, it determines that the status S 1  of the host  170  as the power-on status and then outputs the power control signal Spc to control the switch unit SW 1  to switch on the input power Vin. On the other hand, under a condition that the peripheral  200  is in the device power-on status, if both the signal values of the signal data Sd are detected to be equal to 0, the USB Hub control circuit  270  determines that the status S 1  of the host  170  as the power-off status and then outputs the power control signal Spc to control the switch unit SW 1  to switch off the input power Vin. 
     Please refer to  FIG. 3A  and  FIG. 3B  by collocating with the corresponding elements shown in  FIG. 1  in the meantime. Herein  FIG. 3A  is a flowchart representing how to switch on the input power Vin of the peripheral  100  under a condition that the peripheral  100  is in the device power-off status; while  FIG. 3B  is a flowchart representing how to switch off the input power Vin of the peripheral  100  under a condition that the peripheral  100  is in the device power-on status. 
     As shown in  FIG. 3A , the method includes the following steps: 
     Step  302 : Start. 
     Step  304 : Receive the signal data from the host via the transmission interface. 
     Step  306 : Determine the status of the host according to the signal data. When determining that the status of the host is the power-on status, go to the step  308 ; otherwise, when determining that the status of the host is the power-off status, go to the step  312 . 
     Step  308 : Output the power control signal to control the switch unit to switch on the input power of the peripheral. 
     Step  310 : The peripheral enters the device power-on status from the device power-off status. 
     Step  312 : End. 
     As shown in  FIG. 3B , the method includes the following steps: 
     Step  352 : Start. 
     Step  354 : Receive the signal data from the host via the transmission interface. 
     Step  356 : Determine the status of the host according to the signal data. When determining that the status of the host is the power-off status, go to the step  358 ; otherwise, when determining that the status of the host is the power-on status, go to the step  362 . 
     Step  358 : Output the power control signal to control the switch unit to switch off the input power of the peripheral. 
     Step  360 : The peripheral enters the device power-off status from the device power-on status. 
     Step  362 : End. 
     Please refer to  FIG. 4A  and  FIG. 4B  by collocating with the corresponding elements shown in  FIG. 2  in the meantime. Herein  FIG. 4A  is a flowchart representing how to switch on the input power Vin of the peripheral  200  under a condition that the peripheral  200  is in the device power-off status; while  FIG. 4B  is a flowchart representing how to switch off the input power Vin of the peripheral  200  under a condition that the peripheral  200  is in the device power-on status. 
     As shown in  FIG. 4A , the method includes the following steps: 
     Step  402 : Start. 
     Step  404 : Receive the signal data from the host via the transmission interface. 
     Step  406 : The USB Hub control circuit detects the signal data received from the host via the transmission interface, so as to determine the status of the host. When determining that the status of the host is the power-on status, go to the step  408 ; otherwise, when determining that the status of the host is the power-off status, go to the step  418 . 
     Step  408 : The USB device control circuit detects the signal data via the USB Hub control circuit, so as to determine the status of the host. When determining that the status of the host is the power-on status, go to the step  410 ; otherwise, when determining that the status of the host is the power-off status, go to the step  418 . 
     Step  410 : The USB device control circuit outputs a link confirmed signal to the USB Hub control circuit. 
     Step  412 : The USB Hub control circuit outputs the power control signal to the switch unit. 
     Step  414 : The switch unit switches on the input power of the peripheral. 
     Step  416 : The peripheral enters the device power-on status from the device power-off status. 
     Step  418 : End. 
     As shown in  4 B, the method includes the following steps: 
     Step  452 : Start. 
     Step  454 : Receive the signal data from the host via the transmission interface. 
     Step  456 : The USB Hub control circuit detects the signal data received from the host via the transmission interface, so as to determine the status of the host. When determining that the status of the host is the power-off status, go to the step  458 ; otherwise, when determining that the status of the host is the power-on status, go to the step  464 . 
     Step  458 : The USB Hub control circuit outputs the power control signal to the switch unit. 
     Step  460 : The switch unit switches off the input power of the peripheral. 
     Step  462 : The peripheral enters the device power-off status from the device power-on status. 
     Step  464 : End. 
     Please note that, the steps of the above-mentioned flowcharts are merely practicable embodiments of the present invention, and in no way should be considered to be limitations of the scope of the present invention. These methods can include other intermediate steps or several steps can be merged into a single step without departing from the spirit of the present invention. 
     In summary, the present invention provides a peripheral capable of connecting with a host and a related power control method. By adding the power control circuit  110  or  210  into the peripheral, it is able to generate the power control signal according to determining the status of the host as the power-on status or the power-off status and to automatically switch on/switch off the input power of the peripheral according to the power control signal. That is to say, the peripheral can be automatically controlled to enter the device power-on status/device power-off status with the power-on status/power-off status of the host, in order to replace the traditional manual manner of switching the status of the peripheral, which can bring more convenience to the user. Herein under a condition that the peripheral is in the device power-off status, the power control circuit switches on the input power of the peripheral when the status of the host is the power-on status, in order to perform the action of automatically powering on the peripheral. Under another condition that the peripheral is in the device power-on status, the power control circuit switches off the input power of the peripheral when the status of the host is the power-off status, in order to perform the action of automatically powering off the peripheral. Therefore, when the host is power off or enters the sleeping mode, the host will release the link between the electronic components of the peripheral (such as the detecting unit  160 , the USB Hub control circuit  270 , and the USB device control circuit  280 ) so as to extend the lifetime and hours of use of the electronic components of the peripheral, which can further achieve a goal of saving power consumption. 
     Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention.