Abstract:
An apparatus and method for waking up a main processor (MP) in a low power or ultra-low power device preferably includes the MP, and a sub-processor (SP) that utilizes less power than the MP to monitor ambient conditions than the MP, and may be internalized in the MP. The MP and SP can remain in a sleep mode while an interrupt sensor monitors for changes in the ambient environment. A sensor is preferably an interrupt-type sensor, as opposed to polling-type sensors conventionally used to detect ambient changes. The MP and SP may remain in sleep mode, as a low-power or an ultra-low power interrupt sensor operates with the SP being in sleep mode, and awakens the SP via an interrupt indicating a detected change. The SP then wakes the MP after comparing data from the interrupt sensor with values in storage or with another sensor.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a low-power wake-up method for an electronic device having a sensor. More particularly, the present invention relates to ways to reduce battery power utilized by portable devices and facilitate a return of the electronic device to operation from a sleep mode. 
     2. Description of the Related Art 
     In order to save power, which is of particular importance to battery powered devices, conventionally a “sleep mode” has been utilized, typically when the electronic device is an idle state for a predetermined amount of time. 
     Battery usage in portable electronic devices, including but not limited to cell phones, smart phones, tablets, personal digital assistants (PDA&#39;s), portable music players, etc., are just a few of the many types of devices where battery usage is critical, and there continues to be a need to provide more functionality and at the same time reduce power battery usage. 
     Conventional devices, wherein after a period of time of non-usage, may dim the brightness of the display, or the display goes blank to conserve energy. 
     For example, with regard to computers, sleep mode is defined as an energy-saving standby condition of a computer which can be reactivated by external stimulus, such as touching the keyboard. For example, when a notebook computer goes into sleep mode, the display screen and disk drive are normally shut down. Once awakened (i.e. sent a specific signal), the computer returns to its former operating status. 
     Moreover, in the case of portable electronic devices, sleep mode operates, for example, in devices that are in no way limited to smartphones, tablets, music players, Personal Digital Assistant (PDAs), just to name a few possibilities. 
     In fact, many smartphones now default to a sleep mode when not used, unless actively performing certain tasks. When there are no active user interactions such as screen touches, every component, including the central processor, can stays off unless an app instructs the operating system to keep the device fully powered on. 
     Moreover, a number of background operations need to be performed while the phone is idle. In one such example, a mailer may need to automatically update email by checking with a remote server. To prevent the phone from going to sleep during such operations, smartphone manufacturers often make application programming interfaces, or APIs, available to app developers. The developers insert the APIs into apps to instruct the phone to stay awake long enough to perform necessary operations. 
     In a typical smartphone, an Application Processor (AP) is asleep when the device is asleep. In order to wake up the device, conventional systems require the user to press a power button or an unlock button. 
     Sleep mode saves battery power, particularly when compared with leaving a device in fully operation state while idle, and advantageously permits the user to avoid having to reset programming codes or wait for an electronic device to reboot. In wireless electronic devices, such as portable mobile terminals, tablets, etc., which often seek out networks and have to provide passwords to obtain access upon being rebooted or reset, the use of sleep mode is preferable to a rather cumbersome and slow process or rebooting. 
     However, to return to an operational mode from a sleep mode (wake mode) requires an action to be undertaken by the user. For example, a power button or an unlock icon must be pressed, which is slow and sometimes awkward, especially when trying to quickly perform an action on the electronic device. Even in the case of a virtual keypad, an unlock icon must be touched or spread in order to restore the electronic device to an operational mode, meaning that the user is inconvenienced by contacting a button of the device, or sliding their finger along a screen. 
     Some conventional attempts to solve some of the shortcomings include providing a luminance sensor or a camera. However, in such cases the application processor (AP) cannot go into sleep mode and must always be in an operating mode to process sensed data from the sensor or camera. This type of monitoring requires a high amount of power consumption, as it is impossible to control the sensor by the AP directly when the AP is asleep. 
     Recently, the use of a lower power processor for processing only the sensing data has been configured into the devices. However, the low power processor processes data from the sensor using a polling type, and must be maintained in a wake-up state, using significant amounts of power. 
     With regard to conventional attempts to address the above-discussed issues, U.S. Pat. Appln. Pub. No. 20100313050 discloses that a sensor processor system selects a power profile to be applied to the application processor system based on the sensed data, and instructs the power management controller to apply the selected power profile to the application processor system. There are two processors used for low power sensing that wakes up the AP when the sensed data meets the condition. 
     However, a significant drawback to U.S. Pat. Appln. Pub. No. 2010/0313050 is that the sensor processor always operates to monitor ambient environment using a polling type sensor without a sleep mode. The sensor processor applies the power profile to the application processor system (S/W type). 
     In another conventional attempt to improve the art, in U.S. Pat. Appln. Pub. No. 2009/0259865, the electronic device includes a circuit configured to operate when the main processor is in the sleep mode. The circuit comprises at least one low power processor and a sensor. However, the low power processor in the conventional system always operates without being in sleep mode in order to be able to monitor ambient environment via a polling-type sensor. 
     Accordingly, there is a need in the art for a system and method that permits additional components to be in sleep mode and yet, provides ambient monitoring of the device, and can permit a switch back to an operating mode from sleep mode quickly without pressing buttons or touching the display screen. 
     SUMMARY OF THE INVENTION 
     The summary of the invention is not to be used as a basis to interpret a scope of the appended claims, as the claimed invention is far broader than the description in this summary. 
     An apparatus and method for waking up a main processor in an ultra-low power device preferably includes a main processor, and a sub-processor that utilizes less power than the main processor, and may be internalized in the main processor. According to an exemplary aspect of the presently claimed invention, at least one sensor is preferably an interrupt-type sensor (as opposed to, for example, a polling-type sensor). One of the many advantages of the presently claimed invention is that both the main processor and the sub-processor can remain in sleep mode, as a low-power or an ultra-low power sensor can operate with the sub-processor being in sleep mode and only awaken after receiving an interrupt signal from the interrupt sensor that a change has been detected. 
     In addition, the presently claimed invention also permits a return from sleep mode to operating mode by a mere wave of the hand, which is unknown heretofore. Also, shaking the unit, or moving a stylus pen arranged along an exterior of the device are all examples of the many ways the device can be awakened from sleep mode. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other exemplary aspect of the invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  shows a block diagram of an exemplary depiction of an apparatus according to an exemplary aspect of the invention; 
         FIG. 2  shows a flowchart illustrating an exemplary operation for gesture sensing according to an exemplary aspect of the invention; 
         FIG. 3A  shows a flowchart illustrating an exemplary operation of a feedback voice input based on device&#39;s motion according to an exemplary aspect of the invention; 
         FIG. 3B  is an exemplary overview of an AP Processor to Hub Processor Protocol according to an illustrative aspect of the present invention; 
         FIG. 3C  is an example of a message frame that can be used with an AP to Hub Protocol according to an illustrative aspect of the present invention; 
         FIG. 3D  is an example of an AP processor communicating with a second processor hub, according to an AP to Hub protocol that can be used with the present invention; 
         FIG. 4  shows a flowchart illustrating exemplary operation of a signature unlock based on stylus movement according to an exemplary aspect of the invention; 
         FIG. 5  shows a current profiling example according to an exemplary aspect of the invention; and 
         FIG. 6  shows an example of a wireless device incorporating the present invention. 
     
    
    
     It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. Moreover, the drawings are not necessarily drawn to scale and, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and at least one of a low power processor and an ultra-low power sensor to monitor at least one of the signals, commands, inputs, and changes in the environment. The circuit wakes up the main processor responsive to one of the low power processor and the ultra-low power interrupt sensor. 
     DETAILED DESCRIPTION 
     The present invention has been described with respect to particular exemplary embodiments and with reference to certain drawings, but the invention is not limited thereto, but rather, is set forth only by the appended claims. The drawings described are only schematic and are non-limiting. In the drawings, for illustrative purposes, the size of some of the elements may be exaggerated and not drawn to a particular scale. Where the term “comprising” is used in the present description and claims, it does not exclude other elements or steps. Where an indefinite or definite article is used when referring to a singular noun, e.g. “a” “an” or “the”, this includes a plural of that noun unless something otherwise is specifically stated. Hence, the term “comprising” should not be interpreted as being restricted to the items listed thereafter; it does not exclude other elements or steps, and so the scope of the expression “a device comprising items A and B” should not be limited to devices consisting only of components A and B. This expression signifies that, with respect to the present invention, the only relevant components of the device are A and B. 
     Furthermore, the terms “first”, “second”, “third” and the like, if used in the description and in the claims, are provided for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances (unless clearly disclosed otherwise) and that the exemplary embodiments of the invention described herein and may be operated in other sequences and/or arrangements than are described or illustrated herein. 
     DEFINITIONS 
     To aide in an understanding of the present invention, an artisan should understand and appreciate that the terms “main processor” and sub-processor” are terminologies used for understanding of the invention, but other terminologies can be interchangeably used in place of main processor and sub-processor having the same meaning. 
     For example, to aid the artisan, the term “main processor”, can be any one of an “application processor”, “AP”, “first processor”, and “processor  1 ” as used herein all refer to the same processor  110  that is shown in  FIG. 1 . A high power processor can be referred to as a main processor, or an application processor. The main processor typically is considered high power relative to the low power sub-processor or sensing processor. 
     In addition, the term “sub-processor”, can be any one of a “sensing processor”, “MCU”, “second processor”, “processor  2 ”, “Sensor Hub (Processor)”, MCU (Micro Controller Unit”, I refer to the same processor  120  that is shown in  FIG. 1 . An ultra-low power processor can be referred to as any of the above. 
     An artisan understands and appreciates that the term “ultra-low power” typically refers to a processor operating at power consumption values using less than approximately 1 mA, and often in the μA range. “Ultra-low power levels” refers to power consumption at levels using less than approximately 1 mA. 
     In addition, the artisan also understands and appreciates that the term “low power” typically refers to a processor (or sub-processor) operating in the 1-10 mA range. The apparatus may comprise a wireless communication device, such as a mobile communication terminal, a cellphone, smart phone, tablet, Personal Digital Assistant (PDA), notebook, netbook, etc. just to name a few possible non-limiting examples of devices. 
       FIG. 1  shows a block diagram of an exemplary depiction of an apparatus  100  according to an exemplary aspect of the invention that includes a main processor (HP for high power) that is typically an application processor, a sub-processor  120  (LP for low power) that receives information from sensors such as interrupt uLP sensor  130  (ultra-low power) and a polling  140  (that may or may not be ultra-low power). 
     The sub-processor  120  operates at a low power or ultra-low power, and according to the present invention, the sub-processor can remain in a sleep mode along with the main processor  110  because of the use of an interrupt sensor  130 . As discussed herein above, the conventional apparatus uses only a polling sensor that requires either the main processor or the sub-processing to remain fully operational to be able to have the device change from sleep mode to operational mode. 
     The interrupt sensor  130  operates at ultra-low power levels and sends an interrupt signal to the sub-processor  120  when a predetermined condition is sensed, which can be, for example, waiving one&#39;s hand in front of the display, shaking the device, or moving a piece of the device, such as shifting a position of a stylus  475  ( FIG. 4 ) or part of the cover. According to the present invention, the interrupt sensor  130  is operable while the sub-processor  120  is in sleep mode. However, the polling sensor  140  requires the sub-processor to be in awake mode or operating mode (not in sleep mode). 
       FIG. 2  shows a flowchart illustrating an exemplary operation for gesture sensing according to an exemplary aspect of the invention. 
     At step  200 , the main processor  110  and sub-processor  120  are in sleep mode. At steps  210  and  220 , an interrupt sensor  130  (including but not limited to an infrared (IR) sensor) detects gesture sensoring within a proximity distance of the electronic device, typically a display or touchscreen. The proximity distance can be, for example, 10-15 cm, but the invention does not require a specific distance, so long as the sensor can recognize the wave of the user&#39;s hand. 
     At step  230 , the sub-processor  120  is awakened by the interrupt signal sent from the interrupt sensor  130 . Alternatively, at step  240  an accelerometer may detect the device being shaken or waived, and also cause the sub-processor  120  to be awakened. 
     At step  250 , the sub-processor determines whether or not the sensed data from the interrupt sensor  130  is valid by comparing the value with a table in storage. 
     In addition, a polling sensor  130  can be optionally included so that when the mobile device is placed in a case or bag, the interrupt sensor does not unintentionally operate. Accordingly, the sub-processor wakes up due to the interrupt from the interrupt sensor, and the main processor wakes up when 1) sensing data of the interrupt sensor is within valid range or 2) when sensing data of the polling sensor is within the valid range, with 1) or 2) being determined by the sub-processor at step  250 . 
     After determining by the sub-processor  120  that the data is valid, for example, by being in a valid range, or has reached a predetermined threshold, the sub-processor  120  at step  260  then wakes the main processor  110 , which in turn at step  270  provides feedback to the user, in the form of, for example, unlocking the screen, prompting the user, making the display operable, showing a home screen, etc. According to an exemplary aspect of the present invention, the predetermined threshold could be a particular value which if the output is greater than or equal to, is determined by the sub-processor as satisfying the wake up condition(s). In addition, there can be a range of range of values received from the sensor that are predetermined as satisfying a wakeup condition, that being provided only for purposes of illustration and not for limiting the appended claims, such as, for example a microvolt uv (or microamp ua) range. Any other such range (e.g. ma) that is within the capability of the sub-processor to distinguish between values received from the sensor so as ascertain a valid range or predetermined threshold are within the spirit and scope of the claimed invention. 
       FIG. 3A  shows a flowchart illustrating an exemplary operation of a feedback voice input based on device&#39;s motion according to an exemplary aspect of the invention. This particular exemplary embodiment starts at step  300  with the main processor and sub-processor being asleep. A motion detector detects motion at step  310 , by sensing the predetermined condition (in this example is the device being shaken or waved) at step  320 , and the interrupt signal is sent to the sub-processor  120  to wake up the sensing processor at step  330 . Then the sub-processor at step  340  determines whether or not the sensed data is valid, by comparing with values in storage to determine if the data is within a valid range or has reached a predetermined threshold, for example. Upon determining that the sensed data from the interrupt sensor is valid, then at step  350  the sub-processor  120  wakes up the main processor  110 . The main processor can be fully operable and wait, for example, for a voice input (step  360 ), and based on the determined voice input, can either unlock the display screen or execute a function or application (step  370 ). For further purposes of illustration and not to limit the claimed invention, exemplary protocol between the main processor and sub-processor is discussed herein. The protocol for transmitting is in accordance with the main processor and sub-processor&#39;s active or sleep state. 
     As shown in  FIG. 3B , while the main processor is active, an exchange occurs between main processor and a sub-processor according to a HUB protocol. First, a hub interrupt is sent by the main processor to the sub-processor, and wherein the main processor starts to send length information. In turn, the sub-processor sends an acknowledgement back to the main processor. At this point, the hub (sub-processor) sets the control right and AP sleep information. 
     With continued reference to  FIG. 3B , it can be seen that the sub-processor keeps varying states between active and sleep. When a situation arise where the main processor needs to be awakened, an AP interrupt id from the sub-processor to the main processor. Once the main processor is awakened, the main processor remains in an active state and starts to send information to the sub-processor. In turn, the sub-processor indicates to the main processor the data length to send. Next the main processor starts to read a message from sub-processor, which can comprise sensor data and sub-processed data. 
       FIG. 3C  shows an example of a main processor to sub-processor (i.e. AP to Hub Protocol Message Frame) that can be used according to an exemplary aspect of the present invention. 
     Referring now to  FIG. 3C , it is shown that an exemplary frame can be 8 bytes, with a command field commanded by the AP (main processor) to the Hub (sub-processor), a sensor number field specifying a particular sensor, s data type showing the content of the operand being transmitted, a data size field providing the actual data that follows. Each of the aforementioned parts of the message frame can be 1 byte in length, and the data and status can be 4 bytes each so as to total 8 bytes, for example. 
       FIG. 3D  shows another example of AP (main processor) to Hub (Sub-processor Protocol according to a non-limiting exemplary aspect of the present invention. These actions are similar to what is shown in  FIG. 3B  while the AP is in the active mode. 
       FIG. 4  shows a flowchart illustrating exemplary operation of a signature unlock based on stylus movement according to an exemplary aspect of the invention. 
     With reference to  FIG. 4 , at step  400 , the main processor and sub-processor are in sleep mode. At step  410 , the presence of a stylus pen  475  is monitored to determine whether the stylus pen has been removed from a holder on the electronic device. At step  420 , when it is determined that the stylus pen is removed, sub-processor wakes up at  430 . If at step  440 , the non-input timer has expired, the main processor and sub-processor go back to sleep mode, otherwise, at step  450  it is determined whether a signature is valid, and if so, then main processor wakes up, and the display LCD is turned on and unlocked (step  460 ). 
       FIG. 5  shows a current profiling example according to an exemplary aspect of the invention. In this particular non-limiting example, The X axis is time, and the Y-axis is current consumption which comprises milliamps and microamps. 
     As shown in  FIG. 5 , the IR gesture sensor (interrupt sensor) consumes at 317.5 uA of current. The sub-processor in this example consumes about 3.2 uA when awakened due to the IR gesture sensor sensing a change in the ambient condition. Within about 330 ms of waking up the sub-processor may wake up the main processor to perform a function, and upon doing so, the sub-processor goes back to sleep. The main processor consumes considerably more current than the sub-processor. Also, in the example of  FIG. 5 , it is shown that the accelerometer can cause the main processor to wake up within 180 ms. 
       FIG. 6  shows one possible example of a wireless device incorporating the present invention. An artisan understands and appreciates that a plurality of both wired and wireless devices can benefit from the claimed invention. Some non-limiting examples include smartphone, tablet, PDA, music player, etc. just to name a few examples. A controller includes the main processor  610  and a codec  617 , the controller communicates with sensing processor  620 . The interrupt sensor  630  and the polling sensor  640  are shown schematically, but their actual proximity to the controller us likely to be different than shown. 
     Touch screen  655  permits display and entry of data. Storage device  685  is in communication with the controller, and comprises a non-transitory machine readable medium. 
     Auxiliary input  675  can be anything from a keyboard to a mouse, and wireless communication device, shown as a single box, may be different hardware modules for transmitting in short range communication such as Near Field Communication, Bluetooth, WLAN, 802.11, RF communications, etc. 
     In the invention, the ambient environment is monitored by an interrupt sensor, so that the sub-processor and the main processor (application processor) can remain together in sleep mode. Not only does the invention save power, but provides the user with a convenience in that there is no requirement to push a button to activate/convert the device from a sleep mode back to a normal operating mode. 
     The sensing of a swiping near the device is sufficient to awake the device from sleep mode, or alternatively, shaking or waving the device, also restores the device to a normal operating state by waking it up. 
     The above-described methods according to the present invention can be implemented in hardware, firmware or as software or computer code that can be stored in a recording medium such as a CD ROM, an RAM, a floppy disk, a hard disk, or a magneto-optical disk or computer code downloaded over a network originally stored on a remote recording medium or a non-transitory machine readable medium and to be stored on a local recording medium, so that the methods described herein can be rendered in such software that is stored on the recording medium using a general purpose computer, or a special processor or in programmable or dedicated hardware, such as, flash, an ASIC or FPGA. As would be understood in the art, the computer, the processor, microprocessor controller or the programmable hardware include memory components, e.g., RAM, ROM, Flash, etc. that may store or receive software or computer code that when accessed and executed by the computer, processor or hardware implement the processing methods described herein. In addition, it would be recognized that when a general purpose computer accesses code for implementing the processing shown herein, the execution of the code transforms the general purpose computer into a special purpose computer for executing the processing shown herein.