Patent Publication Number: US-9904812-B2

Title: Method of protecting power receiver and related wireless charging device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a divisional application of application Ser. No. 14/188,656, which claims the benefit of U.S. Provisional Application No. 61/768,373, and U.S. Provisional Application No. 61/834,890, the contents of which are included in its entirety herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a method used in a wireless charging system and related wireless charging device, and more particularly, to a method of improving the security of the power receiver in a wireless charging system and related wireless charging device. 
     2. Description of the Prior Art 
     With the proliferation of portable electronic devices such as smart phone and tablet PC, the demand for charging devices, especially for those provided in public areas, is increasing. In addition, people would like to get rid of annoying wires if possible. One technology which realizes this desire is wireless charging, in which mobile device(s) (i.e. power receiver) is placed on and charged through a charging device (i.e. power transmitter). Therefore, the current trend is towards providing wireless charging in public areas so that people can easily find a wireless power supply to charge their portable electronic devices. 
     Wireless Power Consortium (WPC) is a leading organization in the world to define wireless charging specification. The document Wireless Power Transfer—Volume I, part I in version 1.1.1 released in July 2012 has specified the communication protocol between a power transmitter and a power receiver. In section 5.3.3, it defines that the power receiver shall transmit the following sequence of packets:
         1. An Identification Packet, which includes an identity of the power receiver if the power receiver enters an identification and configuration phase from the ping phase.   2. An Extended Identification Packet, if the Ext bit of the preceding Identification Packet is set to ONE.   3. Up to 7 Optional Configuration Packets.   4. A Configuration Packet, where the second byte (B1) and the fifth byte (B4) of the Configuration Packet are reserved bytes, and the 4 bits (b6-b3) in the third byte (B2) are reserved bits.       

     On the other hand, the specification defines that the power receiver shall transmit zero or more of the Control Error Packet, the Received Power Packet, the Charge Status Packet, the End Power Transfer Packet, and Any Proprietary Packet. If the power transmitter does not know how to handle the message contained in the Proprietary Packet, the power transmitter shall ignore that message. 
     Furthermore, the specification defines that at any time a user can remove a Mobile Device that is receiving power. The power transmitter can recognize such an event from a time-out in the communications from the power receiver or from a violation of the Power Transfer Contract. In addition, the power receiver may stop transmitting packets to the power transmitter at any time. 
     From the above description, the specification defines that the Identification Packet is sent from Power Receiver to the power transmitter only once at the identification and configuration phase, and it supports to remove the power receiver at any time. But how the power transmitter knows the power receiver is removed by the owner or by the others is not sure. As people place their mobile devices on a power transmitter, they may not always keep an eye on them. In such a situation, the mobile devices might be taken away by other people without permission. 
     Therefore, how to secure the power receiver while the power receiver performs wireless charging publicly is a topic to be addressed and discussed in the industry. 
     SUMMARY OF THE INVENTION 
     An objective of the present invention is to provide a method and related wireless charging system capable of protecting the power receiver from being taken without permission. 
     The present invention discloses a method for a power receiver for protecting the power receiver from being taken without permission while charged wirelessly includes receiving wireless power from a power transmitter and performing wireless charging in a security mode by the power receiver; detecting whether the wireless charging is interrupted without receiving a security code for authorization; and starting a protection function if the power receiver detects that the wireless charging is interrupted without receiving the security code for authorization. 
     The present invention further discloses a power receiver, which includes a processing means, for executing a program; and a storage unit, coupled to the processing means, for storing the program which instructs the processing means to perform the following steps, for protecting the power receiver from being taken without permission while charged wirelessly: receiving wireless power from a power transmitter and performing wireless charging in a security mode; detecting whether the wireless charging is interrupted without receiving a security code for authorization; and starting a protection function if the wireless charging is detected to be interrupted without receiving the security code for authorization. 
     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 schematic diagram of a wireless charging system according to an example of the present invention. 
         FIG. 2  is a schematic diagram of a wireless charging system according to an example of the present invention. 
         FIG. 3  is a flowchart of a process according to an example of the present invention. 
         FIG. 4  is a schematic diagram of a wireless charging system according to an example of the present invention. 
         FIG. 5A  is a flowchart of a process according to an example of the present invention. 
         FIG. 5B  is a flowchart of a process according to an example of the present invention. 
         FIG. 6  is a schematic diagram of a wireless charging system according to an example of the present invention. 
         FIG. 7A  is a flowchart of a process according to an example of the present invention. 
         FIG. 7B  is a flowchart of a process according to an example of the present invention. 
         FIG. 8  is a schematic diagram of a configuration packet according to an example of the present invention. 
         FIG. 9  is a schematic diagram of an end power transfer packet according to an example of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Please refer to  FIG. 1 , which illustrates a schematic diagram of a wireless charging system  10  according to an example of the present disclosure. A wireless charging system may include at least one power transmitter and at least one power receiver. For simplicity, in  FIG. 1 , the wireless charging system  10  is briefly composed of a power transmitter  100  and a power receiver  120 . The power transmitter may represent a power base station, or a power transmitting module including digital/analog chip(s), to supply wireless power. The power receiver may be a mobile phone, a laptop, a tablet computer, an electronic book, a portable computer system, any other mobile devices or at least a power receiving module. Alternatively, the power receiver  120  may be any electronic device using battery as its power supply, such as a wearable computing device, a wearable medical device, a portable MP3 player, etc. The power receiver  120  may directly attach to the power transmitter  100  or keep within a distance from the power transmitter  100  for wireless charging. As shown in  FIG. 1 , the power receiver  120  receives wireless power from the power transmitter  100  by electromagnetic induction, so as to charge the battery of the power receiver  120  without using any wire connection. 
     Please refer to  FIG. 2 , which is a schematic diagram of a wireless charging system  20  according to an example of the present invention. The wireless charging system  20  includes a power transmitter  200  and a power receiver  220 . The power transmitter  200  may be the power transmitter  100  shown in  FIG. 1 , and the power receiver  220  may be the power receiver  120  shown in  FIG. 1 . The power transmitter  200  may include a power supply controller  202  and a wireless power transmitting unit  204 . The power supply controller  202 , such as a microcontroller or an Application Specific Integrated Circuit (ASIC), generally handles signals transmitted/received from the power receiver  200 , so as to control the wireless power transmitted by the wireless power transmitting unit  204 . The power receiver  220  may include a processing means  222  such as a microprocessor or an ASIC, a wireless power receiving unit  224 , a battery unit  226 , a communication interface  228 , a user interface  230 , a program interface  232 , and an interruption detecting unit  234 . The wireless power receiving unit  224  receives the wireless power from the power transmitter  200  to charge the battery unit  226 . The communication interface  228  is preferably a radio transceiver that transmits and receives radio signals (e.g., messages, emails, or packets) according to processing results of the processing means  222 . In addition, the communication channel between the power transmitter  200  and the power receiver  220  may be an in-band communication channel (e.g. by using load modulation), in which communication signals are carried by the wireless power. Alternatively, the communication channel between the power transmitter  200  and the power receiver  220  may be an out-band communication channel (e.g. by using a short-range communication protocol such as Bluetooth). The user interface  230  may include a touch panel, keyboard, button, microphone, camera, fingerprint identity sensor, a gesture sensor, or any interface that can receive user inputs. The program interface  232  may be an application program interface, which receives a command or a control signal from the processing means  222  to launch a function or control an application provided by the power receiver  220 . The interruption detecting unit  234  may be coupled to the power receiving unit  224  for real-time detecting whether the wireless power received by the power receiving unit  224  is interrupted. 
     Please refer to  FIG. 3 , which is a flowchart of a process  30  according to an example of the present invention. The process  30  is utilized for a wireless charging system, such as the wireless charging system  20  shown in  FIG. 2 , to protect a power receiver from being taken without permission while charged wirelessly and thus improve the security of the power receiver. The power receiver could be the power receiver  220  in the wireless charging system  20 , but is not limited herein. The process  30  may be implemented by the power receiver  220  and compiled into a program code to instruct the processing means  222  to execute the following steps: 
     Step  300 : Start. 
     Step  302 : Receive wireless power from the power transmitter  200  and perform wireless charging in a security mode. 
     Step  304 : Detect whether the wireless charging is interrupted without receiving a security code for authorization. 
     Step  306 : Start a protection function if the power receiver  220  detects that the wireless charging is interrupted without receiving a security code for authorization. 
     Step  308 : End. 
     According to the process  30 , an owner of the power receiver  220  may configure the power receiver  220  to perform wireless charging in the security mode. The owner may define a specific contour or drawing, a snapshot, a series of numbers and/or alphabets and/or symbols, a voice message including specific words or sentences, a gesture, a fingerprint, an image of a human face or a part of the body, or any of their combinations as the security code of the security mode. When the power receiving unit  224  performs wireless charging, the interruption detecting unit  234  continuously detects whether the wireless power is interrupted (i.e. the power receiver  220  is removed from the power transmission coverage of the power transmitter  200 ) and generates a detection result for the processing means  222 . If the detection result indicates that the wireless charging is interrupted but a user input matching with the security code has not been received within a certain period (e.g. 5 seconds), the processing means  222  determines that an unauthorized interruption occurs and the power receiver  220  might be stolen. In response, the power receiver  200  may start the protection function as an action to protect the power receiver  220  from being taken without permission. For example, the protection function may be a function for releasing a warning signal to notify an owner of a power receiver theft. The warning signal may be in a form of a beep, a noisy sound, video, audio, image, and/or a bright light which is activated via the program interface  232  to draw the owner&#39;s attention. As a result, the present invention can prevent the charging receiver  220  from being taken without permission in a public space. 
     Note that the process  30  is an example of the present invention. Those skilled in the art should readily make combinations, modifications and/or alterations on the abovementioned description and examples. For example, after the unauthorized interruption is detected, the power receiver  220  may also launch a function or an application for reporting a location of the power receiver  220  through the program interface  232 . In this way, the owner may track the lost power receiver  220  and manage to find it easily. In addition, another function or application may automatically send a loss notification to a specific person and/or a place for help. The example of the loss notification may be a message or an email sent via the communication interface  228 . The example of the specific person and/or the place may be the owner of the power receiver  220 , an owner who provided the power transmitter  200  such as a coffee shop or an airport, the front desk of the coffee shop, or a police station nearby. 
     In another example, the power transmitter may have the capability to warn the owner about the power receiver theft as well. Please refer to  FIG. 4 , which is a schematic diagram of a wireless charging system  40  according to an example of the present invention. The wireless charging system  40  includes a power transmitter  400  and a power receiver  420 . Comparing to the wireless charging system  20  shown in  FIG. 2 , the power transmitter  400  may additionally include an output unit  406  and/or a communication interface  408 . The output unit  406  may include a speaker, a light-emitted diode (LED), a screen, or a vibrator. The communication interface  408  may be a radio transceiver that can transmit and receive radio signals (e.g., messages, emails, or packets) according to a control signal of the power supply controller  402 . 
     Please refer to  FIG. 5A , which is a flowchart of a process  50 A according to an example of the present invention. The process  50 A is utilized for a wireless charging system, such as the wireless charging system  40  shown in  FIG. 4 , to protect a power receiver from being taken without permission while charged wirelessly and thus improve the security of the power receiver. The power receiver could be the power receiver  420  in the wireless charging system  40 , but is not limited herein. The process  50 A may be implemented by the power receiver  420  and compiled into a program code to instruct the processing means  422  to execute the following steps: 
     Step  500 A: Start. 
     Step  502 A: Receive wireless power from the power transmitter  400  and perform wireless charging in a security mode. 
     Step  504 A: Detect whether the wireless charging is interrupted without receiving a security code for authorization. 
     Step  506 A: Send an unauthorized interruption notification signal to the power transmitter  400  after the power receiver  420  detects that the wireless charging is interrupted without receiving the security code for authorization. 
     Step  508 A: End. 
     Please refer to  FIG. 5B , which is a flowchart of a process  50 B according to an example of the present invention. The process  50 B is the corresponding actions of the process  50 A for the power transmitter  400 . The process  50 B may be implemented by the power supply controller  402  of the power transmitter  400  to execute the following steps: 
     Step  500 B: Start. 
     Step  502 B: Transmit wireless power to the power receiver  420 . 
     Step  504 B: Start a protection function after the unauthorized interruption notification signal is received. 
     Step  506 B: End. 
     According to the processes  50 A and  50 B, an owner of the power receiver  420  may configure the power receiver  420  to perform wireless charging in the security mode. The owner may define a specific contour or drawing, a snapshot, a series of numbers and/or alphabets and/or symbols, a voice message including specific words or sentences, a gesture, a fingerprint, an image of a human face or a part of the body, or any of their combinations as the security code of the security mode. When the power receiving unit  424  performs wireless charging, the interruption detecting unit  434  continuously detects whether the wireless power is interrupted (i.e. the power receiver  420  is removed from the power transmission coverage of the power transmitter  400 ) and generates a detection result for the processing means  422 . If the detection result indicates that the wireless charging is interrupted but a user input matching with the security code has not been received within a certain period (e.g. 5 seconds), the processing means  222  may send an unauthorized interruption notification signal to the power transmitter  400 . In such a situation, the power transmitter  400 , or both the power transmitter  400  and the power receiver  420 , can determine that an unauthorized interruption occurs and the power receiver  420  might be stolen, thereby starting the protection function such as releasing a warning signal in a form of a beep, a noisy sound, video, audio, image, and/or a bright light to draw the owner&#39;s attention. 
     In addition, the power receiver  420  may also launch a function or an application for reporting a location of the power receiver  420  for searching the lost power receiver  420 . Furthermore, the power transmitter  400  and/or the power receiver  420  may send a loss notification (e.g. a message or an email) to a specific person (e.g. the owner of the power receiver  420 , an owner or the front desk of a place where the power transmitter  400  is provided such as a coffee shop, a train station, a restaurant or an airport) and/or a place (e.g. a police station nearby) for help via the communication interface  408 / 428 . 
     In another example, the unauthorized interruption is detected by a power transmitter. Please refer to  FIG. 6 , which is a schematic diagram of a wireless charging system  60  according to an example of the present invention. The wireless charging system  60  includes a power transmitter  600  and a power receiver  620 . Comparing to the wireless charging system  40  shown in  FIG. 4 , the power transmitter  600  additionally includes an interruption detecting unit  610  and the power receiver  620  is not necessarily to include an interruption detecting unit. In this example, the power transmitter  600  may transmit wireless power to the power receiver  620  for wireless charging, and constantly detect whether the wireless charging is interrupted. If the power transmitter  600  detects that the wireless charging is interrupted, it start may a protection function so as to protect the power receiver  220  from being taken without permission. 
     Please refer to  FIG. 7A , which is a flowchart of a process  70 A according to an example of the present invention. The process  70 A is utilized for a wireless charging system, such as the wireless charging system  60  shown in  FIG. 6 , to protect a power receiver from being taken without permission while charged wirelessly and thus improve the security of the power receiver. The power receiver could be the power receiver  620  in the wireless charging system  60 , but is not limited herein. The process  70 A may be implemented by the power supply controller  602  of the power transmitter  600  to execute the following steps: 
     Step  700 A: Start. 
     Step  702 A: Transmit wireless power to the power receiver  620  for performing wireless charging. 
     Step  704 A: Receive a notification from the power receiver  620  that indicates the power receiver  620  is going to perform wireless charging in a security mode. 
     Step  706 A: Detect whether the wireless charging is interrupted. 
     Step  708 A: Start a protection function if the power transmitter  600  detects that the wireless charging is interrupted and an authorized remove notification signal has not been received from the power receiver  620 . 
     Step  710 A: End. 
     Please refer to  FIG. 7B , which is a flowchart of a process  70 B according to an example of the present invention. The process  70 B is the corresponding actions of the process  70 A for the power receiver  620 . The process  70 B may be implemented by the power receiver  620  and compiled into a program code to instruct the processing means  622  to execute the following steps: 
     Step  700 B: Start. 
     Step  702 B: Receive wireless power from the power transmitter  600  and perform wireless charging. 
     Step  704 B: Notify the power transmitter  600  that the power receiver  620  is going to perform wireless charging in a security mode. 
     Step  706 B: Send an authorized remove notification signal to the power transmitter  600  if the power receiver  620  receives a security code while being removed from the power transmitter  600 . 
     Step  708 B: End. 
     According to the processes  70 A and  70 B, an owner of the power receiver  620  may configure the power receiver  620  to perform wireless charging in the security mode. The owner may define a specific contour or drawing, a snapshot, a series of numbers and/or alphabets and/or symbols, a voice message including specific words or sentences, a gesture, a fingerprint, an image of a human face or a part of the body, or their combination as the security code of the security mode. During performing wireless charging, the power receiver  620  may notify the power transmitter  600  that the power receiver  620  is going to perform the wireless charging in the security mode. When the wireless power transmitting unit  604  transmits wireless power, the interruption detecting unit  610  constantly detects whether the wireless power is interrupted (i.e. the power receiver  620  is removed from the power transmission coverage of the power transmitter  600 ) and generates a detection result for power supply controller  602 . On the other hand, when the owner of the power receiver  620  intends to terminate the wireless charging, the owner enters the security code to unlock the security mode. Accordingly, the power receiver  620  may send an authorized remove notification signal to the power transmitter  600 . If the detection result indicates that the wireless charging is interrupted and the power transmitter  600  receives the authorized remove notification signal, the power supply controller  602  determines that the power receiver  620  is removed with permission. Otherwise, if the detection result indicates that the wireless charging is interrupted but the power transmitter  600  has not receive the authorized remove notification signal from the power receiver  620  within a certain period (e.g. 4 seconds), the power supply controller  602  determines that the unauthorized interruption occurs. In such a situation, the power transmitter  400  may determine that the power receiver  620  might be stolen, and therefore, start a protection function such as releasing the warning signal to draw the owner&#39;s attention and/or sending a loss notification (e.g. a message or an email) to a specific person to find help. 
     In an example, the power receiver  620  may constantly send a feedback to the power transmitter  600 . Accordingly, the power transmitter  600  may detect that the wireless charging is interrupted if not receiving the feedback for more than a specific time. The feedback may be sent periodically or non-periodically. The feedback may be included in a control error packet (CEP) for sending to the power transmitter  600  during wireless charging. 
     In an example, the power receiver  620  may notify the power transmitter  600  that the power receiver  620  is going to perform the wireless charging in the security mode by a bit included in a configuration packet, during an identification and configuration phase which is a period for initializing the wireless charging.  FIG. 8  illustrates a schematic diagram for a configuration packet  80  according to an example of the present invention. As shown in  FIG. 8 , the configuration packet  80  includes a bit  800  which notifies the power transmitter  600  that the power receiver  620  is going to perform the wireless charging in the security mode. 
     The authorized remove notification signal may be realized by an end power transfer packet with a message code indicating that the power receiver  620  is removed with authorization.  FIG. 9  illustrates a schematic diagram for an end power transfer packet  90  according to an example of the present invention. As shown in  FIG. 9 , the end power transfer packet  90  is defined with a specific message code (e.g., 0x0B or else) to indicate that the power receiver  620  is removed with authorization. 
     In another example, the owner of the power receiver  620  may set the power receiver  620  on the power transmitter  600  before configuring the power receiver  620  to perform wireless charging in the security mode. Under this condition, the configuration packet  80  may have been sent to the power transmitter  600  already, so the power receiver  620  may send an end power transfer packet with a message code indicating ‘Re-configure’ and then send the configuration packet  80  for notifying the power transmitter  600  that the security mode is going to used. 
     If the owner takes the power receiver  620  away from the power transmitter  600  without entering the security code of the security mode and thus induces the protection functions (e.g. releasing the warning signal, sending a loss notification, or reporting the location of the power receiver  620 ) of the wireless charging system  60 , the owner can replace the power receiver  620  on the power transmitter  600 . In such a situation, the power receiver  620  may send an identification packet to the power transmitter  600 . If the power transmitter  600  finds that the identity if the replaced power receiver  620  is consistent with the previous one before the interruption, it may stop the protection functions. 
     In another example, the power transmitter  600  may send an unauthorized interruption notification signal to the power receiver  620  after detecting the unauthorized interruption. Therefore, the power receiver  620 , or both the power transmitter  600  and the power receiver  620 , may determine that the power receiver  620  might be stolen, thereby activating the protection functions (e.g. releasing a warning signal to notify an owner of a power receiver theft, launching a function for reporting a location of the power receiver, and/or sending a message to a specific person or a place for help). 
     The abovementioned steps of the processes  30 ,  50 A,  50 B,  70 A, and  70 B including suggested steps may be realized by means of hardware, software, firmware, or an electronic system. Examples of hardware may include analog, digital and mixed circuits known as microcircuit, microchip, or silicon chip. Examples of the electronic system may include a system on chip (SOC), system in package (SiP), and a computer on module (COM). 
     To sum up, the present invention provides a security mode (i.e. in addition to a normal charging mode) for charging in a public space. After the unauthorized interruption of the wireless charging is detected, the protection functions such as releasing the warning signal, sending a loss notification, and functions to track the power receiver are activated, thus preventing the power receiver from being stolen. 
     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. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.