Abstract:
A power adjusting module applied in a wearable device and includes a sensor, a central processing unit (CPU). The sensor triggers a detect signal. The CPU determines if the wearable device is in a wearing mode or a free mode according to the detect signal. If the wearable device is determined in a wearing mode, the CPU generates an instruction for increasing a transmission power of an antenna of the wearable device; if the wearable device is determined in a free mode, the CPU generates an instruction for decreasing the transmission power of the antenna. A wearable device employing the power adjusting module is also provided.

Description:
FIELD 
       [0001]    The subject matter herein generally relates to a power adjusting module and a wearable device employing the power adjusting module. 
       BACKGROUND 
       [0002]    Wearable devices need to be processed a specific absorption rate (SAR) test when manufactured. Decreasing a radiating power of an antenna of the wearable device, maintaining a radiating efficiency, and meeting a SAR test standard are still problems to be solved in the art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0003]    Many aspects of the disclosure can be better understood with reference to the following figures. The components in the figures are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
           [0004]      FIG. 1  is an isometric view of one embodiment of a wearable device. 
           [0005]      FIG. 2  is a block diagram of one embodiment of a power adjusting module. 
       
    
    
     DETAILED DESCRIPTION 
       [0006]    It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures and components have not been described in detail so as not to obscure the related relevant feature being described. Also, the description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts may be exaggerated to better illustrate details and features of the present disclosure. 
         [0007]    The term “comprising,” when utilized, means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in the so-described combination, group, series and the like. 
         [0008]      FIG. 1  illustrates one embodiment of a wearable device  100  can be coupled to a wrist of a user. The wearable device  100  can be a watch and a bracelet. The wearable device  100  includes a body  10 , a screen  20 , a cover  30  and a wearable portion  40 . 
         [0009]    The screen  20  and the cover  30  are arranged on opposite sides of the body  10 . The wearable portion  40  may be coupled to the cover  30  and extended from opposite ends of the cover  30 . The wearable portion  40  is detachably worn to the wrist of the user, while the screen  20  faces to the user for providing information. 
         [0010]      FIG. 2  illustrates that the wearable device  100  further includes a power adjusting module  11  and a radio frequency (RF) antenna  12 . The power adjusting module  11  includes a sensor  13  and a central processing unit (CPU)  14 . The RF antenna  12  is configured for transmitting and receiving RF signals. The sensor  13  is configured for triggering a detect signal and transmitting to the CPU  14 . The CPU  14  is configured for determining if the wearable device  100  is in a wearing mode or a free mode according to the detect signal. If the wearable device  100  is in the wearing mode, the CPU  14  controls the RF antenna  12  to increase a transmission power. If the wearable device  100  is in the free mode, the CPU  14  controls the RF antenna  12  to decrease a transmission power. In at least one embodiment, the RF antenna  12 , the sensor  13  and the CPU  14  can be received in the body  10 . In other embodiments, the RF antenna  12  can be integrated with the cover  30  which is made of metal material; the sensor  13  can be coupled to the cover  30 . 
         [0011]    In a first embodiment, the sensor  13  is a gravity sensor configured for detecting acceleration of the wearable device and the detect signal is an acceleration signal. When the wearable device  100  is worn by the user, the sensor  13  may generate different acceleration signals according to movements of the user and further transmits the acceleration signals to the CPU  14 . The CPU  14  determines the wearable device  100  is in the wearing mode according to the acceleration signals. When the wearable device  100  is not worn by the user, the sensor  13  may not trigger acceleration signals since the wearable device  100  is not moved with the user. The CPU  14  may not receive any acceleration signal and determines the wearable device  100  is in the free mode. 
         [0012]    In a second embodiment, the sensor  13  is a light sensor, which includes a light emitting diode (LED) and a light receiver. The LED is configured for transmitting light toward the wrist wearing the wearable device  100  and the light receiver is configured for receiving light reflected from the wrist. When the user is wearing the wearable device  100 , the wrist may block the light path transmitted by the LED, the light receiver receives the reflected lights reflected by the wrist and transmits an electronic signal to the CPU  14 . The CPU  14  determines the wearable device  100  is in the wearing mode according to the electronic signal. When the user is not wearing the wearable device  100 , the light receiver may not receive reflected lights, then the CPU  14  may not receive any signals from the sensor  13  and determines the wearable device  100  is in the free mode. 
         [0013]    In a third embodiment, the sensor  13  is a pulse wave sensor, such as an infrared pulse wave sensor and a photoelectric pulse wave sensor. The pulse wave sensor includes an infrared LED and an infrared photo transistor. The infrared LED is configured for transmitting infrared ray toward the wrist wearing the wearable device  100 . When the user is wearing the wearable device  100 , the wrist may block the infrared ray transmitted by the infrared LED, when the infrared ray reach blood vessels of the wrist and part of the infrared ray may be reflected by the blood vessels, the infrared photo transistor receives the reflected infrared ray reflected by the blood vessels and transmits an electronic signal to the CPU  14 . The CPU  14  determines the wearable device  100  is in the wearing mode according to the electronic signal. When the user is not wearing the wearable device  100 , the infrared photo transistor may not receive reflected infrared ray, then the CPU  14  may not receive any signals from the sensor  13  and determines the wearable device  100  is in the free mode. 
         [0014]    In a fourth embodiment, the sensor  13  is a cardiogram sensor, which includes an electrode tab arranged on the cover  30 . When the user is wearing the wearable device  100 , the wrist contacts the electrode tab on the cover  30 , the electrode tab detects movement electric potential of the heart of the user and the sensor  13  transmits an electronic signal to the CPU  14  according to the detected movement electric potential signal. The CPU  14  determines the wearable device  100  is in the wearing mode according to the electronic signal. When the user is not wearing the wearable device  100 , the sensor  13  may not detect any movement electric potential signal, then the CPU  14  may not receive any signals from the sensor  13  and determines the wearable device  100  is in the free mode. 
         [0015]    The wearable device  100  may use only one of the aforesaid sensors  13  or a combination of the sensor  13  to trigger the detect signals. If wearable device  100  uses multiple sensors  13 , when all the sensors  13  and the CPU  14  determine a same result for the wearing mode or the free mode, the determination is valid. When the sensors  13  and the CPU  14  determine different result for the wearing mode or the free mode, the determination is invalid, the sensors  13  and the CPU  14  may restart determining again. 
         [0016]    The wearable device  100  includes the sensor  13  and the CPU  14  for determining if the wearable device  100  is in the wearing mode or in the free mode, thus to adjust the transmission power of the RF antenna  12  according to the status of the wearable device  100 , thereby maintaining a radiating efficiency and meeting a specific absorption rate (SAR) test standard. 
         [0017]    It is believed that the embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the scope of the disclosure or sacrificing all of its advantages, the examples hereinbefore described merely being illustrative embodiments of the disclosure.