Patent Publication Number: US-2012033820-A1

Title: Audio player

Description:
BACKGROUND 
     1. Technical Field 
     The disclosed embodiments relate to audio players. 
     2. Description of Related Art 
     An audio player, such as portable MP3 player, DVD player, etc. is used for playing audio files and outputting sound through a speaker. When the volume of the speaker is too high and the high volume is sustained for a long time, the temperature of the speaker may get too high, thus the speaker may be damaged, and further, some electronic components of the audio player may be damaged. 
     What is needed, therefore, is an audio player and an electronic device to overcome the above described limitations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout one view. 
       The FIGURE is a circuit diagram of an audio player in accordance with one embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , an electronic device  100  includes a memory  10 , a reading unit  12 , a processing unit  13 , a protection unit  18 , and a speaker  20 . The memory  10  stores a plurality of audio files. In this embodiment, the electronic device  100  is an audio player. In other embodiments, the memory  10  is an external storage medium and is not included in the audio player  100 , such as an optical disc. 
     The reading unit  12  is used for acquiring an audio file stored in the memory  10 . The processing unit  13  is used for processing the acquired audio file to generate an audio signal. In detail, the processing unit  13  includes a decoder  14 , a coupling circuit  15 , and a power amplifier  16 . The decoder  14  decodes the acquired audio file to generate the audio signal. The power amplifier  16  amplifies the audio signal and provides the amplified audio signal to the speaker  16  through the protection unit  18 . The coupling circuit  15  is used for filtering the DC portion of the audio signal transmitted from the decoder  14  to the power amplifier  16 . In this embodiment, the coupling circuit  15  includes a coupling capacitor  15  connected between the decoder  14  and the power amplifier  16 . 
     The speaker  20  is used for reproducing the amplified audio signal. The protection unit  18  is connected between the processing unit  13  and the speaker  20 , and is used for detecting temperature changes of the speaker  20 . An internal resistance of the protection unit  18  is automatically adjusted according to temperature changes of the speaker  20  to adjust a current of the audio signal flowing from the power amplifier  16  to the speaker  20 . In detail, when the temperature of the speaker  20  increases, the internal resistance of the protection unit  18  also increases, therefore the current of the audio signal flowing from the power amplifier  16  to the speaker  20  decreases, and the temperature of the speaker  20  will decrease. Therefore, the damage of the speaker  20  is effectively prevented. 
     Furthermore, when the temperature of the speaker  20  decreases, the internal resistance of the protection unit  18  also decreases, therefore the electric energy consumed by the protection unit  18  is reduced, the power efficiency of the audio player  100  is enhanced. In detail, the protection unit  18  includes a thermal resistor R, the thermal resistor R is connected in series between the power amplifier  16  and the speaker  20 . When the temperature of the speaker  20  is increased, the resistance of the thermal resistor R is also increased. When the temperature of the speaker  20  is decreased, the resistance of the thermal resistor R is also decreased. 
     Alternative embodiments will become apparent to those skilled in the art without departing from the spirit and scope of what is claimed. Accordingly, the present invention should be deemed not to be limited to the above detailed description, but rather only by the claims that follow and equivalents thereof.