Patent Publication Number: US-2007121981-A1

Title: Portable speaker of portable multimedia device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      This application claims priority under 35 U.S.C. §119(a) from Korean Patent Application No. 10-2005-0113861, filed on Nov. 26, 2005, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present general inventive concept relates to a portable speaker of a portable multimedia device.  
      2. Description of the Related Art  
      As a variety of portable multimedia devices are being commercialized and developed, users can enjoy a variety of multimedia anywhere and at anytime.  
      In order to listen to a music or audio signal of a movie from a conventional multimedia device, a user generally uses an earphone or a built-in speaker of the multimedia device.  
      For example, as illustrated in  FIG. 1A , an audio signal may be output through a built-in speaker  110  of a portable multimedia device  100 .  
      Alternatively, as illustrated in  FIG. 1B , the audio signal may be output through an earphone  120  connected to the portable multimedia device  100 .  
      As described above, since a user listens to the sound from the portable multimedia device  100  through the earphone  120  or built-in speaker  110 , the user cannot enjoy a high-quality sound, a space feeling, or a virtualizer effect (e.g., a surround-sound effect).  
      Also, when a user uses the portable multimedia device  100  at an outdoor site for a long period of time, and thus an internal battery thereof becomes fully discharged, the user cannot use the portable multimedia device  100  until the internal battery is recharged or replaced with a new battery resulting in an inconvenience to the user.  
      As described above, one of the drawbacks of a portable multimedia device, such as an MP3 player or a portable multimedia player (PMP), is that the device has only an earphone output without a speaker output. Even when the portable multimedia device has a built-in speaker system, the performance of the speaker system is very low. It is very difficult to install a high quality audio amplifier or speaker unit in a limited space of the portable multimedia device that is minimized in size and has a variety of functions. Therefore, a low quality audio amplifier or speaker unit that can be designed to have a relatively small size is applied to the portable multimedia device. Thus, many built-in speakers applied to portable multimedia devices output a mono-sound. On the other hand, when a built-in speaker outputs a stereo-sound, an internal battery thereof is quickly discharged due to a low performance of the built-in stereo-sound speaker.  
      Therefore, there is a need for a portable speaker that can be used when a user wishes to enjoy a high quality sound from a multimedia device and can function as an external battery pack for the multimedia device.  
     SUMMARY OF THE INVENTION  
      The present general inventive concept provides a portable speaker to output a high quality sound signal including a variety of three-dimensional sound signals from a portable multimedia device.  
      The present general inventive concept also provides a portable speaker to function as an external battery pack to supply electric power to the multimedia device.  
      Additional aspects and advantages of the present general inventive concept will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the general inventive concept.  
      The foregoing and/or other aspects and utilities of the present general inventive concept may be achieved by providing a portable speaker of a portable multimedia device, including a digital amplifier to receive a digital audio signal from the portable multimedia device and to digitally process and output the received digital audio signal to a speaker unit, and a battery to supply electric power to at least one of the digital amplifier and the portable multimedia device.  
      The battery may always supply the electric power to the portable multimedia device when the portable speaker is connected to the portable multimedia device.  
      The battery may supply the electric power to the portable multimedia device only when an internal battery of the portable multimedia device is fully discharged and the portable speaker is connected to the portable multimedia device.  
      The portable speaker may further include a virtualizer to provide a sound field effect to the audio signal, and a dynamic range controller to prevent a clipping of the audio signal.  
      The foregoing and/or other aspects and utilities of the present general inventive concept may also be achieved by providing a portable speaker unit useable with a multimedia device, including a processing unit to process a digital audio signal received from the multimedia device and to output an audio analog signal corresponding to the received digital audio signal, at least one speaker to receive the audio analog signal from the processing unit and to output sound corresponding to the audio analog signal, and a battery unit to supply electric power to at least one of the processing unit and the multimedia device.  
      The processing unit may include a virtualizer unit to provide a sound field effect to the digital audio signal received from the multimedia device and to output the digital audio signal having the sound field effect, a dynamic range controller unit to receive the digital audio signal having the sound field effect output from the virtualizer, to control a dynamic range of the digital audio signal having the sound field effect to prevent the signal from clipping, and to output a digital output signal, and a digital amplifier unit to receive the digital output signal output from the dynamic range controller, and to output a demodulated audio analog signal to the at least one speaker.  
      The digital amplifier unit may convert the digital output signal received from the dynamic range controller into a pulse width modulation signal, may amplify the pulse width modulation signal to generate an audio analog signal, may demodulate the audio analog signal, and may output the demodulated audio analog signal to the at least one speaker.  
      The digital amplifier unit may include a converter to convert the received digital output signal into the pulse width modulation signal and to output the pulse width modulation signal, a switching unit to receive the pulse width modulation signal output from the converter, to amplify the pulse width modulation signal to generate the audio analog signal, and to output the audio analog signal, and a filter to receive the audio analog signal output from the switching unit, to demodulate the audio analog signal, and to output the demodulated audio analog signal to the at least one speaker.  
      The digital output signal output from the dynamic range controller may include a pulse code modulation signal having a low amplitude. The digital amplifier unit may include an integrated circuit chip. The switching unit may include a field effect transistor. The battery unit may provide power to the switching unit.  
      The portable speaker unit may further include at least one connecting unit to transmit the digital audio signal from the multimedia device to the portable speaker unit. The connecting unit may include at least one of a connecting jack and a connecting dock. The portable speaker unit may further include at least one connecting unit to supply the electric power from the portable speaker unit to the multimedia device. The connecting unit may include negative and positive poles and a ground unit to supply the electric power from the portable speaker unit to the multimedia device. The portable speaker unit may further include a multi-channel interface unit to transmit the digital audio signal from the multimedia device to the portable speaker unit and to supply the electric power from the portable speaker unit to the multimedia device. The multi-channel interface unit may include a signal transmission pin to transmit the digital audio signal from the multimedia device to the portable speaker unit, and a power transmission pin to supply the electric power from the portable speaker unit to the multimedia device.  
      The foregoing and/or other aspects and utilities of the present general inventive concept may also be achieved by providing a portable multimedia apparatus, including a multimedia unit including a signal generating unit to decode audio data and to output a digital audio signal corresponding to the decoded audio data and an internal battery to provide electric power to the signal generating unit, and a removable portable speaker unit including a processing unit to process the digital audio signal output from the signal generating unit and to output an audio analog signal corresponding to the digital audio signal, at least one speaker to receive the audio analog signal output from the processing unit and to output sound corresponding to the audio analog signal, and a battery unit to supply electric power to at least one of the processing unit and the signal generating unit.  
      The portable multimedia apparatus may further include a multi-channel interface unit to transmit the digital audio signal from the signal generating unit to the processing unit and to supply the electric power from the battery unit to the signal generating unit.  
      The foregoing and/or other aspects and utilities of the present general inventive concept may also be achieved by providing a portable multimedia apparatus, including a multimedia device including a signal generating unit to decode audio data and to output a digital audio signal corresponding to the decoded audio data and an internal battery to supply electric power to the signal generating unit, and an external battery pack to supply electric power to the portable multimedia device including at least one speaker to output sound corresponding to the digital analog signal output from the signal generating unit and a battery unit to supply electric power to the signal generating unit of the portable multimedia device.  
      The internal battery may supply the electric power to the signal generating unit until the internal battery is discharged, and then the battery unit may supply the electric power to the portable multimedia device thereafter. The portable multimedia apparatus may further include a multi-channel interface unit to transmit the digital audio signal from the portable multimedia device to the external battery pack and to supply the electric power from the external battery pack to the portable multimedia device. The external battery pack may recharge the internal battery by transmitting electric power thereto.  
      The foregoing and/or other aspects and utilities of the present general inventive concept may also be achieved by providing a method of providing electric power to a portable multimedia device, including supplying the electric power to the portable multimedia device from an internal battery thereof while the internal battery contains a charge, and supplying the electric power to the portable multimedia device from a portable external speaker based on the charge remaining in the internal battery. The method may further include recharging the internal battery of the portable multimedia device by providing electric power from the portable external speaker. The method may further include supplying the electric power to the portable multimedia device from a portable external speaker while maintaining a charge of an internal battery of the portable multimedia device. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      These and/or other aspects and advantages of the present general inventive concept will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:  
       FIG. 1A  is a view illustrating an audio signal output through a built-in speaker of a conventional portable multimedia device;  
       FIG. 1B  is a view illustrating the audio signal output through an earphone connected to the conventional portable multimedia device of  FIG. 1A ;  
       FIG. 2  is a view illustrating a portable multimedia device that is associated with a portable speaker, according to an embodiment of the present general inventive concept;  
       FIG. 3  is a block diagram illustrating the portable speaker of  FIG. 2 , according to an embodiment of the present general inventive concept; and  
       FIG. 4  is a schematic view illustrating a docking jack of the portable speaker illustrated in  FIG. 3 , according to an embodiment of the present general inventive concept. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Reference will now be made in detail to the embodiments of the present general inventive concept, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present general inventive concept by referring to the figures.  
       FIG. 2  is a view illustrating a portable multimedia device that is associated with a portable speaker, according to an embodiment of the present general inventive concept.  
      Referring to  FIG. 2 , a portable speaker  200  is connected to a portable multimedia device  100 .  
      When the portable multimedia device  100  transmits left and right audio signals to the portable speaker  200  through a connector, such as a stereo jack, the portable speaker  200  digitally processes and outputs the left and right sound signals. The portable speaker  200  employs a high performance/high output digital amplifier to improve a sound quality as compared with a conventional built-in speaker of a conventional portable multimedia device (such as the built-in speaker  110  of the portable multimedia device  100  illustrated in  FIG. 1 ).  
      The portable speaker  200  is designed to accommodate a battery therein to function as an external battery pack to supply electric power to the portable multimedia device  100 , such as when an internal battery of the portable multimedia device  100  is fully discharged.  
      The portable speaker  200  may be connected to the portable multimedia device  100  through a variety of connectors, such as a stereo jack, a universal jack, or a dedicated dock to transmit the audio signals from the portable speaker  200  to the portable multimedia device  100 .  
      A connector having negative and positive poles and a ground may be used to supply the electric power from the speaker  200  to the portable multimedia device  200 .  
       FIG. 3  is a view illustrating the portable speaker  200  of  FIG. 2 , according to an embodiment of the present general inventive concept.  
      Referring to  FIG. 3 , the portable speaker  200  may include a two-channel virtualizer  210 , a dynamic range controller (DRC)  220 , a digital amplifier  230 , a battery  240 , and speaker units  250  and  251 .  
      The two-channel virtualizer  210  receives a digital audio signal from the portable multimedia device  100 , provides a sound field effect to the received digital audio signal, and outputs the digital audio signal provided with the sound field effect to the DRC  220 .  
      The DRC  220  controls a dynamic range of the digital audio signal to prevent the signal from clipping in the digital amplifier  230  when the digital audio signal output from the two-channel virtualizer  210  is too high. The DRC  220  also outputs an output signal to the digital amplifier  230 .  
      The digital amplifier  230  may include a pulse width modulation (PWM) converter  231 , a switching unit  232 , and a low-band path filter  233 .  
      The digital amplifier  230  converts a digital input signal, such as a pulse code modulation (PCM) signal having a low amplitude, into a PWM signal, amplifies the PWM signal using an amplifying circuit having a semiconductor switching element  232 , such as a field effect transistor (FET), and outputs an audio analog signal demodulated by the low-band path filter  233  to the speaker units  250  and  251 . The operations of the digital amplifier  230  will be now described in more detail.  
      The PWM converter  231  converts the digital signal transmitted from the DRC  220  into the PWM signal and outputs the PWM signal to the switching unit  232 .  
      The switching unit  232  amplifies the PWM signal by receiving electric power from the battery  240  and outputs the amplified PWM signal to the low-band path filter  233 .  
      The low-band path filter  233  demodulates the amplified PWM signal received from the switching unit  232  into the audio analog signal and outputs the audio analog signal to the speaker units  250  and  251 .  
      The speaker units  250  and  251  receive the analog signal from the low-band path filter to generate sound.  
      The digital amplifier  230  may be formed of, for example, an integrated circuit (IC) chip to reduce a size of the portable speaker.  
      The battery  240  supplies the electric power to the digital amplifier  230  as well as to the portable multimedia device  100 . As the battery  240  can be installed in the portable speaker  200 , the portable speaker  200  can function as an external battery pack to supply the electric power to the portable multimedia device  100  when an internal battery  140  of the portable multimedia device  100  is fully discharged.  
      In order to supply electric power from the portable speaker  200  to the portable multimedia device  100 , a connector having a Vcc and ground GND may be used.  
      The portable speaker  200  may also include a mute function. The mute function may be turned on or off by a mute switch (not illustrated). In addition, a two-channel virtualizer function may be turned on or off by a switch.  
      Although  FIG. 3  is a view illustrating a case where the electric power is always supplied from the portable speaker  200  to the portable multimedia device  100  (as opposed to an electric power being supplied from the internal battery  140  to the portable multimedia device  100 ), the electric power may be supplied from the portable speaker  200  to the multimedia device  100  only when the internal battery  140  of the portable multimedia device  100  is fully discharged. In other words, the electric power may be initially supplied by the portable speaker  200 , even when the internal battery  140  of the portable multimedia device  100  is not fully discharged. Alternatively, the electric power may be initially supplied by the internal battery  140  of the portable multimedia device  100 , and subsequently supplied by the portable speaker  200  when the internal battery  140  of the portable multimedia device  100  is fully discharged.  
      The portable multimedia device  100  may include an MP3 decoding/digital audio signal generating unit  130  as well as the internal battery  140 . The MP3 decoding/digital audio signal playing unit  130  decodes MP3 data and plays the digital audio signal. The internal battery  140  supplies the electric power to the MP3 decoding/digital audio signal playing unit  130 . The internal battery  140  is recharged by receiving recharging power transmitted from the portable speaker/battery charging unit  200 .  
      When the portable multimedia device outputs  2 -N digital audio signals, such as left and right signals or 5.1-channel signals, the portable speaker  200  receives the digital audio signals and outputs the sound through the speaker units  250  and  251 . Since the portable speaker  200  employs the digital amplifier  230  having a high performance/high output and a size smaller than a typical analog amplifier, sound quality and output can be improved as compared with the conventional built-in speaker  110  of the portable multimedia device  100  of  FIG. 1 .  
       FIG. 4  is a view illustrating a docking jack  300  to connect the portable speaker  200  to the portable multimedia device  100 .  
      Referring to  FIG. 4 , the docking jack  300  functions as a multi-channel interface that transmits the digital audio signal from the portable multimedia device  100  to the portable speaker  200  through a signal data transmission pin  320  and supplies the electric power from the battery  240  loaded in the portable speaker  200  to the portable multimedia device  100  through a power transmission pin  310  (e.g., to recharge the internal battery  140  of the portable multimedia device  100 ).  
      According to embodiments of the present general inventive concept, since a user listens to an audio signal that is not output from an earphone or a built-in speaker of a portable multimedia device, but from a portable speaker employing a high performance/high output digital amplifier, the user can enjoy a high quality sound.  
      Also, the user can carry the portable speaker employing a virtual technology, such as a virtual speaker/stereo dipole, and use the portable speaker by associating the same with the portable multimedia device.  
      Furthermore, when an internal battery of the portable multimedia device is fully discharged at a place where the internal battery cannot be recharged, electric power can be supplied from a battery loaded in the portable speaker to the portable multimedia device.  
      Also, since the portable speaker may include a DRC, clipping of the audio signal can be prevented.  
      Although a few embodiments of the present general inventive concept have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the appended claims and their equivalents.