Patent Publication Number: US-2011058694-A1

Title: Audio Signal Switching Apparatus

Description:
CROSS-REFERENCE 
     This application is a continuation of application Ser. No. 11/341,102, filed Jan. 27, 2006, which claims priority to Taiwan Application Serial Number 94103426, filed Feb. 3, 2005. The entire disclosures of all the above applications are hereby incorporated by reference herein. 
    
    
     BACKGROUND 
     1. Field of Invention 
     The present invention relates to an audio signal switching apparatus. More particularly, the present invention relates to a circuit for switching an audio output path of a computer system. 
     2. Description of Related Art 
     With the rapid development of information technology, computers and peripherals have become very popular. A modern design is to configure I/O ports which users often use onto a front panel of a computer case, such that users may conveniently and freely plug in their peripherals, such as earphones or USB drives. In this modern case design, an audio output of the computer system (e.g. an audio codec) is generally confined to output audio signals only to an audio jack on the front panel or a speaker jack on the rear panel of the computer system. That is, the user can only select to use either an earphone or a speaker to play the music media stored in the computer system. When the user is listening to the audio signals through the audio jack of the front panel (e.g. by plugging in the earphone), the speaker plugged into the speaker jack of the rear panel does not receive the audio signals. 
     Moreover, digital audio playing devices are widely used recently, and portable digital audio players, such as CD walkmans or MP3 walkmans, are especially popular with the general public. If used to play digital audio media, the computer system must be turned on to decode and output the digital audio media. Some computer manufacturers provide a computer architecture called “barebone”, which is similar to a household appliance. The barebone can play the digital audio media while the computer is turned off, thus enabling users to listen to music by the barebone without turning the computer system on, i.e. without loading the operating system of the computer. 
     However, the barebone has many disadvantages. The barebone is expensive because the customer has to pay at least 50 USD for an operation interface and a simple digital audio playing system (e.g. a system chip, NAND Flash and DRAM) on the computer. Moreover, the simple digital audio playing system cannot offer various sound effects and enhancements or a full management of songs. The operation interface of the simple digital audio playing system is generally different from that of the walkman which the user is accustomed to, so the user may confuse using the two different operation interfaces. In addition, some special digital audio media for walkmans (like iPod) have specific access protections, making them hard to play directly by the barebone. 
     SUMMARY 
     The present invention provides an audio signal switching apparatus, which enables users to directly connect a digital audio playing device and a speaker through a computer system, so as to decrease the cost and obtain a good audio signal processing ability. 
     According to the present invention, the audio signal switching apparatus at least comprises an audio jack, a speaker jack, a detection circuit and a control circuit. The audio jack and the speaker jack are separately configured in a computer system. The detection circuit detects whether the computer system is turned on or turned off. The control circuit is electrically connected to the detection circuit and connects the audio jack and the speaker jack when the computer system is turned off. 
     It is another aspect of the present invention to provide an audio signal switching apparatus, which can automatically or manually switch an audio output path of a computer system, in order to increase the computer system value and enhance the operating convenience of users. 
     According to the present invention, the audio signal switching apparatus at least comprises a case and a control circuit. The case at least comprises a computer system and has an audio jack and a speaker jack. The control circuit is electrically connected to the audio jack, the speaker jack and the computer system. When the computer system is turned off, the control circuit is arranged to electrically connect the audio jack to the speaker jack. 
     It is still another aspect of the present invention to provide a computer system, which connects its original audio jack and speaker jack when turned off, such that users can directly plug in an audio playing device to play audio media. 
     According to the present invention, the computer system has an audio jack and a speaker jack, and can selectively output audio signals through the audio jack or the speaker jack when turned on. The computer system is characterized by comprising an audio signal switching apparatus, which electrically connects the audio jack to the speaker jack when the computer system is turned off. 
     It is to be understood that both the foregoing general description and the following detailed description are examples, and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features, aspects and advantages of the present invention will become better understood with regard to the following description, appended claims and accompanying drawings where: 
         FIG. 1A  is a front view of one preferred embodiment of the present invention; 
         FIG. 1B  is a rear view of the preferred embodiment; 
         FIG. 2  is a circuit functional block diagram of one preferred embodiment of the present invention; 
         FIG. 3  is a circuit functional block diagram of another preferred embodiment of the present invention; and 
         FIG. 4  is a circuit functional block diagram of another preferred embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. 
     The present invention electrically connects an audio jack to a speaker jack when a computer system is turned off, and thus a user can play the audio media of an external audio playing device directly by a speaker coupled to the computer system. Therefore, the user can operate the same operation interface that he is used to whether he is listening to the audio media by an earphone coupled to a walkman or by the speaker coupled to the computer system. 
       FIG. 1A  is a front view of one preferred embodiment of the present invention, and  FIG. 1B  is a rear view of the preferred embodiment, illustrating configurations of an audio jack and a speaker jack in a computer system. In the preferred embodiment, a computer system  100  is a host computer system or a barebone computer system. A case  102  of the computer system  100  has a front panel  112  and a rear panel  122 . The audio jacks which users often use, such as an earphone output jack  114  or a microphone output jack  116 , are configured on the front panel  112  for users to plug in their peripherals, such as an earphone or a microphone. The speaker jack  124  used to connect a speaker is generally configured on the rear panel  122  for users to easily arrange and hide the connecting cables of the speaker behind the computer system  100 . 
       FIG. 2  is a circuit functional block diagram of one preferred embodiment of the present invention. An audio signal switching apparatus  200  is used in the computer system  100  as illustrated in  FIG. 1A  and  FIG. 1B  and at least comprises an audio jack  202 , a speaker jack  204 , a detection circuit  206  and a control circuit  208 . The audio jack  202  and the speaker jack  204  are separately configured in the computer system  100 . The detection circuit  206  detects whether the computer system  100  is turned on (“ON”) or turned off (“OFF”). The control circuit  208  is electrically connected to the detection circuit  206  and connects the audio jack  202  and the speaker jack  204  when the computer system  100  is turned off. 
     When the computer system  100  is turned on, the control circuit  208  is arranged to selectively connect one of the audio jack  202  or the speaker jack  204  to an audio codec  212  of the computer system  100 . In other words, at that time, the user can only select either the audio jack  202  or the speaker jack  204  to play the music media from the computer system  100 . When the user is listening to the audio signals of the computer system  100  by the audio jack  202  (e.g. with the earphone or another speaker), the speaker connected to the speaker jack  204  does not receive the same audio signals. Conversely, when the user is listening to the audio signals of the computer system  100  by the speaker jack  204 , the peripherals connected to the audio jack  202  do not receive the same audio signals. 
     In the preferred embodiment, the detection circuit  206  and the control circuit  208  are integrated into a motherboard  222  of the computer system  100 . The audio codec  212  can be a built-in audio chip of the motherboard  222  or an external audio card plugged into the motherboard  222 . The detection circuit  206  determines whether the computer system  100  is turned on or turned off according to an electrical signal of the motherboard  222 , such as a +5V signal or other power-up or power-down signals or flags. The audio jack  202  can be the earphone output jack  114  or the microphone input jack  116 , which is for example configured on the front panel  112  of the case  102  of the computer system  100 , enabling input of audio media from another audio playing device, such as a CD walkman or an MP3 walkman. The speaker jack  204  is, for example, configured on the rear panel  122  of the case  102  of the computer system  100 , for connecting a speaker, an amplifier or other audio output apparatus. 
     In addition, the audio signal switching apparatus  200  further comprises an operation interface  214 , such as a liquid crystal panel and a set of buttons electrically connected to the control circuit  208 . By this operation interface  214 , user can manually switch the audio jack  202  to be electrically connected to the speaker  204  or the audio codec  212 . 
       FIG. 3  is a circuit functional block diagram of another preferred embodiment of the present invention. An audio signal switching apparatus  300  at least comprises a case  306  and a control circuit  308 . The case  306  physically encloses a motherboard (not illustrated) and comprises an audio jack  302  and a speaker jack  304 . The control circuit  308  is electrically connected to the audio jack  302 , the speaker jack  304  and the motherboard. The control circuit  308  can be configured on the motherboard, and when the motherboard is turned off (“OFF”), the control circuit  308  electrically connects the audio jack  302  to the speaker jack  304 . Moreover, when the motherboard is turned on (“ON”), the control circuit  308  is arranged to selectively connect one of the audio jack  302  or the speaker jack  304  to an audio codec  312 . 
     In the preferred embodiment, the control circuit  308  has both functions of detecting whether the computer is turned on or turned off and switching the audio output path. The control circuit  308  determines whether the motherboard is turned on or turned off according to an electrical signal of the motherboard, such as a +5V signal or other power-up or power-down signals or flags. The audio jack  302  can be an earphone output jack or a microphone input jack, which is for example configured on the front panel of the case  306 , enabling input of audio media from another audio playing device, such as a CD walkman or an MP3 walkman. The speaker jack  304  is for example configured on the rear panel of the case  306 , for connecting a speaker, an amplifier or other audio output apparatus. The audio codec  312  can be a built-in audio chip of the motherboard or an external audio card plugged into the motherboard. 
     In addition, the audio signal switching apparatus  300  further comprises an operation interface  314 , such as a liquid crystal panel and a set of buttons, electrically connected to the control circuit  308 . By this operation interface  314 , user can manually switch the audio jack  302  to be electrically connected to the speaker  304  or to the audio codec  312 . 
       FIG. 4  is a circuit functional block diagram of another preferred embodiment of the present invention. An audio signal switching apparatus  400  has an audio jack  402 , a speaker jack  404  and a control circuit  408 . The control circuit  408  is electrically connected to the audio jack  402  and the speaker jack  404 . When a computer system (e.g. containing a motherboard) is turned off (“OFF”), the control circuit  408  electrically connects the audio jack  402  to the speaker jack  404 . When the computer system is turned on (“ON”), the control circuit  408  is arranged to selectively connect one of the audio jack  402  and the speaker jack  404  to an audio codec  412 . 
     In the preferred embodiment, the control circuit  408  has both functions of detecting whether the computer is turned on or turned off and switching the audio output path. The control circuit  408  is integrated into the audio codec  412 . The audio codec  412  can be a built-in audio chip of the motherboard or an external audio card plugged into the motherboard. Persons skilled in the art can understand that the control circuit for switching the audio output path and the detection circuit for detecting whether the computer is turned on or turned off are two independent circuits with different functions; two different functions also can be integrated into the audio codec  412 , thus decreasing the cost and the occupied space. 
     Moreover, the control circuit  408  determines whether the computer system is turned on or turned off according to an electrical signal of the computer system, such as a +5V signal of the motherboard or other power-up or power-down signals or flags. The audio jack  402  can be an earphone output jack or a microphone input jack, which is for example configured on the front panel of the case of the computer system, enabling input of audio media from another audio playing device, such as a CD walkman or an MP3 walkman. The speaker jack  404  is, for example configured on the rear panel of the case of the computer system, for connecting a speaker, an amplifier or other audio output apparatus. 
     In addition, the audio signal switching apparatus  400  further comprises an operation interface  414 , such as a liquid crystal panel and a set of buttons, electrically connected to the control circuit  408 . By this operation interface  414 , user can manually switch the audio jack  402  to be electrically connected to the speaker  404  or to the audio codec  412 . 
     The audio signal switching apparatus of these foregoing embodiments can allow a user to directly connect his audio signal playing device through the audio jack to the speaker which is connected to the speaker jack of the computer system and to output the audio media of the audio signal playing device to the speaker. Listening to audio media in this manner without turning on the computer can prevent wasting power and noise interference by the computer fans. The simple digital audio playing system of the computer system, which is very expensive but has low functionality, can be omitted. Additionally, the user only needs to know one operation interface well and never has to consider the specific protections of accessing or converting audio media among different system platforms. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.