Abstract:
An electronic device includes a processing unit for outputting a right channel audio signal and a left channel audio signal, and an interface circuit for generating a processed right channel audio signal and a processed left channel audio signal accordingly. The interface circuit includes two output units for electrically connecting two plugs of two speakers respectively. Each output unit includes a first pin, a second pin, and an anti-jam member. When a plug is inserted into the output unit, the first pin transmits the processed right channel audio signal to the plug, the second pin transmits the processed left channel audio signal to the plug, and the anti jam member is in an open state. When the plug is dependent from the output unit, the first pin is in series with the second pin by the anti jam member.

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to electronic devices, and particularly to an electronic device with an interface circuit. 
     2. Description of Related Art 
     Electronic devices, such as DVD players, usually include an interface circuit for peripherals. The interface circuit for a DVD player may includes two output units for respectively transmitting right channel audio signals and left channel audio signals to two speakers. When one output unit connects with one speaker and the other output unit does not connect with the other speaker a signal cross-disturbance exits between the two output units, thus one of the right channel audio signals or the left channel audio signals output by the unit unconnected with the speaker will disturb the other channels output. 
     Therefore, there is room for improvement in the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The components of the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the embodiment of an electronic device with a mute control circuit. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the views. 
         FIG. 1  is a functional block diagram of an electronic device including an interface circuit according to an exemplary embodiment. 
         FIG. 2  is a detailed circuit diagram of the interface circuit of  FIG. 1  in an initial state. 
         FIG. 3  is a detailed circuit diagram of the interface circuit of  FIG. 1  in a working state. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present disclosure will now be described in detail with reference to the drawings. 
     Referring to  FIG. 1 , an electronic device  100  according to an exemplary embodiment is illustrated. In this embodiment, the electronic device  100  is a DVD player. The electronic device  100  includes a processing unit  10 , an interface circuit  30 , and two speakers  40 . 
     The processing unit  10  is used for generating audio signals including a right channel audio signal and a left channel audio signal. The processing unit  10  includes a first output port  11  and a second output port  13 . The first output port  11  is used to output the left channel audio signal. The second output port  13  is used to output the right channel audio signal. 
     The interface circuit  30  is electrically connected to the processing unit  10 . The interface circuit  30  is used for transmitting the right channel audio signal and the left channel audio signal to the two speakers  40  when the two speakers  40  are electrically connected to the interface circuit  30 . The two speakers  40  emit sounds according to the right channel audio signal and the left channel audio signal. Each speaker  40  includes a plug  41  for electrically connecting to the interface circuit  30 . Each plug  41  includes a first input port  410  and a second input port  412 . 
     The interface circuit  30  includes a first output unit  21 , a second output unit  23 , a first sub-circuit  31 , a second sub-circuit  33 , a third sub-circuit  35 , and a fourth sub-circuit  37 . 
     The first sub-circuit  31  and the third sub-circuit  35  are the same and are both used for processing the right channel audio signal from the second output port  13 , and for generating a processed right channel audio signal. 
     The second sub-circuit  33  and the fourth sub-circuit  37  are the same and are both used for processing the left channel audio signal from the first output port  11 , and for generating a processed left channel audio signal. 
     The first output unit  21  and the second output unit  21  are the same. The first output unit  21  is used for receiving the processed right channel audio signal from the first sub-circuit  31  and the processed left channel audio signal from the second sub-circuit  33 . It is further used for transmitting the processed right channel audio signal and the processed left channel audio signal to the speaker  40 , which is electrically connected to the first output unit  21 . 
     The first output unit  21  includes a first pin  213 , a second pin  214 , a third pin  211 , a fourth pin  212 , a fifth pin  215 , and a first anti jam member  216 . The third pin  211  is electrically grounded. The fourth pin  212  is electrically connected to the second output port  13  by the first sub-circuit  31 . The first pin  213  is detachably and is electrically connected to the fourth pin  212 . The first pin  213  is further electrically connected to the second pin  214  by the first anti-jam member  216 . The second pin  214  is detachably and is electrically connected to the fifth pin  215 . The fifth pin  215  is further electrically connected to the first output port  11  by the second sub-circuit  33 . 
     When the speaker  40  is connected to the first output unit  21 , the first pin  213  is detached from the fourth pin  212 , and the second pin  214  is detached from the fifth pin  215 . The first anti-jam member  216  is in an open circuit. The fourth pin  212  is electrically connected to the second input port  412  to transfer the processed right channel audio signal. The fifth pin  215  is electrically connected to the first input port  410  to transfer the processed left channel audio signal. Thus, the first anti jam member  216  does not affect the first output unit  21  to transmit the processed right channel audio signal and the processed left channel audio signal to the speaker  40 . 
     When the speaker  40  is independent from the first output unit  21 , the first pin  213  is electrically connected to the fourth pin  212 , and the second pin  214  is electrically connected to the fifth pin  215 . The first anti jam member  216  is in series with the fourth pin  212  and the fifth pin  215 . Thus, the first anti jam member  216  attenuates the processed right channel audio signal and the processed left channel audio signal. 
     The second output unit  23  is used for receiving the processed right channel audio signal from the third sub-circuit  35  and the processed left channel audio signal from the fourth sub-circuit  37 . The second output unit  23  is further used for transmitting the processed right channel audio signal and the processed left channel audio signal to one of the speakers  40 , which is electrically connected to the first output unit  21 . 
     The second output unit  23  includes a sixth pin  233 , a seventh pin  234 , an eighth pin  231 , a ninth pin  232 , a tenth pin  235 , and a second anti jam member  236 . The eighth pin  231  is electrically grounded. The ninth pin  232  is electrically connected to the second output port  13  by the third sub-circuit  35 . The ninth pin  232  is further detachably and is electrically connected to the sixth pin  233 . The sixth pin  233  is electrically connected to the seventh pin  234  by the second anti jam member  236 . The seventh pin  234  is detachably and is electrically connected to the tenth pin  235 . The tenth pin  235  is further electrically connected to the first output port  11  by the fourth sub-circuit  37 . 
     When the speaker  40  is connected to the second output unit  23 , the ninth pin  232  is detached from the sixth pin  233 , and the tenth pin  235  is detached from the seventh pin  234 . The second anti-jam member  236  is in an open circuit. The ninth pin  232  is electrically connected to the second input port  412  to transfer the processed right channel audio signal. The tenth pin  235  is electrically connected to the first input port  410  to transfer the processed left channel audio signal. Thus, the second anti jam member  236  does not affect the second output unit  23  to transmit the processed right channel audio signal and the processed left channel audio signal to the speaker  40 . 
     When the speaker  40  is independent from the second output unit  23 , the ninth pin  232  is electrically connected to the sixth pin  233 , and the tenth pin  235  is electrically connected to the seventh pin  234 . The second anti jam member  236  is connected in series with the ninth pin  232  and the tenth pin  235 . Thus, the second anti jam member  236  attenuates the processed right channel audio signal and the processed left channel audio signal. 
     Referring to  FIG. 1  again, when the first output unit  21  electrically connects with the speaker  40 , and the second output unit  23  is independent from the speaker  40 . A loop circuit will be formed by the second output port  13 , the third sub-circuit  35 , the ninth pin  232 , the sixth pin  233 , the second anti jam member  236 , the seventh pin  234 , the tenth pin  235 , the fourth sub-circuit  37 , the second sub-circuit  33 , the fifth pin  215 , the second pin  214 , and the first input port  410 . Thus, the processed right channel audio signal will reach the first input port  410  through the loop circuit. The processed left channel audio signal of the first input port  410  is disturbed. However, as the second anti jam member  236  is in series with the loop circuit, it attenuates the processed right channel audio signal. After being attenuated, the processed right channel audio signal can not affect the processed left channel audio signal of the first input port  410 . 
     For the same reason, the processed left channel audio signal cannot affect the processed right channel audio signal of the second input port  412 . When the second output unit  23  is connected to the speaker  40 , and the first output unit  21  is independent from the speaker  40 . The processed right channel audio signal cannot affect the processed left channel audio signal of the first input port  410 , and the processed left channel audio signal cannot affect the processed right channel audio signal of the second input port  412 . 
     Further referring to  FIG. 2 , in this embodiment, the first anti jam member  216  is a first resistor R 1 , and the second anti jam member  236  is a second resistor R 2 . 
     The first sub-circuit  31  is used for transmitting the right channel signal from the second output port  13  to the fourth pin  212  of the first output unit  21 . The first sub-circuit  31  includes a third resistor R 3 , a fourth resistor R 4 , a first inductor L 1 , and a first capacitor C 1 . One end of the third resistor R 3  is electrically connected to the second output port  13 , and the other end of the third resistor R 3  is electrically connected to the fourth pin  212  by the first inductor L 1 . One end of the fourth resistor R 4  is electrically connected between the third resistor R 3  and the first inductor L 1 , and the other end of the fourth resistor R 4  is electrically grounded. One end of the first capacitor C 1  is electrically connected to the fourth pin  212 , and the other end of the first capacitor C 1  is electrically grounded. The third resistor R 3 , the first inductor L 1 , and the first capacitor C 1  define a RLC filtering circuit for filtering signals. The fourth resistor R 4  is a pull down voltage resistor. 
     The second sub-circuit  33  is used for transmitting the left channel signal from the first output port  11  to the second pin  214  of the first output unit  21 . The second sub-circuit  33  includes a fifth resistor R 5 , a sixth resistor R 6 , a second inductor L 2 , and a second capacitor C 2 . One end of the fifth resistor R 5  is electrically connected to the first output port  11 , and the other end of the fifth resistor R 5  is electrically connected to the fifth pin  215  by the second inductor L 2 . One end of the sixth resistor R 6  is electrically connected between the fifth resistor R 5  and the second inductor L 2 , and the other end of the sixth resistor R 6  is electrically grounded. One end of the second capacitor C 2  is electrically connected to the fifth pin  215 , and the other end of the second capacitor C 2  is electrically grounded. The fifth resistor R 5 , the second inductor L 2 , and the second capacitor C 2  define a RLC filtering circuit for filtering signals. The sixth resistor R 6  is a pull down voltage resistor. 
     The third sub-circuit  35  is used for transmitting the right channel signal from the second output port  13  to the sixth pin  233  of the second output unit  23 . The third sub-circuit  35  includes a seventh resistor R 7 , an eighth resistor R 8 , a third inductor L 3 , and a third capacitor C 3 . One end of the seventh resistor R 7  is electrically connected to the second output port  13 , and the other end of the seventh resistor R 7  is electrically connected to the ninth pin  232  by the third inductor L 3 . One end of the eighth resistor R 8  is electrically connected between the seventh resistor R 7  and the third inductor L 3 , and the other end of the eighth resistor R 8  is electrically grounded. One end of the third capacitor C 3  is electrically connected to the ninth pin  232 , and the other end of the third capacitor C 3  is electrically grounded. The seventh resistor R 6 , the third inductor L 3 , and the third capacitor C 3  define a RLC filtering circuit for filtering signals. The eighth resistor R 8  is a pull down voltage resistor. 
     The fourth sub-circuit  37  is used for transmitting the left channel signal from the first output port  11  to the seventh pin  234  of the second output unit  23 . The fourth sub-circuit  33  includes a ninth resistor R 9 , a tenth resistor R 10 , a fourth inductor L 4 , and a fourth capacitor C 4 . One end of the ninth resistor R 9  is electrically connected to the first output port  11 , and the other end of the ninth resistor R 9  is electrically connected to the tenth pin  235  by the fourth inductor L 4 . One end of the tenth resistor R 10  is electrically connected between the ninth resistor R 9  and the fourth inductor L 4 , and the other end of the tenth resistor R 10  is electrically grounded. One end of the fourth capacitor C 4  is electrically connected to the tenth pin  235 , and the other end of the fourth capacitor C 4  is electrically grounded. The ninth resistor R 9 , the fourth inductor L 4 , and the fourth capacitor C 4  define a RLC filtering circuit for filtering signals. The tenth resistor R 10  is a pull down voltage resistor. 
     The third resistor R 3 , the fifth resistor R 5 , the seventh resistor R 7 , and the ninth resistor R 9  have the same resistance. Each resistance of the first resistor R 1  and the second resistor R 2  is far greater than that of the third resistor R 3 . In this embodiment, each resistance of the first resistor R 1  and the second resistor R 2  is about 3 to 10 times the third resistor R 3 . 
     Further referring to  FIG. 3 , when the first output unit  21  is connected to the speaker  40 , and the second output unit  23  is independent from the speaker  40 , the first anti jam member  216  is in an open circuit, and the second anti jam member  236  is in series with the ninth pin  232  and the tenth pin  215 . The fourth pin  212  is electrically connected to the second input port  412 . The fifth pin  215  is electrically connected to the first input port  410 . As the second resistor R 2  has a great resistance, the second resistor R 2  attenuates the processed right channel audio signal to the first input port  410  or attenuates the processed left channel audio signal to the second input port  412 . 
     As discussed above, when only one speaker  40  is connected to one of the first output units  21  and the second output unit  23  of the electronic device  100 , the first output unit  21  and the second output unit  23  connected to the speaker  40  will not be affected by the other first output unit  21  and the second output unit  23 . Cross talk between the processed left channel audio signal and the processed right channel audio signal is reduced. 
     While various exemplary and preferred embodiments have been described, it is to be understood that the disclosure is not limited thereto. To the contrary, various modifications and similar arrangements (as would be apparent to those skilled in the art) are intended to also be covered. Therefore, the scope of the appended claims should be accorded the broadest interpretation to encompass all such modifications and similar arrangements.