Patent Translate Powered by EPO and Google Notice This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate, complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or financial decisions, should not be based on machine-translation output. DESCRIPTION JP2008283581 PROBLEM TO BE SOLVED: In a multi-channel amplifier having amplification means for headphones, when headphones are not used, the audio signal path to the front speaker is not adversely affected by the audio signal path to the headphone, and the sound output from the front speaker is high. Provided is a multi-channel amplifier that realizes low-cost implementation of sound quality. SOLUTION: A multi-channel amplifier according to the present invention has a buffer circuit from a first input terminal 1 for outputting a front channel signal FL / FR to a front speaker when headphones are not connected to an output terminal for headphones. The audio signal path from the switch IC 9 to the first volume adjustment means 3a, the buffer circuit 10b and the first amplification means 4a to the front speaker output terminal 6 is not electrically connected to other audio signal paths The switch IC and the first to third switches are on / off controlled by the control means 5 so that [Selected figure] Figure 1 Multichannel amplifier [0001] The present invention relates to a multichannel amplifier comprising amplifier means for headphones. [0002] A conventional multichannel amplifier will be described. 10-05-2019 1 FIG. 3 is a circuit diagram showing a schematic configuration of a conventional multi-channel amplifier. The conventional multi-channel amplifier includes a front channel volume adjustment unit 3a, a surround channel volume adjustment unit 3b, a front channel amplification unit 4a, a surround channel amplification unit 4b, a headphone amplification unit 4c, and a control unit. And 5, a front speaker output terminal 6, a surround speaker output terminal 7, a headphone output terminal 8, and switches SW1 to SW3. [0003] The front channel volume adjustment means 3a receives the front channel signal FL / FR, which is an analog audio signal input via the input terminal 1, adjusts the level of the front channel signal FL / FR, and amplifies the front channel Output to means 4a. The front channel amplification means 4a amplifies the front channel signal FL / FR and outputs it to the front speaker terminal 6 through the switch SW1. Then, the front channel signal FL / FR is output to the front speaker connected to the front speaker output terminal 6 and converted into sound. [0004] The surround channel volume adjustment means 3b receives the analog surround channel signal SL / SR input via the input terminal 2, adjusts the level of the surround channel signal SL / SR, and outputs the surround channel signal SL / SR to the surround channel amplification means 4b. Do. The surround channel amplification means 4b amplifies the surround channel signals SL / SR and outputs the surround channel signals SL / SR to the surround speaker output terminal 7 via the switch SW2. Then, the surround channel signals SL / SR are output to the surround speakers connected to the surround speaker terminal 7 and converted into sounds. [0005] The headphone amplification means 4c has its input end connected in parallel with the front channel amplification means 4a at a stage subsequent to the front volume adjustment means 3a, and the front channel signal FL / FR adjusted in level by the front channel volume adjustment means 3a. Is input. The headphone amplification means 4c amplifies the input front channel signal FL / FR and outputs the amplified front channel signal FL / FR to the headphone output terminal 8 through the switch SW3. Then, the front channel signal FL / FR is output to the headphones connected to the headphone output terminal 8 and converted into sound. 10-05-2019 2 [0006] When the headphones are connected, the headphone output terminal 8 outputs that the headphones and the headphone output terminal 8 are connected to the control means 5 as a connection signal. The control means 5 detects a connection signal output from the headphone output terminal 8 and controls the switches SW1 to SW3 on and off based on the connection signal. [0007] When no headphone is connected to the headphone output terminal 8, the control means 5 performs the switches SW1 and SW2 so that the front channel signal FL / FR or the surround channel signal SL / SR is output to the front speaker or the surround speaker, respectively. On and the switch SW3 off. Further, when headphones are connected to the headphone output terminal 8, the control means 5 turns off the switches SW1 and SW2 and turns on the switch SW3 so that the front channel signal FL / FR is output to the headphones. [0008] In such a conventional multi-channel amplifier, even when the headphone is not connected to the headphone output terminal 8, the headphone amplification means 4c functions as the front channel amplification means after the front channel volume adjustment means 3a. Since it is in a state of being connected in parallel with 4a, the sound quality is deteriorated by the fact that the input impedance of the front channel amplification means 4a drops or the wiring to the headphone amplification means 4c becomes an inductor component. There's a problem. [0009] Therefore, relays are respectively provided in front of the front channel amplifier 4a and the headphone amplifier 4c, and when the headphones are not connected to the headphone output terminal 8, the relays are controlled to turn on and off and the front channel amplifier 4a and the headphones are controlled. There is a method of solving the above-mentioned problem by electrically disconnecting the amplifier 4c. 10-05-2019 3 However, relays are expensive and cost-prone. [0010] Japanese Patent Application Laid-Open No. 10-13987 [0011] The present invention has been made to solve the above-mentioned problems of the prior art, and its object is to provide a multi-channel amplifier having amplification means for headphones, even when headphones are not used. An object of the present invention is to provide a multichannel amplifier that realizes high-quality sound output from a front speaker without the audio signal path to a speaker being adversely affected by the audio signal path to a headphone. [0012] A multi-channel amplifier according to a preferred embodiment of the present invention has a first input terminal to which a front channel signal is input, a second input terminal to which a surround channel signal is input, and the front channel signal. First volume adjustment means for adjusting the level of the channel signal; second volume adjustment means for receiving the front channel signal or the surround channel signal and adjusting the level of the front channel signal or the surround channel signal; Connected to the first volume adjusting means, which is connected to the first volume adjusting means, amplifies the front channel signal supplied from the first volume adjusting means and outputs the amplified signal to the front speaker; Amplifying the surround channel signal supplied from the second volume adjustment means A second amplification means for outputting to a round speaker, and the second volume adjustment means connected in parallel with the second amplification means to amplify the front channel signal supplied from the second volume adjustment means A third amplification means, a headphone output terminal connectable to headphones and outputting the front channel signal supplied from the second amplification means, and the first volume adjustment from the first input end Means and first switch means for switching a first path leading to the front speaker through the first amplification means to the connected state or the disconnected state; and the second volume control means from the first input end A second switch means for switching the second path to the connection state to the connection state or the disconnection state, and a third path from the second input end to the second volume adjustment means the connection state or the disconnection Shape Third switch means for switching to the second sound source, and fourth switch means for switching the fourth path from the second volume adjustment means to the surround speaker via the second amplification means to the connected state or the nonconnected state; A fifth switch means for switching a fifth path from the second volume adjustment means to the headphone output terminal via the third amplification means to the 10-05-2019 4 connection state or the disconnection state; and the headphone is the headphone Control means for controlling switching of the connection state or non-connection state of the first to fifth paths based on whether or not the output terminal is connected to the output terminal; When the headphones are not connected, the first and second switch means are controlled such that the first path is in the connection state and the second path is in the disconnection state. [0013] In a further preferred embodiment, the first switch means includes a switch unit for switching the connection between the first input end and the first volume adjustment means to a connected state or a disconnected state, and for the headphone When the headphone is connected to the output terminal, the first path, the third path, and the fourth path are not connected, and the second path and the fifth path are connected. To control the switch unit and the second to fifth switches. [0014] In a further preferred embodiment, a first or second buffer circuit is connected between the first input end or the second input end and the switch IC, and the switch IC and the first volume adjustment A third or fourth buffer circuit is connected between the means or the second volume adjusting means. [0015] According to the present invention, in a multi-channel amplifier having amplification means for headphones, the audio signal path to the front speakers and the audio to the headphones when the headphones are not used (that is, when sound is output from the front speakers). By disconnecting from the signal path, the audio signal path to the front speaker is not affected by the signal path to the headphone, and a multi-channel amplifier is realized to realize high-quality sound output from the front speaker It is possible to [0016] The following describes a multi-channel amplifier according to preferred embodiments of the present invention, but the present invention is not limited to these embodiments. The same or corresponding parts in the drawings are denoted by the same reference numerals and their descriptions are incorporated. 10-05-2019 5 [0017] First, referring to FIG. 1, the schematic configuration of the multi-channel amplifier of the present invention will be described. FIG. 1 is a circuit diagram showing a multi-channel amplifier according to a preferred embodiment of the present invention. [0018] The multi-channel amplifier includes a first input terminal 1, a second input terminal 2, a first volume control unit 3a, a second volume control unit 3b, a first amplification unit 4a, and a second A surround speaker to which a front speaker output terminal 6 to which an amplification means 4b, a third amplification means 4c, a control means 5, a front speaker (not shown) are connected, and a surround speaker (not shown) are connected And a headphone output terminal 8 to which headphones (not shown) are connected, switches SW1 to SW3, a switch IC 9, and buffer circuits 10a to 10d. [0019] The first input terminal 1 receives the front channel signal FL / FR which is an analog audio signal from the outside, and the second input terminal 2 receives the surround channel signal SL / SR which is the analog audio signal from the outside Be done. [0020] The first volume adjustment means 3a adjusts the level of the front channel signal FL / FR inputted from the first input terminal 1 and outputs the same to the first amplification means 4a. In the present embodiment, the first volume adjustment means 3a includes an operational amplifier OP1, and the output end of the operational amplifier OP1 is connected to the output end of the volume adjustment means 3a. 10-05-2019 6 The positive phase input terminal of the operational amplifier OP1 is connected to the slider of the variable resistor VR1 connected to the input end of the volume control means 3a and grounded. The negative phase input terminal of the operational amplifier OP1 is connected between the output end of the operational amplifier OP1 and the output end of the volume control means 3a, is grounded, and is connected to the slider of the variable resistor VR2, and the level adjusted front channel signal FL / FR is input as a feedback signal. [0021] The second volume adjustment means 3b adjusts the level of the front channel signal FL / FR inputted from the first input terminal 1 or the surround channel signal SL / SR inputted from the second input terminal 2, The signal is output to the second amplification means 4b or the third amplification means 4c. In the present embodiment, the second volume adjustment means 3b includes an operational amplifier OP2, and the output end of the operational amplifier OP2 is connected to the output end of the volume adjustment means 3b. The positive phase input terminal of the operational amplifier OP2 is connected to the slider of the variable resistor VR3 connected to the input end of the volume control means 3b and grounded. The negative-phase input terminal of the operational amplifier OP2 is connected between the output end of the operational amplifier OP2 and the output end of the volume adjustment means 3b and is connected to the slider of the variable resistor VR4 grounded and the level-adjusted front channel signal An FL / FR or surround channel signal SL / SR is input as a feedback signal. [0022] The first amplification means 4a is connected to the subsequent stage of the first volume adjustment means 3a, and amplifies the front channel signal FL / FR level-adjusted by the first 10-05-2019 7 volume adjustment means 3a to the front speaker output terminal 6 Output. The second amplification means 4b is connected to the subsequent stage of the second volume adjustment means 3b, and amplifies the surround channel signal SL / SR level-adjusted by the second volume adjustment means 3b to the surround speaker output terminal 7 Output. The third amplification means 4c is connected in parallel with the second amplification means 4c at the subsequent stage of the second volume adjustment means 3b, and the front channel signal FL / FR adjusted in level by the second volume adjustment means 3b is It is amplified and output to the headphone output terminal 8. [0023] The switch SW1 is for switching the output path from the first amplification means 4a to the front speaker to the connected state or the disconnected state. In other words, the switch SW1 is connected between the first amplification means 4a and the front speaker output terminal 6, and the front channel signal FL / FR output from the first amplification means 4a is the front speaker output terminal 6 To allow or block the supply of That is, when the switch SW1 is turned on, the front channel signal FL / FR output from the first amplification means 4a is supplied to the front speaker output terminal 6, and when the switch SW1 is turned off, the front channel signal FL / FR The supply to the speaker output terminal 6 is blocked. [0024] The switch SW2 is for switching the output path from the second amplification means 4b to the surround source in the connection state or the non-connection state. In other words, the switch SW2 is connected between the second amplification means 4b and the surround speaker output terminal 7, and the surround channel signal SL / SR output from the second amplification means 4b is the surround speaker output terminal 7 To allow or block the supply of That is, when the switch SW2 is turned on, the surround channel signal SL / SR output from the second amplification means 4a is supplied to the surround speaker output terminal 7, and when the switch SW2 is turned off, surround of the surround channel signal SL / SR The supply to the speaker output terminal 7 is blocked. [0025] The switch SW3 is for switching the output path from the third amplification means 4c to the 10-05-2019 8 headphone to the connected state or the disconnected state. In other words, the switch SW3 is connected between the third amplification means 4c and the headphone output terminal 8, and the front channel signal FL / FR output from the third amplification means 4c is supplied to the headphone output terminal 8. To allow or block the supply of That is, when the switch SW3 is turned on, the front channel signal FL / FR output from the third amplification means 4c is supplied to the headphone output terminal 8, and when the switch SW3 is turned off, the headphone for the front channel signal FL / FR is output. The supply to the output terminal 8 is blocked. [0026] The switch IC 9 is connected between the first input end 1 or the second input end 2 and the first volume adjustment means 3a or the second volume adjustment means 3b, and the first input end 1 to the first input end 1 The input path of the volume adjustment means 3a is switched to the connection state or disconnection state, the input path from the first input terminal 1 to the second volume adjustment means 3b is switched to the connection state or disconnection state, and the second input end This is for switching the input path from 2 to the second volume adjustment means 3b to the connected state or the disconnected state. [0027] The switch IC 9 includes switches SW4 to SW6. The switch SW4 is connected between the first input terminal 1 and the first volume adjustment means 3a, and the input path from the first input terminal 1 to the first volume adjustment means 3a is connected or not connected Switch to In other words, the switch SW4 is for permitting or blocking the supply of the front channel signal FL / FR input from the first input terminal 1 to the first volume adjusting means 3a. That is, when the switch SW4 is turned on, the front channel signal FL / FR inputted from the first input terminal 1 is supplied to the first volume adjustment means 3a, and when the switch SW4 is turned off, the front channel signal FL / FR is outputted. The supply to the first volume adjustment means 3a is blocked. The switch SW5 is connected between the first input terminal 1 and the second volume adjustment means 3b, and the input path from the first input terminal 1 to the second volume adjustment means 3b is connected or not connected Switch to In other words, the switch SW5 is for permitting or blocking the supply of the front channel signal FL / FR input from the first input terminal 1 to the second volume adjustment means 3b. That is, when the switch SW5 is turned on, the front channel signal FL / FR inputted from the first input terminal 1 is supplied to the second volume adjusting means 3b, and when the switch SW5 is turned off, the front channel signal FL / FR is 10-05-2019 9 outputted. The supply to the second volume adjustment means 3b is blocked. The switch SW6 is connected between the second input terminal 2 and the second volume adjustment means 3b, and the input path from the second input terminal 2 to the second volume adjustment means 3b is connected or not connected Switch to In other words, the switch SW6 is for permitting or blocking supply of the surround channel signal SL / SR input from the second input terminal 2 to the second volume adjustment means 3b. That is, when the switch SW6 is turned on, the surround channel signal SL / SR input from the second input terminal 2 is supplied to the second volume adjustment means 3b, and when the switch SW6 is turned off, the surround channel signal SL / SR is output. The supply to the second volume adjustment means 3b is blocked. [0028] The buffer circuits 10a and 10c are connected between the first input terminal 1 or the second input terminal 2 and the switch IC 9, respectively. The buffer circuits 10b and 10d are connected between the switch IC and the first volume control unit 3a or the second volume control unit 3b. [0029] Headphones are connected to the headphone output terminal 8. When the headphones are connected, the headphone output terminal 8 outputs that the headphones and the headphone output terminal 8 are connected to the control means 5 as a connection signal. [0030] The control means 5 controls which speaker and / or headphone the front channel signal FL / FR or the surround channel signal SL / SR is to be output based on whether the headphone is connected to the headphone output terminal 8 or not. It is a thing. In other words, based on whether or not the headphones are connected to the headphone output terminal 8, the switch IC 9 switches the input path from the first input end 1 to the first volume adjustment means 3a, and the first input end 1 to the second input end. Control switching of the connection state or nonconnection state of the input path to the volume adjustment means 3b and the input path from the second input terminal 2 to the second volume adjustment means 3b, and the switches SW1 to SW3 Control the switching of the connection state or non-connection state of the output path from the second amplification means 4b to the surround speaker, and the output path from the third amplification means 4c to the headphone. Do. Specifically, based on the presence or 10-05-2019 10 absence of the connection signal from the headphone output terminal 8, the switches SW1 to SW3 are on / off controlled, and the switches SW4 to SW6 of the switch IC 9 are on / off controlled. The control means 5 also controls the level adjustment of the audio signal in the first volume adjustment means 3a and the second volume adjustment means 3b. [0031] Next, the operation of the multichannel amplifier having the above configuration will be described. [0032] The control means 5 determines whether a headphone is connected to the headphone output terminal 8 or not. Specifically, the control means 5 determines whether or not the headphone is connected to the headphone output terminal 8 depending on whether or not the connection signal is input from the headphone output terminal 8, and connects from the headphone output terminal 8. If a signal is input, it is determined that a headphone is connected to the headphone output terminal 8. [0033] FIG. 2 is a diagram showing control of the switches SW1 to SW3 and the switches SW4 to SW6 of the switch IC 9 by the control means 5. When the control means 5 determines that a headphone is not connected to the headphone output terminal 8, the switch SW1 and the switch SW4 of the switch IC 9 are turned on and the switch SW5 of the switch IC 9 is turned off. As a result, the input path from the first input end 1 to the second volume adjustment means 3b is disconnected, and the front channel signal FL / FR input from the first input end 1 is transmitted from the buffer circuit 10a, the switch It reaches the first amplification means 4 a via the IC 9, the first volume adjustment means 3 a and the buffer circuit 10 b, and is outputted to the front speaker output terminal 6. In addition, with regard to the switch SW2, the switch SW3, and the switch SW6 of the switch IC 9, when audio is output only from the front speaker, the switch SW6 of the switch IC 9 is turned off or the switch SW2 and the switch SW3 are turned off. When sound is also output from the surround speakers, the switch SW2 and the switch SW6 of the switch IC are turned on and the switch SW3 is turned off. 10-05-2019 11 [0034] When the control means 5 determines that a headphone is connected to the headphone output terminal 8, the switches SW1 and SW2 and the switches SW4 and SW6 of the switch IC9 are turned off, and the switch SW3 and the switch SW5 of the switch IC9 are turned on. As a result, the input path from the first input end 1 to the first volume adjustment means 3a and the input path from the second input end 2 to the second volume adjustment means 3b are disconnected, and the first The front channel signal FL / FR inputted from the input end 1 reaches the third amplification means 4c through the buffer circuit 10a, the switch IC, the buffer circuit 10d and the second volume adjustment means 3b, and the headphone output terminal 8 Output to [0035] As described above, in the multi-channel amplifier according to the present invention, when the headphones are not connected to the headphone output terminal 8, the buffer circuit from the first input terminal 1 for outputting the front channel signal FL / FR to the front speaker The audio signal path from the switch IC 9 to the first volume adjustment means 3a, the buffer circuit 10b and the first amplification means 4a to the front speaker output terminal 6 is not electrically connected to other audio signal paths The switch IC 9 and the switches SW1 to SW3 are on / off controlled by the control means 5 so that As a result, the adverse effects that occur when another audio signal path (especially the audio signal path to the headphone including the third amplification means 4c) is connected to the audio signal path to the front speaker, ie, the first amplification means 4a Therefore, it is possible to improve the sound quality of the sound output from the front speaker without the reduction of the input impedance of the above and the generation of the inductor component due to the wiring. [0036] Furthermore, in the multi-channel amplifier according to the present invention, when the headphone is connected to the headphone output terminal 8, the buffer circuit 10a is connected from the first input terminal 1 to output the front channel signal FL / FR to the headphone. The audio signal path from the switch IC 9, the first volume adjustment means 3b, the buffer circuit 10d and the third amplification means 4c to the headphone output terminal 8 comprises the first volume adjustment means 3a and the first amplification means 4a. The switch IC 9 and the switches SW1 to SW3 are on-off controlled by the control means 5 so that the audio signal path 10-05-2019 12 to the front speaker and the input terminal 2 are electrically disconnected. As a result, an adverse effect occurs when the audio signal path to the front speaker and the input end 2 are connected to the audio signal path to the headphone, that is, the input impedance of the third amplification means 4c is reduced, and the inductor component due to the wiring Can suppress the occurrence of noise, and can improve the sound quality of the sound output from the headphones. [0037] In the multi-channel amplifier according to the present invention, the input path from the first input end 1 to the first volume adjustment means 3a or the second volume adjustment means 3b, and the second input end 2 to the second one. Since a switch IC is used instead of a relay as means for switching the input path to the volume adjustment means 3b to the connected state or the disconnected state, it can be manufactured inexpensively. [0038] Also, buffer circuits 10a and 10c are connected between the first input end 1 or the second input end 2 and the switch IC 9, and the switch IC and the first volume adjustment means 3a or the second volume adjustment means 3b Distortion of the output of the multi-channel amplifier caused by the influence of the switch IC 9 can be suppressed by connecting the buffer circuits 10b and 10d between them, and as a result, the sound quality of the sound output from the front speaker can be further enhanced. The sound output from the surround speaker or the surround speaker can also be enhanced. [0039] In the present embodiment, when the control means 5 determines that a headphone is connected to the headphone output terminal 8, the switches SW1 and SW2 and the switches SW4 and SW6 of the switch IC9 are turned off, and the switches SW3 and IC9 are Although it has been described that the switch SW5 is turned on, the supply of the front channel signal to the front speaker is blocked by the switch SW4 of the switch IC 9, so the switch SW1 may be turned on. [0040] In the present embodiment, the switch SW1 is connected between the first amplification means 4a and the front speaker output terminal 6, and the switch SW2 is connected between the second amplification means 4b and the surround speaker output terminal 7 Although SW3 is connected between the third amplification means and the headphone output terminal 8, it is not limited thereto. 10-05-2019 13 For example, the switch SW1 may be switched to the first volume adjustment unit 3a and the first amplification unit 4a so that the path from the first volume adjustment unit 3a to the first amplification unit 4a can be switched to the connection state or the disconnection state. Connect between. In addition, the switch SW2 is used for the second second amplification means 4b and the surround speaker output so that the path from the second volume adjustment means 3b to the first amplification means 4b can be switched to the connection state or the disconnection state. Connect with terminal 7 The switch SW3 is connected between the third amplification means and the headphone output terminal 8 so that the path from the second volume adjustment means 3b to the third amplification means 4c can be switched to the connection state or the disconnection state. Connect to The switch SW2 and the switch SW3 are also connected to the second volume adjustment unit 3b so that the second amplification unit 4b and the third amplification unit are connected in parallel to the second volume adjustment unit 3b. Connected in parallel. The on / off control of the switches SW1 to SW3 in this case is the same as the on / off control in the above-described embodiment. [0041] As mentioned above, although embodiment of this invention was described, embodiment mentioned above is only an illustration for implementing this invention. Therefore, the present invention is not limited to the embodiment described above, and the embodiment described above can be appropriately modified and implemented without departing from the scope of the invention. [0042] The multi-channel amplifier of the present invention can be used in electronic devices for all applications, but can be suitably used in audio equipment and the like. [0043] 10-05-2019 14 FIG. 1 is a circuit diagram illustrating a multi-channel amplifier according to a preferred embodiment of the present invention. FIG. 6 is a diagram showing control of a switch by control means in a preferred embodiment of the present invention. It is a circuit diagram explaining the conventional multi-channel amplifier. Explanation of sign [0044] DESCRIPTION OF SYMBOLS 1 1st input terminal 2 2nd input terminal 3a 1st volume adjustment means 3b 2nd volume adjustment means 4a 1st amplification means 4b 2nd amplification means 4c 3rd amplification means 5 control means 6 front speaker Output terminal 7 Surround speaker output terminal 8 Headphone output terminal 9 Switch IC 10a to 10d Buffer circuit SW1 to SW6 Switch OP1, OP2 Operational amplifier VR1 to VR4 Variable resistor FL / FR Front channel signal SL / SR Surround channel signal 10-05-2019 15
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