JP2521653Y2 - Headphone switching circuit for multi-amplifier audio equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an improvement of a headphone switching circuit for muting a speaker sound when using headphones in a multi-amplifier audio device including, for example, a main amplifier, a surround amplifier, and a bass amplifier. .

<Prior Art> The following is a conventional headphone switching circuit for such a multi-amplifier audio device. This circuit is
When the headphone plug is inserted into the jack and the headphone is driven, the headphone jack has three or more switches that operate in conjunction with the plug insertion operation. That is, when the headphone plug is inserted into the jack, 2 out of the 3 or more switches
The switch of the circuit, for example, disconnects the main speaker and the surround speaker from the respective amplifiers to mute the main speaker and the surround speaker. on the other hand,
The switches of the remaining circuits, for example, activate the shoot circuit of the bus amplifier to mute the input signal of the bus amplifier and stop the driving of the bus speaker.

<Problems to be solved by the device> However, the headphone switching circuit of the conventional multi-amplifier audio device described above does not separate the main and surround speakers from the amplifier and the switching of the bus amplifier mute circuit in the headphone jack. Since the switch of another circuit is used, the switch of three circuits or more is required in the headphone jack, and there is a problem that the headphone jack becomes large and the cost becomes high.

Therefore, the purpose of this invention is to reduce the number of switch circuits in the headphone jack, thereby reducing the board area of the headphone jack, making the headphone jack smaller, and reducing the cost. To provide a circuit.

<Means for Solving the Problems> In order to achieve the above-mentioned object, the present invention provides a dedicated amplifier for an input left and right two-channel acoustic signal and an acoustic signal in a predetermined range different from the two-channel acoustic signal. Amplify with, and output signals from these multiple amplifiers
A speaker of a channel and a speaker of a predetermined range, or a headphone switching circuit of a multi-amplifier acoustic device for driving headphones, in which a sound signal input to an amplifier for a predetermined range is muted, and When the mute circuit for stopping the driving and the plug of the headphone are inserted, switching operation is performed by a jack electrically connecting the left and right channel amplifiers and the headphone, and the plug inserted in the jack. The left and right two-channel speakers and the left and right two-channel amplifiers are electrically separated, and a speaker mute switch for operating the mute circuit is provided.

<Operation> When a left and right two-channel acoustic signal and an acoustic signal in a predetermined range different from the two-channel acoustic signal are input, the plurality of input acoustic signals are respectively amplified by dedicated amplifiers, Left and right two-channel speakers and a speaker in a predetermined sound range are driven by output signals from the amplifier.

In this state, when the headphone plug is inserted into the jack, the jack electrically connects the left and right channel amplifiers and the headphone to drive the headphone. Further, the speaker mute switch is switched by the plug inserted in the jack. Then, the mute circuit is operated to mute the acoustic signal input to the amplifier for the predetermined sound range, and the driving of the speaker in the predetermined sound range is stopped. Furthermore, the left and right two-channel speakers and the left and right two-channel amplifiers are electrically separated.

Thus, the driving stop of the left and right two-channel speakers and the driving stop of the speakers in the predetermined sound range (that is, the driving stop of all the speakers) are performed by the same speaker mute switch in conjunction with the insertion operation of the headphone plug. . In that case, the jack only drives the headphones.

<Embodiment> Hereinafter, the present invention will be described in detail with reference to an illustrated embodiment.

FIG. 1 is a circuit diagram showing an embodiment of a multi-amplifier audio device, where a is the left channel (Lch) of the main amplifier IC2.
An input terminal for inputting an audio signal to the amplifier, b is an input terminal for inputting an audio signal to the right channel (Rch) amplifier of the main amplifier IC2, and c is a bass bass amplifier IC1
Is an input terminal to which an acoustic signal to is input. Also SP1
Rch main speaker, SP2 Lch main speaker, S
P3 is an Rch surround speaker, SP4 is an Lch surround speaker, SP5 is a bus speaker, Q1 is an NPN type mute transistor, and Q2 is a PNP type mute drive transistor. Further, HJ is a headphone jack into which a headphone plug (not shown) is inserted, and has a jack J and switches SW1 and SW2 which are speaker mute switches. Here, the mute transistor Q1, the mute drive transistor Q2, the switch SW1 and the resistors R1, R
2, the voice coil CL2 of the speaker SP2, and the ground terminal of the main speaker form a mute circuit that mutes an audio signal input to the bus amplifier IC1.

The Lch sound signal input from the input terminal a of the multi-amplifier audio device is amplified by the Lch amplifier of the main amplifier IC2, and is switched by the switch SW1 in the headphone jack HJ.
Is input to the voice coil CL2 of the main speaker SP2 and the voice coil CL4 of the surround speaker SP4 through the terminal 5 and the terminal 4. Then, sound is output from the main speaker SP2 and the surround speaker SP4. on the other hand,
The Rch sound signal input from the input terminal b is amplified by the Rch amplifier of the main amplifier IC2, passes between the terminal 8 and the terminal 7 of the switch SW2 in the headphone jack HJ, and the voice coil CL1 and the surround speaker of the main speaker SP1. Input to voice coil CL3 of SP3. Then, the sound is output from the main speaker SP1 and the surround speaker SP3. In addition, the acoustic signal input from the input terminal c is amplified by the bus amplifier IC1 and the bass speaker S
The voice is input to the voice coil CL5 of P5, and the voice is output from the bus speaker SP5.

In the above state, when the headphone plug is inserted into the headphone jack HJ when the headphones are used, the switch SW1 in the headphone jack HJ switches from the connection between terminals 5 and 4 to the connection between terminals 4 and 6. , The switch SW2 is switched from the connection between the terminal 8 and the terminal 7 to the connection between the terminal 7 and the terminal 9. As a result, the terminals 5 and 8 are in an open state and are not connected to the speakers SP1, SP2, SP3 and SP4, so that no sound is output from the speakers SP1, SP2, SP3 and SP4. However, the main amplifier IC2
Is connected to the terminal 3 of the jack J via the resistor R3, and the Rch amplifier of the main amplifier IC2 is connected to the jack J terminal 2 via the resistor R4. Therefore, the audio signals of Lch and Rch output from the main amplifier IC2 are jack J
The sound is output from the headphones by being supplied to the above-mentioned headphones through the terminals 3 and 2 and the plug of the headphones connected to the terminals 3 and 2. In this way, when the headphone plug is inserted into the headphone jack HJ, the sound can be heard from the above headphones, and at the same time, the speakers SP1, SP2, SP3
And the sound of SP4 disappears.

Further, when headphones are used, the terminals 4 and 6 of the switch SW1 are connected, so that the base of the mute drive transistor Q2 is connected between the resistor R2, the terminals 4 and 6 of the switch SW1 and the voice coil CL2 of the speaker SP2. Connected to the ground terminal. Then, the base of the mute drive transistor Q2 becomes "L" level. Then,
Since the mute drive transistor Q2 is a PNP type transistor, it is in the operating state.
The voltage + B of the emitter of the mute drive transistor Q2 is applied to the base of Q1. Therefore, the mute transistor Q1, which is an NPN transistor, is in the operating state, and the input terminal c is connected to the ground terminal. Then, the acoustic signal input to the bus amplifier IC1 is shot,
The sound of the bus speaker SP5 disappears.

That is, the headphone plug is the headphone jack
When inserted in the HJ, the switch in the headphone jack HJ
The connections between terminals 5 and 4 of SW1 and between terminals 8 and 7 of switch SW2 are opened, and the sounds of the main speakers SP1 and SP2 and the surround speakers SP3 and SP4 disappear. At the same time, the terminals 4 and 6 of the switch SW1 are connected, the mute circuit operates, and the sound of the bus speaker SP5 disappears. When using headphones, the sound of all speakers disappears.

In this way, since the driving stop of the main speaker SP2 and the surround speaker SP4 and the driving stop of the bass speaker SP5 are performed by one switch SW1, the switch circuit in the headphone jack HJ should be two switches SW1 and SW2. You can Therefore, the headphone jack can be downsized and the cost can be reduced.

In the above embodiment, the number of channels of the bus amplifier and the bus speaker is one, but the number of bus amplifiers may be two, Rch and Lch, and the Rch bus speaker and the Lch bus speaker may be driven respectively. In that case, for example, switch SW
While connecting the terminal 4-terminal 6 of 1 operates the mute circuit for Lch, the connection of the terminal 7-terminal 9 of the switch SW2 operates the mute circuit for Rch.
It suffices to stop the driving of the bus speaker.

<Effects of Device> As is clear from the above, the headphone switching circuit of the multi-amplifier audio device of the present invention includes a mute circuit for muting the audio signal to the amplifier in the predetermined range and stopping the driving of the speaker in the predetermined range. , Equipped with a speaker mute switch, disconnects the left and right two-channel speaker and amplifier when the headphone plug is inserted into the jack, and at the same time operates the mute circuit so that only the speaker mute switch is used for all speakers. Since it is possible to turn off the sound, the board area of the headphone jack can be reduced to reduce the size of the headphone jack, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of a multi-amplifier acoustic device according to the present invention. a, b, c …… input terminal IC1 …… bus amplifier IC2 …… main amplifier HJ …… headphone jack J …… jack SW1, SW2 …… switch SP1, SP2 …… main speaker SP3, SP4 …… surround speaker SP5… … Bass speaker CL1, CL2, CL3, CL4, CL5 …… Voice coil Q1 …… Mute transistor Q2 …… Mute drive transistor

Claims (1)

(57) [Scope of utility model registration request] 1. A left and right two-channel acoustic signal and an acoustic signal in a predetermined range different from the two-channel acoustic signal are respectively amplified by dedicated amplifiers, and the left and right channels are output by the output signals from the plurality of amplifiers. A speaker and a speaker in a predetermined range, or a headphone switching circuit of a multi-amplifier acoustic device for driving headphones, in which a sound signal input to an amplifier for a predetermined range is muted to drive the speaker in the predetermined range. When the mute circuit that stops the sound and the plug of the headphones are inserted, a switching operation is performed by a jack that electrically connects the left and right channel amplifiers and the headphones, and the plug inserted in the jack. Left and right 2 channel speaker and left and right 2
A headphone switching circuit for a multi-amplifier audio device, which is equipped with a speaker mute switch that electrically disconnects a channel amplifier and operates the mute circuit.