JPH032989Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention provides two-channel playback input signals of left and right channels in a two-channel stereo playback device, etc., and a third playback input signal to the two-channel playback input signals. The present invention relates to a multi-channel amplifier connection device that performs switching amplification of a three-channel reproduction input signal with a 3-channel input signal.

[Conventional technology]

Generally, in digital audio systems such as digital audio disk players and PCM recorders, high-frequency components are superimposed on the low-frequency components of large inputs and recorded, and when playing back signals arranged in this way, Because distortion is more likely to occur in high-frequency components than in low-frequency components, an amplifier that can separate and amplify the low-frequency components and mid-high frequency components separately is required, and the dynamic range of the digital audio system also increases. In addition to the fact that it is considerably wider than a normal two-channel stereo playback device, a multi-channel amplifier is required.

Furthermore, an amplifier that can be switched between a 2-channel mode and a mode of 3 or more channels would be very useful so that it can be used with both a normal 2-channel stereo playback device and a digital audio system such as the one described above.

Conventionally, as described in Japanese Utility Model Publication No. 54-20961, in a 4-channel stereo playback device, the circuit is switched from 4-channel mode to 2-channel mode BTL by operating the first and second operating sections for switch control. A device has been proposed which is characterized in that it prevents the speaker from being damaged due to the flow of a large current using an input attenuation circuit when switching modes.

[Problem that the invention attempts to solve]

However, the device described in the above publication switches between 4-channel mode and 2-channel mode by operating a switch, and does not amplify and output low-frequency components and mid-high frequency components separately, as described above. However, there is a problem in that input attenuation to prevent damage to the speaker when switching modes must be performed by operating both the first and second operating sections.

[Means for solving problems]

This invention includes a first state in which first to fourth amplifiers, the first amplifier and the second amplifier, and the third amplifier and the fourth amplifier are connected BTL, respectively;
the first or second amplifier and the third or fourth amplifier;
a switching means for switching between a second state in which the amplifier is BTL connected; and a switching means for switching the amplifier to a second state in which the amplifier is connected to the BTL;
The gains of the first and second amplifiers and the gains of the third and fourth amplifiers connected BTL match,
The gain of the first or second amplifier and the third or fourth amplifier connected BTL in the second state matches the gain of the remaining second or first amplifier and fourth or third amplifier. This is a multi-channel amplifier connection device equipped with a gain adjustment resistor selected as follows.

[Effect]

Next, I will explain the effect of this idea.
By operating the switching means, the connection of each amplifier is switched to the first or second state, and at the same time as the switching between the 2-channel mode and the 3-channel mode, the gain of the amplifier for each channel is switched.

〔Example〕

Next, a drawing showing an embodiment of this invention will be described.

In the drawings, 1 to 4 are the first to fourth amplifiers, 5
~7 are the first, fourth, and second amplifiers 1, 4, respectively.
The first, second and third channel input terminals are connected to the non-inverting input terminal (+) of No. 2, and one end of 8-11 is the non-inverting input terminal (+) of the first to fourth amplifiers 1-4.
and the other end is grounded.
~The fourth resistor, 12-15, has one end connected to each amplifier 1-4.
The fifth to eighth resistors, which are gain adjustment resistors of each amplifier 1 to 4, are connected to the inverting input terminal (-) of the amplifiers 1 to 4, and the other end is grounded. 9th to 9th resistors, each of which is a gain adjustment resistor of each amplifier 1 to 4, are connected to the terminal (-) and the other end is connected to the output terminal of each amplifier 1 to 4;
12th resistor, 20 are first and second contacts 20a, 20b
are first switches connected to the output terminals of the first and second amplifiers 1 and 2, respectively, and 21 is a first contact 21a.
is open and the second contact 21b is connected to the output terminal of the second amplifier 2, 22 is the first switch, and the second contacts 22a, 22b are the fourth and third amplifiers 4, 3.
The switches 20 to 22 are connected to the respective output terminals of the switches 20 to 22, and the switches 20 to 22 constitute a switching means 23.

24 to 26 are the 13th inverting input terminals, one end of which is connected to the switching pieces 20c to 22c of each switch 20 to 22.
~15th resistor, 27-30 are each amplifier 1~
The first to fourth connection terminals 31 to 33 connected to the output terminals 4 and 33 are the first to third speakers, and in the first state, the switching pieces 20c to 22c of each switch 20 to 22 are the first contacts. When switching to the 20a to 22a side, both ends of the first speaker 31 are connected to the first and second connection terminals 27 and 28, respectively, and both ends of the second speaker 32 are connected to the third and second connection terminals 27 and 28, respectively.
are connected to the fourth connection terminals 29 and 30, respectively, and when the second state, that is, the switching pieces 20c to 22c of each switch 20 to 22 are switched to the second contacts 20b to 22b side, the first and second speaker 31,
One end of 32 is connected to the first and fourth connection terminals 27, 30, the other end is grounded, and the third
Both ends of the speaker 33 are connected to the second and third connection terminals 28,
29.

Note that the resistance values R ₁ , , of the first to fourth resistors 8 to 11 are
R ₂ , R ₃ , R ₄ are equal, the resistance values R ₅ , R ₆ , R ₇ , R ₈ of the 5th to 8th resistors 12 to 15 are equal, and the resistances of the 9th to 12th resistors 16 to 19 are equal. Value R ₉ ,
R ₁₀ , R ₁₁ , and R ₁₂ are equal, the resistance values R 10 and R ₁₃ of the 10th and 13th resistors 17 and ₂₄ are equal, and the 11th and
Resistance value R ₁₁ of the 14th and 15th resistors 18, 25, 26,
R ₁₄ and R ₁₅ are selected equally, and R ₉ ≫ _{R 5} .

Then, as shown in FIG. 1, each switch 20
~22 switching pieces 20c~22c as the first contact 20a
-22a side, each amplifier 1-4 is connected to the first state, that is, the first amplifier 1 and the second amplifier 2 are connected BTL, and the third
The amplifier 3 and the fourth amplifier 4 are BTL connected, and by inputting the left and right channel playback signals of the normal two-channel stereo playback signal through the first and second channel input terminals 5 and 6, the first, Second
The left and right channel reproduction signals amplified by the amplifiers 1 and 2 and the third and fourth amplifiers 3 and 4 are output from the first and second speakers 31 and 32, respectively.

At this time, the gain G ₁₂ of the first and second amplifiers 1 and 2 connected in BTL is the same as that of the fifth and sixth resistors 12 and 1.
As mentioned above, the relationship between the resistance values of the third, ninth, and tenth resistors 16 and 17 is as follows: R ₅ = R ₆ , R ₉ = R ₁₀ ,
Furthermore, since R ₉ ≫ R ₅ , G ₁₂ = 2×R ₉ /R ₅ , and the gain G ₃₄ of the third and fourth amplifiers 3 and 4, which are similarly connected in BTL, is the same as that of the seventh and eighth resistors 14, 1
As described above, the relationship between the resistance values of the 5th, 11th, and 12th resistors 18 and 19 is as follows: R ₇ =R ₈ (=R ₅ ), R ₁₁ =R ₁₂
(=R ₉ ), and R ₁₂ (=R ₉ )≫R ₈ (=R ₅ ), so G ₃₄ = 2×R ₁₂ /R ₈ =2×R ₉ /R ₅ , and the first and The gain G ₁₂ of the BTL circuits of the second amplifiers 1 and 2 is equal to the gain G ₃₄ of the BTL circuits of the third and fourth amplifiers 3 and 4.

Next, as shown in FIG.
~22 switching pieces 20c~22c as the second contact 20b
When switching to the ~22b side, each amplifier 1 to 4 is connected to the second state, that is, the second amplifier 2 and the third amplifier 3 are connected BTL, and the output is input via the first and second channel input terminals 5 and 6. Inputs the left and right channel playback signals of the normal 2-channel stereo playback signal, and also inputs the third channel input terminal 7.
By inputting the third channel signal through the , the left and right channel reproduction signals amplified by the first amplifier 1 and the fourth amplifier 4 are outputted from the first and second speakers 31 and 32, respectively. , the third channel signal amplified by the second and third amplifiers 2 and 3 is transmitted to the third speaker 3.
Output from 3.

At this time, the gain of the first and fourth amplifiers 1 and 4 is
G ₁ and G ₄ are respectively G ₁ = R ₅ + R ₉ /R ₅ and G ₄ = R ₈ + R ₁₂ /R ₈ , and the fifth and eighth resistors 12 and 15 and the ninth,
As described above, the relationship between the resistance values of the twelfth resistors 16 and 19 is R ₅ = R ₈ , R ₉ = R ₁₂ , and R ₉ ≫ _{R 5}
Therefore, G ₁ = R ₉ /R ₅ , G ₄ = R ₁₂ /R ₈ = R ₉ /
R ₅ , and the second and third amplifiers 2, connected by BTL,
The gain G ₂₃ of 3 is: G ₂₃ = 2×1/1/R ₁₀ +1/R ₁₃ /R ₆ =
2×R ₁₀・R ₁₃ /R ₁₀ +R ₁₃ /R ₆ =2×R ₁₀・R ₁₃ /R ₆ (R ₁₀
+R ₁₃ ), and the fifth and sixth resistors 12 and 13 and the ninth resistor
Since the relationship between the resistance values of the 10th and 13th resistors 16, 17, and 24 is R ₅ = R ₆ , R ₉ = R ₁₀ = R ₁₃ , the gain G ₂₃
is, G ₂₃ = 2×R ₉・R ₉ /R ₅ (R ₉ + R ₉ ) = 2×R ₉・R ₉ /2・R ₅・R ₉ = R ₉ /R ₅ , and the first amplifier 1, Gain of 4th amplifier 4
The gains G ₂₃ of the BTL circuits of G ₁ and G ₄ and the second and third amplifiers 2 and 3 are respectively equal, and become 1/2 of the gains G ₁₂ and G ₃₄ in the first state.

Note that in the first and second states described above, the first amplifier 1 and the second amplifier 2 may be replaced, and the third amplifier 3 and the fourth amplifier 4 may be replaced.

[Effect of idea]

Therefore, according to this invention, the switching means 23
By simply operating the , you can switch the connection of each amplifier 1 to 4 between 2 channel mode and 3 channel mode, and at the same time switch the gain of the amplifier for each channel. It becomes possible to amplify and output the components separately, and the effect is remarkable.

[Brief explanation of drawings]

The drawings show one embodiment of the multi-channel amplifier connection device of this invention, and FIGS. 1 and 2 are connection diagrams in different states. 1-4...Amplifier, 12-19...5th-12th
Resistor, 23...Switching means.

Claims (1)

[Scope of utility model registration request] A first state in which the first to fourth amplifiers, the first amplifier and the second amplifier, and the third amplifier and the fourth amplifier are each connected BTL, and the first or second amplifier and the third or fourth amplifier. of
a switching means for switching to a second state in which the BTL connection is made, and a gain of the first and second amplifiers and a gain of the third and fourth amplifiers, which are connected in the BTL connection in the first state, match; 2
The gain of the first or second amplifier and the third or fourth amplifier connected BTL is matched with the gain of the remaining second or first amplifier and fourth or third amplifier in the state of A multi-channel amplifier connection device equipped with a gain adjustment resistor.