JP2018160712A - Music playback device, plug, headphone, and adapter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect insertion of an unbalance plug when a jack is used for balancing and unbalance use.SOLUTION: A DAP 1 includes a jack 7 into which a balancing plug or an unbalance plug 101 having a resistor R101 connected between the contacts of the two inverted channels is inserted, a comparator 8 that compares a voltage of an inverted R channel with a predetermined threshold value, and a SoC2. The SoC 2 applies a predetermined voltage to an inverted L channel. In the SoC 2, when a comparator 8 detects that the voltage of the inverted R channel is equal to or larger than the predetermined threshold value, the comparator 8 determines that the unbalance plug 101 is inserted into the jack.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a music playback device, a plug, headphones, and an adapter having a balanced output and an unbalanced output.

  FIG. 4 is a diagram showing a 5-pole plug with a diameter of 4.4 mm for balanced output. As shown in FIG. 3, from the tip of the plug, a non-inverted L channel (L +), an inverted L channel (L−), a non-inverted R channel (R +), an inverted R channel (R−), a ground ( GND). Since the 5-pole plug has ground (GND), unbalanced output is possible using non-inverted L channel (L +) and ground (GND), non-inverted R channel (R +) and ground (GND). is there. In a music playback apparatus having a balance output and an unbalance output, a balance jack and an unbalance jack are provided separately (see, for example, Patent Document 1), but at the same time, a balance jack and an unbalance jack are provided. There is a problem that a plug is inserted into the jack for balance. Further, if the balance jack and the unbalance jack are separate, the space is required. Therefore, it is conceivable that the jack is equipped with only a highly reliable 4.4 mm jack, and this jack can be used for both balancing and unbalance. In addition, since the plug for 4.4 mm unbalance does not exist now, the adapter converted into the plug for unbalance is needed.

  The applicant has applied for Japanese Patent Application No. 2015-171945. The invention according to this patent application includes two D / A converters and two amplifier circuits. One D / A converter (hereinafter referred to as “DAC”) is for a non-inverted audio signal, and D / A converts a digital audio signal into an analog audio signal. The other DAC is for an inverted audio signal, and D / A converts the digital audio signal into an analog audio signal. One amplifier circuit amplifies a non-inverted analog signal obtained by D / A conversion of one DAC. The other amplifier circuit amplifies the inverted analog audio signal obtained by inverting the non-inverted analog audio signal D / A converted by the other DAC. In the case of unbalanced output, power consumption is reduced by turning off the other DAC and the other amplifier circuit.

JP 2013-005291 A

  However, when the jack is used for both balance and unbalance, it is necessary to detect that an unbalance plug has been inserted in order to turn off the DAC and amplifier circuit.

  An object of the present invention is to make it possible to detect that an unbalanced plug has been inserted when a jack is used for both balance and unbalance.

  A music playback device according to a first aspect of the present invention is a jack and an inversion other channel into which a balance plug or an unbalance plug in which a resistor is connected between the contacts of the inversion two channels is inserted. And a control unit that compares the voltage of the second channel with a predetermined threshold, the control unit applies a predetermined voltage to one of the channels of inversion, and the comparison unit When it is detected that the voltage is equal to or higher than a predetermined threshold, it is determined that an unbalanced plug is inserted into the jack.

  In the present invention, the control unit applies a predetermined voltage to one channel of inversion. Here, when an unbalanced plug in which a resistor is connected between the contact points of the two inverted channels is inserted into the jack, a voltage is generated in the other inverted channel. For this reason, the comparison unit can detect that the voltage of the other channel is equal to or higher than a predetermined threshold. When the comparison unit detects that the voltage of the other channel is greater than or equal to a predetermined threshold, the control unit determines that an unbalanced plug has been inserted into the jack. Thus, according to the present invention, it is possible to detect that an unbalanced plug has been inserted even when the jack is used for both balancing and unbalance.

  A music playback device of a second invention is the music playback device of the first invention, wherein the control unit balances when the comparison unit detects that the voltage of the other channel is less than a predetermined threshold value. It is judged that the plug for use is inserted into the jack.

  When a balance plug is inserted into the jack, even if a voltage is applied to one of the inverted channels, no voltage is generated on the other inverted channel. For this reason, the comparator can detect that the voltage of the other channel is less than the predetermined threshold. When the comparison unit detects that the voltage of the other channel is less than a predetermined threshold, the control unit determines that a balancing plug has been inserted into the jack. As described above, according to the present invention, even when the jack is used for both balancing and unbalance, it can be detected that the balancing plug has been inserted.

  A music playback device of a third invention is the music playback device of the first or second invention, wherein the first D / A converter for D / A converting a digital audio signal of two left and right channels into an analog audio signal, and the first D A first amplifying circuit for amplifying the left and right channel analog audio signals D / A converted by the A / A converter, and a second D / A for D / A converting the left and right channel digital audio signals into the left and right channel analog audio signals And a second amplifying circuit for amplifying the left and right two-channel inverted analog audio signals obtained by inverting the left and right two-channel analog audio signals D / A converted by the second D / A converter. .

  A music playback device of a fourth invention is the music playback device of the third invention, wherein when the control unit determines that an unbalanced jack is inserted, the second D / A converter and the second amplification And the circuit is turned off.

  In the present invention, the control unit turns off the second D / A converter and the second amplifier circuit when determining that the unbalanced jack is inserted. Thereby, useless power consumption can be reduced.

  A music playback device of a fifth invention is the music playback device of the third or fourth invention, wherein the first amplifier circuit includes a first amplifier for amplifying a left channel analog audio signal, and a right channel analog audio signal. A second amplifier that amplifies the inverted analog audio signal of the left channel, and a fourth amplifier that amplifies the inverted analog audio signal of the right channel. The first amplifier is connected to a contact for a non-inverted left channel of the jack, the second amplifier is connected to a contact for a non-inverted right channel of the jack, and the third amplifier is The fourth amplifier is connected to a contact for the right channel of inversion of the jack, and is connected to a contact for the left channel of inversion of the jack.

  A music playback device according to a sixth aspect is the music playback device according to any one of the first to fifth aspects, wherein the control unit applies a predetermined voltage when applying a predetermined voltage to one of the inverted channels. The other channel of the inversion not to be performed is fixed to 0V.

  A music playback device of a seventh invention is the music playback device of any one of the third to fifth inventions, wherein the control unit applies a predetermined voltage when applying a predetermined voltage to one of the inverted channels. The amplifying circuit for inversion that is not performed is muted.

  The plug of the eighth invention is an unbalanced plug having a five-pole contact, and the five-pole contact has the same contact arrangement as that of the balance plug, and the left of the inversion in the balance plug A resistor is connected between the contact for the channel and the contact for the inverted right channel.

  A headphone of a ninth invention includes the plug of the eighth invention. The headphone is a concept including an earphone.

  An adapter according to a tenth aspect of the invention is an adapter connected to an unbalanced plug, comprising a five-pole contact, wherein the five-pole contact has the same contact arrangement as the balance plug, When a resistor is connected between the contact for the inverted left channel and the contact for the inverted right channel in the plug, and the unbalanced plug is connected, the contact for the non-inverted left channel is The contact of the left channel of the unbalanced plug contacts the contact of the right channel of the unbalanced plug, and the contact of the non-inverted right channel contacts the contact of the right channel of the unbalanced plug.

  According to the present invention, it is possible to detect that an unbalanced plug has been inserted even when the jack is used for both balancing and unbalance.

1 is a block diagram showing a configuration of a digital audio player according to an embodiment of the present invention. It is a figure which shows the state by which the plug for unbalance is inserted in the jack. It is a block diagram which shows the structure of the digital audio player which concerns on a modification. It is a figure which shows the 5 pole plug of diameter 4.4mm for balance outputs.

  Hereinafter, embodiments of the present invention will be described. FIG. 1 is a block diagram showing a configuration of a digital audio player (hereinafter referred to as “DAP”) according to an embodiment of the present invention. The DAP 1 (music playback device) includes a SoC (System on Chip) 2, D / A converters (hereinafter referred to as “DAC”) 3 and 4, amplification circuits 5 and 6, a jack 7, and a comparator 8. SoC2 (control part) has CPU (Central Processing Unit), DSP (Digital Signal Processor), memory, etc., and controls each part which comprises DAP1.

  LR (left and right) 2-channel digital audio data (digital audio signal) in the I2S format is input from the SoC 2 to the positive-side (non-inverted signal) DAC 3. The DAC 3 D / A converts the digital audio data of the LR2 channel into analog audio data (analog audio signal) of the LR2 channel. LR2 channel analog audio data D / A converted by the DAC 3 is input to the positive side amplifier circuit 5 (first amplifier circuit). The amplifier circuit 4 amplifies analog audio data of the LR2 channel.

  Specifically, the amplifier circuit 4 includes amplifiers 9 and 10. The amplifier 9 (first amplifier) amplifies the L channel analog audio data. The amplifier 9 is connected to a non-inverted L channel contact (L +) of the jack 7 via a resistor R1. Therefore, L channel analog audio data is output to the non-inverted L channel contact of the jack 7. The amplifier 10 (second amplifier) amplifies R channel analog audio data. The amplifier 10 is connected to a non-inverted R channel contact (R +) of the jack 7 through a resistor R2. Therefore, R channel analog audio data is output to the non-inverted R channel contact of the jack 7.

  The LR2 channel digital audio data in the I2S format is input from the SoC2 to the negative side (for inverted signal) DAC4. The DAC 3 D / A converts the digital audio data of the LR2 channel into analog audio data of the LR2 channel. The negative amplifier circuit 6 (second amplifier circuit) receives LR2 channel inverted analog audio data obtained by inverting the LR2 channel analog audio data D / A converted by the DAC 4. The amplifier circuit 6 amplifies the inverted analog audio data of the LR2 channel.

  Specifically, the amplifier circuit 6 includes amplifiers 11 and 12. The amplifier 11 (third amplifier) amplifies the inverted analog audio data of the L channel. The amplifier 11 is connected to an inverted L channel contact of the jack 7 via a resistor R3. Therefore, the inverted analog audio data of the L channel is output to the contact for the inverted L channel of the jack 7. The amplifier 12 (fourth amplifier) amplifies the inverted analog audio data of the R channel. The amplifier 12 is connected to the contact for the inverted R channel of the jack 7 via the resistor R4. Accordingly, the inverted analog audio data of the R channel is output to the contact for the inverted R channel of the jack 7.

  Here, a linear regulator (not shown) supplies a power supply voltage to the DACs 3 and 4 and the amplifier circuits 5 and 6. In the case of an unbalanced output, the SoC 2 controls the power down pin in the DAC 4 and the amplifier circuit 6 to turn off the DAC 4 and the amplifier circuit 6.

  The jack 7 has a 5-pole contact. The five-pole contacts are for the non-inverted L channel (L +), the inverted L channel (L-), the non-inverted R channel (R +), the inverted R channel (R-), and ground from the top. (GND). A plug for balancing or a plug 101 for unbalance is inserted into the jack 7. The unbalanced plug 101 may be, for example, an adapter connected to a 3.5 mm unbalanced plug, or a plug connected to unbalanced headphones.

  The unbalanced plug 101 has the same contact arrangement as the balanced headphones shown in FIG. In the unbalanced plug, a resistor R101 is connected between an inverted L channel contact (L-) and an inverted R channel contact (R-) in the balance plug. .

  The comparator 8 (comparator) compares the inverted R channel voltage with a predetermined threshold value (0.01 V). The comparator 8 determines that the potential of the output terminal is high when the voltage of the inverted R channel is equal to or higher than a predetermined threshold (0.01 V), and the voltage of the inverted R channel is higher than the predetermined threshold. To detect. Further, when the voltage of the inverted R channel is less than a predetermined threshold value (0.01 V), the comparator 8 keeps the potential of the output terminal low, and the voltage of the inverted R channel is less than the predetermined threshold value. Is detected.

  The non-inverting input terminal (+) of the comparator 8 is connected between the resistor R4 and the inverting R channel contact (R−) of the jack 7. A voltage generated in the inverted R channel is input to the non-inverting input terminal (+) of the comparator 8. The inverting input terminal (−) of the comparator 8 is connected to the resistors R6 and R7. The resistor R6 is connected to the power supply VDD (1.8V). The resistor R7 is connected to the ground. 0.01 V is input to the inverting input terminal (−) of the comparator 8. The output terminal of the comparator 8 is connected to the SoC2.

  The DAP 1 has a detection contact 13 for detecting plug insertion / extraction. The detection contact 13 is connected to the power supply VDD (1.8V) via the resistor R8. When the plug is not inserted in the jack 7, the detection contact 13 is in contact with the insulation contact 14 connected to the ground. For this reason, the potential between the resistor R8 and the detection contact 13 is low. In this case, the SoC 2 determines that no plug is inserted. When the plug is inserted into the jack 7, the detection contact 13 is separated from the insulation contact 14. For this reason, the potential between the resistor R8 and the detection contact 13 is high. In this case, the SoC 2 determines that a plug is inserted.

  After the plug is inserted, the SoC 2 determines whether the inserted plug is a balance plug or an unbalance plug 101. The SoC 2 mutes the positive-side DAC 3 (mute: on). The SoC 2 does not mute the negative-side DAC 3 (mute: off). Next, the SoC 2 applies a predetermined voltage (2 V) to the inverted L channel. SoC2 fixes the inverted R channel to 0V. Here, the PCM data of the L channel is a negative value. Further, since it is not known what kind of connection is made, a sudden rise is avoided, and a voltage is applied over a period of several milliseconds.

  When a balancing plug is inserted into the jack 7, no voltage is generated in the inverted R channel. For this reason, the output of the comparator 8 is low. In this case, the SoC 2 determines that a balancing plug is inserted into the jack 7. In order to obtain a balanced output, the SoC 2 turns on the DACs 3 and 4 and the amplifier circuits 5 and 6. Even if a balance plug is inserted into the jack 7 and a voltage is applied between the inverted L channel and the inverted R channel, almost no sound is output from the balance headphones.

  When the unbalanced plug 101 is inserted into the jack 7, as shown in FIG. 2, there is a resistance between the inverted L channel contact and the inverted R channel contact of the jack 7. R101 is inserted. The SoC 2 mutes the positive-side DAC 4 (mute: on). The SoC 2 does not mute the negative-side DAC 3 (mute: off). Next, the SoC 2 applies a predetermined voltage (2 V) to the inverted L channel. SoC2 fixes the inverted R channel to 0V. In this case, the voltage generated in the inverted R channel is 2 × 3.3 / (27 + 3.3 + 3.3) = 0.196 (V).

  As described above, a voltage equal to or higher than a predetermined threshold (0.1 V) is generated in the inverted R channel. For this reason, the output of the comparator 8 is high. In this case, the SoC 2 determines that the unbalanced plug 101 is inserted into the jack 7. In order to obtain an unbalanced output, the SoC 2 turns on the DAC 3 and the amplifier circuit 5 and turns off the DAC 4 and the amplifier circuit 6.

  As described above, in the present embodiment, the SoC 2 applies a predetermined voltage to the inverted L channel. Here, when the unbalanced plug 101 in which the resistor R101 is connected between the contacts of the two inverted channels is inserted into the jack 7, a voltage is generated in the inverted R channel. For this reason, the comparator 8 can detect that the voltage of the R channel is equal to or higher than the predetermined threshold. When the comparator 8 detects that the R channel voltage is equal to or higher than a predetermined threshold, the SoC 2 determines that the unbalanced plug 101 is inserted into the jack 7. Thus, according to the present embodiment, it is possible to detect that the unbalanced plug 101 has been inserted even when the jack 7 is used for both balancing and unbalance.

  Further, when a balancing plug is inserted in the jack 7, even if a voltage is applied to the inverted L channel, no voltage is generated in the inverted R channel. Therefore, the comparator 8 can detect that the voltage of the R channel is less than the predetermined threshold value. When the comparator 8 detects that the voltage of the R channel is less than a predetermined threshold, the SoC 2 determines that a balancing plug has been inserted into the jack 7. Thus, according to the present embodiment, even when the jack 7 is used for both balancing and unbalance, it can be detected that a balancing plug has been inserted.

  In the present embodiment, the SoC 2 turns off the DAC 4 and the amplifier circuit 6 when determining that the unbalanced jack 7 is inserted. Thereby, useless power consumption can be reduced.

  As mentioned above, although embodiment of this invention was described, the form which can apply this invention is not restricted to the above-mentioned embodiment, As suitably illustrated in the range which does not deviate from the meaning of this invention so that it may illustrate below. It is possible to make changes.

  In the above-described embodiment, the SoC 2 applies a predetermined voltage to the inverted L channel. Not limited to this, the SoC 2 may apply a predetermined voltage to the inverted R channel. In this case, the comparator 8 compares the inverted L channel voltage with a predetermined threshold value. SoC2 fixes the inverted L channel to 0V. Alternatively, as shown in FIG. 3, a switch SW1 may be provided between the amplifier 11 and the resistor R3 so that the switch SW1 is turned off and the output of the inverted L channel is set to high impedance. In this way, since the L channel output voltage appears in the L channel as it is, the detection becomes very simple.

  When the adapter is connected to the 3.5 mm unbalanced plug described in the above embodiment, the adapter has the following configuration. The adapter has a 5-pole contact. The contact of 5 poles is the same contact arrangement as the balance plug. A resistor is connected between the contact for the inverted L channel and the contact for the inverted R channel in the balance plug. When an unbalanced plug is connected to the adapter, the non-inverted L-channel contact contacts the L-channel contact of the unbalanced plug. The contact for the non-inverted R channel contacts the contact of the R channel of the unbalanced plug.

  In the above-described embodiment, the DAP is exemplified as the music playback device. Not limited to this, a tablet PC, a smartphone (mobile phone), a headphone amplifier, a USB DAC, or the like may be used.

  The present invention can be suitably employed in a music playback device, a plug, a headphone, and an adapter having a balanced output and an unbalanced output.

1 DAP (music player)
2 SoC (control unit)
3 DAC (1st D / A converter)
4 DAC (second D / A converter)
5 Amplifier circuit (first amplifier circuit)
6 Amplifier circuit (second amplifier circuit)
7 Jack 101 Unbalanced plug

Claims (10)

A jack into which a plug for balancing or an unbalanced plug in which a resistor is connected between the contacts of two inverted channels is inserted;
A comparison unit that compares the voltage of the other channel of the inversion with a predetermined threshold;
A control unit,
The controller is
Apply a predetermined voltage to one channel of inversion,
When the comparison unit detects that the voltage of the other channel is equal to or higher than a predetermined threshold value, it determines that an unbalanced plug is inserted into the jack.   2. The control unit according to claim 1, wherein when the comparison unit detects that the voltage of the other channel is less than a predetermined threshold, the control unit determines that a balancing plug is inserted into the jack. The music playback device described. A first D / A converter that D / A converts a digital audio signal of two left and right channels into an analog audio signal;
A first amplifier circuit that amplifies the left and right channel analog audio signals D / A converted by the first D / A converter;
A second D / A converter that D / A converts a digital audio signal of two left and right channels into an analog audio signal of two left and right channels;
A second amplifying circuit for amplifying the left and right two-channel inverted analog audio signals obtained by inverting the left and right two-channel analog audio signals D / A converted by the second D / A converter;
The music playback device according to claim 1, further comprising:   4. The music reproduction according to claim 3, wherein the control unit turns off the second D / A converter and the second amplifier circuit when determining that an unbalanced jack is inserted. 5. apparatus. The first amplifier circuit includes:
A first amplifier for amplifying the left channel analog audio signal;
A second amplifier for amplifying the right channel analog audio signal;
The second amplifier circuit includes:
A third amplifier for amplifying the inverted analog audio signal of the left channel;
A fourth amplifier for amplifying the inverted analog audio signal of the right channel;
The first amplifier is connected to a contact for a non-inverted left channel of the jack;
The second amplifier is connected to a contact for a non-inverted right channel of the jack;
The third amplifier is connected to a contact for the left channel of the jack inversion,
5. The music playback device according to claim 3, wherein the fourth amplifier is connected to a contact for the right channel of the inversion of the jack. 6.   The said control part fixes the other channel of the inversion which does not apply a predetermined voltage to 0V, when applying a predetermined voltage to one channel of inversion, The any one of Claims 1-5 characterized by the above-mentioned. The music playback device described in 1.   The said control part mutes the inversion amplifier circuit which does not apply a predetermined voltage, when applying a predetermined voltage to one channel of inversion, The any one of Claims 3-5 characterized by the above-mentioned. Music player. An unbalanced plug with a 5-pole contact,
The five-pole contact has the same contact arrangement as the balance plug,
A plug in which a resistor is connected between a contact for an inverted left channel and a contact for an inverted right channel in a balance plug.   An unbalanced headphone comprising the plug according to claim 8. An adapter connected to an unbalanced plug,
With 5 contacts
The five-pole contact has the same contact arrangement as the balance plug,
In the balance plug, a resistor is connected between the contact for the inverted left channel and the contact for the inverted right channel,
When the unbalanced plug is connected,
The non-inverted left channel contact contacts the left channel contact of the unbalanced plug,
A non-inverted right channel contact is in contact with a right channel contact of the unbalanced plug.

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