JP2011109538A - Audio signal output device and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an audio signal output device capable of reducing power consumption in the standby period in the audio signal output device to attenuate the audio signal. <P>SOLUTION: The audio signal output device to enable muting function by attenuating the audio signal includes an attenuation circuit for setting attenuation level, according to an input base current value; a power supply for feeding the electric power to drive the audio signal output device and reducing the feeding level of electric power from the power supply during the standby period; and a base current setting circuit for setting a base current value, according to the feed level of electric power from the power supply and feeding the preset base current to the attenuation circuit. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an audio output device that attenuates audio by a set attenuation amount, and a display device.

  In recent years, an audio output device that outputs audio includes a plurality of audio output terminals in addition to an RL speaker provided in the device itself. Further, in the audio output device, in order to put each audio output unit (speaker, audio output terminal) in a silent state (mute setting), the audio is attenuated by an attenuation circuit provided therein to perform mute setting.

  The attenuation circuit described above includes a transistor and a resistor, and the attenuation amount of the audio signal is set in proportion to the value of the input base current. That is, in order to attenuate the audio signal by a predetermined attenuation amount, it is necessary to input a predetermined amount of base current to the attenuation circuit (see, for example, Patent Documents 1-4).

JP 2008-301212 A Japanese Patent Laid-Open No. 06-053746 JP 59-072207 Utility Model Registration Gazette (Utility Model Registration No. 2524204)

  In recent years, in the audio output device, noise sound output from the audio output unit during the standby period becomes a problem, and therefore it is required to perform mute setting even during the standby period. For this reason, in an audio output device including a plurality of audio output units, it is necessary to keep a base current flowing even during a standby period, and thus power consumption increases, and target power consumption may not be achieved.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an audio output device capable of reducing power consumption in a standby period in an audio output device that attenuates an audio signal.

  In order to solve the above-mentioned problem, in the present invention, in an audio output device that attenuates an audio signal and performs a mute process, an attenuation circuit that sets an attenuation amount according to the value of an input base current, and the audio output device A power supply unit that supplies power for driving the power supply and reduces a supply amount of power during a standby period; a base current value is set according to the supply amount of power supplied by the power supply unit; and the attenuation circuit And a base current setting circuit for supplying the set base current.

  In the invention configured as described above, the attenuation circuit that sets the attenuation amount according to the value of the input base current and the power supply for driving the audio output device are supplied, and the power supply is supplied during the standby period. In a sound output device including a power supply unit that reduces the amount, the base current setting circuit sets a base current value according to the amount of power supplied by the power supply unit, and supplies the set base current to the attenuation circuit Therefore, the noise sound generated in the standby period can be attenuated with a small attenuation amount corresponding to the noise sound. Therefore, power consumption in the standby period can be reduced.

The power supply unit supplies a power source for driving the audio output device in a normal state and stops a power supply in a standby period, and generates a base current in a normal period and a standby period. The base current setting circuit normally supplies the base current by the power supplied from the first power supply unit and the second power supply unit. In the standby period, the base current may be supplied by the power supplied from the second power supply unit.
In the invention configured as described above, by switching the power supplied from the first and second power supply units, the amount of power supply in the standby period depends on the power supply amount of the second power supply unit. What is necessary is just to design, and the relationship between the power consumption and the attenuation amount during the standby period can be designed more easily.

The base current setting circuit may include a switch unit that stops power supply from the first power supply unit during the standby period.
In the invention configured as described above, the present invention can be realized by a simple configuration including the switch means.

  Furthermore, the supply amount of power by the first power supply unit may be larger than the supply amount of power by the second power supply unit.

  In addition, in order to provide a plurality of audio output units, when each audio output unit includes an attenuation circuit, if the power consumption of each attenuation circuit can be reduced, the power consumption of the entire audio output device is reduced. For this reason, a plurality of attenuation circuits may be mounted.

  Furthermore, as another example of the present invention, in a display device including a plurality of audio output modules that perform mute processing by attenuating an audio signal and a video output unit that outputs video based on the video signal, The audio output module supplies an attenuation circuit that sets an attenuation amount according to the value of the input base current and a power source for driving the audio output device, and reduces the supply amount of the power source during the standby period. 1 power supply unit, a second power supply unit that supplies less power than the first power supply unit during normal and standby periods, and a normal supply from the first power supply unit and the second power supply unit The base current is supplied by the power source to be switched, and during the standby period, switching is performed by the switch means so that the base current is supplied by the power source supplied from the second power source unit. A base current setting circuit may be configured to have a.

As described above, according to the present invention, the noise sound generated in the standby period can be attenuated with a small attenuation corresponding to the noise sound, and the power consumption in the standby period can be reduced.
According to the second aspect of the present invention, the relationship between the power consumption and the attenuation during the standby period can be designed more easily.
According to the third aspect of the present invention, the present invention can be realized with a simple configuration including the switch means.
Moreover, according to the invention concerning Claim 5, power consumption can be reduced more.

It is a block diagram explaining the structure of the audio | voice output apparatus concerning this invention. In the audio output device 10, it is a wave form diagram explaining the relationship between the fluctuation | variation of an input power supply, and a noise sound. It is a graph for demonstrating the relationship between the base current supplied to the attenuation circuit 30 as an example, and attenuation amount. 3 is a block diagram illustrating a display device 100. FIG. It is a block block diagram for demonstrating the structure of the audio | voice output module 10a. It is a block block diagram which shows the structure of the audio | voice output module 10a concerning 2nd Embodiment.

Embodiments of the present invention will be described below in the following order with reference to the drawings.
(1) Summary of the invention:
(2) First embodiment:
(3) Second embodiment:
(4) Other embodiments:

(1) Summary of the Invention FIG. 1 is a block diagram illustrating the configuration of an audio output device according to the present invention. As shown in FIG. 1, the audio output device 10 includes the following main parts. Reference numeral 20 denotes an amplifier that amplifies and outputs an input audio signal. Reference numeral 30 denotes an attenuation circuit, which attenuates an audio signal according to the value of the input base current. Reference numeral 40 denotes a power supply unit that supplies power for driving the audio output device 10 and varies in power supply amount in a standby state or the like. Reference numeral 50 denotes a speaker, which outputs the sound signal attenuated by the attenuation circuit 30 as sound. Reference numeral 60 denotes a base current setting circuit, which sets a base current according to fluctuations in the power supplied from the power supply unit 40 and supplies the base current to the attenuation circuit 30.

  FIG. 2 is a waveform diagram for explaining the relationship between the fluctuation of the input power supply and the noise sound in the audio output device 10. As shown in FIG. 2, the power supply from the power supply unit 40 includes a rising period from when the power is turned on until the predetermined voltage Vc1 is reached, a normal activation period for supplying power to the audio output device 10 at the predetermined voltage Vc1, and a standby signal. It consists of a falling period in which the predetermined voltage Vc1 falls to Vc2 in accordance with the input, and a standby period in which power is supplied at the voltage Vc2.

  When the audio output device 10 performs mute setting according to the mute signal, an attenuation amount of, for example, about 40 dB is required for the audio signal during the normal activation period. On the other hand, since the noise output is generated from the audio output unit in the standby period, the audio output device 10 needs to perform mute setting with a certain amount of attenuation during this period. Since the magnitude of noise in the standby period is smaller than the magnitude of the audio signal in the normal activation period, the attenuation amount in the mute setting can be made smaller than that in the normal activation period.

  FIG. 3 is a graph for explaining the relationship between the base current supplied to the attenuation circuit 30 as an example and the attenuation amount. In FIG. 3, the horizontal axis represents the base current value, and the vertical axis represents the attenuation (dB). Since the attenuation amount in the attenuation circuit 30 increases in proportion to the current value of the input base current, if the base current is supplied to the attenuation circuit 30 so as to obtain an optimum attenuation amount according to the magnitude of the audio signal, the consumption is increased. It becomes possible to reduce electric power.

  Therefore, in the present invention, during the normal startup period in which the power supply unit 40 supplies power, the base current setting circuit 60 sets the base current according to the voltage Vc1 supplied from the power supply unit 40 and supplies the power supply unit 40. When the power supply fluctuates, the base current is set according to the supplied power supply (for example, Vc2). Here, since the attenuation amount for attenuating the noise sound generated in the standby period may be a low value, a desired attenuation amount can be obtained even with the base current set by the fluctuating power source output from the power supply unit 40. Therefore, power consumption in the standby period can be reduced.

(2) First embodiment:
Hereinafter, a display device 100 having the function of the audio output device 10 will be described as an example of a first embodiment that embodies the audio output device according to the present invention with reference to the drawings. FIG. 4 is a block diagram illustrating the display device 100. The display device 100 includes the following main parts in addition to the parts shown in FIG. Reference numeral 99 denotes a front end unit that demodulates broadcast signals received by various antennas (not shown). Reference numeral 98 denotes a back-end unit that performs descrambling of demodulated data and decoding of compressed video / audio data. Reference numeral 97 denotes a display which displays a video based on the decoded video data. Reference numeral 96 denotes a main controller that controls driving of the display device 100.

  When the various antennas receive the carrier wave, the front end unit 99 modulates and extracts the broadcast signal superimposed on the carrier wave. The front end unit 99 includes a switching circuit that operates in response to a channel selection signal from the remote control device, and outputs a broadcast signal corresponding to a desired channel to the back end unit 98 by the switching circuit.

  The back-end unit 98 includes a demultiplexing unit that de-scrambles the data demodulated by the front-end unit 99 and decodes video / audio data compressed by the MPEG method. Furthermore, the back end unit 98 includes a video signal processing unit that performs signal processing on the decoded video data.

  The display 97 displays a video based on the video data decoded by the back end unit 98. In the present embodiment, the display 97 is a liquid crystal display, and outputs light by transmitting light from a backlight (not shown).

  The main controller 96 includes a CPU, a ROM, and a RAM, and controls the driving of the display device 100 by various programs stored in the ROM. Further, the main controller 96 outputs a mute signal for muting the output sound and a standby signal for shifting the display device 100 to the standby state in accordance with a command signal output from the remote control device or the like. Here, the standby state is to reduce the power consumption of the display device 100, and particularly in the present embodiment, the power consumption of the audio output module 10a (described later) is reduced.

  In addition, the display device 100 serves as an audio output device 10 that outputs an audio signal to an external device by connecting the R (right) and L (left) audio output module 10a to the external device via a jack. 10b and 10c. Since the audio output module 10a and the output terminals 10b and 10c have the same configuration, the following description is based on the audio output module 10a.

FIG. 5 is a block diagram for explaining the configuration of the audio output module 10a. The audio output module 10a embodies the audio output device 10 shown in FIG. 1 and has the following configuration.
The attenuation circuit 30 includes a transistor Q5 and a resistor R4, and the amount of attenuation is set according to the value of the base current supplied to the base of the transistor Q5. The power supply unit 40 includes a first power supply unit 40a for driving the audio output module 10a during the normal startup period, and a second power supply unit 40b for supplying a base current during the standby period. Here, the first power supply unit 40a supplies 9V power, and the second power supply unit 40b supplies 3.3V power.

  The first power supply unit 40a is connected to the main controller 96. When a standby signal is output from the main controller 96, the first power supply unit 40a shifts to a standby period in which the supply of power is stopped. The base current setting circuit 60 is connected to the main controller 96 and switches the value of the base current supplied to the attenuation circuit 30 according to the mute signal output from the main controller 96.

=== Configuration of Base Current Setting Circuit 60 ===
Hereinafter, a specific configuration of the base current setting circuit 60 will be described. The base current setting 60 is a first base current setting in which the base current is set by the power supplied from the first power supply unit 40a during the normal startup period, is supplied to the attenuation circuit 30, and is stopped from being supplied during the standby period. Unit 60a, and a second base current setting unit 60b that sets the base current by the power supplied from the second power supply unit 40b during the normal start-up period and the standby period and supplies the base current to the attenuation circuit 30. Yes. Therefore, the sum of the base currents supplied from the first base current setting unit 60a and the second base current setting unit 60b is supplied to the attenuation circuit 30 in the normal startup period of the audio output module 10a. In the standby period, only the base current set by the second base current setting unit 60 b is supplied to the attenuation circuit 30.

  The first base current setting unit 60a includes the following main parts. The transistor Q1 switches power supply from the first power supply unit 40a by self-bias through the resistor R1. The transistor Q3 and the resistor R7 set a base current from the power supply supplied from the first power supply unit 40a according to the mute signal supplied to the base of the transistor Q3 via the resistor R9. The emitter of the transistor Q1 is connected to the collector of the transistor Q3 and is grounded through the resistor R3. The resistor R1 is connected to the base of the transistor Q1 and the collector of the transistor Q2 (described later) of the second base current setting unit 60b via a diode D1. Furthermore, the output side of the resistor R7 is connected to the base of the transistor Q5 of the attenuation circuit 30, and supplies the base current set by the transistor Q3 and the resistor R7 to the attenuation circuit 30.

  The second base current setting unit 60b includes the following main parts. When a mute signal is input to the base of the transistor Q2 via the resistor R8, the transistor Q2 and the resistor R6 set a base current according to the amount of power supplied from the power supply unit 40. The output side of the resistor R6 is grounded via the resistor R2 and is connected to the base of the transistor Q5 of the attenuation circuit 30.

  Note that the power supplied from the first power supply unit 40a and the second power supply unit 40b is switched by the first and second base current setting units, respectively. The power supply amount of the power supply unit 40b may be set, and the relationship between power consumption and attenuation during the standby period can be designed more easily.

=== Action of Audio Output Module ===
Hereinafter, the operation of the audio output module 10a according to the present embodiment will be described. First, the mute setting in the normal activation period will be described. When the main power supply of the display device 100 is turned on, the main controller 96 turns on the first power supply unit 40 a and the second power supply unit 40 b and supplies power to the amplifier 20. Therefore, the input signal is amplified by the amplifier 20, passes through the attenuation circuit 30, and is output from the output terminal 10b to the speaker 50.

  In the above state, when a mute signal is input from the main controller 96 via the resistor R9, the transistor Q3 and the resistor R7 of the first base current setting unit 60a correspond to the power supplied from the first power supply unit 40a. A base current is set and supplied to the base of the transistor Q5 of the attenuation circuit 30. Similarly, when a mute signal is input from the main controller 96 via the resistor R8, the transistor Q2 and the resistor R6 of the second base current setting unit 60b are supplied from the first power supply unit 40a and the second power supply unit 40b. The base current is set according to the power source to be supplied and supplied to the base of the transistor Q5 of the attenuation circuit 30. Therefore, the combined current of the base currents set by the first power supply unit 40a and the second power supply unit 40b is supplied to the transistor Q5 of the attenuation circuit 30.

  Next, the mute setting of the audio output module 10a during the standby period will be described. When a standby signal is output from the main controller 96 to the audio output module 10a, the first power supply unit 40a stops supplying power to the audio output module 10a. In this state, when a mute signal is output from the main controller 96 via the resistor R8, the transistor Q2 and the resistor R6 of the second base current setting unit 60b are in accordance with the power supplied from the second power supply unit 40b. The base current is set, and the base current is supplied to the base of the transistor Q5 of the attenuation circuit 30. Here, in the standby period, an audio signal is not input from the amplifier 20, and only the noise sound shown in FIG. 2 needs to be set to mute, so that a desired attenuation amount can be lower than that in the normal activation period. Therefore, it is possible to obtain a desired attenuation amount only with the base current based on the power supplied from the second power supply unit 40b.

  As described above, in the present invention, since the value of the base current supplied to the attenuation circuit 30 is changed in accordance with the fluctuation of the power supplied from the power supply unit 40, the noise sound generated during the standby period or the like is attenuated low. It is possible to attenuate by the amount, and the balance between the desired attenuation and power consumption can be optimized. Further, in an apparatus including a plurality of audio output units, power consumption in each audio output unit can be reduced, so that an apparatus with low power consumption in the standby period can be provided.

(3) Second embodiment:
Further, since the base current setting circuit 60 may be configured to vary the supply amount of the base current according to the fluctuation of the power supplied from the power supply unit 40, the base current setting circuit 60 is configured by the switching element shown in the first embodiment. It is not limited. FIG. 6 is a block configuration diagram showing the configuration of the audio output module 10a according to the second embodiment. In the audio output module 10a shown in FIG. 6, the base current setting circuit 60 includes a first base current setting unit 60a and a second base current setting unit 60b configured by a plurality of resistors, and includes the first power supply unit 40a and the first power supply unit 40a. The second power supply unit 40b and the transistor of the attenuation circuit 30 are connected.

  In the base current setting circuit 60 according to the second embodiment, during the normal startup period, the supply amount of power supplied from the first power supply unit 40a and the second power supply unit 40b is linear according to the input of the mute signal. Is set and supplied to the attenuation circuit 30. On the other hand, in the standby period, the power supply of the first power supply unit 40a is reduced (stopped), so that the second power supply unit 40b (including the first power supply unit 40a is included depending on the period) according to the input of the mute signal. B) A base current corresponding to the power supply is supplied to the attenuation circuit 30. As in the first embodiment, it is assumed that the base current based on the power supplied from the second power supply unit 40b does not vary during the normal startup period and the standby period. In the second embodiment, since the base current setting circuit 60 does not use a switching element, a simpler circuit configuration can be achieved. The display device according to the second embodiment has been described above.

(4) Other embodiments:
There are various embodiments of the present invention. The display device described in each embodiment is an example, and the display device is not limited to the display device as long as the product has the function of the audio output device.

  In addition, the configuration of the base current setting circuit shown in each embodiment is an example, and various configurations can be applied as long as they exhibit the same function.

Needless to say, the present invention is not limited to the above embodiments. It goes without saying for those skilled in the art,
・ Applying mutually interchangeable members and configurations disclosed in the above embodiments by appropriately changing the combination thereof.− Although not disclosed in the above embodiments, it is a publicly known technique and the above embodiments. The members and configurations that can be mutually replaced with the members and configurations disclosed in the above are appropriately replaced, and the combination is changed and applied. It is an embodiment of the present invention that a person skilled in the art can appropriately replace the members and configurations that can be assumed as substitutes for the members and configurations disclosed in the above-described embodiments, and change the combinations and apply them. It is disclosed as.

  DESCRIPTION OF SYMBOLS 10 ... Audio | voice output apparatus, 10a ... Audio | voice output module, 10b, 10c ... Output terminal, 20 ... Amplifier, 30 ... Attenuation circuit, 40 ... Power supply part, 40a ... 1st power supply part, 40b ... 2nd power supply part, 50 ... Speaker, 60 ... Base current setting circuit, 60a ... First base current setting section, 60b ... Second base current setting section, 96 ... Main controller, 97 ... Display, 98 ... Back end section, 99 ... Front end section, 100 ... Display device

Claims (6)

In an audio output device that performs mute processing by attenuating an audio signal,
An attenuation circuit that sets an attenuation amount according to the value of the input base current;
A power supply unit that supplies power for driving the audio output device and reduces the amount of power supply during the standby period;
An audio output comprising: a base current setting circuit that sets a value of a base current according to a supply amount of power supplied from the power supply unit and supplies the set base current to the attenuation circuit; apparatus. The power supply section supplies a power supply for driving the audio output device at a normal time, a first power supply section for stopping the power supply during a standby period, and a second power supply for supplying a power supply at a normal time and a standby period A power supply unit,
The base current setting circuit normally supplies a base current from power supplied from the first power supply unit and the second power supply unit, and is supplied from the second power supply unit during a standby period. The audio output device according to claim 1, wherein the base current is supplied by a power source.   3. The audio output device according to claim 2, wherein the base current setting circuit includes switch means for stopping power supply from the first power supply unit during the standby period.   4. The audio output device according to claim 2, wherein a supply amount of power by the first power supply unit is larger than a supply amount of power by the second power supply unit. 5. .   The audio output device according to any one of claims 1 to 4, wherein a plurality of the attenuation circuits are mounted. In a display device comprising: a plurality of audio output modules for attenuating audio signals and performing mute processing; and a video output unit for outputting video based on the video signals.
The plurality of audio output modules are:
An attenuation circuit that sets an attenuation amount according to the value of the input base current;
A first power supply unit that supplies power for driving the audio output device and reduces the amount of power supply during a standby period;
A second power supply that supplies less power than the first power supply during normal and standby periods;
In normal times, the base current is supplied by the power supplied from the first power supply unit and the second power supply unit, and during the standby period, the base current is supplied by the power supply supplied from the second power supply unit. And a base current setting circuit that performs switching by means of switch means.

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