JP4483894B2 - Video / audio playback device - Google Patents

Description

  The present invention relates to a video / audio reproduction device that reproduces and outputs video and audio, and more particularly to a video / audio reproduction device having a display with a backlight.

  Some video / audio playback devices, such as tuners that receive broadcast signals and players that read and play content from a recording medium such as a DVD, are integrated with a display that plays back and outputs video and a speaker that plays back and outputs audio. Something that is also provided. In the video / audio reproduction device integrated with the display and the speaker, since the power supplied to the display is large, the power supply to the display should be stopped during standby to reduce the power consumption. Has been proposed (see Patent Document 1 and Patent Document 2).

  In the backlight automatic control device of Patent Document 1, ON / OFF of the backlight of the liquid crystal monitor is controlled based on the presence / absence of reception of a television broadcast signal to reduce power consumption. The electronic device disclosed in Patent Document 2 groups a plurality of power saving functions including power saving of a backlight of a liquid crystal display (LCD), and manages the power saving functions collectively for each group. .

Furthermore, by providing an inverter protection circuit, an LCD display device is proposed in which an abnormality of the fluorescent tube backlight is detected to cut off the power supply to the inverter circuit, and the microcomputer performs a protection operation based on the abnormality detection. (See Patent Document 3). In this LCD display device, the inverter protection circuit detects an abnormality of the fluorescent tube backlight when the tube current of the fluorescent tube backlight exceeds the normal upper limit or falls below the normal lower limit. That is, in the inverter protection circuit, when the tube current of the fluorescent tube backlight exceeds the normal upper limit, the inverter circuit is protected against overpower, and when the tube current of the fluorescent tube backlight falls below the normal lower limit, the inverter circuit Protects against power loss.
JP-A-3-24875 JP 2006-254185 A Utility Model Registration No. 319100

  However, when the inverter protection circuit in Patent Document 3 is provided in an electronic device having the power saving function of the backlight as in Patent Document 1 and Patent Document 2, the tube current of the backlight is reduced by the power saving function of the backlight described above. In order to detect the reduction, the inverter circuit is protected against power reduction and a protection operation is executed. Therefore, for example, when playback of video is not necessary for playback of content only by sound, the backlight of the LCD with high power consumption is put into a standby state by the power saving function. At this time, it is detected that the tube current of the backlight has decreased, and the protection operation is executed, so that the entire apparatus enters a standby state.

  In view of such a problem, an object of the present invention is to provide a video / audio reproduction device in which execution of a protect operation is prohibited when power supply to a display is stopped by a power saving function.

  In order to achieve the above object, a video / audio reproduction device of the present invention includes a video output circuit that performs signal processing on a video signal obtained from content, and performs signal processing on the audio signal obtained from the content. An audio output circuit that performs, a display that reproduces and outputs video based on the video signal processed by the video output circuit, a speaker that reproduces and outputs audio based on the audio signal processed by the audio output circuit, and each of the devices in the apparatus In a video / audio reproduction device including a control circuit that controls a circuit and a power supply circuit that supplies power to each circuit in the device, when power is not displayed on the display, power is supplied from the power supply circuit to the display The control circuit detects that the output voltage of the power supply circuit to the display is lower than a predetermined voltage, and Characterized by disabling the under voltage protection function for operating protection of each circuit of the inner.

In the video / audio reproduction device configured as described above, when only the audio signal is acquired from the content, the power supply to the display may be stopped and the reduced voltage protection function may be invalidated. An operation unit for instructing each operation of the apparatus, and when the stop of power supply to the display is instructed through the operation unit, the power supply to the display is stopped and the reduced voltage protection function is disabled. It does n’t matter what you do.

Further, the display is a liquid crystal display device provided with a backlight, and includes an inverter circuit that supplies current to the backlight by electric power supplied from the power supply circuit, and the control circuit outputs an output voltage from the inverter circuit. It is also possible to execute the reduced voltage protection function by monitoring the above.

  According to the present invention, when power supply to a display that consumes a large amount of power is stopped to reduce power consumption, the reduced voltage protection function based on the output voltage to the display can be disabled. Thereby, when the display is stopped, it is possible to prevent a protective operation from acting on a circuit portion other than the display by the reduced voltage protection function and stopping the operation. Therefore, in the video / audio reproduction device, it is possible to achieve both the power supply stop of the display for reducing power consumption and the reduced voltage protection function.

  Embodiments of the present invention will be described with reference to the drawings. As an example of the video / audio playback device of the present embodiment, a video / audio playback device including a tuner circuit will be described as an example. However, video content and audio content recorded on a recording medium such as a DVD or a hard disk can be played back. It may be a video / audio reproduction device. FIG. 1 is a block diagram showing an internal configuration of a video / audio reproduction device according to this embodiment.

  1 includes an AC / DC converter 1 that converts an AC voltage supplied from a commercial power source into a DC voltage, and power supply circuits 2a and 2b that are supplied with a DC voltage from the AC / DC converter 1. The microcomputer 3 that controls the operation of each block in the apparatus, the tuner circuit 4 that receives the broadcast signal, the audio output circuit 5 that decodes the audio signal acquired by the tuner circuit 4, and the audio output circuit 5 A speaker 6 that reproduces and outputs audio based on the received audio signal, a video output circuit 7 that performs decoding and signal processing of the video signal acquired by the tuner circuit 4, and an image based on the video signal from the video output circuit 7. LCD 8 for reproduction display, inverter circuit 9 for supplying a tube current to the fluorescent tube backlight 8a of LCD 8, an operation unit 10 operated by a user to give an instruction, Provided.

  The power supply circuit 2a converts the DC voltage from the AC / DC converter 1 into a DC voltage having a desired voltage value, and supplies it to the microcomputer 3, the tuner circuit 4, the audio output circuit 5, and the video output circuit 7, respectively. Further, the power supply circuit 2b converts the DC voltage from the AC / DC converter 1 into a DC voltage having a desired voltage value, and supplies it to the LCD 8 and the inverter circuit 9, respectively. Further, the microcomputer 3 monitors the voltage value supplied from the inverter circuit 9 to the fluorescent tube backlight 8a of the LCD 8, and protects the device by overpowering and reducing power in the inverter circuit 9.

  In the video / audio reproduction device having such a configuration, the broadcast signal selected by the tuner circuit 4 is demodulated and then decoded to obtain the content of the desired channel. At this time, when the content by the broadcast signal received by the tuner circuit 4 is a moving image content, a video signal and an audio signal are acquired, and the obtained audio signal and video signal are respectively sent to the audio output circuit 5 and the video output circuit 7. Given. When the content by the broadcast signal received by the tuner circuit 4 is an audio content, the audio signal is acquired and the obtained audio signal is given to each audio output circuit 5.

  Further, when the audio signal is decoded and converted into an analog audio signal by the audio output circuit 5, the analog audio signal is supplied to the speaker 6, so that the audio is reproduced and output from the speaker 6. When the video signal is decoded by the video output circuit 5, the decoded video signal is given to a driver (not shown) of the LCD 8 so that the video is reproduced and output from the LCD 8. At this time, since the fluorescent tube backlight 8a emits light when a tube current is supplied from the inverter circuit 9, it is possible to reproduce and output a clear image from the LCD 8.

  In such a video / audio reproduction device, when a broadcast signal based on video content is received by the tuner circuit 4, the power supply circuit 2 b is turned on by the microcomputer 3 to supply power to the LCD 8 and the inverter circuit 9. The As described above, when the microcomputer 3 monitors the output voltage from the inverter circuit 9 and the output voltage from the inverter circuit 9 becomes an overvoltage or a reduced voltage, the power supply circuit 2b is turned OFF, and other circuits Protection for the block is provided by the microcomputer 3. In particular, when a reduced voltage is detected, a voltage value supplied to another circuit block may fluctuate due to a load change, so that the microcomputer 3 protects the other circuit block.

  Further, when a broadcast signal based on audio content is received by the tuner circuit 4, video reproduction output is not performed. Therefore, the power supply circuit 2 b is turned off by the microcomputer 3, and power is supplied to the LCD 8 and the inverter circuit 9. Stopped. At this time, since there is no power supply to the inverter circuit 9, the output voltage from the inverter circuit 9 becomes low. Therefore, when the voltage drop protection function by the microcomputer 3 is effective, the output voltage from the inverter circuit 9 is low, so that the microcomputer 3 protects other circuit blocks. For this reason, it is assumed that the reduced voltage protection function by the microcomputer 3 is invalid and the output voltage from the inverter circuit 9 is not detected.

  A flowchart showing the operation of such a video / audio reproduction apparatus is shown in FIG. Hereinafter, the operation of the video / audio reproduction device will be described with reference to the flowchart of FIG.

  When the operation unit 10 is operated and the power supply of the video / audio reproduction device is turned on, the AC voltage supplied from the commercial power supply is converted into a DC voltage by the AC / DC converter 1, and is supplied to the power supply circuits 2a and 2b. (STEP 1). Then, the tuner circuit 4 performs a channel selection operation for the set channel, and performs a reception operation for the broadcast signal of the set channel (STEP 2).

  Thereafter, it is confirmed by the microcomputer 3 whether or not the video signal is acquired from the broadcast signal received by the tuner circuit 4 (STEP 3). At this time, if acquisition of the video signal is confirmed (Yes in SETP3), it is next confirmed by the microcomputer 3 whether the display function by the LCD 8 is instructed to be ON by the operation unit 10 (STEP 4). If the display function of the LCD 8 is instructed to be ON (YES in STEP 4), first, the microcomputer 3 sets the power circuit 2b to ON and supplies power to the LCD 8 and the inverter circuit 9 (STEP 5). . Next, in the microcomputer 3, the reduced voltage protection function based on the monitoring of the output voltage from the inverter circuit 9 is validated (STEP 6).

  On the other hand, when the video signal is not acquired from the received broadcast signal (No in STEP 3), or when the display function by the LCD 8 is turned off by the operation unit 10 (No in STEP 4), the microcomputer 3 The reduced voltage protection function based on the monitoring of the output voltage from the circuit 9 is invalidated (STEP 7). Thereafter, the microcomputer 3 sets the power supply circuit 2b to the OFF state, and stops the power supply to the LCD 8 and the inverter circuit 9 (STEP 8).

  When operating in this way, in STEP5, when the power supply circuit 2b is already in the ON state, the power supply circuit 2b is kept in the ON state, and when the power supply circuit 2b is in the OFF state, it is switched to the ON state. Similarly, in STEP 8, when the power supply circuit 2b is already in the OFF state, the power supply circuit 2b is kept in the OFF state, and when the power supply circuit 2b is in the ON state, the state is switched to the OFF state.

  In STEP6, when the microcomputer 3 has already set the reduced voltage protection function to the enabled state, it remains in the enabled state, and when the reduced voltage protection function has been set to the disabled state, it is enabled. Switch to state. Similarly, in STEP7, when the reduced voltage protection function is already set to the invalid state in the microcomputer 3, it remains in the invalid state, and when the reduced voltage protection function is set to the valid state, it is invalid. Switch to the state.

  When the reduced voltage protection function is validated in STEP 6 or when the power supply circuit 2b is turned off in STEP 8, the microcomputer 3 determines whether or not the power of the video / audio reproduction device is turned off by the operation unit 10. Confirm (STEP 9). At this time, if the operation unit 10 has not instructed to turn off the power of the video / audio reproduction device (No in STEP 9), then the microcomputer determines whether the channel to be selected by the tuner circuit 4 has been switched by the operation unit 10 or not. 3 (STEP 10).

  When switching of the channel to be selected is instructed by the tuner circuit 4 (YES in STEP 10), the process proceeds to STEP 2, the channel frequency to be selected by the tuner circuit 4 is switched, and the broadcast signal reception operation of the new channel is performed. Is done. On the other hand, when the tuner circuit 4 is not instructed to switch the channel to be selected (No in STEP 10), the process proceeds to STEP 3 with the broadcast signal of the same channel being received by the tuner circuit 4. Further, when it is confirmed in STEP 9 that the power-off of the video / audio reproduction device is instructed (Yes), the power of the video / audio reproduction device is turned off and the power supply to the AC / DC converter 1 is stopped. Thus, the operation of the entire apparatus is stopped (STEP 11).

  When the power is turned off in STEP 11, the state of the device (such as the channel frequency being selected) when the power is turned off is stored by the microcomputer 3, and then when the power is turned on in STEP 1, the microcomputer The video / audio reproduction device operates in accordance with the operation state stored in 3. In this way, when the audio / video playback device is turned on, each block may be operated depending on the operation state when the power was turned off the last time, or after resetting to the previously stored initial state. Each block may be operated.

  The present invention can be applied to a video / audio reproduction device including a tuner circuit capable of receiving various broadcasts such as terrestrial digital / analog broadcasts and satellite digital / analog broadcasts. Further, the present invention can be applied to a video / audio reproduction device that reproduces audio contents and moving image contents stored in various storage media such as a video cassette recorder, CD, MD, DVD, hard disk, and memory.

These are block diagrams which show the internal structure of the audio-video reproduction apparatus in embodiment of this invention. These are the flowcharts which show the operation | movement of the audio-video reproduction apparatus of FIG.

Explanation of symbols

1 AC / DC converter 2a, 2b Power supply circuit 3 Microcomputer 4 Tuner circuit 5 Audio output circuit 6 Speaker 7 Video output circuit 8 LCD
9 Inverter circuit 10 Operation section

Claims (4)

A video output circuit that performs signal processing on a video signal obtained from content, an audio output circuit that performs signal processing on an audio signal obtained from the content, and a video signal processed by the video output circuit A display that reproduces and outputs video based thereon, a speaker that reproduces and outputs audio based on the audio signal processed by the audio output circuit, a control circuit that controls each circuit in the device, and power supply to each circuit in the device A video / audio reproduction device comprising:
When display by the display is not made,
While stopping the power supply from the power supply circuit to the display,
In the control circuit, the video / audio is disabled by detecting that the output voltage of the power supply circuit to the display is lower than a predetermined voltage and protecting the operation of each circuit in the apparatus. Playback device.   The video / audio reproduction device according to claim 1, wherein when only an audio signal is acquired from the content, power supply to the display is stopped and the reduced voltage protection function is disabled. Provided with an operation unit that instructs each operation of the device
When instructed to stop power supply to the display through the operation unit,
The video / audio reproduction device according to claim 1 or 2, wherein power supply to the display is stopped and the reduced voltage protection function is disabled. The display is a liquid crystal display device provided with a backlight;
Comprising an inverter circuit for supplying current to the backlight by power supplied from the power supply circuit;
4. The video / audio reproduction device according to claim 1, wherein the control circuit executes the reduced voltage protection function by monitoring an output voltage from the inverter circuit. 5.

Images