JP2007194881A - Liquid crystal display device and liquid crystal television - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device and a liquid crystal television whose standby electric power become stable even immediately after an external power source is turned on. <P>SOLUTION: The liquid crystal display device and the liquid crystal television can switch and make effective on-setting for displaying video on a screen and standby setting for displaying no video on the screen reduced in power consumption more than the on-setting. The whole devices except back lights are placed in a mode of the on-setting for a predetermined time immediately after the external power source starts to supply electric power, and then made to operate in a mode of the standby setting. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device and a liquid crystal television equipped with a power supply circuit that converts an input voltage on the primary side into a desired voltage via a transformer and outputs the voltage on the secondary side.

  Normally, in a liquid crystal display device such as a liquid crystal television, an off setting in which power is not supplied from an external power source, an on setting in which power is supplied from the external power source and an image is displayed on the screen, and power supply from the external power source are saved. A standby setting for waiting for a user operation input with power.

  By the way, it is recommended that the standby power of the liquid crystal television be 1 W or less by Energy Star, which is a power saving program for electrical equipment. In order to reduce standby power, various approaches are conceivable. As one of them, the drive current of the power transformer must be reduced as much as possible.

In Patent Document 1, when a control signal for switching to a standby operation is input from a microcomputer, a power supply oscillation stop circuit acts on a control terminal of a controller of a power supply to oscillate a switch element that supplies a pulse to a transformer for a certain period. There is disclosed a power supply circuit for a television receiver that is stopped and a switch circuit cuts off the supply of voltage to a small signal circuit by a control signal.
JP-A-10-210388

  However, in a standby state immediately after power is supplied from the external power supply, the load on the power supply circuit is almost only the microcomputer. In general, a switching power supply is used for the power supply circuit. However, if the load applied to the power supply circuit is only a microcomputer, the load applied to the power supply circuit is small, and the load is not stable due to variations in the leakage inductance of the transformer. Then, feedback is applied to the power supply circuit, and the drive voltage is lowered. Therefore, it takes more time for stable oscillation than when shifting from the on setting to the standby setting, and the standby power is increased by 0.1 to 0.15 W in the standby setting for 30 seconds to 1 minute immediately after the power is turned on. There was a problem of becoming.

Also, in recent years, in order to save power, when the user is not viewing, the external power supply is unplugged or the main switch is turned off. There is a tendency for users to increase. In such a usage method, it is possible that the standby power immediately after the external power supply is turned on every time viewing is performed, and the standby power described in the catalog may not match the actual standby power.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a liquid crystal display device and a liquid crystal television in which standby power is stable even immediately after external power is turned on.

In order to solve the above-mentioned problems, in the invention according to claim 1 of the present invention, a liquid crystal panel that displays an image on a screen, a backlight that illuminates the liquid crystal panel from behind, and a television broadcast signal received by an antenna. A tuner circuit that extracts and outputs a television broadcast signal of a channel selected from the above, a video processing unit that displays an image on the liquid crystal panel based on the television broadcast signal output by the tuner circuit, and the backlight In a liquid crystal television comprising: an inverter circuit that supplies power to a speaker; a speaker that outputs sound; and a sound processing unit that outputs sound to the speaker; and a rectifier circuit that converts input alternating current into direct current and outputs the converted alternating current A primary side to which direct current is input from the rectifier circuit and a secondary side that outputs direct current induced on the primary side. A power supply circuit comprising: a switching transformer formed; an oscillation circuit that performs PWM control of the primary side based on a signal fed back according to the load on the secondary side; and an on setting that displays an image on the screen. , A microcomputer that switches between a standby setting that consumes less power than the on setting without displaying video on the screen, and an operation input that instructs the microcomputer to switch between the on setting and the standby setting And when the power supply from the external power supply to the power supply circuit is started, the direct current rectified and smoothed by the rectifier circuit is supplied to the primary side of the switching transformer, and the power supply is supplied from the secondary side. The power supply circuit starts supplying power to the microcomputer, and the microcomputer starts the liquid crystal panel, the tuner circuit, the video processing unit, and the audio. When the logic unit is operated with the on setting, the power supply circuit starts to supply power to the liquid crystal panel, the tuner circuit, the video processing unit, and the audio processing unit, and the microcomputer When a predetermined time elapses from the start of power supply to the panel, the tuner circuit, the video processing unit, and the audio processing unit, the standby setting is executed, and the power supply circuit sets the drive voltage of the switching transformer in the standby setting. The structure is stable and intermittently performs the primary side oscillation.
In the invention according to claim 1 configured as described above, when power is supplied from an external power source to the power supply circuit, power is first supplied to the microcomputer. Then, the microcomputer operates the liquid crystal panel, the tuner circuit, the video processing unit, and the audio processing unit with the on setting, and executes the standby setting after a predetermined time has elapsed.

In order to achieve the above object, in the liquid crystal display device according to claim 2, a liquid crystal panel that displays an image on a screen, a backlight that irradiates the liquid crystal panel from behind, and an image that is displayed on the screen. On-off setting and switching execution means for switching and executing the on-setting and the standby setting that consumes less power than the on-setting without displaying video on the screen, power supply from an external power supply is started In the liquid crystal display device activated by the standby setting, immediately after the power supply from the external power supply is started, the liquid crystal display device except the backlight is set to the on setting for a predetermined time, and then the standby setting and It is as composition to do.
In the invention according to claim 2 configured as described above, when power is started to be supplied to the liquid crystal display device, the entire device except for the backlight is in the same state as the ON setting for a predetermined time, and after the predetermined time has elapsed. Set to standby.

The invention according to claim 3 is the liquid crystal display device according to claim 2, further comprising a power supply circuit that converts the input voltage on the primary side to a desired voltage via a transformer and outputs the voltage on the secondary side, The power supply circuit is configured to control the primary-side oscillation in accordance with the secondary-side load, and intermittently perform the primary-side oscillation in the standby setting.
In the invention according to claim 3 configured as described above, the power supply circuit converts the input voltage on the primary side into a desired voltage via a transformer and outputs it to the secondary side, and also to the load on the secondary side. Accordingly, the oscillation on the primary side is controlled so that a desired voltage is output to the secondary side. In the standby setting, the primary side oscillation is intermittently performed to reduce power consumption.

Furthermore, in the invention according to claim 4, in the liquid crystal display device according to claim 2 or claim 3, the power supply circuit converts the input alternating current into direct current and outputs the output, and the rectification A switching transformer composed of a primary side to which direct current is input from a circuit and a secondary side that outputs direct current induced on the primary side, and PWM for the primary side based on a signal fed back from the secondary side And an oscillation circuit to be controlled.
In the invention according to claim 4 configured as described above, the rectifier circuit converts an input alternating current into a direct current and outputs the direct current to the switching transformer, and the switching transformer receives the primary from the rectifier circuit. DC is output to the secondary side and the oscillating circuit performs PWM control on the primary side based on a signal fed back from the secondary side.

Furthermore, the invention according to claim 5 is the liquid crystal display device according to any one of claims 2 to 4, wherein an inverter circuit that supplies power to the backlight, a speaker that outputs sound, and an antenna are provided. A tuner circuit that extracts and outputs a television broadcast signal of a selected channel from a received television broadcast signal, and an image that displays an image on the liquid crystal panel based on the television broadcast signal output by the tuner circuit A processing unit and an audio processing unit that outputs audio to the speaker based on a television broadcast signal output from the tuner circuit, and immediately after power supply from an external power source is started, the liquid crystal panel and the After the inverter circuit, the tuner circuit, the video processing unit, and the audio processing unit are turned on for a predetermined time, There is a configuration in which a standby setting.
In the invention according to claim 5 configured as described above, the tuner circuit extracts and outputs a television broadcast signal of a selected channel from a television broadcast signal received by an antenna, and the video processing unit An image is displayed on the liquid crystal panel based on the television broadcast signal output from the tuner circuit. The sound processing unit causes the speaker to output sound based on the sound signal extracted and output from the tuner circuit. When power is supplied to the liquid crystal display device, power is supplied to the liquid crystal panel, the inverter circuit, the tuner circuit, the video processing unit, and the audio processing unit for a predetermined time, and the video is A load for the power supply circuit is obtained by performing a process for displaying on the liquid crystal panel. At this time, no power is supplied to the backlight and the backlight is not operated, so that no video is displayed on the screen.

  As described above, according to the invention of claim 2 of the present invention, it is possible to provide a liquid crystal display device that can immediately stabilize the power supply when the standby setting is executed even immediately after the start of the supply of the external power supply. Can do.

According to the third aspect of the invention, it is possible to further stabilize the power consumption when executing the standby setting and reduce the power consumption.
According to the fourth aspect of the invention, it is possible to further stabilize the power consumption when executing the standby setting and reduce the power consumption.
Furthermore, according to the fifth aspect of the invention, it is possible to further stabilize the power consumption when executing the standby setting and reduce the power consumption.
Furthermore, it is needless to say that in a more specific configuration as in claim 1, the same effects as those of the inventions of claims 2 to 5 described above are exhibited.

Hereinafter, embodiments of the present invention will be described in the following order.
(1) Configuration of LCD television:
(2) Operation of power supply circuit in pseudo P-ON:
(3) Summary:

(1) Configuration of LCD television:
Hereinafter, a liquid crystal television 10 according to an embodiment of the present invention will be described.

  FIG. 1 is a block diagram showing a schematic configuration of a liquid crystal television 10 according to an embodiment of the present invention. The liquid crystal television 10 generally includes a tuner circuit 15 to which an antenna 15a is connected, an image data generation circuit 20, a panel drive circuit 25, a liquid crystal module 30, a power supply circuit 35, a microcomputer 40, an inverter circuit 45, and the like. The voice processing unit 50 and the remote control light receiving unit 55 that receives an operation command transmitted from the remote control 56 are included. As described above, the remote controller 56 constitutes the operation input means that receives an operation input from the user.

  The microcomputer 40 controls power on / standby switching, channel switching, volume up / down, and the like in accordance with control commands received by the remote control light receiving unit 55. In the above configuration, the microcomputer 40 is electrically connected to each part constituting the liquid crystal television 10, and a CPU as a component within the microcomputer 40 is written in a ROM, a RAM, or the like that is also a component within the microcomputer 40. The entire liquid crystal television 10 is controlled according to each program. The CPU, ROM, and RAM are not shown.

  The tuner circuit 15 receives a television broadcast signal from the antenna 15a under the control of the microcomputer 40, extracts a video signal or an audio signal as an intermediate frequency signal from the television broadcast signal while performing predetermined signal amplification processing, and the like. The video signal is output to the image data generation circuit 20. The image data generation circuit 20 converts the input video signal into a digital signal according to the signal level, and performs a matrix conversion process based on the luminance signal and the color difference signal extracted from the video signal, and performs RGB conversion as image data. (Red, Green, Blue) signal is generated. The audio signal is output to a speaker (not shown) through the audio processing unit 50.

  In the panel drive circuit 25, the RGB signal is input, and the RGB signal is subjected to scaling processing in accordance with the number of pixels of the liquid crystal module 30 (aspect ratio, m: n), and one screen to be displayed on the liquid crystal module 30. Image data is generated. Then, by outputting the image data generated in this way to the liquid crystal module 30, the liquid crystal module 30 displays an image based on the image data. As described above, the image data generation circuit 20 and the panel drive circuit 25 constitute the video processing unit.

  The liquid crystal module 30 includes a liquid crystal panel 30a, a backlight 30b, and a control circuit 30c. The control circuit 30c is an electronic circuit that performs screen display control drive processing, and generates voltage for driving the R liquid crystal panel, the G liquid crystal panel, and the B liquid crystal panel for each color from the image data output from the panel drive circuit 25. To do. The backlight 30b is turned on when a high voltage is supplied from the inverter circuit 45, and the generated light is irradiated from the back surface of the liquid crystal panel 30a and transmitted through the liquid crystal panels of the respective colors in the front direction. Thereby, the liquid crystal module 30 displays a video corresponding to the image data from the screen, that is, a video corresponding to the video signal.

The power supply circuit 35 is supplied with a power supply voltage (AC) from an external power supply 36 (commercial power supply or the like), and supplies the supplied power supply voltage to each circuit such as the microcomputer 40 and the inverter circuit 45. The power supply circuit 35 converts the voltage supplied to each circuit from AC to DC as necessary.
The inverter circuit 45 converts the DC voltage supplied from the power supply circuit 35 into an AC voltage, supplies the AC voltage as a drive signal to the backlight 30b, and turns on the backlight 30b.

  FIG. 2 is a block diagram showing a schematic configuration related to power supply. The power supply circuit 35 is a switching power supply that generally includes a rectifier circuit 35a, a switching transformer 35b, a feedback circuit 35c, and an oscillation circuit 35d. The direct current output from the switching transformer 35b is supplied to each unit 40, 20, 50, 25, 45, 30c, 30a and the like.

The rectifier circuit 35a is composed of a rectifier diode, a smoothing capacitor, and the like, and converts alternating current input from the external power supply 36 into direct current and outputs the direct current.
The switching transformer 35b includes a primary coil and a secondary coil that are insulated from each other, and includes a primary coil and a primary side to which direct current is input from the rectifier circuit 35a, and a secondary coil that is induced on the primary side. It consists of a secondary side that outputs direct current. Direct current is input to the primary side from the rectifier circuit 35b and connected to an oscillation circuit 35d to be described later, and PWM control is performed, and the rerectified and smoothed direct current is output to the secondary side.

The feedback circuit 35c performs detection comparison of the output voltage or output current from the secondary side, and performs control to turn on and off the primary side to the oscillation circuit 35d so that the output from the secondary side is constant. Yes.
The oscillation circuit 35d performs PWM control on the primary side so that the current flowing through the primary coil of the switching transformer 35b is pulsed.

  In the present embodiment, the output terminal of the power supply circuit 35 is connected to the inverter circuit 45 via the backlight switch 60. The backlight switch 60 switches connection / disconnection between the inverter circuit 45 and the power supply circuit 35 under the control of the microcomputer 40.

(2) Operation of power supply circuit in pseudo P-ON setting:
In the liquid crystal television 10 in the present embodiment, when power supply to the power supply circuit 35 is started from the external power supply 36, power is first supplied to the microcomputer 40. Then, the microcomputer 40 does not display an image on the screen, but performs standby setting for waiting for the remote control light receiving unit 55 to receive an operation input instructing execution of the on setting from the remote control 56 (standby).

  In the standby setting, power is not consumed or hardly consumed in each part other than the microcomputer 40. That is, the load of the power supply circuit 35 in the standby setting is almost only the microcomputer 40. At this time, the power supply circuit 35 intermittently performs the primary oscillation.

  The microcomputer 40 constantly monitors the remote control light receiving unit 55. When the remote control light receiving unit 55 receives a signal indicating an operation input instructing power-on from the remote control 56 in the standby setting, the microcomputer 40 receives the operation input and displays the video on the screen. Execute the on setting to be displayed. When the remote control light receiving unit 55 receives a signal indicating an operation input for instructing power off from the remote control 56 in the ON setting, the operation input is accepted and standby setting is performed so that no video is displayed on the screen.

  As described above, the microcomputer 40 that receives the operation input from the remote controller 56 during the standby setting execution and executes the on-setting, and the microcomputer 40 that receives the operation input from the remote controller 56 and executes the standby setting during the voice execution are displayed. The switching execution means is configured to switch and execute the on setting for displaying the image on the screen and the standby setting with less power consumption than the on setting without displaying an image on the screen.

  Furthermore, in the present invention, immediately after the power supply from the external power supply 36 is started, the standby setting is executed after the pseudo P-ON setting is executed. As described above, in the standby setting, only the microcomputer 40 consumes power, but in the pseudo P-ON setting, the parts other than the microcomputer 40 for a predetermined time (except for the backlight 30b and the inverter circuit 45) are the same as the on setting. Let's do the operation. That is, each part other than the microcomputer 40 (excluding the backlight 30b and the inverter circuit 45) consumes power, so that the load on the power supply circuit 35 increases and the drive voltage of the switching transformer 35b is stabilized.

  Hereinafter, the operation of the power supply circuit 35 immediately after the AC is turned on and the processing of the microcomputer 40 will be described with reference to FIG. In the figure, the state of the power supply circuit 35 immediately after the AC is turned on and the processing of the microcomputer 40 are shown in a flowchart.

  When the user inserts the power plug into a commercial power outlet or pushes the main switch to start power supply to the power supply circuit 35 from the external power supply 36, the direct current rectified and smoothed by the rectifier circuit 35a is generated. The power is supplied to the primary side of the switching transformer 35b, and power can be supplied to each part of the liquid crystal television 10 from the secondary side (step S10).

  Next, the power supply circuit 35 starts power supply to the microcomputer 40 (step S12). Then, the microcomputer 40 is activated and a program for executing the pseudo P-ON setting is executed. This program is executed every time power supply to the microcomputer 40 is started. When the program is executed, the microcomputer 40 instructs the image data generation circuit 20, the sound processing unit 50, the panel drive circuit 25, the control circuit 30c, and the liquid crystal panel 30a to perform the same operation as the on setting, and the backlight switch 60. Is output so that the inverter circuit 45 does not supply power to the backlight 30b (step S20).

  In step S20, when the microcomputer 40 instructs each part (except for the backlight 30b and the inverter circuit 45) to perform the same operation as when the power is turned on, the power supply circuit 35 starts supplying power to each part (step S14). At this time, the liquid crystal panel 30a and the control circuit 30c operate according to the video data output from the panel drive circuit 25, so that the liquid crystal of the liquid crystal panel 30a is opened according to the video data. However, since no power is supplied to the backlight 30b, nothing is displayed on the screen.

  On the other hand, after execution of step S20, the microcomputer 40 measures the elapsed time from the execution of step S20 and determines whether or not a predetermined time has elapsed (step S22). If the predetermined time has elapsed, the condition is satisfied and the process proceeds to step S24. If the predetermined time has not elapsed, step S22 is repeated. The predetermined time may be a time until the drive voltage of the switching transformer 35b is stabilized, and an arbitrary time can be set. In this embodiment, it is 2 to 3 seconds. When the predetermined time has elapsed, the drive voltage of the switching transformer 35b is stabilized (step S16).

  The power consumption increases for 2 to 3 seconds until the predetermined time elapses. That is, the power consumption of the pseudo P-ON setting is larger than the power consumption of the standby setting and is smaller than the power consumption of the on setting.

  In step S24, the microcomputer 40 instructs the image data generation circuit 20, the sound processing unit 50, the panel drive circuit 25, the control circuit 30c, and the liquid crystal panel 30a to perform standby setting, and executes pseudo P-ON setting. Exit. At the same time, the load on the power supply circuit 35 is almost only the microcomputer, and the power supply circuit 35 is also set to standby. Therefore, the power supply circuit 35 oscillates stably because the drive voltage is stable while the load is only the microcomputer 40.

(3) Summary:
That is, a liquid crystal display device and a liquid crystal display that can be switched between an on setting for displaying video on the screen and a standby setting that consumes less power than the on setting without displaying video on the screen In a television, immediately after the start of power supply from an external power supply, the entire apparatus excluding the backlight for a predetermined time is set to the on setting and then operated in the standby setting.

As described above, in the liquid crystal display device according to claim 2 corresponding to the present embodiment, the liquid crystal panel that displays an image on the screen, the backlight that illuminates the liquid crystal panel from behind, and the image that is displayed on the screen. Switching execution means for switching and executing the ON setting to be performed and the standby setting that consumes less power than the ON setting without displaying an image on the screen, and power supply from an external power source is started. Then, in the liquid crystal display device activated by the standby setting, immediately after the power supply from the external power supply is started, the liquid crystal display device except the backlight is set to the on setting for a predetermined time, and then the standby setting is set. The configuration is as follows.
That is, when the supply of power to the liquid crystal display device is started, the entire device excluding the backlight for a predetermined time is in the same state as the on setting, and is set to a standby setting after a predetermined time has elapsed.
In the invention according to claim 2 configured as described above, it is possible to provide a liquid crystal display device capable of immediately stabilizing the power supply when the standby setting is executed even immediately after starting the supply of the external power supply. it can.

The invention according to claim 3 is the liquid crystal display device according to claim 2, further comprising a power supply circuit that converts the input voltage on the primary side to a desired voltage via a transformer and outputs the voltage on the secondary side, The power supply circuit is configured to control the primary-side oscillation in accordance with the secondary-side load, and intermittently perform the primary-side oscillation in the standby setting.
That is, the power supply circuit converts the input voltage on the primary side to a desired voltage via a transformer and outputs the voltage to the secondary side, and controls the oscillation on the primary side according to the load on the secondary side to obtain the desired voltage. Is output to the secondary side. In the standby setting, the primary side oscillation is intermittently performed to reduce power consumption.
In the invention according to claim 3 configured as described above, it is possible to further stabilize the power consumption when executing the standby setting and reduce the power consumption.

Furthermore, in the invention according to claim 4, in the liquid crystal display device according to claim 2 or claim 3, the power supply circuit converts the input alternating current into direct current and outputs the output, and the rectification A switching transformer composed of a primary side to which direct current is input from a circuit and a secondary side that outputs direct current induced on the primary side, and PWM for the primary side based on a signal fed back from the secondary side And an oscillation circuit to be controlled.
That is, the rectifier circuit converts the input alternating current into a direct current and outputs it to the switching transformer, and the switching transformer receives a direct current from the rectifier circuit to the primary side and a direct current to the secondary side. The primary side is PWM-controlled based on the output signal and the oscillation circuit fed back from the secondary side.
In the invention according to claim 4 configured as described above, it is possible to further stabilize the power consumption when the standby setting is executed and reduce the power consumption.

Furthermore, the invention according to claim 5 is the liquid crystal display device according to any one of claims 2 to 4, wherein an inverter circuit that supplies power to the backlight, a speaker that outputs sound, and an antenna are provided. A tuner circuit that extracts and outputs a television broadcast signal of a selected channel from a received television broadcast signal, and an image that displays an image on the liquid crystal panel based on the television broadcast signal output by the tuner circuit A processing unit and an audio processing unit that outputs audio to the speaker based on a television broadcast signal output from the tuner circuit, and immediately after power supply from an external power source is started, the liquid crystal panel and the After the inverter circuit, the tuner circuit, the video processing unit, and the audio processing unit are turned on for a predetermined time, There is a configuration in which a standby setting.
That is, the tuner circuit extracts and outputs a television broadcast signal of a selected channel from the television broadcast signal received by the antenna, and the video processing unit is based on the television broadcast signal output by the tuner circuit. Display the image on the liquid crystal panel. The sound processing unit causes the speaker to output sound based on the sound signal extracted and output from the tuner circuit. When power is supplied to the liquid crystal display device, power is supplied to the liquid crystal panel, the inverter circuit, the tuner circuit, the video processing unit, and the audio processing unit for a predetermined time, and the video is A load for the power supply circuit is obtained by performing a process for displaying on the liquid crystal panel. At that time, no power is supplied to the backlight and the backlight is not operated, so that no video is displayed on the screen.
In the invention according to claim 5 configured as described above, it is possible to further stabilize the power consumption when the standby setting is executed and reduce the power consumption.

  Based on the above configuration, the invention of claim 1 is selected from a liquid crystal panel that displays an image on a screen, a backlight that illuminates the liquid crystal panel from behind, and a television broadcast signal received by an antenna. A tuner circuit that extracts and outputs a television broadcast signal of a channel, a video processing unit that displays video on the liquid crystal panel based on the television broadcast signal output by the tuner circuit, and a power source for the backlight In a liquid crystal television comprising: an inverter circuit to be supplied; a speaker that outputs sound; and a sound processing unit that outputs sound to the speaker; a rectifier circuit that converts input alternating current into direct current and outputs; and the rectifier A switch composed of a primary side to which direct current is input from a circuit and a secondary side that outputs direct current induced on the primary side. A power supply circuit including a ring transformer, an oscillation circuit that performs PWM control of the primary side based on a signal fed back according to the load on the secondary side, an on setting for displaying an image on the screen, and an image A microcomputer that switches and executes the standby setting with less power consumption than the on setting without being displayed on the screen, and an operation input means that instructs the microcomputer to switch between the on setting and the standby setting; When power supply from the external power supply to the power supply circuit is started, direct current rectified and smoothed by the rectifier circuit is supplied to the primary side of the switching transformer, and power supply from the secondary side becomes possible. The power supply circuit starts supplying power to the microcomputer, and the microcomputer turns on the liquid crystal panel, the tuner circuit, the video processing unit, and the audio processing unit. The power supply circuit starts supplying power to the liquid crystal panel, the tuner circuit, the video processing unit, and the audio processing unit, and the microcomputer is configured to supply the power supply circuit to the liquid crystal panel, the tuner circuit, and the tuner circuit. The standby setting is executed when a predetermined time has elapsed from the start of power supply to the video processing unit and the audio processing unit, and the power supply circuit stabilizes the drive voltage of the switching transformer in the standby setting, and the primary side The oscillation is intermittently performed.

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.

It is a schematic block diagram of the liquid crystal television according to the present example. It is a schematic block diagram concerning power supply. It is a flowchart which shows the state of the power supply circuit immediately after AC input, and the process of a microcomputer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Liquid crystal television 15a ... Antenna 20 ... Image data generation circuit 30 ... Liquid crystal module 30a ... Liquid crystal panel 30c ... Control circuit 35b ... Switching transformer 35b ... Rectification circuit 35d ... Oscillation circuit 40 ... Microcomputer 45 ... Inverter circuit 50 ... Audio | voice processing part 55. Remote control light receiving part

Claims (5)

A liquid crystal panel that displays video on the screen;
A backlight that illuminates the liquid crystal panel from behind;
A tuner circuit that extracts and outputs a television broadcast signal of a selected channel from a television broadcast signal received by an antenna;
Based on the television broadcast signal output from the tuner circuit, a video processing unit that displays video on the liquid crystal panel;
An inverter circuit for supplying power to the backlight;
A speaker that outputs sound;
An audio processing unit for outputting audio to the speaker;
In LCD televisions with
A switching transformer comprising: a rectifier circuit that converts an input alternating current into a direct current and outputs; a primary side to which direct current is input from the rectifier circuit; and a secondary side that outputs a direct current induced on the primary side; An oscillation circuit that PWM-controls the primary side based on a signal fed back according to the load on the secondary side, and a power supply circuit comprising:
A microcomputer that switches between an on setting that displays video on the screen and a standby setting that consumes less power than the on setting without displaying video on the screen;
Operation input means for instructing the microcomputer to switch between the on setting and the standby setting;
With
When power supply to the power supply circuit is started from an external power supply, direct current rectified and smoothed by the rectifier circuit is supplied to the primary side of the switching transformer, and power can be supplied from the secondary side. Starts supplying power to the microcomputer,
When the microcomputer operates the liquid crystal panel, the tuner circuit, the video processing unit, and the audio processing unit with the on setting, the power supply circuit is connected to the liquid crystal panel, the tuner circuit, the video processing unit, and the audio processing unit. Power supply to the
The microcomputer causes the power supply circuit to execute the standby setting when a predetermined time has elapsed from the start of power supply to the liquid crystal panel, the tuner circuit, the video processing unit, and the audio processing unit,
The liquid crystal television, wherein the power supply circuit stabilizes a drive voltage of the switching transformer in the standby setting and intermittently performs the primary side oscillation. A liquid crystal panel that displays video on the screen;
A backlight that illuminates the liquid crystal panel from behind;
A switching execution means for switching and executing an on setting for displaying video on the screen and a standby setting that does not display video on the screen and consumes less power than the on setting;
With
In the liquid crystal display device activated by the standby setting when power supply from an external power source is started,
Immediately after power supply from an external power source is started, the liquid crystal display device except for the backlight is set to the on setting for a predetermined time and then set to the standby setting. It has a power supply circuit that converts the input voltage on the primary side to a desired voltage via a transformer and outputs it on the secondary side,
3. The power supply circuit according to claim 2, wherein the power supply circuit controls the oscillation on the primary side in accordance with the load on the secondary side, and intermittently performs the oscillation on the primary side in the standby setting. Liquid crystal display device. The power supply circuit
A rectifier circuit that converts input alternating current into direct current and outputs it;
A switching transformer configured by a primary side to which direct current is input from the rectifier circuit and a secondary side that outputs direct current induced on the primary side;
An oscillation circuit that PWM-controls the primary side based on a signal fed back from the secondary side;
The liquid crystal display device according to claim 2 or claim 3, further comprising: An inverter circuit for supplying power to the backlight;
A speaker that outputs sound;
A tuner circuit that extracts and outputs a television broadcast signal of a selected channel from a television broadcast signal received by an antenna;
Based on the television broadcast signal output from the tuner circuit, a video processing unit that displays video on the liquid crystal panel;
An audio processing unit that outputs audio to the speaker based on the television broadcast signal output by the tuner circuit;
With
Immediately after the power supply from the external power source is started, the liquid crystal panel, the inverter circuit, the tuner circuit, the video processing unit, and the audio processing unit are set to the on setting for a predetermined time, and then set to the standby setting. The liquid crystal display device according to claim 2, wherein the liquid crystal display device is a liquid crystal display device.

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