KR100758915B1 - Apparatus and method for safety switching output image of dtv system - Google Patents

Abstract

An apparatus and a method for switching an image output of a DTV(Digital TV) system are provided to switch the output of the DTV system to a PC monitor and output the output of the DTV system normally by exactly maintaining a physical connection state of a cable between the PC monitor and the DTV system and turning on/off only a logical connection state. A PC monitor(100) displays a digital image transmitted from a TV set(200). DVI/HDMI(Digital Video/visual Interactive/High Definition Multimedia Interface) connectors(110,210) are formed in the PC monitor(100) and the TV set(200), and are connected by a cable. The DVI/HDMI connectors(110,210) transmit and receive digital image and audio signals. An HDMI receiver(220) receives a cable connection signal transmitted from the PC monitor(100). A driving unit(240) outputs an HPD(Hot Plug Detect) signal from the TV set(200) to the PC monitor(100). An EEPROM(Electrically Erasable and Programmable ROM)(230) stores EDID(Extended Display IDentification) data of the TV set(200), and outputs the stored EDID data to the PC monitor(100) through the DVI/HDMI connectors(110,210). A switching element(260) physically turns on/off a connection state between the EEPROM(230) and the DVI/HDMI connector(210). A CPU(250) judges that the HPD signal is changed from a high level to a low level in a state that the cable is connected between the DVI/HDMI connectors(110,210), turns off the switching element(260), and blocks the output of the EDID data from the EEPROM(230).

Description

Apparatus and method for safety switching output image of DTV system}

1 is a block diagram showing a video output switching device of a conventional DTV system.

2 is a control flowchart illustrating a video output switching method of a conventional DTV system.

Figure 3 is a block diagram showing an image output switching device of the DTV system according to the present invention.

4 is a control flowchart illustrating a video output switching method of a DTV system according to the present invention;

<Description of the symbols for the main parts of the drawings>

100: PC monitor 110, 210: DVI / HDMI connector

120: cable 200: TV set

220: HDMI receiver 230: memory

240 drive unit 250 control unit

260: switching element

The present invention relates to a DTV system, and more particularly, to an apparatus and method for converting video output of a DTV system for converting an output of the DTV system to a PC monitor.

In general, a video display device is a device for displaying image information by using a screen, and typical devices include a television system for receiving a radio wave of a broadcasting station and displaying a video, and a hard disk built in a set-top box or a television body. And a personal video recorder (PVR) for recording and playing back information.

In conventional analog television broadcasting, video signals to be transmitted are modulated by AM or FM and transmitted through radio waves or cables. With the recent development of digital technologies such as digital image compression and digital modulation and demodulation, the standardization of digital television (DTV) broadcasting is rapidly progressing, and existing terrestrial, satellite and cable broadcasting are based on MPEG (Moving Picture Experts Group). Is digitizing.

As such, digital broadcasting can provide higher quality of service than analog service according to the development of digital video / audio compression technology and digital transmission technology, and can transmit multiple broadcast programs in the same bandwidth, digital communication media and digital storage. There is an advantage in that interoperability with the media can be improved.

1 is a block diagram illustrating a video output switching device of a conventional DTV system, and FIG. 2 is a control flowchart illustrating a video output switching method of a conventional DTV system.

As shown, the image output switching device of the conventional DTV system includes a PC monitor 10, a DVI / HDMI connector 11, 21, a TV set 20, an HDMI receiver 22, a memory 23, an eastern part. (24).

The PC monitor 10 displays the digital image transmitted from the TV set 20 on the screen.

The DVI / HDMI connectors 11 and 21 are connected to each other with a cable 12 to transmit and receive digital video and audio signals to and from the PC monitor 10 and the TV set 20, respectively.

DVI (digital video / visual interactive) refers to a technology for compressing and restoring digital images. It was developed around Intel as a moving picture technology that can store video images as digital data and play them back on a computer. DVI is a technology that defines the standard of image information stored on a CD-ROM. Video) You can save data to a single disc.

In addition, HDMI (High Definition Multimedia Interface) is a technology that can transmit digital video and audio signals all at once with one cable.

The HDMI receiver 22 receives a cable connection signal, and the driver 24 outputs a Hot Plug Detect (HPD) signal to the PC monitor 10 to signal that the cable set state is recognized by the TV set 20. Output The memory 23 stores a set of EDID data.

Here, the extended display indentification data (EDID) is a standard for transferring display information from the display side to the host side. The meaning of EDID does not define an interface signal like the display data channel (DDC), but rather displays the capability of the display to the host. It is to define the data type to pass.

The video output switching device of the conventional DTV system configured as described above, as shown in FIG. 3, first, when the DVI-HDMI cable 12 is connected (S101), the VGA of the PC monitor 10 is connected through the cable 12. A cable connection signal (5V signal) is supplied from the card (not shown) to the TV set 200 (S102).

The HDMI receiver 22 receives the cable connection signal, and the driver 24 outputs a Hot Plug Detect (HPD) signal to the PC monitor 10 to recognize the cable connection state in the TV set 20. To output (S103).

After a while (approximately 9ms have elapsed), the PC monitor 10 reads the EDID data of the set from the memory 23 and outputs a video signal corresponding thereto (S104 to S105).

As such, the image output switching device of the conventional DTV system can switch the screen output to the RF / AV / Component of the PC monitor 10 and the TV set 20.

However, if the input is changed from the input of the PC monitor 10 to the RF / AV / Component of the TV set 20, the set 20 causes the HPD signal to go from high to low and the PC The monitor 10 does not send an output. At this time, when switching the output from the TV set 20 to the PC monitor 10 again, the PC monitor 10 returns to the PC input even if the HPD signal is made high. Since the cable connection is maintained, the video signal is not output due to an abnormality on the signal line.

That is, it is determined whether the cable is connected through DDC communication, and whether the video signal is output is determined by recognizing not only the DDC but also the HPD signal. At this time, in case of normal signal output, the TV set receives the HPD signal, performs DDC communication, reads an EDID file, and outputs an image signal. However, the PC monitor does not output the video signal even if the input is changed to make the HPD signal low and then returns to the HDMI / DVI input to make the HPD signal high. For PC monitors, DDC communication is always performed when the HPD signal changes from low to high and high to low. Therefore, when it is changed from low to high, EDID should be read for normal output. If it is changed from high to low, it is recognized that the EDID should not be read. However, if the HPD signal is changed from high to low as above, but the connector is still connected, the PC monitor will recognize the abnormal state when EDID is read.

Therefore, in the conventional video output switching device of the DTV system, when a PC monitor is connected to a TV set, the input is switched to watch an image, and when the image is switched (restored) to the PC input again, the image is not displayed on the PC monitor screen. there was.

Therefore, the present invention is to solve the above-mentioned conventional problems, by maintaining the physical connection state of the cable between the PC monitor and the DTV system as it is by switching the output of the DTV system to the PC monitor only by turning on / off the logical connection state It is an object of the present invention to provide an apparatus and method for converting video output of a DTV system to be normally output.

In order to achieve the above object, a video output switching device of a DTV system according to the present invention includes a PC monitor displaying a digital video transmitted from a TV set on a screen; DVI / HDMI connectors respectively formed on the PC monitor and the TV set and connected to each other by cables to transmit and receive digital video and audio signals; An HDMI receiver for receiving a cable connection signal transmitted from the PC monitor; A driver for outputting a Hot Plug Detect (HPD) signal from the TV set to the PC monitor; A memory storing EDID (extended display indentification data) data of the TV set and outputting to the PC monitor via the DVI / HDMI connector; A switching element for physically turning on / off a connection state between the memory and a DVI / HDMI connector; And determining that the HPD signal is changed from high to low in a state where a cable is connected between the DVI / HDMI connectors, and turning off the switching element to block the EDID data from being output from the memory. do.
In addition, the video output switching method of the DTV system of the present invention comprises the steps of determining the state that the cable is connected between the PC monitor and the DVI / HDMI connector formed on each TV set; Receiving a cable connection signal transmitted from the PC monitor and outputting a Hot Plug Detect (HPD) signal from the TV set to the PC monitor; Outputting EDID (extended display indentification data) data of the TV set stored in a memory to the PC monitor via the DVI / HDMI connector; When it is determined that the HPD signal is changed from high to low in a state where a cable is connected between the DVI / HDMI connectors, turning off a switching element to block EDID data from being output from the memory. It is done.
Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

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3 is a block diagram showing an image output switching device of the DTV system according to the present invention.

As shown, the present invention is a PC monitor 100, DVI / HDMI connectors 110, 210, cable 120, TV set 200, HDMI receiver 220, memory 230, driver 240 ), The controller 250 and the switching element 260.

The PC monitor 100 displays the digital image transmitted from the TV set 200 on the screen.

DVI / HDMI connectors 110 and 210 are respectively formed on the PC monitor 100 and the TV set 200, and are connected to each other by a cable 120 to transmit and receive digital video and audio signals.

The HDMI receiver 220 receives a cable connection signal transmitted from the PC monitor 100.

The memory 230 stores EDID (extended display indentification data) data of the TV set 200 and outputs it to the PC monitor 100 through the DVI / HDMI connectors 110 and 210. The memory 230 is preferably a nonvolatile memory such as a ROM, an EPROM, or an EEPROM. The EDID data stored in the memory 230 includes output information of a video signal.

The driver 240 outputs a Hot Plug Detect (HPD) signal from the TV set 200 to the PC monitor 100.

The controller 250 determines that the HPD signal is changed while the cable 120 is connected between the DVI / HDMI connectors 110 and 210, and turns off the switching element 260 to output the EDID data. Block it. In this case, the controller 250 determines that the HPD signal is changed by recognizing that the HPD signal is changed from high to low or from low to high.

The HPD signal includes a signal for recognizing a state in which the cable 120 is connected between the PC monitor 100 and the DVI / HDMI connectors 110 and 210 of the TV set 200.

The controller 250 may be a conventional micro-computer (MICOM) or other central processing unit (CPU or MPU) and the like.

The switching element 260 physically turns on / off the connection state between the memory 230 and the DVI / HDMI connector 210 in the TV set 200.

4 is a control flowchart illustrating a video output switching method of a DTV system according to the present invention.

As shown, the present invention, step S201 of determining the state in which the cable 120 is connected between the PC monitor 100 and the DVI / HDMI connector 110, 210 formed in the TV set 200; Receiving cable connection signals transmitted from the PC monitor 100 and outputting a Hot Plug Detect (HPD) signal from the TV set 200 to the PC monitor 100 (S202 to S203); Outputting EDID data including output information of the video signal of the TV set 200 stored in the memory 230 to the PC monitor 100 through the DVI / HDMI connectors 110 and 210 (S205 ~). S206); When the cable 120 is connected between the DVI / HDMI connectors 110 and 210, the HPD signal for recognizing the cable is changed, that is, the HPD signal is high to low Or (S204 to S207) blocking the output of the EDID data from the memory 230 when it is determined to change from low to high.

Referring to the operation of the present invention configured as described above is as follows.

First, it is determined whether the cable 120 is connected between the DVI / HDMI connectors 110 and 210 formed on the PC monitor 100 and the TV set 200 (S201).

That is, the DVI / HDMI connectors 110 and 210 are respectively formed on the PC monitor 100 and the TV set 200, and are connected to each other by a cable 120 to transmit and receive digital video and audio signals. Here, the cable 120 means a conventional wired connection method, but in addition to the technical concept of the present invention, RF or infrared wireless connection is also possible.

Thereafter, the cable connection signal transmitted from the PC monitor 100 is received, and a Hot Plug Detect (HPD) signal is output from the TV set 200 to the PC monitor 100 (S202 to S203).

At this time, the HDMI receiver 220 receives the cable connection signal transmitted from the PC monitor 100, the driver 240 from the TV set 200 to the PC monitor 100 HPD (Hot Plug Detect) To output a signal.

In this state, the EDID data including the output information of the video signal of the TV set 200 stored in the memory 230 is output to the PC monitor 100 through the DVI / HDMI connector 110, 210. (S205 to S206).

Therefore, the PC monitor 100 displays the digital image transmitted from the TV set 200 on the screen.

Meanwhile, when the cable 120 is connected between the DVI / HDMI connectors 110 and 210, the HPD signal for recognizing the cable is changed, that is, the HPD signal is high to low. When it is determined to change from low or low to high, the output of EDID data from the memory 230 is blocked (S204 to S207).

That is, the controller 250 determines that the HPD signal is changed while the cable 120 is connected between the DVI / HDMI connectors 110 and 210, and turns off the switching element 260 to remove EDID data. Shut off the output.

The controller 250 determines that the HPD signal is changed by recognizing that the HPD signal is changed from high to low or from low to high, and the cable 120 is changed. The cable 120 is determined to be connected between the PC monitor 100 and the DVI / HDMI connector 110 and 210 of the TV set 200 through the HPD signal including the signal for recognizing the connected state.

Accordingly, the switching element 260 physically turns off the connection state between the memory 230 and the DVI / HDMI connector 210 in the TV set 200 under the control of the controller 250. The output of EDID data is blocked.

As described above, the present invention changes the input to make the HPD signal low and then returns to the HDMI / DVI input to make the PCD signal high even when the HPD signal is made high. When switching elements 260 such as transistors or FETs are formed at the line ends, and the HPD signal is changed from high to low, the cable is physically turned off by switching off the switching element 260 during the period when the PC monitor 100 requires EDID data. By truncation, EDID data stored in the EEPROM memory 230 cannot be read. Afterwards, when switching to the HDMI input again, the HPD signal is changed from low to high, and the PC monitor 100 reads EDID data from the EEPROM memory 230 and outputs the screen normally.

The present invention described above can be applied not only to flat panel display devices such as PDPs and LCDs, but also to projection TVs, general TVs, monitors, and other video devices, and can be equally applied to analog TVs, digital TVs, and satellite TVs. . In addition, it can be applied to all NTSC, PAL, SECAM.

Although the preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the above-described embodiments, and the present invention is not limited to the above-described embodiments without departing from the spirit of the present invention as claimed in the claims. Anyone skilled in the art can, of course, make various changes and make such changes as fall within the stated claims.

As described above, according to the apparatus and method for switching the video output of the DTV system according to the present invention, the output of the DTV system is controlled by turning on / off only the logical connection state while maintaining the physical connection state of the cable between the PC monitor and the DTV system. Switch to the monitor reliably. Specifically, the HPD signal is pulled low (or high) for sequential switching output from PC monitor to TV set to PC monitor and then returned to the HDMI / DVI input to make the HPD signal high (or low). It is effective to prevent the video signal from being output to the PC monitor so that a normal screen is output.

Claims (9)

A PC monitor displaying a digital image transmitted from a TV set on a screen; DVI / HDMI connectors respectively formed on the PC monitor and the TV set and connected to each other by cables to transmit and receive digital video and audio signals; An HDMI receiver for receiving a cable connection signal transmitted from the PC monitor; A driver for outputting a Hot Plug Detect (HPD) signal from the TV set to the PC monitor; A memory storing EDID (extended display indentification data) data of the TV set and outputting to the PC monitor via the DVI / HDMI connector; A switching element for physically turning on / off a connection state between the memory and a DVI / HDMI connector; And determining that the HPD signal is changed from high to low in a state where a cable is connected between the DVI / HDMI connectors, and turning off the switching element to block the EDID data from being output from the memory. Video output switching device of the DTV system. The method of claim 1, The control unit, After determining that the HPD signal is changed from high to low, the switching device is turned off to block the EDID data from being output. Then, the HPD signal is determined to be changed from low to high, and the switching device is turned on. And outputting EDID data from the memory. The method of claim 1, The memory is a video output switching device of the DTV system, characterized in that the ROM, EPROM, EEPROM or the like is a nonvolatile memory. The method of claim 1, EDID data stored in the memory, the video output switching device of the DTV system, characterized in that it comprises the output information of the video signal. The method of claim 1, The HPD signal is a video output switching device of the DTV system, characterized in that it comprises a signal for recognizing the state that the cable is connected between the PC monitor and the DVI / HDMI connector of the TV set. Determining a state in which a cable is connected between a DVI / HDMI connector respectively formed on the PC monitor and the TV set; Receiving a cable connection signal transmitted from the PC monitor and outputting a Hot Plug Detect (HPD) signal from the TV set to the PC monitor; Outputting EDID (extended display indentification data) data of the TV set stored in a memory to the PC monitor via the DVI / HDMI connector; When it is determined that the HPD signal is changed from high to low in a state where a cable is connected between the DVI / HDMI connectors, turning off a switching element to block EDID data from being output from the memory. Video output switching method of the DTV system. The method of claim 6, After determining that the HPD signal is changed from high to low, the switching device is turned off to block the EDID data from being output. Then, the HPD signal is determined to be changed from low to high, and the switching device is turned on. And outputting the EDID data from the memory. The method of claim 6, EDID data stored in the memory, the video output switching method of the DTV system, characterized in that it comprises the output information of the video signal. The method of claim 6, The HPD signal is a video output switching method of the DTV system, characterized in that it comprises a signal for recognizing the state that the cable is connected between the PC monitor and the DVI / HDMI connector of the TV set.

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