Computer graphics processing and selective visual display system – Display driving control circuitry
Utility Patent
1998-06-26
2001-01-02
Hjerpe, Richard A. (Department: 2774)
Computer graphics processing and selective visual display system
Display driving control circuitry
C345S205000, C345S211000, C345S213000
Utility Patent
active
06169539
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to an analog video signal selection circuit for liquid crystal displays (LCDs), and more particularly to an analog video signal selection circuit for selecting one of video signals from two different channels.
A selection circuit for selecting one of video signals received from different channels for LCDs has been not disclosed. The video signal selection circuit has been demanded in LCDs applied to car navigation systems.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an analog video signal selection circuit for automatically or manually selecting one of video signals from two different channels.
According an aspect of the present invention, there is provided to an analog video signal selection circuit for a liquid crystal display which selects one of first data of R
1
, G
1
and B
1
received from a first channel or second data of R
2
, G
2
and B
2
received from a second channel, comprising: a mode selection means for generating a first channel selection signal and a second channel selection signal in a manual mode and generating an automode selection signal in a auto mode; a data selection means for selecting one of the first data of R
1
, G
1
and B
1
received from the first channel or the second data R
2
, G
2
and B
2
received from the second channel and providing the selected data as R, G and B output signals in accordance with the first and second channel selection signals and the automode selection signal generated from the mode selection means; and a synchronous signal selection means for selecting one of a first synchronous data of horizontal and vertical synchronous signals from the first channe and a second synchronous data of horizontal and vertical synchronous signals from the second channel in accordance with the first and second channel selection signals and the automode selection signal generated from the mode selection means.
The mode selection means comprises a switch where a common terminal is connected to ground and movable terminals for generating the selection signals are connected the data selection means and the synchronous signal selection means.
The analog video signal selection circuit further comprising a priority channel selection means which detects a signal received from the priority channel of two channel and generates a first signal for selecting a priority channel to the data selection means and the synchronous signal selection means when the signal is received from the priority channel, or a second signal for selecting another channel of two channels to the data selection means and the synchronous signal selection means when the signal is not received from the priority channel, according to the automode selection signal. The priority channel selection means preferentially selects the first channel of two channels and generates the priority channel selection signal for selecting the first channel, when the horizontal synchronous signal is received from the first channel.
The priority channel selection means includes: a first signal generation means generates the first detection signal for selecting the priority channel of two channels, when the horizontal synchronous signal is received from the first channel in automode selection; a second signal generation means generates the second detection signal for selecting another channel of two channels, when the horizontal synchronous signal is not received from the first channel in automode selection; a detecting means for detecting the horizontal synchronous signal received from the first channel to drive one of the first signal generation means and the second signal generation means; and an enable means for enabling the first and second signal generation means in accordance with the automode selection signal received from the mode selection means.
The data selection means includes: a R data selection means for selecting one of the R
1
data from the first channel or the R
2
data from the second channel; a G data selection means for selecting one of the G
1
data from the first channel or the G
2
data from the second channel; a B data selection means for selecting one of the B
1
data from the first channel or the B
2
data from the second channel; and an output disable means for blocking the output of one of the first data of the first channel or the second data of the second channel in accordance with the first and second channel selection signals received from the mode selection means.
Each of the R, G, B data selection means includes: a first input means for receiving the first data from the first channel; a first output means for providing the first data received from the first input means as the R, G, or B output signal; a second input means for receiving the second data from the second channel; and a second output means for providing the second data from the second input means. The output disable means includes: a first disable means for simultaneously disabling all the first output means of the R, G and D data selection means in accordance with the first channel selection signal received from the mode selection means; and a second disable means for simultaneously disabling all second output means of the R, G and D data selection means in accordance with the second channel selection signal received from the mode selection means.
The synchronous signal selection means includes: a first selection means for selecting the synchronous signals of the first channel according to the first channel selection signal received from the mode selection means; and a second selection means for selecting the synchronous signals of the second channel according to the second channel selection signal received from the mode selection means.
The first selection includes: an output means for outputting the horizontal synchronous signal and the vertical synchronous signal from the first channel as the output synchronous signals; and a control means for controlling the output means by the first channel selection signal received from the mode selection means.
The second selection includes: a first input means for receiving the horizontal synchronous signal from the second channel; a second input means for receiving the vertical synchronous signal from the second channel; an output means for outputting the horizontal synchronous signal and the vertical synchronous signal of the second channel received from the first and second input means as the output synchronous signals; and a controlling means for controlling the output means by the second channel selection signal received from the mode selection means.
There is also provided to an analog video signal selection circuit for a liquid crystal display which selects one of first data of R
1
, G
1
and B
1
received from a first channel or second data of R
2
, G
2
and B
2
received from a second channel, comprising: a mode selection means for generating a first channel selection signal and a second channel selection signal in a manual mode and generating an automode selection signal in a auto mode; a data selection means for selecting one of the first data of R
1
, G
1
and B
1
received from the first channel or the second data R
2
, G
2
and B
2
received from the second channel and providing the selected data as R, G and B output signals in accordance with the first and second channel selection signals and the automode selection signal generated from the mode selection means; a synchronous signal selection means for selecting one of a first synchronous data of horizontal and vertical synchronous signals from the first channel and a second synchronous data of horizontal and vertical synchronous signals from the second channel in accordance with the first and second channel selection signals and the automode selection signal generated from the mode selection means; and a priority channel selection means which detects a signal received from the priority channel of two channel and generates a first signal for selecting a priority channel to the data selection means and the synchronous s
Kim Myung Ho
Lee Jin Sun
Hjerpe Richard A.
Hyundai Electronics Industries Co,. Ltd.
Nguyen Kimnhung
Selitto & Associates, P.C.
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