Data line driver capable of generating fixed gradation voltage without switches
In a data line driver for driving data lines of a display apparatus including a data register adapted to sequentially latch video data signals in synchronization with latch signals, a data latch circuit adapted to latch all the sequential video data signals latched in the data register in synchronization with a strobe signal to generate digital output signals, a digital/analog converter adapted to convert the digital output signals of the data latch circuit into analog signals, and an output buffer adapted to apply the analog signals of the digital/analog converter to the data lines, the data latch circuit has a reset terminal adapted to receive a reset signal, so that the digital output signals of the data latch circuit are reset by the reset signal to fixed gradation data regardless of the strobe signal.
1. A data line driver for driving data lines of a display apparatus, comprising:
a data register adapted to sequentially latch video data signals in synchronization with latch signals;
a data latch circuit adapted to latch all said sequential video data signals latched in said data register in synchronization with a strobe signal to generate digital output signals;
a digital/analog converter adapted to convert the digital output signals of said data latch circuit into analog signals; and
an output buffer adapted to apply the analog signals of said digital/analog converter to said data lines,
said data latch circuit having a reset terminal adapted to receive a reset signal, so that the digital output signals of said data latch circuit are reset by said reset signal to fixed gradation data regardless of said strobe signal.
2. The apparatus as set forth in claim 1 , wherein said fixed gradation data represents black data.
3. The apparatus as set forth in claim 1 , wherein said fixed gradation data represents white data.
4. The apparatus as set forth in claim 1 , wherein said fixed gradation data represents an intermediate data between black data and white data.
5. The apparatus as set forth in claim 1 , wherein said data latch circuit comprises a plurality of latch circuits for one of said data lines,
said latch circuits fetching said video data signals in synchronization with said strobe signal when said reset signal is at a first level,
said latch circuits being reset when said reset signal is at a second level.
6. The apparatus as set forth in claim 5 , wherein each of said latch circuits is reset to generate a low level signal.
7. The apparatus as set forth in claim 5 , wherein each of said latch circuits is reset to generate a high level signal.
8. The apparatus as set forth in claim 5 , wherein at least one of said latch circuits is reset to generate a low level signal, and at least one of said latch circuits is reset to generate a high level signal.
9. The apparatus as set forth in claim 5 , wherein each of said latch circuits comprises a reset-type D-type latch circuit with a data terminal adapted to receive one bit of one of said sequential video data signals, a gate terminal adapted to receive said strobe signal, a reset terminal adapted to receive said reset signal, and an output terminal adapted to generate a corresponding bit of one of the digital output signals of said data latch circuit.
10. The apparatus as set forth in claim 9 , wherein data at the output terminal of each of said latch circuits is the same as data at the data terminal thereof when data at the gate terminal and the reset terminal thereof are at a first level, and wherein data at the output terminal of each of said latch circuits is “0” or “1” when data at the reset terminal thereof is at a second level.