Display driving apparatus and display apparatus module

• US 20020080131A1
• Filed: 10/19/2001
• Published: 06/27/2002
• Est. Priority Date: 12/26/2000
• Status: Active Grant

• Current Assignee: Shenzhen Torey Microelectronic Technology Co., Ltd.
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Fujino, Hiroaki
• Granted Patent: US 6,756,959 B2
• Time in Patent Office: Days
• US Class Current: 345/208
• CPC Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• CPC Class Codes: G09G 2310/0297 Special arrangements with multiplexing or demultiplexing of display data in the drivers for data electrodes, in a pre-processing circuitry delivering display data to said drivers or in the matrix panel, e.g. multiplexing plural data signals to one D/A converter or demultiplexing the D/A converter output to multiple columns
• CPC Class Codes: G09G 2320/02 Improving the quality of display appearance
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/2011 by amplitude modulation
• CPC Class Codes: G09G 3/3688 suitable for active matrices only
• CPC Class Codes: G09G 3/3696 Generation of voltages supplied to electrode drivers

Abstract

A display driving apparatus in accordance with the present invention outputs a plurality of types of driving voltages that vary depending on display data to display device from a plurality of output terminals for liquid crystal driving voltages via voltage follower circuits. Each of the voltage follower circuits is connected with the output terminals for liquid crystal driving voltages via an analog switch circuit. The analog switch circuit is shared by the output terminals for liquid crystal driving voltages in accordance with the switching of the analog switch circuit. This allows to suppressing the increasing in the circuit scale with the increasing in the number of terminals and the increasing of the power consumption.

Claims

1. A display driving apparatus, in which a plurality of types of driving voltages that vary depending on display data are outputted to display means from a plurality of output terminals via low impedance output means, wherein:

each of the low impedance output means is connected with the plurality of output terminals via switch means, and

the low impedance output means is shared by the plurality of output terminals in response to the switch means.

3. The display driving apparatus as set forth in claim 1, further comprising:

a plurality of blocks, each block including one of the low impedance output means;

the switch means; and

the plurality of output terminals connected with the low impedance output means via the switch means, and

switch control means for controlling in a time-sharing manner the switch means so that the low impedance output means is successively connected with one of the plurality of output terminals,

the switch control means controlling the switch means so that respective timings at which the switch means of the respective blocks are in a connecting state are shifted to each other among the blocks.

8. The display driving apparatus as set forth in claim 1, wherein the low impedance output means cuts off internal operation current during non-operation.

2. A display driving apparatus comprising:

voltage generation means for generating a variety of types of voltages that drive display means in accordance with display data;

a plurality of output terminals;

voltage selection means for selecting and outputting one driving voltage for every output terminal among the plurality of types driving voltages in accordance with the display data;

low impedance output means having a low output impedance;

switch means for connecting or disconnecting each of the low impedance output means with or from the voltage selection means and the plurality of output terminals; and

switch control means for controlling in a time-sharing manner the switch means so that the low impedance output means is successively connected with one of the plurality of output terminals.

4. The display driving apparatus as set forth in claim 2, further comprising:

a plurality of blocks, each block including each of the low impedance output means;

the switch means; and

the plurality of output terminals connected with the low impedance output means via the switch means,

the switch control means controlling the switch means so that respective timings at which the switch means of the respective blocks are in a connecting state are shifted to each other among the blocks.

5. The display driving apparatus as set forth in claim 2, wherein the switch control means stops the operation of the switch means when it is not necessary for the output terminals to output the driving voltages.

6. The display driving apparatus as set forth in claim 2, wherein the voltage selection means is directly connected with the output terminals via a plurality of output lines, the low impedance output means is provided so as to be connected in parallel with the output lines via the switch means, and an output of the voltage selection means is directly supplied to the output terminal irrespective of whether an output of the low impedance output means exists or not.

7. The display driving apparatus as set forth in claim 2, wherein the voltage selection means is directly connected with the output terminals via a plurality of output lines, the low impedance output means is provided so as to be connected in parallel with the output lines via the switch means, and an output of the voltage selection means is directly supplied to the output terminal even after cutting off an output of the low impedance output means.

9. The display driving apparatus as set forth in claim 2, wherein the low impedance output means cuts off internal operation current during non-operation.

10. A display apparatus module comprising a display driving apparatus,

the display driving apparatus outputting a plurality of types of driving voltages that vary depending on display data to a display means from a plurality of output terminals via low impedance output means,

each of the low impedance output means being connected with the plurality of output terminals via a switch means, and

the low impedance output means being shared by the plurality of output terminals in response to the switch means.

12. The display apparatus module as set forth in claim 10, further comprising:

a plurality of blocks, each block including one of the low impedance output means;

the switch means; and

the plurality of output terminals connected with the low impedance output means via the switch means, and

switch control means for controlling in a time-sharing manner the switch means so that the low impedance output means is successively connected with one of the plurality of output terminals, and

the switch control means controlling the switch means so that respective timings at which the switch means of the respective blocks are in a connecting state are shifted to each other among the blocks.

17. The display apparatus module as set forth in claim 10, wherein the low impedance output means cuts off internal operation current during non-operation.

11. A display apparatus module comprising a display driving apparatus, the display driving apparatus including:

voltage generation means for generating a variety of types of voltages that drive display means in accordance with display data;

a plurality of output terminals;

voltage selection means for selecting and outputting one driving voltage for every output terminal among the plurality of types driving voltages in accordance with the display data;

low impedance output means having a low output impedance;

switch means for connecting or disconnecting each of the low impedance output means with or from the voltage selection means and the plurality of output terminals; and

switch control means for controlling in a time-sharing manner the switch means so that the low impedance output means is successively connected with one of the plurality of output terminals.

13. The display apparatus module as set forth in claim 11, further comprising:

a plurality of blocks, each block including one of the low impedance output means;

the switch means; and

the plurality of output terminals connected with the low impedance output means via the switch means, and

the switch control means controlling the switch means so that respective timings at which the switch means of the respective blocks are in a connecting state are shifted to each other among the blocks.

14. The display apparatus module as set forth in claim 11, wherein the switch control means stops the operation of the switch means when it is not necessary for the output terminals to output the driving voltages.

15. The display apparatus module as set forth in claim 11, wherein the voltage selection means is directly connected with the output terminals via a plurality of output lines, the low impedance output means is provided so as to be connected in parallel with the output lines via the switch means, and an output of the voltage selection means is directly supplied to the output terminal irrespective of whether an output of the low impedance output means exists or not.

16. The display apparatus module as set forth in claim 11, wherein the voltage selection means is directly connected with the output terminals via a plurality of output lines, the low impedance output means is provided so as to be connected in parallel with the output lines via the switch means, and an output of the voltage selection means is directly supplied to the output terminal even after cutting off an output of the low impedance output means.

18. The display apparatus module as set forth in claim 11, wherein the low impedance output means cuts off internal operation current during non-operation.