Device and Method for Driving a Touch Pad

• US 20090066665A1
• Filed: 06/18/2008
• Published: 03/12/2009
• Est. Priority Date: 09/11/2007
• Status: Abandoned Application

• Current Assignee: Integrated Device Technology Incorporated (Renesas Electronics Corporation)
• Original Assignee: Leadin Technology Co., Ltd.
• Inventors: LEE, In Wook
• Application Number:
  US12/141,646
• Publication Number:
  US 20090066665A1
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/041661 using detection at multiple resolutions, e.g. coarse and fine scanning; using detection within a limited area, e.g. object tracking window
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

Provided are a device for driving a touch pad, including: an input unit that receives an electrical signal be touching from channels of the touch pad; and a control logic unit that scans the channels. The control logic unit includes a channel selection section which divides the touch pad into a plurality of regions and selects the channels which are to be scanned, wherein the ration of the number of total channels to the number of channels to be scanned is different according to each of the plurality of divided regions. In accordance with the present invention, the scanning speed of the touch pad is improved and, thereby, the response speed of other elements which are operated depending on whether the touch pad is touched or not is enhanced.

Claims

1. A device for driving a touch pad, comprising:

an input unit that receives an electrical signal by touching from channels of the touch pad; and

a control logic unit that scans the channels,

wherein the control logic unit comprises a channel selection section which divides the touch pad into a plurality of regions and selects the channels which are to be scanned, and the ratio of the number of total channels to the number of channels to be scanned is different according to each of the plurality of divided regions.

2. The device according to claim 1,

wherein the touch pad includes a fine region and a coarse region, and

the channel selection section selects m channels from n channels in the fine region and selects k channels from j channels in the coarse region, where n, m, j, and k are natural numbers, and the relationships n≧

m, j≧

k, and m/n>

k/j are satisfied.

3. The device according to claim 1,

wherein the touch pad includes a fine region and a coarse region, and

the channel selection section divides the coarse region into a plurality of regions, selects m channels from n channels in the fine region, selects k channels from j channels in some regions of the coarse region, and selects i channels from h channels in the other regions of the coarse region, where n, m, j, k, h, and i are natural numbers, and the relationships n >

m,j>

k, h>

i and m/n>

k/j>

i/hare satisfied.

4. The device according to claim 1,

wherein the touch pad includes a fine region and a coarse region, and

the channel selection section divides the coarse region into a plurality of regions, selects m channels from n channels in the fine region, selects k channels from j channels in some regions of the coarse region, and selects i channels from h channels in the other regions of the coarse region, where n, m, j, k, and h are natural numbers, i is 0, and the relationships n≧

m, j>

k, and m/n>

k/j are satisfied.

5. The device according to claim 2,

wherein when the channel selection section divides the touch pad into a plurality of regions, a neighboring region including a position touched at a previous scan is designated as the fine region, and the other region excluding the fine region is designated as the coarse region.

6. The device according to claim 3,

wherein when the channel selection section divides the touch pad into a plurality of regions, a neighboring region including a position touched at a previous scan is designated as the fine region, and the other region excluding the fine region is designated as the coarse region.

7. The device according to claim 4,

wherein when the channel selection section divides the touch pad into a plurality of regions, a neighboring region including a position touched at a previous scan is designated as the fine region, and the other region excluding the fine region is designated as the coarse region.

8. The device according to claim 1, further comprising:

a capacitance-to-digital converter (CDC) unit that outputs high or low values according to the electrical signal; and

a memory unit that stores the values outputted from the CDC unit and positional information of the touch pad.

9. A method for driving a touch pad, comprising the steps of:

receiving an electrical signal by touching from channels of the touch pad;

at a channel selection unit of a control logic unit, dividing the touch pad into a plurality of regions; and

scanning channels by varying the ratio of the number of total channels to the number of channels to be scanned according to each of the plurality of divided regions.

10. The method according to claim 9,

wherein the touch pad includes a fine region and a coarse region, and

in the scanning of the channels, the control logic unit selects m channels from n channels in the fine region and selects k channels from j channels in the coarse region and scans the selected channels, where n, m, j, and k are natural numbers, and the relationships n≦

m, j>

k, and m/n>

k/j are satisfied.

11. The method according to claim 9,

wherein the touch pad includes a fine region and a coarse region, and

in the scanning of the channels, the control logic unit divides the coarse region into a plurality of regions, selects m channels from n channels in the fine region, selects k channels from j channels in some regions of the coarse region, and selects i channels from h channels in the other regions of the coarse region and scans the selected channels, where n, m, j, k, h, and i are natural numbers, and the relationships n≧

m, j>

k, h>

i and m/n>

k/j>

i/h are satisfied.

12. The method according to claim 9,

wherein the touch pad includes a fine region and a coarse region, and

in the scanning of the channels, the control logic unit divides the coarse region into a plurality of regions, selects m channels from n channels in the fine region, selects k channels from j channels in some regions of the coarse region, and selects i channels from h channels in the other regions of the coarse region and scans the selected channels, where n, m, j, k, and h are natural numbers, i is 0, and the relationships n≧

m, j>

k, and m/n>

k/j are satisfied.

13. The method according to claim 10,

wherein in said dividing the touch pad into a plurality of regions, when the channel selection section divides the touch pad into a plurality of regions, a neighboring region including a position touched at a previous scan is designated as the fine region, and the other region excluding the fine region is designated as the coarse region.

14. The method according to claim 11,

wherein in said dividing the touch pad into a plurality of regions, when the channel selection section divides the touch pad into a plurality of regions, a neighboring region including a position touched at a previous scan is designated as the fine region, and the other region excluding the fine region is designated as the coarse region.

15. The method according to claim 12,

wherein in said dividing the touch pad into a plurality of regions, when the channel selection section divides the touch pad into a plurality of regions, a neighboring region including a position touched at a previous scan is designated as the fine region, and the other region excluding the fine region is designated as the coarse region.

16. The method according to claim 9, further comprising the steps of:

outputting high or low values according to the electrical signal from a capacitance-to-digital converter (CDC) unit; and

storing the values outputted form the CDC unit and positional information of the touch pad into a memory unit.