Control method, circuit, and electronic system utilizing the same

• US 8,446,361 B2
• Filed: 02/19/2009
• Issued: 05/21/2013
• Est. Priority Date: 03/14/2008
• Status: Active Grant

• Current Assignee: InnoLux Corporation
• Original Assignee: InnoLux Corporation
• Inventors: Hsueh, Fu-Yuan, Wu, I-Lin
• Primary Examiner(s): Shalwala, Bipin
• Assistant Examiner(s): Ketema, Benyam
• Application Number:
  US12/378,930
• Publication Number:
  US 20090231302A1
• Time in Patent Office: 1,552 Days
• Field of Search: 345/174, 200/600
• US Class Current: 345/156
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/044 by capacitive means

Abstract

A control circuit for a touch panel including a capacitor module coupled to a node. The control circuit includes a power supply, a discharging unit, and a compared unit. The power supply provides a voltage to the node. The discharging unit discharges the node. The compared unit generates an output signal according to the voltage of the node.

Claims

1. A control method for a touch panel, which comprises a capacitor module coupled to a node, comprising:

providing a voltage to the node during a first period;

discharging the node during a second period; and

generating an output signal according to the voltage of the node;

wherein the node is discharged by a first current during the second period,

wherein the node is discharged by a second current when the duration, that the node is discharged by the first current, arrives at a preset timing,

wherein a first transition occurs in the output signal when the voltage of the node arrives at a first preset value and a second transition occurs in the output signal when the voltage of the node is less than a second preset value; and

wherein the touch panel is touched or not according to the timing difference between the first and the second transitions.

2. The control method as claimed in claim 1, wherein the voltage is not provided to the node when the voltage of the node arrives at the first preset value.

3. The control method as claimed in claim 1, wherein the second current is less than the first current.

4. The control method as claimed in claim 3, wherein the node is not discharged when the voltage of the node is less than the second preset value.

5. A control circuit for a touch panel comprising a capacitor module coupled to a node, comprising:

a power supply providing a voltage to the node;

a discharging unit discharging the node; and

a compared unit generating an output signal according to the voltage of the node

wherein the discharging unit comprises a first module to discharge the node by a first current and a second module to discharge the node by a second current which is less than the first current,

wherein a first transition occurs in the output signal when the voltage of the node arrives at a first preset value and a second transition occurs in the output signal when the voltage of the node is less than a second preset value.

6. The control circuit as claimed in claim 5, further comprising a determination unit, wherein the determination unit obtains whether the touch panel is touched or not according to a timing difference between the first and the second transitions.

7. The control circuit as claimed in claim 6, wherein the node is discharged by the second current when the duration, that the node is discharged by the first current, arrives at a preset timing.

8. The control circuit as claimed in claim 7, wherein the second module stops discharging the node when the node is discharged by the second current and the voltage of the node is less than the second preset value.

9. An electronic system, comprising:

a power converter generating an operation power; and

a touch panel receiving the operation power and comprising;

a capacitor module coupled to a node; and

a control circuit controlling the voltage of the node and comprising;

a power supply providing a voltage to the node;

a discharging unit discharging the node; and

a compared unit generating an output signal according to the voltage of the node wherein the discharging unit comprises a first module to discharge the node by a first current and a second module to discharge the node by a second current which is less than the first current,

wherein a first transition occurs in the output signal when the voltage of the node arrives at a first preset value and a second transition occurs in the output signal when the voltage of the node is less than a second preset value, and wherein the electronic system further comprises a determination unit obtaining whether the touch panel is touched or not according to a timing difference between the first and the second transitions.

10. The electronic system as claimed in claim 9, wherein the second module stops discharging the node when the node is discharged by the second current and the voltage of the node is less than the second preset value.

11. The electronic system as claimed in claim 10, wherein the node is discharged by the second current when the duration, that the node is discharged by the first current, arrives at a preset timing.

12. An electronic system as claimed in claim 9, wherein the touch panel further comprises a color filter and the color filter and the capacitor module are disposed on a substrate.