ACTIVE TOUCH PANEL VOLTAGE COMPENSATION CIRCUIT

• US 20090231286A1
• Filed: 03/12/2008
• Published: 09/17/2009
• Est. Priority Date: 03/12/2008
• Status: Abandoned Application

• Current Assignee: DanoTech Co., Ltd.
• Original Assignee: DanoTech Co., Ltd.
• Inventors: Kuo, Chun-Ting
• Application Number:
  US12/046,906
• Publication Number:
  US 20090231286A1
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• 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
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

An active touch panel voltage compensation circuit, which is to improve voltage distribution in the border of an electrode layer of a touch panel, comprises: a power supply unit provides an initial voltage to a plurality of voltage-applying points of the electrode layer. A differential amplifier unit sets a calibration level. The differential amplifier unit is coupled to a plurality of detection points to obtain a plurality of detected voltages, and compares the detected voltages with the calibration level to obtain a plurality of deviation values. A processing unit works out the compensation voltages for the voltage-applying points according to the deviation values, generates a plurality of gain-modulation signals according to the compensation voltages and sends the gain-modulation signals to the power supply unit. The power supply unit regulates the initial voltage to the plurality of compensation voltages so that the detected voltages can reach the calibration level.

Claims

1. An active touch panel voltage compensation circuit, which is to improve voltage distribution in the border of an electrode layer of a touch panel, comprising:

a power supply unit providing an initial voltage to a plurality of voltage-applying points to start said touch panel;

a differential amplifier unit setting a calibration level, coupled to a plurality of detection points respectively arranged besides corresponding said voltage-applying points to obtain a plurality of detected voltages, and comparing said detected voltages with said calibration level to obtain a plurality of deviation values; and

a processing unit working out compensation voltages for said voltage-applying points according to said deviation values, sending a plurality of gain-modulation signals to said power supply unit according to said compensation voltages to make said power supply unit regulate said initial voltage to the plurality of said compensation voltages and make voltages detected in said detection points reach said calibration level, so that voltage attenuation-induced deflections between two said voltage-applying points are corrected.

2. The active touch panel voltage compensation circuit according to claim 1, wherein said deviation value is proportional to said compensation voltage.

3. The active touch panel voltage compensation circuit according to claim 1, wherein said deviation value is inversely proportional to said compensation voltage.

4. The active touch panel voltage compensation circuit according to claim 1, wherein said power supply unit further comprises a plurality of voltage gain circuits, which respectively control voltages output to the plurality of said voltage-applying points.

5. The active touch panel voltage compensation circuit according to claim 1, wherein an AC/DC converter is arranged in between said differential amplifier unit and said processing unit.

6. The active touch panel voltage compensation circuit according to claim 1, wherein said differential amplifier unit further comprise a differential amplifier and a multiplex switch;

said multiplex switch sequentially conducts said detected voltages to said differential amplifier, and said differential amplifier sequentially generate the plurality of said deviation values.

7. The active touch panel voltage compensation circuit according to claim 1, wherein said differential amplifier unit comprises a plurality of differential amplifiers corresponding to the plurality of said detection points, and the plurality of said differential amplifiers simultaneously generates the plurality of said deviation values.

8. The active touch panel voltage compensation circuit according to claim 7, wherein said processing unit receiving the plurality of said deviation values is a multiplex processor.