TOUCH SENSOR PANEL CONTROLLER AND SEMICODUCTOR DEVICE

• US 20120287081A1
• Filed: 05/09/2012
• Published: 11/15/2012
• Est. Priority Date: 05/09/2011
• Status: Active Grant

• Current Assignee: Synaptics Japan GK (Synaptics Incorporated)
• Original Assignee: Renesas SP Drivers Inc. (Synaptics Incorporated)
• Inventors: AKAI, Akihito, ISHII, Tatsuya, ENDO, Kazuya, NOTOMI, Shinobu, KODAMA, Akihiro
• Granted Patent: US 9,195,352 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• 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: G09G 3/2092 Details of a display terminals using a flat panel, the details relating to the control arrangement of the display terminal and to the interfaces thereto suitable for both CRT and flat panel G09G5/003; specific for a CRT G09G1/165

Abstract

Provided is a touch sensor panel which can increase the detection sensitivity of a touch relatively readily. The touch sensor panel controller supplies drive electrodes of a touch sensor panel with a high-voltage AC drive signal with its low level set to a negative voltage and drives them. The time of change of a drive waveform supplied to the drive electrodes of the touch sensor panel is shifted relative to the time of change of a drive waveform supplied to a display scan electrode. The touch sensor panel controller uses a charge pump in synchronization with clock signals of more than one phase to produce a high drive voltage to activate drive electrodes of the touch sensor panel, and the clock signals of more than one phase are initialized each time the drive electrode is subjected to AC pulse driving.

Claims

1. A touch sensor panel controller for a touch sensor panel having Y electrodes, X electrodes, and a capacitance formed at each of intersections of the X and Y electrodes, the controller comprising:

a drive circuit which drives the Y electrodes of the touch sensor panel;

a detection circuit which accepts input of signals from the X electrodes, and detects a capacitance value of the capacitance at each intersection; and

a control part which controls the drive circuit and the detection circuit,

wherein the drive circuit applies a pulse of AC drive voltage with its low level made a negative voltage to the Y electrodes.

2. The touch sensor panel controller according to claim 1, wherein the control circuit decides the negative voltage level based on select data supplied from outside.

3. A semiconductor device comprising:

a touch sensor panel controller for a touch sensor panel having Y electrodes, X electrodes, and a capacitance formed at each of intersections of the X and Y electrodes, which drives the Y electrodes of the touch sensor panel, accepts input of signals from the X electrodes, and detects capacitance values of the capacitances at the intersections, and which has a drive circuit operable to apply a pulse of AC drive voltage with its low level made a negative voltage to the Y electrodes; and

a display driver which supplies a display drive voltage to an active matrix type display panel having display cells at points where scan and signal electrodes intersect each other.

4. The semiconductor device according to claim 3, wherein the display driver has a step-up circuit operable to produce voltages used for driving the scan and signal electrodes, and

the drive circuit uses a voltage produced by the step-up circuit for both or one of high and low level voltages of the AC drive voltage.

5. The semiconductor device according to claim 3, wherein the touch sensor panel controller further includes a control part operable to decide the negative voltage level based on select data provided from outside.

6. The semiconductor device according to claim 3, comprising a structure composed of one of a single chip having the touch sensor panel controller and the display driver formed on a common semiconductor substrate, and a multichip having the touch sensor panel controller and the display driver formed on separate semiconductor substrates.

7. A semiconductor device comprising:

a touch sensor panel controller for a touch sensor panel having Y electrodes, X electrodes, and a capacitance formed at each of intersections of the X and Y electrodes, which drives the Y electrodes of the touch sensor panel, accepts input of signals from the X electrodes, and detects a capacitance value of the capacitance at each intersection; and

a display driver which supplies a display drive voltage to an active matrix type display panel having display cells at points where scan and signal electrodes intersect each other,

wherein the touch sensor panel controller has a first drive circuit operable to apply a first pulse waveform to the Y electrodes,

the display driver has a second drive circuit operable to apply a second pulse waveform to the scan electrodes of the LC display panel, and

the first and second drive circuits are arranged so that a high level period of the first pulse waveform is within a high level period of the second pulse waveform, and the first pulse waveform is smaller than the second pulse waveform in the width of the high level thereof.

8. The semiconductor device according to claim 7, wherein the second drive circuit produces the second pulse waveform based on a drive timing of the display panel, and

the first drive circuit produces the first pulse waveform based on the drive timing of the display panel, provided that the high level period of the first pulse waveform is set within the high level period of the second pulse waveform, and the first pulse waveform is set to be smaller than the second pulse waveform in the width of the high level thereof.

9. The semiconductor device according to claim 8, wherein the timing of change of the first pulse waveform is set by setting, on the first drive circuit, a wait time (t1) which is an elapse of time after the rising of the second pulse waveform, and a set time (t3) before the falling of the second pulse waveform.

10. A touch sensor panel controller for a touch sensor panel having Y electrodes, X electrodes, and a capacitance formed by the X and Y electrodes at each of intersections thereof, the controller comprising:

a drive circuit operable to drive the Y electrodes of the touch sensor panel;

a detection circuit operable to accept input of a signal from the X electrode and to detect a capacitance value of the capacitance at the intersection; and

a step-up circuit operable to produce a power source voltage for operating the drive circuit and the detection circuit,

wherein the drive circuit applies more than one pulse waveform to each Y electrode to activate the Y electrode,

the step-up circuit performs a charge pump operation in synchronization with pulse changes of charge clock signals of more than one phase, and

the charge clock signals of more than one phase are initialized in units of cycles of driving by more than one pulse waveform for each Y electrode.

11. The touch sensor panel controller according to claim 10, wherein the step-up circuit has a counter which counts clock signals and produces the charge clock signals of more than one phase based on outputs of required digits, and

the counter has a count value initialized in units of cycles of driving by more than one pulse waveform for each Y electrode.

12. A semiconductor device comprising:

a touch sensor panel controller for a touch sensor panel having Y electrodes, X electrodes, and a capacitance formed by the X and Y electrodes at each of intersections thereof, the controller having a drive circuit operable to drive the Y electrodes of the touch sensor panel, and a detection circuit operable to accept input of a signal from the X electrode and to detect a capacitance value of the capacitance at the intersection;

a display driver operable to supply a display drive voltage to an active matrix type display panel having scan electrodes, signal electrodes, and display cells located at points where the scan electrodes and signal electrodes intersect each other; and

a step-up circuit,

wherein the drive circuit applies more than one pulse waveform to each Y electrode to drive the Y electrode,

the step-up circuit produces power source voltages to operate the drive circuit, the detection circuit and the display driver, and performs a charge pump operation in synchronization with pulse changes of charge clock signals of more than one phase, and

the charge clock signals of more than one phase are initialized in units of cycles of driving by more than one pulse waveform for each Y electrode.

13. The semiconductor device according to claim 12, wherein the step-up circuit has a counter which counts clock signals and produces the charge clock signals of more than one phase based on outputs of required digits, and

the counter has a count value initialized in units of cycles of driving by more than one pulse waveform for each Y electrode.