Semiconductor device

• US 9,619,067 B2
• Filed: 03/04/2015
• Issued: 04/11/2017
• Est. Priority Date: 03/18/2014
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Japan GK (Synaptics Incorporated)
• Inventors: Okamura, Kazuhiro
• Primary Examiner(s): Eurice, Michael J
• Application Number:
  US14/638,859
• Publication Number:
  US 20150268778A1
• Time in Patent Office: 769 Days
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• 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 2320/0219 Reducing feedthrough effects in active matrix panels, i.e. voltage changes on the scan electrode influencing the pixel voltage due to capacitive coupling

Abstract

A display signal drive circuit is configured to output a display signal having a signal level based on a common voltage to a display panel. A touch detection signal drive circuit is configured to output a touch detection signal having a signal level based on the common voltage to a touch panel in case that a composite panel is an in-cell type, and is configured to output a touch detection signal having a signal level based on a voltage level other than the common voltage to the touch panel in case that the composite panel is an on-cell type.

Claims

1. A semiconductor device configured for connection to a composite panel having a display panel and a touch panel laminated therein, comprising:

a display signal drive circuit; and

a touch detection signal drive circuit,

wherein the display signal drive circuit is configured to output a display signal having a signal level based on a common voltage to the display panel, and the touch detection signal drive circuit is configured to output a touch detection signal to the touch panel,

wherein the display signal drive circuit comprises a switch configured to make the touch detection signal have a signal level based on the common voltage in case that the composite panel is an in-cell type, and configured to make the touch detection signal have a signal level based on a voltage level other than the common voltage in case that the composite panel is an on-cell type.

2. The semiconductor device according to claim 1, further comprising a variable power supply circuit configured to generate a variable voltage,

wherein in case that the composite panel is an on-cell type, the touch detection signal drive circuit is configured to output a touch detection signal having a signal level based on the variable voltage generated by the variable power supply circuit, to the touch panel, as the voltage level other than the common voltage.

3. The semiconductor device according to claim 1, further comprising a terminal for specifying whether the composite panel to be connected is an in-cell type or an on-cell type.

4. The semiconductor device according to claim 1, further comprising a power supply circuit configured to generate a plurality of internal power supplies including the first power supply for supplying the common voltage, on the basis of an external power supply,

wherein in case that the composite panel is an on-cell type, the touch detection signal drive circuit is configured to select one power supply from the external power supply and the one or more internal power supplies that are generated from the power supply circuit, as the voltage level other than the common voltage, and outputs a touch detection signal having a signal level based on the selected power supply to the touch panel.

5. The semiconductor device according to claim 4, further comprising a gate control driver configured to drive a gate control circuit of the display panel,

wherein the power supply circuit generates a plurality of internal power supplies including the first power supply for supplying the common voltage, on the basis of an external power supply on the positive electrode side and an external power supply on the negative electrode side,

the power supply circuit includes a booster circuit configured to boost each of the external power supplies on the positive electrode side and the negative electrode side, and a stabilizing circuit configured to stabilize an output of the booster circuit, the power supply circuit configured to generate gate drive power supplies on the positive electrode side and the negative electrode side using the booster circuit and the stabilizing circuit to supply the generated gate drive power supplies to the gate control driver, and

the plurality of internal power supplies include an internal reference power supply on the negative electrode side, an output of the booster circuit, and the gate drive power supply.

6. The semiconductor device according to claim 1, further comprising a system interface for connection to a host processor and a register for specifying whether the composite panel to be connected is an in-cell type or an on-cell type,

wherein the register is writably configured by the host processor through the system interface.

7. The semiconductor device according to claim 6, wherein an initial value of the register at the time of power-on is set to a value for specifying that the composite panel to be connected is an in-cell type.

8. The semiconductor device according to claim 1, further comprising a power supply circuit configured to generate a first power supply for supplying the common voltage and a second power supply having the voltage level other than the common voltage, on the basis of an external power supply on a positive electrode side and an external power supply on a negative electrode side.

9. The semiconductor device according to claim 8, wherein the power supply circuit generates an internal reference power supply on the negative electrode side, and supplies the generated internal reference power supply to the touch detection signal drive circuit, as the second power supply having the voltage level other than the common voltage.

10. The semiconductor device according to claim 8, wherein the external power supply on the negative electrode side is supplied to the touch detection signal drive circuit, as the second power supply having the voltage level other than the common voltage.

11. The semiconductor device according to claim 8, further comprising a gate control driver configured to drive a gate control circuit of the display panel,

wherein the power supply circuit is configured to generate gate drive power supplies on the positive electrode side and the negative electrode side to supply the generated gate drive power supplies to the gate control driver, and supplies the gate drive power supply on the negative electrode side to the touch detection signal drive circuit, as the second power supply having the voltage level other than the common voltage.

12. The semiconductor device according to claim 8, further comprising a gate control driver configured to drive a gate control circuit of the display panel,

wherein the power supply circuit includes a booster circuit configured to boost each of the external power supplies on the positive electrode side and the negative electrode side, and a stabilizing circuit configured to stabilize an output of the booster circuit, the power supply circuit configured to generate gate drive power supplies on the positive electrode side and the negative electrode side using the booster circuit and the stabilizing circuit to supply the generated gate drive power supplies to the gate control driver, and

the power supply circuit is configured to supply an output power supply of the booster circuit on the negative electrode side to the touch detection signal drive circuit, as the second power supply having the voltage level of the common voltage.