TOUCH POWER CIRCUIT HAVING OPERATIONAL AMPLIFIER AND TOUCH DISPLAY DEVICE USING THE SAME

• US 20180188865A1
• Filed: 11/14/2017
• Published: 07/05/2018
• Est. Priority Date: 12/30/2016
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Granted Patent: US 10,444,881 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 2203/04107 Shielding in digitiser, i.e. guard or shielding arrangements, mostly for capacitive touchscreens, e.g. driven shields, driven grounds
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2330/02 Details of power systems and of start or stop of display operation
• CPC Class Codes: G09G 3/3677 suitable for active matrices only
• CPC Class Codes: G09G 3/3688 suitable for active matrices only
• CPC Class Codes: H03F 2203/45116 Feedback coupled to the input of the differential amplifier
• CPC Class Codes: H03F 2203/45151 At least one resistor being added at the input of a dif amp
• CPC Class Codes: H03F 3/45179 using MOSFET transistors as the active amplifying circuit H03F3/45278 takes precedence

Abstract

Disclosed are a touch power circuit and a touch display device in which an operational amplifier buffers an input pulse having a first voltage and a higher second voltage alternate, and uses the buffered input pulse to provide an output pulse. The operational amplifier includes a non-inverting input terminal to which the input pulse is supplied, an inverting input terminal connected to the output terminal, and an output unit driven according to a result of amplifying a difference between a voltage of the non-inverting input terminal and a voltage of the inverting input terminal and configured to charge and discharge the output terminal. The circuits and devices may further include an offset voltage applier configured to supply an offset voltage having a first polarity to the non-inverting input terminal and/or the inverting input terminal to level-shift the input pulse.

Claims

1. A touch power circuit, comprising:

an operational amplifier configured to buffer an input pulse in which a first voltage and a second voltage greater than the first voltage alternate, and to output the buffered input pulse to an output terminal as an output pulse, the operational amplifier including;

a non-inverting input terminal to which the input pulse is supplied,

an inverting input terminal connected to the output terminal, and

an output unit that is driven based at least in part by a result of amplifying a difference between a voltage of the non-inverting input terminal and a voltage of the inverting input terminal, and that is configured to charge and discharge the output terminal using a high-potential power voltage higher than the second voltage and a low-potential power voltage similar to the first voltage, or to charge and discharge the output terminal using a high-potential power voltage similar to the second voltage and a low-potential power voltage lower than the first voltage, and

an offset voltage applier configured to additionally supply an offset voltage having a first polarity to any one of the non-inverting input terminal and the inverting input terminal,

wherein the output pulse is level-shifted relative to the input pulse by the offset voltage.

2. The touch power circuit according to claim 1, wherein the output pulse is level-shifted to be higher than the input pulse upon charging and discharging the output terminal using the high-potential power voltage higher than the second voltage and the low-potential power voltage similar to the first voltage.

3. The touch power circuit according to claim 1, wherein the output pulse is level-shifted to be lower than the input pulse upon charging and discharging the output terminal using the high-potential power voltage similar to the second voltage and the low-potential power voltage lower than the first voltage.

4. The touch power circuit according to claim 1, wherein the operational amplifier buffers a first offset voltage and receives from the offset voltage applier a second offset voltage having a positive polarity, wherein an absolute value of the second offset voltage is higher than the first offset voltage to cause a total offset voltage of the operational amplifier to constantly maintain the positive polarity of the second offset voltage.

5. The touch power circuit according to claim 1, wherein the first voltage is a gate-off low voltage, the second voltage is a gate-off high voltage, the input pulse is a first gate-off modulation signal, and the output pulse is a second gate-off modulation signal,

wherein the output unit of the operational amplifier is configured to charge and discharge the output terminal using a high-potential power voltage higher than the gate-off high voltage and a low-potential power voltage similar to the gate-off low voltage, or to charge and discharge the output terminal using a high-potential power voltage similar to the gate-off high voltage and a low-potential power voltage lower than the gate-off low voltage, and

wherein the second gate-off modulation signal is level-shifted relative to the first gate-off modulation signal by the offset voltage.

6. The touch power circuit according to claim 5, wherein the second gate-off modulation signal is level-shifted to be higher than the first gate-off modulation signal upon charging and discharging the output terminal using the high-potential power voltage higher than the gate-off high voltage and the low-potential power voltage similar to the gate-off low voltage.

7. The touch power circuit according to claim 5, wherein the second gate-off modulation signal is level-shifted to be lower than the first gate-off modulation signal upon charging and discharging the output terminal using the high-potential power voltage similar to the gate-off high voltage and the low-potential power voltage lower than the gate-off low voltage.

8. The touch power circuit according to claim 5, further comprising:

a second operational amplifier configured to buffer a first touch driving signal in which a common high voltage and a common low voltage alternate, and to output the buffered first touch driving signal as a second touch driving signal, wherein the second touch driving signal and the second gate-off modulation signal have a same phase and a same amplitude.

9. The touch power circuit according to claim 1,

wherein the first voltage is a common low voltage, the second voltage is a common high voltage, the input pulse is a first touch driving signal, and the output pulse is a second touch driving signal,

wherein the output unit of the operational amplifier is configured to charge and discharge the output terminal using the high-potential power voltage higher than the common high voltage and the low-potential power voltage similar to the common low voltage, or to charge and discharge the output terminal using the high-potential power voltage similar to the common high voltage and the low-potential power voltage lower than the common low voltage, and

wherein the second touch driving signal is level-shifted relative to the first touch driving signal by the offset voltage.

10. The touch power circuit according to claim 9, wherein the second touch driving signal is level-shifted to be higher than the first touch driving signal upon charging and discharging the output terminal using the high-potential power voltage higher than the common high voltage and the low-potential power voltage similar to the common low voltage.

11. The touch power circuit according to claim 9, wherein the second touch driving signal is level-shifted to be lower than the first touch driving signal upon charging and discharging the output terminal using the high-potential power voltage similar to the gate-off high voltage and the low-potential power voltage lower than the common low voltage.

12. The touch power circuit according to claim 9, wherein the operational amplifier is configured to buffer a first gate-off modulation signal in which a gate-off low voltage and a gate-off high voltage alternate, and to output the buffered first gate-off modulation signal as a second gate-off modulation signal,

wherein the second gate-off modulation signal and the second touch driving signal have a same phase and a same amplitude.

13. A touch display device, comprising:

a touch power circuit;

a touch-compatible data driver configured to supply a first touch driving signal supplied from the touch power circuit to touch electrodes and data lines of a panel during a touch driving period; and

a gate driver configured to supply a first gate-off modulation signal supplied from the touch power circuit to gate lines of the panel during the touch driving period,

the touch power circuit comprising;

an operational amplifier configured to buffer an input pulse in which a first voltage and a second voltage greater than the first voltage alternate, and to output the buffered input pulse to an output terminal as an output pulse, the operational amplifier including;

a non-inverting input terminal to which the input pulse is supplied,

an inverting input terminal connected to the output terminal, and

an output unit that is driven at least in part by a result of amplifying a difference between a voltage of the non-inverting input terminal and a voltage of the inverting input terminal, and that is configured to charge and discharge the output terminal using a high-potential power voltage higher than the second voltage and a low-potential power voltage similar to the first voltage, or to charge and discharge the output terminal using a high-potential power voltage similar to the second voltage and a low-potential power voltage lower than the first voltage, and

an offset voltage applier configured to supply an offset voltage having a first polarity to any one of the non-inverting input terminal and the inverting input terminal,

wherein;

the output pulse is level-shifted relative to the input pulse by the offset voltage,

the first voltage is a gate-off low voltage, the second voltage is a gate-off high voltage, the input pulse is a second gate-off modulation signal, and the output pulse is the first gate-off modulation signal, and

the first gate-off modulation signal is level-shifted relative to the second gate-off modulation signal by the offset voltage.

14. The touch display device according to claim 13, wherein the first gate-off modulation signal is level-shifted to be higher than the second gate-off modulation signal upon charging and discharging the output terminal using the high-potential power voltage that is higher than the gate-off high voltage and the low-potential power voltage that is similar to the gate-off low voltage.

15. The touch display device according to claim 13, wherein the first gate-off modulation signal is level-shifted to be lower than the second gate-off modulation signal upon charging and discharging the output terminal using the high-potential power voltage that is similar to the gate-off high voltage and the low-potential power voltage that is lower than the gate-off low voltage.

16. The touch display device according to claim 13, further comprising:

a second operational amplifier configured to buffer a second touch driving signal in which a common high voltage and a common low voltage alternate, and to output the buffered second touch driving signal as the first touch driving signal,

wherein the first touch driving signal and the first gate-off modulation signal have a same phase and a same amplitude.

17. A touch display device, comprising:

a touch power circuit;

a touch-compatible data driver configured to supply a first touch driving signal supplied from the touch power circuit to touch electrodes and data lines of a panel during a touch driving period; and

a gate driver configured to supply a first gate-off modulation signal supplied from the touch power circuit to gate lines of the panel during the touch driving period,

the touch power circuit comprising;

an operational amplifier configured to buffer an input pulse in which a first voltage and a second voltage greater than the first voltage alternate, and to output the buffered input pulse to an output terminal as an output pulse, the operational amplifier including;

a non-inverting input terminal to which the input pulse is supplied,

an inverting input terminal connected to the output terminal, and

an output unit that is driven based at least in part by a result of amplifying a difference between a voltage of the non-inverting input terminal and a voltage of the inverting input terminal, and that is configured to charge and discharge the output terminal using a high-potential power voltage higher than the second voltage and a low-potential power voltage similar to the first voltage, or to charge and discharge the output terminal using a high-potential power voltage similar to the second voltage and a low-potential power voltage lower than the first voltage, and

an offset voltage applier configured to additionally supply an offset voltage having a first polarity to any one of the non-inverting input terminal and the inverting input terminal,

wherein;

the first voltage is a common low voltage, the second voltage is a common high voltage, the input pulse is a second touch driving signal, and the output pulse is the first touch driving signal, and

the first touch driving signal is level-shifted relative to the second touch driving signal by the offset voltage.

18. The touch power circuit according to claim 17, wherein the first touch driving signal is level-shifted to be higher than the second touch driving signal upon charging and discharging the output terminal using the high-potential power voltage that is higher than the common high voltage and the low-potential power voltage that is similar to the common low voltage.

19. The touch power circuit according to claim 17, wherein the first touch driving signal is level-shifted to be lower than the second touch driving signal upon charging and discharging the output terminal using the high-potential power voltage similar to the gate-off high voltage and the low-potential power voltage lower than the common low voltage.

20. The touch power circuit according to claim 17, further comprising:

a second operational amplifier configured to buffer the first gate-off modulation signal in which a gate-off low voltage and a gate-off high voltage alternate, and to output the buffered first gate-off modulation signal as a second gate-off modulation signal,

wherein the second gate-off modulation signal and the second touch driving signal have a same phase and a same amplitude.