TW201942719A - Common voltage decoupling circuit for touch reception and touch display integrated driver and touch display panel using the same the NMOS transistor providing a rapid charge path so as to shorten the transient time of the surge voltage - Google Patents

Abstract

This invention discloses a common voltage decoupling circuit for touch reception. The common voltage decoupling circuit is provided with an NMOS transistor and a PMOS transistor; the NMOS transistor is provided with a first drain electrode, a first gate electrode and a first source electrode; the first drain electrode is coupled to a direct-current supply voltage, the first gate electrode is coupled to a common voltage, and the first source electrode is coupled to a touch receiving end; the PMOS transistor is provided with a second source electrode, a second gate electrode and a second drain electrode, the second drain electrode is coupled to an earth voltage, the second gate electrode is coupled to the common voltage, and the second source electrode is coupled to the touch receiving end; when a step voltage of a pixel driving unit is coupled to the touch receiving end by virtue of a parasitic capacitor to generate a surge voltage at the touch receiving end in a process that the touch receiving end is driven by a common voltage driver, if the surge voltage has an upward pulse large enough to conduct the PMOS transistor, the PMOS transistor can provide a rapid discharge path so as to shorten the transient time of the surge voltage; and if the surge voltage has a downward pulse large enough to conduct the NMOS transistor, the NMOS transistor can provide a rapid charge path so as to shorten the transient time of the surge voltage.

Description

Common voltage decoupling circuit for touch receiving, and integrated driver and touch display panel using touch display thereof

This case relates to a touch display integrated driving circuit, and more particularly to a common voltage decoupling circuit provided at a touch receiving end of a touch display.

In a TDDI (touch with display driver integration) application, the common voltage for the touch receiving end and the display will share nodes. Please refer to FIG. 1, which illustrates a schematic diagram of a conventional touch display panel. As shown in FIG. 1, since the touch receiving points 21 on a panel 20 and a touch display integrated driving integrated circuit 10 have path impedances 22 (consisting of wiring and switching channels) of different sizes, The driving force of the common voltage VCOM output from the touch display integrated driving integrated circuit 10 to the touch receiving points 21 on the panel 20 will be inconsistent.

In addition, the voltage level of each touch receiving point 21 on the panel 20 during the screen display period is determined by a common voltage source. Please refer to FIG. 2, which illustrates a common voltage driving equivalent circuit when the touch display integrated driving integrated circuit 10 of FIG. 1 operates in a display mode. As shown in FIG. 2, a common voltage driver 11 directly drives each touch receiving point 21. Since the touch display integrated driving integrated circuit 10 has metal wiring and a switch connection inside, there is a path impedance 12 composed of the wiring and the switch channel. When the pixel data (SD1, SD2, SD3) are to be changed, the output of a pixel driving unit (not shown) corresponding to each pixel data will generate a step voltage V _step , and the step voltage V _Step is coupled to a touch receiving point 21 via a parasitic capacitor 23 and a path impedance 22, and a surge voltage V _imp1 is generated between the parasitic capacitor 23 and the path impedance 22 and a surge is generated at the touch receiving point 21 The voltage V _imp . In addition, due to the relationship of the path impedance 12, the driving force of the common voltage driver 11 cannot uniformly and effectively drive all the touch receiving points 21. Under the interference of the surge voltage V _imp , some touch receiving points 21 cannot be pulled to the common voltage VCOM_REF level within a limited charging time, and this uneven voltage distribution will cause the display screen of the panel 20 to be horizontal. Lines or vertical lines.

In order to solve the above problems, a novel touch display integrated driving circuit is urgently needed in the art.

One of the purposes of this case is to provide a common voltage decoupling circuit for touch receiving, which can prevent a display screen from generating horizontal stripes or straight stripes by a simple and reliable circuit design.

Another object of this case is to provide a common voltage decoupling circuit for touch reception, which can effectively suppress a capacitive interference pulse of a pixel driving voltage source through an automatically generated discharge path or charging path to ensure that A display quality.

In order to achieve the above purpose, a common voltage decoupling circuit for touch receiving is proposed, which has:

An NMOS transistor having a first drain, a first gate, and a first source. The first drain is coupled to a DC supply voltage, and the first gate is coupled to a common voltage. And the first source is coupled to a touch receiving terminal; and

A PMOS transistor having a second source, a second gate, and a second drain. The second drain is coupled to a ground voltage, and the second gate is coupled to the common voltage. And the second source is coupled to the touch receiving end;

Wherein, when the touch receiving terminal is driven by a common voltage driver, a step voltage of a pixel driving unit is coupled to the touch receiving terminal through a parasitic capacitor to generate a surge voltage at the touch receiving terminal. When the surge voltage has an upward pulse sufficient to turn on one of the PMOS transistors, the PMOS transistor will provide a fast discharge path to shorten the transient time of the surge voltage; and if the surge voltage has sufficient When one of the NMOS transistors is turned on and the down pulse is turned on, the NMOS transistor will provide a fast charging path to shorten the transient time of the surge voltage.

In addition, the present invention also provides a touch display integrated driver having the common voltage decoupling circuit for touch reception as described above.

In addition, the present invention also provides a touch display panel having the touch display integrated driver as described above.

In order to make the reviewer of the Guigui better understand the structure, characteristics and purpose of this creation, the drawings and detailed description of the preferred embodiments are attached as follows.

Please refer to FIG. 3 and FIG. 4 together, wherein FIG. 3 shows a circuit diagram of an embodiment of a common voltage decoupling circuit for touch receiving according to the present invention; FIG. 4 shows a plurality of common voltage decoupling circuits of FIG. 3 A circuit diagram in a touch display integrated driver 200.

As shown in FIG. 3, the common voltage decoupling circuit includes an NMOS transistor 100 and a PMOS transistor 110 to suppress a surge voltage.

The NMOS transistor 100 has a first drain, a first gate, and a first source. The first drain is coupled to a DC voltage IOVCC. The first gate is coupled to a common voltage VCOM_REF. The first source is coupled to a touch receiving terminal 21.

The PMOS transistor 110 has a second source, a second gate, and a second drain. The second drain is coupled to a ground voltage VCL, and the second gate is coupled to the common voltage VCOM_REF. The second source is coupled to the touch receiving terminal 21.

During a screen display, when the touch receiving terminal 21 is driven by a common voltage driver 11, a step voltage V _{step of} a pixel driving unit (not shown in FIG. 3) is coupled to a parasitic capacitor 23. When the touch receiving terminal 21 generates a surge voltage V _imp at the touch receiving terminal 21, if the surge voltage V _imp has an upward pulse sufficient to turn on the PMOS transistor 110 (that is, the upward pulse Height is greater than the critical voltage of the PMOS transistor 110), the PMOS transistor 110 will provide a fast discharge path to shorten the transient time of the surge voltage; and if the surge voltage V _imp is sufficient to conduct the NMOS transistor One of the down pulses of the crystal 100 (that is, the depth of the down pulse is greater than the critical voltage of the NMOS transistor 100), then the NMOS transistor 100 will provide a fast charging path to shorten the transient of the surge voltage V _imp State time. According to this, the touch receiving terminal 21 can return to the common voltage VCOM_REF level in a short time.

Please refer to FIG. 5, which shows a comparison chart of a surge voltage waveform using the technical solution of the present invention and the technical solution of the present invention. As shown in FIG. 5, the surge voltage V _imp using the technical solution of the present invention can indeed return to the level of the common voltage VCOM_REF in a short time and has a lower coupling amount. In other words, this case can effectively suppress the surge voltage infected by the pixel voltage source, thereby ensuring good picture display quality.

According to the above description, the technical solution of the present invention can be applied to a touch display integrated driver, and can be further applied to a touch display panel.

With the design disclosed above, the present invention has the following advantages:

1. The common voltage decoupling circuit for touch receiving of the present invention can prevent horizontal or straight lines on a display screen by a simple and reliable circuit design.

2. The common voltage decoupling circuit for touch receiving of the present invention can effectively suppress a capacitive interference pulse of a pixel driving voltage source through an automatically generated discharge path or charging path to ensure the quality of a display screen. .

The one disclosed in this case is one of the preferred embodiments, and any change or modification that originates from the technical ideas of this case and is easily inferred by those who are familiar with the technology, does not depart from the scope of patent rights in this case.

10, 200‧‧‧ Touch display integrated drive integrated circuit

11‧‧‧Common voltage driver

12, 22‧‧‧path impedance

20‧‧‧ Panel

21‧‧‧touch receiving point

23‧‧‧parasitic capacitance

100‧‧‧NMOS Transistor

110‧‧‧PMOS transistor

FIG. 1 is a schematic diagram of a conventional touch display panel. FIG. 2 illustrates a common voltage driving equivalent circuit when the touch display integrated driving integrated circuit of FIG. 1 operates in a display mode. FIG. 3 is a circuit diagram of an embodiment of a common voltage decoupling circuit for touch receiving according to the present invention. FIG. 4 is a circuit diagram of a plurality of common voltage decoupling circuits of FIG. 3 arranged in a touch display integrated driver. FIG. 5 shows a comparison chart of the surge voltage waveforms when the technical scheme of the present invention is adopted and the technical scheme of the present invention is not adopted.

Claims (3)

A common voltage decoupling circuit for touch reception includes: an NMOS transistor having a first drain electrode, a first gate electrode, and a first source electrode, the first drain electrode is connected with a direct current Supply voltage coupling, the first gate is coupled to a common voltage, and the first source is coupled to a touch receiving end; and a PMOS transistor having a second source, a first Two gates and a second drain, the second drain is coupled to a ground voltage, the second gate is coupled to the common voltage, and the second source is coupled to the touch receiving end Wherein, when the touch receiving end is driven by a common voltage driver, a step voltage of a pixel driving unit is coupled to the touch receiving end via a parasitic capacitor to generate a sudden burst at the touch receiving end. When the surge voltage has an upward pulse sufficient to turn on one of the PMOS transistors, the PMOS transistor will provide a fast discharge path to shorten the transient time of the surge voltage; and if the surge voltage Has a sufficient pulse to turn on one of the NMOS transistors , The NMOS transistor provides a fast charging path to shorten the time of the transient surge voltage. A touch display integrated driver has a common voltage decoupling circuit for touch reception as described in item 1 of the scope of patent application. A touch display panel includes a touch display integrated driver as described in item 2 of the patent application scope.