CN102193694A - Electronics for Compensating Capacitance Deviations - Google Patents

Abstract

The electronic device includes: a touch input device; a touch sensing circuit coupled to the touch input device; and a capacitance deviation compensation circuit. The capacitance deviation compensation circuit includes: the first offset compensation capacitor array is coupled to a reference voltage or a driving signal in response to a control signal of the touch sensing circuit, coupled to one of a first coupling voltage and a second coupling voltage of the touch input device in response to the control signal, and adjusted to an output equivalent capacitance value in response to the control signal so as to compensate at least one of a GND parasitic capacitor and a cross coupling capacitor of the touch input device.

Description

Electronics for Compensating Capacitance Deviations

technical field

The invention relates to an electronic device capable of compensating capacitance deviation.

Background technique

Currently, tactile switches have been developed. The touch switch is, for example, a capacitive switch or the like. For the convenience of use, the touch panel (touch panel) or display touch panel (with both display and touch functions) has been developed at present, which can be input, clicked, etc. by the user, and can be applied to various Among electronic devices, such as mobile phones. In this way, users can directly input or click images on the touch panel or display touch panel, so as to provide a convenient and humanized operation mode. There are many kinds of touch panels or display touch panels, capacitive touch panels and capacitive display touch panels belong to them.

When the user operates the capacitive touch panel, the capacitive display touch panel, or the capacitive switch, the capacitance value of the internal capacitor to be measured will change according to the user's operation. Therefore, if the capacitance value of the capacitor to be measured and its change can be detected, the user's operation can be detected (feeled). The positioning principle of the capacitive touch panel is to determine the position of the touch point by using the change of the capacitance of the sensing grid embedded in the touch panel.

FIG. 1 shows a schematic diagram of a touch panel 10 in the prior art. Please refer to FIG. 1 , the touch panel 10 includes a plurality of X-direction wires (X1˜Xm) and a plurality of Y-direction wires (Y1˜Yn). Both m and n are positive integers, and m and n may be equal or unequal. The wires in the X direction and the wires in the Y direction are embedded in different layers. The wires in the X direction and the wires in the Y direction are arranged alternately to form a sensing grid. A cross-coupling capacitor (such as cross-coupling capacitors 100a, 100b and 100c in FIG. 1) is formed at each intersection of the X-direction wire and the Y-direction wire. Taking FIG. 1 as an example, the touch panel 10 has m*n cross-coupling capacitors in total.

When an object (such as a finger or a stylus) touches the touch panel 10 , the coupling relationship between the object and the sensing grid will change the capacitance of the adjacent cross-coupling capacitors. The detection circuit can detect the variation of the capacitance value of the cross-coupling capacitor to detect the coordinate position of the contact point.

However, if some wires on the touch panel are due to poor workmanship or different shapes of the wires, the parasitic capacitances of the wires to the ground may not be equal to each other, or the cross-coupling capacitances may not be equal to each other (such as , the cross-coupling capacitors 100 a - 100 c are not equal to each other), it is easy to cause misjudgment of the touch position.

Therefore, the present invention provides a capacitance deviation compensation circuit, which can compensate the deviation value of the parasitic capacitance to ground, and/or compensate the deviation value of the cross-coupling capacitance.

Contents of the invention

The invention relates to an electronic device capable of compensating the ground parasitic capacitance deviation and/or cross-coupling capacitance deviation of a touch panel.

An embodiment of the present invention provides an electronic device, including: a touch input device; a touch sensing circuit coupled to the touch input device; and a capacitance deviation compensation circuit. The capacitance deviation compensation circuit includes: a first selector, responsive to a control signal of the touch sensing circuit, to select one of the first coupling voltage and the second coupling voltage of the touch input device; a second selector, responsive to The control signal selects one of the driving signal or the reference voltage; and a first offset compensation capacitor array, coupled to the first selector or the second selector, adjusts the output equivalent capacitance in response to the control signal, so as to At least one of parasitic capacitance to ground and cross-coupling capacitance of the touch input device is compensated.

According to the embodiment of the present invention, in the electronic device, when the first offset compensation capacitor array compensates the ground-to-ground parasitic capacitance of the direction wire of the touch input device, the first selector selects the output of the direction wire The first coupling voltage is output to the first offset compensation capacitor array, and the second selector selects the reference voltage and outputs it to the first offset compensation capacitor array.

According to the embodiment of the present invention, in the electronic device, when the first offset compensation capacitor array compensates the cross-coupling capacitance of the direction wire of the touch input device, the first selector selects the output of the direction wire The first coupling voltage is output to the first offset compensation capacitor array, and the second selector selects the driving signal and is output to the first offset compensation capacitor array.

Another embodiment of the present invention provides an electronic device, including: a touch input device; a touch sensing circuit coupled to the touch input device; and a capacitance deviation compensation circuit. The capacitance deviation compensation circuit includes: a first selector, which selects one of the first coupling voltage and the second coupling voltage of the touch input device in response to a control signal of the touch sensing circuit; a second selector, which responds to the A control signal to select one of the first coupling voltage and the second coupling voltage; the first offset compensation capacitor array is coupled to the first selector and the driving signal, and adjusts the output equivalent capacitance in response to the control signal, to compensate the cross-coupling capacitance of the touch input device; and a second offset compensation capacitor array, coupled to the second selector and the reference voltage, to adjust the output equivalent capacitance in response to the control signal to compensate the touch Parasitic capacitance of the input device to ground.

Another embodiment of the present invention provides an electronic device, including: a touch input device; a touch sensing circuit coupled to the touch input device; and a capacitance deviation compensation circuit. The capacitance deviation compensation circuit includes: a first deviation compensation capacitor array, coupled to a reference voltage or a driving signal in response to a control signal of the touch sensing circuit, and coupled to a first touch input device in response to the control signal One of the first coupling voltage and the second coupling voltage adjusts the output equivalent capacitance in response to the control signal to compensate at least one of the ground parasitic capacitance and the cross-coupling capacitance of the touch input device.

According to the embodiment of the present invention, in the electronic device, the capacitance deviation compensation circuit further includes: a first selector, in response to the control signal, conducting one of the first coupling voltage and the second coupling voltage to the a first offset compensation capacitor array; and a second selector, in response to the control signal, conducting one of the reference voltage and the driving signal to the first offset compensation capacitor array.

Preferably, when the first deviation compensating capacitor array compensates the ground-to-ground parasitic capacitance of the direction wire of the touch input device, the first selector conducts the first coupling voltage output by the direction wire to the first deviation Compensation capacitor array, the second selector conducts the reference voltage to the first offset compensation capacitor array.

Preferably, when the first offset compensation capacitor array compensates the cross-coupling capacitance of the direction wire of the touch input device, the first selector conducts the first coupling voltage output by the direction wire to the first offset compensation Capacitor array, the second selector conducts the driving signal to the first offset compensation capacitor array.

According to an embodiment of the present invention, in the electronic device, the first offset compensation capacitor array is coupled to the drive signal to compensate the cross-coupling capacitor of the touch input device; the capacitor offset compensation circuit further includes: The second offset compensation capacitor array is coupled to the reference voltage to compensate the ground parasitic capacitance of the touch input device; the first selector is used to conduct the first coupling voltage and the second coupling voltage in response to the control signal. coupling one of the voltages to the first offset compensation capacitor array; and a second selector, in response to the control signal, conducting one of the reference voltage and the driving signal to the second offset compensation capacitor array.

In order to make the above content of the present invention more obvious and understandable, the following specific examples are given in conjunction with the accompanying drawings, and are described in detail as follows:

Description of drawings

FIG. 1 shows a schematic diagram of a touch panel in the prior art.

FIG. 2 shows a schematic diagram of an electronic device according to a first embodiment of the present invention.

FIG. 3A shows an equivalent circuit diagram for compensating parasitic capacitance to ground according to the first embodiment of the present invention.

FIG. 3B shows an equivalent circuit diagram of compensating cross-coupling capacitors according to the first embodiment of the present invention.

FIG. 4 shows a schematic diagram of an electronic device according to a second embodiment of the present invention.

Detailed ways

first embodiment

Fig. 2 shows a schematic diagram of an electronic device according to a first embodiment of the present invention. As shown in FIG. 2 , the electronic device 200 includes a touch panel 210 , a driving signal generating circuit 220 , an X-direction driving channel selection module 230 , a Y-direction driving channel selection module 240 , a selection and detection module 250 and a capacitance deviation compensation circuit 260 . The X-direction drive channel selection module 230 , the Y-direction drive channel selection module 240 and the selection and detection module 250 can be regarded as touch sensing circuits.

The driving signal generation circuit 220 is used to generate the driving signal D to the X-direction wires X1-Xm and the Y-direction wires X1-Xn. The driving signal D is, for example but not limited to, a square wave driving signal, a triangular wave driving signal, a sine wave driving signal and the like.

The X-direction driving channel selection module 230 includes m switches, each switch is controlled by an individual control signal generated by the control circuit 2511 , and the m control signals are respectively input to the individual switch through the signal line 232 . Each switch is coupled between the driving signal generating circuit 220 and each corresponding X-direction wire X1˜Xm. The coupled voltages of the wires X1 ˜ Xm in the X direction are respectively input to the selection and detection module 250 through the signal wire 231 .

The Y-direction driving channel selection module 240 includes n switches, each switch is controlled by an individual control signal generated by the control circuit 2511 , and the n control signals are respectively input to the individual switch through the signal line 242 . Each switch is coupled between the driving signal generating circuit 220 and each corresponding Y-direction wire Y1 ˜Yn. The coupled voltages of the wires Y1 -Yn in the Y direction are respectively input to the selection and detection module 250 through the signal wires 241 .

The selection and detection module 250 includes a selection module 251 and a differential detection module 252 . The selection module 251 includes a control circuit 2511 , a first multiplex selector 2512 and a second multiplex selector 2513 . The capacitor offset compensation circuit 260 includes: a third multiplexer 261 , a fourth multiplexer 262 and an offset compensation capacitor array 263 . The offset compensation capacitor array 263 includes a plurality of compensation capacitors.

After the touch panel 210 is manufactured, the touch panel 210 is measured to record the ground parasitic capacitance of the wires in each direction and all cross-coupling capacitances of the panel to determine whether there is capacitance deviation. The capacitance values of these compensation capacitors are related to the deviations of the parasitic capacitances of the wires in each direction to the ground, and the deviations of all the cross-coupling capacitances of the panel.

The operating principle of the first embodiment will now be described. The control circuit 2511 scans (turns on) the switches in sequence. Assume that the user touches the intersection of the direction wires X2 and Y1. Under the control of the control circuit 2511, the corresponding switch is turned on so that the drive signal D is input to the Y-direction wire Y1; moreover, the coupling voltages VY1X1 and VY1X2 are transmitted through the first multiplexer 2512 and the second multiplexer 2513 respectively. Coupled to differential detection module 252 . The coupling voltages VY1X1 and VY1X2 represent the coupling voltages generated by the driving signal D applied to the cross-coupling capacitors CY1X1 and CY1X2 respectively. Then, at the next timing, the driving signal D is still input to the Y-direction wire Y1; and the coupling voltages VY1X2 and VY1X3 are coupled to the differential detection module 252 via the first multiplexer 2512 and the second multiplexer 2513 respectively. Under ideal conditions (ie, no capacitance deviation), the differential detection module 252 will detect VY1X2≠VY1X1 and VY1X2≠VY1X3. Therefore, through the output signal S of the differential detection module 252 , it can be determined that the user touches the intersection of the direction wires X2 and Y1 .

Of course, when detecting the touch position, the control circuit 2511 can also make the driving signal D input to the X-direction wire, and make the coupling voltage of the Y-direction wire be coupled through the first multiplexer 2512 and the second multiplexer 2513 to the differential detection module 252 .

However, in actual situations, the ground parasitic capacitances of the wires may be different from each other, and/or the cross-coupling capacitances may be different from each other. Therefore, how to use the capacitance deviation compensating circuit 260 to compensate the deviation value of the parasitic capacitance to ground and the deviation value of the cross-coupling capacitance in the first embodiment will be respectively described below.

When performing capacitance deviation compensation, under the control of the control circuit 2511, the third multiplex selector 261 connects the output signal of one of the first multiplex selector 2512 or the second multiplex selector 2513 to the offset compensation capacitor array 263 ; the fourth multitasking selector 262 inputs one of the reference voltage source VREF or the driving signal D to the offset compensation capacitor array 263 ; the control circuit 2511 selects an appropriate compensation capacitor in the offset compensation capacitor array 263 .

(1) Compensate the deviation value of the ground parasitic capacitance

Assume that the parasitic capacitance of the wire X2 in the X direction has deviations to the ground. As mentioned above, when the differential detection module 252 compares the coupling voltage VY1X1 (the output signal of the first multiplex selector 2512) and VY1X2 (the output signal of the second multiplex selector 2513), under the control of the control circuit 2511, The third multiplex selector 261 connects the output signal of the second multiplex selector 2513 to the offset compensation capacitor array 263; and the fourth multiplex selector 262 inputs the reference voltage source VREF to the offset compensation capacitor array 263; the control circuit 2511 Appropriate compensation capacitors within the offset compensation capacitor array 263 are selected. The equivalent circuit is shown in Fig. 3A. In FIG. 3A , CX2 represents the parasitic capacitance of the X-direction wire X2 to the ground, and ΔCX2 represents the compensation capacitance for the parasitic capacitance of the X-direction wire X2 to the ground.

For example, there is a correspondence table inside the control circuit 2511 to record whether there is any deviation in the ground parasitic capacitance of the wires in all directions of the touch panel 210 and the corresponding compensation capacitance. When the control circuit 2511 chooses to input the coupling voltage on the directional wire with deviation to the ground parasitic capacitance to the differential detection module 252, the control circuit 2511 will compensate by selecting an appropriate compensation capacitor.

(2) Compensate the offset value of the cross-coupling capacitor

Assume that the cross-coupling capacitance CY1X2 between the X-direction wire X2 and the Y-direction wire Y1 is biased. As mentioned above, when the differential detection module 252 compares the coupling voltage VY1X1 (the output signal of the first multiplex selector 2512) and VY1X2 (the output signal of the second multiplex selector 2513), under the control of the control circuit 2511, The third multiplex selector 261 will connect the output signal of the second multiplex selector 2513 to the offset compensation capacitor array 263; and the fourth multiplex selector 262 will input the driving signal D to the offset compensation capacitor array 263; the control circuit 2511 will select the appropriate compensation capacitor in the offset compensation capacitor array 263 . The equivalent circuit is shown in Fig. 3B. In FIG. 3B , CY1X2 represents the cross-coupling capacitance between the X-direction wire X2 and the Y-direction wire Y1 , and ΔCX2Y1 represents the compensation capacitance for the cross-coupling capacitance CY1X2 .

For example, there is a corresponding table inside the control circuit 2511 , which records whether all cross-coupling capacitors of the touch panel 210 have deviations and the corresponding compensation capacitors. When the control circuit 2511 chooses to input the coupling voltage on the directional wire with a biased cross-coupling capacitor to the differential detection module 252, the control circuit 2511 will compensate by selecting an appropriate compensation capacitor.

In the above example, the parasitic capacitance to ground and the cross-coupling capacitance can be compensated. That is to say, the multiple compensation capacitors inside the offset compensation capacitor array 263 can compensate the parasitic capacitance to ground and the cross-coupling capacitance; however, at any moment, only one of the parasitic capacitance to ground or the cross-coupling capacitance can be compensated for capacitance offset.

However, in other possible examples of the first embodiment of the present invention, only one of the parasitic capacitance to ground or the cross-coupling capacitance is compensated. That is to say, the compensation capacitors inside the offset compensation capacitor array 263 are only used to compensate one of the parasitic capacitance to ground or the cross-coupling capacitance.

second embodiment

FIG. 4 shows a schematic diagram of an electronic device 200A according to a second embodiment of the present invention. Most of the components of the second embodiment of the present invention are the same or similar to those of the first embodiment, so details thereof will not be repeated here.

In the second embodiment of the present invention, the capacitor offset compensation circuit 260A further includes: a first offset compensation capacitor array 263A1 and a second offset compensation capacitor array 263A2 . Each of the first offset compensation capacitor array 263A1 and the second offset compensation capacitor array 263A2 includes a plurality of compensation capacitors. Wherein, the first offset compensation capacitor array 263A1 can compensate all the cross-coupling capacitors of the touch panel 210 , and the second offset compensation capacitor array 263A2 can compensate the ground parasitic capacitance of the wires in each direction.

The operating principle of the second embodiment will now be described. Similarly, when compensating the capacitance deviation value, under the control of the control circuit 2511, the third multiplex selector 261 connects the output signal of one of the first multiplex selector 2512 or the second multiplex selector 2513 to the first The offset compensation capacitor array 263A1; the fourth multiplex selector 262 connects the output signal of one of the first multiplex selector 2512 or the second multiplex selector 2513 to the second offset compensation capacitor array 263A2. The first offset compensation capacitor array 263A1 also receives the driving signal D; and the second offset compensation capacitor array 263A2 also receives the reference voltage VREF. The control circuit 2511 selects an appropriate compensation capacitor in the first offset compensation capacitor array 263A1 and an appropriate compensation capacitor in the second offset compensation capacitor array 263A2. In the second embodiment of the present invention, the parasitic capacitance to ground and the cross-coupling capacitance can be compensated at the same time.

To sum up, although the present invention has been disclosed above with the embodiments, it is not intended to limit the present invention. Those skilled in the technical field of the present invention can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be defined according to the scope of the appended claims.

Explanation of main component symbols

10, 210: touch panel

X1～Xm: wire in X direction

Y1～Yn: Y direction wire

100a, 100b, 100c: cross-coupling capacitors

200, 200A: electronic device

220: Drive signal generating circuit

230: X direction driving channel selection module

240: Y direction drive channel selection module

250: Selection and Detection Module

251: Select module

252: Differential detection module

2511: control circuit

2512, 2513, 261, 262: multitasking selector

260, 260A: capacitance deviation compensation circuit

263, 263A1, 263A2: offset compensation capacitor array

CX2: Parasitic capacitance to ground

CY1X2: Cross-Coupling Capacitors

ΔCX2, ΔCX2Y1: Compensation capacitance.

Claims (9)

1. electronic installation comprises:

Touch-control input device;

Touch control sensing circuit is coupled to described touch-control input device; And

The capacitance deviation compensating circuit comprises:

First selector is selected one of first coupled voltages of described touch-control input device and second coupled voltages in response to the control signal of described touch control sensing circuit;

Second selector is selected one of drive signal or reference voltage in response to described control signal; And

The first deviation compensation capacitor array is coupled to described first selector or described second selector, adjusts the output equivalent capacitance in response to described control signal, with the stray capacitance over the ground that compensates described touch-control input device and cross coupling capacitor one of at least.

2. electronic installation according to claim 1, wherein, when the first deviation compensation capacitor array compensates the described stray capacitance over the ground of direction lead of described touch-control input device, described first selector is selected described first coupled voltages that described direction lead exported and is exported the described first deviation compensation capacitor array to, and described second selector is selected described reference voltage and exported the described first deviation compensation capacitor array to.

3. electronic installation according to claim 1, wherein, when the first deviation compensation capacitor array compensates the described cross coupling capacitor of direction lead of described touch-control input device, described first selector is selected described first coupled voltages that described direction lead exported and is exported the described first deviation compensation capacitor array to, and described second selector is selected described drive signal and exported the described first deviation compensation capacitor array to.

4. electronic installation comprises:

Touch-control input device;

Touch control sensing circuit is coupled to described touch-control input device; And

The capacitance deviation compensating circuit comprises:

First selector is selected one of first coupled voltages of described touch-control input device and second coupled voltages in response to the control signal of described touch control sensing circuit;

Second selector is selected one of described first coupled voltages and described second coupled voltages in response to described control signal;

The first deviation compensation capacitor array is coupled to described first selector and drive signal, adjusts the output equivalent capacitance in response to described control signal, to compensate the cross coupling capacitor of described touch-control input device; And

The second deviation compensation capacitor array is coupled to described second selector and reference voltage, adjusts the output equivalent capacitance in response to described control signal, to compensate the stray capacitance over the ground of described touch-control input device.

5. electronic installation comprises:

Touch-control input device;

Touch control sensing circuit is coupled to described touch-control input device; And

The capacitance deviation compensating circuit comprises:

The first deviation compensation capacitor array, be coupled to reference voltage or drive signal in response to the control signal of described touch control sensing circuit, be coupled to one of first coupled voltages of described touch-control input device and second coupled voltages in response to described control signal, adjust the output equivalent capacitance in response to described control signal, with the stray capacitance over the ground that compensates described touch-control input device and cross coupling capacitor one of at least.

6. electronic installation according to claim 5, wherein, described capacitance deviation compensating circuit also comprises:

First selector, one of described first coupled voltages of conducting and described second coupled voltages are to the described first deviation compensation capacitor array in response to described control signal; And

Second selector, one of the described reference voltage of conducting and described drive signal are to the described first deviation compensation capacitor array in response to described control signal.

7. electronic installation according to claim 6, wherein, when the first deviation compensation capacitor array compensates the described stray capacitance over the ground of direction lead of described touch-control input device, described first coupled voltages that the described direction lead of described first selector conducting is exported is to the described first deviation compensation capacitor array, and the described reference voltage of described second selector conducting is to the described first deviation compensation capacitor array.

8. electronic installation according to claim 6, wherein, when the first deviation compensation capacitor array compensates the described cross coupling capacitor of direction lead of described touch-control input device, described first coupled voltages that the described direction lead of described first selector conducting is exported is to the described first deviation compensation capacitor array, and the described drive signal of described second selector conducting is to the described first deviation compensation capacitor array.

9. electronic installation according to claim 5, wherein,

The described first deviation compensation capacitor array is coupled to described drive signal, to compensate the described cross coupling capacitor of described touch-control input device;

Described capacitance deviation compensating circuit also comprises:

The second deviation compensation capacitor array is coupled to described reference voltage, to compensate the described stray capacitance over the ground of described touch-control input device;

First selector, one of described first coupled voltages of conducting and described second coupled voltages are to the described first deviation compensation capacitor array in response to described control signal; And

Second selector, one of the described reference voltage of conducting and described drive signal are to the described second deviation compensation capacitor array in response to described control signal.

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