KR101120505B1 - Method and apparatus for detecting capacitance in touch sensor - Google Patents

Abstract

The present invention relates to an apparatus and method for measuring capacitance of a touch sensor. In the conventional capacitance measurement technology, the problem of mutual capacitance value not being properly measured by charging sharing, but it is good if the capacitance value of the place to be measured can be known in advance. Since this is not possible, a capacitor of more than a certain size must be implemented. Because of this, it can only be implemented with an external capacitor, and the choice of calculation method with different weights for each panel load is inevitable. Therefore, in the present invention, it is possible to quickly and accurately measure the capacitance change of the panel load of the touch sensor, and to increase the touch sensitivity of the touch sensor, while measuring the capacitance of the touch sensor that is robust to noise. To prepare.

Touch sensor, capacitance, reference voltage

Description

Capacitive measuring device and method of touch sensor {METHOD AND APPARATUS FOR DETECTING CAPACITANCE IN TOUCH SENSOR}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for measuring capacitance of a touch sensor, and more particularly, to an apparatus and method for measuring a capacitance of a touch sensor suitable for measuring accurate capacitance change in a short time.

In a touch sensor, the capacitance is determined by the contact of a capacitor or an equivalent material or human body with an electrical element connected to the electrode. In this case, the human body may not only directly contact a finger or a specific part of the body with the electrode PAD, but even if the human body does not directly contact the electrode PAD, the electrode PAD may be approached at an unspecified distance. It can be seen that a fine capacitance component is formed between the body and the human body.

In addition, the capacitance changes according to the change of the distance between the adjacent body part and the electrode, which is measured as a result that the capacitance increases as the distance between the electrode and the body gets closer and the capacitance decreases as the distance goes away. .

As such, the distance between the electrode and the human body can be determined to a certain level by measuring the change in capacitance generated by the change of the distance between the electrode and the body part, and the value of a specific critical capacitance is set using the result of the determination. After that, if the capacitance component measured from the electrode is larger than the threshold value, it is determined that the switch is in contact, otherwise it is determined that the switch is non-contact.

The threshold value is determined by experimentally calculating the initial measured value when no contact is made at the power-on time of the touch sensor and the value changed by the surrounding environment, and then subtracting the value from the initial measured value. This is the general way.

In this way, a semiconductor product is a touch sensor IC. Currently, touch sensor ICs are used in many electronic products (mobile phones, TVs, washing machines, air conditioners, microwave ovens, etc.) instead of mechanical switches used in various electronic products.

However, in the touch sensor IC, since the capacitance formed between the electrode and the human body is only a few pF (picofarad) to several tens of pF, various techniques for calculating and measuring this have been proposed.

As part of the conventional capacitance measurement technique, the electrode PAD is completely discharged to ground using an electrical switch, and then the capacitor component of the capacitance generated by the electrode and the human body is charged from the constant current source connected to the voltage to the reference voltage. There is a technique of measuring the value of the capacitance by the value of the timer by measuring the time required by the timer (timer) using a high speed clock (count clock).

This conventional technique has a relatively short time when discharging due to the limitation of the high-speed clock used for measuring capacitance, and a current source that supplies very small current to obtain a sufficient timer value during charging. (current source)

In this way, the smaller the current value is, the more time can be obtained by measuring more timer values. On the other hand, if the current used for charging is too small, the effect on external noise and touch sensor Since the influence of parasitic current inside the semiconductor increases, the amount of change in the time required for charging tends to increase or decrease due to the noise component, and thus, many problems may occur in charging the capacitance efficiently.

As another technique for measuring the capacitance of a conventional touch sensor, the electrode PAD is fully charged to VDD using an electrical switch, and then the capacitance generated by the electrode and the human body through a resistor connected to the ground GND. The time taken to discharge the capacitor component to the reference voltage was measured by a timer using a high speed clock, and the value of the capacitance was measured by the timer value.

This conventional technology also, due to the limitation of the high-speed clock used for measuring capacitance, completes charging in a relatively short time during fast charging, and connects a fairly large resistance of MEGA OHM or more to obtain a sufficient value during discharge. Use it. In this case, in general, when the charge charged in the capacitor is discharged through the resistor, the discharge current uses a fine current of several hundred pA to several uA.

However, in the conventional art, the capacitance obtained between the human finger and the electrode is generally only a few pF to several tens of pF, so as the value of the current to discharge is reduced, more charging time is required, so more timer value is obtained. On the other hand, if the current used to charge is too small, the influence of external noise and parasitic current inside the touch sensor semiconductor increases, so the amount of change in charging time is noisy. Because of the tendency to increase or decrease by the components, many problems arise in measuring the time taken to efficiently charge the capacitance.

In addition, in the conventional capacitance measurement technology, there is a problem in that mutual capacitance values are not properly measured due to charging sharing. That's fine, but you can't, so you'll need to implement a capacitor of a certain size.

Because of this, it can only be implemented with an external capacitor, and the choice of calculation method with different weights for each panel load is inevitable.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described conventional situation, and aims to provide a technology for measuring capacitance of a touch sensor that can quickly and accurately measure capacitance change of a panel load of a touch sensor.

In addition, the present invention, to increase the touch sensitivity of the touch sensor to provide a technology for measuring the capacitance of the touch sensor due to the noise (noise).

According to an apparatus for measuring capacitance of a touch sensor for solving the problems of the present invention, a first OP amplifier providing a panel driving voltage for driving a panel rod to the panel rod, and the panel driving A reference voltage input unit configured to generate a reference voltage changed from a reference voltage to a preset level according to the panel load voltage generated in response to the operation of the panel load by a voltage, and a second OP amplifier converting the panel load voltage into a monitoring voltage And generating a capacitance measurement result by comparing the monitoring voltage converted through the second OP amplifier with a reference voltage changed to the preset level, and outputting an output voltage according to the generated capacitance measurement result. It may include a third OP amplifier applied to the OP amplifier.

Here, the reference voltage input unit may input the reference voltage changed to the preset level to the third OP amplifier as the panel load voltage transitions to a high level or a low level.

The reference voltage input unit may generate a reference voltage down from the reference voltage to the predetermined level when the panel load voltage transitions from the low level to the high level and input the generated reference voltage to the third OP amplifier. can do.

The third OP amplifier may shift the output voltage from the high level to the low level.

The reference voltage input unit may generate a reference voltage up from the reference voltage to the predetermined level when the panel load voltage is transitioned from the high level to the low level, and input the generated reference voltage to the third OP amplifier. can do.

The third OP amplifier may shift the output voltage from the low level to the high level.

The first OP amplifier may be a panel driving buffer.

The second OP amplifier may be a voltage conversion amplifier.

The third OP amplifier may be a comparator.

In addition, the capacitance measuring device of the touch sensor may include a current detection voltage conversion circuit.

In addition, the panel load may transition to a high level or a low level according to the panel driving signal of the panel driving buffer.

In addition, the panel rod may be a panel rod that charges / discharges mutual capacitance.

The capacitance measuring apparatus may further include a monitoring resistor connected in parallel with the input / output terminal of the second OP amplifier to detect a current induced by the change of the mutual capacitance of the panel load.

In addition, the capacitive measuring device of the touch sensor, the monitoring charge of the panel load may be moved to the monitoring resistor when the potential of the panel load transitions from the low level to the high level.

The capacitive measuring device of the touch sensor may move the monitoring charge from the monitoring resistor to the panel load when the panel load transitions from the high level to the low level.

According to the capacitive detection method of the touch sensor for solving the problems of the present invention, a) converting the panel load voltage according to the operation of the panel load to a monitoring voltage, and b) when the potential level of the panel rod is transitioned Converting the reference voltage, which is a reference for capacitance measurement of the panel load, to a reference voltage changed to a preset level, and c) comparing the converted monitoring voltage with the preset level converted reference voltage according to a comparison result. Generating an output voltage; and d) translating a potential level of the panel rod according to the generated output voltage.

Here, the process b) may be characterized in that the reference voltage is converted into a reference voltage changed to the preset level as the potential level of the panel rod transitions to a high level or a low level.

In addition, the process b) may generate a reference voltage down from the reference voltage to the predetermined level when the potential level of the panel rod is changed from the low level to the high level.

In addition, the process b) may generate a reference voltage up from the reference voltage to the preset level when the panel load voltage transitions from the high level to the low level.

In addition, in the capacitance measuring method of the touch sensor, the monitoring charge of the panel load may be moved from the panel load when the potential of the panel load voltage transitions from the low level to the high level.

In addition, in the capacitive measurement method of the touch sensor, the monitoring charge may be moved to the panel load when the potential of the panel load voltage transitions from the high level to the low level.

According to the present invention, the amount of charge and discharge of the touch sensor can be adjusted with a monitoring resistor to accurately detect a change in the capacitance value of the panel load, thereby increasing the touch sensitivity and implementing a circuit. It is possible to simplify the operation and increase the data processing speed while providing robustness against noise.

The basic operation of the touch sensor is to detect the amount of change in the panel load capacitance caused by the touch operation. Since the conventional sensing techniques cannot extract an accurate sensing value in the sensing process, the sensing technique is performed with an approximate value. This adds significant complexity to the implementation circuitry and poses a challenge to consider options depending on the panel load size.

In the present invention, to propose a technique that can accurately measure the capacitance value of the panel load.

In the present invention, since the capacitance value of the panel can be accurately measured when driving at a predetermined level regardless of the size of the panel load, the output value is linearly measured by how much touch is made when the touch is made. can do.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, and only the embodiments make the disclosure of the present invention complete, and the general knowledge in the art to which the present invention belongs. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims. Like numbers refer to like elements throughout.

In describing the embodiments of the present invention, if it is determined that a detailed description of a known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, terms to be described below are terms defined in consideration of functions in the embodiments of the present invention, which may vary according to intentions or customs of users and operators. Therefore, the definition should be based on the contents throughout this specification.

Combinations of each block of the accompanying block diagram and each step of the flowchart may be performed by computer program instructions. These computer program instructions may be mounted on a processor of a general purpose computer, special purpose computer, or other programmable data processing equipment such that the instructions performed through the processor of the computer or other programmable data processing equipment may be used in each block or flowchart of the block diagram. It will create means for performing the functions described in each step of. These computer program instructions may be stored in a computer usable or computer readable memory that can be directed to a computer or other programmable data processing equipment to implement functionality in a particular manner, and thus the computer usable or computer readable memory. It is also possible for the instructions stored in to produce an article of manufacture containing instruction means for performing the functions described in each block or flowchart of each step of the block diagram. Computer program instructions may also be mounted on a computer or other programmable data processing equipment, such that a series of operating steps may be performed on the computer or other programmable data processing equipment to create a computer-implemented process to create a computer or other programmable data. Instructions that perform processing equipment may also provide steps for performing the functions described in each block of the block diagram and in each step of the flowchart.

In addition, each block or step may represent a portion of a module, segment or code that includes one or more executable instructions for executing a specified logical function (s). It should also be noted that in some alternative embodiments, the functions noted in the blocks or steps may occur out of order. For example, the two blocks or steps shown in succession may in fact be executed substantially concurrently, or the blocks or steps may sometimes be performed in the reverse order, depending on the functionality involved.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic block diagram of an apparatus for measuring capacitance of a touch sensor according to an exemplary embodiment of the present invention, which is a panel driver 100 and a panel load 200. It can be composed of).

Here, the panel driver 100 includes the current detection voltage conversion circuit according to the present embodiment, and applies a panel driving voltage to the panel rod 200 to drive the panel rod 200, and the panel rod 200. A function of detecting a current induced by a change in capacitance of the panel rod 200 according to the panel load voltage generated through the panel load voltage, and changing the reference voltage required to measure the capacitance of the panel load 200 to a predetermined level. Can be performed.

In detail, the panel driver 100 corresponds to a first OP amplifier 10 providing a panel driving voltage for driving the panel rod 200 to the panel rod 200 and an operation of the panel rod by the panel driving voltage. A reference voltage input unit 12 for generating a reference voltage VTref changed from the reference voltage Vref to a preset level according to the panel load voltage generated by the control panel, and a second OP for converting the panel load voltage into a monitoring voltage VM. The amplifier 14 and the monitoring voltage VM converted through the second OP amplifier 14 and the reference voltage VTref changed to a preset level are compared with each other to generate a capacitance measurement result, and the generated capacitance It may include a third OP amplifier 16 for applying the output voltage according to the measurement result to the first OP amplifier 10.

Here, the first OP amplifier 10 may serve to drive the panel load 200 according to the output voltage of the third amplifier 16, for example, as a panel driving buffer.

The reference voltage input unit 12 according to the present exemplary embodiment may include the reference voltage VTref changed to a preset level as the panel load voltage transitions to a high level or a low level. It can serve as input.

In detail, when the panel load voltage transitions from the low level to the high level, the reference voltage input unit 16 generates a reference voltage VTref that is down from the reference voltage Verf to a preset level to generate a third voltage. Input to the OP amplifier 16 is possible. At this time, the third OP amplifier 16 may, for example, as a comparator, transition the output voltage provided to the first OP amplifier 10 from a high level to a low level.

In addition, when the panel load voltage transitions from the high level to the low level, the reference voltage input unit 16 generates a reference voltage VTref up from the reference voltage Vtef to a preset level to generate a third OP. Input to amplifier 16 is possible. In this case, the third OP amplifier 16 as a comparator may shift the output voltage provided to the first OP amplifier 10 from a low level to a high level.

The second OP amplifier 14 may be a voltage conversion amplifier, for example, and may convert a panel load voltage induced by the panel load 200 into a monitoring voltage VM.

A monitoring resistor RM for detecting a current induced by a change in mutual capacitance of the panel rod 200 may be connected to an input / output terminal of the second OP amplifier 14 in parallel.

In the capacitive measuring device of the touch sensor according to the present embodiment, when the potential of the panel load 200 transitions from the low level to the high level, the monitoring charge QM of the panel load 200 is transferred to the monitoring resistor RM. It is characterized in that it is moved.

In addition, in the capacitance measuring device of the touch sensor according to the present embodiment, when the potential of the panel load 200 transitions from the high level to the low level, the monitoring charge QM is changed from the monitoring resistor RM to the panel load 200. It is characterized by being moved to).

The panel load 200 may transition to a high or low level according to a panel driving signal of the first OP amplifier 10, which is a panel driving buffer. The panel load 200 may have mutual power failure as described above. As a capacitive panel load, a mutual capacitance capacitor CM, for example, a first load capacitor CL1 and a first load resistor RL1, which can be located on the upper plate of the panel rod 200, and a panel rod 200 ) May include a second load capacitor CL2, a second load resistor RL2, and the like.

Hereinafter, with reference to the above-described configuration, with reference to Figures 2 to 6 attached to the capacitance measuring method of the touch sensor according to an embodiment of the present invention will be described.

In the capacitance measuring method of the touch sensor according to the present exemplary embodiment, a process of converting the panel load voltage according to the operation of the panel load 200 into a monitoring voltage VM, and a potential level of the panel load 200 may be transitioned. Converting the reference voltage (Vref), which is the reference for the capacitance measurement of the panel load, to the reference voltage (VTref) changed to the preset level, and the converted monitoring voltage (VM) and the preset level converted reference voltage (VTref). ) And a process of generating an output voltage according to the comparison result, and a process of shifting the potential level of the panel load 200 according to the generated output voltage.

Here, the process of converting the reference voltage VTref changed to the preset level may include changing the reference voltage Vref to the preset level as the potential level of the panel load 200 transitions to the high level or the low level. VTref).

In addition, the process of converting the reference voltage VTref changed to the preset level may include the reference voltage down from the reference voltage Vref to the preset level when the potential level of the panel load 200 transitions from the low level to the high level. (VTref) may be characterized by generating.

In addition, the process of converting the reference voltage VTref changed to the preset level may include the reference voltage VTref up from the reference voltage Vref to the preset level when the panel load voltage transitions from the high level to the low level. ) May be generated.

In addition, in the capacitance measuring method of the touch sensor according to the present embodiment, the monitoring charge QM of the panel load 200 may be moved from the panel load when the potential of the panel load voltage transitions from the low level to the high level. .

In addition, in the capacitive measurement method of the touch sensor according to the present exemplary embodiment, the monitoring charge QM may be moved to the panel load 200 when the potential of the panel load voltage transitions from the high level to the low level.

First, FIG. 2 illustrates a method of measuring capacitance of a touch sensor according to an embodiment of the present invention, specifically, a driving process when a panel load transitions from a low level to a high level.

As illustrated in FIG. 2, assuming that the panel load 200 is transitioned from the low level to the high level by the panel driver 100, for example, it is assumed that the panel load 200 is driven from the 0 V to the power supply voltage VDD. In this case, a charge equal to the monitoring charge QM (VDD × CM) may flow into the monitoring resistor RM.

At this time, the panel load voltage VA is converged to the reference voltage Vref by the second OP amplifier 14, which is a voltage conversion amplifier, and for this purpose, charge as much as the monitoring charge QM is drawn out through the monitoring resistor RM. Will go out.

While the monitoring charge QM flows through the monitoring resistor RM, the monitoring voltage VM is brought to a potential drop by the IR drop, which causes the monitoring charge QM to be all from the monitoring resistor RM. As it exits, the flow of charge disappears and thus may be equal to the panel load voltage (VA).

If the above-described reference voltage Vref is changed to a predetermined level lower reference voltage VTref during this operation, the output voltage of the comparator 16 transitions from the high level to the low level.

FIG. 3 is a waveform diagram illustrating a reference voltage Vref and a constant level low reference voltage VTref during the driving process of FIG. 2.

In FIG. 3, the thick solid line represents the monitoring voltage VM, the dotted line represents the existing reference voltage Vref, and the thin solid line represents the reference level VTref that can be applied to the present embodiment.

4 is a diagram illustrating a method of measuring capacitance of a touch sensor according to an embodiment of the present invention, specifically, a driving process when a potential of a panel load transitions from a high level to a low level.

As illustrated in FIG. 4, assuming that the panel load 200 is transitioned from the high level to the low level by the panel driver 100, for example, it is assumed that the panel load 200 is driven from 0 V at the power supply voltage VDD. In this case, a charge equal to the monitoring charge QM (VDD × CM) may flow out from the monitoring resistor RM.

At this time, the panel load voltage VA is converged to the reference voltage Vref by the second OP amplifier 14, which is a voltage conversion amplifier, and for this purpose, charge as much as the monitoring charge QM is drawn out through the monitoring resistor RM. Will go out.

While the monitoring charge QM flows through the monitoring resistor RM, the monitoring voltage VM rises in potential by an IR drop, which causes the monitoring charge QM to escape all from the monitoring resistor RM. In this case, since the flow of charge disappears, it may be equal to the panel load voltage VA.

If the above-mentioned reference voltage Vref is changed to a certain level higher reference voltage VTref during this operation, the output voltage of the comparator 16 transitions from the low level to the high level.

FIG. 5 is a waveform diagram illustrating a reference voltage Vref and a predetermined level high reference voltage VTref during the driving process of FIG. 4.

In FIG. 5, the thick solid line represents the monitoring voltage VM, the dotted line represents the existing reference voltage Vref, and the thin solid line represents the reference level VTref that can be applied to the present embodiment.

6 is a waveform diagram illustrating a monitoring voltage VM, a reference voltage Vref, a modified reference voltage VTref, a panel clock, a reference clock, and the like applied to the present embodiment.

As the driving process of FIGS. 2 and 4 is repeated, a clock having a frequency in which the output voltage of the first OP amplifier 10 which is the panel driving buffer is inversely proportional to the capacitance value of the mutual capacitance capacitor CM can be obtained. Since the capacitance value of the mutual capacitance capacitor changes according to before and after the touch of the touch sensor, it is possible to detect a change in the count of the reference clock.

As described above, in the present embodiment, the charge amount and the discharge amount of the touch sensor can be adjusted by the monitoring resistor RM to accurately detect the change in the capacitance value of the panel load. In addition, it can realize fast and accurate measurement of capacitance change of panel load of touch sensor.

1 is a block diagram illustrating an apparatus for measuring capacitance of a touch sensor according to an embodiment of the present invention;

FIG. 2 is a view illustrating a capacitance measuring method of a touch sensor according to an exemplary embodiment of the present invention, illustrating a driving process when a potential of a panel rod transitions from a low level to a high level. ,

3 is a waveform diagram illustrating a reference voltage Vref and a reference voltage VTref down to a predetermined level during the driving process of FIG. 2;

4 is a view illustrating a capacitance measuring method of a touch sensor according to an exemplary embodiment of the present invention, and illustrates a driving process when a potential of a panel load transitions from a high level to a low level is illustrated. ,

5 is a waveform diagram illustrating a reference voltage Vref and a reference voltage VTref down to a predetermined level during the driving process of FIG. 4;

6 is a waveform diagram illustrating a monitoring voltage VM, a reference voltage Vref, a modified reference voltage VTref, a panel clock, a reference clock, and the like applied to the present embodiment.

<Explanation of symbols for the main parts of the drawings>

100: panel drive unit

200: panel load

10: voltage conversion amplifier

12: comparator

14: panel drive buffer

16: reference voltage input unit

Claims (21)

A first OP amplifier providing a panel driving voltage for driving the panel rod to the panel rod; A reference voltage input unit configured to generate a reference voltage changed from a reference voltage to a preset level according to the panel load voltage generated in response to the operation of the panel load by the panel driving voltage; A second OP amplifier converting the panel load voltage into a monitoring voltage; Comparing the monitoring voltage converted through the second OP amplifier and the reference voltage changed to the preset level to generate a capacitance measurement result, and outputs an output voltage according to the generated capacitance measurement result to the first OP amplifier. To apply a third OP amplifier Capacitive measurement device of the touch sensor comprising a. The method of claim 1, The reference voltage input unit may input a reference voltage changed to the preset level to the third OP amplifier as the panel load voltage transitions to a high level or a low level. Capacitive measuring device of touch sensor. The method of claim 2, The reference voltage input unit may generate a reference voltage which is down from the reference voltage to the predetermined level when the panel load voltage transitions from the low level to the high level to generate the third voltage. Input with OP amplifier Capacitive measuring device of touch sensor. The method of claim 3, wherein The third op amp causes the output voltage to transition from the high level to the low level. Capacitive measuring device of touch sensor. The method of claim 2, The reference voltage input unit generates the reference voltage up from the reference voltage to the predetermined level when the panel load voltage transitions from the high level to the low level. Input with OP amplifier Capacitive measuring device of touch sensor. The method of claim 5, The third op amp causes the output voltage to transition from the low level to the high level. Capacitive measuring device of touch sensor. 7. The method according to any one of claims 1 to 6, The first OP amplifier is a panel driving buffer. Capacitive measuring device of touch sensor. 7. The method according to any one of claims 1 to 6, The second OP amplifier is a voltage conversion amplifier. Capacitive measuring device of touch sensor. 7. The method according to any one of claims 1 to 6, The third OP amplifier is a comparator Capacitive measuring device of touch sensor. 7. The method according to any one of claims 1 to 6, The capacitive measuring device of the touch sensor includes a current detection voltage conversion circuit. Capacitive measuring device of touch sensor. The method of claim 1, The panel load has a potential transitioned to a high level or a low level according to a panel driving signal of the panel driving buffer. Capacitive measuring device of touch sensor. The method according to claim 1 or 11, wherein The panel rod is a panel rod that charges / discharges mutual capacitance. Capacitive measuring device of touch sensor. 13. The method of claim 12, The capacitance measuring device, And a monitoring resistor connected in parallel with an input / output terminal of the second OP amplifier to detect a current induced by the change of the mutual capacitance of the panel load. Capacitive measuring device of touch sensor. The method of claim 13, In the capacitive measuring device of the touch sensor, the monitoring charge of the panel load is moved to the monitoring resistor when the panel load transitions from the low level to the high level. Capacitive measuring device of touch sensor. The method of claim 14, In the capacitive measuring device of the touch sensor, the monitoring charge is moved from the monitoring resistor to the panel load when the potential of the panel load transitions from the high level to the low level. Capacitive measuring device of touch sensor. a) converting the panel load voltage according to the operation of the panel load into a monitoring voltage; b) converting a reference voltage, which is a reference for capacitance measurement of the panel rod, into a reference voltage changed to a preset level when the potential level of the panel rod is changed; c) comparing the converted monitoring voltage with the preset level converted reference voltage to generate an output voltage according to a comparison result; d) transitioning the potential level of the panel rod in accordance with the output voltage generated Capacitance measurement method of a touch sensor comprising a. The method of claim 16, The process b) converts the reference voltage into a reference voltage changed to the preset level as the potential level of the panel rod is shifted to a high level or a low level. How to measure capacitance of touch sensor. The method of claim 17, The process b) includes generating a reference voltage that is down from the reference voltage to the predetermined level when the potential level of the panel rod is transitioned from the low level to the high level. Characterized How to measure capacitance of touch sensor. The method of claim 17, In the process b), when the panel load voltage is transitioned from the high level to the low level, the reference voltage is generated from the reference voltage to the predetermined level. doing How to measure capacitance of touch sensor. The method according to any one of claims 17 to 19, In the capacitive measurement method of the touch sensor, a monitoring charge of the panel load is moved from the panel load when the panel load voltage is shifted from the low level to the high level. How to measure capacitance of touch sensor. The method of claim 20, In the capacitive measurement method of the touch sensor, the monitoring charge is transferred to the panel load when the potential of the panel load voltage transitions from the high level to the low level. How to measure capacitance of touch sensor.

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