KR101765443B1 - Touch sensing system having improved sensing performance - Google Patents

Abstract

Disclosed is a touch sensing system with improved sensing performance. The touch sensing system includes: a sensing capacitor including a driving electrode and a sensing electrode, and having the driving electrode coupled with a driving signal; a sensing line electrically connected with the sensing electrode of the sensing capacitor; a compensation capacitor having a terminal electrically connected with the sensing line, and having the other terminal coupled with a compensation signal; a charge accumulator formed between the sensing line and a charge accumulation line, accumulating charges of the sensing line, and driving the charge accumulation line in accordance with a level of the accumulated charges; a multi-sampling holding part generating a first sampling voltage by sampling and holding a voltage level of the charge accumulation line at a first sensing timing, and generating a second sampling voltage by sampling and holding a voltage level of the charge accumulation line at a second sensing timing; an analogue-digital conversion part converting a voltage difference between the first and second sampling voltages into digital decoding data; and a control part providing the driving signal and the compensation signal, having the driving signal activated at the first sensing timing and inactivated at the second sensing timing, and having the compensation signal inactivated at the first sensing timing and activated at the second sensing timing. According to the present invention, the touch sensing system is capable of improving sensing performance.

Description

TECHNICAL FIELD [0001] The present invention relates to a touch sensing system having improved sensing performance,

The present invention relates to a touch sensing system, and more particularly, to a touch sensing system with improved sensing performance.

Due to the convenience of use, the touch sensing system is widely used as a data input device in not only notebook computers, but also household and portable devices or household appliances. In the touch sensing system used as a data input device, the sensing capacitors are arranged in a matrix structure at a constant position on the recognition panel. In a touch sensing system used as a data input device, a sensing signal of an analog component is generated by sensing a position on a recognition panel of a sensing capacitor in which a finger is touched.

Then, the read block of the touch sensing system reads the sensing signal of the analog component provided from the recognition panel to generate the read data of the digital component.

The touch sensing system identifies the sensing capacitors to which the finger is touched through the data value of such read data, and recognizes the user's input from the position of the sensing capacitor whose contact is confirmed.

Also, the touch sensing system is widely used in fingerprint recognition devices. And the touch sensing system senses whether the portion of the finger contacting the sensing capacitor of the recognition panel is a ridge or a valley.

At this time, a sensing signal of an analog component having a level corresponding to a portion of the finger contacting the sensing capacitor is generated. And, similarly to the data input device, the read block of the touch sensing system reads the voltage level of the sensing signal of the analog component provided from the recognition panel and is generated as read data of the digital component.

At this time, the part of the finger is confirmed through the data value of the read data, and the fingerprint of the finger is recognized as a whole.

In the case of the touch sensing system used as such a fingerprint recognition device, it is required to read the voltage level of the sensing signal more accurately in order to accurately recognize the fingerprint of the finger.

An object of the present invention is to provide a touch sensing system with improved sensing performance capable of accurately reading a voltage level of a sensing signal.

According to an aspect of the present invention, there is provided a touch sensing system. According to an aspect of the present invention, there is provided a touch sensing system including a sensing capacitor including a driving electrode and a sensing electrode, the sensing electrode being coupled to a driving signal, ; A sensing line electrically connected to the sensing electrode of the sensing capacitor; A compensation capacitor electrically coupled to the sensing line at one terminal and coupled to the compensation signal at the other terminal; A charge accumulator formed between the sensing line and the charge accumulation line, the charge accumulator integrating the charges of the sensing line and driving the charge accumulation line to a level corresponding to the accumulated charge; Sampling and holding a voltage level of the charge accumulation line at a first sensing timing to generate a first sampling voltage and a voltage level of the charge accumulation line at a second sensing timing to generate a second sampling voltage, part; An analog-to-digital converter converting the voltage difference between the first sampling voltage and the second sampling voltage into read data of a digital component; And a controller for providing the drive signal and the compensation signal to at least partially cancel the effect of coupling the sense capacitor to the sensing line and the coupling capacitor of the compensation capacitor to the sensing line, , The driving signal is activated at the first sensing timing and deactivated at the second sensing timing, and the compensation signal is deactivated at the first sensing timing and activated at the second sensing timing.

According to another aspect of the present invention, there is provided a touch sensing system. According to another aspect of the present invention, there is provided a touch sensing system including a sensing capacitor including a driving electrode and a sensing electrode, the sensing electrode being coupled to a driving signal, A capacitor; A sensing line electrically connected to the sensing electrode of the sensing capacitor; A compensation capacitor electrically coupled to the sensing line at one terminal and coupled to the compensation signal at the other terminal; A charge accumulator formed between the sensing line and the charge accumulation line, the charge accumulator integrating the charges of the sensing line and driving the charge accumulation line to a level corresponding to the accumulated charge; The charge of the spare line is accumulated in the first sampling integration line at the first sensing timing and the charge is accumulated in the first sampling integration line at the second sensing timing and the charge of the spare line is accumulated at the second sensing timing, A multisampling integrated circuit comprising: a multisampling integrated circuit having an integrated voltage; An analog-to-digital converter converting the voltage difference between the first sampling integrated voltage and the second sampling integrated voltage into read data of a digital component; And a controller for providing the drive signal and the compensation signal to at least partially cancel the effect of coupling the sense capacitor to the sensing line and the coupling capacitor of the compensation capacitor to the sensing line, , The driving signal is activated at the first sensing timing and deactivated at the second sensing timing, and the compensation signal is deactivated at the first sensing timing and activated at the second sensing timing.

In the touch sensing system of the present invention configured as described above, the voltage difference / first sampling integrated voltage VSCA1 between the first sampling voltage and the second sampling voltage recognized by the analog-to-digital converter and the second sampling integrated voltage VSCA2 The sensing performance of the touch sensing system of the present invention is greatly improved.

A brief description of each drawing used in the present invention is provided.
FIG. 1 is a diagram showing an electric field between two electrodes when no object enters the sensing area. FIG.
2 is a diagram showing an electric field between two electrodes when an object is present in the sensing area.
3 is a diagram illustrating a touch sensing system according to a first embodiment of the present invention.
4 is a timing chart for explaining an example of the operation of the touch sensing system of FIG.
5 is a diagram illustrating a touch sensing system according to a second embodiment of the present invention.
6 is a timing chart for explaining an example of the operation of the touch sensing system of Fig.
FIG. 7 is a diagram for explaining that the voltage difference of the second sampling integrated voltage with respect to the first sampling integrated voltage in the touch sensing system of FIG. 5 may be negative (-).

For a better understanding of the present invention and its operational advantages, and the objects attained by the practice of the present invention, reference should be made to the accompanying drawings, which illustrate preferred embodiments of the invention, and the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are being provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art.

In describing the contents of the present invention throughout the specification, the meaning of the terms 'electrically connected' and 'connected' among individual components is not limited to direct connection, And the like. The term "provided" for an individual signal also includes not only a direct meaning, but also an indirect meaning through an intermediate medium while maintaining the signal property to a certain extent or more.

Before describing embodiments of the present invention in detail, a change in capacitive coupling of a sensing capacitor caused by a finger to be contacted will be described.

Fig. 1 shows the electric field between two electrodes when no finger is present in the sensing area of the sensing capacitor, Fig. 2 shows the electric field between the two electrodes when the user's finger is in the sensing area of the sensing capacitor Fig. In Figures 1 and 2, for simplicity, only two electrodes 10, 20 are shown forming a sense capacitor.

1, all the electric lines of force formed between the two electrodes 10 and 20 are connected to the two electrodes 10 and 20 when the finger is not present in the sensing area of the sensing capacitor (CASE1). However, when the user's finger 30 enters the sensing area of the sensing capacitor CASE2 as shown in FIG. 2, a part of the electric force line formed between the two electrodes 10 and 20 is grounded via the finger 30, And only the remaining electric lines of force are connected to the electrodes 10 and 20. [

Thus, when the finger 30 of the user is present in the sensing area, the amount of electric charge stored between the electrodes 10, 20 is reduced compared to the case where no object enters the sensing area. Particularly, when applied to a fingerprint recognition device, the reduction width becomes larger when the finger touches the sensing capacitor than when the finger is a ridge.

Using this principle, a constant waveform such as the driving signal XDR is applied to one electrode 10, and at this time, a change in the amount of charge accumulated is measured to determine whether or not a finger is present in the sensing area of the charge- It is possible to detect the part of the finger which is being detected.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First Embodiment

3 is a diagram illustrating a touch sensing system according to a first embodiment of the present invention. 3, the touch sensing system of the first embodiment includes a sense capacitor CPSA, a sensing line LSEN, a compensation capacitor CPCM, a charge integration unit 100, a multisampling and holding unit 200, (300) and a control unit (400).

The sensing capacitor CPSA is disposed in a sensing panel CONPAN and includes a sensing line LSEN, a compensation capacitor CPCM, a charge integration unit 100, a multisampling and holding unit 200, 300 and control unit 400 may be placed in the read block BKRD.

Also, a plurality of the sense capacitors CPSA may be arranged in the recognition panel CONPAN. However, in the present specification, for simplicity of description, only one sense capacitor (CPSA) is representatively shown and described. However, this is merely for convenience of explanation, and the technical idea of the present invention is not limited thereto.

The sensing capacitor CPSA includes a driving electrode EDR and a sensing electrode EDT. The driving electrode EDR is coupled to the driving signal XDR. A dielectric may be formed between the driving electrode EDR and the sensing electrode EDT so that the sensing electrode EDT is capacitively coupled to the driving electrode EDR. Accordingly, the induced charge corresponding to the driving signal XDR applied to the driving electrode EDR is stored in the sensing capacitor CPSA.

 Here, the sense capacitor CPSA has a specific capacitance. However, the capacitance of the sense capacitor CPSA is reduced as the finger contacts. A difference in the amount of change of the substantial capacitances of the sense capacitor CPSA occurs depending on the degree of contact of an object such as a finger and whether the finger is in contact with a ridge or a valley.

As a result, the sensing electrode EDT, which is one terminal of the sensing capacitor CPSA, has a voltage level that is differentiated depending on the degree of contact of the finger, the portion thereof, and the like.

The sensing line LSEN is electrically connected to the sensing electrode EDT of the sense capacitor CPSA. Accordingly, the sensing signal XSEN provided to the sensing line LSEN may be a voltage level of the sensing electrode EDT, and ultimately a level corresponding to the amount of charge stored in the sense capacitor CPSA I have.

In other words, the sensing signal XSEN has a voltage level that is differentiated according to the degree of contact of the finger and the portion thereof.

One terminal of the compensation capacitor CPCM is electrically connected to the sensing line LSEN and the other terminal is coupled to the compensation signal XCM.

At this time, the compensation capacitor CPCM has a capacitance corresponding to the inherent capacitance of the sense capacitor CPSA. Preferably, the compensation capacitor CPCM has the same capacitance as the inherent capacitance of the sense capacitor CPSA.

The charge accumulation unit 100 is formed between the sensing line LSEN and the charge accumulation line LCA and generates a voltage level corresponding to the charge received at the sensing line LSEN in the charge accumulation line LCA do. The charge integrating unit 100 is driven to reset the sensing line LSEN and the charge integrating line LCA in response to the activation of the reset signal RST.

According to a preferred embodiment, the charge accumulation unit 100 includes a charge capacitor 110, a reset switch 130, and an integrated amplifier 150.

The storage capacitor 110 is formed between the sensing line LSEN and the charge accumulation line LCA.

The reset switch 130 is driven to electrically connect the sensing line LSEN and the charge accumulation line LCA in response to the activation of the reset signal RST. At this time, the sensing line LSEN and the charge accumulation line LCA are reset to the reference voltage VREF.

The integrated amplifier 150 amplifies the voltage of the sensing line LSEN and generates the voltage of the charge accumulation line LCA. Preferably, the integrated amplifier 150 has the sensing line LSEN applied to the inverting input terminal (-), the reference voltage VREF applied to the non-inverting input terminal (+), (LCA) is connected.

The multisampling holding unit 200 samples and holds the voltage level of the charge accumulation line LCA at a first sensing timing t1 (see FIG. 4) to generate a first sampling voltage VSAH1, (V2H) by sampling and holding the voltage level of the charge accumulation line (LCA) at the first sampling voltage (t2, see FIG. 4).

The multisample holding unit 200 specifically includes a first sampling holding unit 210 and a second sampling holding unit 220.

The first sampling and holding unit 210 samples and holds the voltage level of the charge accumulation line LCA in response to the first sampling signal XSH1 that is active at the first sensing timing (see t1 in FIG. 4) do. At this time, the voltage level of the charge accumulation line LCA sampled and held is generated as the first sampling voltage VSAH1.

The second sampling and holding unit 220 performs sampling and holding of the voltage level of the charge accumulation line LCA in response to the second sampling signal XSH2 that is active at the second sensing timing (see t2 in FIG. 4) do. At this time, the voltage level of the charge accumulation line LCA sampled and held is generated as the second sampling voltage VSAH2.

The analog-to-digital converter 300 converts the voltage difference between the first sampling voltage VSAH1 and the second sampling voltage VSAH2 into the read data DRDUT of the digital component.

Since the analog-to-digital conversion unit 300 can be easily implemented by those skilled in the art, description thereof will be omitted herein for the sake of simplicity.

The controller 400 provides the driving signal XDR and the compensation signal XCM. At this time, in order to at least partially cancel the effect of the coupling of the sense capacitor CPSA with respect to the sensing line LSEN and the coupling effect of the compensation capacitor CPSA with respect to the sensing line LSEN, The driving signal XDR and the compensation signal XCM are driven in a complementary phase. That is, the driving signal XDR is activated at the first sensing timing (see t1 in FIG. 4) and deactivated at the second sensing timing (see t2 in FIG. 4). Then, the compensation signal XCM is deactivated at the first sensing timing (see t1 in Fig. 4) and is activated at the second sensing timing (see t2 in Fig. 4).

Next, the operation of the touch sensing system of the first embodiment will be described.

4 is a timing chart of a main signal for explaining an example of the operation of the touch sensing system of the first embodiment.

In Fig. 4, it is assumed that a finger contact occurs in the sense capacitor CPSA. In this case, the substantial capacitance of the sense capacitor CPSA becomes smaller than the capacitance of the compensation capacitor CPCM.

The compensating capacitor Cs generated by the application of the compensation signal XCM is greater than the voltage level of the sensing signal XSEN due to the coupling effect of the sensing capacitor CPSA generated by application of the driving signal XDR. A change in the voltage level of the sensing signal XSEN due to the coupling effect of the CPCM becomes large.

Therefore, at the first sensing timing (t1) at which the driving signal (XDR) is activated to "H" and the compensation signal (XCM) is deactivated to "L", the voltage level of the sensing signal (XSEN) Becomes lower than the voltage VREF. As a result, the voltage level of the charge accumulation line ICA becomes higher than the reference voltage VREF.

At this time, at the first sensing timing t1, the first sampling signal XSH1 is in the active state. Therefore, the first sampling voltage VSAH1 generated from the first sampling and holding unit 210 rises. Also, as the first sensing timing t1 is repeated, the first sampling voltage VSAH1 gradually rises.

At the second sensing timing (t2) at which the driving signal (XDR) is deactivated to "L " and the compensation signal (XCM) is activated to" H ", the voltage level of the sensing signal (XSEN) Becomes higher than the voltage VREF. As a result, the voltage level of the charge accumulation line ICA becomes lower than the reference voltage VREF.

At this time, at the second sensing timing t2, the second sampling signal XSH2 is in the active state. Therefore, the second sampling voltage VSAH2 generated from the second sampling and holding unit 220 falls. As a result, as the second sensing timing t2 is repeated, the second sampling voltage VSAH2 gradually drops.

The voltage difference between the first sampling voltage VSAH1 and the second sampling voltage VSAH2 is sensed by the analog-to-digital converter 300 and is generated as the read data DRDUT.

On the other hand, when the finger is not in contact, the substantial capacitance of the sense capacitor CPSA is equal to the capacitance of the compensation capacitor CPCM.

In this case, a change in the voltage level of the sensing signal XSEN due to the coupling effect of the sense capacitor CPSA caused by the application of the driving signal XDR and the application of the compensation signal XCM The changes in the voltage level of the sensing signal XSEN due to the coupling effect of the compensation capacitor CPCM cancel each other out.

Therefore, at the first sensing timing (t1) and the second sensing timing (t2), the voltage level of the sensing signal (XSEN) and the level of the first and second sampling voltages (VSAH1, VSAH2) The voltage VREF is maintained. That is, the voltage difference between the first sampling voltage VSAH1 and the second sampling voltage VSAH2 hardly occurs, and as a result, the read data DRDUT represents the reference data value.

As described above, it is possible to recognize whether or not a finger is touched to the sensing capacitor CPSA and a part of the touched finger through the data value of the read data DRDUT.

In summary, in the touch sensing system of the first embodiment, as the operation progresses, the first sampling voltage VSAH1 gradually increases and the second sampling voltage VSAH2 gradually decreases.

Therefore, the voltage difference between the first sampling voltage VSAH1 and the second sampling voltage VSAH2 in the touch sensing system of the first embodiment is the difference between the first sampling voltage VSH1 and the second sampling voltage VSH2 Compared to a touch sensing system with one fixed and the other one rising or falling, it doubles.

Thus, according to the touch sensing system of the first embodiment, the sensing performance of the finger contact and the degree of contact of the finger is greatly improved.

Meanwhile, the touch sensing system of the present invention can be modified into various forms of implementation.

Second Embodiment

5 is a diagram illustrating a touch sensing system according to a second embodiment of the present invention. 5, the touch sensing system of the second embodiment includes a sense capacitor CPSA, a sensing line LSEN, a compensation capacitor CPCM, a charge integration unit 500, a multisampling integration unit 600, Unit 700 and a control unit 800.

Similarly to the first embodiment, the sensing capacitor CPSA is disposed in a recognition panel CONPAN and includes a sensing line LSEN, a compensation capacitor CPCM, a charge integration unit 100, a multisampling integration unit 600 ), The analog-to-digital converter 700 and the controller 800 may be arranged in the read block BKRD.

Also, a plurality of the sense capacitors CPSA may be arranged in the recognition panel CONPAN. However, in the present specification, for simplicity of description, only one sense capacitor (CPSA) is representatively shown and described. However, this is merely for convenience of explanation, and the technical idea of the present invention is not limited thereto.

The sensing capacitor CPSA includes a driving electrode EDR and a sensing electrode EDT. The driving electrode EDR is coupled to the driving signal XDR. A dielectric may be formed between the driving electrode EDR and the sensing electrode EDT so that the sensing electrode EDT is capacitively coupled to the driving electrode EDR. Accordingly, the induced charge corresponding to the driving signal XDR applied to the driving electrode EDR is stored in the sensing capacitor CPSA.

 Here, the sense capacitor CPSA has a specific capacitance. However, the capacitance of the sense capacitor CPSA is reduced as the finger contacts. A difference in the amount of change of the substantial capacitances of the sense capacitor CPSA occurs depending on the degree of contact of an object such as a finger and whether the finger is in contact with a ridge or a valley.

As a result, the sensing electrode EDT, which is one terminal of the sensing capacitor CPSA, has a voltage level that is differentiated depending on the degree of contact of the finger, the portion thereof, and the like.

The sensing line LSEN is electrically connected to the sensing electrode EDT of the sense capacitor CPSA. Accordingly, the sensing signal XSEN provided to the sensing line LSEN may be a voltage level of the sensing electrode EDT, and ultimately a level corresponding to the amount of charge stored in the sense capacitor CPSA I have.

In other words, the sensing signal XSEN has a voltage level that is differentiated according to the degree of contact of the finger and the portion thereof.

One terminal of the compensation capacitor CPCM is electrically connected to the sensing line LSEN and the other terminal is coupled to the compensation signal XCM.

At this time, the compensation capacitor CPCM has a capacitance corresponding to the inherent capacitance of the sense capacitor CPSA. Preferably, the compensation capacitor CPCM has the same capacitance as the inherent capacitance of the sense capacitor CPSA.

The charge accumulation unit 500 is formed between the sensing line LSEN and the charge accumulation line LCA and generates a voltage level according to the charge received in the sensing line LSEN in the charge accumulation line LCA do. The charge integration unit 500 is driven to reset the sensing line LSEN and the charge integration line LCA in response to activation of the reset signal RST.

According to a preferred embodiment, the charge accumulator 500 includes a charge capacitor 510, a reset switch 530, and an integrated amplifier 550.

The storage capacitor 510 is formed between the sensing line LSEN and the charge accumulation line LCA.

The reset switch 530 is driven to electrically connect the sensing line LSEN and the charge accumulation line LCA in response to the activation of the reset signal RST. At this time, the sensing line LSEN and the charge accumulation line LCA are reset to the reference voltage VREF.

The integrated amplifier 550 amplifies the voltage of the sensing line LSEN and generates the voltage of the charge accumulation line LCA. Preferably, the integrated amplifier 150 has the sensing line LSEN applied to the inverting input terminal (-), the reference voltage VREF applied to the non-inverting input terminal (+), (LCA) is connected.

The multisample integration unit 600 samples the charge of the spare line LPR at the first sensing timing t11 (see FIG. 6) and outputs the first sampling integration voltage VSCA1 to the first sampling integration line LSCA1 And generates the second sampling integration voltage VSCA2 in the second sampling integration line LSCA2 by sampling the charge of the spare line LPR at the second sensing timing t12 (see Fig. 6).

At this time, the spare line (LPR) is coupled to the charge accumulation line (LCA). Preferably, the touch sensing system of the second embodiment further comprises a coupling capacitor (CPCP) coupling the spare line (LPR) to the charge accumulation line (LCA).

The multisample accumulating unit 600 specifically includes a first sampling accumulation unit 610 and a second sampling accumulation unit 620.

The first sampling integration unit 610 samples and accumulates the charges of the spare line LPR in response to the first sampling signal XSH1 that is active at the first sensing timing (see t11 in Fig. 6) . The charge of the spare line LPR sampled at the first sensing timing (see t11 in Fig. 6) is generated as the first sampling integration voltage VSCA1 in the first sampling integration line LSCA1.

The first sampling integration unit 610 then outputs the first transmission line LTR1 and the first sampling integration line LSCA1 to the first integrated reference voltage VRF1 in response to the activation of the integrated reset signal RSTN, .

Preferably, the first sampling integration unit 610 includes a first switch SW1, a first storage capacitor 611, a first integrated reset switch 613, and a first internal integrated amplifier 615.

The first switch SW1 switches the first transmission line LTR1 to the spare line LPR in response to the first sampling signal XSH1 activated at the first sensing timing (see t11 in Fig. 6) Connect.

The first storage capacitor 611 is formed between the first transmission line LTR1 and the first sampling integration line LSCA1.

The first integrated reset switch 613 is driven to electrically connect the first transmission line LTR1 and the first sampling integrated line LSCA1 in response to the activation of the integrated reset signal RSTN. At this time, the first transmission line LTR1 and the first sampling integration line LSCA1 are reset to the first integrated reference voltage VRF1.

The first internal integrated amplifier 615 amplifies the voltage of the first transmission line LTR1 and generates the first sampling integrated voltage VSCA1 in the first sampling integrated line LSCA1. Preferably, the first internal integrated amplifier 615 receives the first transmission line LTR1 at the inverting input terminal - and the first integrated reference voltage VRF1 at the non-inverting input terminal + And an output terminal connected to the first sampling integration line (LSCA1).

The second sampling integration unit 630 samples and accumulates the charges of the spare line LPR in response to the second sampling signal XSH1 that is active at the second sensing timing (see t12 in Fig. 6) . The charge of the spare line LPR sampled at the second sensing timing (see t12 in Fig. 6) is generated as the second sampling integration voltage VSCA2 in the second sampling integration line LSCA2.

The second sampling integration unit 630 then outputs the second transmission line LTR2 and the second sampling integration line LSCA2 to the second integrated reference voltage VRF2 in response to the activation of the integrated reset signal RSTN, .

Preferably, the second sampling integration unit 630 includes a second switch SW2, a second storage capacitor 631, a second integrated reset switch 633, and a second internal integrated amplifier 635. [

In response to the second sampling signal XSH2 being active in the second sensing timing (see t12 in FIG. 6), the second switch SW2 switches the second transmission line LTR2 to the spare line LPR Connect.

The second storage capacitor 631 is formed between the second transmission line LTR1 and the second sampling accumulation line LSCA2.

The second integrated reset switch 633 is driven to electrically connect the second transmission line LTR2 and the second sampling integrated line LSCA2 in response to the activation of the integrated reset signal RSTN. At this time, the second transmission line LTR2 and the second sampling integration line LSCA2 are reset to the second integrated reference voltage VRF2.

The second internal integrated amplifier 635 amplifies the voltage of the second transmission line LTR2 and generates the second sampling integrated voltage VSCA2 in the second sampling integration line LSCA2. Preferably, the second internal integrated amplifier 635 receives the second transmission line LTR2 at the inverting input terminal - and the second integrated reference voltage VRF2 at the non-inverting input terminal + And an output terminal connected to the second sampling integration line (LSCA2).

The analog-to-digital converter 700 converts the voltage difference between the first sampling integrated voltage VSCA1 and the second sampling integrated voltage VSCA2 into the read data DRDUT of the digital component.

The controller 800 provides the driving signal XDR and the compensation signal XCM. At this time, in order to at least partially cancel the effect of the coupling of the sense capacitor CPSA with respect to the sensing line LSEN and the coupling effect of the compensation capacitor CPSA with respect to the sensing line LSEN, The driving signal XDR and the compensation signal XCM are driven in a complementary phase. That is, the driving signal XDR is activated at the first sensing timing (see t11 in FIG. 6) and deactivated at the second sensing timing (see t12 in FIG. 6). Then, the compensation signal XCM is deactivated at the first sensing timing (see t11 in Fig. 6) and activated at the second sensing timing (see t12 in Fig. 6).

Next, the operation of the touch sensing system of the second embodiment will be described.

6 is a timing chart of a main signal for explaining an example of the operation of the touch sensing system of the second embodiment.

In Fig. 6, similarly to Fig. 4, it is assumed that a finger contact occurs in the sense capacitor CPSA. In this case, the substantial capacitance of the sense capacitor CPSA becomes smaller than the capacitance of the compensation capacitor CPCM.

The compensating capacitor Cs generated by the application of the compensation signal XCM is greater than the voltage level of the sensing signal XSEN due to the coupling effect of the sensing capacitor CPSA generated by application of the driving signal XDR. A change in the voltage level of the sensing signal XSEN due to the coupling effect of the CPCM becomes large.

Meanwhile, in the second embodiment, the integrated reset signal RSTN is in an inactive state during the sensing operation. Therefore, the reset state of the first sampling integration unit 610 and the second sampling integration unit 630 is released.

Subsequently, the operation at the first sensing timing t11 and the second sensing timing t12 will be described.

In the first sensing timing t11 at which the driving signal XDR is activated to "H" and the compensation signal XCM is deactivated to "L", the voltage level of the sensing signal XSEN is lower than the reference voltage VREF). As a result, the voltage level of the charge accumulation line ICA becomes higher than the reference voltage VREF. As a result, the voltage level of the spare node (LPR) also rises.

At this time, at the first sensing timing t11, the first sampling signal XSH1 is in the active state. Therefore, the first sampling integrated voltage VSCA1 generated from the first sampling integration unit 610 becomes lower than the first integrated reference voltage VRF1. Also, as the first sensing timing t11 is repeated, the first sampling integrated voltage VSCA1 gradually decreases.

At the second sensing timing (t12) at which the driving signal (XDR) is deactivated to "L" and the compensation signal (XCM) is activated to "H", the voltage level of the sensing signal (XSEN) Becomes higher than the voltage VREF. As a result, the voltage level of the charge accumulation line ICA becomes lower than the reference voltage VREF. Accordingly, the voltage level of the spare node (LPR) is also lowered.

At this time, at the second sensing timing t12, the second sampling signal XSH2 is in an active state. Therefore, the first sampling integrated voltage VSCA1 generated from the second sampling integration unit 630 becomes higher than the second integrated reference voltage VRF2. Also, as the second sensing timing t12 is repeated, the second sampling integrated voltage VSCA2 gradually rises.

The voltage difference between the first sampling integrated voltage VSCA1 and the second sampling integrated voltage VSCA2 is sensed by the analog digital converter 700 and is generated as the read data DRDUT.

Meanwhile, in the touch sensing system of the present invention, the voltage difference of the second sampling integrated voltage VSCA2 with respect to the first sampling integrated voltage VSCA1 may be negative. That is, as shown in FIG. 5, it is assumed that the second integrated reference voltage VRF2 is set lower than the first integrated reference voltage VRF1.

Then, in a period PNG where the contact intensity is lower than the boundary strength MG, a voltage difference of the second sampling integrated voltage VSCA2 with respect to the first sampling integrated voltage VSCA1, that is, The level obtained by subtracting the first sampling integrated voltage VSCA1 from the VSCA2 is a negative value.

That is, the range of the voltage difference of the second sampling integrated voltage VSCA2 with respect to the first sampling integrated voltage VSCA1 provided to the analog-digital converter 700 is extended to the negative (-) region. As a result, according to the touch sensing system of the present invention, the contact strength of the finger can be recognized more precisely.

Of course, in the touch sensing system of the present invention, the first integrated reference voltage VRF1 and the second integrated reference voltage VRF2 may be set at the same level. In this case, since it can be implemented with one reference voltage, a relative advantage arises in the implementation of the touch sensing system of the present invention.

On the other hand, when the finger is not in contact, the substantial capacitance of the sense capacitor CPSA is equal to the capacitance of the compensation capacitor CPCM.

In this case, a change in the voltage level of the sensing signal XSEN due to the coupling effect of the sense capacitor CPSA caused by the application of the driving signal XDR and the application of the compensation signal XCM The changes in the voltage level of the sensing signal XSEN due to the coupling effect of the compensation capacitor CPCM cancel each other out.

Therefore, at the first sensing timing (t11) and the second sensing timing (t12), the voltage level of the sensing signal (XSEN) and the first sampling integration voltage (VSCA1) and the second sampling integration voltage VSCA2 maintain the first integrated reference voltage VRF1 and the second integrated reference voltage VRF2, respectively. That is, the voltage difference between the first sampling integrated voltage VSCA1 and the second sampling integrated voltage VSCA2 hardly changes, and as a result, the read data DRDUT indicates the reference data value.

As described above, it is possible to recognize whether or not a finger is touched to the sensing capacitor CPSA and a portion of the touched finger through the data value of the read data DRDUT.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

Claims (12)

In a touch sensing system,
A sensing capacitor comprising a driving electrode and a sensing electrode, wherein the driving electrode is coupled to a driving signal, the sensing electrode being capacitively coupled to the driving electrode;
A sensing line electrically connected to the sensing electrode of the sensing capacitor;
A compensation capacitor electrically coupled to the sensing line at one terminal and coupled to the compensation signal at the other terminal;
A charge accumulation unit formed between the sensing line and the charge accumulation line, the charge accumulation unit accumulating the charges of the sensing line and driving the charge accumulation line to a level corresponding to the accumulated charge;
Sampling and holding a voltage level of the charge accumulation line at a first sensing timing to generate a first sampling voltage and a voltage level of the charge accumulation line at a second sensing timing to generate a second sampling voltage, part;
An analog-to-digital converter converting the voltage difference between the first sampling voltage and the second sampling voltage into read data of a digital component; And
A control unit for providing the drive signal and the compensation signal to at least partially cancel an effect of coupling the sense capacitor to the sensing line and an effect of coupling the compensation capacitor to the sensing line, Wherein the driving signal is activated at the first sensing timing and deactivated at the second sensing timing and the compensation signal is deactivated at the first sensing timing and activated at the second sensing timing Detection system.
2. The apparatus of claim 1, wherein the compensation capacitor
And a capacitance corresponding to the sensing capacitor.
3. The apparatus of claim 2, wherein the compensation capacitor
Wherein the sensing capacitor has the same capacitance as the sensing capacitor.
The apparatus of claim 1, wherein the multisampling and holding unit
A first sampling and holding unit for sampling and holding the voltage level of the charge accumulation line in response to a first sampling signal activated at the first sensing timing to generate the first sampling voltage; And
And a second sampling and holding unit for sampling and holding a voltage level of the charge accumulation line in response to a second sampling signal activated in the second sensing timing to generate the second sampling voltage as the second sampling voltage. system.
In a touch sensing system,
A sensing capacitor comprising a driving electrode and a sensing electrode, wherein the driving electrode is coupled to a driving signal, the sensing electrode being capacitively coupled to the driving electrode;
A sensing line electrically connected to the sensing electrode of the sensing capacitor;
A compensation capacitor electrically coupled to the sensing line at one terminal and coupled to the compensation signal at the other terminal;
A charge accumulation unit formed between the sensing line and the charge accumulation line, the charge accumulation unit accumulating the charges of the sensing line and driving the charge accumulation line to a level corresponding to the accumulated charge;
The charge of the spare line is accumulated in the first sampling integration line at the first sensing timing and the charge of the spare line is accumulated at the second sensing timing in the first sampling integration line so that the second sampling integration line A multisampling integrated circuit comprising: a multisampling integrated circuit comprising: a multisampling integrated circuit comprising:
An analog-to-digital converter converting the voltage difference between the first sampling integrated voltage and the second sampling integrated voltage into read data of a digital component; And
A control unit for providing the drive signal and the compensation signal to at least partially cancel an effect of coupling the sense capacitor to the sensing line and an effect of coupling the compensation capacitor to the sensing line, Wherein the driving signal is activated at the first sensing timing and deactivated at the second sensing timing and the compensation signal is deactivated at the first sensing timing and activated at the second sensing timing Detection system.
6. The method of claim 5, wherein the compensation capacitor
And a capacitance corresponding to the sensing capacitor.
7. The apparatus of claim 6, wherein the compensation capacitor
Wherein the sensing capacitor has the same capacitance as the sensing capacitor.
6. The apparatus of claim 5, wherein the multisample integration
A first sampling integration unit for sampling the charge of the spare line in response to a first sampling signal activated at the first sensing timing to generate the first sampling integration voltage, The first sampling integration unit resetting one sampling integration line to a first integrated reference voltage; And
A second sampling integration unit for sampling the charge of the spare line in response to a second sampling signal activated at the second sensing timing to generate the second sampling integration voltage, And the second sampling integration unit for resetting the second sampling integration line to a second integrated reference voltage.
9. The method of claim 8,
The first sensing timing is activated by the rising transition and the second sensing timing is caused by the falling transition and is inactivated,
The compensation signal
Wherein the touch sensing device is inactivated by a falling transition at the first sensing timing, and is activated by the rising transition at the second sensing timing.
10. The method of claim 9, wherein the first integrated reference voltage
Wherein the second integrated reference voltage has a level higher than the second integrated reference voltage.
11. The method of claim 10, wherein the first integrated reference voltage and the second integrated reference voltage
The touch sensing system having the same level.
6. The system of claim 5, wherein the touch sensing system
And a coupling capacitor coupling the spare line to the charge integration line.

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