KR20160058273A - Variable-gain amplification circuit, touch input sensing apparatus and touchscreen apparatus - Google Patents

Abstract

The present invention relates to a variable-gain amplification circuit not saturated even when input voltage fluctuates. According to one embodiment of the present invention, the variable-gain amplification circuit comprises: a plurality of capacity array units which include a first capacitor to receive input voltage in a first phase and to receive positive or negative reference voltage in a second phase; and an amplification unit which includes an operation amplifier, a second capacitor to receive the input voltage in the first phase and to receive central reference voltage in the second phase, a third capacitor to receive the input voltage in the first phase and to receive output voltage of the operation amplifier in the second phase, and a fourth capacitor to receive the central reference voltage in the first phase and to receive the output voltage of the operation amplifier in the second phase. Charging voltage of the first to fifth capacitors can be applied to an input terminal of the operation amplifier.

Description

VARIABLE GAIN AMPLIFICATION CIRCUIT, TOUCH INPUT SENSING APPARATUS AND TOUCHSCREEN APPARATUS BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The present invention relates to a variable gain amplifier circuit, a touch sensing device, and a touch screen device.

The capacitance type touch screen includes a plurality of electrodes having a predetermined pattern, and a plurality of nodes, in which a capacitance change is generated by a touch input, are defined by the plurality of electrodes. In a plurality of nodes distributed on a two-dimensional plane, a self-capacitance or a mutual-capacitance is changed by a touch input, and a weighted average The calculation of the touch input can be performed by applying a calculation method or the like.

The variable gain amplifying device for amplifying the level of the capacitance value generated by the touch screen is insufficient for the touch screen device. However, there is a problem that the input voltage to be amplified in the variable gain amplifying device is limited within a range that does not deviate from the dynamic range of the analog digital converter (ADC) and prevents saturation of the variable gain amplifying device.

Korean Patent Publication No. 10-2009-0035358

SUMMARY OF THE INVENTION It is an object of the present invention to provide a variable gain amplifier circuit that does not saturate even when the input voltage fluctuates, and a touch sensing device and a touch screen device including the same.

The variable gain amplifier circuit according to an embodiment of the present invention includes a plurality of capacitor arrays each including a first capacitor to which an input voltage is applied in a first phase and a positive reference voltage or a negative reference voltage is applied in a second phase, part; And a second capacitor to which an input voltage is applied in the first phase and a center reference voltage is applied in the second phase, an input voltage is applied in the first phase, and an input voltage is applied to the operational amplifier in the second phase. A third capacitor to which an output voltage is applied, and a fourth capacitor to which the center reference voltage is applied in the first phase and the output voltage of the operational amplifier is applied in the second phase; An amplification unit including the amplification unit; And a charging voltage of the first to fifth capacitors may be applied to an input terminal of the operational amplifier.

Even when the input voltage varies according to the embodiment of the present invention, the malfunction caused by the saturation of the variable gain amplifier circuit can be prevented and the touch input can be detected stably.

1 is a perspective view illustrating an appearance of an electronic device having a touch screen device according to an embodiment of the present invention.
2 is a view illustrating a panel unit that may be included in a touch screen device according to an exemplary embodiment of the present invention.
3 is a cross-sectional view of a panel portion that may be included in a touch screen device according to an embodiment of the present invention.
4 is a diagram illustrating a touch screen device according to an exemplary embodiment of the present invention.
5 is a diagram illustrating a variable gain amplifier according to an embodiment of the present invention.
6 is a view illustrating a capacitor array unit employed in a variable gain amplifier according to an embodiment of the present invention.
7 is a graph illustrating a clock signal according to an embodiment of the present invention.

The following detailed description of the invention refers to the accompanying drawings, which illustrate, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It should be understood that the various embodiments of the present invention are different, but need not be mutually exclusive. For example, certain features, structures, and characteristics described herein may be implemented in other embodiments without departing from the spirit and scope of the invention in connection with an embodiment. It is also to be understood that the position or arrangement of the individual components within each disclosed embodiment may be varied without departing from the spirit and scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is to be limited only by the appended claims, along with the full scope of equivalents to which such claims are entitled, if properly explained. In the drawings, like reference numerals refer to the same or similar functions throughout the several views.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

1 is a perspective view illustrating an appearance of an electronic device having a touch screen device according to an embodiment of the present invention.

1, an electronic device 100 according to the present embodiment includes a display device 110 for outputting a screen, an input unit 120, an audio unit 130 for outputting audio, And a touch screen device (not shown) formed integrally with the display device 110.

The touch screen device according to an embodiment of the present invention may include a substrate and a panel portion having a plurality of electrodes provided on the substrate. A capacitive sensing circuit for detecting a change in electrostatic capacitance generated at a plurality of electrodes; an analog-to-digital conversion circuit for converting an output signal of the electrostatic capacitance sensing circuit into a digital value; And a controller integrated circuit (contact sensing device) including an arithmetic circuit and the like for judging an input. This will be described in detail with reference to FIG. 2 to FIG.

2 is a view illustrating a panel unit that may be included in a touch screen device according to an exemplary embodiment of the present invention.

Referring to FIG. 2, the panel unit 200 may include a substrate 210 and a plurality of electrodes 220 and 230 provided on the substrate 210. Although not shown in FIG. 2, each of the plurality of electrodes 220 and 230 may be electrically connected to a wiring pattern of a circuit board attached to one end of the substrate 210 through wiring and a bonding pad. A controller integrated circuit is mounted on the circuit board to detect a sensing signal from a plurality of electrodes 220 and 230 and determine a touch input therefrom.

The substrate 210 may be a film such as polyethylene terephthalate (PET), polycarbonate (PC), polyethersulfone (PES), polyimide (PI), polymethlymethacrylate (PMMA) or cycloolefin polymers (COP), soda glass, And may be formed of a material such as tempered glass to have high light transmittance.

A plurality of electrodes 220 and 230 may be provided on one side or both sides of the substrate 210. A plurality of electrodes 220 and 230 having rhombic or diamond patterns are shown in FIG. , Triangle, and the like. The plurality of electrodes 220 and 230 may be formed of an electrically conductive material such as indium-tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), carbon nanotube (CNT), or graphene (Al), chrome (Cr), nickel (Ni), molybdenum (Mo), and copper (Cu), or an alloy thereof. And a conductor line. At this time, the conductor line may be formed in a mesh shape.

The plurality of electrodes 220 and 230 may include a first electrode 220 extending in the X axis direction and a second electrode 230 extending in the Y axis direction. The first electrode 220 and the second electrode 230 may be provided on both sides of the substrate 210 or alternatively may be provided on different substrates 210. If the first electrode 220 and the second electrode 230 are provided on one surface of the substrate 210, A predetermined insulating layer may be partially formed at the intersection of the first electrode 220 and the second electrode 230.

In addition to the area where the plurality of electrodes 220 and 230 are formed, the area where the wiring connected to the plurality of electrodes 220 and 230 is provided is not limited to the predetermined area for visually shielding the wiring formed of the opaque metal material. (Not shown) may be formed on the substrate 210.

A contact sensing device (not shown), which is electrically connected to the plurality of electrodes 220 and 230, provides a driving signal to the first electrode 220 through a channel defined by D1 to D8, In this case, the touch sensing device can determine the touch input according to a change in capacitance generated at the intersection of the first electrode 220 and the second electrode 230.

3 is a cross-sectional view of a panel portion that may be included in a touch screen device according to an embodiment of the present invention. FIG. 3 is a cross-sectional view of the panel unit 200 shown in FIG. 2 cut in the YZ plane. In FIG. 3, the cover 210 includes a plurality of sensing electrodes 220 and 230, Cover Lens). The cover lens 240 may be provided on the second electrode 230 used for detecting capacitance.

When a driving signal is applied to the first electrode 320 through the channels D1 to D8, a capacitance may be generated between the first electrode 220 and the second electrode 230 to which the driving signal is applied.

When the contact material 250 contacts the cover lens 240, capacitance changes occur at the intersection node of the first electrode 220 and the second electrode 230 corresponding to the contact region. The change in the capacitance may be proportional to the area of the contact object 250. In FIG. 3, the capacitance generated between the first electrode 220 and the second electrode 230 connected to the channels D2 and D3, respectively, Can be influenced by the object (250).

4 is a diagram illustrating a touch screen device according to an exemplary embodiment of the present invention. Referring to FIG. 4, the touch screen apparatus according to the present embodiment may include a panel unit 200 and a touch sensing apparatus 300.

As described above, the panel unit 200 includes a substrate (not shown) and a first axis-a first electrode 220 in a plurality of rows extending in the transverse direction of FIG. 4, and a second electrode And may include a plurality of rows of second electrodes 230 extending in the longitudinal direction of the axis-FIG. Capacitance may be generated at the intersection of the plurality of first electrodes 220 and the plurality of second electrodes 230. The node capacitors C11 to Cmn shown in FIG. 4 may include a plurality of first electrodes 220 and second And the capacitances generated at the intersections of the electrodes 230 are shown as the capacitor components.

The touch sensing apparatus 300 may include a driving circuit unit 310, a sensing circuit unit 320, a variable gain amplifying unit 340, a signal converting unit 350, and a calculating unit 360, 330). At this time, the driving circuit unit 310, the sensing circuit unit 320, the signal transmission unit 330, the variable gain amplification unit 340, the signal conversion unit 350 and the calculation unit 360 are integrated into one integrated circuit (IC) Can be implemented.

The driving circuit unit 310 includes at least one driving signal generating circuit 315 and applies a predetermined driving signal to the plurality of first electrodes 210 of the panel unit 310. The driving signal may be a square wave, a sine wave, a triangle wave, or the like having a predetermined period and amplitude. Although the driving signal generating circuit 315 is shown separately connected to each of the plurality of first electrodes 220 in FIG. 4, the driving signal generating circuit 315 may include one driving signal generating circuit 315, It is also possible to apply a driving signal to each of the electrodes 220.

The driving circuit unit 310 may sequentially apply a driving signal to each of the plurality of first electrodes 220. In addition, it is possible to operate in a method of simply sensing the presence or absence of a touch input by simultaneously applying a driving signal to a plurality of first electrodes 220 or selectively applying a driving signal selectively to only a part of the plurality of first electrodes 220 have.

The sensing circuit unit 320 detects the capacitances of the node capacitors C11-Cmn from the plurality of second electrodes 230. [ The sensing circuit portion 320 may include a plurality of CV conversion circuits 325 each having at least one operational amplifier and at least one capacitor, and each of the plurality of CV conversion circuits 325 includes a plurality of second electrodes 230, respectively.

The plurality of CV conversion circuits 325 can output analog signals by changing the electrostatic capacitances of the node capacitors C11 to Cmn to voltage signals. For example, the plurality of CV conversion circuits 325 integrate the electrostatic capacitance to generate a predetermined voltage And output it.

Since the capacitance can be simultaneously detected from the plurality of second electrodes 230 when the drive signal is sequentially applied to the plurality of first electrodes 220, the CV conversion circuit 325 converts the plurality of second electrodes 230 As shown in FIG.

The signal transfer unit 330 receives a plurality of analog signals output from the plurality of CV conversion circuits 325 of the sensing circuit unit 320 and may sequentially or sequentially transmit the analog signals to the variable gain amplification unit 340 . The signal transmission unit 330 may include a multiplexer for selecting one of a plurality of input signals and outputting the same as one output line.

The variable gain amplifying unit 340 may variably amplify the analog signal transmitted from the signal transmitting unit 330 and provide the amplified analog signal to the signal converting unit 350. The configuration and operation of the variable gain amplifier 340 will be described later.

The signal converting unit 350 generates the digital signal S _D from the analog signal output from the sensing circuit unit 320. For example, the signal converter 350 may include a time-to-analog converter (TDC) that converts the analog signal output from the sensing circuit 320 to a predetermined reference voltage level and converts the analog signal to a digital signal S _D , Digital Converter) circuit or an ADC (Analog-to-Digital Converter) circuit for measuring the amount of change of the level of the analog signal output from the sensing circuit unit 320 for a predetermined time and converting it into a digital signal S _D .

The operation unit 360 determines the touch input applied to the panel unit 200 using the digital signal S _D. The number of touch inputs applied to the panel unit 200, coordinates, and gesture operation can be determined using the digital signal S _D.

The digital signal S _D as a basis for determining the touch input by the operation unit 360 may be data obtained by digitizing a change in the capacitance of the node capacitors C11 to Cmn. In particular, when the touch input is not generated, And may be data indicating a difference in capacitance when the capacitance is generated. Generally, in a capacitive touch screen device, a region where a conductive object is in contact decreases in capacitance as compared with a region where no contact occurs, so that a change in capacitance of a region in which a conductive object is in contact is smaller It appears large.

5 is a diagram illustrating a variable gain amplifier (variable gain amplifier circuit) 340 according to an embodiment of the present invention. 6 is a diagram illustrating a capacitor array unit 340a employed in the variable gain amplifier 340 according to an embodiment of the present invention. Hereinafter, the configuration and operation of the variable gain amplifier 340 according to an embodiment of the present invention will be described in detail with reference to FIG. 5 and FIG.

Referring to FIGS. 5 and 6, the variable gain amplifier 340 may include a capacitor array unit 340a and a sampling / amplification module 340b. Although one capacitor array unit 340a is shown as being connected to the operational amplifier OPA in FIG. 5, it is schematically shown, and a plurality of capacitor array units 340a may be connected to the operational amplifier OPA.

The capacitor array portion 340a may include a plurality of switches SW1 - SW5 and at least one capacitor C1, and the sampling / amplification module 340b may include a plurality of switches SW6 - SW12, a plurality of capacitors C2 - C4 and at least one And may include an operational amplifier OPA.

In FIGS. 5 and 6, the input voltages Vinp and Vinn may be voltages corresponding to a plurality of analog signals generated by the plurality of CV conversion circuits 325 of the sensing circuit unit 320. The plurality of CV conversion circuits 325 can invert not only the input voltage Vinp corresponding to the positive voltage but also the input voltage Vinp to generate the input voltage Vinn corresponding to the negative voltage.

5 and 6, the configuration of the capacitor array part 340a and the sampling / amplification module 340b are shown connected to the non-inverting input terminal and the inverting input terminal of the operational amplifier OPA, respectively. However, the non-inverting input terminal And the configuration of the capacitor array part 340a and the sampling / amplification module 340b may be connected only to the input side of one of the inverting input terminals.

The configuration and operation of the capacitor array portion 340a and the sampling / amplification module 340b disposed at the non-inverting input end side of the operational amplifier OPA are the same as those of the capacitor array portion 340a and the sampling / Amplification module 340b and the capacitor array unit 340a disposed on the inverting input terminal side will be described below with reference to the constitution and operation of the sampling / amplification module 340a and the sampling / amplification module 340b .

The capacitor array unit 340a may include a plurality of switches SW1 to SW5 and at least one capacitor C1. More specifically, the switches SW1 and SW2, the capacitor C1 and the switch SW3 may be serially connected in series, the voltage Vinp may be applied to the switch SW1 side, and the switch SW3 may be connected to the inverting input terminal of the operational amplifier OPA. The other end of the switch SW4 having one end to which the reference voltage Vrefp-positive reference voltage- is applied can be connected to the connection node between the switch SW2 and the capacitor C1, and has one end to which the reference voltage Vrefn- The other end of the switch SW5 may be connected to the connection node of the switch SW2 and the capacitor C1.

The sampling / amplification module 340b may include a plurality of switches SW6-SW12, a plurality of capacitors C2-C4, and at least one operational amplifier OPA. Specifically, the switch SW6 and the capacitor C2 that are connected in series to each other can be disposed between the input terminal of the voltage Vinp and the inverting input terminal of the operational amplifier OPA. Further, the switch SW8 and the capacitor C3 which are connected in series to each other can be disposed between the input terminal of the voltage Vinp and the inverting input terminal of the operational amplifier OPA.

The other end of the switch SW7 having one end to which the reference voltage Vref - the center reference voltage - is applied may be connected to the connection node of the switch SW6 and the capacitor C2. The switch SW8 and the capacitor C4 which are connected in series to each other can be disposed between the input terminal of the reference voltage Vref and the inverting input terminal of the operational amplifier. The switch SW10 may be disposed between the connection node of the capacitors C2 and C3 and the non-inverting output terminal of the operational amplifier OPA, and the switch SW11 may be disposed between the connection node of the switch SW8 and the capacitor C3 and the noninverting output terminal of the operational amplifier OPA , The switch SW12 may be disposed between the connection node of the switch SW1 and the capacitor C4 and the non-inverting output terminal of the operational amplifier OPA.

The plurality of switches SW1 to SW12 can be switched by the control signals gain_ctl, clt, clt_b and the clock signals ph1 and ph2. When the control signals gain_ctl, clt, clt_b and the clock signals ph1 and ph2 are at the high level, the switch can be turned on and can be turned off at the low level.

When the control signal gain_ctl is high level, the switches SW1 and SW3 are turned on, the capacitor C1 can be connected to the inverting input terminal of the operational amplifier, and when the control signal gain_ctl is low, the switches SW1 and SW3 are turned off, The inverting input of the operational amplifier may not be connected.

As described above, the plurality of capacitor array units 340a may be connected to the variable gain amplifier 340, and the number of the capacitors C1 connected to the operational amplifier OPA may be determined according to the control signal gain_ctl. In other words, the plurality of capacitor array units 340a can be disconnected from the operational amplifier circuitally in accordance with the control signal gain_ctl.

The control signal gain_ctl can determine the number of capacitors C1 connected to the OPA according to the variation range of the voltage Vinp, which will be described later with reference to Tables 1 to 4 below.

7 is a graph illustrating clock signals ph1 and ph2 according to an embodiment of the present invention. The plurality of switches SW4 to SW12 can be operated by the clock signals ph1 and ph2 as shown in Figs.

The clock signals ph1 and ph2 may correspond to clock signals having different on timings, i.e., non-overlapping on timings. The clock signal ph1 may have a high level in the first phase and the clock signal ph2 may have a high level in the second phase.

Even when the control signal gain_ctl is at a high level, since the voltage Vinp can not be charged to the capacitor C1 when the clock signal ph1 is at the low level, it can be seen that the voltage Vinp is applied to the capacitor C1 according to the first phase.

The control signals ctl and ctl_b may correspond to signals inverted from each other. The control signals ctl and ctl_b control the switches sw4 and sw5, and the switches sw4 and sw5 are switched according to the control signals ctl and ctl_b to charge the capacitor C1 with the voltages Vrefn and Vrefp.

The control signals ctl and ctl_b can be synchronized with the clock signal ph2 and applied to the switches sw4 and sw5. Specifically, the control signals ctl and ctl_b can be applied to the switches sw4 and sw5 in the second phase, which is the high level interval of the second clock signal. That is, it can be seen that the clock signal ph2 is applied to one of the switches sw4 and sw5 included in one capacitor array unit 340a, and the other switch is off.

One of the switches sw4 and sw5 provided in one capacitor array unit 340a is turned on and the other switch is turned off. At this time, some of the capacitor array units 340a of the plurality of capacitor array units 340a can turn on the switch sw4, and the remaining capacitor array units 340a can turn on the switch sw5.

The number of ctl and ctl_b set to the high or low level can be determined according to the variation range of the voltage Vinp, which will be described later with reference to Tables 1 to 4 below.

When the control signal gain_ctl is at the high level and the clock signal ph1 is at the high level, the charges Qc1 to Qc4 charged in the capacitors C1 to C4 in accordance with the charge conservation law are expressed by Equation 1 below. Since the clock signal ph1 is at the high level, the switches sw4 and sw5 capable of switching operation in the second phase, which is the high level section of the clock signal ph2, can be turned off.

Assuming that the control signal gain_ctl is at the high level and the clock signal ph2 is at the high level and that the switch sw4 of the switches sw4 and sw5 is on in the second phase which is the high level section of the clock signal ph2, The charge Qc1 - Qc4 charged in the capacitors C1 - C4 according to the law is expressed by Equation 2 below.

At this time, if the left side and the right side of Equations (1) and (2) are added together, the following Equation (3) can be calculated.

When the level of the voltage Vref in Equation (3) is 0, Equation (3) can be changed to Equation (4).

Assuming that fourteen capacitor array units 340a are provided and the capacitances of the capacitors C1, C2, C3, and C4 are all the same, Equation (4) can be changed to Equation (5).

It is assumed that the control signal ctl is at the high level in the N capacitor array units 340a and the control signal ctl is set to the high level in the (14-N) capacitor array units 340a when the capacitor array unit 340a is provided with fourteen When the signal ctl_b is at a high level, Equation (5) can be changed as shown in Equation (6) below. Here, N_ctl represents the number of control signals ctl controlled to a high level.

In generalizing Equation (6) as shown in Equation (4), Equation (6) can be changed to Equation (7).

Equation (8) below expresses the relationship between the voltage Vinp and the voltage Voutp according to the number of the capacitor array units 340a connected to the operational amplifier OPA in the control signal gain_ctl. In the following Equation 8, when the capacitor array unit 340a is not connected to the operational amplifier OPA, that is, when none is connected, the voltage Voutp is equal to Vinp, and the capacitor array unit 340a is connected to the operational amplifier OPA The voltage Voutp corresponds to twice Vinp and the voltage Voutp corresponds to four times Vinp when the capacitor array unit 340a is connected to the operational amplifier OPA and the capacitor array unit 340a is connected to the operational amplifier OPA. When 14 connections are made with the OPA, the voltage Voutp corresponds to 8 times the Vinp. Here, it is assumed that the capacitances of the capacitors C1, C2, C3, and C4 are all the same.

The control signals gain_ctl, ctl, and ctl_b according to an exemplary embodiment of the present invention may be set according to the input range of the voltage Vinp input to the variable gain amplifier 340.

Tables 1, 2 and 3 below show the number N_gain_ctl of the control signals gain_ctl determined to be high level in accordance with the input range of the input voltage Vinp and the number N_gain_ctl of the capacitor arrays connected to the operational amplifier OPA by the high level control signal gain_ctl. Represents the number N_ctl of ctl determined to be a high level applied to the unit 340a.

For example, when the voltage Vinp input to the variable gain amplifier 340 at the time of non-touch is 2.7 V and the voltage Vinp input to the variable gain amplifier 340 at the time of touch is 2.5 V, the input range of the input voltage Vinp is 2.5 to 2.7 V and the delta range is 0.2 V. In this case, the input range of the input voltage Vinp and the interval to which the delta range belongs correspond to a section where N_ctl is 0 in Table 4. [

When N_gain_ctl is set to 14 and N_ctl is set to 0, 2.7 V at non-touch may have an ADC output (ADC out) corresponding to 2925 and 2.5 V at touch may be 585 And the ADC output (ADC out) corresponding to the ADC output. At this time, the difference between the digital level at the time of contact and the non-contact state is 2340, so that a very high SNR can be obtained without saturating the variable gain amplifier 340.

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 exemplary embodiments, but, on the contrary, Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Therefore, the spirit of the present invention should not be construed as being limited to the above-described embodiments, and all of the equivalents or equivalents of the claims, as well as the following claims, I will say.

310:
320:
330:
340: Variable gain amplifier section
340a: Capacitor array part
340b:
350:
360:

Claims (17)

A plurality of capacitor array units each including a first capacitor to which an input voltage is applied in a first phase and a positive reference voltage or a negative reference voltage is applied in a second phase; And
A second capacitor to which an input voltage is applied in the first phase and a center reference voltage is applied in the second phase, an input voltage is applied in the first phase, and an output of the operational amplifier A fourth capacitor to which a center reference voltage is applied in the first phase and an output voltage of the operational amplifier in the second phase is applied; An amplification unit including the amplification unit; Lt; / RTI >
And a charge voltage of the first to fourth capacitors is applied to an input terminal of the operational amplifier.
The variable gain amplifier circuit according to claim 1, wherein some capacitor array portions of the plurality of capacitor array portions are circuit-disconnected from the operational amplifier in accordance with a variation range of the input voltage.
The method according to claim 1,
Wherein some capacitor array portions of the plurality of capacitor array portions are applied with the positive reference voltage to the first capacitor in the second phase and the remaining capacitor array portion receives the positive reference voltage to the first capacitor in the second phase A variable gain amplifier circuit.
The method of claim 3,
Wherein the number of the capacitor array part and the remaining capacitor array part is determined according to the variation range of the input voltage.
The method according to claim 1,
Wherein the center reference voltage is a ground voltage.
The method according to claim 1,
Wherein the first phase and the second phase do not overlap with each other.
A first switch, a second switch, a first capacitor, and a third switch sequentially arranged in series from an input voltage terminal; A fourth switch disposed between the positive reference voltage terminal and the connection node of the second switch and the first capacitor; And a fifth switch disposed between the negative reference voltage terminal and the connection node of the second switch and the first capacitor; A plurality of capacitor array units each having a capacitor; And
Operational amplifiers; A sixth switch and a second capacitor connected in series to each other between the input voltage terminal and the input terminal of the operational amplifier; A seventh switch disposed between a center reference voltage terminal and a connection node of said sixth switch and said second capacitor; An eighth switch and a third capacitor connected in series between the input voltage terminal and the input terminal of the operational amplifier; A ninth switch and a fourth capacitor connected in series to each other and arranged between a center reference voltage terminal and an input terminal of the operational amplifier; A tenth switch disposed between an input terminal and an output terminal of the operational amplifier; An eleventh switch disposed between a connection node of said eighth switch and said third capacitor and an output terminal of said operational amplifier; And a twelfth switch disposed between a connection node of said ninth switch and said fourth capacitor and an output terminal of said operational amplifier; An amplification unit including the amplification unit; And a variable gain amplifier circuit.
8. The method of claim 7,
A control signal is applied to the first switch and the third switch,
Wherein a control signal applied to some capacitor array units of the plurality of capacitor array units is at a high level and a control signal applied to the remaining capacitor array units is at a low level.
9. The method of claim 8,
Wherein the number of the capacitor array part and the remaining capacitor array part is determined according to the variation range of the input voltage.
8. The method of claim 7,
A first clock signal having a first phase is applied to the second switch, the sixth switch, the eighth switch, the ninth switch, and the tenth switch,
And a first clock signal having a second phase is applied to the seventh switch, the eleventh switch, and the twelfth switch.
11. The method of claim 10,
Wherein the first phase and the second phase do not overlap with each other.
11. The method of claim 10,
And a second clock signal is applied to one of the fourth switch and the fifth switch of one of the capacitor array portions of the plurality of capacitor array portions.
13. The method of claim 12,
Wherein a second clock signal is applied to the fourth switch of some of the plurality of capacitor array portions and a second clock signal is applied to the fifth switch of the remaining capacitor array portion.
14. The method of claim 13,
Wherein the number of the capacitor array part and the remaining capacitor array part is determined according to the variation range of the input voltage.
A sensing circuit unit for sensing a change in capacitance caused in the touch panel;

A plurality of capacitor arrays and operational amplifiers each including a first capacitor to which an input voltage according to the capacitance change is applied in a first phase and a first reference voltage to which a positive reference voltage or a negative reference voltage is applied in a second phase, A second capacitor to which an input voltage is applied in one phase and a center reference voltage is applied in the second phase, an input voltage is applied in the first phase, and an output voltage to which the output voltage of the operational amplifier is applied in the second phase And a fourth capacitor to which the center reference voltage is applied in the first phase and the output voltage of the operational amplifier in the second phase is applied, A variable gain amplifier to which a charge voltage of the first to fifth capacitors is applied;
A signal converter for digitally converting an output voltage of the variable gain amplifier; And
An operation unit for determining a touch input according to a digital signal output from the signal conversion unit; And a contact sensing device.
16. The method of claim 15,
A driving circuit for applying a driving signal to a plurality of electrodes of the touch panel; Further comprising:
A panel portion having a plurality of first electrodes extending in a first direction and a plurality of second electrodes extending in a second direction intersecting the plurality of first directions;
A driving circuit for applying a predetermined driving signal to the plurality of first electrodes;
A sensing circuit unit for sensing a change in capacitance from the plurality of second electrodes;
A plurality of capacitor arrays and operational amplifiers each including a first capacitor to which an input voltage according to the capacitance change is applied in a first phase and a first reference voltage to which a positive reference voltage or a negative reference voltage is applied in a second phase, A second capacitor to which an input voltage is applied in one phase and a center reference voltage is applied in the second phase, an input voltage is applied in the first phase, and an output voltage to which the output voltage of the operational amplifier is applied in the second phase And a fourth capacitor to which the center reference voltage is applied in the first phase and the output voltage of the operational amplifier in the second phase is applied, A variable gain amplifier to which a charge voltage of the first to fifth capacitors is applied;
A signal converter for digitally converting an output voltage of the variable gain amplifier; And
An operation unit for determining a touch input according to a digital signal output from the signal conversion unit; The touch screen device comprising:

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