KR20130060069A - Apparatus for sensing charge of multi touch panel - Google Patents

Abstract

PURPOSE: A device for sensing charge amount of a multi-touch panel is provided to accumulate the charge amount without amplification corresponding to a multi-touch state of the multi-touch panel and to reduce noise by a noise standardization role, thereby minimizing the noise. CONSTITUTION: A signal transmitting unit(110) outputs a sensing signal in response to an input selection signal. A capacitance sensor(120) outputs charge amount corresponding to a touch state of a multi-touch panel in response to the sensing signal. A signal receiving unit(130) accumulates the charge amount and removes noise by controlling gains. A multiplexer(145) successively selects and outputs voltages which are outputted from the signal receiving unit in response to a voltage selection signal. An ADC(Analog to Digital Converter)(140) converts the voltages into a digital signal. [Reference numerals] (110) Signal transmitting unit; (131_1,131_k) Sampling unit; (133_1,133_k) Charge accumulation unit; (135) Gain control unit

Description

Apparatus for sensing charge of multi touch panel}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charge amount sensing device of a multi-touch panel. In particular, the amount of charge of a multi-touch panel that maximizes the dynamic range of the system while minimizing noise and ensuring sufficient sensitivity even with small changes in charge amount is reduced. It relates to a device for detecting the.

In general, a touch panel (for example, a touch key, a touch screen, etc.) detects whether a conductor (for example, a finger, a pen, etc.) is touched and outputs a digital signal to detect the amount of charge of the touch panel for use in an application. Use a device to

In order to sense the amount of charge in the touch panel, the method of sensing the amount of charge in the capacitance sensor on the touch panel side is to detect a change in the amount of charge generated by the influence of a conductor that touches, and is currently used in capacitance sensors used in various applications including portable devices. The amount of charge change is not large. The change in the charge amount is proportional to the change in the capacitance value of the capacitance sensor, and the change generally has a capacitance value of several tens fF to several hundred fF.

To amplify the signal sensed by the capacitance sensor in order to increase the change in the amount of charge due to the touch of the conductor, it is generally used, but this method is contrary to the current development trend of low voltage and low power, and is caused by the use of additional external devices. It causes problems in cost increase and battery use applications. In addition, amplification of a simple signal also amplifies the noise at the same rate, resulting in a problem that the noise increases.

The problem to be solved by the present invention is to reduce the noise in the multi-touch panel and the conductor to perform the multi-touch to minimize the noise and ensure sufficient sensitivity even in the small charge change, while ensuring the maximum dynamic range of the system (maximum) An object of the present invention is to provide a charge sensing device of a multi-touch panel.

According to an aspect of the present invention, there is provided an apparatus for detecting a charge amount of a multi-touch panel, the sensing signal including information on a sampling time point to a corresponding input terminal among input terminals of a capacitance sensor in response to an input selection signal. An output signal transmission unit, receiving the sensing signal through the corresponding input terminal, and in response to the received sensing signal, the capacitance sensor for outputting the amount of charges according to the touch state of the multi-touch panel in parallel through a plurality of output terminals; Sampling the charge amounts output in parallel from the capacitance sensor n times (n is a natural number) and accumulating the gains and adjusting the gains to remove noise and output voltages corresponding to the gains in which the gains are adjusted in parallel. A signal receiver and a voltage output from the signal receiver in response to a voltage selection signal And an AD (analog to digital) converter for converting the voltage sequentially output from the mux and sequentially outputting the digital signal to the digital signal.

The signal receiver responds to a first sampling control signal and a second sampling control signal including information on a gain control unit for generating and outputting a plurality of gain control signals using the digital signal output from the AD converter. A plurality of sampling units for sampling the charge amount output from the corresponding output terminal among the output terminals of the capacitance sensor n times and the amount of charges sampled n times by the corresponding sampling unit among the sampling units in response to the gain control signals. And a plurality of charge accumulators for outputting a voltage corresponding to the accumulated charge amount by adjusting gain.

Each of the sampling units may include a first sampling switching unit for connecting or disconnecting a corresponding output terminal of the capacitance sensor and a ground voltage source in response to the first sampling control signal, and a corresponding response of the capacitance sensor in response to the second sampling control signal. And a second sampling switching unit configured to sample and output the amount of charge output from the output terminal, wherein the first sampling switching unit and the second sampling switching unit may be selectively operated.

Each of the charge accumulation units includes an input terminal connected to an output terminal of the corresponding sampling unit, a ground voltage input terminal connected to a ground voltage source, and an output terminal outputting a voltage corresponding to the accumulated charge amount to the mux, the multi-touch panel In case the touch state of is changed or when the charge amount is sampled and accumulated in the corresponding sampling unit n times, the initialization to connect the input terminal and the output terminal of the operational amplifier to initialize the voltage corresponding to the accumulated charge amount in response to an initialization signal. A switching unit, a plurality of capacitors connected in parallel between an input terminal and an output terminal of the operational amplifier, and each of the capacitors connected between an input terminal and an output terminal of the operational amplifier in response to a corresponding gain control signal among the gain control signals Or a plurality of gain control switching unit to cut off A may be provided.

The gain controller decreases the number of capacitors connected between an input terminal and an output terminal of the operational amplifier when the voltage corresponding to the cumulative charge amount is increased, and decreases the voltage corresponding to the accumulated electric charge amount by the operational amplifier. The gain control signals may be generated to increase the number of the capacitors connected between an input terminal and an output terminal of the capacitor.

The signal transfer unit may include a sensing controller configured to generate and output a sensing control signal in response to the digital signal output from the AD converter, and is enabled in response to the input selection signal, and at least one driving signal in response to the sensing control signal. A plurality of sensing drivers for generating and outputting a plurality and a plurality of sensing signal output units for generating the sensing signal in response to the at least one driving signal to output to the corresponding input terminal of the input terminal of the capacitor.

According to an aspect of the present invention, there is provided an apparatus for detecting a charge amount of a multi-touch panel, the sensing signal including information on a sampling time point to a corresponding input terminal among input terminals of a capacitance sensor in response to an input selection signal. An output signal transmission unit, receiving the sensing signal through the corresponding input terminal, and in response to the received sensing signal, the capacitance sensor for outputting the amount of charges according to the touch state of the multi-touch panel in parallel through a plurality of output terminals; And generating a plurality of offset control signal groups for setting offset charge amounts corresponding to each charge amount by using the charge amounts output from each of the output terminals of the capacitance sensor during the offset charge amount setting period, and responding to the offset control signal groups. Parallel in the capacitance sensor An automatic correction unit which generates correction charges in which the corresponding offset charges are removed from the offset charges and outputs them in parallel, and accumulates the corrected charges by sampling n times (n is a natural number). A signal receiver which removes noise by adjusting gain and outputs voltages corresponding to accumulated charge amounts in parallel, and sequentially selects voltages output from the signal receiver in response to a voltage selection signal. A mux for outputting and an AD (analog to digital) converter for converting the voltage sequentially output from the mux to a digital signal and sequentially output.

The signal receiver may accumulate and accumulate the charges output in parallel from the capacitance sensor n times during the offset charge setting period, and adjust the gain to remove voltages corresponding to the accumulated charges of which noise is removed and gain is adjusted. And the mux sequentially selects and outputs voltages output from the signal receiver one by one in response to the voltage selection signal during the offset charge amount setting period, and the AD converter is output from the mux during the offset charge amount setting period. Converts the voltage into a digital signal and outputs the digital signal, and the auto-correction unit uses the digital signal output from the AD converter during the offset charge amount setting period and the offset control signal group corresponding to each charge amount output from the capacitance sensor To produce The corrected charge amount is obtained by removing the corresponding offset charge amount among the offset charge amounts from the corresponding charge amount among the charge amounts output from the capacitance sensor in response to a corresponding offset control signal group among the offset control signal generator and the offset control signal groups. It may be provided with a plurality of offset compensation unit to generate and output.

Each of the offset compensators may include a plurality of correction capacitors having one end connected between a corresponding output terminal among the output terminals of the capacitance sensor and a corresponding input terminal among the input terminals of the signal receiver, and a corresponding offset among the corresponding offset control signal groups. In response to the control signal, a plurality of offset compensation switching units for connecting one voltage source of the first voltage source and the second voltage source and the other end of the corresponding correction capacitor among the correction capacitors may be provided.

An apparatus for detecting a charge amount of a multi-touch panel according to an exemplary embodiment of the present invention minimizes noise by attenuating noise by acting as averaging noise by accumulating without amplifying charge amounts according to a multi-touch state of a multi-touch panel. Compared to the above, there is an advantage of improving the signal-to-noise ratio (SNR). In addition, the charge amount sensing device of the multi-touch panel has an advantage of amplifying by accumulating the amount of charge according to the multi-touch state of the multi-touch panel, thereby ensuring sufficient sensitivity even with small charge amount changes. In addition, the amount of charge sensing device of the multi-touch panel is the dynamic range of the system including the touch panel and the amount of charge sensing device of the touch panel by eliminating the offset charge in the amount of charge according to the multi-touch state of the multi-touch panel and accumulating and adjusting the gain. (dynamic range) has the advantage of ensuring the maximum.

BRIEF DESCRIPTION OF THE DRAWINGS In order to better understand the drawings cited in the detailed description of the invention, a brief description of each drawing is provided.
1 is a block diagram of an apparatus for detecting a charge amount of a multi-touch panel according to an embodiment of the inventive concept.
FIG. 2 is a circuit diagram illustrating an embodiment of a charge amount sensing device of the multi-touch panel of FIG. 1.
3 is a waveform diagram of signals used in the amount of charge sensing device of the multi-touch panel of FIG. 2.
4 is a block diagram of an apparatus for detecting a charge amount of a multi-touch panel according to another exemplary embodiment of the inventive concept.
FIG. 5 is a circuit diagram illustrating an example embodiment of a charge detection device of the multi-touch panel of FIG. 4.
FIG. 6 is a waveform diagram of signals used in the charge detection device of the multi-touch panel of FIG. 5.
7 is a view for explaining the change in the amount of charge according to the touch state of the conductor when the capacitance sensor of FIG. 1 or FIG. 4 according to an embodiment.
FIG. 8 is a diagram illustrating a difference between noise when amplifying the sensed charge amount and accumulating the sensed charge amount or the corrected charge amount.

In order to fully understand the present invention, operational advantages of the present invention, and objects achieved by the practice of the present invention, reference should be made to the accompanying drawings and the accompanying drawings which illustrate preferred embodiments of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the preferred embodiments of the present invention with reference to the accompanying drawings. Like reference symbols in the drawings denote like elements.

1 is a block diagram of an apparatus 100 for detecting a charge amount of a touch panel according to an embodiment of the inventive concept.

Referring to FIG. 1, the charge detection device 100 of a touch panel includes a signal transmitter 110, a capacitance sensor 120, a signal receiver 130, a mux 145, and an analog to digital (AD) converter 140. It may be provided.

The signal transmitter 110 may generate and output sensing signals SEN1,..., SENj including information on a sampling time point. Each of the sensing signals SEN1,..., SENj is a sinusoidal signal having a first logic state and a second logic state, or a first logic state and a second logic state in a period in which the signal receiver 130 samples and accumulates charge amounts. May be a repeated signal, and the information on the sampling time point may be a time point at which a logic state is changed among the sensing signals SEN1, ..., SENj. For example, the point in time when the sensing signal SEN1 is changed from the first logic state to the second logic state is the sampling time point, or the point in time when the sensing signal SEN1 is changed from the second logic state to the first logic state. It may be the sampling time point. In the following description, it is assumed that the first logic state is a logic low state and the second logic state is a logic high state. However, the present invention is not limited to this case and conversely, the first logic state may be a logic high state and the second logic state may be a logic low state.

In addition, the signal transfer unit 110 may correspond to the sensing signals SEN1 corresponding to the corresponding input terminals among the input terminals IN1,..., INj (j is a natural number) of the capacitance sensor 120 in response to the input selection signal IN_SEL. ,…, SENj) may transmit a corresponding sensing signal. For example, the signal transmitter 110 may select the input terminals IN1,..., INj of the capacitance sensor 120 one by one in response to the input selection signal IN_SEL, and sequentially transmit corresponding sensing signals. An embodiment of the configuration of the signal transmitter 110 will be described in more detail with reference to FIG. 2.

The capacitance sensor 120 receives a corresponding sensing signal output from the signal transmission unit 110 through a corresponding input terminal among the input terminals IN1,..., INj, and responds to the received sensing signal of the multi-touch panel. The charge amount Q or Q + ΔQ according to the touch state may be output in parallel through the output terminals OUT1,..., And OUTk. That is, the capacitance sensor 120 may be a mutual capacitance sensor that senses and outputs the amount of charge between the input terminals IN1,..., INj and the output terminals OUT1,..., OUTk. The multi-touch panel may include all of a touch key and a touch screen capable of detecting a touch of a conductor (for example, a finger or a pen). Hereinafter, the term 'touch' is referred to as the capacitance sensor 120. This means that the conductor is in close proximity or direct contact with the multi-touch panel so that the amount of charge output is changed. Also, for convenience of description, when the conductor does not touch the multi-touch panel, the amount of charge output from the capacitance sensor 120 is defined as 'Q', and when the conductor touches the multi-touch panel. The amount of charge output from the capacitance sensor 120 is defined as 'Q + ΔQ'. ΔQ may have a positive value or a negative value. The amount of charge sensed by the capacitance sensor 120 according to the touch state will be described in more detail with reference to FIG. 7 or 8.

The signal receiver 130 samples and accumulates the charge amounts Q or Q + ΔQ output in parallel from the capacitance sensor 120 n times (n is a natural number) and adjusts gains to remove noise. The voltages V1 or V2 corresponding to the gain-adjusted accumulated charge amount may be output in parallel. The signal receiver 130 may include a plurality of sampling units 131_1,..., 131_k, a plurality of charge accumulation units 133_1,..., 133_k, and a gain controller 135.

Each of the plurality of sampling units 131_1,..., 131_k is an output terminal of the capacitance sensor 120 in response to the first sampling control signal SCON1 and the second sampling control signal SCON2 including information on the number of sampling times. The amount of charges Q or Q + ΔQ output from the corresponding output terminal among the OUT1, ..., OUTk may be sampled n times. For example, the sampling unit 131_1 may output a charge amount Q or Q output from the corresponding output terminal OUT1 of the capacitance sensor 120 in response to the first sampling control signal SCON1 and the second sampling control signal SCON2. + ΔQ) can be sampled n times, and the sampling unit 131_k is connected at the corresponding output terminal OUTk of the capacitance sensor 120 in response to the first sampling control signal SCON1 and the second sampling control signal SCON2. The output charge amount Q or Q + ΔQ may be sampled n times.

The first sampling control signal SCON1 and the second sampling control signal SCON2 may have opposite phases. The information about the number of sampling may be determined as the number of times the logic state of the first sampling control signal SCON1 or the second sampling control signal SCON2 is changed. For example, the information on the number of times of sampling is the number of times that the second sampling control signal SCON2 is changed from the first logic state to the second logic state or the second sampling control signal SCON2 is first in the second logic state. It can be determined by the number of times to change to a logic state. An embodiment of the sampling units 131_1,..., 131_k will be described in more detail with reference to FIG. 2.

The gain controller 135 generates a plurality of gain control signals GCON using the digital signal Vo output from the AD converter 140 and outputs the plurality of gain control units 133_1,..., 133_k. can do. That is, the gain control unit 135 generates and outputs gain control signals GCON that can adjust the degree of amplification of the charge accumulation units 133_1,..., 133_k according to the output digital signal Vo.

Each of the charge accumulation units 133_1,..., 133_k accumulates the amount of charges sampled n times in the corresponding sampling unit among the sampling units 131_1, ..., 131_k, and adjusts gain to remove noise and adjust gain. The voltage V1 or V2 corresponding to the accumulated accumulation amount can be output. That is, by accumulating the charge amount sampled n times in each of the charge accumulation units 133_1,..., 133_k, the noise is averaged as the noise having a positive value and the noise having a negative value are canceled to minimize noise. And may have the effect of amplification by accumulation.

In addition, each of the charge accumulation units 133_1,..., 133_k may adjust the gain of the voltage V1 or V2 corresponding to the accumulated charge amount in response to the gain control signals GCON. That is, each of the charge accumulation units 133_1,..., 133_k includes a voltage V11 or V21 corresponding to the accumulated charge amount when the input voltage of the AD converter 140 exceeds the input voltage range of the AD converter 140. .., V1k or V2k) is reduced within the input voltage range, and when the input voltage of the AD converter 140 is too small to obtain the desired value, the voltage corresponding to the accumulated charge amount (V11 or V21, ..., V1k Alternatively, the gain of the voltages V11 or V21,..., V1k or V2k corresponding to the accumulated charge amount may be adjusted to increase V2k) within the input voltage range. An embodiment of the charge accumulation unit 133 will be described in more detail with reference to FIG. 2.

The mux 145 may sequentially select and output voltages output from the signal receiver 130 in response to the voltage selection signal OUT_SEL. The voltages V11 or V21,..., V1k or V2k output from the charge accumulation units 133_1,..., 133_k may be simultaneously applied to the mux 145 in parallel, in this case, the mux 145. In response to the voltage selection signal OUT_SEL, one may sequentially select and output one by one to the AD converter 140. For example, the mux 145 outputs the voltage V11 or V21 output from the charge accumulation unit 133_1 to change the digital signal Vo from the AD converter 140 and then outputs the next charge accumulation unit. By repeatedly transmitting the voltage to the AD converter 140, all of the input voltages V11 or V21,..., V1k or V2k may be sequentially output to the AD converter 140. The operation of the mux 145 will be described in more detail with reference to FIGS. 2 and 3.

The AD converter 140 may convert the voltages V11 or V21,..., V1k or V2k sequentially output from the mux 145 into digital signals Vo. Although the digital signal is represented by Vo in the drawing, Vo may include a plurality of bits having different values according to input voltages V11 or V21,..., V1k or V2k. The digital signal Vo converted by the AD converter 140 may be used for an application.

2 is a circuit diagram illustrating an embodiment of the charge amount sensing device 100 of the multi-touch panel of FIG. 1, and FIG. 3 is a waveform diagram of signals used in the charge amount sensing device 100 of the multi-touch panel of FIG. 2. . Hereinafter, an embodiment of each component and an operation of each component of the charge amount sensing device 100 of the multi-touch panel will be described with reference to FIGS. 1 to 3.

The signal transmitter 110 may include a sensing controller 260, a plurality of sensing drivers 263_1,..., 263_j, and a plurality of sensing signal output units 265_1,..., 265_j. The sensing controller 250 may generate and output a sensing control signal SECON in response to the digital signal Vo output from the AD converter 140. Each of the sensing drivers 263_1,..., 263_j is enabled or disabled in response to the input selection signal IN_SEL, and in response to the sensing control signal SECON when enabled in response to the input selection signal IN_SEL. At least one driving signal for controlling the sensing signal output unit 265 may be generated and output to a corresponding sensing signal output unit among the sensing signal output units 265_1 to 265_j.

Each of the sensing drivers 263_1,..., 263_j may include at least one driver for generating at least one driving signal. For example, as illustrated in FIG. 2, each of the sensing drivers 263_1,..., 263_j may include a first driver DR1 and an NMOS transistor N1 that generate a driving signal for turning on or off the PMOS transistor P1. ) May be provided with a second driver DR2 that generates a driving signal for turning on or off. The first driver DR1 and the second driver DR2 may output signals having opposite logic states. Alternatively, one driving signal is output from each of the sensing drivers 253_1,..., And 253_j and applied to the gates of the PMOS transistor P1 and the NMOS transistor N1 so that one of the PMOS transistor P1 and the NMOS transistor N1 is provided. It can also be controlled to turn on only transistors.

Each of the sensing signal output units 265_1,..., 265_j has a first voltage VH in a first logic state or a second voltage in a second logic state in response to the at least one driving signal received from a corresponding sensing driver. The sensing signal SEN1,..., Or SENj of the VL may be output. As illustrated in FIG. 3, each of the sensing signals SEN1,..., And SENj has a first voltage VH in a section in which a corresponding input selection signal among the input selection signals IN_SEL1, ..., IN_SELj is in a second logic state. The first logic state and the second logic state of the second voltage (VL) may be a sine wave signal is repeated. For example, each of the sensing signal output units 265_1,..., 265_j is connected to the PMOS transistor P1 and the NMOS in series between the first voltage VH and the second voltage VL, as shown in FIG. 2. It may be an inverter including the transistor N1.

In the above, an embodiment of the signal transmission unit 110 has been described with reference to FIG. 2, but the signal transmission unit 110 of the present invention is not limited thereto, and the signal reception unit 130 samples the charges. If the first logic state and the second logic state are generated in the accumulating section, the signal may be generated and output to a corresponding input terminal of the capacitance sensor 120.

The capacitance sensor 120 may be modeled as a plurality of capacitors C _MUT1 , ..., C _MUTk connected between the input terminals IN1, ..., INj and the output terminals OUT1, ..., OUTk. The amount of charge of Q or Q + ΔQ may be output through the corresponding output terminal among the output terminals OUT1,... And OUTk according to the touch state.

Each of the sampling units 131_1,..., And 131_k includes a first sampling switching unit 210 to sample an amount of charge output through a corresponding output terminal among the output terminals OUT1, ..., OUTk of the capacitance sensor 120. ) And the second sampling switching unit 220. Since the first sampling switching unit 210 and the second sampling switching unit 220 included in each of the sampling units 131_1,..., 131_k may have the same configuration, the sampling unit 131_1 will be described below for convenience of description. The first sampling switching unit 210 and the second sampling switching unit 220 included in) will be described.

The first sampling switching unit 210 may connect or disconnect the output terminal OUT1 of the capacitance sensor 120 and the ground voltage source VSS in response to the first sampling control signal SCON1. The second sampling switching unit 220 may sample and output the amount of charge output from the output terminal OUT1 of the capacitance sensor 120 to the output of the sampling unit 131_1 in response to the second sampling control signal SCON2. That is, the second sampling switching unit 220 may connect or disconnect the output terminal OUT1 of the capacitance sensor 120 and the input terminal of the charge accumulation unit 133_1 in response to the second sampling control signal SCON2. The first sampling switching unit 210 and the second sampling switching unit 220 are selectively operated, and the signal receiving unit 130 is described with respect to the operations of the first sampling switching unit 210 and the second sampling switching unit 220. It will be described in more detail while explaining the overall operation of.

The charge accumulation units 133_1,..., 133_k may include the operational amplifier 250, the initialization switching unit 230, the plurality of capacitors C1,..., Cn, and the plurality of gain control switching units 240_1. 240_n). The operational amplifier 250, the initialization switching unit 230, the plurality of capacitors C1, ..., Cn, and the plurality of gain control switching units included in each of the charge accumulation units 133_1,..., 133_k Since 240_1,..., 240_n may have the same configuration, the operational amplifier 250, the initialization switching unit 230, and the plurality of capacitors C1 included in the charge accumulation unit 133_1 will be described below for convenience of description. , ..., Cn) and a plurality of gain control switching units 240_1, ..., 240_n.

The operational amplifier 250 muxes the input terminal (-) connected to the output terminal of the sampling unit 131_1, the ground voltage input terminal (+) connected to the ground voltage source VSS, and the voltage V11 or V21 corresponding to the accumulated charge amount. It may include an output terminal for output to (145). The initialization switching unit 230 may connect or disconnect the input terminal (−) and the output terminal of the operational amplifier 250 in response to the initialization signal RST. That is, when the touch state of the multi-touch panel changes or when the charge amount is sampled and accumulated n times, the initialization switching unit 230 connects the input terminal (-) and the output terminal of the operational amplifier 250 to the accumulated charge amount. The voltage V11 or V21 corresponding to may be initialized.

Capacitors C1, ..., Cn are connected in parallel between the input terminal (-) and the output terminal of the operational amplifier 250, and corresponding gain control switching among the gain control switching units 240_1, ..., 240_n. It may be connected between the input terminal (−) of the additional operational amplifier 250 and the corresponding capacitor or between the output terminal of the operational amplifier 250 and the corresponding capacitor. That is, each of the gain control switching units 240_1, ..., 240_n may correspond to an input terminal (−) of the operational amplifier 250 in response to a corresponding gain control signal among the gain control signals GCON_1,..., CGCON_n. Corresponding capacitors can be connected or disconnected between output stages. That is, the number of capacitors connected between the input terminal (−) and the output terminal of the operational amplifier 250 using the gain control signals GCON_1,..., CGCON_n and the gain control switching units 240_1,..., 240_n. By adjusting, the amount of charges sampled by the sampling unit 131_1 may be accumulated and gain may be adjusted.

As the capacitance sum of the capacitors connected between the input terminal (−) and the output terminal of the operational amplifier 250 decreases, the voltage V11 or V21 output from the charge accumulation unit 133_1 increases, and the input terminal of the operational amplifier 250 ( As the capacitance sum of the capacitors connected between-) and the output terminal increases, the voltage V11 or V21 output from the charge accumulation unit 133_1 decreases. Accordingly, as the number of gain control switching units turned on among the gain control switching units 240_1, ..., 240_n is adjusted using the gain control signals GCON_1,..., CGCON_n, the charge accumulation unit ( The voltage V11 or V21 output from 133_1 may be increased or decreased. That is, the gain control unit 135 may increase the voltage V11 or V21 output from the charge accumulation unit 133_1 by using the digital signal Vo output from the AD converter 140. Gain control signals GCON_1,..., GCON_n are generated to reduce the number of the capacitors connected between the input terminal (−) and the output terminal, and use the digital signal Vo output from the AD converter 140. In order to lower the voltage V11 or V21 output from the charge accumulation unit 133_1, the gain control signals may be increased to increase the number of the capacitors connected between the input terminal (−) and the output terminal of the operational amplifier 230. GCON_1, ..., GCON_n) can be generated and printed. As described above, as the gain control switching units 240_1, ..., 240_n are turned on or off in response to the generated gain control signals GCON_1,..., GCON_n, the charge accumulation unit 133_1 The amount of charges sampled by the sampling unit 131_1 may be accumulated and gain may be adjusted to generate and output a voltage V11 or V21 corresponding to the accumulated amount of charge. As described above, the operation of adjusting the gain in response to the gain control signals GCON_1,..., And GCON_n is the same in the remaining charge accumulation unit.

Hereinafter, an operation of the charge amount detecting device 100 of the multi-touch panel will be described with reference to FIGS. 1 to 3.

When the multi-touch panel is initialized to recognize a touch state (for example, when power is applied to the multi-touch panel), when the touch state of the multi-touch panel is changed or the amount of charge is sampled n times. When accumulated, the initialization signal RST is changed from the first logic state to the second logic state so that the initialization switching unit 230 is turned on. In this case, since the input terminal (−) and the output terminal of the operational amplifier 250 are directly connected, the output of the charge accumulation units 133_1,..., 133_k is initialized to the ground voltage.

Subsequently, in the period in which the input selection signal IN_SEL1 is in the second logic state, the capacitance sensor 120 outputs charge amounts corresponding to the touch state of the multi-touch panel in response to the sensing signal SEN1. As described above, the capacitance sensor 120 may output a charge amount of Q when the conductor does not touch the multi-touch panel, and output a charge amount of Q + ΔQ when the conductor touches the multi-touch panel. . For example, the capacitance sensor 120 has first to fourth output terminals, and the conductor touches a portion corresponding to the first and second output terminals of the multi-touch panel and the conductor touches a portion corresponding to the third, fourth and output terminals. If not, the first and second output terminals of the output terminals of the capacitance sensor 120 may output a charge amount of Q + ΔQ, and the third and fourth output terminals may simultaneously output a charge amount of Q in parallel.

The time point at which the sensing signal SEN1 is changed from the first logic state to the second logic state is a time point for sampling the amount of charges output from the capacitance sensor 120, and the signal receivers 133_1,. Among the charge accumulation periods, the time point when the sensing signal SEN1 changes from the first logic state to the second logic state during sampling and accumulation of the corresponding charge amount is the second sampling control signal SCON_2 from the first logic state to the second logic state. Same as when it is changed to state. That is, the sensing signal SEN1 and the second sampling control signal SCON_2 have the same phase in a period in which each of the signal receivers 133_1,..., 133_k samples and accumulates the corresponding charge amounts, and has the same phase. The control signal CON_1 and the second sampling control signal SCON_2 may have opposite phases.

That is, when the first sampling control signal SCON_1 is in the second logic state and the second sampling control signal SCON_2 is in the first logic state, the first sampling switching unit 210 is turned on and the second sampling switching unit ( 220 is turned off so that the outputs of capacitance sensor 120 are connected to ground voltage source VSS and do not sample the charge amounts. When the first sampling control signal SCON_1 is in the first logic state and the second sampling control signal SCON_2 is in the second logic state, the first sampling switching unit 210 is turned off and the second sampling switching unit 220 is turned on. Each of the outputs of the capacitance sensor 120 is turned on so as to be input to a corresponding charge accumulation unit among charge accumulation units 133_1,..., 133_k to sample the charge amounts. In FIG. 3, the sampling count and the cumulative number n are 4, but the present invention is not limited thereto, and the sampling count and the cumulative number n may be other various times. In the case of FIG. 3, the sampling units 131_1,..., 131_k perform sampling at four times when the second sampling control signal SCON_2 is changed from the first logic state to the second logic state, and the charge accumulation units ( Each of 133_1, ..., 133_k) may accumulate the corresponding sampled charges four times and adjust the gain to output a voltage V11 or V21, ..., V1k or V2k corresponding to the accumulated charge amount. Since the method of accumulating the sampled charge amounts and adjusting the gain has been described in detail above, detailed description thereof will be omitted.

When the charge accumulation units 133_1,..., 133_k output the voltages V11 or V21,..., V1k or V2k in parallel corresponding to the corresponding accumulated charge amounts, the ADC enable signal ADC_EN. Is changed from the first logic state to the second logic state so that the AD converter 140 is enabled and the mux 145 is output from the charge accumulation units 133_1,..., 133_k in response to the voltage selection signal OUT_SEL. The voltages V11 or V21, ..., V1k or V2k are sequentially selected and output one by one. In FIG. 3, one of the voltages V11 or V21,..., V1k or V2k may be selected and output for each section in which the voltage selection signal OUT_SEL is in the second logic state, and the voltage to which the mux 145 is input is selected. The AD converter 140 continues to change the output voltage of the mux 145 to the digital signal Vo until all of the fields V11 or V21, ..., V1k or V2k are output.

As described above, when sampling and accumulating at four times and adjusting gain are performed, the initialization signal RST is changed from the first logic state to the second logic state, and the initialization switch 230 is turned on to operate the operational amplifier 250. Since the input terminal (−) and the output terminal are directly connected, the output of the charge accumulation units 133_1,..., 133_k is initialized to the ground voltage.

The operation described above is related to the case where the sensing signal SEL1 is input to one input terminal (eg, IN1) among the input terminals IN1, ..., INj of the capacitor sensor 120. Such an operation is performed whenever a corresponding sensing signal of the sensing signals SEL1, ..., SELj is input to one of the input terminals IN1, ..., INj of the capacitor sensor 120. Sensing signals corresponding to the input terminals IN1, ..., INj of 120 may be sequentially input.

3 illustrates signals for operating the charge amount sensing device 100 of the multi-touch panel according to an embodiment of the present invention, the charge amount sensing device 100 of the multi-touch panel according to an embodiment of the present invention is shown. Signals for operation do not necessarily have a waveform as shown in FIG. 3, and the signals shown in FIG. 3 may have other waveforms as long as they can operate as described above.

By the above operation, the voltage V11 or V21 output from the charge accumulation unit 133_1 may be expressed by Equation 1 below, and the voltages output from the remaining charge accumulation units may be equally represented.

In Equation 1, CF refers to the sum of capacitances of capacitors connected between the input terminal (−) and the output terminal of the associating amplifier 250 among the capacitors C1,..., Cn. That is, in the state where the conductor is not touched by the multi-touch panel, the voltage V11 is a voltage corresponding to the charge amount obtained by accumulating the charge amount Q n times and adjusting the gain, and in the state where the conductor is touched by the multi-touch panel. The voltage V21 may be a voltage corresponding to the charge amount obtained by accumulating the charge amount Q + ΔQ and adjusting gain.

4 is a block diagram of an apparatus 400 for detecting a charge amount of a multi-touch panel according to another exemplary embodiment of the inventive concept.

Referring to FIG. 4, the electric charge sensing device 400 of the touch panel includes a signal transmitter 410, a capacitance sensor 420, a signal receiver 430, a mux 445, and an analog to digital (AD) converter 440. And an auto calibration unit 450. In comparison with the embodiment of FIG. 1 and the embodiment of FIG. 4, in the embodiment of FIG. 4, an automatic correction unit 450 is added in the embodiment of FIG. 1, and the remaining elements are the same elements. Therefore, hereinafter, description will be made mainly of parts different from the embodiment of FIG. 1, and descriptions overlapping with the embodiment of FIG. 1 will be omitted.

The signal transmitter 410 may generate a sensing signal SEN including information about a sampling time point in response to the input selection signal IN_SEL, and output the sensing signal SEN to a corresponding input terminal among the input terminals of the capacitance sensor 420. The capacitance sensor 420 has an input amount IN for receiving the sensing signal SEN output from the signal transmission unit 110 and a charge amount Q according to a touch state of the multi-touch panel in response to the received sensing signal SEN. Or it may include a plurality of output terminals (OUT1, ..., OUTk) for outputting Q + ΔQ).

The automatic correction unit 450 sets the offset charge amounts Qoff1, ..., Qoffk by using the charge amounts output from the output terminals OUT1, ..., OUTk of the capacitance sensor 420 during the offset charge amount setting period. A plurality of offset control signal groups may be generated and offset charge amounts in each of the charge amounts Q or Q + ΔQ according to the touch state output from the capacitance sensor 120 in a section other than the offset charge amount setting section. A correction charge amount (Q-Qoff1 or Q + ΔQ-Qoff1, ..., Q-Qoffk or Q + ΔQ-Qoffk) from which the corresponding offset charge amount is removed among (Qoff1, ..., Qoffk) can be generated and output. have. The offset control signal groups may include a plurality of offset control signals.

The offset charge amount setting section includes a time point at which a system including the multi-touch panel and the charge amount sensing device 400 of the multi-touch panel is initialized, a time point at which the system is reset, and a power voltage is applied to the multi-touch panel during the system operation. The terminal may be a predetermined section in which a conductor is not touched by the multi-touch panel at a point in time at which application is started or a predetermined time elapses after the offset charge setting section ends. For example, assuming that the multi-touch panel is a liquid crystal panel of a smartphone and the charge detection device 400 of the multi-touch panel is included in the smartphone, when the smartphone is initialized, the smartphone When the power is turned on and the power is applied to the smartphone, the power is supplied to the smartphone, but when the liquid crystal panel of the smartphone is turned off and the power is turned on, or the power of the smartphone is applied. When the offset charge amount is set to be reset at predetermined time intervals, the offset charge may be a predetermined section in which the conductor is not touched by the multi-touch panel when the predetermined time elapses.

During the offset charge setting period, the automatic correction unit 450 may generate the offset control signal groups by using the digital signal Vo output from the AD converter 440. That is, in the offset charge amount setting period, the signal receiver 430 samples and accumulates the charge amounts Q or Q + ΔQ output in parallel from the capacitance sensor 420 n times, and adjusts the gain to adjust noise. The voltages V11 or V21,..., V1k or V2k corresponding to the removed and gain-adjusted accumulated charge amount can be output in parallel, and the mux 445 is in parallel in response to the voltage selection signal OUT_SEL. The voltages V11 or V21,..., V1k or V2k that are sequentially input may be sequentially selected and output. The AD converter 440 converts the voltages sequentially output from the mux 445 into the digital signal Vo during the offset charge amount setting period. In this case, the automatic correction unit 450 generates the offset charge amounts Qoff1, ..., Qoffk using the digital signal Vo output from the AD converter 440 during the offset charge amount setting period. Offset control signal groups may be generated, and offset charge amounts Qoff1, ..., Qoffk may be generated in response to the offset control signal groups. For example, when the AD converter 440 receives the voltage V11 or V21 and converts it into a digital signal Vo, the automatic compensator 450 converts the digital signal (V11 or V21) into a digital signal ( The offset control signal group for generating the offset charge amount Qoff1 may be generated in response to Vo). As another example, when the AD converter 440 receives the voltage V1k or V2k and converts it into a digital signal Vo, the automatic compensator 450 converts the voltage V1k or V2k into a digital signal Vo. The offset control signal group for generating the offset charge amount Qoffk may be generated in response to.

When the offset charge amount setting period ends and the signal receiving unit samples and accumulates the charge amounts, the automatic correction unit 450 outputs the output terminals of the capacitance sensor 420 in response to the offset control signal groups. Correction by removing the corresponding offset charge amount among the offset charge amounts Qoff1, ..., Qoffk from the charge amounts Q or Q + ΔQ according to the touch state output in parallel at (OUT1, ..., OUTk) Charges can be generated and output in parallel. In order to perform such an operation, the automatic correction unit 450 may include an offset control signal generator and an offset compensator. Referring to FIG. 5, an offset control signal generator and an offset compensator will be described with reference to FIG. 5. It demonstrates in more detail.

Each of the offset charges Qoff1, ..., Qoffk has the same charge amount as the charge amount Q output from the capacitance sensor 420 in a state where a conductor is not touched to the multi-touch panel or the multi-touch panel In the state in which the conductor is not touched, it may have a charge amount smaller than the charge amount Q output from the capacitance sensor 420. For example, if the offset charge amount Off1 is equal to the charge amount Q, the corrected charge amount Q− in a state where the conductor is not touched by the multi-touch panel in a section in which the signal receiver samples and accumulates the charge amounts. Qoff1) has a value of '0'.

In the period in which the signal receiver 430 samples and accumulates the charge amounts, the signal receiver 430 may correct the charge amounts Q-Qoff1 or Q + ΔQ-Qoff1,..., Q-Qoffk or Q + ΔQ-Qoffk. Is accumulated n times (n is a natural number), and the gain is adjusted to parallel the voltages V11 or V21, ..., V1k or V2k corresponding to the accumulated amount of noise in which the noise is removed and the gain is adjusted. Can be printed as As described with respect to the automatic correction unit 450, the signal receiver 430 n times the charge amounts Q or Q + ΔQ output in parallel from the capacitance sensor 420 in the offset charge amount setting period. By sampling and accumulating and adjusting gain, the voltages V11 or V21,..., V1k or V2k corresponding to the accumulated amount of noise with noise removed and gain adjusted may be output. . The signal receiver 430 may include a plurality of sampling units 431_1,..., 431_k, a plurality of charge accumulation units 433_1,..., 433_k, and a gain controller 435. Since the operation has been described in detail with reference to FIG. 1, a detailed description thereof will be omitted. That is, except that the charge amounts input to the sampling units 431_1,..., 431_k are changed to the corrected charge amounts, the sampling units 431_1, ..., 431_k, and the charge accumulation units 433_1, ..., 433_k. ) And the gain controller 435 may operate in the same manner as the sampling units 131_1,..., 131_k, the charge accumulation units 133_1,..., 133_k, and the gain controller 435 of FIG. 1.

The mux 445 sequentially selects and outputs voltages output from the signal receiver 430 one by one in response to the voltage selection signal OUT_SEL, and the AD converter 440 converts the output voltage of the mux 445 into a digital signal Vo. Can be converted to

FIG. 5 is a circuit diagram illustrating an embodiment of the charge amount sensing device 400 of the multi-touch panel of FIG. 4, and FIG. 6 is a waveform diagram of signals used in the charge amount sensing device 400 of the multi-touch panel of FIG. 4. . Hereinafter, an embodiment of each component of the charge detection device 400 of the multi-touch panel and an operation of each component will be described with reference to FIGS. 4 to 6. However, as described with reference to FIG. 4, except for the automatic correcting unit 450, the description is similar to that described with reference to FIG. 2, and thus overlapping descriptions will be omitted.

The signal transmitter 410 may include a sensing controller 560, a plurality of sensing drivers 563_1,..., 563_j, and a plurality of sensing signal output units 565_1,..., 565_j, and the sensing controller 560. The sensing drivers 563_1 to 563_j and the sensing signal output units 565_1 to 565_j include the sensing control unit 260, the sensing drivers 263_1 to 263_j, and the sensing signal output units 265_1 of FIG. 2. , ..., 265_j), so detailed description thereof will be omitted below.

The capacitance sensor 320 may be modeled as capacitors C _MUT1 , ..., C _MUTk connected between the input terminals IN1,..., INj and the output terminals OUT1,..., And OUTk. According to the touch state, the charge amount of Q or Q + ΔQ may be output through the corresponding output terminal among the output terminals OUT1,..., And OUTk.

The auto-correction unit 450 uses the digital signal output from the AD converter 440 during the offset charge setting period, and offset control signal groups D11, D12, ..., D1i, ..., Dk1, Dk2. Offset control signal generator 570 for generating Dki) (i is a natural number) and offset control signal groups D11, D12, ..., D1i, ..., Dk1, Dk2, .. , The amount of charge Q or Q + ΔQ according to the touch state output from the corresponding output terminal among the output terminals OUT1, ..., OUTk of the capacitance sensor 420 in response to the corresponding offset control signal group among Dki). ) May include a plurality of offset compensators 575_1,... 575_k that generate and output the correction charges from which the corresponding offset charges of the offset charges Qoff1, ..., Qoffk are removed. The offset control signal groups may include i offset control signals. The method of generating the offset control signal groups D11, D12, ..., D1i, ..., Dk1, Dk2, ..., Dki has been described in detail with reference to FIG. An embodiment of the offset compensators 575_1,..., 575_k disclosed in FIG. 5 will be described. Each of the offset compensators 575_1,..., 575_k is different from each other in that the input offset control signal groups are different. Therefore, the offset compensators 575_1,. Explain.

The offset compensator 575_1 may include a plurality of correction capacitors CA1, CA2,..., CAi and a plurality of offset compensation switches 577_11, 577_12,..., 577_i. Correction capacitors CA1, CA2, ..., CAi have one end connected between an output terminal OUT1 of the capacitance sensor 120 and an input terminal (the input terminal of the sampling unit 431_1) of the signal receiver 440 and offset compensation. The other end of the switches 577_1, 577_2,..., 577_i may be connected to one end of a corresponding offset compensation switch. Each of the correction capacitors CA1, CA2,..., CAi may have a different capacitance value. Each of the offset compensation switches 577_1, 577_2,..., 277_i corresponds to the first voltage source VL and the first voltage in response to a corresponding offset control signal among the offset control signals D11, D12,..., D1i. One voltage source of the two voltage sources VH and the other end of a corresponding correction capacitor among the correction capacitors CA1, CA2,..., CAi may be connected. That is, according to the number of offset compensation switches connected to the first voltage source VL and the number of offset compensation switches connected to the second voltage source VH among the offset compensation switches 577_1, 577_2,..., 577_i. The offset charge amount Q _off 1 may be determined.

Each of the sampling units 431_1,..., 431_k is a charge amount Q or Q + ΔQ or an offset compensating unit output from a corresponding output terminal among the output terminals OUT1,..., And OUTk of the capacitance sensor 420. The first sampling switching unit 510 and the second sampling switching unit 520 may be provided to sample the amount of corrected charges output from the corresponding offset compensators 575_1 to 575_k. The first sampling switching unit 510 and the second sampling switching unit 520 included in the sampling units 431_1,..., 431_k may include the first sampling switching unit 210 and the second sampling switching unit (FIG. 2) of FIG. 2. 220, so the detailed description thereof will be omitted. Each of the charge accumulation units 433_1,..., And 433_k may include an operational amplifier 550, an initialization switching unit 530, a plurality of capacitors C1, ..., Cn, and a plurality of gain control switching units 540_1, ..., 540_n), and the detailed description thereof will be omitted below.

Hereinafter, an operation of the charge amount detecting device 400 of the multi-touch panel will be described with reference to FIGS. 4 to 6.

First, the operation of the charge amount detecting device 400 of the multi-touch panel during the offset charge amount setting period will be described. When the offset setting period starts, the capacitance sensor 420 outputs the amount of charges according to the touch state of the multi-touch panel in response to a corresponding sensing signal among the sensing signals SEN1,..., SENj. , OUTk) can be output in parallel. Hereinafter, it is assumed that the offset charge amount setting section is a section in which the touch of the conductor is not present in the multi-touch panel. Therefore, the capacitance sensor 420 outputs the charge amount Q in a state where the conductor does not touch the multi-touch panel.

The amount of charge Q sensed and output by the capacitance sensor 420 is sampled and accumulated by the signal receiver 430 n times, and the gain is adjusted to remove the noise, and the voltages V11 and. .., V1k) are output in parallel. The mux 445 sequentially selects the voltages V11,..., And V1k input in parallel to the AD converter 440 in response to the voltage selection signal OUT_SEL, and outputs the AD converter 440 to the AD converter 440. May convert the voltages V11,..., Or V1k output from the signal receiver 430 into digital signals Vo and output the converted signals.

The offset control signal generator 570 of the automatic correction unit 450 uses the digital signal Vo to provide the offset control signal groups D11, D12, ..., D1i, ..., Dk1, Dk2, ... , Dki) to output a corresponding offset control signal group to the corresponding offset compensator among the offset compensators 575_1, ..., 575_k, and each of the offset compensators 575_1, ..., 575_k is offset. The offset charge amount Qoff1, ..., or Qoffk in response to the corresponding offset control signal group among the control signal groups D11, D12, ..., D1i, ..., Dk1, Dk2, ..., Dki. ) Can be created. The offset charge amounts Qoff1, ..., Qoffk may be generated by one loop described above, or may be generated by repeating such a loop a plurality of times. Hereinafter, the offset control signal groups D11, D12, ..., D1i, ..., Dk1, Dk2, ..., Dki are generated by the above method, and the offset charge amounts Qoff1, ..., Qoffk. After the) is determined, a section in which the signal receiver 430 samples and accumulates the charges will be described.

When the multi-touch panel is initialized to recognize a touch state (for example, when power is applied to the multi-touch panel), when the touch state of the multi-touch panel is changed or the amount of charge is sampled n times. At the point in time just before the section where the signal receiving unit 430 samples the charge amounts and accumulates the charge, such as in the case of accumulation, the initialization signal RST is changed from the first logic state to the second logic state to initialize the switching unit 530. ) Is turned on. In this case, since the input terminal (−) and the output terminal of the operational amplifier 550 are directly connected, the output of the charge accumulation units 433_1,..., 433_k is initialized to the ground voltage.

Thereafter, in the period in which the input selection signal IN_SEL1 is in the second logic state, the capacitance sensor 420 outputs the amounts of charges according to the touch state of the multi-touch panel in parallel in response to the sensing signal SEN1. As described above, the capacitance sensor 420 may output a charge amount of Q when the conductor does not touch the multi-touch panel, and output a charge amount of Q + ΔQ when the conductor touches the multi-touch panel. . The charge amounts Q or Q + ΔQ output from the output terminals OUT1, ..., OUTk of the capacitance sensor 420 pass through the automatic correction unit 450 and the offset charge amounts Qoff1, ..., or Qoffk. ) Is removed, the automatic correction unit 450 is the correction charge amount (Q−) from which the offset charge amount (Qoff1, ..., or Qoffk) is removed from the charge amount (Q or Q + ΔQ) output from the capacitance sensor 420. Qoff1 or Q + ΔQ-Qoff1, ..., Q-Qoffk or Q + ΔQ-Qoffk) can be output.

As illustrated in FIG. 6, each of the sensing signals SEN1,..., And SENj includes a first logic state and a first logic state in a section in which a corresponding input selection signal among the input selection signals IN_SEL1, ..., IN_SELj is a second logic state. 2 The logic state is a repeating signal. The time point at which the sensing signals SEN1,..., SENj change from the first logic state to the second logic state is a time point for sampling the correction charge amounts, and the signal receiver 430 samples and accumulates the correction charge amounts. The time point at which the corresponding sensing signal is changed from the first logic state to the second logic state is the same as the time point at which the second sampling control signal SCON_2 is changed from the first logic state to the second logic state. That is, the sensing signal and the second sampling control signal SCON_2 have the same phase in the period in which the signal receiving unit 433 samples and accumulates the charges, and the first sampling control signal CON_1 and the second sampling control signal. SCON_2 may have an opposite phase.

That is, when the first sampling control signal SCON_1 is in the second logic state and the second sampling control signal SCON_2 is in the first logic state, the first sampling switching unit 510 is turned on and the second sampling switching unit ( The 520 is turned off so that the output of the capacitance sensor 420 is connected to the ground voltage source VSS and does not sample the corrected charge amount. When the first sampling control signal SCON_1 is in the first logic state and the second sampling control signal SCON_2 is in the second logic state, the first sampling switching unit 510 is turned off and the second sampling switching unit 520 is turned on. When turned on, the output of the capacitance sensor 420 may be input to a corresponding charge accumulation unit among charge accumulation units 433_1,..., And 433_k to sample the corrected charge amount. In FIG. 6, the sampling number and the cumulative number n are 4, but the present invention is not limited thereto, and the sampling number and the cumulative number n may be other various times. In the case of FIG. 6, the sampling units 431_1,..., 431_k perform sampling at four times when the second sampling control signal SCON_2 is changed from the first logic state to the second logic state, and the charge accumulation units ( 433_1,..., 433_k) may accumulate the charge amounts sampled four times and adjust gain to output voltages V11 or V21,..., V1k or V2k corresponding to the accumulated charge amount. Since the method of accumulating the sampled charge amounts and adjusting the gain has been described in detail above, detailed description thereof will be omitted.

When each of the charge accumulation units 433_1, ..., 433_k outputs a corresponding voltage among the voltages V11 or V21, ..., V1k or V2k, the ADC enable signal ADC_EN is in the first logic state. The AD converter 440 is enabled and the mux 445 is outputted from the charge accumulation units 433_1, ..., 433_k in response to the voltage selection signal OUT_SEL. Or V21, ..., V1k or V2k) are selected one by one and output. In FIG. 6, one of the voltages V11 or V21,..., V1k or V2k may be selected and output for each section in which the voltage selection signal OUT_SEL is in the second logic state, and the voltage to which the mux 345 is input. The AD converter 340 continues to change the output voltage of the mux 345 to the digital signal Vo until all of the fields V11 or V21, ..., V1k or V2k are output.

As described above, when sampling and accumulating and gain are adjusted at four times, the initialization signal RST is changed from the first logic state to the second logic state, and the initialization switching unit 530 is turned on to operate the operational amplifier 550. Since the input terminal (−) and the output terminal are directly connected, the output of the charge accumulation units 433_1,..., 433_k is initialized to the ground voltage.

In FIG. 3, when V11,..., Or V1k has a constant value, the offset charge amount Qoff corresponds to the charge amount Q without the conductor touching the multi-touch panel. That is, when the offset charge amount Qoff is the same as the charge amount Q when the conductor is not touched by the multi-touch panel, the corrected charge amount becomes '0' in a section where the conductor is not touched by the multi-touch panel. In addition, the voltage (V11, ..., or V1k) corresponding to the accumulated charge amount obtained by sampling and accumulating the gain is also set to '0'.

The operation described above is related to the case where the sensing signal SEL1 is input to one input terminal (eg, IN1) among the input terminals IN1, ..., INj of the capacitor sensor 420. Such an operation is performed whenever a corresponding sensing signal of the sensing signals SEL1, ..., SELj is input to one of the input terminals IN1, ..., INj of the capacitor sensor 420. Sensing signals corresponding to the input terminals IN1, ..., INj of 420 may be sequentially input.

3 illustrates signals for operating the charge amount sensing device 100 of the multi-touch panel according to an embodiment of the present invention, the charge amount sensing device 100 of the multi-touch panel according to an embodiment of the present invention is shown. Signals for operation do not necessarily have a waveform as shown in FIG. 3, and the signals shown in FIG. 3 may have other waveforms as long as they can operate as described above.

By the above operation, the voltage V11 or V21 output from the charge accumulation unit 433_1 may be expressed by Equation 2 below, and the voltages output from the remaining charge accumulation units may be equally represented.

In Equation 2, C _F represents the sum of capacitances of the capacitors connected between the input terminal (−) and the output terminal of the associative amplifier 550 among the capacitors C1,..., Cn, and D1 to Di are the offsets. The value set in the setting section may have a value of '0' or '1'. That is, the voltage V11 is a voltage corresponding to the charge amount obtained by accumulating the corrected charge amount Q-Qoff1 n times and adjusting the gain while the conductor is not touched by the multi-touch panel, and the conductor touches the multi-touch panel. In this state, the voltage V21 may be a voltage corresponding to the charge amount obtained by accumulating the corrected charge amount Q + ΔQ−Qoff1 n times and adjusting the gain.

FIG. 7 is a diagram for describing a change in charge amount according to a touch state of a conductor when the capacitance sensor 120 of FIG. 1 or the capacitance sensor 420 of FIG. 4 is used.

1 through 7, in the capacitance sensor 120 or 420, a plurality of input terminals IN1 and IN2 and a plurality of output terminals OUT1, OUT2, and OUT3 may be formed on different planes. That is, each of the input terminals share the output terminals. When the conductor is not touched by the multi-touch panel, a charge amount of Q is generated between the input terminal and the output terminal to output the charge amount of Q to the output terminal. However, when the conductor is touched by the multi-touch panel, a charge amount of Q + ΔQ is generated between the input terminal IN and the output terminals OUT1 and OUT3, so that the charge amount of Q + ΔQ is transmitted to the output terminals OUT1 and OUT3. Output

 FIG. 7 illustrates a case in which three outputs are provided at one input terminal IN1 or IN2. However, the present invention is not limited thereto, and k output terminals may be provided at one input terminal as described with reference to FIGS. 1 to 6. This may be included. In addition, as shown in FIG. 7, the number of input terminals may be different from two. In this case, as described in connection with the embodiment of FIGS. 1 to 3 or the embodiment of FIGS. The amount of charge can be detected by performing an operation.

The structure of the capacitance sensor 120 or 420 of FIG. 7 is merely an embodiment of the present invention, and the capacitance sensor 120 or 420 of the present invention is not limited to the structure of FIG. 7. That is, the capacitance sensor 120 or 420 may have various other structures if the amounts of charges according to the touch state of the multi-touch panel can be output in response to a sensing signal applied to the input terminal with the input terminals and output terminals.

FIG. 8 is a diagram illustrating a difference between noise when amplifying the sensed charge amount and accumulating the sensed charge amount or the corrected charge amount.

1 to 8, in the case of simply amplifying the amount of charge sensed by the capacitance sensor, the noise is amplified by an amplification ratio (A). However, the charge amount or the correction charge amount according to an embodiment of the present invention is sampled and accumulated. In this case, the positive and negative components of the noise are canceled by accumulation, and the noise has an average value. Therefore, compared to the case of simply amplifying the sensed charge amount, according to an embodiment of the inventive concept, the signal to noise ratio (SNR) may be improved by minimizing noise.

As described above, optimal embodiments have been disclosed in the drawings and the specification. Although specific terms have been employed herein, they are used for purposes of illustration only and are not intended to limit the scope of the invention as defined in the claims or the claims. Therefore, those skilled in the art will appreciate that various modifications and equivalent embodiments are possible without departing from the scope of the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

Claims (21)

A signal transfer unit configured to output a sensing signal including information on a sampling time point to corresponding ones of the input terminals of the capacitance sensor in response to the input selection signal;
The capacitance sensor receiving the sensing signal through the corresponding input terminal and outputting, in parallel, a plurality of output terminals the charge amounts according to the touch state of the multi-touch panel in response to the received sensing signal;
Sampling the amount of charges output in parallel from the capacitance sensor n times (n is a natural number), accumulating and controlling gain to remove noise and output voltages in parallel corresponding to the gain-adjusted accumulated charges. A signal receiving unit;
A mux for sequentially selecting and outputting voltages output from the signal receiver in response to a voltage selection signal; And
And an AD (analog to digital) converter for converting the voltage sequentially output from the MUX into a digital signal and sequentially outputting the converted voltage. The method of claim 1, wherein the signal receiving unit,
A gain controller configured to generate and output a plurality of gain control signals using the digital signal output from the AD converter;
A plurality of sampling units configured to sample the amount of charge output from a corresponding output terminal among the output terminals of the capacitance sensor n times in response to the first sampling control signal and the second sampling control signal including information about the number of sampling; And
And a plurality of charge accumulation units configured to accumulate the n-th sampled charge amounts in a corresponding one of the sampling units in response to the gain control signals, and adjust a gain to output a voltage corresponding to the accumulated charge amount. Charge amount sensing device of a multi-touch panel. The method of claim 2, wherein each of the sampling units,
A first sampling switching unit for connecting or disconnecting a corresponding output terminal of the capacitance sensor and a ground voltage source in response to the first sampling control signal; And
A second sampling switching unit configured to sample and output an amount of charge output from a corresponding output terminal of the capacitance sensor in response to the second sampling control signal,
And the first sampling switching unit and the second sampling switching unit selectively operate. The method of claim 3, wherein the sensing signal,
A first logic state and a second logic state are repeated in a section in which the signal receiver samples and accumulates the charge amounts;
The second sampling control signal,
A signal having the same phase as the sensing signal in a section in which the signal receiver samples and accumulates the charge amounts;
The first sampling control signal,
And a signal having a phase opposite to that of the second sampling control signal. The method of claim 4, wherein the first sampling switching unit,
In the period in which the signal receiving unit samples and accumulates the charges, when the first sampling control signal is in a first logic state, the ground voltage source is connected to a corresponding output terminal of the capacitance sensor, and the first sampling control signal is formed by the first sampling control signal. 2 disconnects the ground voltage source from the corresponding output terminal of the capacitance sensor;
The second sampling switching unit,
In the period in which the signal receiving unit samples and accumulates the charge amounts, when the second sampling control signal is in the first logic state, the connection between the corresponding output terminal of the capacitance sensor and the input terminal of the corresponding charge amount accumulating unit is disconnected and the second sampling is performed. And a corresponding output terminal of the capacitance sensor and an input terminal of the corresponding charge accumulation unit when the control signal is in the second logic state. The method of claim 2, wherein each of the charge accumulation units,
An operational amplifier including an input terminal connected to an output terminal of the corresponding sampling unit, a ground voltage input terminal connected to a ground voltage source, and an output terminal outputting a voltage corresponding to the accumulated charge amount to the mux;
When the touch state of the multi-touch panel is changed or when the amount of charge is accumulated by n times in the corresponding sampling unit, the voltage corresponding to the accumulated amount of charge is connected by connecting an input terminal and an output terminal of the operational amplifier in response to an initialization signal. Initialization switching unit for initializing the;
A plurality of capacitors connected in parallel between an input terminal and an output terminal of the operational amplifier; And
And a plurality of gain control switching units for connecting or disconnecting each of the capacitors between an input terminal and an output terminal of the operational amplifier in response to a corresponding gain control signal among the gain control signals. Sensing device. The method of claim 6, wherein the gain control unit,
When the voltage corresponding to the accumulated charge amount is to be increased, the number of the capacitors connected between the input terminal and the output terminal of the operational amplifier is decreased, and when the voltage corresponding to the accumulated charge amount is to be decreased, the input terminal and the output terminal of the operational amplifier are reduced. And generating the gain control signals to increase the number of the capacitors connected therebetween. The method of claim 1, wherein the signal transmission unit,
The signal receiving unit generates and outputs the sensing signal in which a first logic state and a second logic state are repeated in a section in which the charge amounts are sampled and accumulated,
Wherein the signal receiver comprises:
And an amount of charge output from the capacitance sensor when the sensing signal changes from the first logic state to the second logic state. The method of claim 1, wherein the signal transmission unit,
A sensing controller configured to generate and output a sensing control signal in response to the digital signal output from the AD converter;
A plurality of sensing drivers enabled in response to the input selection signal and generating and outputting at least one driving signal in response to the sensing control signal; And
And a plurality of sensing signal output units configured to generate the sensing signal in response to the at least one driving signal and output the sensing signal to a corresponding one of the input terminals of the capacitor. A signal transfer unit configured to output a sensing signal including information on a sampling time point to corresponding ones of the input terminals of the capacitance sensor in response to the input selection signal;
The capacitance sensor receiving the sensing signal through the corresponding input terminal and outputting, in parallel, a plurality of output terminals the charge amounts according to the touch state of the multi-touch panel in response to the received sensing signal;
During the offset charge setting period, a plurality of offset control signal groups for setting offset charge amounts corresponding to each charge amount are generated by using the charge amounts output from each of the output terminals of the capacitance sensor, and in response to the offset control signal groups An automatic correction unit configured to generate correction charge amounts in which the offset charge amounts of the offset charge amounts are removed from each of the charge amounts output in parallel from the capacitance sensor and output in parallel;
A signal receiver configured to sample and accumulate each of the corrected charge amounts n times (n is a natural number) and adjust gain to output voltages corresponding to the accumulated charge amounts in which noise is removed and gain is adjusted in parallel;
A mux for sequentially selecting and outputting voltages output from the signal receiver in response to a voltage selection signal; And
And an AD (analog to digital) converter for converting the voltage sequentially output from the MUX into a digital signal and sequentially outputting the converted voltage. The method of claim 10, wherein the signal receiving unit,
Sampling and accumulating the charges output in parallel in the capacitance sensor n times during the offset charge setting period, and adjust the gain (output) to remove the noise and output voltages corresponding to the gain-adjusted accumulated charge amount,
The mux,
In response to the voltage selection signal during the offset charge amount setting period, the voltages output from the signal receiver are sequentially selected and output one by one,
The AD converter,
Converts the voltage output from the MUX into a digital signal during the offset charge amount setting period, and outputs the digital signal;
The automatic correction,
An offset control signal generator configured to generate the offset control signal groups corresponding to respective charge amounts output from the capacitance sensor using the digital signal output from the AD converter during the offset charge amount setting period; And
A plurality of generating and outputting the correction charge amount by removing the corresponding offset charge amount of the offset charge amounts from the corresponding charge amount of the charge amounts output from the capacitance sensor in response to the corresponding offset control signal group among the offset control signal groups Charge amount sensing device of the multi-touch panel characterized in that it comprises offset compensation parts. The method of claim 11, wherein each of the offset compensation unit,
A plurality of correction capacitors having one end connected between a corresponding output terminal among the output terminals of the capacitance sensor and a corresponding input terminal among the input terminals of the signal receiver; And
In response to a corresponding offset control signal of the corresponding offset control signal group, a plurality of offset compensation switching unit for connecting a voltage source of one of the first voltage source and the second voltage source and the other end of the corresponding correction capacitor of the correction capacitors; Charge amount sensing device of the multi-touch panel characterized in that it comprises. The method of claim 10, wherein the offset charge amount setting section,
When the system including the multi-touch panel and the charge amount sensing device of the multi-touch panel is initialized, when the system is reset, when the power voltage starts to be applied to the multi-touch panel during the system operation or the offset charge amount is set And a predetermined period in which a conductor is not touched by the multi-touch panel when a predetermined time elapses after the end of the section. The method of claim 10, wherein the offset charge amount,
The charge amount sensing device of the multi-touch panel, characterized in that the amount of charge less than or equal to the amount of charge output from the capacitance sensor in the state that the conductor is not touched to the multi-touch panel. The method of claim 10, wherein the signal receiving unit,
A gain controller configured to generate and output a plurality of gain control signals using the digital signal output from the AD converter;
A plurality of sampling units for sampling a corresponding correction charge amount n times among correction charge amounts output from the automatic correction unit in response to a first sampling control signal and a second sampling control signal including information about the number of sampling; And
And a plurality of charge accumulation accumulators for accumulating the charge amounts sampled n times in the corresponding ones of the sampling units in response to the gain control signals and adjusting a gain to output a voltage corresponding to the accumulated charge amount. Charge amount sensing device of a multi-touch panel. The method of claim 15, wherein each of the sampling unit,
A first sampling switching unit connecting or disconnecting a corresponding output terminal of the automatic correction unit and a ground voltage source in response to the first sampling control signal; And
A second sampling switching unit for sampling and outputting a correction charge amount output from the corresponding output terminal of the automatic correction unit in response to the second sampling control signal,
And the first sampling switching unit and the second sampling switching unit selectively operate. The method of claim 16, wherein the sensing signal,
A first logic state and a second logic state are repeated in a section in which the signal receiver samples and accumulates the charge amounts;
The second sampling control signal,
A signal having the same phase as the sensing signal in a section in which the signal receiver samples and accumulates the charge amounts;
The first sampling control signal,
And a signal having a phase opposite to that of the second sampling control signal. The method of claim 15, wherein each of the charge accumulation unit,
An operational amplifier including an input terminal connected to an output terminal of a corresponding sampling unit among the sampling units, a ground voltage input terminal connected to a ground voltage source, and an output terminal outputting a voltage corresponding to the accumulated charge amount to the mux;
When the touch state of the multi-touch panel is changed or when the amount of charge is accumulated by n times in the corresponding sampling unit, the voltage corresponding to the accumulated amount of charge is connected by connecting an input terminal and an output terminal of the operational amplifier in response to an initialization signal. Initialization switching unit for initializing the;
A plurality of capacitors connected in parallel between an input terminal and an output terminal of the operational amplifier; And
And a plurality of gain control switching units for connecting or disconnecting each of the capacitors between an input terminal and an output terminal of the operational amplifier in response to a corresponding gain control signal among the gain control signals. Sensing device. The method of claim 18, wherein the gain control unit,
When the voltage corresponding to the accumulated charge amount is to be increased, the number of the capacitors connected between the input terminal and the output terminal of the operational amplifier is decreased, and when the voltage corresponding to the accumulated charge amount is to be decreased, the input terminal and the output terminal of the operational amplifier are reduced. And generating the gain control signals to increase the number of the capacitors connected therebetween. The method of claim 10, wherein the signal transmission unit,
The signal receiving unit generates and outputs the sensing signal in which a first logic state and a second logic state are repeated in a section in which the charge amounts are sampled and accumulated,
Wherein the signal receiver comprises:
And sensing the amount of correction charges output from the automatic correction unit when the sensing signal changes from the first logic state to the second logic state. The method of claim 10, wherein the signal transmission unit,
A sensing controller configured to generate and output a sensing control signal in response to the digital signal output from the AD converter;
A plurality of sensing drivers enabled or disabled in response to the input selection signal and generating and outputting at least one driving signal in response to the sensing control signal; And
And a plurality of sensing signal output units configured to generate the sensing signal in response to the at least one driving signal and output the sensing signal to a corresponding one of the input terminals of the capacitor.

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