CN107844222B - Touch sensing device - Google Patents
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- CN107844222B CN107844222B CN201610945060.XA CN201610945060A CN107844222B CN 107844222 B CN107844222 B CN 107844222B CN 201610945060 A CN201610945060 A CN 201610945060A CN 107844222 B CN107844222 B CN 107844222B
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- 239000003990 capacitor Substances 0.000 claims description 47
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- 230000003247 decreasing effect Effects 0.000 claims description 6
- 238000010586 diagram Methods 0.000 description 19
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- 239000004020 conductor Substances 0.000 description 2
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
- G06F3/044—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
- G06F3/0416—Control or interface arrangements specially adapted for digitisers
- G06F3/0418—Control or interface arrangements specially adapted for digitisers for error correction or compensation, e.g. based on parallax, calibration or alignment
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Abstract
The invention provides a touch sensing device. The touch sensing device comprises an amplifying circuit, an analog-digital conversion circuit, a processing circuit and a correcting circuit. The amplifying circuit amplifies the touch sensing signal during the touch sensing period. The analog-digital conversion circuit converts the amplified touch sensing signal into a digital signal. The processing circuit judges the touch position according to the digital signal. The correction circuit is controlled by the processing circuit to subtract the signal component of the touch sensing signal for multiple times during the touch sensing period. The invention can effectively remove the background signal and greatly improve the use quality of the touch sensing device.
Description
Technical Field
The present disclosure relates to sensing devices, and particularly to a touch sensing device.
Background
Touch panels are generally classified into resistive touch panels, capacitive touch panels, optical touch panels, acoustic wave touch panels, and electromagnetic touch panels according to their sensing methods. The capacitive touch panel has been widely used in electronic products because of its advantages of fast response time, good reliability, high durability, etc.
The capacitive touch panel is close to or touches the touch panel through a finger or a conductor material, so that the capacitance value of the touch panel is changed. When the touch panel detects the capacitance value change, the position where the finger or the conductor material is close to or touched can be judged, and the functional operation corresponding to the touched position is executed. In a general touch technology, an amplifier is usually used to amplify a touch sensing signal detected by a touch panel, but the touch sensing signal amplified by the amplifier usually includes other background signals, such as background signals generated by background capacitance formed between sensing pads. The background signal is likely to cause the output saturation of the amplifier, and on the same capacitive touch panel, the background signal components contained in the detected touch sensing signals at different positions may be different, or different capacitive touch panels may have different background signal components, so that it is difficult to effectively eliminate the background signal, and the use quality of the capacitive touch panel is reduced.
Disclosure of Invention
The invention provides a touch sensing device, which can effectively remove background signals and greatly improve the use quality of the touch sensing device.
The touch sensing device of the invention comprises an amplifying circuit, an analog-digital conversion circuit, a processing circuit and a correction circuit. The amplifying circuit receives the touch sensing signal from the input end thereof during the touch sensing period, and amplifies the touch sensing signal. The analog-to-digital conversion circuit is coupled to the amplifying circuit and converts the touch sensing signal into a digital signal. The processing circuit is coupled to the analog-digital circuit and determines the touch position according to the digital signal. The correction circuit is coupled to the input terminal of the amplifying circuit and the processing circuit, and is controlled by the processing circuit to subtract the signal component of the touch sensing signal for multiple times during the touch sensing period.
In an embodiment of the invention, the correction circuit changes a decrement of a signal component of the touch sensing signal every time.
In an embodiment of the invention, the decrement of the signal component of the touch sensing signal is decreased in an arithmetic manner or an exponential manner.
In an embodiment of the invention, the calibration circuit includes a current extraction circuit controlled by the processing circuit to extract the current of the input terminal of the amplifying circuit for a plurality of times during the touch sensing period, so as to subtract the signal component of the touch sensing signal for a plurality of times.
In an embodiment of the invention, the current extracting circuit includes a current array for extracting the current of the input terminal of the amplifying circuit a plurality of times according to a digital control signal from the processing circuit.
In an embodiment of the invention, the amplifying circuit includes an amplifier, a capacitor unit and a switch. The positive input end and the negative input end of the amplifier respectively receive the reference voltage and the touch sensing signal, and the output end of the amplifier is coupled with the analog-digital conversion circuit. The capacitor unit is coupled between the negative input end and the output end of the amplifier. The switch is coupled between the negative input terminal and the output terminal of the amplifier, and short-circuits the negative input terminal and the output terminal of the amplifier during the reset period.
The invention further provides a touch sensing device including an amplifying circuit, an analog-to-digital converting circuit, a processing circuit, a capacitor unit, a first switching circuit and a second switching circuit. The amplifying circuit receives the touch sensing signal from the input end thereof during the touch sensing period, and amplifies the touch sensing signal. The analog-to-digital conversion circuit is coupled to the amplifying circuit and converts the touch sensing signal into a digital signal. The processing circuit is coupled to the analog-digital circuit and determines the touch position according to the digital signal. The first switching circuit is coupled among the capacitor unit, the correction voltage and the reference voltage. The second switching circuit is coupled between the capacitor unit, the input terminal of the amplifying circuit and the ground voltage, and during the touch sensing period, the first switching circuit and the second switching circuit are controlled by the processing circuit to switch between a first state and a second state so as to reduce the signal component of the touch sensing signal for multiple times.
In an embodiment of the invention, the capacitance unit is a variable capacitor, and the processing circuit further changes a capacitance value of the capacitance unit to change a decrement of a signal component of the touch sensing signal.
In an embodiment of the invention, the decrement of the signal component of the touch sensing signal is decreased in an arithmetic manner or an exponential manner.
In an embodiment of the invention, the amplifying circuit includes an amplifier, a capacitor unit and a switch. The positive input end and the negative input end of the amplifier respectively receive the reference voltage and the touch sensing signal, and the output end of the amplifier is coupled with the analog-digital conversion circuit. The capacitor unit is coupled between the negative input end and the output end of the amplifier. The switch is coupled between the negative input terminal and the output terminal of the amplifier, and short-circuits the negative input terminal and the output terminal of the amplifier during the reset period.
Based on the above, the touch sensing apparatus according to the embodiment of the invention effectively eliminates the background signal in the detected touch sensing signal at different positions of the same touch panel or the background signal in the detected touch sensing signal of different touch panels by subtracting the signal component of the touch sensing signal received by the amplifying circuit by the correcting circuit for multiple times during the touch sensing period, so as to avoid output saturation of the amplifying circuit and greatly improve the use quality of the touch sensing apparatus.
In order to make the aforementioned and other features and advantages of the invention more comprehensible, embodiments accompanied with figures are described in detail below.
Drawings
FIG. 1 is a schematic diagram of a touch sensing device according to an embodiment of the invention;
FIGS. 2-4 are schematic diagrams illustrating the output voltage of the amplification circuit, the integrated charge of the background signal, and the integrated charge of the subtracted signal according to embodiments of the present invention;
FIG. 5 is a schematic diagram of the integrated charge of a subtracted signal according to another embodiment of the present invention;
FIG. 6 is a schematic diagram of a touch sensing device according to another embodiment of the invention;
FIG. 7 is a schematic diagram of a capacitor unit according to an embodiment of the invention;
FIG. 8 is a waveform diagram of a control signal of a switch according to an embodiment of the invention;
FIG. 9 is a schematic diagram of a touch sensing device according to another embodiment of the invention;
FIG. 10 is a waveform diagram of a control signal of a switch according to an embodiment of the invention;
FIG. 11 is a schematic diagram of a touch sensing device according to another embodiment of the invention;
FIG. 12 is a waveform diagram of control signals and digital control signals of a switch according to an embodiment of the invention;
fig. 13 is a schematic diagram of an output voltage of an amplifying circuit, an integrated charge of a background signal, and an integrated charge of a subtracted signal according to an embodiment of the invention.
Reference numerals:
102: an amplifying circuit;
104: an analog-to-digital conversion circuit;
106: a processing circuit;
108: a correction circuit;
202. 902: a switching circuit;
204. 904: a capacitor unit;
206. 906: a switching circuit;
1102: a current draw circuit;
s1: touch sensing signals;
SM 1: deducting the signal;
VO, VO ', VO1 ' -VO 4 ': outputting the voltage;
QB, QM 1-QM 5: integrating the charge;
r1: outputting a dynamic range;
r2: a saturation range;
VCM: a reference voltage;
VOL: a critical saturation output voltage;
VBK: correcting the voltage;
q, Δ Q: deducting the electric quantity;
VDDH: an operating voltage;
CT: a touch capacitor;
a1: an amplifier;
CS: sensing a capacitance;
CINT, Clsb: a capacitor;
SW1 to SW12, SW1 'to SWN': a switch;
SC 1-SC 7: a control signal;
SD 1: a digital control signal;
t1: a reset period;
t2: a touch sensing period;
GND: a ground voltage;
and (3) CBK: a variable capacitance;
COD 1-CODN: a digital control code.
Detailed Description
Fig. 1 is a schematic diagram of a touch sensing device according to an embodiment of the invention, and fig. 1 is referred to. The touch sensing device includes an amplifying circuit 102, an analog-to-digital converting circuit 104, a processing circuit 106, and a correcting circuit 108, wherein the analog-to-digital converting circuit 104 is coupled to the amplifying circuit 102 and the processing circuit 106, and the correcting circuit 108 is coupled to an input terminal of the amplifying circuit 102 and the processing circuit 106. The amplifying circuit 102 is configured to receive the touch sensing signal S1 from the output terminal thereof during the touch sensing period, and amplify the touch sensing signal S1. The analog-to-digital conversion circuit 104 is used for converting the touch sensing signal S1 into a digital signal and outputting the digital signal to the processing circuit 106, and the processing circuit 106 can determine the touch position according to the digital signal. In addition, the processing circuit 106 may also control the correction circuit 108 to subtract a signal component of the touch sensing signal S1, for example, a background signal included in the touch sensing signal S1, for a plurality of times during the touch sensing period, so as to increase the signal-to-noise ratio of the signal output to the amplifying circuit 102. For example, fig. 2 and fig. 3 are schematic diagrams of the output voltage VO, the output voltage VO ', the output voltage VO 1', the integrated charge QB of the background signal of the amplifying circuit 102 and the integrated charge QM1 of the subtracted signal SM1 subtracted by the correcting circuit 108 according to the embodiment of the invention. In the embodiment shown in fig. 2, the calibration circuit 108 performs a signal component subtraction on the touch sensing signal S1 once to avoid saturation of the output of the amplifying circuit 102 caused by the background signal, as shown in fig. 2, the amplifying circuit 102 generates the output voltage VO when the signal component subtraction is not performed, and the amplifying circuit 102 generates the output voltage VO 'after the signal component subtraction is performed, obviously, by subtracting the background signal included in the touch sensing signal S1, the output voltage VO' can be effectively maintained within the output dynamic range R1 without falling into the saturation range R2, thereby avoiding saturation of the output of the amplifying circuit 102. The voltage VCM is a reference voltage of the amplifying circuit 102 for signal amplification, and the voltage VOL is a critical saturation output voltage of the amplifying circuit 102.
Although the touch sensing device of the embodiment of fig. 2 can effectively avoid the output saturation of the amplifying circuit 102 in most cases, the output distortion may occur if the instantaneous variation of the touch sensing signal S1 is too large. Therefore, in some embodiments, the output voltage swing of the amplifying circuit 102 can be further reduced by adjusting the number of times the correcting circuit 108 subtracts the background signal. As shown in the embodiment of fig. 3, the subtraction of the background signal is performed in 6 times, wherein the integrated charge QM1 of the subtracted signal SM1 in fig. 3 is the same as the integrated charge QM of the subtracted signal SM1 in fig. 2, but since the subtraction of the background signal is performed in multiple subtractions in the embodiment of fig. 3, the voltage swing of the output voltage VO1 'generated by the amplifying circuit 102 in the embodiment of fig. 3 is smaller than the voltage swing of the output voltage VO' generated by the amplifying circuit 102 in the embodiment of fig. 2.
In addition, since different positions on the touch panel may correspond to different background signals, or different touch panels may have different background signals, if the background signals are subtracted by the same subtraction amount for multiple times, the touch sensing signal S1 generated by the touch panel cannot obtain a desired subtraction effect. To solve this problem, the amount of the background signal subtraction can be varied to ensure that the touch sensing signal S1 falls within the output dynamic range R1. For example, fig. 4 shows the integrated charge QM2 and the integrated charge QM3 of the output voltage VO, the output voltage VO2 ', the output voltage VO 3', the integrated charge QB of the background signal and the subtracted signal SM1 of the correction circuit 108 of the amplifying circuit 102 according to another embodiment of the invention. In the present embodiment, the amplifying circuit 102 generates the output voltage VO2 'when the background signal of the touch sensing signal S1 is subtracted in an equal manner (each time the decrement amount Q is subtracted), and the amplifying circuit 102 generates the output voltage VO 3' when the background signal of the touch sensing signal S1 is subtracted in an equal manner (each time the decrement amount Δ Q is subtracted). As can be seen from fig. 4, the output voltage VO3 'has a smaller swing than the output voltage VO 2', so that the swing of the output voltage of the amplifying circuit 102 can be adjusted according to the characteristics of the touch panel by changing the subtraction amount of the background signal, thereby further preventing the amplifying circuit 102 from being saturated by the output voltage.
It is noted that the manner of changing the amount of the background signal is not limited to the embodiment shown in fig. 4, and the background signal may be subtracted in different manners in other embodiments. For example, fig. 5 is a schematic diagram of the integrated charge QM4 of the subtracted signal SM1 according to another embodiment of the present invention, in which the correction circuit 108 subtracts the background signal in an exponential decreasing manner, which can also achieve the effect of adjusting the swing of the output voltage of the amplifying circuit 102, thereby preventing the amplifying circuit 102 from output voltage saturation.
Fig. 6 is a schematic diagram of a touch sensing device according to another embodiment of the invention, please refer to fig. 6. In the present embodiment, the touch sensing device is configured to receive a touch sensing signal S1 of the capacitive touch panel, wherein the capacitive touch panel may include a touch capacitor CT and a sensing capacitor CS, the touch capacitor CT and the sensing capacitor CS are connected in parallel and are connected in series with the switch SW1 between the operating voltage VDDH and ground, and a common node of the touch capacitor CT, the sensing capacitor CS and the switch SW1 is coupled to the amplifying circuit 102 through the switch SW 2.
In the present embodiment, the amplifying circuit 102 includes an amplifier a1, a capacitor CINT and a switch SW3, wherein a negative input terminal of the amplifier a1 is coupled to the switch SW2, a positive input terminal thereof receives the reference voltage VCM, and the capacitor CINT and the switch SW3 are connected in parallel between the negative input terminal and the output terminal of the amplifier a 1. In addition, the correction circuit 108 of the present embodiment includes a switching circuit 202, a capacitance unit 204, and a switching circuit 206. The switching circuit 202 is coupled between the capacitor unit 204, the calibration voltage VBK and the reference voltage VCM, and the switching circuit 206 is coupled between the capacitor unit 204, the negative input terminal of the amplifier a1 and the ground voltage GND. The switching circuit 202 can be implemented by the switch SW4 and the switch SW5 as shown in fig. 6, and the switching circuit 206 can be implemented by the switch SW6 and the switch SW7, but not limited thereto. The capacitor unit 204 may be a variable capacitor CBK, which may include a plurality of switches SW1 'to SWN' and a plurality of capacitors Clsb, each capacitor Clsb being connected in series with its corresponding switch between the switching circuit 202 and the switching circuit 206, as shown in fig. 7. The switches SW1 '-SWN' can be controlled by the control signal from the processing circuit 106 to change their conducting states, thereby changing the capacitance of the capacitor unit 204.
Fig. 8 is a schematic waveform diagram of control signals of the switches SW 1-SW 7 according to an embodiment of the invention, please refer to fig. 6 and fig. 8 at the same time. In the reset period T1, the switches SW1 and SW3 are turned on by the control signal SC1, and the switch SW2 is turned off by the control signal SC2, so as to reset the voltages on the touch capacitor CT, the sensing capacitor CS and the capacitor CINT. During the touch sensing period T2, the switches SW1 and SW3 are turned off by the control signal SC1, and the switch SW2 is turned on by the control signal SC 2. In addition, during the touch sensing period T2, the switches SW4 to SW7 are controlled by the control signal SC3 and the control signal SC4 to be alternately turned on and off, wherein the switches SW5 and SW6 are turned off when the switches SW4 and SW7 are turned on, and the switches SW5 and SW6 are turned on when the switches SW4 and SW7 are turned off. The number of times the background signal is subtracted from the touch sensing signal S1 by the calibration circuit 108 can be adjusted by controlling the number of times the switches SW 4-SW 7 are turned on and off, and the capacitance of the capacitor unit 204 can be adjusted to control the amount of subtraction of the background signal each time, for example, the amount of subtraction of the signal component of the touch sensing signal S1 is decreased in an equal difference manner or decreased in an exponential manner, so as to adjust the swing of the output voltage of the amplification circuit 102 and avoid the saturation of the output voltage of the amplification circuit 102. The more the background signal subtraction is performed, the smaller the capacitance value required by the capacitor unit 204 is, so that the circuit area required by implementing the capacitor unit 204 can be reduced by increasing the background signal subtraction, thereby reducing the manufacturing cost of the touch sensing device.
Fig. 9 is a schematic view of a touch sensing device according to another embodiment of the invention, please refer to fig. 9. The difference between the touch sensing device of the present embodiment and the touch sensing device of the embodiment in fig. 6 is that the calibration circuit 108 of the touch sensing device of the present embodiment further includes a switching circuit 902, a capacitor unit 904, and a switching circuit 906. The switching circuit 902 is coupled between the capacitor 904, the calibration voltage VBK and the reference voltage VCM, and the switching circuit 906 is coupled between the capacitor 904, the negative input terminal of the amplifier a1 and the ground voltage GND. The switch circuit 902 can be implemented by the switch SW8 and the switch SW9 as shown in fig. 9, and the switch circuit 906 can be implemented by the switch SW10 and the switch S11, but not limited thereto.
Fig. 10 is a schematic waveform diagram of control signals of the switches SW 1-SW 11 according to an embodiment of the invention, please refer to fig. 9 and fig. 10 at the same time. Similar to the embodiment of fig. 6, during the touch sensing period T2, the switches SW4 to SW11 are controlled by the control signals SC3 to SC6 to be alternately turned on and off, wherein the phases of the control signals SC5 and SC6 respectively lag behind the phases of the control signals SC3 and SC4 by a half cycle. The switches SW5 and SW6 are turned off when the switches SW4 and SW7 are turned on, the switches SW5 and SW6 are turned on when the switches SW4 and SW7 are turned off, the switches SW9 and SW10 are turned off when the switches SW8 and SW11 are turned on, and the switches SW9 and SW10 are turned on when the switches SW8 and SW11 are turned off. The number of times the calibration circuit 108 subtracts the background signal from the touch sensing signal S1 can be adjusted by controlling the number of times the switches SW 4-SW 11 are turned on and off, and the amount of subtraction of the background signal can be controlled by adjusting the capacitance values of the capacitor 204 and the capacitor 904. In addition, other circuit components of the present embodiment are the same as those of the embodiment of fig. 6, and therefore are not described herein again. It should be noted that, in the present embodiment, the calibration circuit 108 is implemented by two sets of circuits composed of the capacitor units and the switching circuits, but not limited thereto, and in other embodiments, the calibration circuit 108 may also be implemented by more sets of circuits composed of the capacitor units and the switching circuits.
Fig. 11 is a schematic view of a touch sensing device according to another embodiment of the invention, please refer to fig. 11. The touch sensing device of the present embodiment is different from the touch sensing device of the embodiment shown in fig. 6 in that the calibration circuit 108 of the touch sensing device of the present embodiment is implemented by a current extraction circuit 1102 and a switch SW12, and the current extraction circuit 1102 can be, for example, a variable current source controlled by the processing circuit 106 to change the current extracted from the negative input terminal of the amplifier a1 so as to multiply reduce the signal component of the touch sensing signal S1.
Further, the current draw circuit 1102 may be implemented, for example, as a current array, which may draw the current of the negative input terminal of the amplifying circuit 102 multiple times according to the digital control signal SD1 from the processing circuit 106 to adjust the amount of the signal component of the touch sensing signal S1 to be clipped. Fig. 12 is a schematic waveform diagram of control signals of the switches SW 1-SW 3 and the digital control signal SD1 according to an embodiment of the invention, please refer to fig. 11 and fig. 12 simultaneously. As shown in fig. 12, during the touch sensing period T2, the switch SW12 is controlled by the control signal SC7 to be turned on, and during the period that the switch SW12 is turned on, the current draw circuit 1102 can receive the digital control signal SD1 from the processing circuit 106 through the switch SW12, so as to change the current drawn from the negative input terminal of the amplifier a 1. As shown in fig. 12, during the period when the control signal SC7 is converted to the high voltage level, the processing circuit 106 may output the digital control signal SD1 having a plurality of digital control codes COD 1-CODN to the current extraction circuit 1102, so as to extract the current at the negative input terminal of the amplifier a1 for a plurality of times during the touch sensing period, and further subtract the signal component of the touch sensing signal S1 for a plurality of times. Fig. 13 is a schematic diagram of the output voltage VO of the amplifying circuit 102, the output voltage VO 4', the integrated charge QB of the background signal, and the integrated charge QM5 of the subtracted signal SM1 subtracted by the correcting circuit 108 according to an embodiment of the invention. Similarly, the signal component of the touch sensing signal S1 can be subtracted by an equal amount or an exponential subtraction, as shown in fig. 13, the current draw circuit 1102 can draw the current of the negative input terminal of the amplifier a1 by an exponential subtraction according to the digital control code to adjust the swing of the output voltage of the amplifying circuit 102, thereby preventing the amplifying circuit 102 from being saturated by the output voltage.
In summary, in the touch sensing device according to the embodiments of the invention, the calibration circuit subtracts the signal component of the touch sensing signal received by the amplification circuit for multiple times during the touch sensing period, so as to effectively eliminate the background signal in the detected touch sensing signal at different positions of the same touch panel or the background signal in the detected touch sensing signal of different touch panels, thereby avoiding saturation of the output of the amplification circuit and greatly improving the use quality of the touch sensing device.
Although the present invention has been described with reference to the above embodiments, it should be understood that the invention is not limited to the embodiments disclosed, but rather, may be embodied in many other forms without departing from the spirit or scope of the present invention.
Claims (4)
1. A touch sensing device, comprising:
the amplifying circuit receives a touch sensing signal from an input end thereof and amplifies the touch sensing signal during touch sensing;
an analog-to-digital conversion circuit coupled to the amplifying circuit for converting the touch sensing signal into a digital signal;
the processing circuit is coupled with the analog-digital conversion circuit and judges the touch position according to the digital signal;
a capacitor unit;
a first switching circuit coupled between the capacitor unit, the calibration voltage and a reference voltage; and
a second switching circuit, coupled between the capacitor unit, the input terminal of the amplifier circuit, and a ground voltage, wherein during the touch sensing period, the first switching circuit and the second switching circuit are controlled by a processing circuit to switch between a first state and a second state to reduce the signal component of the touch sensing signal for multiple times, in the first state, the first switching circuit turns on the calibration voltage and turns off the reference voltage, the second switching circuit turns on the ground voltage and turns off the input terminal of the amplifier circuit, the first switching circuit and the second switching circuit couple the capacitor unit between the calibration voltage and the ground voltage, in the second state, the first switching circuit turns on the reference voltage and turns off the calibration voltage, and the second switching circuit turns on the input terminal of the amplifier circuit and turns off the ground voltage, the first switching circuit and the second switching circuit couple the capacitor unit between the input terminal of the amplifying circuit and the reference voltage.
2. The touch sensing device of claim 1, wherein the capacitive unit is a variable capacitor, and the processing circuit changes a capacitance value of the capacitive unit to change a decrement of a signal component of the touch sensing signal.
3. The touch sensing device of claim 2, wherein the amount of subtraction of the signal component of the touch sensing signal is decreased in an arithmetic manner or an exponential manner.
4. The touch sensing device of claim 1, wherein the amplification circuit comprises:
a positive input end and a negative input end of the amplifier respectively receive the reference voltage and the touch sensing signal, and an output end of the amplifier is coupled to the analog-to-digital conversion circuit;
the second capacitor unit is coupled between the negative input end and the output end of the amplifier; and
and the switch is coupled between the negative input end and the output end of the amplifier, and enables the negative input end and the output end of the amplifier to be in short circuit in the reset period.
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| TW105130485 | 2016-09-21 | ||
| TW105130485A TWI599933B (en) | 2016-09-21 | 2016-09-21 | Touch sensing apparatus |
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| CN107844222B true CN107844222B (en) | 2021-01-26 |
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| CN111258442A (en) * | 2018-12-03 | 2020-06-09 | 陕西坤同半导体科技有限公司 | Touch sensing circuit, touch display panel, display device and electronic equipment |
| CN111353421A (en) * | 2019-04-19 | 2020-06-30 | 神盾股份有限公司 | Optical fingerprint sensing device |
| TWI693545B (en) * | 2019-04-26 | 2020-05-11 | 大陸商北京集創北方科技股份有限公司 | Touch chip, touch display device and information processing device |
| WO2021036306A1 (en) * | 2019-08-27 | 2021-03-04 | 神盾股份有限公司 | Capacitance sensing device |
| US20230152916A1 (en) * | 2020-04-29 | 2023-05-18 | Egis Technology Inc. | Electronic device having fingerprint sensing function |
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Also Published As
| Publication number | Publication date |
|---|---|
| TWI599933B (en) | 2017-09-21 |
| CN107844222A (en) | 2018-03-27 |
| TW201812543A (en) | 2018-04-01 |
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