CN102200869B - Capacitance type touch control device and sensing device thereof - Google Patents

Capacitance type touch control device and sensing device thereof Download PDF

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CN102200869B
CN102200869B CN 201010143201 CN201010143201A CN102200869B CN 102200869 B CN102200869 B CN 102200869B CN 201010143201 CN201010143201 CN 201010143201 CN 201010143201 A CN201010143201 A CN 201010143201A CN 102200869 B CN102200869 B CN 102200869B
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switch
capacitance
module
capacitive touch
voltage
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CN102200869A (en
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陈议诚
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Holtek Semiconductor Inc
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Holtek Semiconductor Inc
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Abstract

The invention relates to a capacitance type touch control device and a sensing device thereof. The sensing device comprises a reference capacitance module, a switching module, an integrating circuit, and a control circuit, wherein the switching module is used for receiving control signals, a first reference voltage and a second reference voltage and enabling the reference capacitance module and a capacitance type touch pad to be respectively coupled with the first reference voltage and the second reference voltage according to the control signals, or enabling the reference capacitance module to be coupled to a sensing capacitor on the capacitance type touch pad. The integrating circuit is used for receiving a regulation voltage and carrying out integration on the charge difference of electric charge quantity stored by the reference capacitance module and the sensing capacitor so as to obtain integral results. When the capacitance type touch pad of the control circuit is not touched, the regulation voltage is regulated according to a voltage regulation signal generated by the integral result. According to the capacitance type touch control device and the sensing device thereof, equivalent capacitance errors generated by circuit components and wiring in the touch control device do not need to be taken into account, and therefore capacitance changes on the capacitance type touch pad can be accurately detected.

Description

Capacitive touch device and sensing apparatus thereof
Technical field
The present invention relates to a kind of capacitive touch device, and be particularly related to a kind of sensing apparatus of capacitance variations of capacitive touch device.
Background technology
In consumption electronic products today of universalness day by day, for humanized man-machine interface is provided, necessity that Trackpad has become multiple electronic product is equipped with.And in technical field now, Trackpad can generally be divided into capacitive touch control plate and resistor type touch control plate again.
Capacitive touch control plate is mainly to carry out the detection of touch points according to the capacitance variations that is produced when Trackpad is touched by the user.Wherein, a kind of metering circuit of so-called charge transfer capacitance (chargetransfer capacitance measurement circuit) often is used to the detection of the touch points of carrying out capacitive touch control plate.Please refer to Fig. 1, Fig. 1 illustrates the sensing apparatus 100 of known capacitive touch device.In the operation of sensing apparatus 100, at first actuating switch S3 so that the electric charge that remains on capacitor C c can be removed completely.Then actuating switch S1, and make sense capacitance Cs on Trackpad can be charged to the voltage level of reference voltage VDD.
After sense capacitance Cs completes charging, close swap switch S1, S3 and actuating switch S2, so that the electric charge that is stored on sense capacitance Cs partly transfers on capacitor C c, until this electric charge transfer action is completed (when the voltage Vint that sense capacitance Cs and Cc couple end stablizes).And then conducting and disconnect S1 (opening circuit simultaneously and actuating switch S2) by repeating, make voltage Vint surpass reference voltage Vref and make the output generation transition of comparator C MP1.The transition situation of 110 count comparator CMP1 of counter output, then the time of learning the transition of comparator C MP1 output by control circuit 120, and and then know the capacitance variations of sense capacitance Cs, advance to detect the state of touching.
Only have 1% ~ 5% because the capacitance variations of sense capacitance Cs is rough, so the variation of 110 obtainable count values of counter is also not too large, relative, the susceptibility of sensing apparatus 100 just can not be too high.And for the variation that makes count value can become greatly, known technology is also by improving the capacitance of capacitor C c.But but this practice has increased the cost of circuit.
Summary of the invention
The invention provides a kind of sensing apparatus, in order to the capacitance variations of Detection capacitance formula Trackpad.
The invention provides a kind of capacitive touch device, detect accurately the capacitance variations of its capacitive touch control plate.
The present invention proposes a kind of sensing apparatus, in order to the capacitance variations of Detection capacitance formula Trackpad.Sensing apparatus comprises reference capacitance module, switch module, integrating circuit and control circuit.Switch module couples reference capacitance module and capacitive touch control plate, reception control signal, the first reference voltage and the second reference voltage, and make reference capacitance module and capacitive touch control plate couple respectively first and second reference voltage or make the reference capacitance module be coupled to capacitive touch control plate according to control signal.Integrating circuit has first and second input end, and its first input end couples jointly coupling a little of reference capacitance module and capacitive touch control plate, and its second input end receives adjusts voltage.Integrating circuit is adjusting voltage under benchmark, carries out integration for the electric charge difference of reference capacitance module and the stored quantity of electric charge of capacitive touch control plate, and so as to obtaining integral result.Control circuit couples integrating circuit, and when capacitive touch control plate was not touched, control circuit produced voltage adjustment signal adjustment voltage according to integral result.
In one embodiment of this invention, above-mentioned reference capacitance module comprises a plurality of electric capacity and a plurality of switch element.One end of all electric capacity couples switch module jointly, and each switch element is serially connected with respectively between the second reference voltage and each electric capacity.The control end of all switch elements couples control circuit.
In one embodiment of this invention, above-mentioned control circuit more is included in capacitive touch control plate when not touched, the conducting of controlling each switch element according to integral result whether, to adjust the capacitance of reference capacitance module.
In one embodiment of this invention, above-mentioned sensing apparatus more comprises analog-digital converter.Analog-digital converter is serially connected in coupling between the path of integrating circuit and control circuit.Analog-digital converter receives integral result and integral result is converted to digital format by analog format.
In one embodiment of this invention, above-mentioned sensing apparatus more comprises digital analog converter, between serial connection integrating circuit and control circuit.The voltage adjustment signal that the digital analog converter receiver voltage is adjusted signal and converting digital form is analog format.
In one embodiment of this invention, above-mentioned switch module comprises the first switch, second switch, the 3rd switch and the 4th switch.The first switch series is connected between reference capacitance module and integrating circuit.Second switch is serially connected between reference capacitance module and the first reference voltage.The 3rd switch series is connected between capacitive touch control plate and integrating circuit.The 4th switch series is connected between capacitive touch control plate and the second reference voltage.Wherein, first, second, third and fourth switch all is controlled by control signal, and the turned on or off of first and third switch and second, four switches are opposite, and the first switch is identical with the turned on or off of the 3rd switch, and second switch is identical with the turned on or off of the 4th switch.
In one embodiment of this invention, above-mentioned integrating circuit comprises operational amplifier, integrating capacitor and first and second and third integral switch.The first input end of operational amplifier couples the first input end of integrating circuit, and its second input end couples the second input end of integrating circuit, and its output terminal produces integral result.One end of integrating capacitor couples the first input end of operational amplifier, and an end of first integral switch and operational amplifier and integrating capacitor couple jointly, and its other end couples the output terminal of operational amplifier.The second integral switch series is connected between the output terminal of the other end of integrating capacitor and operational amplifier.One termination of third integral switch is received the integration starting potential, and its other end and integrating capacitor and second integral switch couple jointly.
In one embodiment of this invention, above-mentioned second integral switch is opposite with the conducting closed condition of third integral switch, and the conducting closed condition of first and third integral restrictor is identical.
The present invention proposes a kind of capacitive touch device, comprises capacitive touch control plate and sensing apparatus.Capacitive touch control plate has a plurality of sense capacitance.Sensing apparatus coupling capacitance formula Trackpad is in order to detect the capacitance variations of each sense capacitance.Sensing apparatus comprises reference capacitance module, switch module, integrating circuit and control circuit.Switch module couples reference capacitance module and capacitive touch control plate.Switch module reception control signal, the first reference voltage and the second reference voltage, and make reference capacitance module and sense capacitance couple respectively first and second reference voltage or make the reference capacitance module be coupled to one of them of capacitive touch control plate according to control signal.Integrating circuit has first and second input end, and its first input end couples one of them jointly couple a little of reference capacitance module and sense capacitance.Its second input end receives adjusts voltage, and carries out integration for the electric charge difference of one of them stored quantity of electric charge of reference capacitance module and sense capacitance, and so as to obtaining integral result.Control circuit couples integrating circuit, when capacitive touch control plate is not touched, produces voltage adjustment signal according to integral result.
Based on above-mentioned, the present invention is by when capacitive touch control plate is not touched, the integral result that detects integrating circuit output is known the difference of the equivalent capacity between integrating circuit two input ends, and changes adjustment voltage to reduce the difference of above-mentioned equivalent capacity according to integral result.Advance so that capacitive touch control plate is being touched when detecting, can not need to consider the equivalent capacity error that circuit component in contactor control device and wiring produce, detect more accurately the capacitance variations on capacitive touch control plate.
For above-mentioned feature and advantage of the present invention can be become apparent, embodiment cited below particularly, and coordinate accompanying drawing to be described in detail below.
Description of drawings
Fig. 1 illustrates the sensing apparatus 100 of known capacitive touch device.
Fig. 2 is the schematic diagram that the sensing apparatus 200 of one embodiment of the invention is shown.
Fig. 3 is the schematic diagram that the sensing apparatus 300 of another embodiment of the present invention is shown.
Fig. 4 is the movement oscillogram that the sensing apparatus 300 of the embodiment of the present invention is shown.
Fig. 5 is the embodiment that the reference capacitance module 310 of the embodiment of the present invention is shown.
Fig. 6 is the schematic diagram that the capacitive touch device 600 of one embodiment of the invention is shown.
Fig. 7 illustrates the movement oscillogram of capacitive touch device 600.
Description of reference numerals in above-mentioned accompanying drawing is as follows:
100,200,300,601: sensing apparatus
110: counter
210,310,610: the reference capacitance module
220,320,620: switch module
230,330,630: integrating circuit
240,120,340,640: control circuit
350,650: analog-digital converter
360,660: digital analog converter
600: capacitive touch device
Vzr: integration starting potential
OPAMP1: operational amplifier
S1 ~ S3, Sp0 ~ Sp4, Sn0 ~ Sn4, Sa, Sb, Sa ': switch
SW1 ~ SWM: switch element
Vint: voltage
CMP1: comparer
TPAD: capacitive touch control plate
TI1, TI2, TC: end points
Vcm1, Vcm1_1: adjust voltage
CTRL: control signal
VDD, GND: reference voltage
OUT, OUT_1: integral result
Cp1 ~ Cp4, Cref, Cc, Cs, Cint, C1 ~ CM: electric capacity
T1 ~ T2: time cycle
Embodiment
At first please refer to Fig. 2, Fig. 2 is the schematic diagram that the sensing apparatus 200 of one embodiment of the invention is shown.Sensing apparatus 200 wherein is in order to the capacitance variations of the sense capacitance Cp on Detection capacitance formula Trackpad TPAD.Sensing apparatus 200 comprises reference capacitance module 210, switch module 220, integrating circuit 230 and control circuit 240.Switch module 220 couples reference capacitance module 210 and this sense capacitance Cp.Integrating circuit 230 has first and second input end TI1, TI2, and what its first input end TI1 coupled reference capacitance module 210 and this sense capacitance Cp couples a TC jointly, and its second input end TI2 receives and adjusts voltage Vcm1.240 of control circuits couple integrating circuit 230 and reference capacitance module 210 and the adjustment signal of adjusting voltage Vcm1 to integrating circuit 230 and being used for adjusting the capacitance of reference capacitance module 210 are provided.
Switch module 220 reception control signal CTRL, the first reference voltage VDD and the second reference voltage GND.Switch module 220 also makes reference capacitance module 210 and sense capacitance Cp couple respectively first and second reference voltage VDD, GND or makes reference capacitance module 210 and sense capacitance Cp together is coupled to integrator input end TC according to control signal CTRL.In simple terms, in the present embodiment, switch module 220 can make according to the state (for example control signal CTRL presents logic high) of control signal CTRL reference capacitance module 210 be couple to the first higher reference voltage VDD of voltage level charging, and makes simultaneously sense capacitance Cp be couple to the second lower reference voltage GND of voltage level to discharge.Opposite, if when control signal CTRL presents logic low, 220 of switch modules can make reference capacitance module 210 and sense capacitance Cp jointly be coupled to and couple a TC, shift with the electric charge that carries out between reference capacitance module 210 and sense capacitance Cp.
Note that at this above-mentioned switch module 220 changes mode example just only of the coupling access status of reference capacitance module 210 and sense capacitance Cp according to the logic high-low level of control signal CTRL, not in order to limit the present invention.In addition, it is reference voltage GND that above-mentioned embodiment also can change the first reference voltage, and to change the second reference voltage be reference voltage VDD.And be couple to the first reference voltage GND with reference to capacitance module 210 and discharge, and sense capacitance Cp is couple to the second reference voltage VDD, can implement the present embodiment too.
230, integrating circuit is used in for the electric charge difference of reference capacitance module 210 and the stored quantity of electric charge of inductance capacitance Cp and carries out integration, and so as to obtaining integral result OUT.Furthermore, reference capacitance module 210 and sense capacitance Cp complete respectively by reference voltage VDD and GND discharge and recharge action after, and be coupled in when coupling end TC, control circuit 240 provides adjusts voltage Vcm1 to integrating circuit 230, and so as to the difference of the quantity of electric charge stored in computing reference capacitance module 210 and sense capacitance Cp.In simple terms, the stored quantity of electric charge of reference capacitance module 210 equals Cref (VDD-Vcm1), in sense capacitance Cp, the stored quantity of electric charge equals Cp (Vcm1-GND), and the electric charge difference is Cref (VDD-Vcm1)-Cp* (Vcm1-GND).
Note that impact due to the difference of the circuit component in sensing apparatus 200 and configuration therebetween at this, the equivalent capacity that two input ends of integrating circuit 230 are seen can't be expected.Under the adjustment action of the control circuit 240 of the present embodiment, the error of the capacitance variations detection of the sense capacitance Cp that these phenomenons that can not expect may cause can be eliminated.
Completed the adjustment work of Vcm1 at control circuit 240 after, sensing apparatus 200 just can finish the action of adjustment, and the actual touching state of knowing capacitive touch control plate TPAD according to integral result OUT.And because integrating circuit 230 only carries out integration for the variation of the touched sense capacitance Cp that produces of capacitive touch control plate TPAD, the resolution of therefore touching state-detection for integral result OUT can effectively increase.
Then please refer to Fig. 3, Fig. 3 is the schematic diagram that the sensing apparatus 300 of another embodiment of the present invention is shown.Sensing apparatus 300 comprises reference capacitance module 310, switch module 320, integrating circuit 330, control circuit 340, analog-digital converter 350 and digital analog converter 360 in order to the capacitance variations of sense capacitance Cp in Detection capacitance formula Trackpad TPAD.Wherein, switch module 320 comprises switch S p0, Sn0, Sp1 and Sn1.Switch S p0 is serially connected in 330, reference capacitance module 310 and integrating circuit, and switch S n0 is serially connected between reference capacitance module 310 and the first reference voltage VDD.Switch S p1 is serially connected in 330, sense capacitance Cp and integrating circuit, and switch S n1 is serially connected between capacitive touch control plate TPAD and the second reference voltage GND.
Note that the conducting of switch S p0 and switch S n0 or the opposite states that opens circuit, the conducting of switch S p1 and switch S n1 or the opposite states that opens circuit.And the conducting of switch S p1 and switch S p0 or the state that opens circuit are identical, and the conducting of switch S n1 and switch S n0 or the state that opens circuit identical.
Integrating circuit 330 comprises operational amplifier OPAMP1, integrating capacitor Cint and integral restrictor Sa, Sb, Sa '.The first input end of operational amplifier OPAMP1 couples the first input end of integrating circuit 330, and its second input end couples the second input end of integrating circuit 330, and its output terminal produces integral result OUT_1.The end of integrating capacitor Cint couples the first input end of operational amplifier OPAMP1, and its other end couples integral restrictor Sa and Sb.The other end of integral restrictor Sa receives integration starting potential Vzr, and the other end of integral restrictor Sb couples the output terminal of operational amplifier OPAMP1.In addition, integral restrictor Sa ' is connected across between the first input end and output terminal of operational amplifier OPAMP1.
Aspect the action details of sensing apparatus 300, please be simultaneously with reference to Fig. 3 and Fig. 4, wherein Fig. 4 is the movement oscillogram that the sensing apparatus 300 of the embodiment of the present invention is shown.At first, sensing apparatus 300 need carry out initialized action, namely integral restrictor Sa, Sa ' are switched on (Fig. 4 illustrates Sa, Sa ' and is switched on for high level represents integral restrictor Sa, Sa '), integral restrictor Sb is opened circuit (cut-out), makes can the reset action of (reset) of integrating circuit 330.After the replacement action of completing integrating circuit 330, integral restrictor Sa, Sa ' are opened circuit, and integral restrictor Sb is switched on.The action (switch S n0, Sn1 respective opposite repeat sequentially to open circuit and conducting in switch S p0, Sp1) that switch S p0, Sp1 repeat sequentially conducting according to control signal CTRL and open circuit, make electric charge difference stored in sense capacitance Cp and reference capacitance module 310, conversion is stored in integrating capacitor Cint.Switch S p0, Sp1 carry out the conducting of N time (N is positive integer) and the action of opening circuit after, utilize sampled signal ADCS to come shown in the following mathematical expression of integral result OUT_1 (1) that the Sampling Integral circuit produces:
OUT _ 1 = Vzr + [ Cp · Vcm 1 - Cref ] · ( VDD - Vcm 1 ) Cint × N - - - ( 1 )
Suppose and adjust voltage Vcm1=VDD/2+dV, C=Cp-Cn, and dC=Cref-Cn, wherein Cn is initial when not touched () capacitance of capacitive touch control plate TPAD.Mathematical expression (1) can be rewritten as mathematical expression as follows (2):
OUT _ 1 = Vzr + [ ΔC Cint · VDD 2 + 2 Cn · dV - dC · VDD 2 Vint ] × N - - - ( 2 )
Wherein
Figure GDA00002457018100073
For being used for Detection capacitance formula Trackpad TPAD by the Effective Numerical of after touch capacitance variations, and The value that is downgraded for hope (being adjusted into 0 for best).
Therefore, dV can be set and equal (dC/4Cn) * VDD, and control circuit 340 can be obtained the magnitude of voltage of best adjustment voltage Vcm1 according to this.In addition, also can be known by mathematical expression (2), control circuit 340 also can be adjusted dC by the capacitance Cref that adjusts reference capacitance module 310, reaches to make 2 Cn · dV - dC · VDD 2 Drop to minimum demand.
And after the adjustment suitable through control circuit 340, integral result OUT_1 can further be rewritten into down the mathematical expression (3) of showing:
OUT _ 1 = Vzr + [ ΔC Cint · VDD 2 ] × N - - - ( 3 )
Please again with reference to Fig. 3, in the present embodiment, sensing apparatus 300 more integrating circuit 330 and 340 construction of control circuit analog-digital converter 350 and digital analog converter 360.This framework is that to be applied in control circuit 340 be a control circuit of processing according to digital signal.Therefore, the integral result OUT_1 of the simulation that produces of integrating circuit 330 need produce through the format conversion of analog-to-digital the integral result OUT of numeral to transfer to control circuit 340.Identical reason, control circuit 340 transmit digital formats adjustment voltage Vcm1_1 and by digital analog converter 360 carry out format conversion that digital revolving die intends with the adjustment voltage Vcm1 that produces simulation to offer integrating circuit 330.
Below please refer to Fig. 5, Fig. 5 illustrates an embodiment of the reference capacitance module 310 of the embodiment of the present invention.Wherein, reference capacitance module 310 comprises that capacitor C 1 ~ CM and switch element SW1 ~ SWM are total to M electric capacity and switch element, and M wherein is positive integer.The end of capacitor C 1 ~ CM is coupled to switch module 320 jointly, and switch element SW1 ~ SWM is serially connected in respectively between the other end and the second reference voltage GND of capacitor C 1 ~ CM.Switch element SW1 ~ SWM all is controlled by the action that control circuit 340 carries out conducting or cuts out.At this, capacitor C 1 ~ CM can utilize the electric capacity of a plurality of different capacitances to come construction, and when control circuit 340 will be selected the capacitance of one of them electric capacity (for example capacitor C 3), a corresponding actuating switch cell S W3 got final product.Or capacitor C 1 ~ CM also can come construction with the identical electric capacity of capacitance, and the number by actuating switch cell S W1 ~ SWM, and capacitance module 310 capacitance that provides is provided.
Please refer to Fig. 6, Fig. 6 is the schematic diagram that the capacitive touch device 600 of one embodiment of the invention is shown.Capacitive touch device 600 comprises by the capacitive touch control plate TPAD with a plurality of sense capacitance Cp1 ~ Cpx and sensing apparatus 601.601 of sensing apparatus comprise reference capacitance module 610, switch module 620, integrating circuit 630, control circuit 640, analog-digital converter 650 and digital analog converter 660.The corresponding sense capacitance Cp1 of switch module 620 wherein ~ Cpx and reference capacitance module 610 deploy switch Sp0 ~ Spx and Sn0 ~ Snx.Aspect the action of capacitive touch device 600, please refer to Fig. 7, Fig. 7 is the movement oscillogram that capacitive touch device 600 is shown.Wherein, 1 of period of time T, sensing apparatus 601 carries out the detection of capacitance variations for sense capacitance Cp1,2 of period of time T, sensing apparatus 601 carries out the detection of capacitance variations for sense capacitance Cp2, and in next or a plurality of time cycles, sequentially different capacitive touch control plates is carried out the detection (for example illustrated in fig. 7 carry out respectively the detection of capacitance variations for sense capacitance Cp3, Cp4 in period of time T 3 and T4) of capacitance variations.
It is worth mentioning that, the initialized action of integrating circuit 630 must be moved during each week, therefore integral restrictor Sa, Sa ' and Sb be when each cycle initial, all can carry out the required mutual conducting of the initialization of integrating circuit 630 and the action of opening circuit.
In sum, the present invention detects between reference capacitance module and sense capacitance by when capacitive touch control plate is not touched, is under the condition of benchmark adjusting voltage, the electric charge difference adjustment voltage that produces.When making capacitive touch control plate touched, the detected integral result of sensing apparatus can be simple only presents proportionate relationship with the capacitance variations of capacitive touch control plate.Except the accuracy of the testing result that promotes sensing apparatus, and in the situation that do not need significantly to strengthen the capacitance of reference capacitance module, improve the resolution of the touching state judgement of capacitive touch control plate, effectively put forward the usefulness of capacitive touch crash device.
Although the present invention discloses as above with embodiment; yet it is not to limit the present invention; those of ordinary skill in technical field under any; without departing from the spirit and scope of the present invention; when can do a little change and retouching, therefore protection scope of the present invention is as the criterion when looking appended the scope that claim defines.

Claims (10)

1. sensing apparatus in order to detect the capacitance variations of a capacitive touch control plate, comprising:
One reference capacitance module;
One switch module, couple this reference capacitance module and this capacitive touch control plate, receive a control signal, one first reference voltage and one second reference voltage, make this reference capacitance module and this capacitive touch control plate couple respectively this first and second reference voltage or make this reference capacitance module be coupled to this capacitive touch control plate according to this control signal;
One integrating circuit, has first and second input end, its first input end couples jointly coupling a little of this reference capacitance module and this capacitive touch control plate, its second input end receives one and adjusts voltage, take this adjustment voltage under benchmark, an electric charge difference for this reference capacitance module and the stored quantity of electric charge of this capacitive touch control plate is carried out integration, and so as to obtaining an integral result; And
One control circuit couples this integrating circuit, when this capacitive touch control plate is not touched, produces a voltage adjustment signal according to this integral result and adjusts this adjustment voltage.
2. sensing apparatus as claimed in claim 1, wherein this reference capacitance module comprises:
A plurality of electric capacity, an end of described a plurality of electric capacity couples this switch module jointly; And
A plurality of switch elements, each described switch element are serially connected with respectively between this second reference voltage and each described electric capacity, and the control end of described a plurality of switch elements couples this control circuit.
3. sensing apparatus as claimed in claim 2, wherein this control circuit also is included in this capacitive touch control plate when not touched, the conducting of controlling each described switch element according to this integral result whether, to adjust the capacitance of this reference capacitance module.
4. sensing apparatus as claimed in claim 1, wherein this sensing apparatus also comprises:
One analog-digital converter is serially connected in coupling between the path of this integrating circuit and this control circuit, receives this integral result and this integral result is converted to digital format by analog format.
5. sensing apparatus as claimed in claim 1, wherein this sensing apparatus also comprises:
One digital analog converter is connected in series between this integrating circuit and this control circuit, and this voltage adjustment signal that receives this voltage adjustment signal and converting digital form is analog format.
6. sensing apparatus as claimed in claim 1, wherein this switch module comprises:
One first switch is serially connected between this reference capacitance module and this integrating circuit;
One second switch is serially connected between this reference capacitance module and this first reference voltage;
One the 3rd switch is serially connected between this capacitive touch control plate and this integrating circuit; And
One the 4th switch is serially connected between this capacitive touch control plate and this second reference voltage,
Wherein, this first, second, third and fourth switch all is controlled by this control signal, and this first and third switch is opposite with the turned on or off of these second, four switches, this first switch is identical with the turned on or off of the 3rd switch, and this second switch is identical with the turned on or off of the 4th switch.
7. sensing apparatus as claimed in claim 1, wherein this integrating circuit comprises:
One operational amplifier, its first input end couples the first input end of this integrating circuit, and its second input end couples the second input end of this integrating circuit, and its output terminal produces this integral result;
One integrating capacitor, the one end couples the first input end of this operational amplifier;
One first integral switch, one end and this operational amplifier and this integrating capacitor couple jointly, and its other end couples the output terminal of this operational amplifier;
One second integral switch is serially connected between the output terminal of the other end of this integrating capacitor and this operational amplifier; And
One third integral switch, the one termination is received an integration starting potential, and its other end and this integrating capacitor and this second integral switch couple jointly.
8. sensing apparatus as claimed in claim 7, wherein this second integral switch is opposite with the conducting closed condition of this third integral switch, and the conducting closed condition of this first and third integral restrictor is identical.
9. capacitive touch device comprises:
One capacitive touch control plate has a plurality of sense capacitance; And
One sensing apparatus couples this capacitive touch control plate, and detects respectively the capacitance variations of each described sense capacitance of this capacitive touch control plate, comprising:
One reference capacitance module;
One switch module, couple this reference capacitance module and described a plurality of sense capacitance, receive a control signal, one first reference voltage and one second reference voltage, make this reference capacitance module and described a plurality of sense capacitance couple respectively this first and second reference voltage or make this reference capacitance module be coupled to one of them of described a plurality of sense capacitance according to this control signal;
One integrating circuit, has first and second input end, its first input end couples one of them jointly couple a little of this reference capacitance module and described a plurality of sense capacitance, its second input end receives one and adjusts voltage, an electric charge difference for one of them stored quantities of electric charge of this reference capacitance module and described a plurality of sense capacitance is carried out integration, and so as to obtaining an integral result; And
One control circuit couples this integrating circuit, when described capacitive touch control plate is not touched, produces a voltage adjustment signal according to this integral result and adjusts this adjustment voltage.
10. capacitive touch device as claimed in claim 9, wherein this reference capacitance module comprises:
A plurality of electric capacity, an end of described a plurality of electric capacity couples this switch module jointly; And
A plurality of switch elements, each described switch element are serially connected with respectively between this second reference voltage and described a plurality of electric capacity, and the control end of described a plurality of switch elements couples this control circuit;
This control circuit also is included in described a plurality of sense capacitance when not touched, the conducting of controlling each described switch element according to this integral result whether, to adjust the capacitance of this reference capacitance module.
CN 201010143201 2010-03-24 2010-03-24 Capacitance type touch control device and sensing device thereof Expired - Fee Related CN102200869B (en)

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