TWI505158B - Touch control detection circuit - Google Patents

Description

Touch detection circuit

The present invention relates to a touch circuit, and more particularly to a touch detection circuit.

With the development and advancement of technology, the user interface of electronic products has gradually evolved from a traditional button, keyboard or mouse to a more user-friendly touch interface. For example, the user can perform a touch operation on the light-sensitive touch panel by using a finger or a touch light pen. On the other hand, the light detecting circuit is often used in the touch panel to sense the current touch position of the user. For example, FIG. 1 is a schematic diagram of a light detecting circuit 100. The light detecting circuit 100 can be applied to the light sensing type touch panel to detect the touch point position of the touch panel.

The light detecting circuit 100 includes a transistor Q, a capacitor C, and a photodetecting transistor P. The scan line SCAN1 of the touch panel can be used to control the switching state of the transistor Q. The light detecting transistor P generates different current Ids under illumination of different intensities of light. One end of the capacitor C is coupled to the transistor Q, and the other end is coupled to the power source VDD. Capacitor C is used to store the charge generated by current Id. When the transistor Q is turned on, the charge stored in the capacitor C is transmitted to the data line of the touch panel via the transistor Q. DATA1. Since the current Id is different, the amount of charge in the capacitor C will also be different. Therefore, the photodetection circuit 100 can determine the current touch condition of the touch panel according to the amount of charge received by the data line DATA1.

However, when the light intensity detected by the photodetecting transistor P is insufficient or the sensing time is not long enough, the amount of charge stored in the capacitor C is too small, so that the voltage of the terminal VA is insufficient, and the touch panel cannot be judged. The location of the handle. On the other hand, the voltage difference between the gate G and the source S of the photodetecting transistor P (ie, Vgs) is usually operated under a negative bias to control the current Id, but this easily makes the photodetecting transistor P A situation in which deterioration occurs.

The invention provides a touch detection circuit for increasing the light sensing speed of the touch panel by increasing the light sensing speed of the touch detection circuit.

The touch detection circuit of the present invention includes a touch unit, a comparison unit, and a touch result generation unit. The touch unit provides a detection signal according to the touched state. The comparison unit couples the contact control unit and provides a reference current. The comparison unit generates a touch state current according to the detection signal and the voltage difference of the first reference voltage. The comparison unit compares the reference current and the touch state current to generate a comparison voltage. The touch result generating unit is coupled to the comparing unit and provides the touch result signal according to the comparison voltage.

Based on the above, the comparison unit in the touch detection circuit of the present invention generates a comparison voltage by comparing the voltage difference between the detection signal provided by the touch unit under different touch states and the first reference voltage. Then, the touch result generating unit will follow The touch result signal is provided according to the comparison voltage. In this way, the touch detection circuit of the present invention can know the current touch state of the touch panel by analyzing the touch result signal and know the position of the touch point on the touch panel.

The above described features and advantages of the invention will be apparent from the following description.

100‧‧‧Photodetection circuit

200, 300, 400, 500, 600, 700, 800‧‧‧ touch detection circuits

202, 302, 402, 502, 602, 702, 802 ‧ ‧ touch unit

204, 304, 404, 504, 604, 704, 804‧‧‧ comparison unit

206, 306, 406, 506, 606, 706, 806‧‧‧ touch result generation unit

A, B‧‧‧ curve

C, CT, CR‧‧‧ capacitor

DATA1, DATA3‧‧‧ data line

D1~D3‧‧‧ diode

F‧‧‧ waveform cycle

G‧‧‧ gate

Id‧‧‧ Current

IREF1‧‧‧reference current

IT1, IT2‧‧‧ touch state current

P, P1~P7‧‧‧Light detection transistor

S‧‧‧ source

SCAN1, SCAN3‧‧‧ scan line

SD1~SD6‧‧‧Detection signal

ST1, ST2‧‧‧ touch result signal

VA, VA1~VA3‧‧‧ endpoint

VCOMP, VCOMP1, VCOMP2‧‧‧ compare voltage

VREF1, VC2, VC4, T1, T2‧‧‧ reference voltage

VC1, VC3‧‧‧ reference voltage source

VC5‧‧‧ reference power supply

VDD‧‧‧ power supply

Q, M1~M6, MA, MB1~MB4, MC1~MC2, MD1~MD4, MF, MN‧‧‧O crystal

FIG. 1 is a schematic diagram of a light detecting circuit 100.

2 to 3A and 4 to 8 are schematic views respectively showing a touch detection circuit according to various embodiments of the present invention.

FIG. 3B is a schematic diagram of the readout waveform of the touch detection circuit 300 of FIG. 3A.

FIG. 2 is a schematic diagram of a touch detection circuit 200 according to an embodiment of the invention. The touch detection circuit 200 includes a touch unit 202, a comparison unit 204, and a touch result generation unit 206. The touch detection circuit 200 can be applied to a light-sensitive touch panel to detect the position of the touch point on the touch panel. The touch unit 202 provides the detection signal SD1 according to the touched state. The touch unit 202 can include a photo sensor, a thin film transistor (TFT), or other electronic components having a light detecting function. The intensity of the light perceived by the touch unit 202 may vary depending on whether the touch unit 202 is touched. In different touch states The touch unit 202 generates different detection signals SD1. The detection signal SD1 is a voltage signal.

On the other hand, the comparison unit 204 can be compared by TFT or other The electronic circuit consists of functions. The comparison unit 204 couples the contact control unit 202 to receive the detection signal SD1 and compares the voltage difference between the detection signal SD1 and the reference voltage VREF1 to generate different touch state currents. Next, the comparing unit 204 compares the touch state current with the reference current, and then generates the comparison voltage VCOMP. It is worth noting that the current value of the reference current can be preset to serve as a comparison reference.

The touch result generating unit 206 is coupled to the comparing unit 204, and the touch result is generated. The unit 206 receives the comparison voltage VCOMP and provides a touch result signal ST1 according to the comparison voltage VCOMP. For example, when the touch unit 202 is touched by the user's finger, the light received by the touch unit 202 is reduced by being shielded by the user's finger, and the voltage of the detection signal SD1 is less than the voltage of the reference voltage VREF1. . The comparison unit 204 calculates the voltage difference between the voltage of the detection signal SD1 and the reference voltage VREF1 to generate the comparison voltage VCOMP, and transmits the comparison voltage VCOMP to the touch result generation unit 206. The touch result generating unit 206 can amplify the comparison voltage VCOMP and provide a corresponding touch result signal ST1. As a result, the touch detection circuit 200 can learn that the touch unit 202 is currently touched by the touch result signal ST1.

Similarly, when the touch unit 202 is not touched, the touch unit 202 Since more light can be received without being obscured by the object, the voltage of the detection signal SD1 will A voltage greater than the reference voltage VREF1. In this manner, the touch detection circuit 200 can learn the different touch result signals ST1 by using the comparison voltage VCOMP different from the above example, and learn that the touch unit 202 is not used by using the different touch result signals ST1. The finger of the person touched.

It is worth mentioning that the current value of the above reference current can be set at Between the first current and the current value of the second current. The first current is the touch state current corresponding to the comparison unit 204 when the touch unit 202 is touched, and the second current is the touch corresponding to the comparison unit 204 when the touch unit 202 is not touched. Control the state current. For example, when the current value of the reference current can be equal to the voltage difference between the voltage of the detection signal SD1 and the reference voltage VREF1 is equal to 0, the comparison unit 204 corresponds to the current value of the generated touch state current.

FIG. 3A is a schematic diagram of a touch detection circuit 300 according to another embodiment of the present invention. Figure. The touch detection circuit 300 includes a touch unit 302, a comparison unit 304, and a touch result generation unit 306. The touch unit 302 includes a diode D1 and a photodetecting transistor P1. The anode of the diode D1 is coupled to the reference voltage source VC1, and the cathode of the diode D1 provides the detection signal SD2. In this embodiment, the photodetecting transistor P1 is an N-type TFT, and the photodetecting transistor P1 has a first end (eg, a drain), a second end (eg, a source), and a control end (eg, a gate). The first end of the photodetecting transistor P1 is coupled to the cathode of the diode D1. The second end of the photodetecting transistor P1 and the control end are coupled to the reference voltage VC2. From another point of view, a fixed resistance value can be provided when the diode D1 is turned on, and the photodetecting transistor P1 has a varying resistance value depending on the detected light intensity. Therefore, the touch unit 302 can be regarded as a voltage dividing circuit, wherein The diode D1 and the photodetecting transistor P1 divide the voltage difference between the reference voltage source VC1 and the reference voltage VC2 to generate the detection signal SD2.

The comparison unit 304 includes a diode D2 and a transistor M1. The anode of the diode D2 is coupled to the reference voltage source VC3, and the cathode of the diode D2 generates the comparison voltage VCOMP1. The diode D2 is used to generate the reference current IREF1. In this embodiment, the transistor M1 is an N-type TFT, and the transistor M1 has a first end (eg, a drain), a second end (eg, a source), and a control terminal (eg, a gate). The first end of the transistor M1 is coupled to the cathode of the diode D2, the control end of the transistor M1 is configured to receive the detection signal SD2, and the second end of the transistor M1 is coupled to the reference voltage VC4. Assuming that the detection signal SD2 is a voltage signal, the transistor M1 generates the touch state current IT1 according to the voltage difference between the detection signal SD2 and the reference voltage VC4.

For example, when the user's finger touches the touch unit 302, the light detected by the photodetecting transistor P1 may be less than when the user's finger does not touch the touch unit 302. Therefore, the leakage current generated by the photodetecting transistor P1 may be different under different touch states of the touch unit 302. In other words, the detection signal SD2 provided by the cathode terminal of the diode D1 will also be different. Therefore, for the transistor M1, the voltage difference (Vgs) generated between the control terminal and the second terminal of the touch unit 302 may be different under different touch states, and the transistor M1 is generated. The touch state current IT1 is different. In this embodiment, the reference current IREF1 provided by the diode D2 can be regarded as a fixed reference current. The comparison unit 304 compares the different touch state currents IT1 with the reference current IREF1, and generates a comparison voltage VCOMP1 according to the comparison result. For details, please refer to the following.

The touch result generating unit 306 includes a transistor MA and a transistor MN. In this embodiment, the transistor MA and the transistor MN are N-type TFTs. The transistor MA has a first end (e.g., a drain), a second end (e.g., a source), and a control terminal (e.g., a gate). The first end of the transistor MA receives the reference power source VC5, and the control end of the transistor MA is coupled to the comparison voltage VCOMP1. The transistor MN has a first end (e.g., a drain), a second end (e.g., a source), and a control terminal (e.g., a gate). The first end of the transistor MN is coupled to the second end of the transistor MA, the control end of the transistor MN is coupled to the scan line SCAN3, and the second end of the transistor MN generates the touch result signal ST2 and is coupled to the coupled Data line DATA3.

FIG. 3B is a schematic diagram of the readout waveform of the touch detection circuit 300 of FIG. 3A. The horizontal axis of FIG. 3B represents time, the unit may be microseconds (μs), and the vertical axis represents voltage, and the unit may be millivolts (mV), and F represents a waveform period. Please refer to FIG. 3A and FIG. 3B simultaneously. The curve A represents the voltage change of the drain of the transistor M1 when the touch unit 302 does not detect the change of light. On the other hand, the curve B represents the voltage change of the drain of the transistor M1 when the touch unit 302 detects a change in light. As can be seen from the curve B, when the touch unit 302 detects a change in light, the voltage of the drain of the transistor M1 only needs 0.01 F to reach the comparison voltage VCOMP1. From another point of view, the touch detection circuit 300 can reduce the light sensing time of the light detecting transistor P1 to increase the sensing speed.

The comparison unit 304 and the touch result generation unit 306 will be described in detail below. The action relationship between the two. The comparison voltage VCOMP1 generated by the comparison unit 304 is transmitted to the gate of the transistor MA. Here, the transistor MA can be used as a The amplifier is amplified according to the reference voltage VC5 and the comparison voltage VCOMP1 received by the control terminal. The amplified signal is transmitted to the transistor MN, and after the transistor MN is turned on, the amplified signal is transmitted to the data line DATA3 through the transistor MN to generate the touch result signal ST2.

FIG. 4 is a schematic diagram of a touch detection circuit 400 according to still another embodiment of the present invention. Figure. The touch detection circuit 400 includes a touch unit 402, a comparison unit 404, and a touch result generation unit 406. The touch unit 402 includes a transistor MD1 and a photodetecting transistor P2. In this embodiment, the transistor MD1 is an N-type TFT, and the transistor MD1 has a first end (eg, a drain), a second end (eg, a source), and a control terminal (eg, a gate). The first end of the transistor MD1 is coupled to the reference voltage source VC1. The second end of the transistor MD1 and the control terminal are coupled together and provide a detection signal SD3. The comparison unit 404 includes a transistor MB1 and a transistor M2. In this embodiment, the transistor MB1 and the transistor M2 are N-type TFTs, and the transistor MB1 has a first end (for example, a drain), a second end (for example, a source), and a control terminal (for example, a gate). The first end of the transistor MB1 receives the reference voltage source VC3, and the control terminal and the second end of the transistor MB1 are commonly coupled to the first end of the transistor M2. From another point of view, the diode D1 in FIG. 3 can be regarded as the transistor MD1 in FIG. 4, and the diode D2 can be regarded as the transistor MB1. On the other hand, please refer to FIG. 3 for the coupling relationship between the photodetecting transistor P2, the transistor M2, the reference voltage VC2, the reference voltage VC4, and the touch result generating unit 406, and details are not described herein.

The operation of the touch detection circuit 400 will be described below. Please refer to FIG. 3 at the same time. The transistor MD1 and the photodetecting transistor P2 are directed to the reference voltage source VC1 and The voltage difference of the reference voltage VC2 is divided to generate a detection signal SD3. On the other hand, since the control terminal and the second terminal of the transistor MB1 are coupled to each other, the voltage difference between the control terminal and the second terminal of the transistor MB1 is zero. The comparing unit 404 compares the voltage difference between the control terminal and the second terminal of the transistor MB1 (zero) and the voltage difference between the control terminal and the second terminal of the transistor M2 (the voltage difference between the detection signal SD3 and the reference voltage VC4) ). When the voltage difference between the detection signal SD3 and the reference voltage VC4 is greater than zero (for example, the touch unit 402 is touched by a finger), the voltage of the terminal VA1 approaches the reference voltage VC4. On the other hand, when the voltage difference between the control terminal and the second terminal of the transistor M2 is less than zero (for example, the touch unit 402 is not touched by a finger), the voltage of the terminal VA1 approaches the reference voltage source VC3. As a result, the touch unit 402 has a significant difference in the voltage of the terminal VA1 under different touch conditions.

FIG. 5 is a schematic diagram of a touch detection circuit 500 according to still another embodiment of the present invention. Figure. The touch detection circuit 500 includes a touch unit 502, a comparison unit 504, and a touch result generation unit 506. The touch unit 502 includes a transistor MD2 and a photodetecting transistor P3. The comparison unit 504 includes a transistor MB2 and a transistor M3. For the operation of the touch result generating unit 506, please refer to the touch result generating unit 306. Referring to FIG. 4 and FIG. 5 simultaneously, the difference between the touch detection circuit 400 and the touch detection circuit 500 is that the control terminal and the second end of the transistor M3 receive the reference voltage VC4 and the detection signal SD4, respectively. However, the coupling relationship of the transistor M2 is opposite to that of the transistor M3. The control terminal and the second terminal of the transistor M2 receive the detection signal SD3 and the reference voltage VC4, respectively.

FIG. 6 is a schematic diagram of a touch detection circuit 600 according to a further embodiment of the present invention. The touch detection circuit 600 includes a touch unit 602, a comparison unit 604, and a touch Result generation unit 606. The touch unit 602 includes a transistor MD3, a transistor MC1, a photodetecting transistor P4, and a photodetecting transistor P5. The comparison unit 604 includes a transistor MB3 and a transistor M4. As shown in FIG. 4 to FIG. 6 , the touch unit 602 has a light detecting transistor P5 and a transistor MC1 added to the touch unit 602 . The photodetecting transistor P5 and the transistor MC1 divide the voltage difference between the reference voltage source VC1 and the reference voltage VC4 to generate a reference voltage T1. The control terminal of the transistor M4 receives the detection signal SD5, and the second terminal of the transistor M4 receives the reference voltage T1.

In another embodiment, the transistor MD3 can be replaced by a diode, the anode of the diode is coupled to the reference voltage source VC1, and the cathode of the diode is used to provide the detection signal SD5. On the other hand, the transistor MC1 can also be replaced by a diode, the anode of which is coupled to the reference voltage source VC1, and the cathode of the diode is used to provide the reference voltage T1. In the embodiment of FIG. 6, when the light intensity received by the photodetecting transistor P4 and the photodetecting transistor P5 is changed, the detecting signal SD5 and the reference voltage T1 are also changed. On the other hand, please refer to FIG. 4 to FIG. 6. The second end of the transistor M2 in FIG. 4 and the control end of the transistor M3 in FIG. 5 are both coupled to the reference voltage VC4 (which can be regarded as a fixed voltage). However, the voltage difference between the control terminal (receiving detection signal SD5) of the transistor M4 and the second terminal (receiving the reference voltage T1) may vary greatly with the light intensity, thereby improving the touch detection. Sensitivity.

FIG. 7 is a schematic diagram of a touch detection circuit 700 according to still another embodiment of the present invention. The touch detection circuit 700 includes a touch unit 702, a comparison unit 704, and a touch result generation unit 706. The touch unit 702 includes a transistor MD4 and a transistor MC2. The light detecting transistor P6 and the light detecting transistor P7. The comparison unit 704 includes a transistor MF, a transistor MB4, and a transistor M5. In this embodiment, the transistor MF, the transistor MB4, and the transistor M5 are N-type TFTs. The transistor MF has a first end (eg, a drain), a second end (eg, a source), and a control terminal (eg, a gate). The first end of the transistor MF is coupled to the reference voltage source VC3, and the second end of the transistor MF generates the comparison voltage VCOMP2. The first end of the transistor MB4 is coupled to the second end of the transistor MF, and the second end of the transistor MB4 is coupled to the control end of the transistor MF. In another embodiment, the transistor MB4 can be replaced by a diode, the anode of the diode is coupled to the second end of the transistor MF, and the cathode of the diode is coupled to the control terminal of the transistor MF. The diode can be used to generate a reference current.

The transistor M5 has a first end (e.g., a drain), a second end (e.g., a source), and a control terminal (e.g., a gate). The first end of the transistor M5 is coupled to the second end of the transistor MB4, the control end of the transistor M5 receives the detection signal SD6, and the second end of the transistor M5 is coupled to the reference voltage T2. The transistor MF generates the touch state current IT2 according to the voltage difference between the detection signal SD6 and the reference voltage T2. Referring to FIG. 6 and FIG. 7 at the same time, it is worth noting that the comparison unit 704 is compared with the comparison unit 604, and the transistor MF is added to the comparison unit 704. The transistor MF can limit the current flowing to the transistor MC2 and the photodetecting transistor P7, and can limit the operating current consumed by the touch detecting circuit 700.

FIG. 8 is a schematic diagram of a touch detection circuit 800 according to another embodiment of the present invention. The touch detection circuit 800 can be applied to a capacitive touch panel. The touch detection circuit 800 includes a touch unit 802, a comparison unit 804, and a touch result generation unit 806. The touch unit 802 includes a touch detection capacitor CT and a reference capacitor CR. The first end of the touch detection capacitor CT receives the detection signal SD7, and the second end of the touch detection capacitor CT is used to provide the detection signal SD7. The reference capacitor CR is connected in series between the second end of the touch detection capacitor CT and the reference ground GND. The touch result generation unit 806 can be an analog digital converter. In this embodiment, the touch result generating unit 806 can know the touch condition of the touch panel by the voltage change of the end point VA3.

In summary, the touch detection circuit of the present invention uses the touch unit to provide different detection signals according to different touch states of the touch panel. Then, after receiving the detection signal, the comparison unit compares the detection signal with the reference voltage to generate a comparison voltage. Finally, the touch result generating unit amplifies the signal of the comparison voltage and provides a touch result signal. In this way, the touch detection circuit of the present invention can know the touch condition of the touch panel according to the touch result signal. In other words, the touch detection circuit of the present invention determines the touch situation of the current touch panel by analyzing the voltage difference generated by the touch panel under different touch states, so as to improve the sensitivity of the detection. Therefore, the touch detection circuit of the present invention can save the illumination time required for the photodetecting transistor to increase the detection speed and sensitivity.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

200‧‧‧Touch detection circuit

202‧‧‧Touch unit

204‧‧‧Comparative unit

206‧‧‧Touch result generation unit

SD1‧‧‧Detection signal

ST1‧‧‧ touch result signal

VREF1‧‧‧ reference voltage

VCOMP‧‧‧Comparative voltage

Claims (12)

A touch detection circuit includes: a touch unit that provides a detection signal according to the touched state; a comparison unit coupled to the touch unit to provide a reference current, and the comparison unit is based on the detection And a voltage difference between the signal and a first reference voltage to generate a touch state current, the comparing unit compares the reference current and the touch state current to generate a comparison voltage; and a touch result generating unit coupled to the comparing unit And providing a touch result signal according to the comparison voltage. The touch detection circuit of claim 1, wherein the touch unit comprises: a diode, the anode is coupled to a reference voltage source, the cathode provides the detection signal; and a light detection The transistor has a first end, a second end, and a control end, the first end of which is coupled to the cathode of the diode, and the second end and the control end of the photodetecting transistor are coupled to a second reference voltage . The touch detection circuit of claim 2, wherein the diode is a transistor having a first end, a second end, and a control end, and the first end of the transistor is coupled to the reference voltage The second end of the transistor and the control end are coupled together and provide the detection signal. The touch detection circuit of claim 2, wherein the photodetecting transistor and the diode are used for the reference voltage source and the second reference voltage The voltage difference is divided to generate the detection signal. The touch detection circuit of claim 1, wherein the comparison unit comprises: a diode, the anode is coupled to a reference voltage source, the cathode generates the comparison voltage, and the diode is used to generate a first transistor having a first end, a second end, and a control end, the first end of the first transistor being coupled to the cathode of the diode, and the second of the first transistor One of the terminal and the control terminal receives the detection signal, and the second end of the first transistor is coupled to the other one of the control terminals, the first transistor is configured according to the detection signal and the first transistor The voltage difference of the first reference voltage generates the touch state current. The touch detection circuit of claim 5, wherein the diode is a second transistor having a first end, a second end, and a control end, the first end of the second transistor receiving The reference voltage source, the control end of the second transistor and the second end are commonly coupled to the first end of the first transistor. The touch detection circuit of claim 1, wherein the touch unit comprises: a first diode, the anode is coupled to a reference voltage source, and the cathode provides the detection signal; The photodetecting transistor has a first end, a second end, and a control end, the first end of which is coupled to the cathode of the first diode, and the second end of the first photodetecting transistor and the control end are coupled to each other Connected to a second reference voltage; a second diode having an anode coupled to the reference voltage source and a cathode providing the second a reference voltage; and a second photodetecting transistor having a first end, a second end, and a control end, the first end of which is coupled to the cathode of the second diode, and the second photodetecting transistor The second end and the control end are coupled to each other to a third reference voltage. The touch detection circuit of claim 1, wherein the comparison unit comprises: a first transistor having a first end, a second end, and a control end, the first end of which is coupled to a reference voltage source The second end generates the comparison voltage; a diode having an anode coupled to the second end of the first transistor, a cathode coupled to the control end of the first transistor, the diode being used to generate The reference current; and a second transistor having a first end, a second end, and a control end, the first end of the first transistor is coupled to the cathode of the diode, and the control end of the second transistor Receiving the detection signal, and the second end of the second transistor is coupled to the first reference voltage, and the first transistor generates the touch state current according to the detection signal and a voltage difference of the first reference voltage . The touch detection circuit of claim 8, wherein the diode is a third transistor having a first end, a second end, and a control end, and the first end of the third transistor is coupled Connected to the second end of the first transistor, the second end of the third transistor and the control end are coupled to the first end of the second transistor. The touch detection circuit of claim 1, wherein the touch result generating unit comprises: a first transistor having a first end, a second end, and a control end, the first end thereof Receiving a reference power supply, the control end of the first transistor is coupled to the comparison voltage; and a second transistor having a first end, a second end, and a control end, the first end of which is coupled to the first transistor The second end of the second transistor receives a scan signal, and the second end of the second transistor generates the touch result signal. The touch detection circuit of the first aspect of the invention, wherein the touch unit comprises: a touch detection capacitor, one end of which receives a detection signal, and the other end of which provides the detection signal; and a reference The capacitor is connected in series between the second end of the touch detection capacitor and a reference ground. The touch detection circuit of claim 11, wherein the touch result generating unit is an analog digital converter.