Control circuit and display device

Abstract

A control circuit and a display device include a first input-output pin, a second input-output pin, a sensing circuit, and a display controller. The first input-output pin is used to couple a first input pin of a display device and a first sensing pin of a capacitive touch device. The second input-output pin is used to couple a second input pin of the display device and a second sensing pin of the capacitive touch device. During a display period, the display controller provides a first driving signal to the display device through the first input-output pin and provides a second driving signal to the display device through the second input-output pin. During a sensing period, the first input-output pin is equal to a preset level, and the sensing circuit detects a voltage of the second input-output pin.

Description

Technical Field

[0001] The present invention relates to a control circuit, and more particularly to a control circuit coupled to a display device and a touch device. Background Art

[0002] With technological advancements, the types and functions of electronic devices are increasing. Most electronic devices have an input device and an output device. A control device within the electronic device controls the operation of the electronic device based on information received by the input device and presents specific information through the output device. Touch devices and display devices are common input and output devices. However, because touch devices and display devices each have a large number of pins, the number of pins on the control device must be greater than the total number of pins on the touch device and display device in order to couple the touch device and display device. This reduces the available space within the electronic device. Summary of the Invention

[0003] The present invention provides a control circuit comprising a first input / output pin, a second input / output pin, a sensing circuit, and a display controller. The first input / output pin is used to couple a first input pin of a display device and a first sensing pin of a capacitive touch device. The second input / output pin is used to couple a second input pin of the display device and a second sensing pin of the capacitive touch device. The sensing circuit determines whether the capacitive touch device is touched based on the voltages of the first and second input / output pins. During a display period, the display controller provides a first drive signal to the display device via the first input / output pin, and provides a second drive signal to the display device via the second input / output pin. During a sensing period, the first input / output pin is equal to a preset level, and the sensing circuit detects the voltage of the second input / output pin.

[0004] The present invention further provides a display device comprising a display device, a capacitive touch device and a control circuit. The display device has a first input pin and a second input pin. The capacitive touch device has a first sensing pin and a second sensing pin. The control circuit comprises a first input / output pin, a second input / output pin, a sensing circuit and a display controller. The first input / output pin is coupled to the first input pin and the first sensing pin. The second input / output pin is coupled to the second input pin and the second sensing pin. The sensing circuit determines whether the capacitive touch device is touched based on the voltages of the first and second input / output pins. During a display period, the display controller provides a first drive signal to the display device via the first input / output pin, and provides a second drive signal to the display device via the second input / output pin. During a sensing period, the sensing circuit sets the first input / output pin to a preset level and detects the voltage of the second input / output pin. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 is a schematic diagram of an operating system of the present invention;

[0006] Figure 2 is a possible schematic diagram of the transmission circuit of the present invention;

[0007] Figure 3 is a possible schematic diagram of the sensing circuit of the present invention;

[0008] Figure 4 is a possible schematic diagram of a display device of the present invention;

[0009] Figure 5A is another schematic diagram of the operating system of the present invention;

[0010] Figure 5B is another schematic diagram of the operating system of the present invention;

[0011] Figures 6A to 6D is a schematic diagram of voltage changes of the first and second pin groups of the present invention;

[0012] Figure 7 is a schematic flow chart of a sensing operation performed by the control circuit of the present invention;

[0013] Figure 8A is a schematic diagram of a display area of ​​the present invention;

[0014] Figure 8B is another schematic diagram of the display area of ​​the present invention;

[0015] Figure 9 FIG. 4 is another schematic diagram of the control circuit of the present invention.

[0016] [Explanation of symbols]

[0017] 100, 500: operating system

[0018] 110, 510: Display device

[0019] 111, 511, 800A, 800B: Display area

[0020] 120, 520: Capacitive touch device

[0021] 121-124, 521-528: Area

[0022] 125-128: Sensing element

[0023] 130, 530, 900: Control circuit

[0024] 131: Image Driver

[0025] 132: Microcontroller Circuit

[0026] 133, 920: Sensing circuit

[0027] 134, 930: Transmission circuit

[0028] 135-138, IOA0-IOA3, IOB0-IOB3: Input and output pins

[0029] PN1~PN8, SEG0~SEG3, COM0~COM3, AN0~AN3, BN0~BN3: pins

[0030] SD1~SD4, SSG0, SCM0: drive signal

[0031] V PN5 ~V PN8 、V AN3 、V BN0 :Voltage

[0032] SEL: switching signal

[0033] SW1, SW2, 931, 932: Switching circuit

[0034] PA1-PA8: Path

[0035] 310-340: Sensing unit

[0036] Cmp, Cmn, 820: capacitance

[0037] 313: Comparator

[0038] 314: Controller

[0039] DK: reference voltage

[0040] 311, 312: Node

[0041] SCM: Comparison signal

[0042] Sap, San: Adjust the signal

[0043] P 11 ~P 44 :pixel

[0044] ST1~ST4: Open signal

[0045] R1~R8:resistance

[0046] 611, 613, 614, 616, 617, 619, 621, 623, 624, 626, 627, 629, 631, 633, 634, 636, 637, 639, 641, 643, 644, 646, 647, 649: Display period

[0047] 612, 615, 618, 622, 625, 628, 632, 635, 638, 642, 645, 648: Sensing period

[0048] L1~L8、VDD、GND:Level

[0049] S711~S716: Steps

[0050] 810: Light Emitting Diode

[0051] 910: Display controller DETAILED DESCRIPTION

[0052] To make the objectives, features, and advantages of the present invention more readily apparent, the following examples are presented and described in detail with reference to the accompanying drawings. This specification provides various examples to illustrate the technical features of various embodiments of the present invention. The configurations of the various components in the examples are for illustrative purposes only and are not intended to limit the present invention. Furthermore, any repetition of reference numerals in the figures of the examples is for simplification and does not imply a correlation between the different examples.

[0053] Figure 1 Schematic diagram of the operating system of the present invention. As shown in the figure, the operating system 100 includes a display device 110, a capacitive touch device 120, and a control circuit 130. The display device 110 has pins PN1 to PN4 and a display area 111. The display area 111 displays the image according to the voltage levels of the pins PN1 to PN4. The present invention does not limit the number of pins of the display device 110. In addition, the present invention does not limit the type of the display device 110. In one possible embodiment, the display device 110 is a super twisted liquid-crystal display panel (STN LCD panel).

[0054] The capacitive touch device 120 includes regions 121-124, sensing elements 125-128, and pins PN5-PN8, but this is not intended to limit the present invention. In other embodiments, the capacitive touch device 120 may have other numbers of regions, sensing elements, and pins. The present invention is not limited to the type of capacitive touch device 120. In one embodiment, the capacitive touch device 120 is a touch keyboard or a touch pad.

[0055] In this embodiment, the sensing element 125 is arranged in the area 121 to determine whether the area 121 is touched, the sensing element 126 is arranged in the area 122 to determine whether the area 122 is touched, the sensing element 127 is arranged in the area 123 to determine whether the area 123 is touched, and the sensing element 128 is arranged in the area 124 to determine whether the area 124 is touched. In one possible embodiment, the sensing elements 125 to 128 are capacitive sensing elements. Pin PN5 outputs the sensing result of the sensing element 125. Pin PN6 outputs the sensing result of the sensing element 126. Pin PN7 outputs the sensing result of the sensing element 127 respectively. Pin PN8 outputs the sensing result of the sensing element 128 respectively. Taking the sensing element 125 as an example, when the area 121 is not touched, the capacitance of the sensing element 125 remains unchanged. At this time, the voltage V of the pin PN5 PN5 However, when the area 121 is touched, the capacitance of the sensing element 125 will change (may become larger), so the voltage V PN5 will not be equal to the reference voltage. For example, the voltage V PN5 May be less than the reference voltage.

[0056] The control circuit 130 includes an image driver 131, a microcontroller circuit 132, a sensing circuit 133, a transmission circuit 134, and input / output pins 135 to 138. The image driver 131 is used to drive the display device 110. In this embodiment, the image driver 131 generates drive signals SD1 to SD4, but this is not intended to limit the present invention. In other embodiments, the image driver 131 may generate more or fewer drive signals. The present invention does not limit the circuit architecture of the image driver 131. In one possible embodiment, the image driver 131 is a liquid crystal driver (LCD driver). In another possible embodiment, the image driver 131 is a COM / SEG driver (COM / SEG driver) for generating COM / SEG waveforms.

[0057] The sensing circuit 133 is used to detect whether the capacitive touch device 120 is touched and the touch position. The present invention does not limit how the sensing circuit 133 detects whether the capacitive touch device 120 is touched. In one possible embodiment, the sensing circuit 133 first provides a reference voltage DK to the pins PN5 to PN8 of the capacitive touch device 120, and then detects whether the voltage levels of the pins PN5 to PN8 change. When the voltage levels of the pins PN5 to PN8 change, it indicates that the corresponding area is touched. For example, when the voltage V PN5 When the voltage V of the pin PN5 is not equal to the reference voltage DK, it indicates that the area 121 corresponding to the pin PN5 is touched. PN5 When the voltage is equal to the reference voltage DK, it indicates that the region 121 corresponding to the pin PN5 is not touched. In some embodiments, the reference voltage DK is less than 1 volt.

[0058] Transmission circuit 134 includes switching circuits SW1 and SW2. Switching circuit SW1 is coupled between image driver 131 and input / output pins 135-138 and is controlled by a switching signal SEL. When switching signal SEL turns on switching circuit SW1, switching circuit SW1 transmits drive signals SD1-SD4 to input / output pins 135-138. In this state, input / output pins 135-138 function as output pins, outputting drive signals SD1-SD4 to display device 110.

[0059] The switching circuit SW2 is coupled between the sensing circuit 133 and the input / output pins 135-138 and is controlled by the switching signal SEL. When the switching signal SEL turns on the switching circuit SW2, the switching circuit SW2 may first transmit the reference voltage DK to the input / output pins 135-138 and then transmit the voltage V PN5 ~V PN8 to the sensing circuit 133 .

[0060] In this embodiment, the input and output pins 135-138 are used to transmit analog signals. In other words, the driving signals SD1-SD4 and the voltage V PN5 ~V PN8 All are analog signals. Furthermore, in this embodiment, the display device 110 and the capacitive touch device 120 share input and output pins 135-138, thereby reducing the number of input and output pins of the control circuit 130. In other embodiments, the display device 110 and the capacitive touch device 120 may share more or fewer input and output pins.

[0061] Since the characteristics of the input and output pins 135 to 138 are the same, the following content takes the input and output pin 135 as an example. Figure 1As shown, the input / output pin 135 is coupled to the pin PN1 of the display device 110 and the pin PN5 of the capacitive touch device 120. When the switching circuit SW1 is turned on, the input / output pin 135 transmits the driving signal SD1. When the switching circuit SW2 is turned on, the input / output pin 135 transmits the reference voltage DK and the voltage V PN5 .

[0062] In one embodiment, the voltages V at the pins PN5 to PN8 are PN5 ~V PN8 Therefore, even if the pins PN5 to PN8 are coupled to the pins PN1 to PN4, the voltage V PN5 ~V PN8 It also does not affect the image displayed by the display device 110 .

[0063] For example, assume that the maximum voltage of the driving signals SD1-SD4 is 4V. In this example, the voltage V PN5 ~V PN8 The maximum voltage of is about 1.3V (ie, one-third of the voltage of the driving signals SD1-SD4) or 1V (ie, one-quarter of the voltage of the driving signal SD1). PN5 ~V PN8 is very small, so the image displayed by the display device 110 will not be affected by the voltage V PN5 ~V PN8 In other embodiments, the voltage V PN5 ~V PN8 Less than 1V.

[0064] The micro-control circuit 132 generates a switching signal SEL to control the switching circuits SW1 and SW2. In this embodiment, the switching circuits SW1 and SW2 are not simultaneously turned on. For example, when the micro-control circuit 132 turns on the switching circuit SW1, the micro-control circuit 132 turns off the switching circuit SW2. When the micro-control circuit 132 turns on the switching circuit SW2, the micro-control circuit 132 turns off the switching circuit SW1.

[0065] The present invention is not limited to the circuit architecture of the microcontroller 132. In one embodiment, the microcontroller 132 is a microcontroller (MCU). In this embodiment, the microcontroller 132 uses a single switching signal (e.g., SEL) to control the switching circuits SW1 and SW2, but this is not intended to limit the present invention. In other embodiments, the microcontroller 132 uses two switching signals to control the switching circuits SW1 and SW2, respectively.

[0066] In other embodiments, the microcontroller 132 further triggers the image driver 131 and the sensing circuit 133. When the image driver 131 is triggered, it generates driving signals SD1-SD4. At this point, the microcontroller 132 activates the switching circuit SW1 and deactivates the switching circuit SW2 via the switching signal SEL. Consequently, the input / output pins 135-138 output the driving signals SD1-SD4 to the display device 110. The display device 110 displays images based on the driving signals SD1-SD4.

[0067] When the microcontroller 132 triggers the sensing circuit 133, the sensing circuit 133 generates a reference voltage DK. At this time, the microcontroller 132 turns on the switching circuit SW2 and turns off the switching circuit SW1 through the switching signal SEL. Therefore, the input and output pins 135-138 first output the reference voltage DK to the sensing circuit 133, and then provide the voltage V PN5 ~V PN8 To the sensing circuit 133. In this example, the sensing circuit 133 is based on the voltage V PN5 ~V PN8 , determine whether areas 121 to 124 are touched.

[0068] In other embodiments, when the microcontroller 132 triggers the sensing circuit 133, the microcontroller 132 may instruct the image driver 131 to suspend generating the driving signals SD1-SD4. In some embodiments, the image driver 131 may continue to generate the driving signals SD1-SD4. However, because the microcontroller 132 does not turn on the switching circuit SW1, the switching circuit SW1 does not transmit the driving signals SD1-SD4 to the input / output pins 135-138. In this example, because the display device 110 includes a charge storage element, the display device 110 can maintain the display even without receiving the driving signals SD1-SD4.

[0069] In this embodiment, the switching circuit SW2 is turned on for a shorter time than the switching circuit SW1. For example, the switching circuit SW2 may be turned on for one tenth of the switching circuit SW1. Therefore, even if the switching circuit SW1 temporarily stops transmitting the driving signals SD1-SD4, the image displayed by the display device 110 will not be affected by the voltage V PN5 ~V PN9 In one embodiment, the switching circuit SW1 is turned on for approximately 250 μs, and the switching circuit SW2 is turned on for approximately 250 ns.

[0070] In addition, due to the voltage V PN5 ~VPN8 is very small, so even if the display device 110 receives the voltage V PN5 ~V PN8 The image displayed by the display device 110 will not be affected by the voltage V PN5 ~V PN8 In one embodiment, the voltage V PN5 ~V PN8 It may be less than one third of the driving signals SD1-SD4. In another embodiment, the voltage V PN5 ~V PN8 It may be less than one quarter of the driving signals SD1-SD4. In other embodiments, the voltage V PN5 ~V PN8 Less than 1V.

[0071] The present invention does not limit when the micro-control circuit 132 turns on the switching circuit SW2. Assuming that the display device 110 displays multiple frames within one second, in one embodiment, the micro-control circuit 132 turns on the switching circuit SW2 between two frames displayed by the display device 110. In another embodiment, the micro-control circuit 132 turns on the switching circuit SW2 at least once during the time it takes for the display device 110 to display a frame.

[0072] Figure 2 FIG. 1 is a possible schematic diagram of the transmission circuit 134 of the present invention. Figure 2 As shown, the switching circuit SW1 is coupled between the image driver 131 and the input / output pins 135-138 and has paths PA1-PA4. In this embodiment, the paths PA1-PA4 transmit the driving signals SD1-SD4 to the input / output pins 135-138 according to the switching signal SEL.

[0073] For example, when the switching signal SEL turns on paths PA1-PA4, paths PA1-PA4 transmit drive signals SD1-SD4 to input / output pins 135-138. When the switching signal SEL turns off paths PA1-PA4, paths PA1-PA4 stop transmitting drive signals SD1-SD4 to input / output pins 135-138. The present invention is not limited to the architecture of switching circuit SW1. In one embodiment, switching circuit SW1 includes multiple switches to provide paths PA1-PA4. In this embodiment, paths PA1-PA4 are either simultaneously conductive or simultaneously non-conductive. In other embodiments, when one of paths PA1-PA4 is conductive, at least one of paths PA1-PA4 is non-conductive.

[0074] The switching circuit SW2 has paths PA5 to PA8. The path PA5 is coupled between the sensing circuit 133 and the input / output pin 135 and transmits the reference voltage DK and the voltage V of the pin PN5 according to the switching signal SEL. PN5 The path PA6 is coupled between the sensing circuit 133 and the input / output pin 136, and transmits the reference voltage DK and the voltage V of the pin PN6 according to the switching signal SEL. PN6 The path PA7 is coupled between the sensing circuit 133 and the input / output pin 137, and transmits the reference voltage DK and the voltage V of the pin PN7 according to the switching signal SEL. PN7 The path PA8 is coupled between the sensing circuit 133 and the input / output pin 138, and transmits the reference voltage DK and the voltage V of the pin PN8 according to the switching signal SEL. PN8 For example, when the switching signal SEL turns on the paths PA5-PA8, the paths PA5-PA8 first transmit the reference voltage DK to the input / output pins 135-138, and then transmit the voltage V 135 ~V 138 To the sensing circuit 133. When the switching signal SEL does not conduct the paths PA5-PA8, the paths PA5-PA8 stop transmitting the reference voltage DK and the voltage V 135 ~V 138 In this embodiment, the paths PA5-PA8 are either conductive or non-conductive at the same time. In other embodiments, when one of the paths PA5-PA8 is conductive, the other one of the paths PA5-PA8 is non-conductive.

[0075] In one embodiment, paths coupled to the same I / O pin are not simultaneously conductive. Taking I / O pin 135 as an example, I / O pin 135 is coupled to paths PA1 and PA5. In this example, when path PA1 is conductive, path PA5 is non-conductive. When path PA5 is conductive, path PA1 is non-conductive. The present invention is not limited to the architecture of switching circuit SW2. In one embodiment, switching circuit SW2 includes multiple switches to provide paths PA5-PA8.

[0076] Figure 3 This is a possible schematic diagram of a sensing circuit according to the present invention. Sensing circuit 133 includes sensing units 310-340. Sensing unit 310 determines whether region 121 of capacitive touch device 120 is touched. Sensing unit 320 determines whether region 122 of capacitive touch device 120 is touched. Sensing unit 330 determines whether region 123 of capacitive touch device 120 is touched. Sensing unit 340 determines whether region 124 of capacitive touch device 120 is touched. Since sensing units 310-340 have the same structure, only the structure and operation of sensing unit 310 will be described below.

[0077] Sensing unit 310 includes capacitors Cmp and Cmn, a comparator 313, and a controller 314. Capacitor Cmp is coupled between node 311 and the non-inverting input of comparator 313 to provide a reference voltage DK. Capacitor Cmn is coupled between the inverting input of comparator 313 and node 312. In other embodiments, capacitor Cmn may be coupled between the inverting input of comparator 313 and node 311. In this embodiment, capacitors Cmp and Cmn are both variable capacitors.

[0078] The non-inverting input terminal of the comparator 313 is coupled to the capacitor Cmp for receiving the reference voltage DK. The inverting input terminal of the comparator 313 receives the voltage V PN8 In this embodiment, the comparator 313 compares the reference voltage DK with the voltage V PN8 , for generating a comparison signal SCM.

[0079] The controller 314 determines whether a specific area (e.g., area 124) of the capacitive touch device 120 is touched based on the comparison signal SCM. In one embodiment, the controller 314 first generates a reference voltage DK and then provides the reference voltage DK to the non-inverting input of the comparator 313. The controller 314 then determines whether the specific area of ​​the capacitive touch device 120 is touched based on the voltage at the inverting input of the comparator 313. In this embodiment, the controller 314 determines the touch force based on the voltage at the inverting input of the comparator 313.

[0080] For example, during an initial period, the controller 314 first provides a preset voltage to nodes 311 and 312. Consequently, capacitors Cmp and Cmn begin to store charge, generating a reference voltage DK. At this point, the voltages at the inverting and non-inverting inputs of the comparator 313 are approximately equal to the reference voltage DK. If the switching circuit SW2 is turned on, it transmits the reference voltage DK to pins PN5-PN8 of the capacitive touch device 120.

[0081] In this example, when the region 124 of the capacitive touch device 120 is touched, the capacitance of the sensing element 128 in the region 124 changes, causing the voltage V PN8 changes and is no longer equal to the reference voltage DK. Since the voltage at the inverting input of the comparator 313 (i.e., V PN8 ) is not equal to the voltage of the non-inverting input terminal (ie, DK), so the controller 314 knows that the area 124 is touched.

[0082] In one embodiment, the controller 314 generates adjustment signals Sap and San to adjust the capacitance of capacitors Cmp and Cmn so that the voltage at the inverting input of the comparator 313 is equal to the voltage at the non-inverting input (i.e., DK). After the voltage at the inverting input of the comparator 313 is equal to the voltage at the non-inverting input, the controller 314 determines the strength of the touch based on the adjustment amplitude of the capacitance of capacitors Cmp and Cmn. In one embodiment, the controller 314 generates a notification signal to notify the microcontroller 132 of the touch event.

[0083] Figure 4 FIG. 1 is a possible schematic diagram of a display device 100 of the present invention. As shown in the figure, the display device 100 has a pixel P 11 ~P 44 , but is not intended to limit the present invention. In other embodiments, the display device 100 has more or fewer pixels. In this embodiment, the display device 100 is an active matrix (AM) liquid crystal display. In this example, the pixel P 11 ~P 44 According to the start signals ST1-ST4, the data signals DA1-DA4 are received and stored. 11 For example, pixel P 11 According to the start signal ST1, the data signal SD1 is received and stored. In one embodiment, the pixel P 11 ~P 44 Each of them has a storage capacitor (not shown) for storing data signals DA1 - DA4 .

[0084] In one embodiment, the start-up signals ST1-ST4 are drive signals SD1-SD4. In this example, the data signals DA1-DA4 may be generated by the image driver 131. The image driver 131 may provide the data signals DA1-DA4 to the display device 110 via other input / output pins. These input / output pins (i.e., the input / output pins that transmit the data signals DA1-DA4) may or may not be coupled to the capacitive touch device 120.

[0085] In another embodiment, the data signals DA1-DA4 are driving signals SD1-SD4. In this example, the image driver 131 may provide the start signals ST1-ST4 to the display device 110 via other input / output pins. These input / output pins (i.e., the input / output pins that transmit the start signals ST1-ST4) may or may not be coupled to the capacitive touch device 120.

[0086] In other embodiments, the driving signals SD1-SD4 are COM / SEG signals. 11~P 44 According to the start-up signals ST1 - ST4 and the COM / SEG signal, the data signals DA1 - DA4 are received and stored.

[0087] In some embodiments, the display device 100 is a passive matrix (PM) display. In this example, the driving signals SD1-SD4 are referred to as common signals, and the data signals DA1-DA4 are referred to as segment signals. The potentials of the driving signals SD1-SD4 and the data signals DA1-DA4 are used to change the pixel P. 11 ~P 44 In one embodiment, the pixel P 11 ~P 44 Therefore, once the driving signals SD1-SD4 and the data signals DA1-DA4 disappear, the pixel P 11 ~P 44 The liquid crystal molecules will return to their original positions.

[0088] In other embodiments, the display device 110 further includes a driving circuit (not shown). In this example, the driving circuit may generate the start signals ST1-ST4 or the data signals DA1-DA4 based on the driving signals SD1-SD4. In some embodiments, the driving circuit of the display device 110 generates the start signals ST1-ST4 and the data signals DA1-DA4 based on the driving signals SD1-SD4.

[0089] In this embodiment, since the display device 110 and the capacitive touch device 120 share input and output pins (such as 135-138), the number of input and output pins of the amplitude control circuit 130 can be reduced. PN5 ~V PN8 is much smaller than the voltage of the pins PN1 to PN4 of the display device 110. Therefore, the display device 110 is not affected by the voltage V PN5 ~V PN8 Furthermore, the capacitive touch device 120 outputs a voltage V PN5 ~V PN8 The time is very short, so the voltage V PN5 ~V PN8 The display device 110 is not affected.

[0090] Figure 5AThis is another schematic diagram of an operating system according to the present invention. As shown, operating system 500 includes a display device 510, a capacitive touch device 520, and a control circuit 530. In one embodiment, operating system 500 is a display system. In this example, display device 510, capacitive touch device 520, and control circuit 530 are integrated into a display device.

[0091] Display device 510 has a display area 511, input pins SEG0-SEG3, and COM0-COM3. In one embodiment, each of input pins SEG0-SEG3 receives a segment signal, and each of input pins COM0-COM3 receives a common signal. Display area 511 has a plurality of pixels (not shown). Each pixel is coupled to one of input pins SEG0-SEG3 and one of pins COM0-COM3. The voltage difference between one of input pins SEG0-SEG3 and one of pins COM0-COM3 activates the corresponding pixel.

[0092] The present invention is not limited to the type of display device 510. In one embodiment, the display device 510 is an active matrix display. In this case, each pixel may include a driving transistor (not shown) and a storage capacitor (not shown). The driving transistor charges the storage capacitor, thereby activating the corresponding pixel.

[0093] In another embodiment, display device 510 is a passive matrix display, such as a twisted nematic liquid crystal display (TN LCD) panel or a super twisted nematic liquid crystal display (STN LCD) panel. In this example, each pixel of the passive matrix display may have a liquid crystal capacitor, without a driver transistor or storage capacitor. One end of the liquid crystal capacitor is directly connected to one of the input pins SEG0-SEG3, and the other end of the liquid crystal capacitor is directly connected to one of the input pins COM0-COM3.

[0094] In other embodiments, display device 510 is a passive matrix organic light-emitting diode (PMOLED) display. In this example, each pixel of display device 510 has only one light-emitting diode (LED), without a driver transistor or storage capacitor. One end of the LED (e.g., the anode) is directly connected to one of input pins SEG0-SEG3, and the other end of the LED (e.g., the cathode) is directly connected to one of input pins COM0-COM3.

[0095] The capacitive touch device 520 includes sensing areas 521 to 528, sensing pins AN0 to AN3, and BN0 to BN3. In one embodiment, each sensing area has at least one sensing element, such as a touch sensor. The touch sensor is used to determine whether the corresponding sensing area is touched. Figure 1 The characteristics of the sensing elements 125 to 128 are the same, so they will not be described in detail.

[0096] Sensing pins AN0-AN3 and BN0-BN3 output signals generated by the sensing elements in sensing regions 521-528. In one embodiment, each sensing region has a sensing element. In this example, each sensing pin AN0-AN3 and BN0-BN3 corresponds to a sensing element. For example, sensing regions 521-524 are electrically connected to sensing pins BN0-BN3, respectively. Sensing regions 525-528 are electrically connected to sensing pins AN0-AN3, respectively. In this embodiment, sensing pins AN0-AN3 are electrically connected to input pins SEG3-SEG0, respectively. Sensing pins BN0-BN3 are electrically connected to input pins COM0-COM3, respectively.

[0097] In other embodiments, the capacitive touch device 520 may have more or fewer sensing areas and sensing pins. The present invention is not limited to the type of the capacitive touch device 520. In one embodiment, the capacitive touch device 520 is a touch keyboard or a touch pad. In other embodiments, the capacitive touch device 520 may cover the display device 510.

[0098] The control circuit 530 has input / output pins IOA0-IOA3 and IOB0-IOB3. The input / output pins IOA0-IOA3 are electrically connected to the input pins SEG0-SEG3 and the sensing pins AN3-AN0. The input / output pins IOB0-IOB3 are electrically connected to the input pins COM0-COM3 and the sensing pins BN0-BN3. In this embodiment, since the display device 510 and the capacitive touch device 520 share the input / output pins IOA0-IOA3 and IOB0-IOB3, the number of input / output pins of the control circuit 530 can be reduced.

[0099] During a display period, the control circuit 530 provides segment signals to input pins SEG0-SEG3 via input / output pins IOA0-IOA3, and provides common signals to input pins COM0-COM3 via input / output pins IOB0-IOB3. At this time, the display device 510 displays images based on the potentials of input pins SEG0-SEG3 and COM0-COM3.

[0100] During a first sensing period, the control circuit 530 scans the voltage levels of a portion of the I / O pins IOA0-IOA3 and IOB0-IOB3 to determine whether the capacitive touch device 520 is touched. The scanned I / O pins constitute a first pin group. While scanning the first pin group, the control circuit 530 may set the voltage levels of another portion of the I / O pins IOA0-IOA3 and IOB0-IOB3 to a first predetermined level. In this example, the I / O pins set by the control circuit 530 constitute a second pin group. In other embodiments, the control circuit 530 may set the impedance of each pin in the second pin group to a high impedance state (High Impedance). During the first sensing period, after the control circuit 530 has scanned the voltage levels of all pins in the first pin group, it may scan the voltage levels of all pins in the second pin group. When the control circuit 530 scans the second pin group, the control circuit 530 sets the voltage levels of all pins of the first pin group to be equal to a second predetermined level, or sets the impedance of each pin of the first pin group to a high impedance state.

[0101] In other embodiments, the control circuit 530 scans the voltage levels of all pins of the second pin group during the second sensing period. In this example, the control circuit 530 sets the voltage level of each pin of the first pin group to a second predetermined level, or sets the impedance of each pin of the first pin group to a high impedance state.

[0102] In one embodiment, the input / output pins IOA0-IOA3 transmit the same type of signals. Therefore, the control circuit 530 treats the input / output pins IOA0-IOA3 as a first pin group. Furthermore, because the input / output pins IOB0-IOB3 transmit the same type of signals, the control circuit 530 treats the input / output pins IOB0-IOB3 as a second pin group.

[0103] Figure 5B FIG. 4 is another schematic diagram of the operating system of the present invention. Figure 5B resemblance Figure 5A , the difference is that, Figure 5BResistors R1 through R8 are added. Resistors R1 through R4 are coupled between input / output pins IOA0 through IOA3 and input pins SEG0 through SEG3, respectively. Resistors R5 through R8 are coupled between input / output pins IOB0 through IOB3 and input pins COM0 through COM3, respectively. Taking resistors R1 and R5 as an example, resistor R1 is coupled between input / output pin IOA0 and input pin SEG0, and resistor R5 is coupled between input / output pin IOB0 and input pin COM0. In one embodiment, the impedance of resistors R1 through R8 is approximately between 1 kΩ and 10 kΩ.

[0104] In some embodiments, the display device 510 is a liquid crystal display device. Resistors R1 to R8 are used to increase the accuracy of the sensing operation. In this example, the control circuit 530 performs a sensing operation to detect the touched area of ​​the capacitive touch device 520.

[0105] Figures 6A to 6D Schematic diagram of voltage level changes of the first and second pin groups of the present invention. Assume that the input and output pins IOA0 to IOA3 belong to the first pin group, and the input and output pins IOB0 to IOB3 belong to the second pin group. Since the characteristics of the input and output pins IOA0 to IOA3 are the same, Figures 6A to 6D Only the level change of I / O pin IOA0 is shown. In addition, since the characteristics of I / O pins IOB0 to IOB3 are the same, Figures 6A to 6D Only the level change of I / O pin IOB0 is displayed.

[0106] exist Figure 6ADuring display period 611, the control circuit 530 sets the voltage level of I / O pin 10A0 to level L1 and the voltage level of I / O pin 10B0 to level L3. At this time, the display device 510 displays images based on the voltage levels of I / O pins 10A0 and 10B0. During sensing period 612, the control circuit 530 sets the voltage level of I / O pin 10A0 (first pin group) to a floating level. In one embodiment, the control circuit 530 does not apply any voltage to I / O pin 10A0. In this example, the impedance of I / O pin 10A0 is in a high impedance state. Therefore, I / O pin 10A0 is at a floating level. During sensing period 612, the control circuit 530 detects the voltage level of I / O pin 10B0 (second pin group). In one embodiment, the control circuit 530 first applies a reference voltage to I / O pin 10B0 and then determines whether the voltage of I / O pin 10B0 has changed. If so, it indicates that the sensing area corresponding to I / O pin IOB0 has been touched. In some embodiments, during sensing period 612, control circuit 530 sequentially detects the voltage levels of I / O pins IOB0-IOB3 (a second pin group). During display period 613, control circuit 530 resets the voltage level of I / O pin IOA0 to level L1 and sets the voltage level of I / O pin IOB0 to level L3. As a result, display device 510 displays the corresponding image.

[0107] During display period 614, control circuit 530 sets the voltage level of input / output pin 10A0 to level L2 and the voltage level of input / output pin 10B0 to level L4. During sensing period 615, control circuit 530 sets the voltage level of input / output pin 10A0 to a floating level. During this period, control circuit 530 detects the voltage levels of input / output pins IOB0-IOB3. During display period 616, control circuit 530 sets the voltage level of input / output pin 10A0 to level L2 and the voltage level of input / output pin 10B0 to level L4.

[0108] During display period 617, the control circuit 530 sets the voltage level of I / O pin 10A0 to level L2 and the voltage level of I / O pin 10B0 to level L4. During sensing period 618, the control circuit 530 sets the voltage level of I / O pin 10A0 to a floating level. During this period, the control circuit 530 scans the voltage levels of I / O pins IOB0-IOB3. During display period 619, the control circuit 530 sets the voltage level of I / O pin 10A0 to level L2 and the voltage level of I / O pin 10B0 to level L4.

[0109] exist Figure 6BDuring display period 621, the control circuit 530 sets the voltage level of input / output pin IOB0 to level L5 and the voltage level of input / output pin IOA0 to level L7. Therefore, the display device 510 presents a corresponding image based on the voltage levels of input / output pins IOA0 and IOB0. During sensing period 622, the control circuit 530 sets the voltage level of input / output pin IOB0 to a floating level and sequentially scans the voltage levels of input / output pins IOA0-IOA3. During display period 623, the control circuit 530 again sets the voltage level of input / output pin IOB0 to level L5 and the voltage level of input / output pin IOA0 to level L7. Therefore, the display device 510 presents a corresponding image based on the voltage levels of input / output pins IOA0 and IOB0.

[0110] During display period 624, control circuit 530 sets the voltage level of I / O pin IOB0 to level L6 and sets the voltage level of I / O pin IOA0 to level L8. During sensing period 625, control circuit 530 sets the voltage level of I / O pin IOB0 to a floating level and scans the voltage levels of I / O pins IOA0-IOA3. During display period 626, control circuit 530 sets the voltage level of I / O pin IOB0 to level L6 and sets the voltage level of I / O pin IOA0 to level L8.

[0111] During display period 627, the control circuit 530 sets the voltage level of I / O pin IOB0 to level L6 and the voltage level of I / O pin IOA0 to level L7. During sensing period 628, the control circuit 530 sets the voltage level of I / O pin IOB0 to a floating level. During this period, the control circuit 530 scans the levels of I / O pins IOA0-IOA3. During display period 629, the control circuit 530 sets the voltage level of I / O pin IOB0 to level L6 and the voltage level of I / O pin IOA0 to level L7.

[0112] exist Figure 6CDuring display period 631, the control circuit 530 sets the voltage level of input / output pin 10A0 to level VDD and the voltage level of input / output pin 10B0 to level GND. Therefore, the display device 510 displays a corresponding image based on the voltages of input / output pins 10A0 and 10B0. During sensing period 632, the control circuit 530 sets the voltage level of input / output pin 10A0 to level GND (or a first preset level) and scans the voltage levels of input / output pins IOB0-IOB3. During display period 633, the control circuit 530 again sets the voltage level of input / output pin 10A0 to level VDD and sets the voltage level of input / output pin 10B0 to level GND. Therefore, the display device 510 displays a corresponding image based on the voltages of input / output pins 10A0 and 10B0.

[0113] During display period 634, the control circuit 530 sets the voltage level of input / output pin 10A0 to GND and the voltage level of input / output pin 10B0 to VDD. During sensing period 635, the control circuit 530 sets the voltage level of input / output pin 10A0 to GND. During this period, the control circuit 530 scans the voltage levels of input / output pins IOB0-IOB3. During display period 636, the control circuit 530 sets the voltage level of input / output pin 10A0 to GND and the voltage level of input / output pin 10B0 to VDD.

[0114] During display period 637, the control circuit 530 sets the voltage level of input / output pin 10A0 to GND and the voltage level of input / output pin 10B0 to VDD. During sensing period 638, the control circuit 530 sets the voltage level of input / output pin 10A0 to GND. During this period, the control circuit 530 scans the voltage levels of input / output pins IOB0-IOB3. During display period 639, the control circuit 530 sets the voltage level of input / output pin 10A0 to GND and the voltage level of input / output pin 10B0 to VDD.

[0115] exist Figure 6DDuring display period 641, the control circuit 530 sets the voltage level of the input / output pin IOB0 to level GND and the voltage level of the input / output pin IOA0 to level VDD. Therefore, the display device 510 presents a corresponding image based on the voltages of the input / output pins IOA0 and IOB0. During sensing period 642, the control circuit 530 sets the voltage level of the input / output pin IOB0 to level VDD (or a second predetermined level) and scans the voltage levels of the input / output pins IOA0-IOA3. During display period 643, the control circuit 530 again sets the voltage level of the input / output pin IOB0 to level GND and sets the voltage level of the input / output pin IOA0 to level VDD.

[0116] During display period 644, the control circuit 530 sets the voltage level of input / output pin IOB0 to level VDD and the voltage level of input / output pin IOA0 to level GND. During sensing period 645, the control circuit 530 sets the voltage level of input / output pin IOB0 to level VDD. During this period, the control circuit 530 scans the voltage levels of input / output pins IOA0-IOA3. During display period 646, the control circuit 530 sets the voltage level of input / output pin IOB0 to level VDD and the voltage level of input / output pin IOA0 to level GND.

[0117] During display period 647, the control circuit 530 sets the voltage level of input / output pin IOB0 to level VDD and the voltage level of input / output pin IOA0 to level GND. During sensing period 648, the control circuit 530 sets the voltage level of input / output pin IOB0 to level VDD. During this period, the control circuit 530 scans the voltage levels of input / output pins IOA0-IOA3. During display period 649, the control circuit 530 sets the voltage level of input / output pin IOB0 to level VDD and the voltage level of input / output pin IOA0 to level GND.

[0118] Figure 7Schematic diagram of the control circuit 530 of the present invention performing a sensing operation. First, set each pin of the first pin group to a first preset level (step S711). Then, scan the voltage level of each pin of the second pin group (step S712). Next, determine whether all pins of the second pin group have been scanned (step S713). If the scan has not been completed, return to step S712. If all pins of the second pin group have been scanned, execute step S714. Step S714 sets each pin of the second pin group to a second preset level. Then, scan the voltage level of each pin of the first pin group (step S715). Next, determine whether the voltage levels of all pins of the first pin group have been scanned (step S716). If the scan has not been completed, return to step S715. If the voltage levels of all pins of the first pin group have been scanned, the sensing operation ends.

[0119] In one embodiment, the second preset level in step S714 is relative to the first preset level in step S711. For example, when the first preset level is a high level, the second preset level is a low level. When the first preset level is a low level, the second preset level is a high level. In some embodiments, the first preset level in step S711 and the second preset level in step S714 are both equal to a floating level. For example, step S711 may not apply any voltage to the first pin group, and step S714 may not apply any voltage to the second pin group.

[0120] In other embodiments, steps S714 to S716 are executed earlier than step S711. In this example, the control circuit 530 first sets the voltage level of each pin of the second pin group to the second predetermined level, then scans the voltage levels of the pins of the first pin group. After scanning the voltage levels of all pins of the first pin group, the control circuit 530 sets the voltage level of each pin of the first pin group to the first predetermined level, and then scans the voltage level of each pin of the second pin group.

[0121] Figure 8A This is a possible schematic diagram of a display area according to the present invention. In this embodiment, display area 800A includes a plurality of light-emitting diodes (LEDs). Each LED is coupled to one of input pins SEG0-SEG3 and one of input pins COM0-COM3. Taking LED 810 as an example, the anode of LED 810 is coupled to input pin SEG0, and the cathode of LED 810 is coupled to input pin COM0. In this example, when the voltage difference between input pins SEG0 and COM0 is greater than the turn-on voltage of LED 810, LED 810 is illuminated. When the voltage difference between input pins SEG0 and COM0 is less than the turn-on voltage of LED 810, LED 810 is not illuminated.

[0122] During the sensing period, since the input pins COM0-COM3 may be at a high level (or the second predetermined level), even if the input pins SEG0-SEG3 receive a small voltage, the light-emitting diode 810 will not be turned on. Furthermore, since the input pins SEG0-SEG3 may be at a low level (or the first predetermined level), even if the input pins COM0-COM3 receive a small voltage, the light-emitting diode 810 will not be turned on. Therefore, during the sensing period, when the control circuit 530 performs a sensing operation on the capacitive touch device 520, the display device 510 will not be disturbed by the sensing operation.

[0123] Figure 8B This is another possible schematic diagram of the display area of ​​the present invention. In this embodiment, display area 800B includes a plurality of liquid crystal capacitors. Each liquid crystal capacitor is coupled to one of input pins SEG0-SEG3 and one of input pins COM0-COM3. Taking liquid crystal capacitor 820 as an example, liquid crystal capacitor 820 is coupled between input pins SEG0 and COM0.

[0124] During the sensing period, since the voltage level of the input pins COM0-COM3 may be equal to a floating level, even if the input pins SEG0-SEG3 receive a small voltage, the capacitor 820 will not be charged. Furthermore, since the voltage level of the input pins SEG0-SEG3 may be equal to a floating level, even if the input pins COM0-COM3 receive a small voltage, the capacitor 820 will not be charged. Therefore, during the sensing period, when the control capacitor 530 performs a sensing operation on the capacitive touch device 520, the sensing operation does not interfere with the display device 510.

[0125] Figure 9 FIG. 9 is a possible schematic diagram of a control circuit of the present invention. As shown in the figure, the control circuit 900 includes a display controller 910, a sensing circuit 920, and a transmission circuit 930. The display controller 910 is used to provide driving signals SSG0, SCM0, and a switching signal SEL. In one embodiment, the driving signal SSG0 is a segment signal, and the driving signal SCM0 is a common signal. In other embodiments, the display controller 910 integrates Figure 1 The image driver 131 and the micro control circuit 132 are configured as follows. In this example, the driving signal SSG0 serves as one of the driving signals SD1-SD4, and the driving signal SCM0 serves as the other of the driving signals SD1-SD4.

[0126] The sensing circuit 920 provides a reference voltage DK and receives a sensing voltage V AN3 and V BN0 In one embodiment, the sensing voltage VAN3 is the voltage of the sensing pin AN3 of the capacitive touch device 520, the sensing voltage V BN0 is the voltage of the sensing pin BN0 of the capacitive touch device 520. In other embodiments, the sensing circuit 920 receives fewer or more sensing voltages, such as the voltages of the sensing pins AN0-AN2 and BN1-BN3 of the capacitive touch device 520. Figure 1 The characteristics of the sensing circuit 133 are similar, so they are not described again.

[0127] Transmission circuit 930 selects display controller 910 or sensing circuit 920 based on switching signal SEL, thereby providing the output of display controller 910 or sensing circuit 920 to input / output pins 10A0 and 10B0. During a display period, transmission circuit 930 provides drive signals SSG0 and SCM0 to input / output pins 10A0 and 10B0 based on switching signal SEL. During a sensing period, transmission circuit 930 provides reference voltage DK to one of input / output pins 10A0 and 10B0 based on switching signal SEL and sets the level of the other input / output pin 10A0 or 10B0.

[0128] Assume that I / O pin 10A0 belongs to the first pin group, and I / O pin 10B0 belongs to the second pin group. During a first sensing period, display controller 910 requests transmission circuit 930 to provide reference voltage DK to I / O pin 10A0 and drive signal SCM0 to I / O pin 10B0. At this time, drive signal SCM0 is equal to a first predetermined level. In other embodiments, display controller 910 may request transmission circuit 930 to stop transmitting any signal to I / O pin 10B0. In this example, the voltage level of I / O pin 10B0 is a floating level. In some embodiments, when transmission circuit 930 provides reference voltage DK to I / O pin 10A0, sensing circuit 920 provides a first predetermined level (e.g., a low level or a high level). In this example, transmission circuit 930 may transmit the first predetermined level provided by sensing circuit 920 to I / O pin 10B0.

[0129] During the second sensing period, the display controller 910 requests the transmission circuit 930 to provide a reference voltage DK to the I / O pin 10B0 and to provide a drive signal SSG0 to the I / O pin 10A0. At this time, the drive signal SSG0 is equal to a second predetermined level. In other embodiments, the display controller 910 may request the transmission circuit 930 to stop transmitting any signals to the I / O pin 10A0. In this example, the voltage level of the I / O pin 10A0 is a floating level. In some embodiments, when the transmission circuit 930 provides the reference voltage DK to the I / O pin 10B0, the sensing circuit 920 provides a second predetermined level (e.g., a high level or a low level). In this example, the transmission circuit 930 may transmit the second predetermined level provided by the sensing circuit 920 to the I / O pin 10A0.

[0130] After the transmission circuit 930 provides the reference voltage DK to the input / output pin 10A0, the sensing circuit 920 detects the voltage V AN3 In this example, when the voltage V AN3 When the voltage is not equal to the reference voltage DK, it indicates that the sensing area corresponding to the sensing pin AN3 of the capacitive touch device 520 is touched. Therefore, the sensing circuit 920 informs the display controller 910, so that the display controller 910 performs a corresponding action.

[0131] Similarly, after the transmission circuit 930 provides the reference voltage DK to the input / output pin IOB0, the sensing circuit 920 detects the voltage V BN0 In this example, when the voltage V BN0 When the voltage is not equal to the reference voltage DK, it indicates that the sensing area corresponding to the sensing pin BN0 of the capacitive touch device 520 is touched. Therefore, the sensing circuit 920 notifies the display controller 910, so that the display controller 910 performs another corresponding action.

[0132] Before detecting the voltage of the input / output pin 10A0 or 10B0, the sensing circuit 920 first provides a reference voltage DK to the input / output pin 10A0 or 10B0. Therefore, the sensing operation performed by the sensing circuit 920 is less susceptible to interference from noise.

[0133] For the convenience of explanation, Figure 9Only input / output pins IOA0 and IOB0 are shown, but this is not intended to limit the present invention. In other embodiments, transmission circuit 930 couples to more input / output pins (e.g., IOA1-IOA3, IOB1-IOB3). The present invention is not limited to the architecture of transmission circuit 930. In one embodiment, transmission circuit 930 includes switching circuits 931 and 932. Switching circuits 931 and 932 transmit corresponding signals based on a switching signal SEL. In other embodiments, display controller 910 provides two switching signals to control switching circuits 931 and 932.

[0134] In other embodiments, before the sensing circuit 920 performs a sensing operation to determine whether the capacitive touch device 520 is touched, the sensing circuit 920 may send a request signal (not shown) to the display controller 910. The display controller 910 responds to the sensing circuit 920 and sends an approval signal. During a specific period, the sensing circuit 920 may control the voltage levels of the input / output pins 10A0 and 10B0. After the specific period, the display controller 910 controls the voltage levels of the input / output pins 10A0 and 10B0.

[0135] During the sensing period, the control circuit 900 scans a portion of the input and output pins and sets another portion of the output pins to a preset level (such as a low level or a high level) or a floating level. Therefore, the display device 510 is not affected by the sensing operation of the control circuit 900 during the sensing period.

[0136] Furthermore, if the display device 510 is a passive matrix display, due to its slow response rate, even if the potential of the input / output pin changes, the passive matrix display will not immediately react. Therefore, even if the input / output pin is set to a reference voltage, the display device 510 will not be affected by the reference voltage. In other embodiments, even if the display device 510 is an active matrix display, because the reference voltage is lower than the level of the drive signal, the display device 510 will not be affected by the reference voltage. In some embodiments, the sensing period is shorter than the display period, so the display device 510 will not be affected by the sensing operation.

[0137] Unless otherwise defined, all terms (including technical and scientific terms) used herein are those generally understood by those skilled in the art to which this invention belongs. Furthermore, unless otherwise expressly stated, dictionary definitions of terms should be interpreted as consistent with their meanings in the relevant technical context and should not be interpreted as idealized or overly formal.

[0138] While the present invention has been disclosed above with reference to preferred embodiments, these are not intended to limit the present invention. Any person skilled in the art may make modifications and variations without departing from the scope of the present invention. For example, the systems, devices, or methods of the present invention may be implemented as physical embodiments using hardware, software, or a combination of hardware and software.

Claims

1. A control circuit, characterized in that: include: a first input-output pin for coupling to a first input pin of a display device and a first sensing pin of a capacitive touch device; a second input-output pin, configured to couple a second input pin of the display device and a second sensing pin of the capacitive touch device; a sensing circuit for determining whether the capacitive touch device is touched based on the voltages of the first input / output pin and the second input / output pin; as well as a display controller, during a display period, providing a first driving signal to the display device through the first input / output pin, and providing a second driving signal to the display device through the second input / output pin, in: During a first sensing period, the first input / output pin is equal to a first preset level, and the sensing circuit detects the voltage of the second input / output pin. The control circuit controls the first preset level to be equal to a first floating level.

2. The control circuit according to claim 1, wherein: During the first sensing period, the display controller sets the first input / output pin to be equal to the first preset level.

3. The control circuit according to claim 1, wherein: During the first sensing period, the sensing circuit sets the first input / output pin to be equal to the first preset level.

4. The control circuit according to claim 3, characterized in that: During a second sensing period, the sensing circuit sets the second input / output pin to a second preset level and detects the voltage of the first input / output pin.

5. The control circuit according to claim 4, characterized in that: When the first preset level is a high level, the second preset level is a low level; when the first preset level is a low level, the second preset level is a high level.

6. The control circuit according to claim 4, characterized in that: The second preset level is equal to a second floating level.

7. The control circuit according to claim 1, wherein: The sensing circuit includes: a comparator having a non-inverting input terminal, an inverting input terminal, and an output terminal, wherein the inverting input terminal is coupled to the first input-output pin; a first capacitor coupled between a specific node and the non-inverting input terminal; a second capacitor coupled between the specific node and the inverting input terminal; and A controller controls the voltage of the specific node and adjusts the capacitance of the second capacitor according to the voltages of the non-inverting input terminal and the inverting input terminal.

8. A display device, characterized in that: include: A display device having a first input pin and a second input pin; A capacitive touch device having a first sensing pin and a second sensing pin; as well as A control circuit comprising: a first input-output pin coupled to the first input pin and the first sensing pin; a second input-output pin coupled to the second input pin and the second sensing pin; a sensing circuit for determining whether the capacitive touch device is touched according to the voltages of the first input / output pin and the second input / output pin; and a display controller, during a display period, providing a first driving signal to the display device through the first input / output pin, and providing a second driving signal to the display device through the second input / output pin, in: During a first sensing period, the sensing circuit sets the first input / output pin to a first preset level and detects the voltage of the second input / output pin. The control circuit controls the first preset level to be equal to a first floating level.

9. The display device according to claim 8, wherein The display device is a passive matrix display.

10. The display device according to claim 8, wherein During a first sensing period, the sensing circuit first provides a reference voltage to the second input / output pin and then detects the voltage of the second input / output pin. The reference voltage is one-third or one-quarter of the first driving signal.

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