Short circuit test circuit, touch sampling circuit and display device

Abstract

Embodiments of the present application provide a short-circuit test circuit, a touch sampling circuit and a display device. The short-circuit test circuit comprises a first switch unit, a second switch unit and a charge conversion unit. The short-circuit test circuit is used for, for two touch points, if the first switch unit and the second switch unit corresponding to one touch point receive a first level, a first voltage signal at an output end of the charge conversion unit corresponding to the touch point becomes smaller, the first switch unit and the second switch unit corresponding to another touch point receive a second level, the first voltage signal at the output end of the charge conversion unit corresponding to the touch point becomes larger, and then the two touch points do not have a short circuit. Embodiments of the present application can realize batch detection of short-circuit conditions of touch points, and realize short-circuit detection of all touch points, so as to shorten the test time and reduce the test cost.

Description

Technical Field

[0001] This application relates to the field of touch technology, and more specifically, to a short-circuit test circuit, a touch sampling circuit, and a display device. Background Technology

[0002] Currently, touch point short circuit testing generally adopts the single-point short circuit testing principle, that is, testing each touch point one by one. For example, in the mass production process, there are 100,000 chips, each chip has 40*60 touch points, and the testing time for each touch point is 1ms, then the total testing time is 100,000*40*60*1ms=240,000s=66 hours.

[0003] Therefore, using the existing single-point short-circuit test principle requires a long testing time and has a high testing cost. Summary of the Invention

[0004] This application addresses the shortcomings of existing methods by proposing a short-circuit test circuit, a touch sampling circuit, and a display device to solve the technical problems of long test times or high test costs in the prior art.

[0005] In a first aspect, embodiments of this application provide a short-circuit test circuit for electrical connection to a touch point, comprising: a first switching unit, a second switching unit, and a charge conversion unit; The first terminal and the control terminal of the first switching unit are used to receive a preset voltage and a control signal, respectively; the first terminal and the control terminal of the second switching unit are used to ground and receive a control signal, respectively; the control signal includes a first level and a second level. The first input terminal of the charge conversion unit is electrically connected to the second terminal of both the first and second switching units. The first and second input terminals of the charge conversion unit are used to receive the charge conversion signal and the excitation voltage signal, respectively, and the output terminal of the charge conversion unit is used to output the first voltage signal. The charge conversion signal is obtained based on the parasitic capacitance of the touch point, and the first voltage signal is obtained by converting the charge conversion signal based on the excitation voltage signal. The short-circuit test circuit is used for two touch points. If the first and second switching units corresponding to one touch point receive a first level, the first switching unit is turned on and the second switching unit is turned off, and the first voltage signal at the output terminal of the charge conversion unit corresponding to that touch point decreases, and the first and second switching units corresponding to the other touch point receive a second level, the first switching unit is turned off and the second switching unit is turned on, and the first voltage signal at the output terminal of the charge conversion unit corresponding to that touch point increases, then the two touch points are not short-circuited. The two touch points are one touch point in each of any two rows of touch points, and the control signal received by the short-circuit test circuit corresponding to each row of touch points is the same.

[0006] In one possible implementation, the short-circuit test circuit is also used to test two touch points. If the first and second switching units corresponding to one touch point receive a first level, the first switching unit is turned on and the second switching unit is turned off. If the first and second switching units corresponding to the other touch point receive a second level, the first switching unit is turned off and the second switching unit is turned on. If the first voltage signal at the output terminal of the charge conversion unit corresponding to both touch points remains unchanged, then the two touch points are short-circuited.

[0007] In one possible implementation, the short-circuit test circuit further includes: The control unit is electrically connected to the control terminal of the first switch unit and the control terminal of the second switch unit, and is used to output control signals to the first switch unit and the second switch unit corresponding to each touch point, so that the short circuit test circuit corresponding to the two touch points can respectively receive the first level and the second level. Among them, the control signals corresponding to each row of touch points form a set of level sequences. The control unit outputs multiple sets of level sequences to each row of touch points. Each set of level sequences is formed by combining the first level and the second level in a preset order. In one possible implementation, the first switching unit includes a first switching module and a second switching module; The first end of the first switch module and the second end of the second switch module serve as the first end and the second end of the first switch unit, respectively, and the control end of the second switch module serves as the control end of the first switch unit. The control terminal and the second terminal of the first switch module are electrically connected to the first terminal of the second switch module.

[0008] In one possible implementation, the second switching unit includes a third switching module and a fourth switching module; The first end of the third switch module and the second end of the fourth switch module serve as the first end and the second end of the second switch unit, respectively, and the control end of the fourth switch module serves as the control end of the second switch unit. The control terminal and the second terminal of the third switch module are electrically connected to the first terminal of the fourth switch module.

[0009] In one possible implementation, the charge conversion unit includes: a charge amplifier, a reset capacitor, and a reset control switch; The first input terminal, the second input terminal, and the output terminal of the charge amplifier serve as the first input terminal, the second input terminal, and the output terminal of the charge conversion unit, respectively. The first and second terminals of the reset capacitor are electrically connected to the first input terminal and the output terminal of the charge amplifier, respectively. The first and second terminals of the reset control switch are electrically connected to the first input terminal and the output terminal of the charge amplifier, respectively. The control terminal of the reset control switch is used to receive the reset control signal to control the switching on and off.

[0010] In one possible implementation, the charge conversion unit further includes: a first capacitor; The first terminal of the first capacitor is electrically connected to the first input terminal of the charge amplifier; The second terminal of the first capacitor is used to receive the excitation voltage signal.

[0011] Secondly, embodiments of this application provide a touch sampling circuit, including: a signal processing circuit and a short-circuit test circuit as described in the first aspect; The signal processing circuit is electrically connected to the output terminal of the charge conversion unit and is used to set and process the first voltage signal and output a digital signal. The digital signal is used to represent the voltage amplitude change of the first voltage signal to determine whether the touch point is short-circuited.

[0012] In one possible implementation, the signal processing circuit includes a third switching unit and a sampling unit; The first terminal of the third switching unit is electrically connected to the output terminal of the charge conversion unit; The second and third terminals of the third switching unit are used to receive the first reference signal and the second reference signal, respectively. The fourth and fifth terminals of the third switching unit are electrically connected to the first and second terminals of the sampling unit, respectively. The first reference signal and the second reference signal correspond to the low level and high level of the excitation voltage signal, respectively. The sampling unit is configured to output a first set of differential signals from the third and fourth terminals of the sampling unit based on the first voltage signal and the first reference signal when the first voltage signal is low, the first and fifth terminals of the third switching unit are turned on, and the second and fourth terminals are turned on; and to output a second set of differential signals from the third and fourth terminals of the sampling unit based on the first voltage signal and the second reference signal when the first voltage signal is high, the first and fourth terminals of the third switching unit are turned on, and the third and fifth terminals are turned on. Among them, the low level and the high level are the first voltage signal that decreases to zero and the first voltage signal that increases to a preset voltage, respectively; the digital signal is determined by comparing the first group of differential signals or by comparing the second group of differential signals. In one possible implementation, the signal processing circuit further includes: a signal conversion unit; The first and second input terminals of the signal conversion unit are used to electrically connect to the third and fourth terminals of the sampling unit, respectively. The signal conversion unit is used to compare the first set of differential signals or the second set of differential signals, obtain the comparison result, and convert the comparison result into a digital signal for output.

[0013] Thirdly, embodiments of this application provide a display device, including a touch panel, and a short-circuit test circuit as described in the first aspect or a touch sampling circuit as described in the second aspect; The touch panel includes multiple touch points, each of which is electrically connected to the first input terminal of a charge conversion unit.

[0014] The beneficial technical effects of the technical solutions provided in this application include: In this embodiment of the short-circuit test circuit, the first and second switching units receive a first level in the control signal. The first switching unit is turned on and the second switching unit is turned off. Since the control signal received by the short-circuit test circuit corresponding to each row of touch points is the same, the first terminal of the first switching unit receives a preset voltage. At the current row of touch points, this is equivalent to connecting an upward current, causing the first voltage signal at the output terminal of the charge conversion unit to decrease. Then, the first and second switching units receive a second level in the control signal. The first switching unit is turned off and the second switching unit is turned on. The first terminal of the second switching unit is grounded, and at the current row of touch points, this is equivalent to connecting a downward current, causing the first voltage signal at the output terminal of the charge conversion unit to increase. Under normal operation, the first voltage signal at the output terminal of the charge conversion unit in this embodiment of the short-circuit test circuit will change, thus confirming that the touch point is not short-circuited.

[0015] Based on the circuit structure of the short-circuit test circuit in this application embodiment, it is possible to determine whether two touch points are short-circuited. The short-circuit test circuits corresponding to the two touch points receive a first level and a second level, respectively. That is, the first and second switching units corresponding to one touch point receive the first level, and the first and second switching units corresponding to the other touch point receive the second level. In the absence of a short circuit, a pull-up current is connected to the row containing one touch point, and a pull-down current is connected to the row containing the other touch point. This causes the first voltage signal at the output of the charge conversion unit to increase or decrease. Based on the change in the first voltage signal, it can be determined whether the two touch points are short-circuited. Furthermore, since the control signal received by the short-circuit test circuits corresponding to each row of touch points is the same, batch detection of short circuits in touch points can be achieved. Moreover, as long as the two rows of touch points correspond to the first and second levels respectively, short-circuit detection of all touch points can be achieved in batches, thereby shortening the test time, greatly improving test efficiency, increasing test reliability, and ultimately reducing test costs.

[0016] Additional aspects and advantages of this application will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of this application. Attached Figure Description

[0017] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a schematic diagram of a short-circuit test circuit provided in an embodiment of this application; Figure 2 A schematic diagram of a touch point and parasitic capacitance at the touch point provided in an embodiment of this application; Figure 3 This is a schematic diagram of another short-circuit test circuit provided in an embodiment of this application; Figure 4 This is a schematic diagram illustrating a control unit outputting control signals to each row of touch points, provided in an embodiment of this application. Figure 5 A schematic diagram of another short-circuit test circuit provided in the embodiments of this application; Figure 6 For the embodiments of this application, CTRL[n] is the first voltage signal V connected to the touch point SV[n] when it is low. CA A timeline diagram of the changes; Figure 7 This is a schematic diagram of the structure of a touch sampling circuit provided in an embodiment of this application; Figure 8 This is a schematic diagram of a touch sampling circuit electrically connected to a touch point, provided as an embodiment of this application.

[0018] Figure label: 10-Touch sampling circuit; 100 - Short-circuit test circuit; 110 - First switching unit; 111 - First switching module; 112 - Second switching module; 120 - Second switching unit; 121 - Third switching module; 122 - Fourth switching module; 130 - Charge conversion unit; 131 - Charge amplifier; 132 - Reset capacitor; 133 - Reset control switch; 134 - First capacitor; 140 - Control unit; 200 - Signal processing circuit; 210 - Third switching unit; 211 - First control switch; 212 - Second control switch; 213 - Third control switch; 214 - Fourth control switch; 220 - Sampling unit; 221 - First sampling capacitor; 222 - Second sampling capacitor; 223 - Sampling amplifier; 224 - First holding capacitor; 225 - Second holding capacitor; 230 - Signal conversion unit; 300 - touch points, 310 - parasitic capacitance. Detailed Implementation

[0019] This application is described in detail below. Examples of embodiments of this application are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. Furthermore, detailed descriptions of known technologies that are unnecessary for the features of this application are omitted. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0020] Those skilled in the art will understand that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0021] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this application means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or wireless coupling. The term “and / or” as used herein includes all or any units and all combinations of one or more associated listed items.

[0022] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments.

[0023] This application provides a short-circuit test circuit; see [link to relevant documentation]. Figure 1 and Figure 2 As shown, the short-circuit test circuit 100 is used for electrical connection with a touch point 300. See also Figure 1 As shown, the short-circuit test circuit 100 includes: a first switching unit 110, a second switching unit 120, and a charge conversion unit 130.

[0024] The first terminal and the control terminal of the first switching unit 110 are used to receive a preset voltage and a control signal, respectively; the first terminal and the control terminal of the second switching unit 120 are used to ground and receive a control signal, respectively; the control signal includes a first level and a second level.

[0025] The first input terminal of the charge conversion unit 130 is electrically connected to the second terminal of the first switching unit 110 and the second terminal of the second switching unit 120.

[0026] The first input terminal and the second input terminal of the charge conversion unit 130 are used to receive the charge conversion signal and the excitation voltage signal, respectively. The output terminal of the charge conversion unit 130 is used to output the first voltage signal. The charge conversion signal is obtained based on the parasitic capacitance 310 of the touch point 300, and the first voltage signal is obtained by converting the charge conversion signal based on the excitation voltage signal.

[0027] The short-circuit test circuit 100 is used to test two touch points 300. If the first switch unit 110 and the second switch unit 120 corresponding to one touch point 300 receive a first level, the first switch unit 110 is turned on and the second switch unit 120 is turned off, and the first voltage signal at the output terminal of the charge conversion unit 130 corresponding to that touch point 300 decreases, and the first switch unit 110 and the second switch unit 120 corresponding to the other touch point 300 receive a second level, the first switch unit 110 is turned off and the second switch unit 120 is turned on, and the first voltage signal at the output terminal of the charge conversion unit 130 corresponding to that touch point 300 increases, then the two touch points 300 are not short-circuited. The two touch points 300 are one touch point 300 in each of any two rows of touch points 300, and the control signal received by the short-circuit test circuit 100 corresponding to each row of touch points 300 is the same.

[0028] like Figure 1 As shown, VDD is the preset voltage, CTRL[n+i] is the control signal for inputting touch point 300 in this row, Vex represents the excitation voltage signal, and V CA This represents the first voltage signal, V. I This indicates a charge conversion signal.

[0029] Optionally, the control terminals of both the first switching unit 110 and the second switching unit 120 can be input with a first level and a second level. If the first level is low, the second level is high; if the first level is high, the second level is low. This embodiment uses a first level low and a second level high as an example for illustration. High level is 1, low level is 0, and CTRL[n+i] is 0 or 1.

[0030] In this embodiment, the conduction of the first switching unit 110 and the second switching unit 120 is based on opposite voltage levels. That is, when one of the first switching unit 110 and the second switching unit 120 is on, the other is off. The conduction of the first switching unit 110 means that the control terminal of the first switching unit 110 receives a first voltage level, and the first and second terminals of the first switching unit 110 are connected; the conduction of the second switching unit 120 means that the control terminal of the second switching unit 120 receives a second voltage level, and the first and second terminals of the second switching unit 120 are connected.

[0031] Optionally, the preset voltage VDD can be selected as a positive voltage according to the actual situation, so that when the first terminal and the second terminal of the first switching unit 110 are turned on, a pull-up current can be formed between the first terminal of the first switching unit 110 and the first input terminal of the charge conversion unit 130. That is, it is equivalent to connecting a pull-up current to the row where the touch point 300 is located, so that the first voltage signal V at the output terminal of the charge conversion unit 130 is generated. CA The value decreases. The preset voltage VDD can range from 2.7V to 3.6V.

[0032] Optionally, the first terminal of the second switching unit 120 is grounded (voltage is 0), so that when the first and second terminals of the second switching unit 120 are connected, a pull-down current can be formed between the first terminal of the second switching unit 120 and the first input terminal of the charge conversion unit 130. That is, it is equivalent to connecting a pull-down current to the row where the touch point 300 is located, so that the first voltage signal V at the output terminal of the charge conversion unit 130 is... CA It gets bigger.

[0033] Optionally, when the first switching unit 110 and the second switching unit 120 are turned on, they act as pull-up and pull-down circuits, respectively, enabling the first voltage signal V at the output terminal of the charge conversion unit 130 to... CA Changes are observed to determine whether touch point 300 is short-circuited.

[0034] In this embodiment, the first voltage signal V CA After being enlarged, it becomes the preset voltage VDD, the first voltage signal V. CA It becomes zero after being reduced to a smaller value.

[0035] See Figure 2 The diagram shows a schematic of the structure of the touch front end connected to the short-circuit test circuit 100, where a parasitic capacitance 310 (capacitance Cp) is formed at the touch point 300.

[0036] Optionally, the charge conversion unit 130 can adopt a circuit structure similar to a charge amplifier already existing in the touch panel, which can convert the charge corresponding to the charge at the touch point 300 into a charge conversion signal V. I Converted into the first voltage signal V CAAmong them, the excitation voltage signal Vex is a series of electrical signals input into the circuit to observe the characteristics of a circuit system. The excitation voltage signal Vex is also called the protection signal, which can effectively eliminate the negative impact of parasitic capacitance 310 on the size of the touch capacitor.

[0037] In this embodiment of the short-circuit test circuit 100, the first switching unit 110 and the second switching unit 120 receive a first level in the control signal. The first switching unit 110 is turned on and the second switching unit 120 is turned off. Since the control signal received by the short-circuit test circuit 100 corresponding to each row of touch points 300 is the same, the first terminal of the first switching unit 110 receives a preset voltage. At the current row of touch points 300, this is equivalent to connecting an upward current, causing the first voltage signal at the output terminal of the charge conversion unit 130 to decrease. Then, the first switching unit 110 and the second switching unit 120 receive a second level in the control signal. The first switching unit 110 is turned off and the second switching unit 120 is turned on. The first terminal of the second switching unit 120 is grounded, and at the current row of touch points 300, this is equivalent to connecting a downward current, causing the first voltage signal at the output terminal of the charge conversion unit 130 to increase. Under normal operation, the first voltage signal at the output terminal of the charge conversion unit 130 will change, thus confirming that the touch point 300 is not short-circuited.

[0038] Based on the circuit structure of the short-circuit test circuit 100 in the embodiments of this application, it is possible to determine whether two touch points 300 are short-circuited. The short-circuit test circuit 100 corresponding to the two touch points 300 respectively receives a first level and a second level. That is, the first switch unit 110 and the second switch unit 120 corresponding to one touch point 300 receive the first level, and the first switch unit 110 and the second switch unit 120 corresponding to the other touch point 300 receive the second level. In the absence of a short circuit, the row where one touch point 300 is located is connected to an upward pull-up current, and the row where the other touch point 300 is located is connected to a downward pull-down current. In this way, the first voltage signal at the output terminal of the charge conversion unit 130 will increase or decrease. Based on the change in the first voltage signal, it can be determined whether the two touch points 300 are short-circuited. Meanwhile, since the control signals received by the short-circuit test circuit 100 corresponding to each row of touch points 300 are the same, the short-circuit condition of touch points 300 can be detected in batches. Moreover, as long as the two rows of touch points 300 correspond to the first level and the second level respectively, the short-circuit detection of all touch points 300 can be realized in batches, thereby shortening the test time, greatly improving the test efficiency, improving the test reliability, and thus reducing the test cost.

[0039] In some embodiments, the short-circuit test circuit 100 is further configured to, for two touch points 300, if the first switching unit 110 and the second switching unit 120 corresponding to one touch point 300 receive a first level, the first switching unit 110 is turned on and the second switching unit 120 is turned off, and the first switching unit 110 and the second switching unit 120 corresponding to the other touch point 300 receive a second level, the first switching unit 110 is turned off and the second switching unit 120 is turned on, and the first voltage signal at the output terminal of the charge conversion unit 130 corresponding to both touch points 300 remains unchanged, then the two touch points 300 are short-circuited.

[0040] In this embodiment, when two touch points 300 are short-circuited, one touch point 300 is equivalent to forming an upward current and the other touch point 300 is equivalent to forming a downward current. The upward current and the downward current are basically equal, which means that the voltage of the two short-circuited touch points 300 is consistent with that during normal sampling, that is, the first voltage signal at the output of the charge conversion unit 130 remains almost unchanged, which is equivalent to the intermediate level.

[0041] In some embodiments, see Figure 3 As shown, the short-circuit test circuit 100 further includes a control unit 140. The control unit 140 is electrically connected to the control terminal of the first switch unit 110 and the control terminal of the second switch unit 120, and is used to output control signals to the first switch unit 110 and the second switch unit 120 corresponding to each touch point 300, so that the short-circuit test circuit 100 corresponding to the two touch points 300 respectively receives a first level and a second level.

[0042] Among them, the control signals corresponding to each row of touch points 300 form a set of level sequences, and the control unit 140 outputs multiple sets of level sequences to each row of touch points 300. Each set of level sequences is formed by combining the first level and the second level in a preset order.

[0043] Optionally, the control unit 140 can be a logic control circuit, which can output multiple sets of level sequences in sequence to ensure that between any two rows of touch points 300, one row of touch points 300 is connected to the first level and the other row of touch points 300 is connected to the second level, thereby enabling short-circuit testing of all touch points 300 and improving test reliability.

[0044] See Figure 4As shown, in this embodiment of the application, the control unit 140 sequentially inputs multiple sets of level sequences to each row of touch points 300, such as: 101010 (odd and even) combination, 11001100 combination, 111000111000 combination, etc. That is, multiple sets of level sequences can be a cycle of one 1 + one 0 (odd and even cycle), two sets of 1 + two sets of 0 cycle, three sets of 1 + three sets of 0 cycle, four sets of 1 + four sets of 0 cycle, etc., until short circuit detection of touch points 300 covering the entire touch panel is achieved.

[0045] Those skilled in the art will recognize that the multiple combinations listed in the examples in this application include, but are not limited to, 101010, 110011001100, 111000111000, 11110000, etc. Other combinations that can achieve the goal of detecting all 300 touch points without missing any and save testing time are all within the scope of protection of this application.

[0046] See Figure 4 As shown, research revealed that if the two short-circuited touch points 300 occur between SV[n] and SV[n+1], or between SV[m] and SV[m+1], then by applying pull-up current to odd-numbered rows and pull-down current to even-numbered rows (i.e., a 101010 (odd-even) combination), the short-circuited touch point 300 can be quickly detected. However, if the touch point 300 occurs between SV[n+1] and SV[x], or between SV[y] and SV[z], then the 101010 (odd-even) combination cannot detect where the short circuit is. This is because if a short circuit occurs between SV[n+1] and SV[x], then both SV[n+1] and SV[x] are in even-numbered rows, and the control signal will apply pull-down current to both SV[n+1] and SV[x]. Therefore, even if the two touch points 300 are short-circuited, they are both pulled to a low level, and the intermediate level indicating a short-circuit anomaly will not appear. Thus, the odd-even short-circuit test method fails.

[0047] Similarly, if a short circuit occurs between SV[y] and SV[z], then both SV[y] and SV[z] will be in odd-numbered rows, and the control signal will apply pull-up current to both SV[y] and SV[z]. Therefore, even if there is a short circuit, they will both be pulled to a high level, and there will be no intermediate level indicating a short circuit abnormality. Thus, the odd-even short circuit test method also fails.

[0048] Based on the above analysis, the embodiments of this application employ multiple sets of level sequences, for example... Figure 4The "1" and "0" displayed represent whether the control signal CTRL[n+i] (i=…,-2,-1,0,1,2,…) of the touch point 300 where the row is located is high or low. When the "CTRL[n]" signal is "0" (low level), the current row is connected to a pull-up current; when the "CTRL[n]" signal is "1" (high level), the current row is connected to a pull-down current. When the "CTRL[n+1]" signal is "0" (low level), the current row is connected to a pull-up current; when the "CTRL[n+1]" signal is "1" (high level), the current row is connected to a pull-down current, and so on.

[0049] This embodiment uses multiple sets of level sequences to ensure that between any two rows of touch points 300, one row of touch points 300 is connected to 0 and the other row is connected to 1, thus enabling the detection of short circuits in all touch points 300. Unlike the standard method of judging by current anomalies, this embodiment primarily uses internal circuit multiplexing to perform batch short circuit detection of touch points 300. Furthermore, this embodiment employs multiple sets of row control scanning methods to perform different current pull-up and pull-down detection methods, specifically performing short circuit testing horizontally in rows CTRL[n+i] (i=…,-2,-1,0,1,2,…).

[0050] If 300 touch points on the entire touch panel require 10 combinations to ensure that every short circuit condition can be identified, then using the multi-combination short circuit testing method proposed in this application, only 10 sets of test times are needed to batch detect all touch point short circuit conditions, with a total test time of 100000 * 1 * 1 * 10 ms = 1000 s = 0.27 hours. An odd-even short circuit test scheme in a chip mass production stage requires 100 seconds, but may miss some touch point short circuit conditions. In contrast, a multi-combination short circuit test scheme in a chip mass production stage requires 1000 seconds and can identify all short circuit conditions, greatly improving test efficiency, increasing test reliability, and reducing test time costs.

[0051] In some embodiments, see Figure 5 As shown, the first switching unit 110 includes a first switching module 111 and a second switching module 112. The first end of the first switching module 111 and the second end of the second switching module 112 serve as the first end and the second end of the first switching unit 110, respectively, and the control end of the second switching module 112 serves as the control end of the first switching unit 110. The control end and the second end of the first switching module 111 are electrically connected to the first end of the second switching module 112.

[0052] In some embodiments, see Figure 5As shown, the second switch unit 120 includes a third switch module 121 and a fourth switch module 122; the first end of the third switch module 121 and the second end of the fourth switch module 122 serve as the first end and the second end of the second switch unit 120, respectively, and the control end of the fourth switch module 122 serves as the control end of the second switch unit 120; the control end and the second end of the third switch module 121 are electrically connected to the first end of the fourth switch module 122.

[0053] Optionally, the first switch module 111, the second switch module 112, the third switch module 121, and the fourth switch module 122 each include a switching device. The first switch module 111 and the second switch module 112 include switching devices that are simultaneously turned on, and the third switch module 121 and the fourth switch module 122 include switching devices that are simultaneously turned on. The second switch module 112 and the fourth switch module 122 are used to control the on and off states, while the switching devices of the first switch module 111 and the third switch module 121 are used to provide current.

[0054] As an example, see Figure 5 As shown, the first switch module 111 includes a switch device MP1, the second switch module 112 includes a switch device SW1, the third switch module 121 includes a switch device MP2, and the fourth switch module 122 includes a switch device SW2.

[0055] In this embodiment, switching devices MP1 and SW1 can be PMOS, and switching devices MP2 and SW2 can be NMOS. It is understood that switching devices MP1 and SW1 can be NMOS, and switching devices MP2 and SW2 can be PMOS.

[0056] Specifically, the source, drain, and gate of switching device MP1 serve as the first terminal, second terminal, and control terminal of the first switching module 111, respectively; the source, drain, and gate of switching device SW1 serve as the first terminal, second terminal, and control terminal of the second switching module 112, respectively; the source, drain, and gate of switching device MP2 serve as the first terminal, second terminal, and control terminal of the third switching module 121, respectively; and the source, drain, and gate of switching device SW2 serve as the first terminal, second terminal, and control terminal of the fourth switching module 122, respectively.

[0057] In some embodiments, see Figure 5 As shown, the charge conversion unit 130 includes: a charge amplifier 131, a reset capacitor 132, and a reset control switch 133.

[0058] The first input terminal, the second input terminal, and the output terminal of the charge amplifier 131 serve as the first input terminal, the second input terminal, and the output terminal of the charge conversion unit 130, respectively.

[0059] The first and second terminals of the reset capacitor 132 are electrically connected to the first input terminal and the output terminal of the charge amplifier 131, respectively.

[0060] The first and second terminals of the reset control switch 133 are electrically connected to the first input terminal and the output terminal of the charge amplifier 131, respectively.

[0061] The control terminal of the reset control switch 133 is used to receive a reset control signal to control the on and off states of the reset control switch 133.

[0062] Optionally, the control terminal of the reset control switch 133 can also be electrically connected to the control unit 140, and the control unit 140 outputs a reset control signal to control the on and off of the reset control switch 133.

[0063] In some embodiments, see Figure 5 As shown, the charge conversion unit 130 further includes: a first capacitor 134; the first end of the first capacitor 134 is electrically connected to the first input end of the charge amplifier 131; the second end of the first capacitor 134 is used to receive the excitation voltage signal.

[0064] As an example, see Figure 5 As shown, Ccancle represents the first capacitor 134, Vcancle represents the voltage signal received at the second terminal of the first capacitor 134, Vcancle is the excitation voltage signal Vex, CA represents the charge amplifier 131, Cfb represents the reset capacitor 132, and reset represents the reset control switch 133. The charge conversion signal V... I Connected to the inverting input of charge amplifier 131, the charge conversion signal V I The first terminal of capacitor Ccancel is electrically connected. The positive input terminal of charge amplifier 131 receives the excitation voltage signal Vex. A reset capacitor 132 and a reset control switch 133 are connected between the inverting input terminal and the output terminal of charge amplifier 131.

[0065] Optionally, the excitation voltage signal Vex is a rectangular wave signal with high and low levels. When the short-circuit test circuit 100 does not generate a pull-up or pull-down current, or the pull-up and pull-down currents cancel each other out, the first voltage signal V at the output of the charge amplifier 131... CA It is a level signal that corresponds to the high-level and low-level phases of the excitation voltage signal Vex.

[0066] See Figure 5As shown, each touch point 300 is connected to a charge amplifier 131. That is, with 120 touch points 300, the chip itself is designed with 120 short-circuit test circuits 100, and the charge conversion signal V... I There will also be 120. When performing short-circuit tests in batches, the CTRL[n] row containing SV[n] is controlled by the CTRL[n] signal. The VI[n] signal connected to SV[n] is given an extra pull-up current through CTRL[n], and connected to VDD through switching devices SW1 and MP1. At the same time, the VI[n] signal connected to SV[n] can be given an extra pull-down current through CTRL[n], and connected to GND ground through switching devices SW2 and MP2.

[0067] Combination Figure 4 and Figure 5 As shown, the working principle of the short-circuit test circuit 100 is as follows: the CTRL[n] signal connected to the touch point SV[n] of the CTRL[n] row is set to a low level; at the same time, the CTRL[n-1] signal connected to the touch point SV[n+1] of the CTRL[n-1] row is set to a high level. When no short circuit occurs, the CTRL[n] signal connected to the touch point 300 of the CTRL[n] row is at a low level, the switching devices SW1 and MP1 are turned on, and the switching devices SW2 and MP2 are turned off. Excess charging current flows from VDD through the switching devices MP1 and SW1 to charge one end of the capacitor Cfb, and positive charge accumulates continuously. Since the voltage across the capacitor cannot change abruptly, when the positive charge on one end of the capacitor increases, the negative charge on the other end must also increase. That is, some current is drawn from the output of the charge amplifier 131 to increase the negative charge on the other end of the capacitor Cfb, achieving a balance of positive and negative charges on both ends of the capacitor, and the first voltage signal V CA Therefore, it decreases until it decreases to GND, which is the voltage of 0.

[0068] Similarly, when the CTRL[n-1]th row touch point is connected to a high-level CTRL[n-1] signal, switching devices SW1 and MP1 are off, while switching devices SW2 and MP2 are on. Excess discharge current flows from one end of capacitor Cfb through switching devices SW2 and MP2 to GND, continuously drawing positive charge away from GND. Since the voltage across the capacitor cannot change abruptly, when the positive charge on one side of the capacitor decreases, the negative charge on the other side must also decrease. This means charging the output of charge amplifier 131, causing the negative charge on the other side of capacitor Cfb to decrease accordingly, achieving a balance of positive and negative charges on both sides of the capacitor. The first voltage signal V CA Therefore, it increases until it increases to VDD. Figure 5The dashed lines of the arrows in the diagram show the charging and discharging directions of the excess current in the two cases.

[0069] When a short circuit occurs, assuming SV[n] and SV[n+1] are short-circuited, then V I [n] and V I [n+1] is simultaneously connected to conducting switching devices MP1[n] and SW1[n], and to cut off switching devices MP2[n] and SW2[n]. It also connects to cut-off switching devices MP1[n+1] and SW1[n+1], and to conducting switching devices MP2[n+1] and SW2[n+1]. Both pull-up and pull-down currents are connected to SV[n] and SV[n+1]. Assuming the pull-up and pull-down currents are equal and cancel each other out, therefore V... I [n] and V I [n+1] is sampled normally, and the first voltage signal V CA It is at a normal intermediate level.

[0070] Combination Figure 4 and Figure 5 As shown, when the two touch points SV[n] and SV[n+1] to be tested are not short-circuited, the pull-up current connected to the touch point 300 in the CTRL[n]th row causes excess current to charge from VDD, and the first voltage signal V at the output of the charge amplifier 131... CA Therefore, it becomes smaller; the pull-down current connected to the touch point 300 in the CTRL[n-1]th row causes excess current to discharge to GND, and the first voltage signal V at the output of the charge amplifier 131... CA Therefore, it increases. When the two touch points SV[n] and SV[n+1] are short-circuited, the touch point SV[n+1] in the CTRL[n-1]th row is short-circuited with the touch point SV[n] in the CTRL[n]. Therefore, the first voltage signal V on touch points SV[n] and SV[n+1] increases. CA Since the short circuit simultaneously connects the current charging from VDD and the current discharging to GND, assuming the pull-up current and the sink current are approximately equal, then the first voltage signal V at the touch point 300 corresponding to these two short circuits is... CA The voltage level is consistent with normal sampling operation, approximately equal to Vex, and the first voltage signal V is at the intermediate level. CA It remains unchanged.

[0071] See Figure 6The diagram shows an example of the operating waveform of a short-circuit test circuit connected to a touch point in row CTRL[n]. If no short circuit occurs, because the short-circuit test circuit 100 connected to touch point 300 in row CTRL[n] adds an extra pull-up current to VDD, when CTRL[n] is low, the short-circuit test circuit 100 connected to touch point 300 in that row is connected to a pull-up current by the low-level CTRL[n] signal. The excitation voltage signal Vex at the positive input of charge amplifier 131 operates normally (assuming, for example, a high or low level within the range of 1V to 4V). When charge amplifier 131 is reset by the reset control signal RESET of reset control switch 133 at the end of the excitation voltage signal Vex being low (1V), reset control switch 133 is opened. Due to the virtual short principle, the charge conversion signal V... I First, following the change in the excitation voltage signal Vex to a high level (4V), as time progresses, the pull-up current formed by switching devices MP1 and SW1 charges more positive charge into the left plate of capacitor Cfb. To maintain the charge balance across the plates, more negative charge is drawn away from the output of charge amplifier 131 and accumulates on the right plate of capacitor Cfb. Therefore, compared to the charge conversion signal V at this time... I (4V), First voltage signal V CA The voltage then decreases (from 4V to 3.2V).

[0072] Then, after the charge amplifier 131 is reset by the reset control switch 133 at the end of Vex being high (4V), the reset control switch 133 is opened. Due to the virtual short principle, the charge conversion signal V... I Initially, following the change in the excitation voltage signal Vex to a low level (1V), as time progresses, the pull-up current formed by switching devices MP1 and SW1 charges more positive charge into the left plate of capacitor Cfb. To maintain the charge balance across the plates, more negative charge is drawn away from the output of charge amplifier 131 and accumulates on the right plate of capacitor Cfb. Therefore, compared to the charge conversion signal V at this time... I (1V), First voltage signal V CA It then decreases (from 1V to 0V) until it decreases to GND.

[0073] Similarly, if no short circuit occurs, the short circuit test circuit connected to the touch point in row CTRL[n-1] will, based on the pull-down current, ultimately produce the first voltage signal V. CA It will increase to VDD.

[0074] Based on the same inventive concept, this application provides a touch sampling circuit, see [link to relevant documentation]. Figure 7As shown, the touch sampling circuit 10 includes a signal processing circuit 200 and a short-circuit test circuit 100 according to any embodiment of this application.

[0075] The signal processing circuit 200 is electrically connected to the output terminal of the charge conversion unit 130. The signal processing circuit 200 is used to set and process the first voltage signal and output a digital signal. The digital signal is used to represent the voltage amplitude change of the first voltage signal to determine whether the touch point 300 is short-circuited.

[0076] Optionally, the digital signal includes a first type of digital signal, a second type of digital signal, and a third type of digital signal; when the first voltage signal increases, the signal processing circuit 200 outputs the first type of digital signal; when the first voltage signal decreases, the signal processing circuit 200 outputs the second type of digital signal; when the first voltage signal remains unchanged, the signal processing circuit 200 outputs the third type of digital signal.

[0077] Combination Figure 5 As shown, the first voltage signal V CA When the voltage increases to the preset voltage VDD, the first voltage signal V CA For the maximum value, all values ​​of the first type of digital signal can be 1, representing the first voltage signal V. CA This is the maximum value; the first voltage signal V CA When it decreases to GDN (i.e., 0V), the first voltage signal V CA To be the minimum value, the second type of digital signal can be all 0, representing the first voltage signal V. CA This is the minimum value. Therefore, the third type of digital signal can be any digital signal mixed with 0 and 1. Unlike the first and second types of digital signals, the third type of digital signal represents the first voltage signal V. CA The level is at the middle level and remains unchanged; the touch point 300 is short-circuited.

[0078] The touch sampling circuit 10 of this application belongs to the field of touch technology. It converts the touch information of a finger into recognizable digital information through sampling circuits, conversion circuits, amplification circuits, and other technologies for further display and response processing. It is widely used in various fields with touch functions, such as mobile phones, tablet computers, in-vehicle screens, touch TVs, and touch electronics.

[0079] In some embodiments, the signal processing circuit 200 includes a third switching unit 210 and a sampling unit 220; the first terminal of the third switching unit 210 is electrically connected to the output terminal of the charge conversion unit 130. The second and third terminals of the third switching unit 210 are used to receive the first reference signal and the second reference signal, respectively. The fourth and fifth terminals of the third switching unit 210 are electrically connected to the first and second terminals of the sampling unit 220, respectively. The first reference signal and the second reference signal correspond to the low level and high level of the excitation voltage signal, respectively. The sampling unit 220 is used to output a first set of differential signals from the third and fourth terminals of the sampling unit 220 according to the first voltage signal and the first reference signal when the first voltage signal is low and the first and fifth terminals of the third switching unit 210 are turned on and the second and fourth terminals are turned on; and to output a second set of differential signals from the third and fourth terminals of the sampling unit 220 according to the first voltage signal and the second reference signal when the first voltage signal is high and the first and fourth terminals of the third switching unit 210 are turned on and the third and fifth terminals are turned on. Among them, the low level and the high level are the first voltage signal that decreases to zero and the first voltage signal that increases to a preset voltage, respectively; the digital signal is determined by comparing the first group of differential signals or by comparing the second group of differential signals.

[0080] The sampling circuit of this application embodiment can realize the sampling unit 220 being reused twice by turning on different terminals of the third switching unit 210. It can sample twice within one excitation voltage cycle. In this way, each signal processing circuit 200 only needs to be configured with one sampling unit 220, thereby greatly reducing the power consumption or area required by the signal processing circuit 200.

[0081] Meanwhile, a sampling unit 220 in this embodiment can acquire signals within one excitation voltage cycle and generate two sets of differential signals within one excitation voltage cycle, which facilitates flexible signal processing and can effectively reduce noise impact and improve the signal-to-noise ratio.

[0082] Optionally, the third switching unit 210 is a combination of multiple control switches. By controlling some control switches to be open and some control switches to be open, different terminals of the third switching unit 210 are turned on, so that the corresponding signals are input to the sampling unit 220.

[0083] Optionally, the control unit 140 controls the conduction of different terminals of the third switching unit 210 based on the excitation voltage signal and the sampling signal. The third switching unit 210 receives the excitation voltage signal and the sampling signal, and outputs control signals to each control switch of the third switching unit 210 according to the received excitation voltage signal and the sampling signal. Those skilled in the art can select the signals connected to the input terminals of the control unit 140 according to the actual design, so that the control signals output by the control unit 140 satisfy the above conditions.

[0084] Optionally, see Figure 8As shown, the third switch unit 210 includes a first control switch 211, a second control switch 212, a third control switch 213, and a fourth control switch 214. The first terminal of the first control switch 211 serves as the second terminal of the third switch unit 210. The second terminals of the first control switch 211 and the second terminals of the second control switch 212 together serve as the fourth terminal of the third switch unit 210. The first terminals of the second control switch 212 and the third control switch 213 together serve as the first terminal of the third switch unit 210. The second terminals of the third control switch 213 and the fourth control switch 214 together serve as the fifth terminal of the third switch unit 210. The first terminal of the fourth control switch 214 serves as the third terminal of the third switch unit 210.

[0085] Optionally, the control unit 140 is electrically connected to the control terminals of the first control switch 211, the second control switch 212, the third control switch 213, and the fourth control switch 214, and is used to control the on and off states of the first control switch 211, the second control switch 212, the third control switch 213, and the fourth control switch 214.

[0086] See Figure 8 As shown, the voltage value of REFH is the excitation voltage signal V. EX The voltage value during the high-level phase, the voltage value of REFL is the excitation voltage signal V. EX The voltage value during the low-level phase. Select the excitation voltage signal V. EX The high-level phase signal is used as the second reference signal, and the excitation voltage signal V is selected. EX Using the low-level phase signal as the first reference signal can avoid the influence of other voltages on the sampling unit 220, such as reducing parasitic capacitance, improving the sensitivity and stability of the sampling unit 220, etc.

[0087] Optionally, the second reference signal REFH and the first reference signal REFL can be replaced with VDD and GND respectively to adapt to the excitation voltage signal V. EX The maximum and minimum values ​​of the excitation voltage signal V are used to the maximum extent. EX The input voltage range.

[0088] This application embodiment can utilize a first voltage signal V at a high potential. CA When comparing with the high-potential second reference signal REFH, the second reference signal REFH is replaced with VDD, while when comparing with the low-potential first voltage signal VDD... CA When comparing with the low-level first reference signal REFL, REFL is replaced with GND to further accommodate a wider input voltage range of the sample-and-hold amplifier.

[0089] Optionally, see Figure 8As shown, the sampling unit 220 includes a first sampling capacitor 221, a second sampling capacitor 222, a sampling amplifier 223, a first holding capacitor 224, and a second holding capacitor 225. The sampling amplifier 223 can be a sample-and-hold amplifier. When converting analog signals to digital signals, a certain conversion time is required. During this conversion time, the analog signal must remain basically unchanged to ensure conversion accuracy.

[0090] Optionally, in the first sampling phase, the first voltage signal V CA When the voltage level is low, the second sampling capacitor 222 and the second holding capacitor 225 operate according to the first voltage signal V. CA The changes are stored and sampled. The charges at the second terminals of the second sampling capacitor 222 and the first sampling capacitor 221 are different, so that the first and second output terminals of the sampling amplifier 223 can output a set of differential signals. In the second sampling stage, the first voltage signal V CA When the voltage level is low, the first sampling capacitor 221 and the first holding capacitor 224 are adjusted according to the first voltage signal V. CA The changes are stored and sampled. The charges at the second terminals of the first sampling capacitor 221 and the second sampling capacitor 222 are different, so that the first output terminal and the second output terminal of the sampling amplifier 223 can output a set of differential signals.

[0091] Optionally, see Figure 8 As shown, Csp represents the first sampling capacitor 221, Csn represents the second sampling capacitor 222, SHA represents the sampling amplifier 223, and V IN V represents the signal output from the inverting input terminal (i.e., the first output) of the sampling amplifier 223. IP This represents the signal output from the positive input terminal (second output) of sampling amplifier 223, where Chp represents the first holding capacitor 224, Chn represents the second holding capacitor 225, and V... OP V represents the signal output from the third terminal of the sampling amplifier 223. ON V represents the signal output from the fourth terminal of the sampling amplifier 223. OP and V ON A set of differential signals is formed.

[0092] Optionally, see Figure 8 As shown, in the first sampling phase, the first voltage signal V CA When the voltage level is low, both the first control switch 211 and the third control switch 213 are turned on, while both the second control switch 212 and the fourth control switch 214 are turned off, and the first voltage signal V... CA The sampling capacitor Csn is connected to the positive input terminal of the sampling amplifier 223, which will convert V... IPThe first reference signal REFL or GND is connected to the inverting input of the sampling amplifier 223 via the sampling capacitor Csp, and V... IN The signal is input to the sampling amplifier 223, making the first voltage signal V, which has a low DC potential, work. CA The first reference signal REFL or GND is applied to the two input terminals of the sampling unit 120, and through the corresponding sampling capacitor and holding capacitor, a set of differential signals V is output. OP and V ON .

[0093] Optionally, during the second sampling phase, both the second control switch 212 and the fourth control switch 214 are turned on, while both the first control switch 211 and the third control switch 213 are turned off, and the first voltage signal V... CA When it is high, the first voltage signal V CA The sampling capacitor Csp is connected to the inverting input of the sampling amplifier 223, which converts V... IN The signal is input to sampling amplifier 223. The second reference signal REFH or VDD is connected to the positive input terminal of sampling amplifier 223 via sampling capacitor Csn, thus converting VDD into a signal. IP The signal is input to the sampling amplifier 223, making the first voltage signal V, which has a high DC potential, high. CA The second reference signal REFH or VDD is applied to the two input terminals of the sampling unit 120, and through the corresponding sampling capacitor and holding capacitor, a set of differential signals V is output. OP and V ON .

[0094] Since the signal processing circuit 200 of this embodiment uses only one sampling unit 220, the capacitance area of ​​the first sampling capacitor 221, the second sampling capacitor 222, the first holding capacitor 224 and the second holding capacitor 225 can be halved. At the same time, since only one sampling amplifier 223 is used, the power consumption of the entire sampling unit 120 can also be reduced by half.

[0095] In this application embodiment, the sampling amplifier 223 of the sampling unit 220 is reused twice by different combinations of opening and closing control switches within one excitation voltage signal cycle. This includes, but is not limited to, changes in switch combination logic control, all of which are within the scope of protection of this patent.

[0096] In some embodiments, see Figure 8As shown, the signal processing circuit 200 further includes: a signal conversion unit 230; the first input terminal and the second input terminal of the signal conversion unit 230 are respectively used to electrically connect to the third terminal and the fourth terminal of the sampling unit 220; the signal conversion unit 230 is used to compare the first group of differential signals or compare the second group of differential signals to obtain the comparison result, and convert the comparison result into a digital signal output.

[0097] Optionally, the signal conversion unit 230 includes a comparator and a converter. The first input terminal and the second input terminal of the comparator serve as the first input terminal and the second input terminal of the signal conversion unit 230, respectively. The output terminal of the comparator is electrically connected to the input terminal of the converter. The comparator is used to compare a first set of differential signals or a second set of differential signals to obtain a comparison result, and outputs the comparison result to the converter. The converter is used to convert the comparison result into a digital signal.

[0098] When digital filtering is used in the embodiments of this application, the area of ​​a single analog-to-digital converter can be made smaller, and the source data generated by the analog-to-digital converter can be easily processed by algorithms through digital filtering. The resulting data is more flexible in application, and the error of data deviation will be significantly reduced. Digital filtering can be well applied in signal processing circuits that do not require high speed of analog-to-digital converters but require small area and more flexible data.

[0099] Optionally, see Figure 8 As shown, in this embodiment of the application, the signal conversion unit 230, on the analog side, receives the input signal after passing through the charge conversion unit 130, and directly connects to the analog-to-digital converter (ADC) for analog-to-digital conversion without going through the INT function. The ADC essentially performs the comparator and converter functions of the signal conversion unit 230; alternatively, the comparator is not shown in the figure, and the ADC functions as a converter. The signal conversion unit 230 in this embodiment is based on digital signal processing and integration, making it relatively easy to perform digital filtering on the source data. It is suitable for implementation using a medium-frequency ADC. The disadvantage is that the number of interactive signals between analog and digital signals is too large. The ADC can feed back the common-mode voltage VCM to the sampling amplifier 223.

[0100] Alternatively, assuming the pull-up current and the sink current are approximately equal, then the first voltage signal V at the two short-circuited touch points 300 is equivalent to... CAThe voltage level is the same as during normal sampling, approximately equal to Vex. The code obtained after normal sampling by the analog-to-digital converter (ADC) is an intermediate code, which is inconsistent with the maximum or minimum code obtained when there is no short circuit. When there is no short circuit, the voltage of the touch point affected by the pull-up or pull-down current is either high or low, so the obtained code is either the maximum or minimum value, thus distinguishing whether there is a short circuit.

[0101] Based on the touch sampling circuit 10 of this application embodiment, if no short circuit occurs, the first voltage signal V connected to the touch point 300 in the CTRL[n]th row touch point 300 is... CA The output is GND, which, after passing through the sample-and-hold circuit SHA and the analog-to-digital converter ADC, will yield the minimum 10-bit digital code. The sampling circuit VCA connected to the touch point in row CTRL[n-1] outputs VDD, which, after passing through the sample-and-hold circuit SHA and the analog-to-digital converter ADC, will yield the maximum 10-bit digital code.

[0102] If a short circuit occurs, the first voltage signal V connected to the short-circuited touch point 300 will be... CA The output is a normal signal (typically a level between 1 and 4V). After passing through the sample-and-hold circuit (SHA) and the analog-to-digital converter (ADC), it yields a 10-bit digital code of intermediate value. This allows for easy batch detection of short circuits between touch points.

[0103] Combination Figure 4 and Figure 8 As shown, when rows CTRL[n-2], CTRL[n-1], CTRL[n], CTRL[n+1], and CTRL[n+2] are 10101 respectively, meaning the signals CTRL[n-2], CTRL[n-1], CTRL[n], CTRL[n+1], and CTRL[n+2] are high, low, high, low, and high respectively, if SV[n+1] and SV[n] are short-circuited, then since the signals CTRL[n-1] and CTRL[n] are low and high respectively, pull-up and pull-down currents are added to the short-circuit test circuit 100 connected to the two touch points 300 respectively. Therefore, the pull-up and pull-down currents cancel each other out, and the analog-to-digital converter (ADC) will output an intermediate code, which will be distinguished from the maximum or minimum code output by other non-short-circuited touch points and identified.

[0104] If SV[n+1] and SV[x] are short-circuited, then since the CTRL[n-1] and CTRL[n+1] signals in their respective rows CTRL[n-1] and CTRL[n+1] are all at low level, the two short-circuited touch points 300 will still only have pull-up current. Therefore, the analog-to-digital converter (ADC) will still output the maximum code, which cannot be distinguished from the maximum or minimum code output by other non-short-circuited touch points, so the short-circuit situation cannot be identified.

[0105] As an example, in this embodiment, after adding 10101 and scanning the high and low levels of the odd and even rows, a combination of 11001100 is added. When the CTRL[n-2], CTRL[n-1], CTRL[n], CTRL[n+1], and CTRL[n+2] rows are 11001 respectively, i.e., the CTRL[n-2], CTRL[n-1], CTRL[n], CTRL[n+1], and CTRL[n+2] signals are high, high, low, low, and high respectively, if SV[n+1] and SV[x] are short-circuited, then since the CTRL[n-1] and CTRL[n] signals are high and low respectively, pull-down current and pull-up current are added to the short-circuit test circuit 100 connected to the two touch points 300 respectively. Therefore, the pull-up and pull-down currents cancel each other out, and the analog-to-digital converter (ADC) will output an intermediate code, which is distinguished from the maximum or minimum code output by other non-short-circuited touch points and is identified.

[0106] Similarly, if SV[z] and SV[y] are short-circuited, then since the CTRL[n-2] and CTRL[n+2] signals in the CTRL[n-2] and CTRL[n+2] rows are both high in the two combined scan test cases described above, the two short-circuited touch points 300 will only have pull-down current. Therefore, the analog-to-digital converter ADC will still output the minimum code, which cannot be distinguished from the maximum or minimum code output by other non-short-circuited touch points, so the short-circuit situation cannot be identified.

[0107] As an example, in this embodiment of the application, after scanning and detecting the combination of 10101, the high and low levels of the odd and even rows, and 11001100, the combination of 111000111000 is added. When the CTRL[n-2], CTRL[n-1], CTRL[n], CTRL[n+1], and CTRL[n+2] rows are 11100 respectively, i.e., the CTRL[n-2], CTRL[n-1], CTRL[n], CTRL[n+1], and CTRL[n+2] signals are high, high, high, low, and low respectively, if SV[z] and SV[y] are short-circuited, then since the CTRL[n-2] and CTRL[n+2] signals are high and low respectively, pull-down current and pull-up current are added to the short-circuit test circuit 100 connected to the two touch points 300 respectively. Therefore, the pull-down and pull-up currents cancel each other out, and the analog-to-digital converter (ADC) will output an intermediate code, which can be distinguished from the maximum or minimum code output by other non-short-circuited touch points and identified.

[0108] By adding various combinations for short-circuit test scanning, it can be ensured that no short-circuit situation will be missed.

[0109] This application embodiment involves adding redundant pull-up and pull-down currents to the entire normally operating short-circuit test circuit 100. Short-circuit scanning of the row touch points is performed using multiple combinations, including but not limited to 101010 (odd / even) combinations, 11001100 combinations, 111000111000 combinations, etc., until the entire touch panel points are included.

[0110] In this embodiment, the pull-up current connected to the touch point in the CTRL[n]th row allows excess current to charge VDD, and the first voltage signal V at the output of the charge amplifier 131... CA Therefore, it becomes smaller; the pull-down current connected to the touch point in the CTRL[n+i] (i=…,-2,-1,1,2,…) row causes excess current to discharge to GND, and the first voltage signal V at the output of the charge amplifier 131... CA Therefore, it increases. When a short circuit occurs, the touch points in the CTRL[n]th row and the CTRL[n+i]th row are short-circuited, and the pull-up and pull-down currents cancel each other out. Then, the first voltage signal V at the output terminal of the charge amplifier 131 connected to these two short-circuited touch points 300 is equivalent to... CA The voltage level is consistent with normal sampling operation, at the intermediate level. The code obtained after normal sampling by the analog-to-digital converter (ADC) is inconsistent with the code obtained when there is no short circuit. Since the touch point without a short circuit only has pull-up or pull-down current, the first voltage signal V at the output of the charge amplifier 131 is... CAThe maximum or minimum value is used to determine the code obtained after passing through the analog-to-digital converter (ADC). This allows for the differentiation of short circuits, effectively shortening the short-circuit testing time for the entire chip during mass production and ensuring that no short-circuit touch point is missed.

[0111] Based on the same inventive concept, embodiments of this application provide a display device, including a touch panel, and a short-circuit test circuit 100 as in any embodiment of this application or a touch sampling circuit 10 as in any embodiment of this application.

[0112] See Figure 8 As shown, the touch panel includes multiple touch points 300, each touch point 300 being electrically connected to the first input terminal of a charge conversion unit 130.

[0113] The display device provided in this application has the same inventive concept and the same beneficial effects as the short-circuit test circuits of the previous embodiments. For the contents not shown in detail in this display device, please refer to the short-circuit test circuits of the previous embodiments, which will not be repeated here.

[0114] Those skilled in the art will understand that the steps, measures, and solutions in the various operations, methods, and processes discussed in this application can be alternated, modified, combined, or deleted. Furthermore, other steps, measures, and solutions in the various operations, methods, and processes discussed in this application can also be alternated, modified, rearranged, decomposed, combined, or deleted. Furthermore, steps, measures, and solutions in the prior art that are similar to those disclosed in this application can also be alternated, modified, rearranged, decomposed, combined, or deleted.

[0115] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0116] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0117] It should be understood that although the steps in the flowcharts of the accompanying figures are shown sequentially as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the accompanying figures may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the sub-steps or stages of other steps.

[0118] The above description is only a partial embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A short-circuit test circuit for electrical connection to a touch point, characterized in that, include: The unit comprises a first switching unit, a second switching unit, and a charge conversion unit. The first terminal and the control terminal of the first switching unit are respectively used to receive a preset voltage and a control signal; the first terminal and the control terminal of the second switching unit are respectively used to ground and receive a control signal; the control signal includes a first level and a second level. The first input terminal of the charge conversion unit is electrically connected to the second terminal of the first switching unit and the second terminal of the second switching unit. The first input terminal and the second input terminal of the charge conversion unit are used to receive the charge conversion signal and the excitation voltage signal, respectively, and the output terminal of the charge conversion unit is used to output the first voltage signal; the charge conversion signal is obtained based on the parasitic capacitance of the touch point, and the first voltage signal is obtained by converting the charge conversion signal based on the excitation voltage signal; The short-circuit test circuit is used to test two touch points. If the first switch unit and the second switch unit corresponding to one touch point receive the first level, the first switch unit is turned on, and the second switch unit is turned off, the first voltage signal at the output terminal of the charge conversion unit corresponding to that touch point decreases. If the first switch unit and the second switch unit corresponding to the other touch point receive the second level, the first switch unit is turned off, and the second switch unit is turned on, the first voltage signal at the output terminal of the charge conversion unit corresponding to that other touch point increases, then the two touch points are not short-circuited. The two touch points are one touch point in each of any two rows of touch points, and the control signal received by the short-circuit test circuit corresponding to each row of touch points is the same. The short-circuit test circuit is also used to test two touch points. If the first switch unit and the second switch unit corresponding to one touch point receive the first level, the first switch unit is turned on and the second switch unit is turned off, and the first switch unit and the second switch unit corresponding to the other touch point receive the second level, the first switch unit is turned off and the second switch unit is turned on, and the first voltage signal at the output terminal of the charge conversion unit corresponding to the two touch points remains unchanged, then the two touch points are short-circuited.

2. The short-circuit test circuit according to claim 1, characterized in that, Also includes: The control unit is electrically connected to the control terminal of the first switch unit and the control terminal of the second switch unit, and is used to output the control signal to the first switch unit and the second switch unit corresponding to each touch point, so that the short circuit test circuit corresponding to the two touch points respectively receives the first level and the second level; The control signals corresponding to each row of touch points form a set of level sequences. The control unit outputs multiple sets of level sequences to each row of touch points. Each set of level sequences is formed by combining a first level and a second level in a preset order.

3. The short-circuit test circuit according to claim 1, characterized in that, The first switching unit includes a first switching module and a second switching module; The first end of the first switch module and the second end of the second switch module serve as the first end and the second end of the first switch unit, respectively, and the control end of the second switch module serves as the control end of the first switch unit. The control terminal and the second terminal of the first switch module are electrically connected to the first terminal of the second switch module.

4. The short-circuit test circuit according to claim 1, characterized in that, The second switching unit includes a third switching module and a fourth switching module; The first end of the third switch module and the second end of the fourth switch module serve as the first end and the second end of the second switch unit, respectively, and the control end of the fourth switch module serves as the control end of the second switch unit. The control terminal and the second terminal of the third switch module are electrically connected to the first terminal of the fourth switch module.

5. The short-circuit test circuit according to claim 1, characterized in that, The charge conversion unit includes: a charge amplifier, a reset capacitor, and a reset control switch; The first input terminal, the second input terminal, and the output terminal of the charge amplifier serve as the first input terminal, the second input terminal, and the output terminal of the charge conversion unit, respectively. The first and second terminals of the reset capacitor are electrically connected to the first input terminal and the output terminal of the charge amplifier, respectively. The first and second terminals of the reset control switch are electrically connected to the first input terminal and the output terminal of the charge amplifier, respectively. The control terminal of the reset control switch is used to receive a reset control signal to control the switching on and off.

6. The short-circuit test circuit according to claim 5, characterized in that, The charge conversion unit further includes: a first capacitor; The first terminal of the first capacitor is electrically connected to the first input terminal of the charge amplifier; The second terminal of the first capacitor is used to receive the excitation voltage signal.

7. A touch sampling circuit, characterized in that, include: The signal processing circuit and the short-circuit test circuit as described in any one of claims 1-6; The signal processing circuit is electrically connected to the output terminal of the charge conversion unit and is used to set and process the first voltage signal to output a digital signal; the digital signal is used to represent the voltage amplitude change of the first voltage signal to determine whether the touch point is short-circuited.

8. The touch sampling circuit according to claim 7, characterized in that, The signal processing circuit includes a third switching unit and a sampling unit; The first terminal of the third switching unit is electrically connected to the output terminal of the charge conversion unit; The second and third terminals of the third switching unit are used to receive the first reference signal and the second reference signal, respectively. The fourth and fifth terminals of the third switching unit are electrically connected to the first and second terminals of the sampling unit, respectively. The first reference signal and the second reference signal correspond to the low level and high level of the excitation voltage signal, respectively. The sampling unit is configured to output a first set of differential signals from the third and fourth terminals of the sampling unit based on the first voltage signal and the first reference signal when the first voltage signal is low and the first and fifth terminals of the third switching unit are connected and the second and fourth terminals are connected; and to output a second set of differential signals from the third and fourth terminals of the sampling unit based on the first voltage signal and the second reference signal when the first voltage signal is high and the first and fourth terminals of the third switching unit are connected and the third and fifth terminals are connected. Wherein, the low level and the high level are respectively a first voltage signal that decreases to zero and a first voltage signal that increases to a preset voltage; the digital signal is determined based on a comparison of the first set of differential signals or a comparison of the second set of differential signals.

9. The touch sampling circuit according to claim 8, characterized in that, The signal processing circuit further includes: a signal conversion unit; The first and second input terminals of the signal conversion unit are respectively used to electrically connect to the third and fourth terminals of the sampling unit; The signal conversion unit is used to compare the first group of differential signals or the second group of differential signals to obtain a comparison result, and convert the comparison result into the digital signal output.

10. A display device, characterized in that, Includes a touch panel, and a short-circuit test circuit as described in any one of claims 1-6 or a touch sampling circuit as described in any one of claims 7-9; The touch panel includes multiple touch points, each of which is electrically connected to a first input terminal of a charge conversion unit.

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