Fingerprint acquisition circuit, chip and electronic equipment

Abstract

This disclosure relates to a fingerprint acquisition circuit, chip, and electronic device. The circuit includes multiple switching modules, a signal processing module, and a computing module. Each switching module corresponds to a pixel module, and each pixel module includes multiple pixel units. The switching modules are used to output the touch signal of any one pixel unit in the corresponding pixel module or the touch signal of multiple pixel units connected in parallel. The signal processing module is used to process the received touch signal to obtain a digital touch signal. The computing module is used to perform calculations on the digital touch signal to obtain a fingerprint image. Embodiments of this disclosure support fingerprint signal acquisition at various DPIs. Based on different DPI scenarios, the number of pixel units included in the pixel module is determined as needed, and multiple pixel units are activated to increase the amount of fingerprint signal, improve fingerprint acquisition speed, and thus improve fingerprint recognition efficiency.

Description

Technical Field

[0001] This disclosure relates to the field of fingerprint recognition technology, and in particular to a fingerprint acquisition circuit, chip, and electronic device. Background Technology

[0002] More and more electronic devices are now equipped with fingerprint recognition for identity verification. During fingerprint acquisition, the technology typically detects each pixel in the fingerprint sensor sequentially. However, this method is slow, has low efficiency, and cannot handle fingerprint data acquisition at various DPI (Dots Per Inch) levels. Summary of the Invention

[0003] According to one aspect of this disclosure, a fingerprint acquisition circuit is provided for acquiring a fingerprint from a fingerprint sensing component comprising multiple pixel units, wherein the pixel units are used to generate corresponding touch signals in response to touch of a target object, and the circuit includes multiple switching modules, a signal processing module, and a computing module, wherein:

[0004] Each switch module corresponds to a pixel module, and each pixel module includes multiple pixel units. The switch module is used to output the touch signal of any one pixel unit in the corresponding pixel module or the touch signal of multiple pixel units connected in parallel.

[0005] The signal processing module is used to process the received touch signal to obtain a digital touch signal;

[0006] The computing module is used to perform calculations on the digital touch signal to obtain a fingerprint image.

[0007] In one possible implementation, each pixel unit includes a sensing capacitor, and the touch signal obtained by connecting the plurality of pixel units in parallel is the signal output by connecting the sensing capacitors of the plurality of pixel units in parallel.

[0008] In one possible implementation, the switch module includes a first switch unit, the first switch unit including a plurality of first control switches, and the first control switches including a plurality of connection terminals, wherein...

[0009] Each first control switch has its first terminal connected to the output terminal of its corresponding pixel unit, its second terminal connected to the signal processing module, and its third terminal connected to the output terminal of the target pixel unit. Each first control switch's control terminal is used to receive a first control signal. The output terminal of the target pixel unit is connected to the signal processing module.

[0010] The target pixel unit is one of the pixel units in the pixel module.

[0011] In one possible implementation, the first control signal is used to enable the first terminal of each first control switch to connect with the second terminal to form a first channel, or to enable the first terminal of each first control switch to connect with the third terminal to form a second channel.

[0012] When the first channel is active, the touch signal of each pixel unit is output to the signal processing module.

[0013] When the second channel is active, the touch signal of each pixel unit connected in parallel is output to the signal processing module.

[0014] In one possible implementation, the switch module further includes a second switch unit, which includes a plurality of second control switches, each with a plurality of connection terminals, and the second control switches are distributed in a multi-level manner.

[0015] The first terminal of each second control switch in the first stage is connected to the second terminal of the corresponding first control switch, the second terminal of each second control switch is connected to the third terminal of the second control switch in the next stage, and the third terminal of each second control switch is connected to the second terminal of another corresponding first control switch or the output terminal of the target pixel unit. The first control switches connected to the first terminals of each second control switch are different.

[0016] One or more second-level control switches have their first terminals connected to the second terminals of their corresponding second-level control switches in the previous level, and their third terminals are connected to the second terminals of another corresponding second-level control switch in the previous level.

[0017] Among them, the second control switches connected to the first and third ends of each second control switch are different;

[0018] The second terminal of the last second-level second control switch is connected to the signal processing module.

[0019] In one possible implementation, each level of the second control switch is used to receive the second control signal of each level, so as to output the touch signal of any pixel unit or the touch signal of multiple pixel units connected in parallel to the signal processing module, wherein the number of the signal processing modules is 1.

[0020] In one possible implementation, when the pixel module is an n×n pixel array, the second switching unit includes n stages, and the second switching unit includes 2 stages. n -1 second control switches, the i-th level includes i second control switches, where i and n are both positive integers greater than 1 and i≤n, and the n-th level is the first level.

[0021] In one possible implementation, the number of signal processing modules includes multiple modules, each connected to the output terminal of a respective switching module. Each switching module further includes a third switching unit disposed between the signal processing module and the arithmetic module. The third switching unit includes multiple third control switches, each third control switch including multiple connection terminals.

[0022] The first terminal of each third control switch is connected to the output terminal of the corresponding signal processing module, the second terminal of each third control switch is connected to the arithmetic module, and the control terminal of each third control switch is used to receive the first control signal.

[0023] The first control signal is also used to control the conduction state of each third control switch.

[0024] In one possible implementation, the switch module further includes a fourth switch unit, which includes a plurality of fourth control switches, each of which includes a plurality of connection terminals, wherein...

[0025] The first terminal of each fourth control switch is connected to the output terminal of the corresponding pixel unit, and the second terminal of each fourth control switch is connected to the signal processing module. The first control terminal of each fourth control switch is used to receive row control signals, and the second control terminal of each fourth control switch is used to receive column control signals.

[0026] The row control signal and the column control signal are used to determine the switching state of each fourth control switch.

[0027] In one possible implementation, when both the row control signal and the column control signal are valid, each of the fourth control switches is turned on, and the touch signal is generated after multiple pixel units are connected in parallel.

[0028] In one possible implementation, the signal processing module includes:

[0029] The analog signal processing unit is used to process the received touch signals and output the processed touch signals.

[0030] An analog-to-digital conversion unit, connected to the analog signal processing unit, is used to perform analog-to-digital conversion on the processed touch signal to obtain a digital touch signal.

[0031] The number of the analog signal processing unit and the analog-to-digital conversion unit is one or more.

[0032] In one possible implementation, the analog signal processing unit includes a processing switch, an adjustable capacitor, and an operational amplifier, wherein,

[0033] The positive input terminal of the operational amplifier is connected to the first terminal of the processing switch and the first terminal of the adjustable capacitor to receive the touch signal, and the negative input terminal is used to input a reference signal.

[0034] The second terminal of the processing switch is connected to the second terminal of the adjustable capacitor and the output terminal of the operational amplifier.

[0035] In one possible implementation, the analog-to-digital conversion unit includes a first switching switch, a second switching switch, a first conversion capacitor, a second conversion capacitor, and an analog-to-digital converter, wherein,

[0036] The first terminal of the first switch and the second switch are connected to the output terminal of the analog signal processing unit to receive the processed touch signal.

[0037] The second terminal of the first switching switch is connected to the first terminal of the first switching capacitor and the positive input terminal of the analog-to-digital converter, and the second terminal of the second switching switch is connected to the first terminal of the second switching capacitor and the negative input terminal of the analog-to-digital converter.

[0038] The output of the analog-to-digital converter is used to output the digital touch signal.

[0039] According to one aspect of this disclosure, a chip is provided, the chip including the fingerprint acquisition circuit described above.

[0040] According to one aspect of this disclosure, an electronic device is provided, the electronic device including the chip described above.

[0041] In one possible implementation, the electronic device includes a display, a smartphone, or a portable device.

[0042] This embodiment of the present disclosure can realize the output of touch signal of any pixel unit in the corresponding pixel module or the touch signal of multiple pixel units connected in parallel by the switching module through the switching control of the switching module, so as to support fingerprint signal acquisition of multiple DPI. Based on different DPI scenarios, the number of pixel units included in the pixel module can be determined as needed, and multiple pixel units can be turned on to increase the amount of fingerprint signal, increase the fingerprint acquisition speed, and thus improve the fingerprint recognition efficiency.

[0043] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Other features and aspects of this disclosure will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0044] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the specification, serve to illustrate the technical solutions of this disclosure.

[0045] Figure 1 A schematic diagram of a fingerprint acquisition circuit according to an embodiment of the present disclosure is shown.

[0046] Figure 2 A schematic diagram of a fingerprint acquisition circuit according to an embodiment of the present disclosure is shown.

[0047] Figure 3 A schematic diagram of a fingerprint acquisition circuit according to an embodiment of the present disclosure is shown.

[0048] Figure 4 A schematic diagram of a fingerprint acquisition circuit according to an embodiment of the present disclosure is shown.

[0049] Figure 5 A schematic diagram of a fingerprint acquisition circuit according to an embodiment of the present disclosure is shown.

[0050] Figure 6 A control timing diagram of a fourth switching unit according to an embodiment of the present disclosure is shown.

[0051] Figure 7 A schematic diagram of a signal processing module according to an embodiment of the present disclosure is shown.

[0052] Figure 8 A block diagram of an electronic device according to an embodiment of the present disclosure is shown. Detailed Implementation

[0053] Various exemplary embodiments, features, and aspects of this disclosure will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0054] In the description of this disclosure, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure.

[0055] Furthermore, 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. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this disclosure, "a plurality of" means two or more, unless otherwise expressly specified.

[0056] In this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0057] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0058] In this document, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Furthermore, the term "at least one" in this document means any combination of at least two of any one or more elements. For example, including at least one of A, B, and C can mean including any one or more elements selected from the set consisting of A, B, and C.

[0059] Furthermore, to better illustrate this disclosure, numerous specific details are set forth in the following detailed description. Those skilled in the art will understand that this disclosure can be practiced without certain specific details. In some instances, methods, means, components, and circuits well known to those skilled in the art have not been described in detail in order to highlight the main points of this disclosure.

[0060] Please see Figure 1 , Figure 1 A schematic diagram of a fingerprint acquisition circuit according to an embodiment of the present disclosure is shown.

[0061] like Figure 1 As shown, the fingerprint acquisition circuit 1 is used to acquire fingerprints from the fingerprint sensing component 2, which includes multiple pixel units. Each pixel unit generates a corresponding touch signal in response to a touch from a target object. The circuit includes multiple switching modules 10, a signal processing module 20, and a calculation module 30, wherein:

[0062] Each switch module 10 corresponds to a pixel module, and each pixel module includes multiple pixel units. The switch module 10 is used to output the touch signal of any one pixel unit in the corresponding pixel module or the touch signal of multiple pixel units connected in parallel.

[0063] The signal processing module 20 is used to process the received touch signal to obtain a digital touch signal;

[0064] The computing module 30 is used to perform calculations on the digital touch signal to obtain a fingerprint image.

[0065] This embodiment of the disclosure can realize the output of touch signal of any pixel unit in the corresponding pixel module or the touch signal of multiple pixel units connected in parallel through the switching control of the switching module, so as to support fingerprint signal acquisition of multiple DPI. Based on different DPI scenarios, the number of pixel units included in the pixel module can be determined as needed, and multiple pixel units can be turned on to increase the amount of fingerprint signal, increase the fingerprint acquisition speed, and reduce the complexity of fingerprint processing, thereby improving fingerprint recognition efficiency.

[0066] In one example, the fingerprint sensing component 2 can be an N×M array, where N and M are both positive integers, such as... Figure 1 As shown, N and M are both 8, and the fingerprint sensing component 2 includes 8×8 pixel units.

[0067] In one example, a pixel module can be a j×k array, where j and k are both positive integers and are less than or equal to M and N, respectively. For example, j and k are both 2. For instance, pixel module 1 can include pixel units p00, p01, p10, and p11. Each pixel module can be determined by a window in 2×2 units. For example, by moving the selection window to the right from pixel module 1, pixel module 2 can be determined to include pixel units p01, p02, p11, and p12.

[0068] In one example, the number of pixel modules in the fingerprint sensing component 2 is L = (M × N) / (j × k).

[0069] Of course, the above description of the pixel module is exemplary, and the embodiments of this disclosure are not limited thereto. In other embodiments, j and k can be different (such as 2×1, 2×3, etc.) or other numbers. The pixel module can also adopt other division methods, such as using any multiple pixel units in the fingerprint sensing component 2. The embodiments of this disclosure do not limit this.

[0070] In one example, when dividing the pixel modules, the specifications of the pixel modules in the fingerprint sensing component 2 can be the same or different. For example, pixel module 1 can be a 2×2 array and pixel module 2 can be a 3×3 array. This disclosure does not limit the specificity of the embodiments.

[0071] Preferably, the specifications of each pixel module in the embodiments of this disclosure can be the same to facilitate control and achieve fingerprint acquisition more efficiently. For example, each pixel module in the embodiments of this disclosure can be a 2×2 array.

[0072] In one possible implementation, each pixel unit may include a sensing capacitor 21. When a part of the finger touches the pixel unit, the electrical parameters of the sensing capacitor, such as voltage, will change. In one example, the touch signal after the multiple pixel units are connected in parallel is the signal output by the multiple pixel units' sensing capacitors 21 connected in parallel.

[0073] The following provides an example of the possible implementation methods for each module of the circuit.

[0074] In one possible implementation, the switch module 10 may include a first switch unit 110, the first switch unit 110 including a plurality of first control switches 111, the first control switches 111 including a plurality of connection terminals, wherein...

[0075] The first terminal (1) of each first control switch 111 is connected to the output terminal of the corresponding pixel unit, the second terminal (2) of each first control switch 111 is connected to the signal processing module 20, the third terminal (3) of each first control switch 111 is connected to the output terminal of the target pixel unit, the control terminal of each first control switch 111 is used to receive the first control signal SEL, and the output terminal of the target pixel unit is connected to the signal processing module 20.

[0076] The target pixel unit is one of the pixel units in the pixel module.

[0077] In one possible implementation, the first control signal SEL is used to enable the first terminal of each first control switch 111 to connect with the second terminal to form a first channel, or to enable the first terminal of each first control switch 111 to connect with the third terminal to form a second channel.

[0078] When the first channel is active, the touch signal of each pixel unit is output to the signal processing module 20.

[0079] When the second channel is active, the touch signal of each pixel unit connected in parallel is output to the signal processing module 20.

[0080] Please see Figure 2 , Figure 2 A schematic diagram of a fingerprint acquisition circuit according to an embodiment of the present disclosure is shown.

[0081] In one example, such as Figure 2 As shown, this embodiment of the present disclosure takes a pixel module comprising 2×2 pixel units (j=2, k=2) as an example for illustrative purposes. Each pixel unit includes a sensing capacitor 21 and a current source 22.

[0082] In one example, such as Figure 2 As shown, the first end (1) of each first control switch 111 is connected to the output end of the corresponding pixel unit. For example, the first end (1) of the first first control switch 111 is connected to the output end of the sensing capacitor corresponding to the pixel unit p01 (and the positive terminal of the corresponding current source 22). The second end (2) of each first control switch 111 is connected to the signal processing module 20. For example, the second end (2) of the first first control switch 111 is connected to the signal processing module 20. The third end (3) of each first control switch 111 is connected to the output end of the target pixel unit. For example, the third end (3) of each first control switch 111 is connected to the output end of the pixel unit p00. The control end of each first control switch 111 is used to receive the first control signal SEL. The output end of the target pixel unit is connected to the signal processing module 20.

[0083] In one example, such as Figure 2 As shown, when the first control signal SEL is at the first level (e.g., SEL = 0), the first and second terminals of each first control switch 111 are connected to form a first channel, and the touch signal of each pixel unit is output to the signal processing module 20. For example, the touch signal of pixel unit p00 is converted into a digital signal Vout00 by the processing module 20, the touch signal of pixel unit p01 is converted into a digital signal Vout01 by the processing module 20, the touch signal of pixel unit p10 is converted into a digital signal Vout00 by the processing module 20, and the touch signal of pixel unit p11 is converted into a digital signal Vout11 by the processing module 20.

[0084] In one example, such as Figure 2 As shown, when the first control signal SEL is in the second level state (e.g., SEL=1), the first and third terminals of each first control switch 111 are connected to form a second channel, and the sensing capacitors 21 corresponding to each pixel unit are connected in parallel. The parallel touch signal (voltage signal) is output to the signal processing module 20. For example, pixel units p00, p01, p10 and p11 are connected in parallel with each other. Thus, the parallel touch signal is converted into a digital signal Vout00 by the processing module 20.

[0085] It should be noted that the number of signal processing modules 20 in the embodiments of this disclosure may include multiple modules, such as... Figure 2 As shown, when the first control signal SEL is at the first level, each signal processing module is used to process the touch signal of the corresponding pixel unit; when the first control signal SEL is at the second level, any signal processing module (such as the signal processing module corresponding to Vout00) is used to process the touch signal output after the parallel connection of each pixel unit.

[0086] In one possible implementation, each signal processing module 20 is connected to the output terminal of each switch module 10. The switch module 10 further includes a third switch unit 130, which is disposed between the signal processing module 20 and the arithmetic module 30. The third switch unit 130 includes multiple third control switches 131, each third control switch 131 including multiple connection terminals.

[0087] The first terminal of each third control switch 131 is connected to the output terminal of the corresponding signal processing module 20, the second terminal of each third control switch 131 is connected to the arithmetic module 30, and the control terminal of each third control switch 131 is used to receive the first control signal SEL.

[0088] The first control signal SEL is also used to control the conduction state of each of the third control switches 131.

[0089] This embodiment of the disclosure enables path selection between each signal processing module 20 and the arithmetic module 30 by setting a third switch unit 130, thereby efficiently realizing the processing of digital touch signals from multiple signal processing modules 20 using a single arithmetic module.

[0090] Please see Figure 3 , Figure 3 A schematic diagram of a fingerprint acquisition circuit according to an embodiment of the present disclosure is shown.

[0091] In one example, such as Figure 3 As shown, the first end (1) of each third control switch 131 is connected to the output end of the corresponding signal processing module 20, the second end (2) of each third control switch 131 is connected to the arithmetic module 30, and the control end of each third control switch 131 is used to receive the first control signal SEL.

[0092] In one example, the touch signal output by the target pixel unit (such as pixel unit p00) is processed by the processing module to obtain a digital touch signal that can be directly output to the arithmetic module. The digital touch signals of the other pixel units besides the target pixel unit are transmitted to the arithmetic module 30 through each third control switch 131.

[0093] In one example, when the selection signal SEL has a first level state, the first and second terminals of the third control switch 131 are connected to form a transmission channel, allowing the arithmetic module 30 to receive the digital touch signal from the digital signal processing module through this transmission channel, i.e., as shown below. Figure 2 As shown, the touch signal of pixel unit p00 is converted into digital signal Vout00 by processing module 20, the touch signal of pixel unit p01 is converted into digital signal Vout01 by processing module 20, the touch signal of pixel unit p10 is converted into digital signal Vout00 by processing module 20, and the touch signal of pixel unit p11 is converted into digital signal Vout1 by processing module 20. These signals are then transmitted to the calculation module 30 for calculation to obtain a fingerprint image.

[0094] In one example, when the selection signal SEL has a second level state, the first and second terminals of the third control switch 131 are disconnected, and the transmission channel is disconnected. In this case, as follows: Figure 2 As shown, pixel units p00, p01, p10, and p11 are connected in parallel. Thus, the parallel touch signals are converted into digital signals Vout00 by the processing module 20 and directly transmitted to the arithmetic module 30 for related calculations.

[0095] Of course, the number of signal processing modules 20 can also include only one. The following is an example of this situation and its implementation.

[0096] In one example, the pixel units of the pixel module in this embodiment of the present disclosure may share a single signal processing module 20 to reduce the cost of the fingerprint acquisition circuit.

[0097] In one possible implementation, the switch module 10 may further include a second switch unit 120, which may include a plurality of second control switches 121. Each second control switch 121 includes a plurality of connection terminals, and the second control switches 121 are distributed in a multi-level manner.

[0098] The first end of each of the first-level second control switches 121 is connected to the second end of the corresponding first control switch 111, the second end of each of the second control switches 121 is connected to the third end of the second control switch 121 of the next level, the third end of each of the second control switches 121 is connected to the second end of another corresponding first control switch 111 or the output end of the target pixel unit, and the first control switches 111 connected to the first ends of each of the second control switches 121 are different.

[0099] One or more second-level second control switches 121 have their first terminals connected to the second terminals of the corresponding second control switches 121 in the previous level, and their third terminals are connected to the second terminals of another corresponding second control switch 121 in the previous level.

[0100] Among them, the second control switches 121 connected to the first and third ends of each second control switch 121 are different;

[0101] The second terminal of the last second-level second control switch 121 is connected to the signal processing module 20.

[0102] In one possible implementation, each level of the second control switch 121 is used to receive the second control signal of each level, so as to output the touch signal of any pixel unit or the touch signal of multiple pixel units connected in parallel to the signal processing module 20, wherein the number of the signal processing modules 20 is 1.

[0103] In one possible implementation, when the pixel module is an n×n pixel array, the second switching unit 120 includes n stages, and the second switching unit 120 includes 2 stages. n -1 second control switches 121, the i-th level includes i second control switches 121, where i and n are both positive integers greater than 1 and i≤n, and the n-th level is the first level.

[0104] In this embodiment of the present disclosure, by controlling each of the second control switches 121 of the second switch unit, a processing module 20, namely an analog signal processing unit 210 and an analog-to-digital conversion unit 220, is used to process the touch signals or parallel touch signals output by each pixel unit in the pixel module to obtain digital touch signals, thereby reducing costs and simplifying the circuit structure.

[0105] Please see Figure 4 , Figure 4 A schematic diagram of a fingerprint acquisition circuit according to an embodiment of the present disclosure is shown.

[0106] In one example, such as Figure 4As shown, for a 2×2 pixel array, the second switching unit 120 of this embodiment includes two levels of control switches (n=2), and the second switching unit 120 includes three second control switches 121. The first level (the last second level) includes one second control switch 121, and the second level (corresponding to the first level) includes two second control switches.

[0107] In one example, such as Figure 4 As shown, the first end of each second control switch 121 in the second level is connected to the second end of the corresponding first control switch 111. For example, the first end of the first second control switch 121 is connected to the second end of the first control switch 111 corresponding to pixel unit p01 (2); the second end of each second control switch 121 is connected to the third end of the second control switch 121 in the next level. For example, the second end of the first second control switch 121 is connected to the third end of the second control switch in the first level; the third end of each second control switch 121 is connected to the second end of another corresponding first control switch 111 or the output end of the target pixel unit. For example, the third end of the first second control switch 121 is connected to the output end of the target pixel unit p00, and the third end of the second second control switch 121 is connected to the second end of the first control switch 111 corresponding to pixel unit p10.

[0108] In one example, such as Figure 4 As shown, the first control switches 111 connected to the first terminals of each second control switch 121 are different, and it should be understood that the connection terminals of each second stage of the subsequent stage are also different from the second control switches 121 connected to the second stage of the preceding stage.

[0109] In one example, such as Figure 4 As shown, the control signals of the second control switches at each level are independent. For example, the second control switch of the first level is controlled by SEL[0], the two second control switches of the second level are controlled by SEL[1], and each first control switch 111 of the first switch unit 110 is controlled by SEL[2]. That is, the control signal is SEL[2:0]. Each corresponding bit controls each first control switch 111 of the first switch unit 110 and each level of the second control switch in the second switch unit 120.

[0110] In one example, such as Figure 4 As shown, when the control signal is SEL[2:0] = 3'b100, the touch signal of pixel unit p00 is converted into digital signal Vout by signal processing module 20.

[0111] In one example, such as Figure 4As shown, when the control signal SEL[2:0] = 3'b110, the touch signal of pixel unit p01 is converted into digital signal Vout by signal processing module 20.

[0112] In one example, such as Figure 4 As shown, when the control signal SEL[2:0] = 3'b101, the touch signal of pixel unit p10 is converted into digital signal Vout by signal processing module 20.

[0113] In one example, such as Figure 4 As shown, when the control signal SEL[2:0] = 3'b111, the touch signal of pixel unit p11 is converted into digital signal Vout by signal processing module 20.

[0114] In one example, such as Figure 4 As shown, when the control signal SEL[2:0] = 3'b000, the touch signals of the four pixel units p00, p01, p10 and p11 connected in parallel are converted into digital signal Vout by the signal processing module 20.

[0115] In one example, such as Figure 4 As shown, when the control signal SEL[2:0] = 3'b001, 3'b010 or 3'b011, the four pixel units p00, p01, p10 and p11 (that is, the 2×2 sensing capacitors 21 in the pixel module) are in a floating state.

[0116] Of course, the switch module 10 of this embodiment may also include other modes.

[0117] In one possible implementation, the switch module 10 further includes a fourth switch unit 140, which includes a plurality of fourth control switches 141, each of which includes a plurality of connection terminals.

[0118] The first terminal of each fourth control switch 141 is connected to the output terminal of the corresponding pixel unit, and the second terminal of each fourth control switch 141 is connected to the signal processing module 20. The first control terminal of each fourth control switch 141 is used to receive row control signals, and the second control terminal of each fourth control switch 141 is used to receive column control signals.

[0119] The row control signal and the column control signal are used to determine the switching state of each fourth control switch 141.

[0120] In one possible implementation, when both the row control signal and the column control signal are valid, each of the fourth control switches 141 is turned on, and the touch signal is generated after multiple pixel units are connected in parallel.

[0121] Through the fourth switching unit, the embodiments of this disclosure can use row control signals and column control signals to select the corresponding pixel unit to output touch signals, thereby enabling multiple pixel units to be turned on at the same time to adapt to the needs of various DPI scenarios.

[0122] Please see Figure 5 , Figure 5 A schematic diagram of a fingerprint acquisition circuit according to an embodiment of the present disclosure is shown.

[0123] In one example, such as Figure 5 As shown, a pixel module can include a 3×3 pixel unit array.

[0124] In one example, such as Figure 5 As shown, in a pixel module containing 3×3 pixel units, j×k (i.e., 3×3) of the pixel units are connected to the signal processing module through j×k of the fourth control switches 141.

[0125] In one example, such as Figure 5 As shown, each of the fourth control switches 141 has a first terminal (1), a second terminal (2), a first control terminal (3), and a second control terminal (4). The first terminal is coupled to the pixel unit, for example, the first terminal of the first fourth control switch 141 is connected to the output terminal of the pixel unit p00; the second terminal is coupled to the processing module, for example, the second terminal of the first fourth control switch 141 is connected to the processing module; the first control terminal is coupled to the first selection signal Col, and the second control terminal is coupled to the second selection signal Row.

[0126] In one example, such as Figure 5 As shown, multiple fourth control switches 141 are coupled to N row control signals Col and M column control signals Row. When both the row control signal Col and the column control signal Row are valid, for example, when both have a first level state (e.g., SEL=1), a channel is formed inside the fourth control switch 141, allowing the processing module to receive the touch signal from the pixel module through this channel.

[0127] In one example, when both the row control signal Col and the column control signal Row are invalid or either one is invalid, for example, both or either one has a first level state (e.g., SEL=0), the channel inside the fourth control switch 141 is closed.

[0128] Please see Figure 6 , Figure 6A control timing diagram of a fourth switching unit according to an embodiment of the present disclosure is shown.

[0129] In one example, such as Figure 6 As shown, the embodiments of this disclosure can partially or completely drive the pixel units of each pixel module by changing the level state and width of the pulses of each column control signal and each row control signal. In this way, the fingerprint acquisition circuit of the embodiments of this disclosure can support the simultaneous activation of multiple pixel units for fingerprint signal acquisition, thereby effectively increasing the amount of fingerprint signal and achieving the beneficial effects of reducing the processing difficulty of fingerprint unlocking algorithms and improving the applicability of various DPI application scenarios.

[0130] The following provides an example of possible implementations of the signal processing module.

[0131] Please see Figure 7 , Figure 7 A schematic diagram of a signal processing module according to an embodiment of the present disclosure is shown.

[0132] In one possible implementation, such as Figure 7 As shown, the signal processing module 20 may include:

[0133] The analog signal processing unit 210 is used to process the received touch signal and output the processed touch signal.

[0134] The analog-to-digital conversion unit 220, connected to the analog signal processing unit 210, is used to perform analog-to-digital conversion on the processed touch signal to obtain a digital touch signal.

[0135] The number of the analog signal processing unit 210 and the analog-to-digital conversion unit 220 is one or more.

[0136] In one possible implementation, such as Figure 7 As shown, the analog signal processing unit 210 includes a processing switch 211, an adjustable capacitor 212, and an operational amplifier 213, wherein...

[0137] The positive input terminal of the operational amplifier 213 is connected to the first terminal of the processing switch 211 and the first terminal of the adjustable capacitor 212, and is used to receive the touch signal; the negative input terminal is used to input a reference signal.

[0138] The second terminal of the processing switch 211 is connected to the second terminal of the adjustable capacitor 212 and the output terminal of the operational amplifier 213.

[0139] In one possible implementation, such as Figure 7As shown, the analog-to-digital conversion unit 220 includes a first conversion switch 221, a second conversion switch 222, a first conversion capacitor 223, a second conversion capacitor 224, and an analog-to-digital converter 225, wherein...

[0140] The first terminals of the first switch 221 and the second switch 222 are connected to the output terminal of the analog signal processing unit 210 for receiving the processed touch signal.

[0141] The second terminal of the first changeover switch is connected to the first terminal of the first conversion capacitor 223 and the positive input terminal of the analog-to-digital converter 225, and the second terminal of the second changeover switch is connected to the first terminal of the second conversion capacitor 224 and the negative input terminal of the analog-to-digital converter 225.

[0142] The output of the analog-to-digital converter 225 is used to output the digital touch signal.

[0143] The embodiments disclosed herein do not limit the specific implementation of the analog signal processing unit 210 and the analog-to-digital conversion unit 220. The above description is exemplary. Those skilled in the art can use related technologies to implement front-end processing of analog touch signals, such as amplification and filtering, and can use related technologies to implement digital-to-analog conversion of analog touch signals.

[0144] The embodiments of this disclosure do not limit the type of each switch. Each switch in the embodiments of this disclosure can be implemented by a metal-oxide-semiconductor field-effect transistor (MOSFET), an insulated gate bipolar transistor (IGBT), or other types of switches. For example, it can include CMOS (Complementary Metal-Oxide-Semiconductor), NMOS (N-Metal-Oxide-Semiconductor), PMOS (P-Metal-Oxide-Semiconductor), etc., or other types of transistors.

[0145] The present disclosure does not limit the specific implementation of generating switch control signals. In one example, the present disclosure may include a pulse width modulation circuit to generate a pulse width modulation (PWM) signal to control each switch. Of course, other signal generation circuits may also be used to generate corresponding control signals.

[0146] The computing module of this disclosure may include a processing component, which includes, but is not limited to, a separate processor, discrete components, or a combination of a processor and discrete components. The processor may include a controller in an electronic device with instruction execution capabilities. The processor may be implemented in any suitable manner, for example, by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components. Within the processor, the executable instructions may be executed by hardware circuits such as logic gates, switches, ASICs, programmable logic controllers, and embedded microcontrollers.

[0147] This disclosure does not limit the specific operations performed by the arithmetic module 30. Those skilled in the art can use related technologies to realize fingerprint recognition using digital touch signals, as well as other subsequent functions (such as fingerprint unlocking, security authentication, etc.).

[0148] According to one aspect of this disclosure, a chip is provided, the chip including the fingerprint acquisition circuit described above.

[0149] According to one aspect of this disclosure, an electronic device is provided, the electronic device including the chip described above.

[0150] In one possible implementation, the electronic device includes a display, a smartphone, or a portable device.

[0151] The display in this disclosure may include a liquid crystal display panel, an organic light-emitting diode display panel, a quantum dot light-emitting diode display panel, a mini light-emitting diode display panel, and a micro light-emitting diode display panel, etc.

[0152] The electronic devices disclosed in this embodiment are also referred to as user equipment (UE), mobile station (MS), mobile terminal (MT), etc., and are devices that provide voice and / or data connectivity to users. Examples include handheld devices and in-vehicle devices with wireless connectivity. Currently, some examples of terminals include: mobile phones, tablets, laptops, PDAs, mobile internet devices (MID), wearable devices, virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, and wireless terminals in vehicle-to-everything (V2X) networks.

[0153] Figure 8 A block diagram of an electronic device according to an embodiment of the present disclosure is shown.

[0154] For example, electronic device 800 can be a mobile phone, computer, digital broadcasting terminal, messaging device, game console, tablet device, medical device, fitness equipment, personal digital assistant, and other terminals.

[0155] Reference Figure 8 The electronic device 800 may include one or more of the following components: a processing component 802, a memory 804, a power supply component 806, a multimedia component 808, an audio component 810, an input / output (I / O) interface 812, a sensor component 814, and a communication component 816.

[0156] Processing component 802 typically controls the overall operation of electronic device 800, such as operations associated with display, telephone calls, data communication, camera operation, and recording operations. Processing component 802 may include one or more processors 820 to execute instructions to complete all or part of the steps of the methods described above. Furthermore, processing component 802 may include one or more modules to facilitate interaction between processing component 802 and other components. For example, processing component 802 may include a multimedia module to facilitate interaction between multimedia component 808 and processing component 802.

[0157] Memory 804 is configured to store various types of data to support the operation of electronic device 800. Examples of this data include instructions for any application or method operating on electronic device 800, contact data, phonebook data, messages, pictures, videos, etc. Memory 804 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0158] Power supply component 806 provides power to various components of electronic device 800. Power supply component 806 may include a power management system, one or more power supplies, and other components associated with generating, managing, and distributing power to electronic device 800.

[0159] Multimedia component 808 includes a screen that provides an output interface between the electronic device 800 and the user. In some embodiments, the screen may include a liquid crystal display (LCD) and a touch panel (TP). If the screen includes a touch panel, the screen may be implemented as a touchscreen to receive input signals from the user. The touch panel includes one or more touch sensors to sense touches, swipes, and gestures on the touch panel. The touch sensors may sense not only the boundaries of the touch or swipe action but also the duration and pressure associated with the touch or swipe operation. In some embodiments, multimedia component 808 includes a front-facing camera and / or a rear-facing camera. When the electronic device 800 is in an operating mode, such as a shooting mode or a video mode, the front-facing camera and / or the rear-facing camera may receive external multimedia data. Each front-facing camera and rear-facing camera may be a fixed optical lens system or have focal length and optical zoom capabilities.

[0160] Audio component 810 is configured to output and / or input audio signals. For example, audio component 810 includes a microphone (MIC) configured to receive external audio signals when electronic device 800 is in an operating mode, such as call mode, recording mode, and voice recognition mode. The received audio signals may be further stored in memory 804 or transmitted via communication component 816. In some embodiments, audio component 810 also includes a speaker for outputting audio signals.

[0161] I / O interface 812 provides an interface between processing component 802 and peripheral interface modules, such as keyboards, click wheels, buttons, etc. These buttons may include, but are not limited to, home buttons, volume buttons, power buttons, and lock buttons.

[0162] Sensor assembly 814 includes one or more sensors for providing state assessments of various aspects of electronic device 800. For example, sensor assembly 814 may detect the on / off state of electronic device 800, the relative positioning of components such as the display and keypad of electronic device 800, changes in position of electronic device 800 or a component of electronic device 800, the presence or absence of user contact with electronic device 800, orientation or acceleration / deceleration of electronic device 800, and temperature changes of electronic device 800. Sensor assembly 814 may include a proximity sensor configured to detect the presence of nearby objects without any physical contact. Sensor assembly 814 may also include an optical sensor, such as a complementary metal-oxide-semiconductor (CMOS) or charge-coupled device (CCD) image sensor, for use in imaging applications. In some embodiments, sensor assembly 814 may also include an accelerometer, gyroscope, magnetometer, pressure sensor, or temperature sensor.

[0163] Communication component 816 is configured to facilitate wired or wireless communication between electronic device 800 and other devices. Electronic device 800 can access wireless networks based on communication standards, such as WiFi, second-generation mobile communication technology (2G), or third-generation mobile communication technology (3G), or combinations thereof. In one exemplary embodiment, communication component 816 receives broadcast signals or broadcast-related information from an external broadcast management system via a broadcast channel. In one exemplary embodiment, communication component 816 also includes a near-field communication (NFC) module to facilitate short-range communication. For example, the NFC module may be implemented based on radio frequency identification (RFID) technology, Infrared Data Association (IrDA) technology, ultra-wideband (UWB) technology, Bluetooth (BT) technology, and other technologies.

[0164] Various aspects of the embodiments of this disclosure, through the switching control of the switching module, can realize the output of touch signals from any one pixel unit in the corresponding pixel module or the touch signal from multiple pixel units connected in parallel, to support fingerprint signal acquisition at various DPIs. Based on different DPI scenarios, the number of pixel units included in the pixel module is determined as needed, and multiple pixel units are activated to increase the amount of fingerprint signal, improve fingerprint acquisition speed, and reduce the complexity of fingerprint processing, thereby improving fingerprint recognition efficiency. The embodiments of this disclosure can support the simultaneous activation of multiple pixel units for fingerprint signal acquisition, thereby effectively increasing the amount of fingerprint signal and achieving the beneficial effect of reducing the processing difficulty of fingerprint unlocking algorithms.

[0165] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A fingerprint acquisition circuit, characterized in that, This circuit is used to acquire fingerprints from a fingerprint sensing component comprising multiple pixel units, wherein the pixel units are used to generate corresponding touch signals in response to touch of a target object. The circuit includes multiple switching modules, a signal processing module, and a computation module, wherein: Each switch module corresponds to a pixel module, and each pixel module includes any number of pixel units in the fingerprint sensing component. The switch module is used to output the touch signal of any one pixel unit in the corresponding pixel module or the touch signal of multiple pixel units connected in parallel. The signal processing module is used to process the received touch signal to obtain a digital touch signal; The computing module is used to process the digital touch signal to obtain a fingerprint image. The switch module further includes a fourth switch unit, which includes multiple fourth control switches, each of which includes multiple connection terminals. The first terminal of each fourth control switch is connected to the output terminal of the corresponding pixel unit, and the second terminal of each fourth control switch is connected to the signal processing module. The first control terminal of each fourth control switch is used to receive row control signals, and the second control terminal of each fourth control switch is used to receive column control signals. The row control signal and the column control signal are used to determine the switching state of each fourth control switch. When both the row control signal and the column control signal are valid, each of the fourth control switches is turned on, and the touch signal is generated after multiple pixel units are connected in parallel.

2. The circuit according to claim 1, characterized in that, Each pixel unit includes a sensing capacitor, and the touch signal obtained by connecting the multiple pixel units in parallel is the signal output by connecting the sensing capacitors of the multiple pixel units in parallel.

3. The circuit according to claim 1, characterized in that, The switch module includes a first switch unit, which includes a plurality of first control switches, each of which includes a plurality of connection terminals. Each first control switch has its first terminal connected to the output terminal of its corresponding pixel unit, its second terminal connected to the signal processing module, and its third terminal connected to the output terminal of the target pixel unit. Each first control switch's control terminal is used to receive a first control signal. The output terminal of the target pixel unit is connected to the signal processing module. The target pixel unit is one of the pixel units in the pixel module.

4. The circuit according to claim 3, characterized in that, The first control signal is used to enable the connection between the first terminal and the second terminal of each first control switch to form a first channel, or to enable the connection between the first terminal and the third terminal of each first control switch to form a second channel. When the first channel is active, the touch signal of each pixel unit is output to the signal processing module. When the second channel is active, the touch signal of each pixel unit connected in parallel is output to the signal processing module.

5. The circuit according to claim 3 or 4, characterized in that, The switch module further includes a second switch unit, which includes multiple second control switches. Each second control switch has multiple connection terminals, and the second control switches are distributed in a multi-level manner. The first terminal of each second control switch in the first stage is connected to the second terminal of the corresponding first control switch, the second terminal of each second control switch is connected to the third terminal of the second control switch in the next stage, and the third terminal of each second control switch is connected to the second terminal of another corresponding first control switch or the output terminal of the target pixel unit. The first control switches connected to the first terminals of each second control switch are different. One or more second-level control switches have their first terminals connected to the second terminals of their corresponding second-level control switches in the previous level, and their third terminals are connected to the second terminals of another corresponding second-level control switch in the previous level. Among them, the second control switches connected to the first and third ends of each second control switch are different; The second terminal of the last second-level second control switch is connected to the signal processing module.

6. The circuit according to claim 5, characterized in that, Each level of the second control switch is used to receive the second control signal of each level, so as to output the touch signal of any pixel unit or the touch signal of multiple pixel units connected in parallel to the signal processing module, wherein the number of the signal processing modules is 1.

7. The circuit according to claim 5, characterized in that, When the pixel module is an n×n pixel array, the second switching unit includes n stages, and the second switching unit includes 2 stages. n -1 second control switches, the i-th level includes i second control switches, where i and n are both positive integers greater than 1 and i≤n, and the n-th level is the first level.

8. The circuit according to claim 3 or 4, characterized in that, The number of signal processing modules includes multiple modules, each connected to the output terminal of a respective switch module. Each switch module also includes a third switch unit disposed between the signal processing modules and the arithmetic module. The third switch unit includes multiple third control switches, each with multiple connection terminals. The first terminal of each third control switch is connected to the output terminal of the corresponding signal processing module, the second terminal of each third control switch is connected to the arithmetic module, and the control terminal of each third control switch is used to receive the first control signal. The first control signal is also used to control the conduction state of each third control switch.

9. The circuit according to claim 1, characterized in that, The signal processing module includes: The analog signal processing unit is used to process the received touch signals and output the processed touch signals. An analog-to-digital conversion unit, connected to the analog signal processing unit, is used to perform analog-to-digital conversion on the processed touch signal to obtain a digital touch signal. The number of the analog signal processing unit and the analog-to-digital conversion unit is one or more.

10. The circuit according to claim 9, characterized in that, The analog signal processing unit includes a processing switch, an adjustable capacitor, and an operational amplifier, wherein... The positive input terminal of the operational amplifier is connected to the first terminal of the processing switch and the first terminal of the adjustable capacitor to receive the touch signal, and the negative input terminal is used to input a reference signal. The second terminal of the processing switch is connected to the second terminal of the adjustable capacitor and the output terminal of the operational amplifier.

11. The circuit according to claim 9 or 10, characterized in that, The analog-to-digital conversion unit includes a first conversion switch, a second conversion switch, a first conversion capacitor, a second conversion capacitor, and an analog-to-digital converter, wherein... The first terminal of the first switch and the second switch are connected to the output terminal of the analog signal processing unit to receive the processed touch signal. The second terminal of the first switching switch is connected to the first terminal of the first switching capacitor and the positive input terminal of the analog-to-digital converter, and the second terminal of the second switching switch is connected to the first terminal of the second switching capacitor and the negative input terminal of the analog-to-digital converter. The output of the analog-to-digital converter is used to output the digital touch signal.

12. A chip, characterized in that, The chip includes a fingerprint acquisition circuit as described in any one of claims 1-11.

13. An electronic device, characterized in that, The electronic device includes the chip as described in claim 12.

14. The electronic device according to claim 13, characterized in that, The electronic device includes a display, a smartphone, or a portable device.

Images