Fingerprint device wake-up circuit and fingerprint device

Abstract

The present invention belongs to the field of fingerprint identification technology, and provides a fingerprint device wake-up circuit and a fingerprint device. It includes a fingerprint sensing module, a first switch circuit, a second switch circuit, a touch scanning circuit, a fingerprint scanning circuit and a controller. The multiplexed electrode generates a first sensing signal according to the user input, and the fingerprint sensing module generates a second sensing signal according to the user input. When the fingerprint device is in a waiting state, the controller controls the first switch circuit to connect the first sensing signal to the touch scanning circuit, and the touch scanning circuit generates a wake-up signal according to the first sensing signal. The controller generates a second switch signal according to the wake-up signal, controls the second switch circuit to connect the second sensing signal to the fingerprint scanning circuit, and the fingerprint scanning circuit obtains the fingerprint signal according to the second sensing signal, thereby realizing the collection of the fingerprint signal. Different scanning circuits are used to scan the device wake-up and fingerprint collection, and the multiplexed electrodes in the fingerprint sensing module are reused, which effectively reduces power consumption.

Description

Technical Field

[0001] The present invention belongs to the technical field of fingerprint identification, and in particular relates to a fingerprint device wake-up circuit and a fingerprint device. Background Art

[0002] With the development of technology, biometric identification is being used more and more widely in various fields. Capacitive biometric identification, especially capacitive fingerprint identification, is used in various electronic devices such as mobile phones, computers, and tablets. When an electronic device equipped with a capacitive fingerprint module is on standby, the scanning circuit needs to be in a "sleep-detection" timing detection cycle. Specifically, in order to complete the sleep wake-up function through capacitive detection, it is necessary to periodically scan the fingerprint sensing module array in the capacitive fingerprint module at the same frequency, which will generate higher power consumption. In particular, when the fingerprint module needs to respond quickly to fingerprint pressing, the frequency of timing detection is higher and the power consumption is also greater.

[0003] The existing fingerprint device touch wake-up solution is to set up a touch module and a touch chip separately. When the touch module senses the touch of a finger, the sensing result is transmitted to the touch chip, and then the fingerprint scanning circuit collects the fingerprint. The touch detection circuit includes a conductive signal medium that contacts the effective identification area, such as a metal ring or a metal shell. An additional touch detection structure needs to be set up, which increases the cost and power consumption. Summary of the invention

[0004] The object of the present invention is to provide a fingerprint device wake-up circuit and a fingerprint device, aiming to solve the problem that a touch detection structure needs to be additionally provided in a traditional fingerprint device wake-up solution, thereby increasing cost and power consumption.

[0005] A fingerprint device wake-up circuit, the fingerprint device wake-up circuit comprising: a fingerprint sensing module, a first switch circuit, a second switch circuit, a touch scanning circuit, a fingerprint scanning circuit and a controller;

[0006] The fingerprint sensing module includes a multiplexed electrode and a non-multiplexed electrode, the multiplexed electrode is configured to generate a first sensing signal according to a user input, and the fingerprint sensing module is configured to generate a second sensing signal according to a user input; the first switch circuit is connected between the touch scanning circuit and the multiplexed electrode, and the first switch circuit is configured to conduct the first sensing signal according to the first switch circuit signal; the second switch circuit is connected between the fingerprint scanning circuit and the fingerprint sensing module, and the second switch circuit is configured to conduct the second sensing signal according to the second switch signal; the touch scanning circuit is configured to generate a wake-up signal according to the first sensing signal, and the fingerprint scanning circuit generates a fingerprint signal according to the second sensing signal, and the controller is configured to generate the first switch circuit signal in the wake-up state or generate the first switch circuit signal according to the stop of the fingerprint signal, and generate the second switch signal according to the wake-up signal.

[0007] In one embodiment, the multiplexed electrode is specifically configured to generate the first sensing signal according to the user input and the first excitation signal, and the fingerprint sensing module is specifically configured to generate the second sensing signal according to the user input and the second excitation signal;

[0008] The fingerprint device wake-up circuit also includes a signal generating circuit connected to the fingerprint sensing module and used to generate the first excitation signal and the second excitation signal.

[0009] In one embodiment, the signal generating circuit is specifically configured to generate the first excitation signal according to a first control signal, and to generate the second excitation signal according to a second control signal;

[0010] The controller is further configured to generate the first control signal in the wake-up state or generate the first control signal according to the cessation of the fingerprint signal, and generate the second control signal according to the wake-up signal. In one embodiment, the first electrode plate of at least one of the multiplexed electrodes is connected to the touch scanning circuit and the fingerprint scanning circuit, and the second electrode plate of the multiplexed electrode is grounded, and / or the first electrode plate of at least one of the non-multiplexed electrodes is connected to the fingerprint scanning circuit, and the second electrode plate of the non-multiplexed electrode is grounded.

[0011] In one embodiment, the distance between two adjacent multiplexing electrodes is smaller than a first preset value.

[0012] In one embodiment, the touch scanning circuit includes a first amplifier, a first comparison unit and a first capacitor; the inverting end of the first amplifier is the first sensing signal input end of the touch scanning circuit, the non-phase end of the first amplifier is connected to the first reference voltage, the output end of the first amplifier is connected to the input end of the first comparison unit, the output end of the first comparison unit serves as the wake-up signal output end of the touch scanning circuit, and the first capacitor is connected between the inverting end of the first amplifier and the output end of the first amplifier.

[0013] In one embodiment, the fingerprint scanning circuit includes a second amplifier, a second comparison unit and a second capacitor; the inverting end of the second amplifier is the second sensing signal input end of the fingerprint scanning circuit, the non-phase end of the second amplifier is connected to the first reference voltage, the output end of the second amplifier is connected to the input end of the second comparison unit, the output end of the second comparison unit serves as the fingerprint signal output end of the fingerprint scanning circuit, and the second capacitor is connected between the inverting end of the second amplifier and the output end of the second amplifier.

[0014] In one embodiment, the second comparison unit outputs different fingerprint signals according to different signal inputs.

[0015] In one of the embodiments, a scanning frequency of the touch scanning circuit is lower than a scanning frequency of the fingerprint scanning circuit.

[0016] In addition, a fingerprint device is provided, and the fingerprint device includes: the above-mentioned fingerprint device wake-up circuit.

[0017] The above-mentioned fingerprint device wake-up circuit includes a fingerprint sensing module, a first switch circuit, a second switch circuit, a touch scanning circuit, a fingerprint scanning circuit and a controller. The reused electrode generates a first sensing signal according to the user input, and the fingerprint sensing module generates a second sensing signal according to the user input. When the fingerprint device is in a dormant or touch-ready state, the controller controls the first switch circuit to connect the first sensing signal to the touch scanning circuit, and the touch scanning circuit generates a wake-up signal according to the first sensing signal. The controller generates a second switch signal according to the wake-up signal, controls the second switch circuit to connect the second sensing signal to the fingerprint scanning circuit, and the fingerprint scanning circuit obtains the fingerprint signal according to the second sensing signal, thereby realizing the collection of fingerprint signals. Different scanning circuits are used to scan the device wake-up and fingerprint collection, and the reused electrodes in the fingerprint sensing module are reused, which effectively reduces power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the structure of a fingerprint device wake-up circuit provided in an embodiment of the present invention;

[0019] Figure 2 A schematic diagram of the structure of a fingerprint device wake-up circuit provided by another embodiment of the present invention;

[0020] Figure 3 for Figure 2 The circuit schematic diagram of the fingerprint device wake-up circuit shown;

[0021] Figure 4 A circuit schematic diagram of a fingerprint device wake-up circuit provided by another embodiment of the present invention;

[0022] Figure 5 for Figure 1 The diagram shows the electrode arrangement of the fingerprint sensing module in the fingerprint device wake-up circuit. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0024] Figure 1 FIG. 2 shows a schematic diagram of a fingerprint device wake-up circuit provided by a preferred embodiment of the present invention. Figure 1 As shown, an embodiment of the present invention provides a fingerprint device wake-up circuit, which includes a fingerprint sensing module 10, a first switch circuit 20, a second switch circuit 30, a touch scanning circuit 40, a fingerprint scanning circuit 50 and a controller 60; the fingerprint sensing module 10 includes a reused electrode 11 and a non-reuse electrode 12, the reused electrode 11 is configured to generate a first sensing signal according to a user input, and the fingerprint sensing module 10 is configured to generate a second sensing signal according to the user input; the first switch circuit 20 is connected between the touch scanning circuit 40 and the reused electrode 11, and the first switch circuit 20 is configured to conduct the first sensing signal according to the signal of the first switch circuit 20; the second switch circuit 30 is connected between the fingerprint scanning circuit 50 and the fingerprint sensing module 10, and the second switch circuit 30 is configured to conduct the second sensing signal according to the second switch signal; the touch scanning circuit 40 is configured to generate a wake-up signal according to the first sensing signal, the fingerprint scanning circuit 50 generates a fingerprint signal according to the second sensing signal, and the controller 60 is configured to generate a first switch signal in the waiting state or generate a first switch signal according to the stop of the fingerprint signal, and generate a second switch signal according to the wake-up signal.

[0025] In this embodiment, the reused electrode 11 generates a first sensing signal according to the user input, and the fingerprint sensing module 10 generates a second sensing signal according to the user input. When the fingerprint device is in a dormant or touch-ready state, the controller 60 controls the first switch circuit 20 to connect the first sensing signal to the touch scanning circuit 40, and the touch scanning circuit 40 generates a wake-up signal according to the first sensing signal. The controller 60 generates a second switch signal according to the wake-up signal, controls the second switch circuit 30 to connect the second sensing signal to the fingerprint scanning circuit 50, and the fingerprint scanning circuit 50 obtains the fingerprint signal according to the second sensing signal, thereby realizing the collection of the fingerprint signal. Different scanning circuits are used to scan the device wake-up and fingerprint collection, and the reused electrode 11 is reused, which effectively reduces power consumption.

[0026] like Figure 1 As shown, in this embodiment, when the fingerprint device is in a sleep or touch-ready state, the first switch circuit 20 is turned on, the second switch circuit 30 is turned off, the multiplexed electrode 11 is connected to the touch scanning circuit 40, and the multiplexed electrode 11 is scanned at a first scanning frequency by the touch scanning circuit 40 to obtain a first sensing signal. When the first sensing signal is greater than a first preset value, the touch scanning circuit 40 generates a wake-up signal to the controller 60. The controller 60 determines that there is a touch event and generates a second switch signal to control the first switch circuit 20 to turn off, the second switch circuit 30 is turned on, all the sensing electrodes in the fingerprint sensing module 10 are connected to the fingerprint scanning circuit 50, and all the sensing electrodes in the fingerprint sensing module 10 are scanned at a second scanning frequency by the fingerprint scanning circuit 50 to obtain a second sensing signal. The fingerprint scanning circuit 50 generates a fingerprint signal according to the second sensing signal to obtain fingerprint information.

[0027] like Figure 2As shown, in one embodiment, the multiplexed electrode 11 is specifically configured to generate a first sensing signal according to a user input and a first excitation signal, and the fingerprint sensing module 10 is specifically configured to generate a second sensing signal according to a user input and a second excitation signal; the fingerprint device wake-up circuit also includes a signal generating circuit 70 connected to the fingerprint sensing module 10 for generating a first excitation signal and a second excitation signal. Part of the sensing electrodes in the fingerprint sensing module 10 serve as receiving electrodes and the other part as transmitting electrodes. In this embodiment, some of the receiving electrodes serve as the multiplexed electrode 11. Specifically, both the first excitation signal and the second excitation signal can be scanning signals, the first excitation signal is only sent to some of the transmitting electrodes, and the second excitation signal is sent to all of the transmitting electrodes, wherein the scanning frequency of the first excitation signal is lower than the scanning frequency of the second excitation signal. In this embodiment, some of the receiving electrodes serve as the multiplexed electrode 11. Specifically, in the dormant or touch-ready state, the signal generating circuit 70 generates a first excitation signal, and the touch scanning circuit 40 scans the charge changes between the multiplexed electrode 11 and the transmitting electrode on the multiplexed electrode 11. As shown Figure 5 As shown, in the optional scanning order, the multiplexed electrode RX0 can be scanned for the first time, the multiplexed electrode RX2 can be scanned for the second time, the multiplexed electrode RXi can be scanned for the i-th time, ..., the multiplexed electrode RXn can be scanned for the n-th time, and after one round of scanning, the multiplexed electrode RX0, the multiplexed electrode RX2, the multiplexed electrode RXi, ..., the multiplexed electrode RXn can be scanned in sequence, wherein the first sensing signal at the first scanning is the charge change corresponding to D0, wherein the first sensing signal at the second scanning is the charge change corresponding to D1, wherein the first sensing signal at the i-th scanning is the charge change corresponding to D3, ..., the first sensing signal at the n-th scanning is the charge change corresponding to Dn, and the multiplexed electrodes 11 can be evenly distributed or unevenly distributed in the entire receiving electrode array. In the touch scanning mode, when the user has a touch action, the charge amount on the multiplexed electrode 11 in the contact area changes, and the multiplexed electrode 11 generates a first sensing signal. Similarly, in the fingerprint scanning mode, when the user has a finger pressing action, the charge amount on the receiving electrode in the contact area changes, and the receiving electrode generates a second sensing signal.

[0028] like Figure 2 and Figure 3 As shown, in one embodiment, the signal generating circuit 70 is specifically configured to generate a first excitation signal according to a first control signal, and to generate a second excitation signal according to a second control signal; the controller 60 is also configured to generate a first control signal in a wake-up state or to generate a first control signal according to the stopping of a fingerprint signal, and to generate a second control signal according to the wake-up signal.

[0029] like Figure 4As shown, in one embodiment, the first electrode plate of the multiplexed electrode 11 is connected to the touch scanning circuit and the fingerprint scanning circuit, the second electrode plate of the multiplexed electrode 11 is grounded, and / or the first electrode plate of at least one non-multiplexed electrode 12 is connected to the fingerprint scanning circuit, and the second electrode plate of the non-multiplexed electrode 12 is grounded. In this embodiment, the second electrode plate of the multiplexed electrode 11 and / or the second electrode plate of the non-multiplexed electrode 12 is connected to the power ground. A self-capacitance is formed between the first electrode plate of the multiplexed electrode 11 and the second electrode plate (power ground) of the multiplexed electrode 11, and a self-capacitance is formed between the first electrode plate of the non-multiplexed electrode 12 and the second electrode plate (power ground) of the non-multiplexed electrode 12. On this basis, the first electrode plate of the multiplexed electrode 11 or the first electrode plate of the non-multiplexed electrode 12 is scanned in sequence.

[0030] like Figure 5 As shown, in one embodiment, the distance between two adjacent reused electrodes 11 is less than a first preset value. Specifically, the fingerprint sensing module 10 includes a plurality of crisscrossed transmitting electrodes and a plurality of receiving electrodes, some of the sensing electrodes in the plurality of fingerprint sensing modules 10 serve as reused electrodes 11, the plurality of sensing electrodes include a plurality of crisscrossed transmitting electrodes and a plurality of receiving electrodes, some of the transmitting electrodes or some of the receiving electrodes serve as reused electrodes 11, and there is a first interval between two adjacent transmitting electrodes and two adjacent receiving electrodes. In order to ensure that the reused electrodes 11 can detect the user's touch action, the distance d1 between the reused electrodes 11 needs to be less than a first preset value, which is roughly the width of a finger.

[0031] like Figure 3 As shown, in one embodiment, the touch scanning circuit 40 includes a first amplifier U1, a first comparison unit U2 and a first capacitor C1; the inverting end of the first amplifier U1 is the first sensing signal input end of the touch scanning circuit 40, the positive end of the first amplifier U1 is connected to the first reference voltage, the output end of the first amplifier U1 is connected to the input end of the first comparison unit, the output end of the first comparison unit U2 is used as the wake-up signal output end of the touch scanning circuit 40, and the first capacitor C1 is connected between the inverting end of the first amplifier U1 and the output end of the first amplifier U1. In this embodiment, when the touch scanning circuit 40 is connected to the reused electrode 11, the reused electrode 11 is scanned, and the first sensing signal output by the reused electrode 11 is received. The first amplifier U1 amplifies the first sensing signal, and the amplified first sensing signal is compared with the first reference voltage through the first comparison unit U2. If the amplified first sensing signal is greater than the first reference voltage, it is determined that there is a touch action, and the first comparison unit U2 outputs a wake-up signal to the controller 60.

[0032] like Figure 3As shown, in one embodiment, the fingerprint scanning circuit 50 includes a second amplifier U3, a second comparison unit U3 and a second capacitor C2; the inverting end of the second amplifier U3 is the second sensing signal input end of the fingerprint scanning circuit 50, the non-inverting end of the second amplifier U3 is connected to the second reference voltage, the output end of the second amplifier U3 is connected to the input end of the second comparison unit, the output end of the second comparison unit is used as the fingerprint signal output end of the fingerprint scanning circuit 50, and the second capacitor C2 is connected between the inverting end of the second amplifier U3 and the output end of the second amplifier U3. In this embodiment, when the controller 60 receives the wake-up signal output by the touch scanning circuit 40, the controller 60 controls the fingerprint scanning circuit 50 to connect all the sensing electrodes, the fingerprint scanning circuit 50 scans all the sensing electrodes, and receives the second sensing signal output by the sensing electrodes, the second amplifier U3 amplifies the second sensing signal, and compares the amplified second sensing signal with the second reference voltage through the second comparison unit. If the amplified second sensing signal is greater than the second reference voltage, a fingerprint signal is generated, and the controller 60 records the fingerprint signal to generate fingerprint information.

[0033] like Figure 3 As shown, in one embodiment, the second comparison unit outputs different fingerprint signals according to different signal inputs. Specifically, the second comparison unit adopts a 10-bit successive approximation analog-to-digital converter structure, and the second comparison unit includes a digital-to-analog converter U4, a comparator U5, and a logic controller U6; the digital-to-analog converter U4 is connected to the second amplifier U3, and is configured to sample and hold the amplified second sensing signal to generate and hold the sampling signal, and the charge redistribution can be achieved by using the capacitor array cascade structure and switch control, and the sampling signal values ​​of different proportions can be output. The comparator U5 is connected to the digital-to-analog converter U4, and is configured to generate a fingerprint signal in binary form according to the comparison result of the sampling signal and the reference voltage. The logic controller U6 is connected to the digital-to-analog converter U4 and the comparator U5, and is configured to control the working timing of the digital-to-analog converter U4 and the comparator U5, and store and transfer the fingerprint signal.

[0034] In one embodiment, the scanning frequency of the touch scanning circuit 40 is less than the scanning frequency of the fingerprint scanning circuit 50. In this embodiment, the touch scanning circuit 40 uses a scanning circuit with a lower scanning frequency, and the fingerprint scanning circuit 50 uses a scanning circuit with a higher scanning frequency. In the touch scanning mode, the touch scanning circuit 40 scans the reused electrodes 11 at a lower frequency, and in the fingerprint scanning mode, the fingerprint scanning circuit 50 scans the sensing electrodes at a higher frequency. Different scanning circuits are used to scan device wake-up and fingerprint collection, and the reused electrodes 11 are reused, which effectively reduces power consumption.

[0035] On the basis of the above-mentioned fingerprint device wake-up circuit, the present application also provides a fingerprint device, which includes: the above-mentioned fingerprint device wake-up circuit. The reused electrode generates a first sensing signal according to the user input, and the fingerprint sensing module generates a second sensing signal according to the user input. When the fingerprint device is in a dormant or touch-ready state, the controller controls the first switch circuit to connect the first sensing signal to the touch scanning circuit, and the touch scanning circuit generates a wake-up signal according to the first sensing signal. The controller generates a second switch signal according to the wake-up signal, controls the second switch circuit to connect the second sensing signal to the fingerprint scanning circuit, and the fingerprint scanning circuit obtains the fingerprint signal according to the second sensing signal, thereby realizing the collection of fingerprint signals. Different scanning circuits are used to scan device wake-up and fingerprint collection, and the reused electrodes in the fingerprint sensing module are reused, which effectively reduces power consumption.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A fingerprint device wake-up circuit, characterized in that: The fingerprint device wake-up circuit includes: a fingerprint sensing module, a first switch circuit, a second switch circuit, a touch scanning circuit, a fingerprint scanning circuit and a controller; The fingerprint sensing module includes a multiplexed electrode and a non-multiplexed electrode, the multiplexed electrode is configured to generate a first sensing signal according to a user input, and the fingerprint sensing module is configured to generate a second sensing signal according to a user input; the first switch circuit is connected between the touch scanning circuit and the multiplexed electrode, and the first switch circuit is configured to conduct the first sensing signal according to the first switch circuit signal; the second switch circuit is connected between the fingerprint scanning circuit and the fingerprint sensing module, and the second switch circuit is configured to conduct the second sensing signal according to the second switch signal; the touch scanning circuit is configured to generate a wake-up signal according to the first sensing signal, and the fingerprint scanning circuit generates a fingerprint signal according to the second sensing signal, and the controller is configured to generate the first switch circuit signal in the waiting state or generate the first switch circuit signal according to the stop of the fingerprint signal, and generate the second switch signal according to the wake-up signal; The first electrode plate of at least one of the multiplexed electrodes is connected to the touch scanning circuit and the fingerprint scanning circuit, and the second electrode plate of the multiplexed electrode is grounded, and / or the first electrode plate of at least one of the non-multiplexed electrodes is connected to the fingerprint scanning circuit, and the second electrode plate of the non-multiplexed electrode is grounded; wherein a self-capacitance is formed between the first electrode plate of the multiplexed electrode and the second electrode plate of the multiplexed electrode, and a self-capacitance is formed between the first electrode plate of the non-multiplexed electrode and the second electrode plate of the non-multiplexed electrode.

2. The fingerprint device wake-up circuit according to claim 1, characterized in that: The multiplexed electrode is specifically configured to generate the first sensing signal according to the user input and the first excitation signal, and the fingerprint sensing module is specifically configured to generate the second sensing signal according to the user input and the second excitation signal; The fingerprint device wake-up circuit also includes a signal generating circuit connected to the fingerprint sensing module and used to generate the first excitation signal and the second excitation signal.

3. The fingerprint device wake-up circuit according to claim 2, characterized in that: The signal generating circuit is specifically configured to generate the first excitation signal according to the first control signal, and to generate the second excitation signal according to the second control signal; The controller is further configured to generate the first control signal in a waiting state or generate the first control signal according to the stopping of the fingerprint signal, and generate the second control signal according to the wake-up signal.

4. The fingerprint device wake-up circuit according to claim 1, characterized in that: The distance between two adjacent multiplexing electrodes is smaller than a first preset value.

5. The fingerprint device wake-up circuit according to claim 1, characterized in that: The touch scanning circuit includes a first amplifier, a first comparison unit and a first capacitor; the inverting end of the first amplifier is the first sensing signal input end of the touch scanning circuit, the non-phase end of the first amplifier is connected to the first reference voltage, the output end of the first amplifier is connected to the input end of the first comparison unit, the output end of the first comparison unit serves as the wake-up signal output end of the touch scanning circuit, and the first capacitor is connected between the inverting end of the first amplifier and the output end of the first amplifier.

6. The fingerprint device wake-up circuit according to claim 1, characterized in that: The fingerprint scanning circuit includes a second amplifier, a second comparison unit and a second capacitor; the inverting end of the second amplifier is the second sensing signal input end of the fingerprint scanning circuit, the non-phase end of the second amplifier is connected to the first reference voltage, the output end of the second amplifier is connected to the input end of the second comparison unit, the output end of the second comparison unit serves as the fingerprint signal output end of the fingerprint scanning circuit, and the second capacitor is connected between the inverting end of the second amplifier and the output end of the second amplifier.

7. The fingerprint device wake-up circuit according to claim 6, characterized in that: The second comparison unit outputs different fingerprint signals according to different signal inputs.

8. The fingerprint device wake-up circuit according to claim 1, characterized in that: The scanning frequency of the touch scanning circuit is lower than the scanning frequency of the fingerprint scanning circuit.

9. A fingerprint device, characterized in that: The fingerprint device comprises: a fingerprint device wake-up circuit as claimed in any one of claims 1 to 8.

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