KR102179874B1 - Fingerprint recongnition apparatus capable of detecting forged fingerprint and driving method thereof - Google Patents

Abstract

A plurality of sensor pads arranged in a matrix form and forming sensing capacitance in relation to a subject; A plurality of sensing circuits connected to each of the plurality of sensor pads and outputting different signals according to the size of the sensing capacitance; When a subject is not in contact with the plurality of sensor pads, it is directly connected to a grouped sensor pad comprising at least some sensor pads, and different signals are output according to the size of the composite value of the capacitance formed on the grouped sensor pads. A touch sensing unit; And a comparison unit configured to generate a control signal for activating the plurality of sensing circuits by comparing the output signal of the touch sensing unit with a comparison reference voltage.

Description

Fingerprint recognition device capable of detecting fake fingerprints and its driving method {FINGERPRINT RECONGNITION APPARATUS CAPABLE OF DETECTING FORGED FINGERPRINT AND DRIVING METHOD THEREOF}

The present invention relates to a fingerprint recognition device capable of detecting a counterfeit fingerprint and a driving method thereof.

Since fingerprint patterns differ from person to person, they are widely used in the field of personal identification. In particular, fingerprints are widely used in various fields such as finance, criminal investigation, and security as a means of personal authentication.

A fingerprint recognition device has been developed to recognize such fingerprints to identify individuals. A fingerprint recognition device is a device that touches a person's finger and recognizes a finger fingerprint, and is used as a means to determine whether or not a user is a legitimate user.

In recent years, the need for personal authentication and security reinforcement is rapidly increasing in the mobile market as well, and security related businesses through mobile are actively in progress.

As a method of implementing a fingerprint recognition device, various recognition methods such as an optical method, a thermal sensing method, and a capacitance method are known.

Among them, the capacitive fingerprint recognition device includes a plurality of sensor pads, the capacitance formed between each sensor pad and the ridge of the fingerprint, and the capacitance formed between the sensor pad and the valley of the fingerprint. A fingerprint image is formed by converting the difference into an electrical signal, comparing the size with a reference signal, and then digitizing and imaging the difference.

In general, a capacitive fingerprint recognition device includes a plurality of fingerprint sensing elements arranged in a matrix form. In order to continuously drive such a fingerprint sensing element to determine whether a finger is in contact and what part of the fingerprint is touching Electric power for its driving is bound to be continuously consumed.

To solve this problem, a technology has been developed to reduce power consumption by first putting the fingerprint recognition device in a standby state, and then determining whether a finger is in contact, and driving all fingerprint sensing elements when the finger is in contact.

As a method of determining whether a finger is in contact, a method of driving only some of a plurality of fingerprint sensing elements, a method of adding a separate electrode, etc. have been proposed. According to this method, the driving method of the fingerprint sensing element must be frequently changed, The design of the fingerprint sensor must be changed.

The present invention is to solve the problems of the prior art described above. After grouping the sensor pads of the fingerprint recognition device, the fingerprint recognition operation is activated when a finger touch is detected. Its purpose is to enable effective driving of a recognition device.

The objects of the present invention are not limited to the objects mentioned above, and other objects not mentioned will be clearly understood from the following description.

According to an embodiment of the present invention for achieving the above object, a plurality of sensor pads arranged in a matrix form and forming sensing capacitance in a relationship with a subject; A plurality of sensing circuits connected to each of the plurality of sensor pads and outputting different signals according to the size of the sensing capacitance; When a subject is not in contact with the plurality of sensor pads, it is directly connected to a grouped sensor pad comprising at least some sensor pads, and different signals are output according to the size of the composite value of the capacitance formed on the grouped sensor pads. A touch sensing unit; And a comparison unit configured to generate a control signal for activating the plurality of sensing circuits by comparing the output signal of the touch sensing unit with a comparison reference voltage.

Each of the plurality of sensing circuits may include an amplifier having a first input terminal selectively connected to the sensor pad through a first switch; It is connected between the first input terminal and the output terminal of the amplifier, and includes a feedback capacitance in which a potential difference between both ends is controlled by a second switch, and a third switch connected to the first switch, the second switch and the output terminal of the amplifier is All are controlled to be on, so that the sensor pad and the touch sensing unit can be directly connected.

The touch sensing unit may include an amplifier to which a first input terminal is selectively connected to the at least some sensor pads through a fourth switch; It is connected between the first input terminal and the output terminal of the amplifier, and may include a feedback capacitance in which a potential difference between both ends is controlled by a fifth switch.

The fingerprint recognition device may further include a Schmitt trigger circuit for stabilizing the output signal of the comparison unit.

The fingerprint recognition device may further include a forged fingerprint detection unit that is activated together with the plurality of sensing circuits to determine whether the recognized fingerprint is forged.

In addition, according to another embodiment of the present invention for achieving the above object, at least some of the plurality of sensor pads arranged in a matrix form and forming a sensing capacitance in a relationship with a subject are grouped to be interconnected; Allowing a touch sensing unit that outputs different signals to be directly connected to the grouped sensor pads according to the magnitude of a combined value of capacitance formed on the grouped sensor pads; And when the difference between the voltage level of the output terminal of the touch sensing unit and the comparison reference voltage exceeds a preset range, the connection between the grouped sensor pad and the touch sensing unit is cut off, and a sensing circuit connected to each of the plurality of sensor pads is A method of driving a fingerprint identification device is provided, comprising the step of enabling activation.

According to the present invention, after the sensor pads of the fingerprint recognition device are grouped, the fingerprint recognition operation is activated when a finger touch is detected therein, so that the fingerprint recognition device can be effectively driven without a separate electrode or a driving method change.

1 is a view showing an electronic device having a capacitive fingerprint recognition device according to an embodiment of the present invention.
2 is a block diagram schematically showing the configuration of a general fingerprint recognition device.
3 is a circuit diagram showing the configuration of a sensing circuit according to an embodiment of the present invention.
4 is a diagram illustrating a driving state of a fingerprint sensing device when a finger is not in contact according to an embodiment of the present invention.
5 is a diagram illustrating that all sensor pads are short-circuited and driven by one electrode according to an embodiment of the present invention.
6 is a diagram showing the configuration of a fingerprint recognition device according to an embodiment of the present invention.
7 is a timing diagram illustrating an operation of a touch sensing unit according to an embodiment of the present invention.
8 is a diagram illustrating a configuration of a fingerprint recognition device according to another embodiment of the present invention.

Hereinafter, the present invention will be described with reference to the accompanying drawings. However, the present invention may be implemented in various different forms, and therefore is not limited to the embodiments described herein. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and similar reference numerals are assigned to similar parts throughout the specification.

Throughout the specification, when a part is said to be "connected" to another part, this includes not only "directly connected" but also "indirectly connected" with another member interposed therebetween. . In addition, when a part "includes" a certain component, it means that other components may be further provided, rather than excluding other components unless specifically stated to the contrary.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating an electronic device having a capacitive fingerprint recognition device according to an exemplary embodiment.

Referring to FIG. 1, the electronic device 1 is a fingerprint recognition device 10 provided in at least a portion, and a display unit 20 that replaces an input unit with a touch screen method and displays a driving state of the electronic device 1 to a user. ) Can be included.

The fingerprint recognition device 10 is composed of a plurality of fingerprint sensing elements, and each fingerprint sensing element outputs different signals according to the size of the sensing capacitance formed by the relationship with the finger, and synthesizes these signals. An image can be acquired.

FIG. 2 is a block diagram schematically showing the configuration of the fingerprint recognition apparatus 10 of FIG. 1.

Referring to FIG. 2, the fingerprint recognition device 10 includes a plurality of fingerprint sensing elements 100 arranged in a matrix form, a sample and hold unit 200, a programmable gain amplifier (PGA) 300, and a differential signal generator (DSG). 400) and ADC (Analog to Digital Converter: 500).

Each fingerprint sensing element 100 includes a sensor pad 110 and a sensing circuit 120. The sensor pad 110 forms a sensing capacitance in relation to the finger, and the sensing circuit 120 generates an output signal according to the size of the sensing capacitance. A detailed configuration and operation of the sensing circuit 120 will be described later with reference to FIG. 3.

The sample and hold unit 200 samples a signal output from a specific sensing circuit 120 selected by a multiplexer (not shown), maintains it, and stores the value.

The PGA 300 performs a function of amplifying a signal output from the sample and hold unit 200 at a predetermined ratio. The degree of amplification may vary depending on the size of a signal currently output from the sample and hold unit 200.

The DSG 400 performs a function of converting a signal amplified by the PGA 300 into a differential signal, and the ADC 500 performs a function of digitizing an analog signal.

3 is a circuit diagram showing the configuration of the sensing circuit shown in FIG. 2.

Referring to FIG. 3, in the sensing circuit 120, a first input terminal N1 is selectively connected by a sensor pad 110 and a first switch S1, and a first reference voltage ( A first amplifier (A1) to which Vref) is input, a feedback capacitance (Cfb) connected between the first input terminal (N1) and the output terminal (N3) of the first amplifier (A1), and both ends of the feedback capacitance (Cfb). And a second switch S2 for controlling a potential, and a third switch S3 for selectively outputting a signal of the output terminal N3 of the first amplifier A1.

The first reference voltage Vref is described herein as being supplied to the second input terminal N2 of the first amplifier A1, but may be supplied through an external electrode (not shown). In this case, the first reference voltage Verf through the external electrode may be supplied to the human finger, and a response signal thereof may be provided to the sensor pad 110.

When sensing the fingerprint, the operation of the sensing circuit 120 will be described as follows.

First, when the first switch S1 and the third switch S3 are turned on, the sensing circuit 120 is in an operable state.

At this time, when the second switch S2 is turned on, the feedback capacitance Cfb of the first amplifier A1 is reset.

Next, the second switch S2 is switched to an off state and the first reference voltage Vref is switched from a high level to a low level or a low level to a high level. At this time, the output voltage Vout of the first amplifier A1 is formed according to the size of the sensing capacitance Cf formed between the sensor pad 110 and the finger.

The magnitude of the output voltage Vout of the first amplifier A1 may be expressed as follows.

Equation 1 represents the value of the output voltage Vout when the first reference voltage Vref is maintained at the high level VrefH and then switched to the low level VrefL when the second switch S2 is off. will be.

In such a fingerprint sensing operation, since the sensing circuits 120, which are present for each sensing pad 110, are all operated periodically, a lot of power is required. That is, regardless of whether a finger is in contact, all the sensing circuits 120 perform a fingerprint sensing operation for obtaining a fingerprint image, so that power consumption is inevitably increased.

Therefore, it is preferable in terms of power consumption efficiency to perform a fingerprint sensing operation for obtaining a fingerprint image when the finger is not in contact without performing a fingerprint sensing operation in the non-contact state.

That is, it is preferable that the fingerprint recognition apparatus is in a standby state and wakes up when it is confirmed whether a finger is in contact, and performs a fingerprint sensing operation.

4 is a diagram illustrating a driving state of a fingerprint sensing element when a finger is not in contact according to an exemplary embodiment.

Referring to FIG. 4, in an embodiment of the present invention, when the fingerprint recognition device is in a standby state, first to third switches S1 to S1 to 3 of the sensing circuit 120 included in at least some of the fingerprint sensing elements 100 All S3) remain on.

When all of the first to third switches S1 to S3 are kept in an on state, the sensor pad 110 is in a short state with the output terminal N3 of the first amplifier A1.

If the first to third switches S1 to S3 are all connected to the output terminals of the fingerprint sensing element 100, that is, the output terminals of the sensing circuit 120, the corresponding fingerprint sensing element 100 All of the sensor pads 110 included in it will be in a short-circuit state maintained in a coincident state.

5 is a diagram illustrating a connection relationship between sensor pads when first to third switches of all fingerprint sensing elements are maintained in an on state according to an embodiment of the present invention.

Referring to FIG. 5, if the first to third switches of all the fingerprint sensing elements are turned on and the multiplexer (not shown) is controlled to connect the output terminals of all the fingerprint sensing elements, all sensor pads 110 May be shorted to be equivalent to driving with one electrode.

5 illustrates a case in which the first to third switches of all fingerprint sensing elements are kept in an on state, but it is sufficient if the first to third switches included in at least some of the fingerprint sensing elements are driven in the ON state.

6 is a diagram showing the configuration of a fingerprint recognition device according to an embodiment of the present invention.

6, the fingerprint recognition device according to an embodiment of the present invention further includes a touch sensing unit 600, a comparison unit 700, and a Schmitt trigger circuit 800 to the fingerprint recognition device described with reference to FIG. 2 do.

In the touch sensing unit 600, the first input terminal N4 is selectively connected through the sensing circuit 120 and the fourth switch S4 of one or more fingerprint sensing elements 100, and the second input terminal N5 is 2 The second amplifier A2 to which the reference voltage Vref_t is supplied, the feedback capacitance Cfb_t connected between the first input terminal N4 and the output terminal N6 of the second amplifier A2, and the feedback capacitance ( Cfb_t) and a fifth switch (S5) for controlling the potentials of both ends, and a sixth switch (S6) for selectively outputting a signal of the output terminal (N6) of the second amplifier (A2).

However, according to another embodiment of the present invention, since the operation of the touch sensing unit 600 in the standby mode can be controlled only by the fourth switch S4, the sixth switch S6 for controlling the output signal is omitted (short circuit). ) May be.

Further, the second reference voltage Vref_t is described herein as being supplied to the second input terminal N5 of the second amplifier A2, but may be supplied through an external electrode (not shown). In this case, the second reference voltage Verf_t through the external electrode may be supplied to the human finger, and a response signal thereof may be provided to the sensor pad 110.

Hereinafter, an operation of the touch sensing unit 600 will be described with reference to FIGS. 6 and 7.

7 is a timing diagram illustrating operations of the fourth to sixth switches S4 to S6 of the touch sensing unit 600.

In Fig. 7, S4 to S6 represent control signals supplied to the fourth to sixth switches (S4 to S6), respectively, and when the control signal is switched from a low level to a high level, each switch is switched from an off state to an on state. do.

In addition, although FIG. 7 illustrates a case in which the second reference voltage Vref_t is switched from a high level to a low level, an embodiment in which the second reference voltage Vref_t is switched from a low level to a high level is also possible, and the following description applies as it is.

For reference, in the description related to the second reference voltage Vref_t, the low level and the high level do not mean the power levels ground and Vdd of the amplifier A2.

First, when the fingerprint recognition device is in a standby state, the fourth and sixth switches S4 and S6 are turned on to detect whether or not a finger is in contact (first section; T1).

As described with reference to FIG. 5, the sensor pads 110 of the fingerprint sensing element 100 in which all the switches of the sensing circuit 120 are kept in an on state are grouped by a multiplexer (not shown), so that a mutual short state is achieved. However, the grouped sensor pad 110 is connected to the second amplifier A2 of the touch sensing unit 600 as the fourth switch S4 is maintained in the ON state.

Next, in the second period T2, the fifth switch S5 is turned on and the feedback capacitance Cfb_t of the second amplifier A2 is reset. While the fifth switch S5 is maintained in the on state, both ends of the feedback capacitance Cfb_t have the same potential, and the voltage Vout_t of the output terminal N6 of the second amplifier A2 is a second reference voltage ( It becomes the same as the high level (VrefH_t) of Vref_t).

After that, the fifth switch S5 is turned off in the third section T3 to be in a state in which it is possible to check whether a finger is in contact.

In the fourth period T4, the second reference voltage Vref_t is switched from the high level VrefH_t to the low level VrefL_t. When a finger touches the grouped sensor pad 110, the second amplifier A2 The magnitude of the voltage Vout_t of the output terminal N6 changes. The voltage Vout_t of the output terminal N6 may be expressed as follows.

Here, the touch capacitance Cf_t (not shown) is a capacitance formed by a relationship between the grouped sensor pad 110 and a finger.

Since the size of the touch capacitance Cf_t increases as the finger approaches, the voltage Vout_t of the output terminal N6 of the second amplifier A2 decreases from VrefH_t according to the finger contact with the finger-grouped sensor pad 110. do.

Since the sensing capacitance Cf_t formed on the grouped sensor pads 110 is a value formed by combining the sensing capacitances Cf formed on each sensor pad 110, the size of the touch capacitance Cf_t May be a value considerably larger than the size of the sensing capacitance Cf formed in each sensor pad 110.

If the size of the feedback capacitance Cfb_t of the touch sensing unit 600 is the same as the size of the feedback capacitance Cfb of the sensing circuit 120, the second amplifier is also used for small noise or small touch capacitance Cf_t. The change in the voltage Vout_t of the output terminal N6 of A2) increases, so that the detection of a finger touch is not performed accurately.

Accordingly, the size of the feedback capacitance Cfb_t of the touch sensing unit 600 is preferably set to a value larger than the size of the feedback capacitance Cfb of the sensing circuit 120.

The voltage Vout_t of the output terminal N6 of the second amplifier A2 is input to the comparison unit 700, and the comparison unit 700 compares it with the comparison reference voltage Vcomp to generate an output signal.

To this end, the comparison unit 700 is a third amplifier to which the first input terminal N7 is connected to the output terminal N6 of the touch sensing unit 600 and the comparison reference voltage Vcomp is applied to the second input terminal N8. (A3) may be included.

That is, when the signal input to the first input terminal N7 of the third amplifier A3 becomes the voltage Vout_t of the output terminal N6, and the voltage Vout_t of the output terminal N6 is lower than the comparison reference voltage Vcomp , Output a high level signal.

When the high-level signal is output from the comparison unit 700, it means that a finger touch has occurred, and thus the fourth and sixth switches S4 and S6 in order to perform a sensing operation for obtaining a fingerprint image in the sensing circuit 120 Is switched to the off state (the fifth section; T5). It goes without saying that in the embodiment in which the sixth switch S6 is not provided, only the fourth switch S4 is switched to the off state.

That is, in the fifth period T5, the connection between the sensing circuit 120 and the touch sensing unit 600 is controlled to be turned off, and the first to third sensing circuits 120 of the fingerprint sensing element 100 are After switching all the switches S1 to S3 to the off state, a fingerprint recognition operation is performed according to the process described with reference to FIG. 3.

In addition, since the touch sensing unit 600 does not need to be driven in the fifth period T5, that is, when the fingerprint recognition operation is performed, the driving power for the touch sensing unit 600 and the second reference voltage Vref_t are Licensing may be suspended. Meanwhile, as illustrated in FIG. 7, the second reference voltage Vref_t may be converted back to the high level VrefH_t, and driving power may be applied to the touch sensing unit 600.

On the other hand, when the comparison unit 700 does not output a high level signal in the fourth section T4 (when a finger touch is not detected), the fourth switch and the sixth switch S4 are finished after the fourth section T4 is finished. , S6) is switched to the off state, and the first to fourth sections T1 to T4 are performed again. Alternatively, in this case, after the end of the fourth section (T4), the fourth and sixth switches (S4, S6) are continuously maintained, and the second section (T2) to the fourth section (T4) are performed again. You may.

The Schmitt trigger circuit 800 is a circuit for preventing the output signal of the comparator 700 from being affected by external noise. That is, it is provided to stabilize the output signal of the comparator, and the Schmitt trigger circuit 800 may be omitted.

As described above, in the present invention, since one or more sensor pads 110 are grouped, it is determined whether a finger is in contact therewith, and then whether or not a fingerprint recognition operation is started, a separate electrode does not need to be added to the fingerprint sensing element 100.

In addition, in the standby state of the fingerprint recognition device, power does not need to be applied to each of the first amplifiers A1 of the sensing circuits 120 included in each fingerprint sensing element 100, and the second Since power is applied only to the third amplifiers A2 and A3 of the amplifier and comparator 700, power efficiency in the standby state of the fingerprint recognition device can be greatly improved.

The functions of the sample and hold unit 200, the PGA 300, the DSG 400, and the ADC 500 in FIG. 6 are the same as those described with reference to FIG. 2, and the description thereof will be omitted here.

8 is a diagram illustrating a configuration of a fingerprint recognition device according to another embodiment of the present invention.

Referring to FIG. 8, the fingerprint recognition apparatus of the present invention may additionally include a forged fingerprint detection unit 900 to the fingerprint recognition apparatus described with reference to FIG. 6.

As described above, when a finger touch occurs on the grouped sensor pad 110, a high-level signal is output from the Schmitt trigger circuit 800, and according to the output of this signal, the fingerprint sensing element 100 recognizes the fingerprint. At the same time as the operation is performed, the forged fingerprint detection unit 900 may be activated.

The counterfeit fingerprint detection unit 900 determines whether the recognized fingerprint is a counterfeit fingerprint by comparing the fingerprint image or feature point acquired by the control unit 1000 through the fingerprint recognition operation with a previously registered fingerprint image or feature point. Can be identified.

In addition, a counterfeit fingerprint may be detected through the electrical characteristics of the subject in contact, and a counterfeit fingerprint detection operation may be performed through various methods.

The forged fingerprint detection unit 900 activates the fingerprint recognition operation of the fingerprint recognition device only when a finger touch is detected by the touch sensing unit 600, that is, the output signal of the comparator 700 outputs a high level signal. Since it is driven only when it is turned on, standby power can be reduced.

In the above, the present invention has been described by specific matters such as specific elements and limited embodiments and drawings, but this is provided only to help a more general understanding of the present invention, and the present invention is not limited to the above embodiments. , Anyone with ordinary knowledge in the technical field to which the present invention pertains can make various modifications and variations from these descriptions.

Therefore, the spirit of the present invention is limited to the above-described embodiments and should not be defined, and all modifications equivalently or equivalently to the claims as well as the claims to be described later fall within the scope of the spirit of the present invention. I would say.

1: electronic devices
10: fingerprint reader
20: display
100: fingerprint sensing element
110: sensor pad
120: sensing circuit
200: sample and hold unit
300: PGA
400: DSG
500: ADC
600: touch sensing unit
700: comparison unit
800: Schmitt trigger circuit
900: counterfeit fingerprint detection unit
1000: control unit

Claims (6)

A plurality of sensor pads arranged in a matrix form and forming sensing capacitance in relation to a subject;
A plurality of sensing circuits connected to each of the plurality of sensor pads and outputting different signals according to the size of the sensing capacitance;
When a subject is not in contact with the plurality of sensor pads, it is directly connected to a grouped sensor pad comprising at least some sensor pads, and different signals are output according to the size of the composite value of the capacitance formed on the grouped sensor pads. A touch sensing unit; And
Comprising a comparison unit for generating a control signal for activating the plurality of sensing circuits by comparing the output signal of the touch sensing unit with a comparison reference voltage,
Each of the plurality of sensing circuits,
An amplifier to which a first input terminal N1 is selectively connected to the sensor pad through a first switch; And
A first feedback capacitance connected between the first input terminal N1 and the output terminal of the amplifier and controlling a potential difference between both ends by a second switch,
The first switch, the second switch, and the third switch connected to the output terminal of the amplifier are all controlled to be on, so that the sensor pad and the touch sensing unit are directly connected,
The first switch, the second switch, and the third switch are all turned on to equalize the plurality of sensor pads to one electrode,
When a touch is detected on the plurality of equivalent sensor pads, a fingerprint sensing operation is activated,
The touch sensing unit,
An amplifier in which the first input terminal N4 is selectively connected through the at least some sensor pads and a fourth switch, and
A second feedback capacitance connected between the first input terminal (N4) and the output terminal of the amplifier selectively connected through the fourth switch, and controlling a potential difference between both ends by a fifth switch,
The size of the second feedback capacitance is greater than the size of the first feedback capacitance,
In a standby state, the fingerprint recognition apparatus controls so that power is not supplied to an amplifier included in each of the plurality of sensing circuits.
delete delete The method of claim 1,
Further comprising a Schmitt trigger circuit for stabilizing the output signal of the comparison unit, fingerprint recognition device.
The method of claim 1,
A fingerprint recognition apparatus further comprising a forged fingerprint detection unit that is activated together with the plurality of sensing circuits to determine whether the recognized fingerprint is forged.
Grouping at least some of the plurality of sensor pads arranged in a matrix form and forming a sensing capacitance in a relationship with a subject to be interconnected;
Allowing a touch sensing unit that outputs different signals to be directly connected to the grouped sensor pads according to the magnitude of a combined value of capacitance formed on the grouped sensor pads; And
When the difference between the voltage level of the output terminal of the touch sensing unit and the comparison reference voltage exceeds a preset range, the connection between the grouped sensor pad and the touch sensing unit is cut off, and a sensing circuit connected to the plurality of sensor pads is activated. Includes the step of making,
Each of the plurality of sensing circuits,
An amplifier to which a first input terminal N1 is selectively connected to the sensor pad through a first switch; And
A first feedback capacitance connected between the first input terminal N1 and the output terminal of the amplifier and controlling a potential difference between both ends by a second switch,
The first switch, the second switch, and the third switch connected to the output terminal of the amplifier are all controlled to be on, so that the sensor pad and the touch sensing unit are directly connected,
The first switch, the second switch, and the third switch are all turned on to equalize the plurality of sensor pads to one electrode,
When a touch is detected on the plurality of equivalent sensor pads, a fingerprint sensing operation is activated,
The touch sensing unit,
An amplifier in which the first input terminal N4 is selectively connected through the at least some sensor pads and a fourth switch, and
A second feedback capacitance connected between the first input terminal N4 and the output terminal of the amplifier selectively connected through the fourth switch and controlling a potential difference between both ends by a fifth switch,
The size of the second feedback capacitance is larger than the size of the first feedback capacitance,
A method of driving a fingerprint recognition apparatus, controlling power to not be supplied to an amplifier included in each of the plurality of sensing circuits in a standby state.

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