CN205540784U - Capacitanc fingerprint detection circuit, sensor and equipment - Google Patents
Capacitanc fingerprint detection circuit, sensor and equipment Download PDFInfo
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- CN205540784U CN205540784U CN201620075519.0U CN201620075519U CN205540784U CN 205540784 U CN205540784 U CN 205540784U CN 201620075519 U CN201620075519 U CN 201620075519U CN 205540784 U CN205540784 U CN 205540784U
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Abstract
The utility model provides a capacitanc fingerprint detection circuit, sensor and equipment. Wherein, this detection circuitry includes: precharge potential source, voltage buffer, detecting element, integrator and detection circuitry board, above -mentioned detecting element is connected with precharge potential source, voltage buffer and integrator respectively, receives the voltage of precharge potential source and voltage buffer transmission to the integrator is given to transmission fingerprint electric charge, the fingerprint electric charge of detecting element transmission is received to the integrator, produces the fingerprint signal according to this fingerprint electric charge total mark to output fingerprint signal, precharge potential source, voltage buffer, detecting element and integrator are all installed on the detection circuitry board. The utility model discloses, on need not being connected to drive signal user's finger through outer electrode for above -mentioned detection circuitry integrates technology and becomes simply when combining with other equipment, and increased capacitanc fingerprint detection circuitry's applied scene.
Description
Technical field
The utility model relates to IC design and fingerprinting detection technique field, specifically,
Relate to a kind of capacitance type fingerprint testing circuit, sensor and equipment.
Background technology
People are more and more higher to the requirement of information security, in gate inhibition, work attendance and movement now
The fields such as equipment are required for being determined the identity of user by identification, and fingerprint recognition is
Current application most widely a kind of identification mode.
At present, it is mostly to use capacitance type fingerprint detection device to carry out fingerprint detection, electric capacity
Formula finger print detection device includes detection chip and outer electrode, and outer electrode is by pumping signal
It is connected on the finger of user, then forms fingerprint detection loop with the circuit in detection chip,
Thus realize user is carried out fingerprint detection.
But prior art needs pumping signal to be connected to by outer electrode the finger of user
On, outer electrode is in the outside of detection chip so that capacitance type fingerprint detection device with its
When his equipment is used in combination, integrated process technical sophistication, greatly limit capacitance type detector
Application scenarios.
Utility model content
In view of this, the utility model provides a kind of capacitance type fingerprint testing circuit, sensing
Device and equipment, being used for solving existing capacitance type fingerprint detection device needs to pass through outer electrode
Pumping signal is connected on the finger of user so that capacitance type fingerprint detection device with its
When his equipment is used in combination, integrated process technical sophistication, greatly limit capacitance type detector
The problem of application scenarios.
First aspect, the utility model embodiment provides a kind of capacitance type fingerprint testing circuit,
Including: precharge potential source, voltage buffer, detecting element, integrator and testing circuit
Plate；
Described detecting element respectively with described precharge potential source, described voltage buffer and institute
State integrator to connect, receive described precharge potential source and the voltage of described voltage buffer transmission,
And transmission fingerprint electric charge is to described integrator；
Described integrator receives the Charge fingerprint of described detecting element transmission, according to described fingerprint
Charge integration produces fingerprint signal, and exports described fingerprint signal；
Described precharge potential source, described voltage buffer, described detecting element and described integration
Device is installed on described testing circuit plate.
In conjunction with first aspect, the utility model embodiment provides the first of above-mentioned first aspect
Planting possible implementation, wherein, described detecting element includes: detecting electrode and isolation electricity
Pole；
Described isolation electrode is connected and institute by the first switch with described precharge potential source respectively
State voltage buffer to be connected by second switch, receive the first of the transmission of described precharge potential source
Voltage and receive described voltage buffer transmission the second voltage；
Described detecting electrode is connected with described by the 3rd switch with described isolation electrode respectively
Integrator is connected by the 4th switch.
In conjunction with the first possible implementation of first aspect, the utility model embodiment carries
The implementation that the second of above-mentioned first aspect is possible, wherein, described integrator bag are supplied
Include operational amplifier, integrating condenser and the 5th switch；
The inverting input of described operational amplifier respectively with one end of described integrating condenser,
One end of described 5th switch connects, and by described 4th switch and described detecting electrode
Connect；
The output of described operational amplifier respectively with the other end and the institute of described integrating condenser
The other end stating the 5th switch connects；
The in-phase input end of described operational amplifier is connected with reference voltage source, receives described base
The reference voltage of reference voltage source transmission.
In conjunction with the implementation that the second of first aspect is possible, the utility model embodiment carries
The third possible implementation of above-mentioned first aspect, wherein, described testing circuit are supplied
Also include A/D converter；
Described A/D converter is connected with the output of described operational amplifier, receives described fortune
Calculate the fingerprint signal of the output output of amplifier, and described fingerprint signal is converted into fingerprint
Data signal.
In conjunction with the first possible implementation of first aspect, the utility model embodiment carries
The 4th kind of possible implementation of above-mentioned first aspect, wherein, described detecting electrode are supplied
The metal electrode constituted for the top-level metallic in described testing circuit plate.
In conjunction with the first possible implementation of first aspect, the utility model embodiment carries
The 5th kind of possible implementation of above-mentioned first aspect, wherein, described isolation electrode are supplied
The metal electrode constituted for top-level metallic secondary in described testing circuit plate, and described isolation electricity
The most U-shaped, described detecting electrode is wrapped up.
In conjunction with first aspect, the utility model embodiment provides the 6th of above-mentioned first aspect
Planting possible implementation, wherein, described precharge potential source includes external voltage source or described
The low noise voltage source that testing circuit intralamellar part produces.
Second aspect, the utility model embodiment provides a kind of capacitance type fingerprint detection sensing
Device, including: the condenser type described in multiple pixel sensing elements and multiple above-mentioned first aspect refers to
Line testing circuit, pixel sensing element and capacitance type fingerprint testing circuit one_to_one corresponding；
The capacitance type fingerprint testing circuit connection that pixel sensing element is the most corresponding, transmission
Fingerprint induced signal gives the capacitance type fingerprint testing circuit of its correspondence.
In conjunction with second aspect, the utility model embodiment provides the first of above-mentioned second aspect
Kind possible implementation, wherein, described pixel sensing element include multiple fingerprint inductor,
Multiple CMOS cmos switches and emulation bus, fingerprint inductor and CMOS
Switch one_to_one corresponding；
Fingerprint inductor is connected to described emulation bus by corresponding cmos switch
On；
The capacitance type fingerprint testing circuit that described emulation bus is corresponding with described pixel sensing element
Connect.
The third aspect, the utility model embodiment provides a kind of capacitance type fingerprint detection equipment,
Including detection panel, processor, shell and the capacitance type fingerprint described in above-mentioned second aspect
Detection sensor；
Described capacitance type fingerprint detection sensor is embedded on described detection panel, described detection faces
Plate and described processor are respectively mounted on the housing；
Described capacitance type fingerprint detection sensor is connected with described processor, transmission fingerprint numeral
Signal gives described processor.
Capacitance type fingerprint testing circuit, sensor and the equipment that the utility model provides, is not required to
Pumping signal is connected on the finger of user by outer electrode to be passed through so that above-mentioned condenser type
Fingerprint detection circuit becomes simple in integrated process when other equipment are combined, and adds
The application scenarios of capacitance type fingerprint testing circuit.
For making above-mentioned purpose of the present utility model, feature and advantage can become apparent, hereafter
Especially exemplified by preferred embodiment, and coordinate appended accompanying drawing, be described in detail below.
Accompanying drawing explanation
In order to be illustrated more clearly that the technical scheme of the utility model embodiment, below will be to reality
Execute the required accompanying drawing used in example to be briefly described, it will be appreciated that the following drawings is only shown
Go out some embodiment of the present utility model, be therefore not construed as the restriction to scope,
For those of ordinary skill in the art, on the premise of not paying creative work, also
Other relevant accompanying drawings can be obtained according to these accompanying drawings.
Fig. 1 shows a kind of capacitance type fingerprint detection electricity that the utility model embodiment 1 provides
The structural representation on road；
Fig. 2 shows a kind of capacitance type fingerprint detection electricity that the utility model embodiment 1 provides
The structural representation of the detecting element in road；
Fig. 3 shows that a kind of capacitance type fingerprint detection that the utility model embodiment 1 provides passes
The structural representation of the integrator in sensor；
Fig. 4 shows a kind of capacitance type fingerprint detection electricity that the utility model embodiment 1 provides
The circuit diagram on road；
Fig. 5 shows that a kind of capacitance type fingerprint detection that the utility model embodiment 2 provides passes
The structural representation of sensor；
Fig. 6 shows that a kind of capacitance type fingerprint detection that the utility model embodiment 3 provides sets
Standby structural representation.
Fig. 4 description of reference numerals is as follows:
Detecting electrode 131, isolation electrode 132, the first switch 401, second switch 402,
3rd switch the 403, the 4th switchs the 404, the 5th switch 143, operational amplifier 141, amasss
Divide capacitor 142, reference voltage source 406, voltage buffer 120 and precharge potential source
110。
Detailed description of the invention
Below in conjunction with accompanying drawing in the utility model embodiment, in the utility model embodiment
Technical scheme be clearly and completely described, it is clear that described embodiment be only
A part of embodiment of the present utility model rather than whole embodiments.Generally the most attached
Described in figure, the assembly with the utility model embodiment illustrated can be with various different configurations
Arrange and design.Therefore, below to the embodiment of the present utility model provided in the accompanying drawings
Detailed description be not intended to limit claimed scope of the present utility model, but only
Represent selected embodiment of the present utility model.Based on embodiment of the present utility model, this area
The every other enforcement that technical staff is obtained on the premise of not making creative work
Example, broadly falls into the scope of the utility model protection.
To need to be swashed by outer electrode in view of capacitance type fingerprint of the prior art detection device
Encouraging on the finger being signally attached to user, outer electrode, in the outside of detection chip, so makes
Obtain capacitance type fingerprint detection device integrated process technology when being used in combination with other equipment multiple
Miscellaneous, greatly limit the application scenarios of capacitance type detector.Based on this, the utility model
Embodiment provides a kind of capacitance type fingerprint testing circuit, sensor and equipment.Below by
Embodiment is described.
Embodiment 1
The utility model embodiment provides a kind of capacitance type fingerprint testing circuit.This fingerprint is examined
Slowdown monitoring circuit need not be connected to pumping signal by outer electrode the finger of user, and fingerprint is believed
Number collection all complete inside this testing circuit.
As it is shown in figure 1, the capacitance type fingerprint testing circuit that the utility model embodiment provides,
Including: precharge potential source 110, voltage buffer 120, detecting element 130, integrator 140
And testing circuit plate 150；
Detecting element 130 respectively with precharge potential source 110, voltage buffer 120 and long-pending
Divide device 140 to connect, receive precharge potential source 110 and the voltage of voltage buffer 120 transmission,
And transmission fingerprint electric charge is to integrator 140；
Integrator 140 receives the Charge fingerprint of detecting element 130 transmission, according to this fingerprint electricity
Lotus integration produces fingerprint signal, and exports this fingerprint signal；
Precharge potential source 110, voltage buffer 120, detecting element 130 and integrator
40 are installed on testing circuit plate 150.
Wherein, above-mentioned precharge potential source 110 can be external voltage source, it is also possible to for detection
The internal low noise voltage source produced of circuit board 150, and low noise voltage source is a kind of noise
The voltage source that coefficient is the lowest, if above-mentioned precharge potential source 110 is external voltage source, then goes up
Stating precharge potential source 110 can be the battery on this capacitance type fingerprint testing circuit place equipment
Or battery pack.
The slow device 120 of voltage punching is a voltage source, can outwards transmit voltage, in this practicality
In new embodiment, voltage buffer 120 transmits voltage to detecting element 130.
Above-mentioned testing circuit plate 150 can be that (Printed Circuit Board prints PCB
Circuit board) plate.
In the utility model embodiment, the finger of people contacts with detecting element 130, can produce
A raw fingerprint capacitor, precharge potential source 110 is connected with detecting element 130, transmits voltage
To detecting element 130, precharge potential source 110 is transferred to the voltage note of detecting element 130
Being the first voltage, voltage buffer 120 is also connected with detecting element 130, and transmits electricity
Voltage buffer 120, to detecting element 130, is transferred to the voltage of detecting element 130 by pressure
Being designated as the second voltage, wherein, above-mentioned first voltage can be more than the second voltage, detecting element
30 the first voltages receiving precharge potential source 110 transmission respectively, and receive voltage buffer
Device 120 transmission the second voltage, detecting element 130 by the first voltage received, second
Voltage and fingerprint capacitor, generate Charge fingerprint, and this Charge fingerprint be transferred to integrator
140, after integrator 140 receives the Charge fingerprint of detecting element 130 transmission, this is referred to
Line electric charge is integrated computing, produces a fingerprint signal, and this fingerprint signal is a fingerprint
Analog signal, and export this fingerprint signal.
Wherein, above-mentioned precharge potential source 110, voltage buffer 120, detecting element 130
And integrator 140 is installed on testing circuit plate 150, above-mentioned precharge potential source 110,
Voltage buffer 120, detecting element 130 and integrator 140 are all integrated in testing circuit
On plate 150, forming a complete fingerprint detection circuit, this fingerprint detection circuit can be complete
Become the collection of fingerprint capacitor, the transmission of voltage and the generation of fingerprint signal, it is not necessary to external
Pumping signal is connected on the finger of user by electrode.
Wherein, as an embodiment, as in figure 2 it is shown, above-mentioned detecting element 130 includes:
Detecting electrode 131 and isolation electrode 132.
Isolation electrode 132 is connected and electricity by the first switch with precharge potential source 110 respectively
Compression buffer 120 is connected by second switch, receives the transmission of above-mentioned precharge potential source 110
First voltage and the second voltage of reception voltage buffer 120 transmission；
Detecting electrode 131 is connected and integration by the 3rd switch with isolation electrode 132 respectively
Device 140 is connected by the 4th switch.
In the utility model embodiment, isolation electrode 132 passes through with precharge potential source 110
First switch connects, when above-mentioned first switches off, and isolation electrode 132 and pre-charge pressure
Being off between source 110, isolation electrode 132 cannot receive precharge potential source 110 and pass
The first defeated voltage, when after above-mentioned first switch Guan Bi, isolates electrode 132 and pre-charge pressure
Setting up between source 110 and connect, at this moment, isolation electrode 132 can receive precharge potential source 110
First voltage of transmission, isolation electrode 132 also passes through second switch with voltage buffer 120
Connect, when second switch disconnects, between isolation electrode 132 and voltage buffer 120 be
Disconnecting, at this moment isolation electrode 132 cannot receive the second of voltage buffer 120 transmission
Voltage, after above-mentioned second switch closes, isolation electrode 132 and voltage buffer 120 it
Between set up and connect, at this moment isolation electrode 132 can receive the of voltage buffer 120 transmission
Two voltages.
Connected by the 3rd switch between above-mentioned detecting electrode 131 and isolation electrode 132, when
Above-mentioned 3rd when switching off, and is off between detecting electrode 131 and isolation electrode 132,
First voltage of precharge potential source 110 transmission that at this moment isolation electrode 132 receives, Yi Jijie
Second voltage of voltage buffer 120 transmission received cannot be transferred to detecting electrode 131,
When, after above-mentioned 3rd switch Guan Bi, between detecting electrode 131 and isolation electrode 132, foundation is even
Connecing, at this moment the voltage received can be transferred to detecting electrode 131 by isolation electrode 132,
This voltage is the first voltage or the second voltage.Above-mentioned detecting electrode 131 also with integrator 140
Connected by the 4th switch, when the above-mentioned 4th switches off, above-mentioned detecting electrode 131 He
Being off between integrator 140, integrator 140 is to receive detecting electrode 131
The Charge fingerprint of transmission, after above-mentioned 4th switch closes, detecting electrode 131 and integration
Setting up between device 140 and connect, at this moment the Charge fingerprint produced can be passed by detecting electrode 131
It is defeated by integrator 140.
In the above-described embodiments, the finger of people contacts with detecting electrode 131, the finger of people and
Measured capacitance, namely a fingerprint capacitor, this fingerprint can be produced between detecting electrode 131
Voltage on electric capacity and detecting electrode 131 forms Charge fingerprint, and is transmitted by this Charge fingerprint
To integrator 140.
Wherein, as an embodiment, above-mentioned detecting electrode 131 is above-mentioned testing circuit plate
The metal electrode that top-level metallic in 150 is constituted；Above-mentioned isolation electrode 132 is above-mentioned detection
The metal electrode that in circuit board 150, time top-level metallic is constituted, and isolate electrode 132 in U
Font, wraps up described detecting electrode 131.
In the utility model embodiment, detecting electrode 131 and isolation electrode 132 are all inspections
Metal on slowdown monitoring circuit plate 150 is constituted, and wherein, detecting electrode 131 is testing circuit plate
The metal electrode that top-level metallic on 150 is constituted, and isolating electrode 132 is testing circuit plate
Secondary top layer on 150, the metal electrode that namely second layer metal is constituted, and, isolation
Electrode 132 is U-shaped, and detecting electrode 131 is yi word pattern, and detecting electrode 131 is in isolation
The top of the U-shaped of electrode 132, so, detecting electrode 131 is wrapped by isolation electrode 132
Wrap so that detecting electrode 131 is isolated from the outside.
Wherein, as an embodiment, as it is shown on figure 3, integrator 140 includes:
Operational amplifier 141, integrating condenser 142 and the 5th switch 143.
The inverting input of operational amplifier 141 respectively with one end of integrating condenser 142,
One end of 5th switch 143 connects, and is connected with detecting electrode 131 by the 4th switch；
The output of operational amplifier 141 respectively with the other end and of integrating condenser 142
The other end of five switches 143 connects；
The in-phase input end of operational amplifier 141 is connected with reference voltage source, receives benchmark electricity
The reference voltage of potential source transmission.
Wherein, above-mentioned operational amplifier 141 includes two inputs, an output, two
Individual input is respectively in-phase input end and inverting input.
In the utility model embodiment, the inverting input of operational amplifier 141 is by the
Four switches and detecting electrode 131 connect, when the 4th switches off, and operational amplifier 141
And do not connect between detecting electrode 131, at this moment operational amplifier 141 is to connect
Receive the Charge fingerprint of detecting electrode 131 transmission, when after above-mentioned 4th switch Guan Bi, transport
Calculate to set up between amplifier 141 and detecting electrode 131 and connect, at this moment, detecting electrode 131
The Charge fingerprint of generation can be transferred to operational amplifier 141.Operational amplifier 141
Inverting input also connects with one end of integrating condenser 142 and one end of the 5th switch 143
Connect, and the output of operational amplifier 141 respectively with the other end of integrating condenser 142 with
And the 5th switch 143 the other end connect, when operational amplifier 141 receives detecting electrode
After the Charge fingerprint of 131 transmission, this Charge fingerprint can be integrated, generate fingerprint signal,
And by the output of operational amplifier 141, this fingerprint signal is exported.
The in-phase input end of operational amplifier 141 and reference voltage source connect, and receive benchmark electricity
The reference voltage of potential source transmission.
Wherein, when the above-mentioned 5th switchs 143 disconnection, integrating condenser 142 can carry out electricity
The accumulation of lotus, after switching 143 Guan Bis when the above-mentioned 5th, the electric charge on integrating condenser 142
Will reset, and, the inverting input of operational amplifier 141 and the voltage of output
Also said reference voltage can be initialized as.
In order to the fingerprint signal that above-mentioned integrator 140 exports to be converted into fingerprint numeral letter
Number, above-mentioned capacitance type fingerprint testing circuit also includes A/D converter；
A/D converter is connected with the output of operational amplifier 141, receives operational amplifier
The fingerprint signal of the output output of 141, and this fingerprint signal is converted into fingerprint numeral letter
Number.
In the utility model embodiment, the inverting input of operational amplifier 141 and detection
Electrode 131 connects, and receives the Charge fingerprint of detecting electrode 131 transmission, and to this fingerprint electricity
Lotus is integrated, and generates fingerprint signal, and this fingerprint signal is fingerprint analog signal, and computing is put
Output and the A/D converter of big device 141 connect, and the fingerprint signal of generation is transferred to mould
/ number converter, when A/D converter receives the fingerprint signal of operational amplifier 141 transmission
After, this fingerprint signal is converted into fingerprint data signal, and this fingerprint data signal is exported.
In order to introduce the capacitance type fingerprint detection electricity that the utility model embodiment provides in more detail
Annexation between each components and parts in road, carries below in conjunction with the utility model embodiment
For capacitance type fingerprint testing circuit circuit diagram to this testing circuit and this detection electricity
Road carries out the method for fingerprint detection and is introduced, the condenser type that the utility model embodiment provides
The circuit diagram of fingerprint detection circuit is as shown in Figure 4.
In the utility model embodiment, isolation electrode 132 switchs 401 with pre-by first
Charging potential source 110 connects, and is connected by second switch 402 and voltage buffer 120, inspection
Survey electrode 131 and isolation electrode 132 by the 3rd switch 403 connection, finger and detection electricity
Pole 131 contacts, and produces detection electric capacity, i.e. fingerprint capacitor, operational amplifier 141 anti-phase
Input is connected by the 4th switch 404 and detecting electrode 131, operational amplifier 141
Inverting input the most respectively with one end of integrating condenser 142 and the one of the 5th switch 143
End connects, the output of operational amplifier 141 respectively with the other end of integrating condenser 142
And the 5th switch 143 the other end connect, the in-phase input end of operational amplifier 141 and
Reference voltage source 406 connects, and receives the reference voltage of reference voltage source 406 transmission.
Use above-mentioned capacitance type fingerprint testing circuit to carry out fingerprint detection to comprise the steps:
Close the 5th switch 143, the electric charge of accumulation on integrating condenser 142 is reset, with
Time connect due to in-phase input end and the reference voltage source 406 of operational amplifier 141, receive
The reference voltage V of reference voltage source 406 transmission3, now, operational amplifier 141 anti-phase
The voltage of output and output is also initialized as reference voltage V3, here it is fingerprint detection
In reseting stage, after reseting stage completes, then entering signal acquisition phase.
Wherein, signal acquisition stage includes following three step:
Preliminary filling, signal compensation and signal integration.
Close the 3rd switch 403 and first switch 401, such detecting electrode 131 and every
Set up between ionization electrode 132 and connect, build between isolation electrode 132 and precharge potential source 110
Vertical connection, i.e. isolation electrode 132 receive the first voltage V of precharge potential source 110 transmission1,
And by this first voltage V1Be transferred to detecting electrode 131, at this moment, detecting electrode 131 and
Voltage on isolation electrode 132 is all charged to the first voltage V in advance1。
Describing for convenience, it is assumed that human body grounding, the voltage of such human body is 0, due to inspection
The voltage surveyed on electrode 131 is V1, between finger and the detecting electrode 131 of people, there is voltage
Difference, therefore, when the finger of people contacts with above-mentioned detecting electrode 131, can produce tested electricity
Hold Cf, i.e. fingerprint capacitor Cf, and now detecting electrode 131 and the electricity on isolation electrode 132
Press equal, parasitic capacitance C therefore formed between detecting electrode 131 and isolation electrode 132bot
Being zero, at this moment, on detecting electrode 131, the total amount of electric charge of storage is: Q0=V1·Cf, should
Storage electric charge is exactly Charge fingerprint, here it is preliminary filling process.
After preliminary filling completes, then Guan Bi second switch 402, at this moment, isolate electrode 132 He
Setting up between voltage buffer 120 and connect, isolation electrode 132 receives voltage buffer 120
Second voltage V of transmission2, now, the voltage on isolation electrode 132 is from V1Drop to V2,
Wherein, the first voltage V1More than the second voltage V2, and, originally it was stored in detecting electrode
Charge fingerprint Q on 1310Detecting electrode 131 and isolation electrode 132 redistribute,
But the total amount of Charge fingerprint keeps constant, and this process is then signal compensation process, at signal
After compensation terminates, the voltage on isolation electrode 132 is the second voltage V2。
After signal compensation process completes, then Guan Bi the 4th switch 404, at this moment, detection electricity
Set up between the inverting input of pole 131 and operational amplifier 141 and connect, detecting electrode 131
On Charge fingerprint can be transferred to operational amplifier 141, by operational amplifier 141 will receive
To Charge fingerprint transfer on integrating condenser 142, and, in this stage, detection electricity
Pole 131 also receives the reference voltage V of operational amplifier 141 inverting input transmission3, therefore,
Voltage V on the basis of voltage on detecting electrode 1313, and isolate the voltage on electrode 132 and be
V2, at this moment, between detecting electrode 131 and isolation electrode 132, there is voltage difference, therefore,
Parasitic capacitance C between detecting electrode 131 and isolation electrode 132botIt is not zero, at this moment,
On detecting electrode 131, the net charge of storage is: Q1=V3·Cf+(V3-V2)·Cbot, wherein,
CbotFor detecting electrode 131 and isolation electrode 132 between produce parasitic capacitance, therefore,
By the charge Q of accumulation on detecting electrode during preliminary filling 1310And this process detecting electrode
The charge Q of storage on 1311The quantity of electric charge transferred on integrating condenser 142 can be calculated
Δ Q=Q0-Q1, i.e. Δ Q=(V1-V3)·Cf-(V3-V2)·Cbot, wherein, Δ Q is for transferring to
The quantity of electric charge on integrating condenser 142, this process is then signal integration process, now, then
Complete the most complete signals collecting.
Wherein, in the computing formula of above-mentioned Δ Q, reference voltage V3And voltage buffer
120 the second voltage V produced2Unequal, can be reference voltage V3More than the second voltage
V2, it is also possible to it is reference voltage V3Less than the second voltage V2, such reference voltage V3With second
Voltage V2Between have a voltage difference, therefore tested charge signal can be produced one
(V3-V2)·CbotCharge signal compensate, this charge signal compensate can be positive charge signal
Compensate, it is also possible to be negative electrical charge signal compensation, so can be to the fingerprint valley of fingerprint and fingerprint
The basal signal existed between ridge compensates, and only selects between fingerprint valley and fingerprint ridge
Difference signal is integrated sampling, it is hereby achieved that a widest fingerprint valley/ridge signal is adopted
Sample dynamic range.
In order to a small-signal being converted into a big signal being prone to measure, N can be repeated
Secondary last time signal acquisition process, wherein, N is a positive integer more than zero, if repeated
The above-mentioned signal acquisition process of n times, then transfer to the total quantity of electric charge on integrating condenser 142
For N Δ Q, this total quantity of electric charge is exactly the semaphore that operational amplifier 141 obtains, this signal
Measure after operational amplifier 141 is integrated processing, in the output of operational amplifier 141
End obtains a N (Δ Q/Cint) voltage swing, wherein, CintIt it is integrating condenser 142
Produce integrating capacitor, from above-mentioned formula it can be seen that by regulation repeating signal collection
The size of times N value and integrating capacitor C that produces of integrating condenser 142intSize,
One small-signal can be converted into a big signal being prone to measure, the most both can reduce
Required precision to A/D converter, it is also possible to improve the signal to noise ratio of the fingerprint signal obtained.
After signal acquisition stage completes, then enter measuring phases, operational amplifier 141
Output by integration produce a N (Δ Q/Cint) voltage swing, namely fingerprint letter
Number, but this fingerprint signal is fingerprint analog signal, therefore, and operational amplifier 141 defeated
Go out end and this fingerprint signal is transferred to A/D converter, put when A/D converter receives computing
After the fingerprint signal of the output transmission of big device 141, then this fingerprint signal is converted into fingerprint
Data signal, and export this fingerprint data signal.
Above-described embodiment, is the capacitance type fingerprint detection electricity providing the utility model embodiment
Circuit diagram and the using method on road are illustrated, it is also possible to often complete a signal
After gathering and measuring, will reset by foregoing circuit, when such next time carries out fingerprint detection,
Directly from the beginning of signal acquisition stage, certain the utility model does not limit above-mentioned condenser type and refers to
The specifically used method step of line testing circuit.
The first switch 401 in this use new embodiment, second switch the 402, the 3rd are opened
Close the 403, the 4th switch 404 and the 5th switch 143 can be electromagnetic relay.
The capacitance type fingerprint testing circuit that the utility model provides, it is not necessary to pass through outer electrode
Pumping signal is connected on the finger of user so that above-mentioned capacitance type fingerprint testing circuit exists
Integrated process becomes simple when other equipment are combined, and adds capacitance type fingerprint detection
The application scenarios of circuit.
Embodiment 2
The utility model embodiment provides a kind of capacitance type fingerprint detection sensor.
As it is shown in figure 5, the capacitance type fingerprint detection sensor that the utility model embodiment provides
Including:
The capacitance type fingerprint inspection that multiple pixel sensing elements 510 and above-described embodiment 1 provide
Slowdown monitoring circuit 520；
Pixel sensing element 510 and capacitance type fingerprint testing circuit 520 one_to_one corresponding；
Pixel sensing element 510 distinguishes the most corresponding capacitance type fingerprint testing circuit 520 even
Connecing, transmission fingerprint induced signal gives the capacitance type fingerprint testing circuit 520 of its correspondence.
Wherein, above-mentioned pixel sensing element 510 is the finger of a kind of finger that can experience people
The element of line signal.
In the utility model embodiment, when carrying out fingerprint detection, the finger of people is with above-mentioned
Pixel sensing element 510 contacts, and when carrying out fingerprint detection every time, the finger of people may
With one or several pixel sensing elements 510 in above-mentioned multiple pixel sensing elements 510
Contact, and pixel sensing element 510 can sense the fingerprint on the finger of people, and generate one
Individual fingerprint induced signal, and this fingerprint induced signal is transferred to corresponding condenser type refers to
Line testing circuit 520, when condenser type receives above-mentioned pixel sense at fingerprint detection circuit 520
After answering the fingerprint induced signal that element 510 transmits, can be at capacitance type fingerprint testing circuit 520
In detecting electrode 131 on generate fingerprint capacitor, the long-pending of electric charge can be carried out in this fingerprint capacitor
Tired, generate Charge fingerprint, be integrated processing to this Charge fingerprint by integrator 140,
Obtain fingerprint signal, and by A/D converter, this fingerprint signal is converted into fingerprint data signal
Rear output.
Each pixel wherein, as an embodiment, in above-mentioned multiple pixel sensing elements
Sensing element 510 includes:
Multiple fingerprint inductors, multiple CMOS (Complementary Metal Oxide
Semiconductor, complementary metal oxide semiconductors (CMOS)) switch and emulation bus, fingerprint sense
Answer device and cmos switch one_to_one corresponding；
Fingerprint inductor is connected to above-mentioned emulation bus by corresponding cmos switch
On；
The capacitance type fingerprint detection that above-mentioned emulation bus is corresponding with above-mentioned pixel sensing element 510
Circuit 520 connects.
Wherein, each fingerprint inductor in above-mentioned multiple fingerprint inductor is provided with one
Individual cmos switch, can comprise a row fingerprint sense in above-mentioned each pixel sensing element 510
Answer device, so, when the multiple pixels sensing in fingerprint detection sensor of the above-mentioned condenser type is first
When part 510 is arranged in rows, the fingerprint inductor in this capacitance type fingerprint detection sensor is then
Two-dimensional array is arranged, in the utility model embodiment, in each pixel sensing element 510
Each fingerprint inductor in one row fingerprint inductor is connected to same by cmos switch
In a piece emulation bus, this cmos switch is used for controlling above-mentioned fingerprint inductor and CMOS
Connection between switch and disconnection.
In the utility model embodiment, the fingerprint signal of the finger of fingerprint inductor sensing people,
Produce a fingerprint induced signal, and by above-mentioned emulation bus, this fingerprint induced signal is passed
It is defeated by capacitance type fingerprint testing circuit 520, when condenser type receives at fingerprint detection circuit 520
After the fingerprint induced signal that above-mentioned emulation bus is transmitted, can be at capacitance type fingerprint testing circuit
Generate fingerprint capacitor on detecting electrode 131 in 520, electric charge can be carried out in this fingerprint capacitor
Accumulation, a Charge fingerprint can be generated, by integrator 140, this Charge fingerprint is carried out
Integral Processing, obtains fingerprint signal, and by A/D converter, this fingerprint signal is converted into finger
Export after line data signal.
The capacitance type fingerprint detection sensor that the utility model provides, it is not necessary to pass through external electrical
Pumping signal is connected on the finger of user by pole so that above-mentioned capacitance type fingerprint testing circuit
Become simple in integrated process when other equipment are combined, and add capacitance type fingerprint inspection
The application scenarios of slowdown monitoring circuit.
Embodiment 3
The utility model embodiment provides a kind of capacitance type fingerprint detection equipment.
As shown in Figure 6, the capacitance type fingerprint detection equipment bag that the utility model embodiment provides
Include:
Detection panel 610, processor 620, shell 630 and above-described embodiment 2 provide
Capacitance type fingerprint detection sensor 640；
Capacitance type fingerprint detection sensor 640 is embedded on above-mentioned detection panel 610, this detection
Panel 610 and processor 620 are installed on above-mentioned shell 630；
Capacitance type fingerprint detection sensor 640 is connected with above-mentioned processor 620, transmission fingerprint
Data signal gives above-mentioned processor 620.
In the utility model embodiment, when carrying out fingerprint detection, the finger of people and above-mentioned
Capacitance type fingerprint detection sensor 640 contacts, detection sensor 640 meeting of this capacitance type fingerprint
Gather the fingerprint signal of the finger of people, produce fingerprint induced signal, to this fingerprint induced signal
Process, finally give a fingerprint data signal, and by this fingerprint digital data transmission
To processor 620, pass when processor 620 receives capacitance type fingerprint detection sensor 640
After defeated fingerprint data signal, can be with the identity of the mark people of storage in this processor 620
Fingerprint data signal is compared, and carries out authentication, if what processor 620 received
The fingerprint signal that fingerprint data signal stores with it is consistent, then explanation authentication success, as
The fingerprint data signal that really processor 620 receives and the fingerprint letter of storage in processor 620
Number inconsistent, then explanation authentication is unsuccessful.
The capacitance type fingerprint detection equipment that the utility model provides, it is not necessary to pass through outer electrode
Pumping signal is connected on the finger of user so that capacitance type fingerprint testing circuit with its
When his equipment combines, integrated process becomes simple, and adds capacitance type fingerprint testing circuit
Application scenarios.
The above, detailed description of the invention the most of the present utility model, but of the present utility model
Protection domain is not limited thereto, and any those familiar with the art is in this practicality
In the technical scope of novel exposure, change can be readily occurred in or replace, all should contain in this reality
Within novel protection domain.Therefore, protection domain of the present utility model should be with described power
The protection domain that profit requires is as the criterion.
Claims (10)
1. a capacitance type fingerprint testing circuit, it is characterised in that including: precharge potential source,
Voltage buffer, detecting element, integrator and testing circuit plate；
Described detecting element respectively with described precharge potential source, described voltage buffer and institute
State integrator to connect, receive described precharge potential source and the voltage of described voltage buffer transmission,
And transmission fingerprint electric charge is to described integrator；
Described integrator receives the Charge fingerprint of described detecting element transmission, according to described fingerprint
Charge integration produces fingerprint signal, and exports described fingerprint signal；
Described precharge potential source, described voltage buffer, described detecting element and described integration
Device is installed on described testing circuit plate.
Capacitance type fingerprint testing circuit the most according to claim 1, it is characterised in that
Described detecting element includes: detecting electrode and isolation electrode；
Described isolation electrode is connected and institute by the first switch with described precharge potential source respectively
State voltage buffer to be connected by second switch, receive the first of the transmission of described precharge potential source
Voltage and receive described voltage buffer transmission the second voltage；
Described detecting electrode is connected with described by the 3rd switch with described isolation electrode respectively
Integrator is connected by the 4th switch.
Capacitance type fingerprint testing circuit the most according to claim 2, it is characterised in that
Described integrator includes operational amplifier, integrating condenser and the 5th switch；
The inverting input of described operational amplifier respectively with one end of described integrating condenser,
One end of described 5th switch connects, and by described 4th switch and described detecting electrode
Connect；
The output of described operational amplifier respectively with the other end and the institute of described integrating condenser
The other end stating the 5th switch connects；
The in-phase input end of described operational amplifier is connected with reference voltage source, receives described base
The reference voltage of reference voltage source transmission.
Capacitance type fingerprint testing circuit the most according to claim 3, it is characterised in that
Described testing circuit also includes A/D converter；
Described A/D converter is connected with the output of described operational amplifier, receives described fortune
Calculate the fingerprint signal of the output output of amplifier, and described fingerprint signal is converted into fingerprint
Data signal.
Capacitance type fingerprint testing circuit the most according to claim 2, it is characterised in that
Described detecting electrode is the metal electrode that the top-level metallic in described testing circuit plate is constituted.
Capacitance type fingerprint testing circuit the most according to claim 2, it is characterised in that
Described isolation electrode is the metal electrode that in described testing circuit plate, time top-level metallic is constituted, and
And described isolation electrode is U-shaped, is wrapped up by described detecting electrode.
Capacitance type fingerprint testing circuit the most according to claim 1, it is characterised in that
Described precharge potential source includes the low noise that external voltage source or described testing circuit intralamellar part produce
Acoustic-electric potential source.
8. a capacitance type fingerprint detection sensor, it is characterised in that include multiple pixel sense
Answer element and multiple capacitance type fingerprint testing circuit as described in any one of claim 1～7,
Pixel sensing element and capacitance type fingerprint testing circuit one_to_one corresponding；
The capacitance type fingerprint testing circuit connection that pixel sensing element is the most corresponding, transmission
Fingerprint induced signal gives the capacitance type fingerprint testing circuit of its correspondence.
Capacitance type fingerprint the most according to claim 8 detection sensor, it is characterised in that
Described pixel sensing element includes multiple fingerprint inductor, multiple CMOS
Cmos switch and emulation bus, fingerprint inductor and cmos switch one_to_one corresponding；
Fingerprint inductor is connected to described emulation bus by corresponding cmos switch
On；
The capacitance type fingerprint testing circuit that described emulation bus is corresponding with described pixel sensing element
Connect.
10. capacitance type fingerprint detection equipment, it is characterised in that include detecting panel,
Processor, shell and the detection sensor of the capacitance type fingerprint described in claim 8 or 9；
Described capacitance type fingerprint detection sensor is embedded on described detection panel, described detection faces
Plate and described processor are respectively mounted on the housing；
Described capacitance type fingerprint detection sensor is connected with described processor, transmission fingerprint numeral
Signal gives described processor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620075519.0U CN205540784U (en) | 2016-01-26 | 2016-01-26 | Capacitanc fingerprint detection circuit, sensor and equipment |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620075519.0U CN205540784U (en) | 2016-01-26 | 2016-01-26 | Capacitanc fingerprint detection circuit, sensor and equipment |
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|---|---|
| CN205540784U true CN205540784U (en) | 2016-08-31 |
Family
ID=56769748
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|---|---|---|---|
| CN201620075519.0U Active CN205540784U (en) | 2016-01-26 | 2016-01-26 | Capacitanc fingerprint detection circuit, sensor and equipment |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106778672A (en) * | 2016-12-30 | 2017-05-31 | 深圳芯启航科技有限公司 | A kind of fingerprint detection circuit and fingerprint detection sensor |
| CN107688798A (en) * | 2017-09-30 | 2018-02-13 | 苏州迈瑞微电子有限公司 | A kind of charge type sensor and sensor array and the acquisition methods of integrating circuit mismatch adjusting parameter with it |
-
2016
- 2016-01-26 CN CN201620075519.0U patent/CN205540784U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106778672A (en) * | 2016-12-30 | 2017-05-31 | 深圳芯启航科技有限公司 | A kind of fingerprint detection circuit and fingerprint detection sensor |
| CN106778672B (en) * | 2016-12-30 | 2023-05-05 | 深圳芯启航科技有限公司 | Fingerprint detection circuit and fingerprint detection sensor |
| CN107688798A (en) * | 2017-09-30 | 2018-02-13 | 苏州迈瑞微电子有限公司 | A kind of charge type sensor and sensor array and the acquisition methods of integrating circuit mismatch adjusting parameter with it |
| CN107688798B (en) * | 2017-09-30 | 2023-10-17 | 苏州迈瑞微电子有限公司 | Charge type sensor, sensor array with charge type sensor and acquisition method of mismatch adjustment parameters of integrating circuit |
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