CN106372605A - Noise reduction method for passive capacitance fingerprint identification system and noise reduction device - Google Patents
Noise reduction method for passive capacitance fingerprint identification system and noise reduction device Download PDFInfo
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- CN106372605A CN106372605A CN201610797763.2A CN201610797763A CN106372605A CN 106372605 A CN106372605 A CN 106372605A CN 201610797763 A CN201610797763 A CN 201610797763A CN 106372605 A CN106372605 A CN 106372605A
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
- G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
- G06V40/12—Fingerprints or palmprints
- G06V40/13—Sensors therefor
- G06V40/1306—Sensors therefor non-optical, e.g. ultrasonic or capacitive sensing
Abstract
The invention relates to a noise reduction method for a passive capacitance fingerprint identification system and a noise reduction device. The passive capacitance fingerprint identification system comprises a fingerprint sensor module and a power supply module used for providing first and second time-varying power supply voltage signals for the fingerprint sensor module, voltage difference between the first and second power supply voltage signals is kept to be constant. The noise reduction method comprises steps that whether the first power supply voltage signal jumps during a crossing power source domain data transmission process of the fingerprint sensor module is detected; if yes, crossing power source domain data transmission of the fingerprint sensor module is made to pause during a jump period. According to the system and the method, crossing power source domain data transmission between the fingerprint sensor module and the external part can be made to pause during the jump period of the power supply voltage signal of the fingerprint sensor module, and crossing power source domain data transmission errors caused by jump can be reduced or even eliminated.
Description
Technical field
It relates to fingerprint recognition field, in particular it relates to the noise-reduction method of passive type capacitive fingerprint identifying system and
Device.
Background technology
Capacitance type fingerprint identification, according to whether directly applying pumping signal on finger, can be divided into active capacitance type fingerprint
Identification and passive capacitance type fingerprint identification.The principle of active capacitance type fingerprint identification mainly applies pumping signal to increase to finger
The electric charge of strong finger surface, receives electric field signal using the induction arrays of touch panel and signal is amplified, due to fingerprint
Concavo-convex inconsistent lead to the electric field sensing also inconsistent, can take the fingerprint information accordingly.The operation principle of passive type is root
According to finger in fingerprint when on touch panel ratio shadow to touch panel internal capacitance upper/lower electrode charge distributing of ridge and paddy
The degree of sound, to obtain finger print information, additionally need not apply pumping signal to finger.In the identification of active capacitance type fingerprint, in order to keep away
Exempt from pumping signal too strong impact Consumer's Experience, excitation range signal amplitude is generally less than 4v.Due to the identification of passive capacitance type fingerprint
Technology does not need extrinsic motivated signal on finger, it is to avoid the measured sense of discomfort that large amplitude excitation signal leads to, so can
Improve the signal to noise ratio of fingerprint recognition system with the amplitude by increasing pumping signal.Passively capacitance type fingerprint identifying device is sharp
Encourage signal amplitude can more than 4v it might even be possible to using amplitude more than 15v pumping signal.
But in actually used, the increase of pumping signal amplitude certainly will require the increasing of the supply voltage of fingerprint sensor chip
Greatly, this can introduce bigger noise, thus causing data transmission fault.
Content of the invention
In view of this, present disclose provides a kind of noise-reduction method of passive type capacitive fingerprint identifying system and device, permissible
Reduce and even avoid due to the supply voltage saltus step of the fingerprint sensor module of passive type capacitive fingerprint identifying system leading to
Across power domain data transmission fault.
A kind of one side according to the embodiment of the present disclosure, there is provided noise-reduction method of passive type capacitive fingerprint identifying system,
Described passive type capacitive fingerprint identifying system includes fingerprint sensor module and for providing time-varying to fingerprint sensor module
First supply voltage signal and the supply module of the second supply voltage signal, described first supply voltage signal and the second power supply electricity
Voltage difference between pressure signal keeps constant, and described noise-reduction method includes: passes in across the power supply numeric field data of fingerprint sensor module
Detect during defeated whether the first supply voltage signal occurs saltus step；If there is saltus step in the first supply voltage signal, in institute
Suspend across the power domain data transfer of fingerprint sensor module during stating saltus step.
In certain embodiments, suspend across the power domain data transfer bag of fingerprint sensor module during described saltus step
Include: by across the power domain data transmission suspension of fingerprint sensor module for a period of time, the time span of described time-out is more than or equal to
Maximum possible bound-time.
In certain embodiments, the time span of described time-out is fixing or adjustable.
In certain embodiments, the time span of described time-out is in the range of 6ns to 100ns.
In certain embodiments, suspend across the power domain data transfer bag of fingerprint sensor module during described saltus step
Include: suspend across the power domain data transfer of fingerprint sensor module, terminate until described saltus step is detected.
In certain embodiments, whether described detection the first supply voltage signal occurs saltus step to include: by Edge check
Circuit and/or rising edge and/or the trailing edge to detect the first supply voltage signal by using Edge Detection.
In certain embodiments, described first supply voltage signal is probe power voltage signal, described second power supply
Voltage signal is sensor ground voltage signal.
In certain embodiments, described first supply voltage signal is sensor ground voltage signal, described second power supply electricity
Pressure signal is probe power voltage signal.
A kind of one side according to the embodiment of the present disclosure, there is provided denoising device of passive type capacitive fingerprint identifying system,
Described passive type capacitive fingerprint identifying system includes fingerprint sensor module and for providing time-varying to fingerprint sensor module
First supply voltage signal and the supply module of the second supply voltage signal, described first supply voltage signal and the second power supply electricity
Voltage difference between pressure signal keeps constant, and described denoising device includes: transition detection module, in fingerprint sensor module
Across power domain data transmission procedure in detect whether the first supply voltage signal occurs saltus step, if it is, triggering suspend mould
Block；Suspend module, for suspending across the power domain data transfer of fingerprint sensor module during described saltus step.
In certain embodiments, described time-out module is used for across the power domain data transmission suspension of fingerprint sensor module
For a period of time, the time span of described time-out is more than or equal to maximum possible bound-time.
In certain embodiments, the time span of described time-out is fixing or adjustable.
In certain embodiments, the time span of described time-out is in the range of 6ns to 100ns.
In certain embodiments, described module of suspending is used for suspending across the power domain data transfer of fingerprint sensor module,
Terminate until described saltus step is detected.
In certain embodiments, described transition detection module passes through edge sense circuit and/or by using Edge check
Algorithm detects rising edge and/or the trailing edge of the first supply voltage signal, to judge whether the first supply voltage signal jumps
Become.
In certain embodiments, described first supply voltage signal is probe power voltage signal, described second power supply
Voltage signal is sensor ground voltage signal.
In certain embodiments, described first supply voltage signal is sensor ground voltage signal, described second power supply electricity
Pressure signal is probe power voltage signal.
Brief description
In order to be illustrated more clearly that the technical scheme of the embodiment of the present disclosure, below by simple Jie of accompanying drawing work to embodiment
Continue it should be apparent that, the accompanying drawing in explained below only relates to some embodiments of the present disclosure, rather than restriction of this disclosure.
Fig. 1 shows the exemplary block diagram of passive capacitance type fingerprint induction system；
Fig. 2 shows probe power voltage signal vdd_sens and sensor ground in passive capacitance type fingerprint induction system
The example waveform figure of voltage signal gnd_sens；
Fig. 3 shows the example sequential of ideally gnd_sens, vdd_sens and the signal across power domain transmission
Figure；
Fig. 4 shows gnd_sens and across power domain biography in the case that gnd_sens produces glitch noise at saltus step
The example sequential chart of defeated signal；
Fig. 5 is the partial enlarged drawing of Fig. 4；
Fig. 6 is the flow chart of the noise-reduction method of the passive type capacitive fingerprint identifying system according to the embodiment of the present disclosure；
Fig. 7 is the flow chart of the noise-reduction method of the passive type capacitive fingerprint identifying system according to the embodiment of the present disclosure；
Fig. 8 is the flow chart of the noise-reduction method of the passive type capacitive fingerprint identifying system according to the embodiment of the present disclosure；
Fig. 9 is the block diagram of the denoising device of the passive type capacitive fingerprint identifying system according to the embodiment of the present disclosure；
Figure 10 shows the structure chart of edge sense circuit.
Specific embodiment
Purpose, technical scheme and advantage for making the embodiment of the present disclosure are clearer, below in conjunction with the embodiment of the present disclosure
Accompanying drawing, clear, complete description is carried out to the technical scheme of the embodiment of the present disclosure.Obviously described embodiment is the disclosure
A part of embodiment, rather than whole embodiment.Based on described embodiment of the disclosure, ordinary skill people
The every other embodiment that member is obtained on the premise of without creative work, broadly falls into the scope of disclosure protection.
Fig. 1 shows the exemplary block diagram of passive capacitance type fingerprint induction system 100.As shown in figure 1, being referred to by differential capacitive
Stricture of vagina induction system 100 includes fingerprint sensor module 101 and supply module 102.Supply module 102 welding system supply voltage vdd
(hereinafter abbreviation vdd) and system ground voltage gnd (hereinafter abbreviation gnd), and provide sensing for fingerprint sensor module 101
Device power supply voltage signal vdd_sens (hereinafter abbreviation vdd_sens) and sensor ground voltage signal gnd_sens (hereinafter letter
Claim gnd_sens).Fingerprint sensor module 101 can be realized by fingerprint sensor chip, and it can be collected with supply module 102
Become together, or discrete with supply module 102.
Fig. 2 shows the example waveform figure of vdd_sens and gnd_sens in passive capacitance type fingerprint induction system 100.As
Shown in Fig. 2, vdd_sens and gnd_sens is a pair of time varying signal with respect to systematically gnd, can be square wave, but not limit to
In this, for example, can also be sine wave or sawtooth waveforms etc..Voltage difference between vdd_sens and gnd_sens keeps constant, that is, refer to
The supply voltage of stricture of vagina sensor assembly 101 keeps constant.For example, as shown in Fig. 2 working as vdd=1.8v, during gnd=0v, vdd_
Sens is that high level is 14.8v and low level is the square-wave signal of 1.8v, and gnd_sens is high level is 13v and low level
Square-wave signal for 0v, the two synchronous saltus step, thus be the voltage stabilization of fingerprint sensor module 101 power supply in 1.8v.
Herein, with vdd as supply voltage and with gnd be with reference to ground voltage power domain be referred to as host power domain, with
Vdd_sens is supply voltage and is the power domain referred to as sens power domain with reference to ground voltage with gnd_sens.
The supply module 102 of Fig. 1 can be realized signal and change between host power domain and sens power domain, so that described
Signal transmits between this two power domain, for example, transmits between outside main control unit and fingerprint sensor module 101.Tool
Body ground, between host power domain and sens power domain, the signal of transmission will be by gnd_sens or vdd_sens modulation and demodulation.
As an example, between host power domain and sens power domain, the signal of transmission can be the spi clock signal under spi agreement
(being represented by spiclk), but it is not limited to this, it can for example be used for, with any signal, the signal controlling, communicating.
Fig. 3 shows the example sequential of ideally gnd_sens, vdd_sens and the signal across power domain transmission
Figure, wherein spiclk_host represents unmodulated spiclk signal in host power domain, and spiclk_sens represents by gnd_
Sens modulation after spiclk signal, spiclk_sens gnd_sens represent demodulated by gnd_sens after obtain in sens power domain
The spiclk signal arriving.In Fig. 3 between host power domain and sens power domain between transmission signal with spi agreement
As a example spiclk signal, but it is not limited to this, it can for example be used for, with any signal, the signal controlling, communicating.Host power domain
The example of the signal of transmission including but not limited to adopts the signal of the bus of various standard communication protocol and between sens power domain,
For example with the signal of spi communications protocol or i2c communications protocol, and other is self-defined but needs in host power domain and sens
The signal of conversion between power domain.
From figure 3, it can be seen that in the ideal case, can carry out accurately between host power domain and sens power domain
Communication.But in actual passive capacitance type fingerprint induction system, post due in the raising of pumping signal amplitude and system
The impact of the factors such as raw electrical parameter (for example, stray inductance, parasitic capacitance, dead resistance), gnd_sens and vdd_
Sens can produce glitch noise at saltus step.This glitch noise can cause the host power supply of passive capacitance type fingerprint induction system
Domain and sens power domain miscommunication, ultimately result in image acquisition failure.
Fig. 4 shows gnd_sens and across power domain biography in the case that gnd_sens produces glitch noise at saltus step
The example sequential chart of defeated signal, wherein spiclk_sens represents the spiclk signal after being modulated by gnd_sens, spiclk_
Sens gnd_sens represent demodulated by gnd_sens after sens power domain spiclk signal.Figure 4, it is seen that
Also noise in relevant position in spiclk signal after noise on gnd_sens can lead to demodulate.Fig. 5 is that the local of Fig. 4 is put
Big figure.As shown in figure 5, be respectively provided with the noise of punching or undershoot in the rising edge of gnd_sens and falling edge, with such
Gnd_sens goes to demodulate demodulated signal spiclk_sens gnd_sens obtained from spiclk_sens and can produce time domain width and divide
Not Wei t1 and t2 undershoot noise and on rush noise.T1 and t2 generally in the range of 0.5ns to 100ns, in some cases
In the range of 1ns to 10ns, typically in the range of 1ns to 6ns, this can lead to the number between host power domain and sens power domain
According to error of transmission, thus the mistake of aspect such as lead to communication, control.
In passive type capacitive fingerprint identifying system (for example, the system shown in Fig. 1), for the gnd_ of square
Sens, when square wave amplitude one timing, noise size at saltus step for the gnd_sens sends and receives node with gnd_sens
Between the difference of parasitic electrical parameter (for example, parasitic capacitance, stray inductance and/or dead resistance) and change；When described parasitism
Electrical parameter one timing, noise size at saltus step for the gnd_sens changes with the difference of square wave amplitude.So having
In the passive type capacitive fingerprint identifying system of different parasitic electrical parameters, the noise that the square wave amplitude of gnd_sens is introduced with it needs
Compromise consideration.
Although to be described as a example above using gnd_sens as modulation and demodulation signal, but those skilled in the art
It should be clear that above description is equally applicable to the situation using vdd_sens as modulated signal.
Based on above discussion, the embodiment of the present disclosure proposes a kind of noise-reduction method of passive type capacitive fingerprint identifying system
And device, by suspending fingerprint sensor module and the external world during the saltus step of the supply voltage signal of fingerprint sensor module
Across power domain data transfer, it is possible to reduce or even avoid across the power domain data transmission fault leading to due to described saltus step.
Fig. 6 is the flow chart of the noise-reduction method 600 of the passive type capacitive fingerprint identifying system according to the embodiment of the present disclosure.?
Passive type capacitive fingerprint identifying system can include fingerprint sensor module and for providing the first confession to fingerprint sensor module
Piezoelectric voltage signal and the supply module of the second supply voltage signal.In the present embodiment, can be using above with reference to Fig. 1 to Fig. 5
The passive type capacitive fingerprint identifying system of description.In certain embodiments, the first supply voltage signal can be probe power
Voltage signal vdd_sens, the second supply voltage signal can be sensor ground voltage signal gnd_sens.In other enforcements
In example, the first supply voltage signal can be sensor ground voltage signal gnd_sens, and the second supply voltage signal can be passed
Sensor power supply voltage signal vdd_sens.
In step s601, across the power domain data transmission procedure of fingerprint sensor module detects the first supply voltage letter
Number whether there is saltus step.First supply voltage signal can be probe power voltage signal vdd_sens and sensor ground voltage
Any one in signal gnd_sens.In the present embodiment, can be using gnd_sens as the first supply voltage signal.
In this step, the detection of saltus step can be realized by hardware, for example, it is possible to pass through edge sense circuit (example
As any one or more in edge sense circuit as shown in Figure 10) detecting the rising edge of the first supply voltage signal
And/or trailing edge；The detection of saltus step can also be realized by software mode, it is, for example possible to use Edge Detection is examining
Survey rising edge and/or the trailing edge of the first supply voltage signal.
In step s602, if the first supply voltage signal is detected saltus step occurs, suspending during described saltus step and referring to
Across the power domain data transfer of stricture of vagina sensor assembly.
As an example, can be described by across the power domain data transmission suspension of fingerprint sensor module for a period of time
The time span suspended is more than or equal to maximum possible bound-time.The time span suspended can be fixing or adjustable.
In certain embodiments, the time span of described time-out can be in the range of 6ns to 100ns.The time span of such as time-out can
Think 100ns.This is because, as above with reference to described in Fig. 4 and Fig. 5, the saltus step of supply voltage signal and passing across power domain
In defeated signal produce noise width generally in the range of 0.5ns to 100ns, in some cases in 1ns to 10ns model
In enclosing, typically in the range of 1ns to 6ns, so correspondingly thinking possible bound-time within this range, thus select the upper limit
100ns, as the time suspended, can farthest cover the saltus step period.But it will be understood by those skilled in the art that suspend
The selection of time span is not limited thereto, and can choose different time out length according to different noise situations, for example
50ns, 10ns or even 6ns.
As another example, across the power domain data transfer of fingerprint sensor module can be suspended, described until detecting
Saltus step terminates.Here detection saltus step being terminated, can be using various modes, to pass through Edge check as described above
Circuit is detecting, or is detected using transition detection algorithm.Generally, the beginning and end of saltus step is to be come with same detection mode
Detection.
Fig. 7 is the flow chart of the noise-reduction method 700 of the passive type capacitive fingerprint identifying system according to the embodiment of the present disclosure.Quilt
Dynamic formula capacitive fingerprint identifying system can include fingerprint sensor module and for providing the first power supply to fingerprint sensor module
Voltage signal and the supply module of the second supply voltage signal.In the present embodiment, can adopt and retouch above with reference to Fig. 1 to Fig. 5
The passive type capacitive fingerprint identifying system stated.
In step s701, fingerprint sensor module carries out across power domain data transfer.For example, as above with reference to Fig. 1 to Fig. 5
Description, carry out data transmission between host power domain and sens power domain.
In step s702, judge whether described across power domain data transfer terminates, if it is not, then execution step s703,
If DTD, flow process terminates.
In step s703, whether detection sensor ground voltage signal gnd_sens there is saltus step, if it is, execution step
S704, otherwise return to step s701.Although detect in the present embodiment is the saltus step of gnd_sens, but the enforcement of the disclosure
Example is not limited thereto, and according to the difference of applicable cases, can select in gnd_sens and vdd_sens any one or both
To be detected.
In this step, the detection of saltus step can be realized by hardware, for example, it is possible to be examined by edge sense circuit
Survey one or both of rising edge and trailing edge of the first supply voltage signal, when there is saltus step, edge sense circuit can produce
For example corresponding pulse signal is indicating this saltus step.Alternatively, the detection of saltus step can also be realized by software mode, example
As, it is possible to use Edge Detection to judge whether to occur in that one of rising edge and trailing edge or two by corresponding calculating
Person.
In step s704, judge whether described across power domain data transfer can be suspended, if it is not, execution step
S705, otherwise execution step s706.
In step s705, continue described across power domain data transfer, being then back to that step s704 continues to determine whether can
Suspend.
In step s706, suspend described across power domain data transfer.
In step s707, waiting time t0, it is then back to step s701.When time t0 is more than or equal to maximum possible saltus step
Between, so it is considered that having waited until that saltus step terminates just to continue data transfer always.T0 can be fixing or adjustable.At some
In embodiment, t0 can be in the range of 6ns to 100ns.For example, t0 can be 100ns.This is because, such as above with reference to Fig. 4 and
Fig. 5 description, the saltus step of supply voltage signal and in the signal transmitting across power domain produce noise width generally in 0.5ns
To 100ns, in some cases in the range of 1ns to 10ns, typically in the range of 1ns to 6ns, so accordingly
Possible bound-time is thought within this range in ground, thus selects upper limit 100ns as the time suspended, can farthest cover
The lid saltus step period.But it will be understood by those skilled in the art that the selection of t0 is not limited thereto, can be according to different noise feelings
Condition chooses different t0, such as 50ns, 10ns or even 6ns.
Fig. 8 is the flow chart of the noise-reduction method 800 of the passive type capacitive fingerprint identifying system according to the embodiment of the present disclosure.Quilt
Dynamic formula capacitive fingerprint identifying system can include fingerprint sensor module and for providing the first power supply to fingerprint sensor module
Voltage signal and the supply module of the second supply voltage signal.In the present embodiment, can adopt and retouch above with reference to Fig. 1 to Fig. 5
The passive type capacitive fingerprint identifying system stated.
In step s801, fingerprint sensor module carries out across power domain data transfer.For example, as above with reference to Fig. 1 to Fig. 5
Description, carry out data transmission between host power domain and sens power domain.
In step s802, judge whether described across power domain data transfer terminates, if it is not, then execution step s803,
If DTD, flow process terminates.
In step s803, whether detection sensor ground voltage signal gnd_sens there is saltus step, if it is, execution step
S804, otherwise return to step s801.Although detect in the present embodiment is the saltus step of gnd_sens, but the enforcement of the disclosure
Example is not limited thereto, and according to the difference of applicable cases, can select in gnd_sens and vdd_sens any one or both
To be detected.
In this step, the detection of saltus step can be realized by hardware, for example, it is possible to be examined by edge sense circuit
Survey one or both of rising edge and trailing edge of the first supply voltage signal, when there is saltus step, edge sense circuit can produce
For example corresponding pulse signal is indicating this saltus step.Alternatively, the detection of saltus step can also be realized by software mode, example
As, it is possible to use Edge Detection to judge whether to occur in that one of rising edge and trailing edge or two by corresponding calculating
Person.
In step s804, judge whether described across power domain data transfer can be suspended, if it is not, execution step
S805, otherwise execution step s806.
In step s805, across power domain data transfer described in continuation, and return to step s804 continue to determine whether can be temporary
Stop.
In step s806, suspend described across power domain data transfer.
In step s807, whether the saltus step of detection sensor ground voltage signal gnd_sens terminates, if it is, returning step
Rapid s801 continues data transfer, otherwise returns to step s807 and continues detection.Can be to detect saltus step using various modes
End, detected by edge sense circuit as described above, or detected using Edge Detection.In the present embodiment
In, can be using the end to detect saltus step with step 803 identical detection mode.
Fig. 9 is the block diagram of the denoising device 900 of the passive type capacitive fingerprint identifying system according to the embodiment of the present disclosure.Passively
Formula capacitive fingerprint identifying system can include fingerprint sensor module and for providing the first power supply electricity to fingerprint sensor module
Pressure signal and the supply module of the second supply voltage signal.In the present embodiment, can be using above with reference to Fig. 1 to Fig. 5 description
Passive type capacitive fingerprint identifying system.The fingerprint that denoising device 900 can be implemented in passive type capacitive fingerprint identifying system passes
In sensor module.
Denoising device 900 includes transition detection module 901 and suspends module 902.
Transition detection module 901 is used for detection first confession in across the power domain data transmission procedure of fingerprint sensor module
Whether piezoelectric voltage signal there is saltus step, if it is, triggering suspends module 902.Transition detection module 901 can by hardware or
Software detection mode is realizing the detection of saltus step.For example, it is possible to detect the first supply voltage signal using edge sense circuit
Rising edge and/or trailing edge, or detected using Edge Detection the first supply voltage signal rising edge and/or under
Fall edge.
Suspend module 902 to be used for suspending across the power domain data transfer of fingerprint sensor module during described saltus step.Make
For an example, suspending module 902 can be described by across the power domain data transmission suspension of fingerprint sensor module for a period of time
The time span suspended is more than or equal to maximum possible bound-time.For example, it is possible to be realized above-mentioned temporary by setting timer
Between the stopping time.In certain embodiments, the time span of described time-out can be 100ns.This is because, such as above with reference to Fig. 4 and
Fig. 5 description, the saltus step of supply voltage signal and in the signal transmitting across power domain produce noise width generally in 0.5ns
To 100ns, in some cases in the range of 1ns to 10ns, typically in the range of 1ns to 6ns, so accordingly
Possible bound-time is thought within this range in ground, thus selects maximum 100ns as the time suspended, can be at utmost
Ground covers the saltus step period.But it will be understood by those skilled in the art that the selection of time out length is not limited thereto, Ke Yigen
Choose the different time out length in the range of such as 6ns to 100ns according to different noise situations, such as 50ns, 10ns or
Even 6ns.
As another example, suspend across the power domain data transfer that module 902 can suspend fingerprint sensor module, until
Described saltus step is detected to terminate.Here detection saltus step being terminated can be executed by transition detection module 901, as described above
Detected by edge sense circuit, or detected using transition detection algorithm.Generally, the beginning and end of saltus step is with same
The detection mode of sample is detecting.
Figure 10 shows the structure of edge sense circuit, and wherein Figure 10 a shows the structure of rising edge testing circuit 1001
With corresponding signal timing diagram, Figure 10 b shows the structure of trailing edge testing circuit 1002 and corresponding signal timing diagram, figure
10c shows double structures along testing circuit 1003 and corresponding sequential chart.
As shown in Figure 10 a, rising edge testing circuit 1001 include " with (and) " gate 1001-1, phase inverter 1001-2,
Resistor 1001-3 and capacitor 1001-4.Input signal vin be divided into two-way be connected respectively to and door 1001-1 input a,
B, a road vin are directly connected to the input a of and door 1001-1, and another road vin is via the phase inverter 1001-2 connecting and resistance
Device 1001-3 is connected to the input b of and door 1001-1, and the input b of and door 1001-1 connects via capacitor 1001-4
Ground.In figure vaRepresent the signal at the input a of and door 1001-1, vbRepresent the signal at the input b of and door 1001-1,
Vout represents the output signal at the outfan o of and door 1001-1.As shown in Figure 10 a, only on input signal vin is in
Rise along when, vaAnd vbIt is high level simultaneously, thus output signal vout at the outfan o of and door 1001-1 is high level, and
It is low level in other moment output signals vout.So, when input signal vin is in rising edge, output signal vout
In can produce a pulse signal, indicate the appearance of this rising edge.
As shown in fig. lob, trailing edge testing circuit 1002 include " with (and) " gate 1002-1, phase inverter 1002-2,
1002-3 and 1002-4, resistor 1002-5 and capacitor 1002-6.Input signal vin is divided into two-way and is connected respectively to and door
Input a, b of 1002-1, a road vin are connected to the input a of and door 1002-1, another road vin through phase inverter 1002-2
It is connected to the input b of and door 1002-1 after phase inverter 1002-3 and 1002-4 and resistor 1002-5 of cascade, and
And the input b of and door 1002-1 is grounded via capacitor 1002-6.In figure vaRepresent at the input a of and door 1001-1
Signal, vbRepresent the signal at the input b of and door 1001-1, vout represents the output at the outfan o of and door 1002-1
Signal.As shown in fig. lob, only when input signal vin is in trailing edge, vaAnd vbIt is high level simultaneously, thus and door
Output signal vout at the outfan o of 1002-1 is high level, and is low level in other moment output signals vout.This
Sample, when input signal vin is in trailing edge, can produce a pulse signal, indicate this trailing edge in output signal vout
Occur.
As shown in figure l oc, double " XOR (xor) " gate 1003-1, resistor 1003-2 are included along testing circuit 1003
With capacitor 1003-3.Input signal vin is divided into input a, b that two-way is connected respectively to xor door 1003-1, and a road vin is straight
It is connected to the input a of xor door 1003-1 in succession, another road vin is connected to xor door 1003-1 via the resistor 1003-2 of series connection
Input b, and the input b of xor door 1003-1 via capacitor 1003-3 be grounded.In figure vaRepresent xor door 1003-1
Signal at input a, vbRepresent the signal at xor door 1003-1 input b, vout represents the outfan o of xor door 1003-1
The output signal at place.As shown in Figure 10, only when input signal vin is in rising edge or trailing edge, vaAnd vbIn one be
High level and another be low level, thus the output signal vout outfan o of xor door 1003-1 at be high level, and
Other moment output signals vout are low level.So, when input signal vin is in rising edge or trailing edge, output letter
A pulse signal can be produced in number vout, indicate the appearance of this rising edge or trailing edge.
The edge sense circuit of Figure 10 can be separately provided it is also possible to be arranged in fingerprint sensor module.In the disclosure
Embodiment in, saltus step can be realized using any one or more in the edge sense circuit shown in Figure 10 a to Figure 10 c
Detection.
Will be consequently realised that in conjunction with the analysis above with reference to Fig. 1 to Fig. 5, the jump of the supply voltage signal of fingerprint sensor module
Upper punching and/or undershoot noise accordingly is produced, this may cause data to pass in the signal across power domain transmission that change can lead to
Defeated mistake, embodiment of the disclosure is passed through to suspend the data transfer across power domain during the saltus step of supply voltage signal, can
To reduce or even to avoid across the power domain data transmission fault leading to due to described saltus step.
Embodiment of the disclosure can make the data transfer across power domain avoid fingerprint sensing by setting time out
The saltus step period of the supply voltage signal of device module, the selection of time out is flexible, certain value can be fixed on it is also possible to
According to circumstances make adjustment, as long as it meets more than or equal to maximum possible bound-time.
Alternatively, embodiment of the disclosure can also make the number across power domain by detecting the beginning and end of saltus step
Avoid the saltus step period of the supply voltage signal of fingerprint sensor module according to transmission, when this relatively accurately can determine saltus step
Section, thus be more effectively carried out data transfer.
Embodiment of the disclosure can detect the jump of the supply voltage signal of fingerprint sensor module by various modes
Become, for example, to be detected by way of hardware or software.In addition, embodiment of the disclosure not only can be to fingerprint sensor module
The saltus step of power source supplying voltage signal detected it is also possible to the saltus step to the ground voltage signal of fingerprint sensor module is carried out
Detection, or even both all can be detected.In actual applications, the side of detection accordingly can according to circumstances be selected
Formula and detection object.
The foregoing is only preferred embodiment of the present disclosure, be not limited to the disclosure, for those skilled in the art
For, the disclosure can have various change and change.Any modification of being made within all spirit in the disclosure and principle, equivalent
Replace, improve etc., should be included within the protection domain of the disclosure.
Claims (16)
1. a kind of noise-reduction method of passive type capacitive fingerprint identifying system, described passive type capacitive fingerprint identifying system includes fingerprint
Sensor assembly and the first supply voltage signal from time-varying to fingerprint sensor module and the second supply voltage signal for providing
Supply module, voltage difference between described first supply voltage signal and the second supply voltage signal keeps constant, described fall
Method for de-noising includes:
Detect whether the first supply voltage signal occurs saltus step in across the power domain data transmission procedure of fingerprint sensor module；
If first supply voltage signal occur saltus step, during described saltus step suspend fingerprint sensor module across power domain
Data transfer.
2. noise-reduction method according to claim 1, wherein, during described saltus step suspend fingerprint sensor module across electricity
Source domain data transfer includes:
By across the power domain data transmission suspension of fingerprint sensor module for a period of time, the time span of described time-out is more than or equal to
Maximum possible bound-time.
3. noise-reduction method according to claim 2, wherein, the time span of described time-out is fixing or adjustable.
4. noise-reduction method according to claim 2, wherein, the time span of described time-out is in the range of 6ns to 100ns.
5. noise-reduction method according to claim 1, wherein, during described saltus step suspend fingerprint sensor module across electricity
Source domain data transfer includes:
Suspend across the power domain data transfer of fingerprint sensor module, terminate until described saltus step is detected.
6. noise-reduction method according to claim 1, wherein, whether described detection the first supply voltage signal there is saltus step bag
Include: detect by edge sense circuit and/or by using Edge Detection the first supply voltage signal rising edge and/
Or trailing edge.
7. the noise-reduction method according to any one of claim 1 to 6 claim, wherein, described first supply voltage letter
Number be probe power voltage signal, described second supply voltage signal be sensor ground voltage signal.
8. noise-reduction method according to any one of claim 1 to 6, wherein, described first supply voltage signal is sensing
Device ground voltage signal, described second supply voltage signal is probe power voltage signal.
9. a kind of denoising device of passive type capacitive fingerprint identifying system, described passive type capacitive fingerprint identifying system includes fingerprint
Sensor assembly and the first supply voltage signal from time-varying to fingerprint sensor module and the second supply voltage signal for providing
Supply module, voltage difference between described first supply voltage signal and the second supply voltage signal keeps constant, described fall
Device of making an uproar includes:
Transition detection module, for detecting the first supply voltage in across the power domain data transmission procedure of fingerprint sensor module
Whether signal there is saltus step, if it is, triggering suspends module；
Suspend module, for suspending across the power domain data transfer of fingerprint sensor module during described saltus step.
10. denoising device according to claim 9, wherein, described time-out module be used for by fingerprint sensor module across
For a period of time, the time span of described time-out is more than or equal to maximum possible bound-time to power domain data transmission suspension.
11. denoising devices according to claim 10, wherein, the time span of described time-out is fixing or adjustable.
12. denoising devices according to claim 10, wherein, the time span of described time-out is in 6ns to 100ns scope
Interior.
13. denoising devices according to claim 9, wherein, described time-out module is used for suspending fingerprint sensor module
Across power domain data transfer, terminates until described saltus step is detected.
14. denoising devices according to claim 9, wherein, described transition detection module pass through edge sense circuit and/or
Detect rising edge and/or the trailing edge of the first supply voltage signal by using Edge Detection, to judge the first power supply electricity
Whether pressure signal there is saltus step.
15. denoising devices according to any one of claim 9 to 14 claim, wherein, described first supply voltage
Signal is probe power voltage signal, and described second supply voltage signal is sensor ground voltage signal.
16. denoising devices according to any one of claim 9 to 14, wherein, described first supply voltage signal is to pass
Sensor ground voltage signal, described second supply voltage signal is probe power voltage signal.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2018177104A1 (en) * | 2017-04-01 | 2018-10-04 | 京东方科技集团股份有限公司 | Fingerprint identification device, display substrate and display device |
| CN108780503A (en) * | 2018-02-12 | 2018-11-09 | 深圳市汇顶科技股份有限公司 | Fingerprint detection circuit, fingerprint identification device and terminal device |
| CN111566963A (en) * | 2017-11-10 | 2020-08-21 | 弗劳恩霍夫应用研究促进协会 | Data transmitter and data receiver with low time delay for telegram splitting transmission method |
| CN112424786A (en) * | 2018-07-10 | 2021-02-26 | 索尼公司 | Signal processing circuit, signal processing apparatus, and signal processing method |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101697244A (en) * | 2009-09-08 | 2010-04-21 | 上海工程技术大学 | Fingerprint-based remote control system and remote control method thereof |
| CN102844669A (en) * | 2010-08-24 | 2012-12-26 | 赛普拉斯半导体公司 | Noise suppression circuits and methods for capacitance sensing systems |
| CN102857245A (en) * | 2011-06-30 | 2013-01-02 | 意法半导体研发(深圳)有限公司 | LIN (local Internet) receiver for providing immunity against ISO (interrupted source output) pulse |
| CN104748770A (en) * | 2013-12-27 | 2015-07-01 | 比亚迪股份有限公司 | Capacitance detection device used for fingerprint identification and fingerprint identification device provided with same |
| CN105448247A (en) * | 2016-01-04 | 2016-03-30 | 京东方科技集团股份有限公司 | Method and apparatus for modulating backlight source, lamp strip, backlight module, and display apparatus |
-
2016
- 2016-08-31 CN CN201610797763.2A patent/CN106372605B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101697244A (en) * | 2009-09-08 | 2010-04-21 | 上海工程技术大学 | Fingerprint-based remote control system and remote control method thereof |
| CN102844669A (en) * | 2010-08-24 | 2012-12-26 | 赛普拉斯半导体公司 | Noise suppression circuits and methods for capacitance sensing systems |
| CN102857245A (en) * | 2011-06-30 | 2013-01-02 | 意法半导体研发(深圳)有限公司 | LIN (local Internet) receiver for providing immunity against ISO (interrupted source output) pulse |
| CN104748770A (en) * | 2013-12-27 | 2015-07-01 | 比亚迪股份有限公司 | Capacitance detection device used for fingerprint identification and fingerprint identification device provided with same |
| CN105448247A (en) * | 2016-01-04 | 2016-03-30 | 京东方科技集团股份有限公司 | Method and apparatus for modulating backlight source, lamp strip, backlight module, and display apparatus |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2018177104A1 (en) * | 2017-04-01 | 2018-10-04 | 京东方科技集团股份有限公司 | Fingerprint identification device, display substrate and display device |
| US10817699B2 (en) | 2017-04-01 | 2020-10-27 | Boe Technology Group Co., Ltd. | Fingerprint recognition device, display substrate and display apparatus |
| CN111566963A (en) * | 2017-11-10 | 2020-08-21 | 弗劳恩霍夫应用研究促进协会 | Data transmitter and data receiver with low time delay for telegram splitting transmission method |
| CN111566963B (en) * | 2017-11-10 | 2023-06-30 | 弗劳恩霍夫应用研究促进协会 | Data transmitter and data receiver and method for transmitting and receiving data |
| US11909519B2 (en) | 2017-11-10 | 2024-02-20 | Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V. | Data transmitter and data receiver with low latency for the telegram splitting transfer method |
| CN108780503A (en) * | 2018-02-12 | 2018-11-09 | 深圳市汇顶科技股份有限公司 | Fingerprint detection circuit, fingerprint identification device and terminal device |
| CN108780503B (en) * | 2018-02-12 | 2022-05-03 | 深圳市汇顶科技股份有限公司 | Fingerprint detection circuit, fingerprint identification device and terminal equipment |
| CN112424786A (en) * | 2018-07-10 | 2021-02-26 | 索尼公司 | Signal processing circuit, signal processing apparatus, and signal processing method |
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|---|---|
| CN106372605B (en) | 2019-10-15 |
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