CN109889189A - A kind of active pull-up circuit based on fingerprint sensor acquisition array output stage - Google Patents
A kind of active pull-up circuit based on fingerprint sensor acquisition array output stage Download PDFInfo
- Publication number
- CN109889189A CN109889189A CN201910338671.1A CN201910338671A CN109889189A CN 109889189 A CN109889189 A CN 109889189A CN 201910338671 A CN201910338671 A CN 201910338671A CN 109889189 A CN109889189 A CN 109889189A
- Authority
- CN
- China
- Prior art keywords
- nmos tube
- dummy
- acquisition point
- fingerprint sensor
- output stage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000003990 capacitor Substances 0.000 claims description 17
- 230000005611 electricity Effects 0.000 claims description 17
- 230000003321 amplification Effects 0.000 claims description 12
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 12
- 238000000034 method Methods 0.000 claims description 6
- 230000001133 acceleration Effects 0.000 claims description 5
- 239000011800 void material Substances 0.000 claims description 4
- 230000004044 response Effects 0.000 claims description 3
- 241001481828 Glyptocephalus cynoglossus Species 0.000 claims 1
- 239000004065 semiconductor Substances 0.000 abstract description 4
- 238000010586 diagram Methods 0.000 description 9
- 230000003071 parasitic effect Effects 0.000 description 9
- 238000012545 processing Methods 0.000 description 4
- 230000001052 transient effect Effects 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 3
- 230000005284 excitation Effects 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000037361 pathway Effects 0.000 description 2
- 241000208340 Araliaceae Species 0.000 description 1
- 235000005035 Panax pseudoginseng ssp. pseudoginseng Nutrition 0.000 description 1
- 235000003140 Panax quinquefolius Nutrition 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 235000008434 ginseng Nutrition 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000013139 quantization Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 230000007480 spreading Effects 0.000 description 1
Landscapes
- Image Input (AREA)
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
- Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
Abstract
The invention discloses a kind of active pull-up circuits based on fingerprint sensor acquisition array output stage, it is related to semiconductor chip field, including current source and auxiliary discharge access, auxiliary discharge access and current source are in parallel, auxiliary discharge access one end connects the electric discharge node of fingerprint sensor acquisition array, other end ground connection, auxiliary discharge access carry out repid discharge to electric discharge node in the case where fingerprint sensor acquires array reset state.The present invention increases auxiliary discharge access by improving active pull-up circuit on the basis of current source, improves the charge velocity of discharge on electric discharge node, shortens the resetting time of each collection point, improve the acquisition speed of fingerprint image, reduce the distortion factor of image.
Description
Technical field
The present invention relates to semiconductor chip fields more particularly to a kind of semiconductor fingerprint sensor to acquire array output stage
Active pull-up circuit.
Background technique
Existing semiconductor fingerprint sensor is made of acquisition array and signal processing circuit mostly.Pass through point by point scanning
Mode, finger print information is converted to analog voltage signal one by one by acquisition array, by the filtering of signal processing circuit, amplification,
Analog-to-digital conversion and data transmission, host computer are spliced again by acquisition order, are obtained after the data for receiving each point
One width represents the gray level image of finger print information.According to the processing capacity of different fingerprint algorithms, security level and relevant industries standard,
The size for acquiring array is also different, and common acquisition array size has 160 × 160,192 × 192 etc..In acquisition array
In, each collection point is carried out choosing control by row address and column address signal.Row, column address point enabled simultaneously, is selected
Carry out Image Acquisition.Each collection point includes an output driving pipe alone, and the output driving pipe of all collection points is final
It brings together, forms an output common node.Due to the collection point enormous amount in acquisition array, output driving pipe and defeated
Conducting wire accumulation is very big in the parasitic capacitance of common node out, and the task of output driving pipe is to that this capacitor is operated alone,
By the small signal of effective fingerprint, (capacitance is directly converted to the voltage signal come between collection point and finger print, due to signal
Amplitude it is small, in the range of signal intensity, the gain of late-class circuit can be approximately steady state value.Relative to the variation of the signal,
Late-class circuit can be equivalent to linear circuit) transmission come out.The output of all output driving pipes shares an active load, this is active
The main function of load is to provide necessary biasing to the output driving pipe in selected collection point (normally to put even if circuit is in
The quiescent operation voltage value of big state, near the voltage value, the gain approximately constant of circuit), guarantee the acquisition each chosen
Point is in reset state and fingerprint collecting state, the normal bias of output stage.Existing active pull-up circuit, usually by one
Common current source is formed.When selected collection point is in reset state, current source discharges to common node, due to general
Logical current source can only provide constant current offset, and the charge velocity of discharge on common node is limited, substantially prolong each
The resetting time of collection point reduces the acquisition speed of acquisition array.If it is Q that array, which exports the charge on common node, minimum
Discharge time Tmin=Q/I, I are current offset.In acquisition array, the physical location of each collection point is different, bears to active
The physical distance of load is also different, and the dead resistance and capacitor for resulting in each collection point to active load are different, active load
Choose the velocity of discharge of collection point also different each.If not staying enough enough resetting times, will lead to apart from public
Node is remote, and dead resistance and the big collection point of parasitic capacitance reset the fingerprint quantization error insufficient, acquisition is caused to export.
Therefore, those skilled in the art is dedicated to developing a kind of based on the active of fingerprint sensor acquisition array output stage
Load circuit reaches the acquisition speed for improving fingerprint image, reduces the purpose of the distortion factor of image.
Summary of the invention
In view of the above drawbacks of the prior art, how the technical problems to be solved by the invention improve adopting for fingerprint image
Collect speed, reduces the distortion factor of image.
To achieve the above object, inventor it has been investigated that, existing active pull-up circuit is usually common by one
Current source is formed.When selected collection point is in reset state, electric discharge node of the current source to fingerprint sensor acquisition array
It discharges, since common current source can only provide constant current offset, the charge velocity of discharge discharged on node is limited,
The resetting time for substantially prolonging each collection point reduces the acquisition speed of acquisition array.To improve adopting for fingerprint image
Collect speed, needs to set about from the charge velocity of discharge improved on electric discharge node.Inventor considers to increase on the basis of current source auxiliary
Discharge path is helped, to improve the charge velocity of discharge on electric discharge node, shortens the resetting time of each collection point.Thus, at this
In the embodiment one of invention, a kind of active pull-up circuit based on fingerprint sensor acquisition array output stage, including electricity are provided
Stream source and auxiliary discharge access, auxiliary discharge access and current source are in parallel, and auxiliary discharge access one end connection fingerprint sensor is adopted
Collect the electric discharge node of array, other end ground connection, auxiliary discharge access is in the case where fingerprint sensor acquires array reset state to electric discharge
Node carries out repid discharge.
Optionally, in the active pull-up circuit based on fingerprint sensor acquisition array output stage in the above-described embodiments,
Above-mentioned current source includes power supply, current source PMOS tube and current mirror, and current mirror includes that current mirror input NMOS tube and current mirror are defeated
NMOS tube out, the source electrode of current source PMOS tube connect power supply, and the grid of current source PMOS tube accesses bias voltage VBP, current source
The drain electrode of the drain electrode connection current mirror input NMOS tube of PMOS tube, current mirror inputs NMOS tube grid and current mirror exports NMOS tube
Grid be connected, the drain electrode that current mirror exports NMOS tube connects above-mentioned electric discharge node, and current mirror inputs NMOS tube and current mirror is defeated
The source electrode ground connection of NMOS tube out.
In the embodiment of the present invention two, a kind of structure of auxiliary discharge access is strong discharge path, including is discharged by force
NMOS tube, the grid incoming control signal of Qiang Fang electricity NMOS tube, the source electrode ground connection of Qiang Fang electricity NMOS tube, the leakage of Qiang Fang electricity NMOS tube
Pole connection electric discharge node.
Further, the active pull-up circuit based on fingerprint sensor acquisition array output stage in the above-described embodiments
In, the structure of the auxiliary discharge access enables the strong discharge path in the case where fingerprint sensor acquires array reset state, that is,
The control signal of the grid of strong electric discharge NMOS tube becomes high level, controls strong electric discharge NMOS transistor conduction, makes the strong electric discharge NMOS tube
In triode region, the strong electric discharge NMOS tube is equivalent to a small resistance at this time, rapidly leads to the charge of above-mentioned electric discharge node
It crosses the strong electric discharge NMOS tube and is quickly released to ground；Before entering fingerprint collecting state (latter half of reset state), close
The strong discharge path, that is, the control signal of grid of the strong electric discharge NMOS tube become low level, export NMOS in current mirror
Under the normal bias of pipe, the output driving pipe driving parasitic capacitance that fingerprint sensor acquisition array is selected in collection point is quickly returned
To normal bias condition, it is ready for the fingerprint collecting state of next stage.As can be seen that the type auxiliary discharge access exists
When enabling the strong discharge path, biggish transient current can be generated, which can power supply to fingerprint sensor and ground note
Enter noise.But, biggish transient current will not influence the normal use of fingerprint collecting sensor, only theoretically exist
Defect.
In the embodiment of the present invention three, another structure of improving of auxiliary discharge access includes dummy acquisition point
(dummypixel), dummy acquisition point output stage current source NMOS tube, operational amplifier and auxiliary conducting NMOS tube, dummy acquisition
Point (dummy pixel) connects and generates reference voltage VREF with the drain electrode of dummy acquisition point output stage current source NMOS tube, ginseng
Reversed input of the voltage VREF as operational amplifier is examined, the positive input of operational amplifier connects electric discharge node, operational amplifier
Output connection auxiliary conducting NMOS tube grid, the drain electrode connection electric discharge node of auxiliary conducting NMOS tube, dummy acquisition point is defeated
The grid of grid with current mirror the output NMOS tube of grade current source NMOS tube is connected out, dummy acquisition point output stage current source NMOS
The source electrode of pipe and the source electrode ground connection of auxiliary conducting NMOS tube.
Further, the active pull-up circuit based on fingerprint sensor acquisition array output stage in the above-described embodiments
In, auxiliary conducting NMOS tube is N-type MOS transistor, and the output of operational amplifier controls auxiliary conducting NMOS tube
On state, specifically, operational amplifier calculate electric discharge node voltage and reference voltage VREF difference, when difference is greater than
When 0, the output voltage of operational amplifier increases the ducting capacity of auxiliary conducting NMOS tube, enhances the electric discharge to the electric discharge node
Ability gradually becomes smaller in response to difference, and the output voltage of operational amplifier reduces the ducting capacity of auxiliary conducting NMOS tube, weakens
To the discharge capability of electric discharge node, when difference is equal to 0, the fingerprint sensor collection point output driving pipe chosen of acquisition array into
Enter normal bias state.
In the embodiment of the present invention four, above-mentioned auxiliary discharge access is advanced optimized, current mirror is exported into NMOS tube
Power supply/conducting NMOS tube is merged into auxiliary conducting NMOS tube, timesharing switching control is carried out using switch.
Further, the active pull-up circuit based on fingerprint sensor acquisition array output stage in the above-described embodiments
In, auxiliary discharge access includes dummy acquisition point (dummy pixel), dummy acquisition point output stage current source NMOS tube, operation
Amplifier accelerates discharge switch, normal bias switch and power supply/conducting NMOS tube, dummy acquisition point (dummy pixel) and void
The drain electrode of quasi- collection point output stage current source NMOS tube connects and generates reference voltage VREF, and reference voltage VREF is put as operation
The reversed input of big device, the positive input of operational amplifier connect the electric discharge node, the output connection power supply of operational amplifier/lead
The grid of logical NMOS tube, power supply/conducting NMOS tube drain electrode connection electric discharge node, dummy acquisition point output stage current source NMOS tube
Grid be connected with power supply/conducting NMOS tube grid, the source electrode and power supply of dummy acquisition point output stage current source NMOS tube/lead
The source electrode ground connection of logical NMOS tube, accelerates discharge switch to be set to output and the power supply/conducting NMOS tube grid of operational amplifier
Between, normal bias switchs the grid and power supply/conducting NMOS tube for being set to dummy acquisition point output stage current source NMOS tube
Between grid.
Further, the active pull-up circuit based on fingerprint sensor acquisition array output stage in the above-described embodiments
In, switch carries out timesharing switching control and refers to when fingerprint sensor acquires the collection point that array is chosen and enters reset state, adds
Fast discharge switch closure, normal bias switch disconnect, and operational amplifier and power supply/conducting NMOS tube form feedback loop, electricity
Source/conducting NMOS tube serves as auxiliary conducting NMOS tube, carries out repid discharge to above-mentioned electric discharge node, makes the electricity of the electric discharge node
Pressure quickly recovers to the reference voltage VREF；When the collection point that fingerprint sensor acquisition array is chosen enters fingerprint collecting
When state, discharge switch is accelerated to disconnect, normal bias closes the switch, and power supply/conducting NMOS tube serves as current mirror output NMOS tube,
The collection point that array is chosen is acquired for fingerprint sensor, and constant current biasing is provided.
Optionally, the active load electricity based on fingerprint sensor acquisition array output stage in above-described embodiment three and four
Lu Zhong, dummy acquisition point (dummy pixel) include dummy acquisition point ratio enlargement capacitor, dummy acquisition point inside amplification electricity
Road, dummy acquisition point row selection control pipe, dummy acquisition point column selection control pipe, dummy acquisition point output driving pipe and virtually adopt
Collect point source, dummy acquisition point ratio enlargement capacitor and dummy acquisition point internal amplification circuit are connected in parallel, dummy acquisition point ratio
Example amplification capacitor both ends are short-circuited, and dummy acquisition point internal amplification circuit connects the grid of dummy acquisition point output driving pipe, institute
The drain electrode for stating dummy acquisition point output driving pipe connects the dummy acquisition point source, the dummy acquisition point output driving pipe
Source electrode connects the drain electrode of the dummy acquisition point row selection control pipe, the source electrode connection of the dummy acquisition point row selection control pipe
The source electrode connection of the drain electrode of the dummy acquisition point column selection control pipe, the dummy acquisition point column selection control pipe is described virtual
The drain electrode of collection point output stage current source NMOS tube, the dummy acquisition point row selection control pipe and the dummy acquisition point column selection
The grid for selecting control pipe connects the dummy acquisition point source, the dummy acquisition point row selection control pipe and the dummy acquisition
Point column selection control pipe is in normally on.
The present invention provides a kind of fingerprint sensors, acquire battle array based on fingerprint sensor using in any of the above-described embodiment
The active pull-up circuit of column output stage.
The present invention provides a kind of circuits, use the fingerprint sensor in above-described embodiment.
The present invention increases auxiliary discharge access on the basis of current source, improves electric discharge by improving active pull-up circuit
The charge velocity of discharge on node, shortens the resetting time of each collection point, improves the acquisition speed of fingerprint image, reduces
The distortion factor of image.
It is described further below with reference to technical effect of the attached drawing to design of the invention, specific structure and generation, with
It is fully understood from the purpose of the present invention, feature and effect.
Detailed description of the invention
Fig. 1 is the conventional fingerprint sensor acquisition array and output schematic diagram illustrated accoding to exemplary embodiment；
Fig. 2 is the conventional active pull-up circuit schematic diagram illustrated accoding to exemplary embodiment；
Fig. 3 is the auxiliary discharge access schematic diagram illustrated accoding to exemplary embodiment；
Fig. 4 is the auxiliary discharge access schematic diagram illustrated accoding to exemplary embodiment；
Fig. 5 is the auxiliary discharge access schematic diagram illustrated accoding to exemplary embodiment；
Fig. 6 is the auxiliary discharge access schematic diagram illustrated accoding to exemplary embodiment；
Fig. 7 is the fingerprint sensor schematic diagram illustrated accoding to exemplary embodiment；
Fig. 8 is the circuit diagram illustrated accoding to exemplary embodiment.
Specific embodiment
Multiple preferred embodiments of the invention are introduced below with reference to Figure of description, keep its technology contents more clear and just
In understanding.The present invention can be emerged from by many various forms of embodiments, and protection scope of the present invention not only limits
The embodiment that Yu Wenzhong is mentioned.
In the accompanying drawings, the identical component of structure is indicated with same numbers label, everywhere the similar component of structure or function with
Like numeral label indicates.The size and thickness of each component shown in the drawings are to be arbitrarily shown, and there is no limit by the present invention
The size and thickness of each component.Apparent in order to make to illustrate, some places schematically suitably exaggerate component in attached drawing
Thickness.
In order to improve the acquisition speed of fingerprint image, the distortion factor of image is reduced, inventor has studied conventional fingerprint sensing
Device acquires the course of work of acquisition dot circuit during array and the circuit structure and fingerprint collecting of output.Fig. 1 is routinely to refer to
The acquisition of line sensor array and output schematic diagram, conventional fingerprint sensor 100 include the single collection point in fingerprint collecting array
101, a line collection point 102 for being made of several collection points, one be made of several collection points column collection point 103, several
Acquisition array 104, finger excitation signal 105, the finger equivalent capacity 106, ratio enlargement capacitor that a column collection point is constituted
107, collection point internal amplification circuit 108, reset switch 109, collection point output driving pipe 110, row selection control pipe 111
(ROW_SEL), column selection control pipe 113 (COLUMN_SEL), (the i.e. output of fingerprint sensor acquisition array of electric discharge node 115
Common node), active pull-up circuit 116, electric discharge node 115 on parasitic capacitance 118, fingerprint sensor acquisition array rear class drive
Dynamic device 119, the output end 120 of fingerprint sensor acquisition array, acquisition point source 112, in addition there are also the ground connection of fingerprint sensor
End 117 and 121.The size of parasitic capacitance 118 determines that quantity is bigger by the quantity of collection point in fingerprint sensor acquisition array,
Device and cabling on electric discharge node 115 is more, and the capacitance of parasitic capacitance 118 is bigger.Row selection control pipe 111 exports
Row selection control signal 112, column selection control the output column selection of pipe 113 and control signal 114.
The course of work of conventional fingerprint sensor 100 is described as follows, when row selects control signal 112 and column selection control letter
Numbers 114 when being high level simultaneously, and row select control pipe 111 and column selection control pipe 113 to simultaneously turn on as switch, and expression is currently
Collection point is selected.After choosing collection point, reset switch 109 is connected first, and integrated circuit enters multiple in the collection point chosen
Position state, collection point output driving pipe 110 is under the conditions of the normal bias of active pull-up circuit 116, as follower, makes to discharge
The state of node 115 follows the resetting voltage inside collection point.Electric discharge node 115 follows the process of Voltage Establishment, is active negative
The process that the charge that circuit 116 resides in parasitic capacitance 118 last moment discharges is carried, electric discharge node 115 follows electricity
The speed that pressure is established depends on the size of parasitic capacitance 118 and the size of current of active pull-up circuit 116.Reset state terminate with
Afterwards, reset switch 109 disconnects, which enters fingerprint collecting state, and load finger excitation signal 105 passes through the equivalent electricity of finger
Hold 106 and the progress of ratio enlargement capacitor 107 ratio enlargement (or reducing), is transmitted the small signal of fingerprint by output driving pipe 110
To the surface of outside fingerprint collecting array, exported after being driven using fingerprint sensor acquisition array rear class driver 119.
When reset switch 109 is connected, acquisition dot circuit is in reset state, establishes normal quiescent operation inside circuit
Point.When reset switch 109 disconnects, acquisition dot circuit enters fingerprint collecting state, and the capacitor between collection point and finger print is turned
Formation voltage.Circuit works near a upper quiescent point.(selection control pipe at once is being chosen by address signal in collection point
111 and column selection control pipe 113 as switch simultaneously turn on when) after, be introduced into reset state, then carry out fingerprint collecting.
Specifically, fingerprint collecting process specifically includes that 1, chooses collection point, at once selection control pipe 111 and column selection control
Tubulation 113 simultaneously turns on selected collection point, referred to as effective collection point；2, collection point circuit reset, acquisition dot circuit are in multiple
Position state, acquisition dot circuit establish normal quiescent point, meanwhile, the charge on ratio enlargement capacitor 107 is reset；3, refer to
Line acquisition, acquisition dot circuit enter fingerprint collecting state, acquire dot circuit in quiescent point and are implemented around capacitor to voltage
Conversion.Output voltage Vo=Vi*Cf/Ca, wherein Vi is the amplitude of finger excitation signal 105, and Cf is finger equivalent capacity 106,
Ca is ratio enlargement capacitor 107.
Inventor further analyzes conventional active pull-up circuit, as shown in Fig. 2, active pull-up circuit 116 be usually by
One common current source is formed, including power supply 201, current source PMOS tube 202 and current mirror 200, and current mirror 200 includes electric current
Mirror inputs NMOS tube 204 and current mirror exports NMOS tube 205, and the source electrode of current source PMOS tube 202 connects power supply 201, current source
The grid of PMOS tube 202 accesses bias voltage 203 (VBP), and the drain electrode connection current mirror of current source PMOS tube 202 inputs NMOS tube
204 drain electrode, current mirror input the grid of the grid connection current mirror output NMOS tube 205 of NMOS tube 204, current mirror output
The electric discharge node 115 of the drain electrode connection fingerprint sensor acquisition array of NMOS tube 205, provides for collection point output driving pipe 110
The ratio of necessary bias current, the bias current and current mirror input 204 electric current of NMOS tube is equal to current mirror and exports NMOS tube
205 and current mirror input 204 size of NMOS tube ratio；Current mirror inputs NMOS tube 204 and current mirror exports NMOS tube 205
Source electrode ground connection.Bias voltage 203 (VBP) and current source PMOS tube 202 codetermine the size of current of active pull-up circuit 116,
The electric current that current mirror inputs NMOS tube 204 is equal to the size of current of current source PMOS tube 202.
Inventor's analysis finds when selected collection point is in reset state, conventional current source to electric discharge node 115 into
Row electric discharge, since current source can only provide constant current offset, the charge velocity of discharge discharged on node 115 is limited, in this way
The resetting time for just substantially prolonging each collection point reduces the acquisition speed of acquisition array.Therefore to raising fingerprint image
The acquisition speed of picture needs to set about from the charge velocity of discharge improved on electric discharge node 115.
Inventor considers to improve conventional active pull-up circuit, increases auxiliary discharge access on the basis of current source,
To improve the charge velocity of discharge on common node, shorten the resetting time of each collection point.As shown in figure 3, improved active
Load circuit 11600 includes current source and auxiliary discharge access 3000, and auxiliary discharge access 3000 and current source are in parallel, and auxiliary is put
3000 one end of electric pathway connects the electric discharge node 115 of fingerprint sensor acquisition array, other end ground connection, auxiliary discharge access 3000
Repid discharge is carried out to electric discharge node 115 in the case where fingerprint sensor acquires array reset state.
One of common structure of current source includes power supply 201, current source PMOS tube 202 and current mirror 200, current mirror 200
NMOS tube 204 is inputted including current mirror and current mirror exports NMOS tube 205, and the source electrode of current source PMOS tube 202 connects power supply
201, the grid of current source PMOS tube 202 accesses bias voltage 203 (VBP), and the drain electrode of current source PMOS tube 202 connects current mirror
The drain electrode of NMOS tube 204 is inputted, current mirror inputs the grid of the grid connection current mirror output NMOS tube 205 of NMOS tube 204, electricity
The electric discharge node 115 of the drain electrode connection fingerprint sensor acquisition array of mirror output NMOS tube 205 is flowed, current mirror inputs NMOS tube
204 and current mirror output NMOS tube 205 source electrode ground connection.
Further, inventor further investigate to auxiliary discharge access and Method of Spreading Design, auxiliary as shown in Figure 4 are put
A kind of structure of electric pathway is strong discharge path, and improved active pull-up circuit 11601 includes strong electric discharge NMOS tube 300, Qiang Fang
The drain electrode connection of the grid incoming control signal 301 of electric NMOS tube, the source electrode ground connection of Qiang Fang electricity NMOS tube, Qiang Fang electricity NMOS tube is put
Electrical nodes 115.In the case where fingerprint sensor acquires array reset state, the strong discharge path, that is, strong electric discharge NMOS tube are enabled
The control signal of 300 grid becomes high level, controls strong electric discharge NMOS tube 300 and is connected, is in the strong electric discharge NMOS tube 300
Triode region, electric discharge NMOS tube 300 is equivalent to a small resistance by force at this time, quickly leads to the charge of above-mentioned electric discharge node 115
It crosses the strong electric discharge NMOS tube 300 and is quickly released to ground；Before entering fingerprint collecting state (latter half of reset state), close
The strong discharge path is closed, that is, the control signal of the grid of electric discharge NMOS tube 300 becomes low level by force, is exported in current mirror
Under the normal bias of NMOS tube 205, the output driving pipe 110 that fingerprint sensor acquisition array is selected collection point drives parasitic electricity
Hold 118 and be quickly returning to normal bias condition, is ready for the fingerprint collecting state of next stage.
When enabling the strong discharge path, biggish transient current can be generated, which can be to fingerprint sensor
Power supply and ground injection noise.But, biggish transient current will not influence the normal use of fingerprint collecting sensor, only exist
Theoretically existing defect.
The another of auxiliary discharge access as shown in Figure 5 improves structure, and improved active pull-up circuit 11602 includes void
Quasi- collection point (dummy pixel) 406, dummy acquisition point output stage current source NMOS tube 407, operational amplifier 403 and auxiliary
NMOS tube 400, the leakage of dummy acquisition point (dummy pixel) 406 and dummy acquisition point output stage current source NMOS tube 407 is connected
Pole connects and generates reference voltage (VREF) 402, reversed input of the reference voltage (VREF) 402 as operational amplifier 403, fortune
The positive input for calculating amplifier 403 connects electric discharge node, the grid of the output connection auxiliary conducting NMOS tube 400 of operational amplifier 403
Pole, the drain electrode connection electric discharge node of auxiliary conducting NMOS tube 400, the grid of dummy acquisition point output stage current source NMOS tube 407
Connect the grid of current mirror output NMOS tube 205, the source electrode of dummy acquisition point output stage current source NMOS tube 407 and auxiliary conducting
The source electrode of NMOS tube 400 is grounded.
Auxiliary conducting NMOS tube 400 can be N-type MOS transistor, the output control of operational amplifier 403
The on state of auxiliary conducting NMOS tube 400, specifically, operational amplifier 403 calculate the voltage of electric discharge node 115 and with reference to electricity
The difference for pressing (VREF) 402, when difference is greater than 0, the output voltage of operational amplifier 403 increases auxiliary conducting NMOS tube 400
Ducting capacity, enhance to electric discharge node 115 discharge capability；It is gradually become smaller in response to difference, the output of operational amplifier 403
Voltage reduces the ducting capacity of auxiliary conducting NMOS tube 400, weakens the discharge capability to electric discharge node 115, when difference is equal to 0
When, the single collection point 101 in fingerprint collecting array enters normal bias state.
Inventor advanced optimizes the auxiliary discharge access in Fig. 5, obtains the another of auxiliary discharge access as shown in FIG. 6
NMOS tube 400 is connected in current mirror output NMOS tube 205 and auxiliary by a kind of improvement structure, improved active pull-up circuit 11603
Power supply/conducting NMOS tube 501 is merged into, timesharing switching control is carried out using acceleration discharge switch 502, normal bias switch 503.
Specifically, improved active pull-up circuit 11603 includes 406, dummy acquisition dummy acquisition point (dummy pixel)
Point output stage current source NMOS tube 407, operational amplifier 403, acceleration discharge switch 502, normal bias switch 503 and power supply/
NMOS tube 500, the leakage of dummy acquisition point (dummy pixel) 406 and dummy acquisition point output stage current source NMOS tube 407 is connected
Pole connects and generates reference voltage (VREF) 402, reversed input of the reference voltage (VREF) 402 as operational amplifier 403, fortune
The positive input for calculating amplifier 403 connects electric discharge node 115, and the output of operational amplifier 403 connects power supply/conducting NMOS tube 500
Grid, the drain electrode of power supply/conducting NMOS tube 500 connection electric discharge node, dummy acquisition point output stage current source NMOS tube 407
Grid connects power supply/conducting NMOS tube 500 grid, and the source electrode and power supply of dummy acquisition point output stage current source NMOS tube 407/
The source electrode ground connection that NMOS tube 500 is connected, accelerates discharge switch 502 to be set to the output and power supply/conducting of operational amplifier 403
Between the grid of NMOS tube 500, normal bias switch 503 is set to the grid of dummy acquisition point output stage current source NMOS tube 407
Between pole and power supply/conducting NMOS tube 500 grid.
Accelerate discharge switch 502, normal bias switch 503 to carry out timesharing switching control to refer to when fingerprint sensor acquires battle array
When collection point in column selection enters reset state, discharge switch 502 is accelerated to be closed, normal bias switch 503 disconnects, operation amplifier
Device 403 and power supply/conducting NMOS tube 500 form feedback loop, and power supply/conducting NMOS tube 500 serves as auxiliary conducting NMOS tube,
Repid discharge is carried out to electric discharge node 115, the voltage of electric discharge node 115 is made to quickly recover to reference voltage (VREF) 402；Work as institute
When stating the collection point chosen of fingerprint sensor acquisition array and entering fingerprint collecting state, discharge switch 502 is accelerated to disconnect, it is normal partially
The closure of switch 503 is set, power supply/conducting NMOS tube 500 serves as current mirror output NMOS tube, for individually adopting in fingerprint collecting array
Collection point 101 provides constant current biasing.
A kind of preferred structure for the dummy acquisition point (dummy pixel) 406 in Fig. 5 and Fig. 6 includes dummy acquisition
Point ratio enlargement capacitor 607, dummy acquisition point row selection control pipe 611, is virtually adopted at dummy acquisition point internal amplification circuit 608
Collection point column selection control pipe 613, dummy acquisition point output driving pipe 610 and dummy acquisition point source 622, dummy acquisition point ratio
Amplification capacitor 607 and dummy acquisition point internal amplification circuit 608 are connected in parallel, 607 both ends of dummy acquisition point ratio enlargement capacitor
It is short-circuited, dummy acquisition point internal amplification circuit 608 connects the grid of dummy acquisition point output driving pipe 610, described virtually to adopt
The drain electrode of collection point output driving pipe 610 connects the dummy acquisition point source 622, the dummy acquisition point output driving pipe 610
Source electrode connect the drain electrode of dummy acquisition point row selection control pipe 611, the dummy acquisition point row selection control pipe 611
Source electrode connects the drain electrode of the dummy acquisition point column selection control pipe 613, the source of the dummy acquisition point column selection control pipe 613
Pole connects the drain electrode of the dummy acquisition point output stage current source NMOS tube 407, the dummy acquisition point row selection control pipe 611
The dummy acquisition point source 622, the dummy acquisition point are connected with the grid of dummy acquisition point column selection control pipe 613
Row selection control pipe 611 and dummy acquisition point column selection control pipe 613 are in normally on.
Inventor devises a kind of fingerprint sensor 10000, using in any of the above-described embodiment based on fingerprint sensor
The active pull-up circuit of array output stage is acquired, as shown in fig. 7, active pull-up circuit uses improved active pull-up circuit
11601,11602 or 11603 can also be substituted for.
Inventor devises a kind of circuit, uses the fingerprint sensor in above-described embodiment.As shown in figure 8, fingerprint sensing
The connection such as device and micro-control unit (Microcontroller Unit, MCU), realizes fingerprint identification function.Wherein MCU can be replaced
It is changed to the single machine unit or chip calculated with processing function.
The preferred embodiment of the present invention has been described in detail above.It should be appreciated that those skilled in the art without
It needs creative work according to the present invention can conceive and makes many modifications and variations.Therefore, all technologies in the art
Personnel are available by logical analysis, reasoning, or a limited experiment on the basis of existing technology under this invention's idea
Technical solution, all should be within the scope of protection determined by the claims.
Claims (10)
1. a kind of active pull-up circuit based on fingerprint sensor acquisition array output stage, which is characterized in that including current source and
Auxiliary discharge access, the auxiliary discharge access and the current source are in parallel, and auxiliary discharge access one end connects the finger
Line sensor acquires the electric discharge node of array, other end ground connection, and the auxiliary discharge access acquires battle array in the fingerprint sensor
Repid discharge is carried out to the electric discharge node under column reset state.
2. the active pull-up circuit as described in claim 1 based on fingerprint sensor acquisition array output stage, which is characterized in that
The current source includes power supply, current source PMOS tube and current mirror, and the current mirror includes current mirror input NMOS tube and electric current
Mirror exports NMOS tube, and the source electrode of the current source PMOS tube connects the power supply, and the grid access of the current source PMOS tube is inclined
Voltage VBP is set, the drain electrode of the current source PMOS tube connects the drain electrode of the current mirror input NMOS tube, the current mirror input
NMOS tube grid is connected with the grid of current mirror output NMOS tube, described in the drain electrode connection of the current mirror output NMOS tube
Discharge node, the source electrode ground connection of the current mirror input NMOS tube and current mirror output NMOS tube.
3. the active pull-up circuit as claimed in claim 2 based on fingerprint sensor acquisition array output stage, which is characterized in that
The auxiliary discharge access includes strong electric discharge NMOS tube, the grid incoming control signal of the strong electric discharge NMOS tube, described to put by force
The source electrode of electric NMOS tube is grounded, and the drain electrode of the strong electric discharge NMOS tube connects the electric discharge node.
4. the active pull-up circuit as claimed in claim 2 based on fingerprint sensor acquisition array output stage, which is characterized in that
The auxiliary discharge access includes dummy acquisition point (dummy pixel), dummy acquisition point output stage current source NMOS tube, operation
Amplifier and auxiliary conducting NMOS tube, the dummy acquisition point (dummy pixel) and dummy acquisition point output stage electric current
The drain electrode of source NMOS tube connects and generates reference voltage VREF, and the reference voltage VREF is as the reversed of the operational amplifier
Input, the positive input of the operational amplifier connect the electric discharge node, and the output of the operational amplifier connects the auxiliary
The grid of NMOS tube is connected, the drain electrode of the auxiliary conducting NMOS tube connects the electric discharge node, the dummy acquisition point output
The grid of grade current source NMOS tube is connected with the grid of current mirror output NMOS tube, the dummy acquisition point output stage electric current
The source electrode ground connection of the source electrode of source NMOS tube and the auxiliary conducting NMOS tube.
5. the active pull-up circuit as claimed in claim 4 based on fingerprint sensor acquisition array output stage, which is characterized in that
The auxiliary conducting NMOS tube and current mirror output NMOS tube merge into power supply/conducting NMOS tube, the operational amplifier
Output and the power supply/conducting NMOS tube grid between setting accelerate discharge switch, the leakage of the power supply/conducting NMOS tube
Pole connects the electric discharge node, the grid and the power supply/conducting NMOS of the dummy acquisition point output stage current source NMOS tube
The grid of pipe is connected, and the grid and the power supply/conducting NMOS tube of dummy acquisition point output stage current source NMOS tube
Setting normal bias switch between grid, the source electrode of the dummy acquisition point output stage current source NMOS tube and the power supply/lead
The source electrode ground connection of logical NMOS tube.
6. the active pull-up circuit as claimed in claim 5 based on fingerprint sensor acquisition array output stage, which is characterized in that
The acceleration discharge switch and normal bias switch carry out timesharing switching control to the power supply/conducting NMOS tube, work as institute
When stating the collection point chosen of fingerprint sensor acquisition array and entering reset state, the accelerations discharge switch closure, it is described normally
Biased witch disconnects, and the power supply/conducting NMOS tube serves as auxiliary conducting NMOS tube, is quickly put to the electric discharge node
Electricity makes the voltage of the electric discharge node quickly recover to the reference voltage VREF, when fingerprint sensor acquisition array choosing
In collection point when entering fingerprint collecting state, the acceleration discharge switch disconnects, and the normal bias closes the switch, the electricity
Source/conducting NMOS tube serves as current mirror output NMOS tube, acquires the collection point that array is chosen for the fingerprint sensor and provides perseverance
Constant current biasing.
7. the active pull-up circuit based on fingerprint sensor acquisition array output stage as described in claim 4 to 6 is any, special
Sign is, the dummy acquisition point (dummy pixel) includes dummy acquisition point ratio enlargement capacitor, puts inside dummy acquisition point
Big circuit, dummy acquisition point row selection control pipe, dummy acquisition point column selection control pipe, dummy acquisition point output driving pipe and void
Quasi- acquisition point source, the dummy acquisition point ratio enlargement capacitor and dummy acquisition point internal amplification circuit are connected in parallel,
Dummy acquisition point ratio enlargement capacitor both ends are short-circuited, and the dummy acquisition point internal amplification circuit connects the dummy acquisition point
The drain electrode of the grid of output driving pipe, the dummy acquisition point output driving pipe connects the dummy acquisition point source, the void
The source electrode of quasi- collection point output driving pipe connects the drain electrode of the dummy acquisition point row selection control pipe, the dummy acquisition point row
The source electrode of selection control pipe connects the drain electrode of the dummy acquisition point column selection control pipe, the dummy acquisition point column selection control
The source electrode of pipe connects the drain electrode of the dummy acquisition point output stage current source NMOS tube, the dummy acquisition point row selection control pipe
The dummy acquisition point source, the dummy acquisition point row selection are connected with the grid of dummy acquisition point column selection control pipe
Control pipe and dummy acquisition point column selection control pipe are in normally on.
8. the active pull-up circuit based on fingerprint sensor acquisition array output stage as described in claim 4 to 6 is any, special
Sign is that, when the collection point that fingerprint sensor acquisition array is chosen enters reset state, the operational amplifier calculates
The voltage of the electric discharge node and the difference of the reference voltage VREF, when the difference is greater than 0, the operational amplifier
Output voltage increases the ducting capacity of the auxiliary conducting NMOS tube, enhances the discharge capability to the electric discharge node, in response to
The difference gradually becomes smaller, and the output voltage of the operational amplifier reduces the ducting capacity of the auxiliary conducting NMOS tube, subtracts
The weak discharge capability to the electric discharge node, when the difference is equal to 0, the fingerprint sensor acquires the acquisition that array is chosen
Point output driving pipe enters normal bias state.
9. a kind of fingerprint sensor, which is characterized in that acquired including a method as claimed in any one of claims 1-8 based on fingerprint sensor
The active pull-up circuit of array output stage.
10. a kind of circuit, which is characterized in that including fingerprint sensor as claimed in claim 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910338671.1A CN109889189A (en) | 2019-04-25 | 2019-04-25 | A kind of active pull-up circuit based on fingerprint sensor acquisition array output stage |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910338671.1A CN109889189A (en) | 2019-04-25 | 2019-04-25 | A kind of active pull-up circuit based on fingerprint sensor acquisition array output stage |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN109889189A true CN109889189A (en) | 2019-06-14 |
Family
ID=66938402
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910338671.1A Pending CN109889189A (en) | 2019-04-25 | 2019-04-25 | A kind of active pull-up circuit based on fingerprint sensor acquisition array output stage |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109889189A (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102981543A (en) * | 2012-11-19 | 2013-03-20 | 西安三馀半导体有限公司 | Drive circuit of ultralow-power-consumption linear voltage stabilizer |
| CN105391958A (en) * | 2015-11-05 | 2016-03-09 | 南京邮电大学 | Low-power-consumption column-readout-stage circuit in infrared readout integrated circuit |
| CN106056052A (en) * | 2016-03-25 | 2016-10-26 | 深圳市奔凯安全技术股份有限公司 | Fingerprint collection circuit |
| CN106500845A (en) * | 2016-09-19 | 2017-03-15 | 天津大学 | Diode-type infrared sensor array Pixel-level calibration structure |
| US20170223291A1 (en) * | 2016-02-03 | 2017-08-03 | Sony Corporation | Image sensor and electronic device with active reset circuit, and method of operating the same |
| CN107102671A (en) * | 2017-04-28 | 2017-08-29 | 成都华微电子科技有限公司 | Low-power consumption fast transient response low-voltage difference adjustor |
| CN209748512U (en) * | 2019-04-25 | 2019-12-06 | 宁波爱芯微电子有限公司 | Active load circuit based on fingerprint sensor acquisition array output stage |
-
2019
- 2019-04-25 CN CN201910338671.1A patent/CN109889189A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102981543A (en) * | 2012-11-19 | 2013-03-20 | 西安三馀半导体有限公司 | Drive circuit of ultralow-power-consumption linear voltage stabilizer |
| CN105391958A (en) * | 2015-11-05 | 2016-03-09 | 南京邮电大学 | Low-power-consumption column-readout-stage circuit in infrared readout integrated circuit |
| US20170223291A1 (en) * | 2016-02-03 | 2017-08-03 | Sony Corporation | Image sensor and electronic device with active reset circuit, and method of operating the same |
| CN106056052A (en) * | 2016-03-25 | 2016-10-26 | 深圳市奔凯安全技术股份有限公司 | Fingerprint collection circuit |
| CN106500845A (en) * | 2016-09-19 | 2017-03-15 | 天津大学 | Diode-type infrared sensor array Pixel-level calibration structure |
| CN107102671A (en) * | 2017-04-28 | 2017-08-29 | 成都华微电子科技有限公司 | Low-power consumption fast transient response low-voltage difference adjustor |
| CN209748512U (en) * | 2019-04-25 | 2019-12-06 | 宁波爱芯微电子有限公司 | Active load circuit based on fingerprint sensor acquisition array output stage |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP7374242B2 (en) | Dynamic vision sensor architecture | |
| CN108280432B (en) | Fingerprint identification detection circuit, driving method thereof and display device | |
| US9721140B2 (en) | Sensing method of fingerprint sensor and related sensing circuit | |
| CN104198058B (en) | Single-photon avalanche diode is quenched and reading circuit | |
| CN1161624C (en) | Capacitance detection system and method | |
| CN107958243A (en) | Active fingerprint recognition image element circuit, driving method and display panel | |
| US6909462B1 (en) | Photosensor circuit capable of detecting minute light signal in high precision and image sensor utilizing photosensor circuit | |
| CN110008860B (en) | Fingerprint identification framework and touch panel | |
| CN108062540A (en) | fingerprint recognition detection circuit and its driving method, display panel and display device | |
| KR102001631B1 (en) | Electric field-type fingerprint identification apparatus and state control method and prosthesis identification method thereof | |
| US11604092B2 (en) | Data output device | |
| WO2006128315A1 (en) | Photoarray for detecting time-dependent image data | |
| US9940501B2 (en) | Method and system for processing fingerprint sensing signals and fingerprint identification terminal | |
| CN102025263A (en) | Power supply starting detection circuit | |
| US9710690B1 (en) | Fingerprint sensing system with adaptive power control | |
| US11978279B2 (en) | Fingerprint identification circuit, display panel and control method thereof | |
| CN108171192A (en) | Fingerprint recognition detection circuit and its driving method, display device | |
| TWI793750B (en) | Capacitive fingerprint sensing device | |
| CN106575075A (en) | Differential reference signal distribution method and system | |
| CN103412216A (en) | Electrostatic discharge detection circuit and processing system | |
| CN106020533B (en) | A kind of touch-control circuit, its driving method, touch screen and display device | |
| CN109889189A (en) | A kind of active pull-up circuit based on fingerprint sensor acquisition array output stage | |
| CN111027384B (en) | Fingerprint identification detection circuit, detection method and display device | |
| CN209748512U (en) | Active load circuit based on fingerprint sensor acquisition array output stage | |
| WO2021072666A1 (en) | Fingerprint recognition detection circuit and method, and display device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |