CN108322679A - A kind of circuit and system for eliminating dark current - Google Patents
A kind of circuit and system for eliminating dark current Download PDFInfo
- Publication number
- CN108322679A CN108322679A CN201711470532.1A CN201711470532A CN108322679A CN 108322679 A CN108322679 A CN 108322679A CN 201711470532 A CN201711470532 A CN 201711470532A CN 108322679 A CN108322679 A CN 108322679A
- Authority
- CN
- China
- Prior art keywords
- signal
- dark current
- output
- transistor
- coarse adjustment
- 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.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
- H04N25/60—Noise processing, e.g. detecting, correcting, reducing or removing noise
- H04N25/63—Noise processing, e.g. detecting, correcting, reducing or removing noise applied to dark current
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Transforming Light Signals Into Electric Signals (AREA)
Abstract
The present invention provides a kind of circuits and image sensor system for eliminating dark current, provided with the first sampling capacitance to the 4th sampling capacitance, and two auxiliary capacitance Cb1, Cb2, dark current value is adjusted by coordinating the difference of coarse adjustment converter and thin tuning converter, wherein coarse adjustment converter and thin tuning converter can be the circuit structure of arbitrary framework, coarse adjustment converter realizes coarse adjustment, carefully realizes thin tuning.By the digital value for reading the dark current noise level of dark pixel, and this digital signal value is fed back into coarse adjustment converter and thin tuning converter, when reading valid pixel, due to coarse adjustment converter and thin tuning the calibration noise level of dark current, so that in the reading data of valid pixel and not including dark current noise, to while having effectively eliminated dark current noise, the reduction due to image sensor dynamic range caused by dark current is reduced, the picture quality of imaging sensor is effectively raised.
Description
Technical field
The present invention relates to technical field of integrated circuits, and in particular to a kind of circuit and system for eliminating dark current.
Background technology
In cmos image sensor (CIS), the serious picture quality for affecting imaging sensor of dark current, dark current
Influence to imaging sensor image quality is mainly reflected in two aspects, when, the heterogeneity of dark current is fixed in CIS
One important sources of modal noise so that the permeability of imaging sensor is deteriorated；Second is that dark current can raise entire image
Average value, especially at high temperature, dark current value significantly increase so that the dynamic range of image reduces, although in manufacturing process
On can reduce the intrinsic dark current of photodiode, and improve uniformity, but still need to eliminate when later image is handled or inhibit
Dark current noise is to improve picture quality.
In traditional circuit structure, dark current correction is typically to be carried out in digital end, i.e., counts DARK PIXEL first
The output average value of ARRAY (dark pixel array), each Active Pixel (valid pixel) digital signal subtract Dark
Pixel (dark pixel) digital signal average value, traditional dark current correction can cause the dynamic range of image to reduce, especially exist
Under hot conditions, dark current value increases.
Cmos image sensor general frame figure as shown in Figure 1, Pixel include Dark Pixel (dark pixel) and
Active Pixel (valid pixel), traditional dark current correction subtract the digital signal of each Active Pixel final outputs
The digital signal average value for going Dark Pixel (dark pixel) to export, traditional dark current correction can lead to the dynamic range of image
Reduce.
Cmos image sensor row reading circuit (the Read out circuit) such as Fig. 2 of traditional Column (row) framework
Shown, sequence diagram is as shown in figure 3, its operation principle：When row selects signal SEL is high, selection exports the pixel (pixel) of certain row
Signal value, signal RX are height, and the signal of Vfd nodes is reset to PVDD voltage values, signal by the metal-oxide-semiconductor conducting of signal RX controls
RX is disconnected, and due to channel charge injection effect and clock feedthrough, and node Vfd arrives ground access without any, and node Vfd will be kept about
Less than PVDD voltage values, the reset signal Vrst of output pixel (Pixel), signal RST_COUNT are height, by counter resets,
When first switch S1 is high, comparator resets, Vinp1=Vinm1=Vcm voltages (Vcm is comparator common-mode voltage value),
PIXEL output reset signals Vrst is sampled on sampling capacitance Cs1, and signal TX is opened, and exports the photoreceptor signal of Pixel
The voltage value saltus step of Vsig, Vinp1 are Vcm- (Vrst-Vsig), and when signal EN_COUNT is high, counter starts counting up,
And ramp signal Vramp signals start to change, and Vinm signals follow ramp signal to change, when comparator is overturn, meter
Number device stops counting, and output digit signals D, and the digital signal D of output is the photoreceptor signal value of PIXEL.
Invention content
In order to overcome problem above, the present invention is intended to provide a kind of circuit for eliminating dark current, carries out dark in simulation field
Current correction, to improve the dynamic range of image.
In order to achieve the above object, the present invention provides a kind of circuits for eliminating dark current, including：
The first transistor, grid end connection signal end TX, source are grounded by a diode；
The drain terminal of second transistor, grid end connection signal end RX, source and the first transistor, the grid end of third transistor
It is connected and is connected to node Vfd；Its drain terminal is connected with the drain terminal of third transistor；
Third transistor, source are connect with the drain terminal of the 4th transistor；
4th transistor, grid end connection signal end SEL, source connect and connect jointly with one end of the first sampling capacitance
Ground；
First sampling capacitance, the other end are commonly connected to amplify with one end of the first auxiliary capacitance, one end of first switch
The input terminal of device；
The other end connection thin tuning converter (fine dark) of first auxiliary capacitance；The other end of first switch connects VCM
Signal end；
Second sampling capacitance, one end are connect with ramp generator, one end of the other end and the second auxiliary capacitance, second switch
One end be commonly connected to the input terminal of amplifier；
The other end connection coarse adjustment converter (coarse dark) of second auxiliary capacitance；The other end of second switch connects
VCM signal end；
One end of the first output end connection third sampling capacitance of amplifier, second output terminal connect the 4th sampling capacitance
One end；
The other end of third sampling capacitance is connect jointly with one end that the first input end of a comparator, third switch；
The other end of 4th sampling capacitance is connect jointly with one end of the second input terminal of the comparator, the 4th switch；
First output end of the comparator is connect with the other end that third switchs；
The other end of the second output terminal of the comparator and the 4th switch is commonly connected to the input of a backward dioded
End；
The input terminal of the output end linkage counter of backward dioded；
Counter is connected with EN_COUNT signal ends, RST_COUNT signal ends, and has output signal end.
In one embodiment, the first transistor, second transistor, third transistor, the 4th transistor are identical
The metal-oxide-semiconductor of conduction type.
In one embodiment, the first transistor, second transistor, third transistor, the 4th transistor are NMOS
Pipe.
In one embodiment, the coarse adjustment converter realizes coarse adjustment, and the spoke for quickly adjusting dark current output is bright
Angle value (DN values) can quickly correct dark current noise level；The thin tuning converter realizes thin tuning, the amplitude of thin tuning
Less than the amplitude of coarse adjustment, for keeping the spoke brightness value that dark current exports more accurate.
In order to achieve the above object, the present invention also provides a kind of image sensor systems for eliminating dark current, including：Secretly
Pel array, valid pixel array and the circuit described in claim 1 for eliminating dark current；The electricity for eliminating dark current
Road is connected with dark pixel array, valid pixel array；
Image sensor system counts the signal averaging (Db) of dark pixel array, and output digit signals.
When signal end SEL is high, certain row picture element signal of the circuit output valid pixel array for eliminating dark current
Value；
When signal end RX is high, node Vfd is reset to voltage value by the first transistor conducting of signal end RX controls
PVDD, then signal end RX is disconnected, at this point, node Vfd, without any access to ground, node Vfd will keep being less than about PVDD electricity
Pressure value, if the output reset signal of pixel is Vrst, RST_COUNT signal ends are height, by counter resets；
When the voltage of first switch S1 is high, comparator resets, and the voltage signal Vinp1=second of first input end is defeated
Voltage signal Vinm1=the voltage signals Vcm, Vcm for entering end are the common-mode voltage value of comparator；
The circuit output reset signal Vrst for eliminating dark current is sampled the first sampling capacitance Cs1, and coarse adjustment turns
The initial voltage value of parallel operation and thin tuning converter is sampled on the first auxiliary capacitance Cb1, the second auxiliary capacitance Cb2；
Signal end TX is opened, and exports the photoreceptor signal (Vsig) of valid pixel array, coarse adjustment converter, thin tuning conversion
Device output needs the voltage signal difference (Vdiff) adjusted；Meanwhile the voltage value of the first signal input part of comparator
(Vinp1) saltus step is Vcm- (Vrst-Vsig)-Vdiff；
When signal EN_COUNT signal ends are high, counter starts counting up, and the slope letter that ramp generator is sent out
Number (Vramp) starts to change, and the second input end signal (Vinm) follows ramp signal to change, when comparator is overturn, meter
Number device stops counting, and output digit signals (D), the digital signal (D) of output are the photoreceptor signal value of valid pixel array.
In one embodiment, when image sensor system counts signal averaging (Db) of dark pixel array, number is defeated
It is not 0 to go out, and is changed with the variation of temperature.
In one embodiment, voltage signal interpolation (Vdiff) is calculated by formula Vdiff=(Db*DRAD) ÷ (2*NAD)
Go out；Wherein, DRAD is the amplitude of image sensor system, and NAD is the precision of image sensor system, and Db is dark pixel output
Dark current noise digital signal.
In one embodiment, the coarse adjustment converter realizes coarse adjustment, and the spoke for quickly adjusting dark current output is bright
Angle value (DN values) can quickly correct dark current noise level；The thin tuning converter realizes thin tuning, the amplitude of thin tuning
Less than the amplitude of coarse adjustment, for keeping the spoke brightness value that dark current exports more accurate.
In one embodiment, the step pitch of the thin tuning is image sensor system no more than 1SLB.
In one embodiment, the output voltage range of the coarse adjustment converter and the thin tuning converter is dark electricity
The maximum amplitude value of flow noise.
The circuit of the elimination dark current of the present invention, it is auxiliary to the 4th sampling capacitance and two to be provided with the first sampling capacitance
Capacitance Cb1, Cb2, by coordinate Coarse DAC (coarse adjustment converter) and Fine DAC (thin tuning converter) difference come
Dark current value is adjusted, wherein coarse DAC and Fine DAC can be the circuit structure of arbitrary framework, and Coarse DAC are realized
Coarse adjustment, Fine DAC realize thin tuning.By reading the digital value of the dark current noise level of dark pixel (Dark Pixel),
And this digital signal value is fed back into Coarse DAC and Fine DAC, when reading valid pixel (Active Pixel), by
The noise level of dark current is had recorded in Coarse DAC and Fine DAC, so in the reading data of Active Pixel not
Including dark current noise, to while having effectively eliminated dark current noise, reduce due to image caused by dark current
The reduction of dynamic range of sensor effectively raises the picture quality of imaging sensor, in addition, the imaging sensor of the present invention
The realization of system is simple in structure, is conducive to commercial application.
Description of the drawings
Fig. 1 is the frame diagram of cmos image sensor
Fig. 2 is traditional row reading circuit figure
Fig. 3 is the sequential of the reading circuit of Fig. 2 and the schematic diagram of important node voltage output
Fig. 4 is the row reading circuit figure of the preferred embodiment of the present invention
Fig. 5 is the time diagram of the reading circuit of Fig. 4
Specific implementation mode
To keep present disclosure more clear and easy to understand, below in conjunction with Figure of description, present disclosure is made into one
Walk explanation.Certainly the invention is not limited to the specific embodiment, the general replacement known to those skilled in the art
Cover within the scope of the present invention.
Below in conjunction with attached drawing 4~5 and specific embodiment, invention is further described in detail.It should be noted that attached drawing
Be all made of very simplified form, using non-accurate ratio, and only to it is convenient, clearly reach aid illustration the present embodiment
Purpose.
Referring to Fig. 4, a kind of circuit of elimination dark current of the present embodiment, including：The first transistor, second transistor,
Third transistor, the 4th transistor, the first sampling capacitance Cs1, the second sampling capacitance Cs2, third sampling capacitance Cs3, the 4th adopt
Sample capacitance Cs4, comparator, amplifier, diode, backward dioded, counter, the first auxiliary auxiliary capacitances of capacitance Cb1 and second
Cb2, first switch S1, second switch S2, third switch S3, the 4th switch S4 etc.；Wherein, the first transistor of the present embodiment is extremely
4th transistor is same type of metal-oxide-semiconductor, such as NMOS tube.
Specifically, the grid end connection signal end TX of the first transistor, the source of the first transistor are grounded by diode；The
The grid end connection signal end RX of two-transistor, the grid of the source of second transistor and the drain terminal of the first transistor, third transistor
End, which is connected, is connected to node Vfd；The drain terminal of second transistor is connected with the drain terminal of third transistor；The source of third transistor with
The drain terminal of 4th transistor connects；
The grid end connection signal end SEL of 4th transistor, one end of the source of the 4th transistor and the first sampling capacitance Cs1
It connects and is grounded jointly；The other end of first sampling capacitance Cs1 and one end, one end of first switch S1 of the first auxiliary capacitance are common
It is connected to the input terminal inm of amplifier；The other end connection thin tuning converter (FINE DAC) of first auxiliary capacitance Cb1；First
The other end connection VCM signal end of switch S1；
One end of second sampling capacitance Cs2 is connect with ramp generator, the other end of the second sampling capacitance Cs2 and second auxiliary
One end of capacitance Cb2, one end of second switch S2 are commonly connected to the input terminal inp of amplifier；Second auxiliary capacitance Cb2's is another
End connection coarse adjustment converter (coarse dark)；The other end connection VCM signal end of second switch S2.Here, coarse adjustment turns
Parallel operation realizes coarse adjustment, and the spoke brightness value (DN values) for quickly adjusting dark current output can quickly correct dark current noise
It is horizontal；Thin tuning converter realizes that thin tuning, the amplitude of thin tuning are less than the amplitude of coarse adjustment, the spoke for making dark current export
Brightness value is more accurate.For example, dark current output digital value is Db=100, go out the voltage adjusted is needed to believe according to formula scales
Number interpolation Db*DRAD/2NAD, i.e. Vdiff=(Db*DRAD) ÷ (2*NAD)；Wherein, DRAD is the width of image sensor system
Value, NAD are the precision of image sensor system, and Db is the dark current noise digital signal of dark pixel output.For example, sensor system
System, which is 1V, expires 10 significance bits of width voltage, and the calculated amplitude voltage of this formula is about 97mV, that is, coarse adjustment and fine tuning
The output voltage difference for saving DAC is 97mV, because the voltage amplitude range adjusted is very big, his 1LSB is adjusted such as coarse adjustment DAC
It for 20mV, that is, needs to adjust 4 step dark current and can reach 80mV, his certain 1LSB, which is 40mV, just only needs 2 steps, thin tuning
The amplitude range very little that DAC is adjusted, (sensing system is 1V expires 10 significance bits of width voltage to the voltage value of 1LSB, then 1LSB is just
It is about 1mV for 1/2 10 powers), it needs to adjust 17 steps, need to just adjust 21 steps in total.If all are just needed by thin tuning
97 steps, only coarse adjustment, then point-device voltage value is just not achieved.
One end of first output end outp connection third sampling capacitances Cs3 of amplifier, the second output terminal of amplifier
One end of the 4th sampling capacitance Cs4 of outm connections；The first input end of the other end and a comparator of third sampling capacitance Cs3
Inm, third switch S3 one end connect jointly；The other end of 4th sampling capacitance Cs4 and the second input terminal of the comparator
Inp, the 4th switch S4 one end connect jointly；
First output end of comparator is connect with the other end of third switch S3；The second output terminal of comparator is opened with the 4th
The other end for closing S4 is commonly connected to the input terminal Vcom out of a backward dioded；The output end connection count of backward dioded
The input terminal of device；
Counter is connected with EN_COUNT signal ends, RST_COUNT signal ends, and has output signal end.
Next the image sensor system of the present embodiment is described in detail in conjunction with Fig. 5.Referring to Fig. 5, being this reality
Apply the sequence diagram of the circuit of the above-mentioned elimination resistance in the dark of example.
A kind of image sensor system of the elimination dark current of the present embodiment, including：Dark pixel array, valid pixel battle array
The circuit of the above-mentioned elimination dark current of row and the present embodiment；Eliminate the circuit and dark pixel array, valid pixel battle array of dark current
Row are respectively connected with.
In the present embodiment, image sensor system obtains the signal averaging Db of dark pixel array by statistics, and defeated
Go out digital signal；It should be noted that ideally this digital signal should be 0, but in practice, due to dark current noise
It influences, the output of this digital signal is not 0, and is changed with the variation of temperature.
Here, when signal end SEL is high, certain row pixel of the circuit output valid pixel array for eliminating dark current
Signal value；When signal end RX is high, node Vfd is reset to voltage value PVDD by the first transistor conducting of signal end RX controls,
Then, signal end RX is disconnected, due to channel charge injection effect and clock feedthrough, at this point, node Vfd is without any leading to ground
Holding is less than about PVDD voltage values by road, node Vfd, if the output reset signal of pixel is Vrst, RST_COUNT signal ends are
Height, by counter resets.
When the voltage of first switch S1 is high, comparator resets, and the voltage signal Vinp1=second of first input end is defeated
Voltage signal Vinm1=the voltages Vcm, Vcm for entering end are the common-mode voltage value of comparator.The circuit output for eliminating dark current resets
Signal Vrst is sampled the first sampling capacitance Cs1, and the initial voltage value of coarse adjustment converter and thin tuning converter is sampled
Onto the first auxiliary capacitance Cb1, the second auxiliary capacitance Cb2.Then, signal TX is opened, and exports the photoreceptor signal of valid pixel array
(Vsig), coarse adjustment converter, the output of thin tuning converter need the voltage signal difference (Vdiff) adjusted；Meanwhile comparator
The first signal input part voltage value (Vinp1) saltus step be Vcm- (Vrst-Vsig)-Vdiff.In the present embodiment, voltage letter
Number interpolation (Vdiff) is calculated by formula Db*DRAD/2NAD, that is, Vdiff=(Db*DRAD) ÷ (2*NAD)；Wherein, DRAD
For the amplitude of image sensor system, NAD is the precision of image sensor system, and Db is the dark current noise number of dark pixel output
Word signal.Here, coarse adjustment converter realizes that thin tuning is realized in coarse adjustment, thin tuning converter；The step pitch of thin tuning is image
Sensing system is not more than 1SLB, and the step pitch of thin tuning is 1 or 0.5LSB of image sensor system.Coarse adjustment converter and
The output voltage range of thin tuning converter is the maximum amplitude value of dark current noise.
When signal EN_COUNT signal ends are high, counter starts counting up, and the slope letter that ramp generator is sent out
Number (Vramp) starts to change, and the second input end signal (Vinm) follows ramp signal to change, when comparator is overturn, meter
Number device stops counting, and output digit signals (D), the digital signal (D) of output are the photoreceptor signal value of valid pixel array.
In conclusion the signal of valid pixel output is adjusted by the calculating of coarse adjustment converter and thin tuning converter
Through subtracting dark current noise in analog domain, it is not 0 phenomenon to be exported caused by correct dark current noise, to realization pair
The method that the dark current noise level of imaging sensor carries out real time correction is realized simple in structure and is easy to implement, reduces
Due to the reduction of image sensor dynamic range caused by dark current, the picture quality of imaging sensor is effectively raised.
Although the present invention is disclosed as above with preferred embodiment, right embodiment is illustrated only for the purposes of explanation, and
It is non-to limit the present invention, those skilled in the art can make without departing from the spirit and scope of the present invention it is several more
Dynamic and retouching, the protection domain that the present invention is advocated should be subject to claims.
Claims (10)
1. a kind of circuit for eliminating dark current, which is characterized in that including：
The first transistor, grid end connection signal (TX), source are grounded by a diode；
Second transistor, grid end connection signal (RX), source are connected with the grid end of the drain terminal of the first transistor, third transistor
It is connected to node (Vfd)；Its drain terminal is connected with the drain terminal of third transistor；
Third transistor, source are connect with the drain terminal of the 4th transistor；
4th transistor, grid end connection signal (SEL), source connect and are grounded jointly with one end of the first sampling capacitance；
One end of first sampling capacitance, the other end and the first auxiliary capacitance, one end of first switch are commonly connected to amplifier
Input terminal；
The other end connection thin tuning converter (FINE DAC) of first auxiliary capacitance；Other end connection (VCM) letter of first switch
Number end；
Second sampling capacitance, one end are connect with ramp generator, one end of the other end and the second auxiliary capacitance, the one of second switch
End is commonly connected to the input terminal of amplifier；
The other end connection coarse adjustment converter (COARSE DAC) of second auxiliary capacitance；The other end connection (VCM) of second switch
Signal end；
One end of the first output end connection third sampling capacitance of amplifier, second output terminal connect the one of the 4th sampling capacitance
End；
The other end of third sampling capacitance is connect jointly with one end that the first input end of a comparator, third switch；
The other end of 4th sampling capacitance is connect jointly with one end of the second input terminal of the comparator, the 4th switch；
First output end of the comparator is connect with the other end that third switchs；
The other end of the second output terminal of the comparator and the 4th switch is commonly connected to the input terminal of a backward dioded；
The input terminal of the output end linkage counter of backward dioded；
Counter is connected with EN_COUNT signal ends, RST_COUNT signal ends, and has output signal end.
2. the circuit according to claim 1 for eliminating dark current, which is characterized in that the first transistor, the second crystal
Pipe, third transistor, the 4th transistor are the metal-oxide-semiconductor of same conductivity type.
3. the circuit according to claim 2 for eliminating dark current, which is characterized in that the first transistor, the second crystal
Pipe, third transistor, the 4th transistor are NMOS tube.
4. the circuit according to claim 1 for eliminating dark current, which is characterized in that the coarse adjustment converter realizes coarse adjustment
Section, the spoke brightness value (DN values) for quickly adjusting dark current output can quickly correct dark current noise level；The fine tuning
It saves converter and realizes that thin tuning, the amplitude of thin tuning are less than the amplitude of coarse adjustment, for making the spoke brightness value of dark current output more
Add accurate.
5. a kind of image sensor system for eliminating dark current, which is characterized in that including：Dark pixel array, valid pixel array,
And the circuit described in claim 1 for eliminating dark current；The circuit for eliminating dark current and dark pixel array, valid pixel
Array is connected；
Image sensor system counts the signal averaging (Db) of dark pixel array, and output digit signals；
When signal end (SEL) is high, certain row pixel signal values of the circuit output valid pixel array for eliminating dark current；
When signal end (RX) is high, node Vfd is reset to voltage value by the first transistor conducting of signal end (RX) control
(PVDD), then signal end (RX) disconnects, at this point, node Vfd, without any access to ground, node (Vfd) will keep below electricity
Pressure value (PVDD), if the output reset signal of pixel is Vrst, RST_COUNT signal ends are height, by counter resets；
When the voltage of first switch (S1) is high, comparator resets, and the voltage signal (Vinp1)=second of first input end is defeated
Voltage signal (the Vinm1)=voltage signal Vcm, Vcm for entering end is the common-mode voltage value of comparator；
The circuit output reset signal (Vrst) for eliminating dark current is sampled the first sampling capacitance (Cs1), and coarse adjustment turns
The initial voltage value of parallel operation and thin tuning converter is sampled the first auxiliary capacitance (Cb1), on the second auxiliary capacitance (Cb2)；
Signal end (TX) is opened, and the photoreceptor signal (Vsig) of valid pixel array, coarse adjustment converter, thin tuning converter are exported
Output needs the voltage signal difference (Vdiff) adjusted；Meanwhile the voltage value (Vinp1) of the first signal input part of comparator
Saltus step is Vcm- (Vrst-Vsig)-Vdiff；
When EN_COUNT signal ends are high, counter starts counting up, and the ramp signal (Vramp) that ramp generator is sent out
Start to change, the second input end signal (Vinm) follows ramp signal to change, and when comparator is overturn, counter stops meter
Number, and output digit signals (D), the digital signal (D) of output are the photoreceptor signal value of valid pixel array.
6. the image sensor system according to claim 5 for eliminating dark current, which is characterized in that in imaging sensor system
Completely when signal averaging (Db) of meter dark pixel array, numeral output is not 0, and is changed with the variation of temperature.
7. the image sensor system according to claim 5 for eliminating dark current, which is characterized in that voltage signal interpolation
(Vdiff) it is calculated by formula Vdiff=(Db*DRAD) ÷ (2*NAD)；Wherein, DRAD is the width of image sensor system
Value, NAD are the precision of image sensor system, and Db is the dark current noise digital signal of dark pixel output.
8. the image sensor system according to claim 5 for eliminating dark current, which is characterized in that the coarse adjustment conversion
Device realizes coarse adjustment, and the spoke brightness value (DN values) for quickly adjusting dark current output can quickly correct dark current noise water
It is flat；The thin tuning converter realizes thin tuning, and the amplitude of thin tuning is less than the amplitude of coarse adjustment, for making dark current export
Spoke brightness value is more accurate.
9. the image sensor system according to claim 8 for eliminating dark current, which is characterized in that the step of the thin tuning
Away from be image sensor system be not more than 1LSB.
10. the image sensor system according to claim 8 for eliminating dark current, which is characterized in that the coarse adjustment turns
The output voltage range of parallel operation and the thin tuning converter is the maximum amplitude value of dark current noise.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711470532.1A CN108322679B (en) | 2017-12-29 | 2017-12-29 | Circuit and system for eliminating dark current |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711470532.1A CN108322679B (en) | 2017-12-29 | 2017-12-29 | Circuit and system for eliminating dark current |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108322679A true CN108322679A (en) | 2018-07-24 |
| CN108322679B CN108322679B (en) | 2020-06-30 |
Family
ID=62894025
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201711470532.1A Active CN108322679B (en) | 2017-12-29 | 2017-12-29 | Circuit and system for eliminating dark current |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108322679B (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109495700A (en) * | 2018-10-30 | 2019-03-19 | 成都微光集电科技有限公司 | A kind of circuit and its system of the elimination dark current using novel inclined generator |
| CN110245649A (en) * | 2019-07-31 | 2019-09-17 | 上海天马微电子有限公司 | Display panel, driving method and display device |
| CN110545388A (en) * | 2019-08-28 | 2019-12-06 | 上海集成电路研发中心有限公司 | Device and method for removing image dark current |
| CN110784668A (en) * | 2019-10-28 | 2020-02-11 | 成都微光集电科技有限公司 | Image sensor reading circuit and method for correcting dark current |
| CN111432093A (en) * | 2020-03-19 | 2020-07-17 | 成都微光集电科技有限公司 | Dark current correction method of CMOS image sensor |
| CN113473047A (en) * | 2020-03-31 | 2021-10-01 | 比亚迪半导体股份有限公司 | Noise cancellation method and apparatus, medium, device, and image sensor |
| CN114025110A (en) * | 2021-11-03 | 2022-02-08 | 成都微光集电科技有限公司 | Pixel unit array circuit |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114979513A (en) | 2022-05-19 | 2022-08-30 | 成都微光集电科技有限公司 | Method and system for reducing column noise of image sensor |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5371763A (en) * | 1992-11-13 | 1994-12-06 | At&T Corp. | Packet mode digital data receiver |
| CN1691747A (en) * | 2004-04-23 | 2005-11-02 | 索尼株式会社 | Optical black level control circuits |
| WO2016106478A1 (en) * | 2014-12-29 | 2016-07-07 | 中国科学院半导体研究所 | Analogue readout pre-processing circuit for cmos image sensor and control method therefor |
-
2017
- 2017-12-29 CN CN201711470532.1A patent/CN108322679B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5371763A (en) * | 1992-11-13 | 1994-12-06 | At&T Corp. | Packet mode digital data receiver |
| CN1691747A (en) * | 2004-04-23 | 2005-11-02 | 索尼株式会社 | Optical black level control circuits |
| CN100377569C (en) * | 2004-04-23 | 2008-03-26 | 索尼株式会社 | Optical black level control circuits |
| WO2016106478A1 (en) * | 2014-12-29 | 2016-07-07 | 中国科学院半导体研究所 | Analogue readout pre-processing circuit for cmos image sensor and control method therefor |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109495700A (en) * | 2018-10-30 | 2019-03-19 | 成都微光集电科技有限公司 | A kind of circuit and its system of the elimination dark current using novel inclined generator |
| CN110245649A (en) * | 2019-07-31 | 2019-09-17 | 上海天马微电子有限公司 | Display panel, driving method and display device |
| CN110545388A (en) * | 2019-08-28 | 2019-12-06 | 上海集成电路研发中心有限公司 | Device and method for removing image dark current |
| CN110545388B (en) * | 2019-08-28 | 2022-04-01 | 上海集成电路研发中心有限公司 | Device and method for removing image dark current |
| CN110784668A (en) * | 2019-10-28 | 2020-02-11 | 成都微光集电科技有限公司 | Image sensor reading circuit and method for correcting dark current |
| CN110784668B (en) * | 2019-10-28 | 2021-06-15 | 成都微光集电科技有限公司 | Image sensor reading circuit and method for correcting dark current |
| CN111432093A (en) * | 2020-03-19 | 2020-07-17 | 成都微光集电科技有限公司 | Dark current correction method of CMOS image sensor |
| CN113473047A (en) * | 2020-03-31 | 2021-10-01 | 比亚迪半导体股份有限公司 | Noise cancellation method and apparatus, medium, device, and image sensor |
| CN113473047B (en) * | 2020-03-31 | 2024-09-17 | 比亚迪半导体股份有限公司 | Noise elimination method and device, medium, device and image sensor |
| CN114025110A (en) * | 2021-11-03 | 2022-02-08 | 成都微光集电科技有限公司 | Pixel unit array circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108322679B (en) | 2020-06-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108322679A (en) | A kind of circuit and system for eliminating dark current | |
| CN109495700A (en) | A kind of circuit and its system of the elimination dark current using novel inclined generator | |
| EP0986900B1 (en) | Dc offset and gain correction for cmos image sensor | |
| CN104363020B (en) | A kind of production line analog-digital converter and its error calibrating method | |
| KR102324713B1 (en) | Ramp signal generator and image sensor | |
| EP0986898B1 (en) | Cmos image sensor with improved fill factor | |
| CN101803368A (en) | Current/voltage mode image sensor with switchless active pixels | |
| CN104617930A (en) | Comparator and analog-digital converting apparatus using the same | |
| WO1998056168A1 (en) | Cmos image sensor with reduced fixed pattern noise | |
| CN103379297A (en) | Imaging apparatus and imaging system | |
| GB2482278A (en) | Image sensor analogue to digital conversion (ADC) with ramp signal delay compensation | |
| US20060038208A1 (en) | Apparatus and method of image processing to avoid image saturation | |
| CN104677501A (en) | Uncooled infrared focal plane array heterogeneity correcting method and device | |
| CN111385496A (en) | Ramp signal generator and image sensor including the same | |
| CN104363019B (en) | A kind of production line analog-digital converter and its capacitor mismatch error calibration method | |
| CN109361883B (en) | Pixel readout circuit and image sensor | |
| CN101557462A (en) | Efficient wide-range and high-resolution black level and offset calibration system | |
| CN111399585B (en) | Dark current eliminating circuit using novel slope generator and system thereof | |
| CN111193881B (en) | Comparator with low stripe noise | |
| CN103220476B (en) | Image processing apparatus and method | |
| US7242429B1 (en) | Method for cancellation of the effect of charge feedthrough on CMOS pixel output | |
| CN101873413A (en) | Black level correction circuit and solid-state imaging apparatus | |
| CN112752044B (en) | Ramp generator, pixel column readout circuit and image sensor | |
| CN115002368A (en) | Method and device for correcting oblique wave signal, processing device and image sensor | |
| CN114071039B (en) | Correction circuit, pixel unit readout circuit and CMOS image sensor |
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 | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |