CN103118236A - Device and method for compensating dark current of image sensor - Google Patents
Device and method for compensating dark current of image sensor Download PDFInfo
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- CN103118236A CN103118236A CN2013100480521A CN201310048052A CN103118236A CN 103118236 A CN103118236 A CN 103118236A CN 2013100480521 A CN2013100480521 A CN 2013100480521A CN 201310048052 A CN201310048052 A CN 201310048052A CN 103118236 A CN103118236 A CN 103118236A
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Abstract
The invention discloses a device and a method for compensating dark current of an image sensor. The device comprises a photosensitive pixel array, a dark pixel, a variable gain amplifier, an analog to digital converter and a unit gain buffer. The device is of a fully differential variable gain amplifier structure, two related double sampling capacitors are added, appropriate sequential control is used, difference between output voltage, after reset, of the photosensitive pixel and output voltage, after integration, of the photosensitive pixel is transmitted to an input end of the variable gain amplifier, and difference between output voltage, after reset, of the dark pixel and output voltage, after integration, of the dark pixel is transmitted to another input end of the variable gain amplifier. By sampling capacitors, feedback capacitors and appropriate sequential control, difference between photosensitive pixel reset integral signal difference and dark pixel composite integral signal difference is obtained, and the signals output are signals which are compensated by dark current and reflect actual light intensity information.
Description
Technical field
The invention belongs to the cmos image sensor technical field, relate to a kind of imageing sensor dark current compensation device and method.
Background technology
Imageing sensor is the core of hyundai electronics imaging system, comprises video camera, digital camera, photocopier, scanner etc.Imageing sensor is mainly realized based on two kinds of techniques, complementary type Metal-oxide-semicondutor (CMOS) technique and charge-coupled device (CCD) technique.High due to its integrated level, volume is little, the advantage such as low in energy consumption, the cmos image sensor technology has obtained develop rapidly in recent years.Yet, the dark current of cmos image sensor is relatively large, especially when taking than dark scene, need exposure for a long time, the black level that dark current produces can seizing signal very on a large scale, make output signal can not react real intensity signal, simultaneously, due to the very large scope of black level meeting seizing signal, make effective output area of rear class analog to digital converter reduce.
In order to make the real intensity signal of output signal reaction, increase simultaneously effective output area of rear class analog to digital converter, need to carry out dark current compensation.Many patents have proposed multiple dark current compensation method, although circuit structure is different, similar, are all that the mode by close loop negative feedback realizes.This implementation is being carried out before every photograph frame reads, need to first allow the loop stability of dark current compensation, produce a stable black level, and can change the stabilization time of loop with the change in gain of variable gain amplifier, therefore, this dark current compensation method has reduced the frame frequency of transducer.In addition, the implementation of this closed loop needs a high-precision digital to analog converter, and its required precision is generally high some than the analog to digital converter of row reading circuit.
Summary of the invention
The problem that the present invention solves is to provide a kind of imageing sensor dark current compensation device and compensation method, sampling capacitance and feedback capacity and sequential control by variable gain amplifier, sensitization the pixel poor and dark pixel of integrated signal that resets is resetted that integrated signal is poor to be done poorly again, and this output signal is the signal through the real intensity signal of reaction after dark current compensation.
The present invention is achieved through the following technical solutions:
A kind of imageing sensor dark current compensation device comprises light-sensitive image element array, dark pixel, variable gain amplifier, analog to digital converter and unity gain buffer;
Sensitization pixel circuit in the light-sensitive image element array comprises photodiode, transfer tube, reset switch and source follower input pipe; The illumination of varying strength produces the electric charges of different amounts in photodiode, and to be transferred to the FD charge conversion of naming a person for a particular job by transfer tube be voltage signal, and selects switch this signal to be outputed to the positive input terminal of the variable gain amplifier of these row by the row of these row;
The corresponding dark pixel of every row light-sensitive image element array, dark pixel comprises light sensitive diode, dark transfer tube, reset transistor and dark source follower input pipe, its circuit connects corresponding with the sensitization pixel circuit, dark pixel produces the voltage signal of reflection dark current by resetting and exposing, and selects switch this signal to be outputed to the negative input end of the variable gain amplifier of these row by the row of dark source follower input pipe and Ben Lie;
Dark pixel also is connected to the positive input terminal of unity gain buffer by alignment, the output of unity gain buffer is connected to the negative input end of the variable gain amplifier of negative input end own and all row;
The output signal of variable gain amplifier is connected with the input of analog to digital converter, and the positive input terminal of variable gain amplifier and the signal of the negative input end sequencing control by analog to digital converter realizes subtracting each other, and difference is outputed to analog to digital converter quantizes.
In described sensitization pixel circuit, light sensitive diode plus earth, negative pole connects the drain electrode of transfer tube; The grid of transfer tube is by the TX signal controlling, and source electrode connects the grid of source follower pipe; The drain electrode of reset transistor connects power supply, and grid is controlled by reset signal Reset, and source electrode connects the grid of source follower pipe; The drain electrode of source follower pipe connects power supply, and source electrode is the pixel output.
In described dark pixel, light sensitive diode is covered by the metal shadow shield, plus earth, and negative pole connects the drain electrode of dark transfer tube; The grid of dark transfer tube is controlled by signal transmission TX, bulk potential ground connection, and source electrode connects the grid of dark source follower pipe; The drain electrode of reset transistor connects power supply, and grid is controlled by reset signal Reset, and source electrode connects the grid of dark source follower pipe; The drain power of dark source follower pipe, source electrode is dark pixel output; Produce dark current without dark pixel under optical condition, and flowing to dark FD point by dark transfer tube, producing the dark voltage signal of reaction dark current information.
TX signal, Reset signal that TX signal in described dark pixel, Reset signal and one's own profession light-sensitive image element array respond are identical.
Connection between described dark pixel is to be connected by the dark pixel FD point of wire with each dark pixel.
The row of described its respective column of pixel source follower output termination selects the drain terminal of switch; Row selects the source of switch to connect the drain terminal of respective column bias current sources, and grid connects row choosing and the exposure of being expert at and controls decoder;
The row of dark its respective column of pixel source follower output termination selects the drain terminal of switch; Row selects the source electrode of switch to connect the drain terminal of respective column bias current sources, and grid connects row choosing and the exposure of being expert at and controls decoder.
Described variable gain amplifier comprises first relevant two sampling capacitances, second relevant two sampling capacitances, the first reset switch, the second reset switch, the 3rd reset switch, the 4th reset switch, the first sampling capacitance, the second sampling capacitance, the first feedback capacity, the second feedback capacity, and differential operational amplifier;
First relevant two left pole plates of sampling capacitance are the positive input terminal of analog to digital converter, and right pole plate connects the left pole plate of the first sampling capacitance; Second relevant two left pole plates of sampling capacitance are the negative input end of analog to digital converter, and right pole plate connects the left pole plate of the second sampling capacitance;
The first reset switch drain electrode meets the output common mode level Vcm of differential operational amplifier, and source electrode connects the left pole plate of the first sampling capacitance, and grid meets signal S2;
The second reset switch drain electrode meets the output common mode level Vcm of differential operational amplifier, and source electrode connects the left pole plate of the second sampling capacitance, and grid meets signal S2;
The 3rd reset switch drain electrode connects the first positive input terminal of differential operational amplifier, and source electrode connects the second negative output terminal of differential operational amplifier, and grid meets signal S1;
The 4th reset switch drain electrode connects the first negative input end of differential operational amplifier, and source electrode connects differential operational amplifier the second positive output end, and grid meets signal S1;
The right pole plate of the first sampling capacitance connects the first positive input terminal of differential operational amplifier, and the right pole plate of the second sampling capacitance connects the first negative input end of differential operational amplifier;
The left pole plate of the first feedback capacity connects the first positive input terminal of differential operational amplifier, and right pole plate connects the second negative output terminal of differential operational amplifier;
The left pole plate of the second feedback capacity connects the first negative input end of differential operational amplifier, and right pole plate connects the second positive output end of differential operational amplifier.
The appearance value of described first relevant two sampling capacitances, second relevant two sampling capacitances, the first sampling capacitance, the second sampling capacitance all equates;
The first feedback capacity equates with the appearance value of the second feedback capacity.
Compensation method based on described imageing sensor dark current compensation device comprises following operation:
In the rising edge moment that resets for the second time of pixel, will go and select switch conduction, synchronous signal S1 and S2 rise, and make the first reset switch in variable gain amplifier, the second reset switch, the 3rd reset switch, the 4th reset switch conducting;
Before second rising edge of signal TX arrived, control signal S1 turn-offed the first reset switch, the second reset switch, after second rising edge of signal TX arrives, had completed correlated-double-sampling;
At first signal S2 turn-offs the 3rd reset switch, the 4th reset switch afterwards, then first relevant two sampling capacitances, second relevant two right pole plates of sampling capacitance are received V
cm, differential operational amplifier enters amplification mode, voltage difference is amplified, amplification to as if through the information of the reaction light intensity after black level compensation.
Adjust by the ratio that the first sampling capacitance, the first feedback capacity electric capacity are set the multiplication factor that differential operational amplifier needs.
Compared with prior art, the present invention has following useful technique effect:
The dark current compensation device and method that the present invention proposes, can make dark current compensation not affect the transducer frame frequency, do not require simultaneously high-precision analog to digital converter, the method has realized real-time dark current compensation, simultaneously black level is compensated, correlated-double-sampling and variable gain enlarging function are combined closely, and have saved chip area and power consumption, have improved compensation precision.
The dark current compensation device and method that the present invention proposes, adopt the variable gain amplifier structure of fully differential, by increasing by two correlated-double-sampling electric capacity and adopting suitable sequencing control, the difference of output voltage after the rear output voltage of resetting of sensitization pixel and integration is delivered to variable gain amplifier one input, simultaneously the difference of output voltage after the rear output voltage of resetting of dark pixel and integration is delivered to another input of variable gain amplifier.Sampling capacitance and feedback capacity and suitable sequencing control by variable gain amplifier, sensitization the pixel poor and dark pixel of integrated signal that resets is resetted that integrated signal is poor to be done poorly again, and this output signal is the signal through the real intensity signal of reaction after dark current compensation.
Description of drawings
The typical cmos image sensor of Fig. 1;
Fig. 2 sensitization pixel circuit diagram;
The correlated double sampling circuit that Fig. 3 is traditional;
The cmos image sensor that Fig. 4 the present invention proposes;
The dark pixel circuit figure of Fig. 5;
Fig. 6 correlated double sampling circuit level gain-changeable amplifier circuit;
Fig. 7 variable gain amplifier and correlated-double-sampling sequential chart.
Embodiment
The present invention is described in further detail below in conjunction with specific embodiment, and the explanation of the invention is not limited.
Be illustrated in figure 1 as typical cmos image sensor integral layout structure, 10 is the light-sensitive image element array, the light signal of varying strength is converted to the signal of telecommunication of simulation, and select switch 13 to receive on alignment by row, 11 is row reading circuit, the signal of telecommunication of simulation is quantified as is easy to the digital signal storing, transmit.
It is the single pixel circuit of pixel array as Fig. 2, comprise photodiode 101, transfer tube 102, reset switch 103, source follower input pipe 104, the illumination of varying strength produces the electric charge of different amounts in photodiode 101, these electric charges are transferred to FD point 108 by transfer tube 102, be voltage signal with charge conversion, this node voltage signal selects switch 13 to pass on alignment by source follower 104 and row.Alignment is connected to the input of correlated-double-sampling (CDS).
As shown in Figure 3, the CDS circuit signal that resets and expose twice by sampling is delivered to variable gain amplifier (PGA) with difference both and is processed, and passes through Correlated Double Sampling, the fixed pattern noise of pixel circuit can be eliminated, the low-frequency noise of source follower can be suppressed simultaneously.The signal of CDS circuit output is except comprising the exposure signal that reflects intensity signal, also comprise the dark signal that is produced by dark current, when taking the dark scene image, need exposure for a long time, the dark signal of dark current generation is larger with this understanding, make the signal of analog to digital converter (ADC) 16 outputs very large with actual light intensity signal deviation, and dark signal also can occupy the very large output area of ADC.Therefore, in order to make the ADC output signal as much as possible near the actual light intensity signal, and make the output area of ADC maximize, need to carry out dark current compensation.
Traditional dark current compensation mode such as 17 modules in Fig. 1, first gather the dark signal of numeral by loop, dark signal that then should numeral is stored and is passed through digital to analog converter DAC and changes the input that analog signal is delivered to every row PGA into, with CDS output signal and this signal subtraction, obtain reflecting the voltage signal of intensity signal, do again afterwards further processing.Yet this loop is to realize the designer has been proposed many requirements: at first, the required precision of DAC is higher, and figure place is greater than and equals ADC figure place+log
2K, K are the maximum gain of PGA; Secondly, because the gain of PGA can arrange different values under different illumination conditions, therefore can affect the stability of loop, must consider worst case during design, can increase like this settling time of system, affect the transducer frame frequency.
The present invention realizes seamless combination with CDS circuit and PGA circuit, source follow circuit (being formed by device 116 and 114) and the switching tube 115 of traditional C DS circuit have been saved, realized simultaneously the multiplexing of switching tube 112 correlated-double-samplings and PGA enlarging function, reduced chip area, reduced power consumption (power consumption of source follower), the fixed pattern noise of having avoided simultaneously source follower to introduce.
Be illustrated in figure 4 as the visible light image sensor overall structure figure that the present invention proposes.Mainly comprise sensitization pixel 10, decoder 12 is controlled in row choosing and exposure, and row selects switch 13, bias current sources 14, variable gain amplifier 15, analog to digital converter 16, unity gain buffer 18, dark pixel 21.
Sensitization pixel circuit in light-sensitive image element array 10 comprises photodiode 101, transfer tube 102, reset switch 103 and source follower input pipe 104; The illumination of varying strength produces the electric charge of different amounts in photodiode 101, and to be transferred to FD point 108 by transfer tube 102 be voltage signal with charge conversion, and select switch 13 this signal to be outputed to the positive input terminal 300 of the variable gain amplifier 15 of these row by the row of these row;
The corresponding dark pixel 21 of every row light-sensitive image element array 10, dark pixel 21 comprises light sensitive diode 201, dark transfer tube 202, reset transistor 203 and dark source follower input pipe 204, its circuit connects corresponding with the sensitization pixel circuit, dark pixel 21 produces the voltage signal of reflection dark current by resetting and exposing, and selects switch 13 this signal to be outputed to the negative input end 301 of the variable gain amplifier 15 of these row by the row of dark source follower input pipe 204 and Ben Lie;
The output signal of variable gain amplifier 15 is connected with the input of analog to digital converter 16, the positive input terminal 300 of variable gain amplifier 15 and the signal of negative input end 301 sequencing control by analog to digital converter 16 realizes subtracting each other, and difference is outputed to analog to digital converter 16 quantizes.
In described sensitization pixel circuit, light sensitive diode 101 plus earths, negative pole connects the drain electrode of transfer tube 102; The grid of transfer tube 102 is by the TX signal controlling, and source electrode connects the grid of source follower pipe 104; The drain electrode of reset transistor 103 connects power supply, and grid is controlled by reset signal Reset, and source electrode connects the grid of source follower pipe 104; The drain electrode of source follower pipe 104 connects power supply, and source electrode is pixel output 105.
Referring to Fig. 5, in described dark pixel, light sensitive diode 201 is covered by metal shadow shield 109, plus earth, and negative pole connects the drain electrode of dark transfer tube 202; The grid of dark transfer tube 202 is controlled by signal transmission TX, and source electrode connects the grid of dark source follower pipe 204; The drain electrode of reset transistor 203 connects power supply, and grid is controlled by reset signal Reset, and source electrode connects the grid of dark source follower pipe 204; The drain power of dark source follower pipe (204), source electrode is dark pixel output 205; Produce dark current without dark pixel under optical condition, and flowing to dark FD point 208 by dark transfer tube 202, producing the dark voltage signal of reaction dark current information.
TX signal in described dark pixel, Reset signal are identical with TX signal, the Reset signal of 10 responses of one's own profession light-sensitive image element array.Connection between dark pixel is to be connected by the dark pixel FD point 208 of wire with each dark pixel 21.
The row that pixel source follower output 105 connects its respective column selects the drain terminal of switch 13; Row selects the source of switch 13 to connect the drain terminal of respective column bias current sources 14, and grid connects row choosing and the exposure of being expert at and controls decoder 12;
The row that dark pixel source follower output 205 connects its respective column selects the drain terminal of switch 13; Row selects the source electrode of switch 13 to connect the drain terminal of respective column bias current sources 14, and grid connects row choosing and the exposure of being expert at and controls decoder 12.
The effect of unity gain buffer herein is to provide the electric capacity that enough driving forces drive all row PGA inputs.ideally, the positive input of unity gain buffer 18 equates with output, therefore the signal that is connected to all row PGA negative input ends 301 should be the black level signal, in fact, there is offset voltage in buffer 18, make its positive input and output unequal, the signals that cause being connected to all row PGA negative input ends 301 be black level signal and buffer offset voltage and, in order to eliminate the impact of this offset voltage, the input 300 and 301 that positive input terminal and the output of buffer 18 are received respectively these row PGA, after being listed as the amplification of PGA identical gain with other, be converted to digital signal through ADC again, the digital signal of other row ADC output deducts the output signal (by the rear class digital signal processor processes) of the dark row ADC of unit the most at last, obtaining is exactly the signal that reacts real light intensity.
Referring to Fig. 6, described variable gain amplifier 15 comprises first relevant two sampling capacitances 30, second relevant two sampling capacitances 31, the first reset switch 32, the second reset switch 33, the 3rd reset switch 38, the 4th reset switch 39, the first sampling capacitance 34, the second sampling capacitance 35, the first feedback capacity 36, the second feedback capacity 37, and differential operational amplifier 40;
First relevant two left pole plates of sampling capacitance 30 are the positive input terminal 300 of analog to digital converter 16, and right pole plate connects the left pole plate of the first sampling capacitance 34; Second relevant two left pole plates of sampling capacitance 31 are the negative input end 301 of analog to digital converter 16, and right pole plate connects the left pole plate of the second sampling capacitance 35;
The first reset switch 32 drain electrodes meet the output common mode level Vcm of differential operational amplifier 40, and source electrode connects the left pole plate of the first sampling capacitance 34, and grid meets signal S2;
The second reset switch 33 drain electrodes meet the output common mode level Vcm of differential operational amplifier 40, and source electrode connects the left pole plate of the second sampling capacitance 35, and grid meets signal S2;
The 3rd reset switch 38 drain electrodes connect the first positive input terminal 302 of differential operational amplifier 40, and source electrode connects the second negative output terminal 304 of differential operational amplifier 40, and grid meets signal S1;
The 4th reset switch 39 drain electrodes connect the first negative input end 303 of differential operational amplifier 40, and source electrode connects differential operational amplifier 40 second positive output ends 305, and grid meets signal S1;
The right pole plate that the right pole plate of the first sampling capacitance 34 connects the first positive input terminal 302, the second sampling capacitances 35 of differential operational amplifier 40 connects the first negative input end 303 of differential operational amplifier 40;
The left pole plate of the first feedback capacity 36 connects the first positive input terminal 302 of differential operational amplifier 40, and right pole plate connects the second negative output terminal 304 of differential operational amplifier 40;
The left pole plate of the second feedback capacity 37 connects the first negative input end 303 of differential operational amplifier 40, and right pole plate connects the second positive output end 305 of differential operational amplifier 40.
Further, the appearance value of first relevant two sampling capacitances 30, second relevant two sampling capacitances 31, the first sampling capacitance 34, the second sampling capacitance 35 all equates;
The first feedback capacity 36 equates with the appearance value of the second feedback capacity 37.
It is the control sequential chart of pixel and PGA as Fig. 7.In Fig. 7, RESET is the grid control signal of reset transistor 103 in the sensitization pixel, TX is the grid control signal of reset transistor 102 in the sensitization pixel, ROW selects the grid control signal of switch 13 for row, these three sequential are identical with conventional image sensor control sequential, do not repeat them here.S1 and S2 are respectively sampled signal and the amplifying signal of variable gain amplifier 15, when RESET resets the rising edge arrival for the second time, signal S1, S2 raise, make first reset, second reset, the 3rd reset, the 4th reset switch 32,33,38,39 conductings, differential operational amplifier 40 is in the unity gain buffer state, the first sampling capacitance 34, the second sampling capacitance 35 both end voltage are Vcm, electric weight on two electric capacity is 0, the first relevant two sampling capacitances 30 and second relevant two left polar plate voltages of sampling capacitance 31 are respectively V
Active, resetAnd V
Dark, resetWhen the rising edge for the second time of TX arrived, signal S1 descended, and S2 is still high, and the first reset switch 32, the second reset switch 33 disconnect, and this moment first, relevant two sampling capacitances 30 and second relevant two left polar plate voltages of sampling capacitance 31 became V
Active, sigAnd V
Dark, sig, according to the electric charge principle of transfer, this moment, electric capacity 30 and 31 right pole plates became respectively:
In the rising edge moment that resets for the second time of pixel, row selects switch 13 conductings, synchronous signal S1 and S2 rise, make switch first, second, third, fourth reset switch (32,33,38,39) conducting in PGA, differential operational amplifier 40 in PGA is the unit gain negative feedback type, and in PGA, node the first positive input terminal 302, the first negative input end 303 all are stabilized in common mode electrical level V at this moment
cm, due to the first reset switch 32, the second also conducting of reset switch 33, the first sampling capacitance 34 and the second left polar plate voltage of sampling capacitance 35 are also V
cm, therefore the electric charge on the first sampling capacitance 34 and the second sampling capacitance 35 is 0.And this moment first, relevant two right polar plate voltages of sampling capacitance 30 were V
cm, left polar plate voltage is the sensitization pixel rear output end voltage V that resets
Active, reset, so the quantity of electric charge on 30 is:
(V
Active, reset-V
cm) C
30, C
30It is the capacitance of first relevant two sampling capacitances 30;
Second relevant two right polar plate voltages of sampling capacitance 31 are V
cm, left polar plate voltage is the dark pixel rear output end voltage V that resets
Dark, reset, therefore the quantity of electric charge on first relevant two sampling capacitances 30 is:
(V
dark,reset-V
cm)·C
30
Before second rising edge of signal TX arrived, signal S1 turn-offed the first reset switch 32, the second reset switch, and after second rising edge of signal TX arrived, first relevant two sampling capacitance 30 left end voltages became the V after exposure
Active, sig, according to principle of charge conservation, first relevant two sampling capacitance 30 right-hand member voltages are:
First relevant two sampling capacitance 30 left end voltages are V
Dark, sig, second relevant two sampling capacitance 31 right-hand member voltages are:
In fact, completed the correlated-double-sampling function this moment.
At first S2 turn-offs the 3rd reset switch 38, the 4th reset switch 39 afterwards, then first relevant two sampling capacitances 30, second relevant two right pole plates of sampling capacitance 31 are received V
cm, differential operational amplifier 40 enters amplification mode, and amplifier is amplified above-mentioned voltage difference, and the second positive output end 305 that obtains and the voltage difference of the second negative output terminal 304 are:
Can find out, output signal is to (V
Active, reset-V
Active, sig)-(V
Dark, reset-V
Dark, sig) amplified certain multiple, the multiple that specifically needs is selected as required, the multiplication factor that realize to need by the ratio that the first sampling capacitance 34, the first feedback capacity 36 electric capacity are set, and amplify to as if through the information of the real light intensity of reaction after the black level compensation.
Claims (10)
1. an imageing sensor dark current compensation device, is characterized in that, comprises light-sensitive image element array (10), dark pixel (21), variable gain amplifier (15), analog to digital converter (16) and unity gain buffer (18);
Sensitization pixel circuit in light-sensitive image element array (10) comprises photodiode (101), transfer tube (102), reset switch (103) and source follower input pipe (104); The illumination of varying strength produces the electric charge of different amounts in photodiode (101), and to be transferred to FD point (108) by transfer tube (102) be voltage signal with charge conversion, and select switch (13) this signal to be outputed to the positive input terminal (300) of the variable gain amplifier (15) of these row by the row of these row;
The corresponding dark pixel (21) of every row light-sensitive image element array (10), dark pixel (21) comprises light sensitive diode (201), dark transfer tube (202), reset transistor (203) and dark source follower input pipe (204), its circuit connects corresponding with the sensitization pixel circuit, dark pixel (21) produces the voltage signal of reflection dark current by resetting and exposing, and selects switch (13) this signal to be outputed to the negative input end (301) of the variable gain amplifier (15) of these row by the row of dark source follower input pipe (204) and these row;
Dark pixel (21) also is connected to the positive input terminal of unity gain buffer (18) by alignment, the output of unity gain buffer (18) is connected to the negative input end (301) of the variable gain amplifier (15) of negative input end own and all row;
The output signal of variable gain amplifier (15) is connected with the input of analog to digital converter (16), the positive input terminal (300) of variable gain amplifier (15) and the signal of negative input end (301) sequencing control by analog to digital converter (16) realizes subtracting each other, and difference is outputed to analog to digital converter (16) quantizes.
2. imageing sensor dark current compensation device as claimed in claim 1, is characterized in that, in described sensitization pixel circuit, and light sensitive diode (101) plus earth, negative pole connects the drain electrode of transfer tube (102); The grid of transfer tube (102) is by the TX signal controlling, and source electrode connects the grid of source follower pipe (104); The drain electrode of reset transistor (103) connects power supply, and grid is controlled by reset signal Reset, and source electrode connects the grid of source follower pipe (104); The drain electrode of source follower pipe (104) connects power supply, and source electrode is pixel output (105).
3. imageing sensor dark current compensation device as claimed in claim 1, is characterized in that, in described dark pixel, light sensitive diode (201) is covered by metal shadow shield (109), plus earth, and negative pole connects the drain electrode of dark transfer tube (202); The grid of dark transfer tube (202) is controlled by signal transmission TX, and source electrode connects the grid of dark source follower pipe (204); The drain electrode of reset transistor (203) connects power supply, and grid is controlled by reset signal Reset, and source electrode connects the grid of dark source follower pipe (204); The drain power of dark source follower pipe (204), source electrode is dark pixel output (205); Produce dark current without dark pixel under optical condition, and flowing to dark FD point (208) by dark transfer tube (202), producing the dark voltage signal of reaction dark current information.
4. imageing sensor dark current compensation device as claimed in claim 3, is characterized in that, TX signal, Reset signal that TX signal, Reset signal and the one's own profession light-sensitive image element array (10) in dark pixel responds are identical.
5. imageing sensor dark current compensation device as claimed in claim 3, is characterized in that, the connection between dark pixel is to be connected by the dark pixel FD point (208) of wire with each dark pixel (21).
6. imageing sensor dark current compensation device as claimed in claim 3, is characterized in that, the row that pixel source follower output (105) connects its respective column selects the drain terminal of switch (13); Row selects the source of switch (13) to connect the drain terminal of respective column bias current sources (14), and grid connects row choosing and the exposure of being expert at and controls decoder (12);
The row that dark pixel source follower output (205) connects its respective column selects the drain terminal of switch (13); Row selects the source electrode of switch (13) to connect the drain terminal of respective column bias current sources (14), and grid connects row choosing and the exposure of being expert at and controls decoder (12).
7. imageing sensor dark current compensation device as claimed in claim 1, it is characterized in that, described variable gain amplifier (15) comprises first relevant two sampling capacitances (30), second relevant two sampling capacitances (31), the first reset switch (32), the second reset switch (33), the 3rd reset switch (38), the 4th reset switch (39), the first sampling capacitance (34), the second sampling capacitance (35), the first feedback capacity (36), the second feedback capacity (37), and differential operational amplifier (40);
First relevant two left pole plates of sampling capacitance (30) are the positive input terminal (300) of analog to digital converter (16), and right pole plate connects the left pole plate of the first sampling capacitance (34); Second relevant two left pole plates of sampling capacitance (31) are the negative input end (301) of analog to digital converter (16), and right pole plate connects the left pole plate of the second sampling capacitance (35);
The first reset switch (32) drain electrode meets the output common mode level Vcm of differential operational amplifier (40), and source electrode connects the left pole plate of the first sampling capacitance (34), and grid meets signal S2;
The second reset switch (33) drain electrode meets the output common mode level Vcm of differential operational amplifier (40), and source electrode connects the left pole plate of the second sampling capacitance (35), and grid meets signal S2;
The 3rd reset switch (38) drain electrode connects first positive input terminal (302) of differential operational amplifier (40), and source electrode connects second negative output terminal (304) of differential operational amplifier (40), and grid meets signal S1;
The 4th reset switch (39) drain electrode connects first negative input end (303) of differential operational amplifier (40), and source electrode connects differential operational amplifier (40) second positive output ends (305), and grid meets signal S1;
The right pole plate of the first sampling capacitance (34) connects first positive input terminal (302) of differential operational amplifier (40), and the right pole plate of the second sampling capacitance (35) connects first negative input end (303) of differential operational amplifier (40);
The left pole plate of the first feedback capacity (36) connects first positive input terminal (302) of differential operational amplifier (40), and right pole plate connects second negative output terminal (304) of differential operational amplifier (40);
The left pole plate of the second feedback capacity (37) connects first negative input end (303) of differential operational amplifier (40), and right pole plate connects second positive output end (305) of differential operational amplifier (40).
8. imageing sensor dark current compensation device as claimed in claim 7, is characterized in that, the appearance value of first relevant two sampling capacitances (30), second relevant two sampling capacitances (31), the first sampling capacitance (34), the second sampling capacitance (35) all equates;
The first feedback capacity (36) equates with the appearance value of the second feedback capacity (37).
9. the compensation method based on the described imageing sensor dark current compensation of claim 7 device, is characterized in that, comprises following operation:
In the rising edge moment that resets for the second time of pixel, to go and select switch (13) conducting, synchronous signal S1 and S2 rise, and make the first reset switch (32) in variable gain amplifier (15), the second reset switch (33), the 3rd reset switch (38), the 4th reset switch (39) conducting;
Before second rising edge of signal TX arrived, control signal S1 turn-offed the first reset switch (32), the second reset switch (33), after second rising edge of signal TX arrives, had completed correlated-double-sampling;
At first signal S2 turn-offs the 3rd reset switch (38), the 4th reset switch (39) afterwards, then first relevant two sampling capacitances (30), second relevant two right pole plates of sampling capacitance (31) are received V
cm, differential operational amplifier (40) enters amplification mode, voltage difference is amplified, amplification to as if through the information of the reaction light intensity after black level compensation.
10. compensation method as claimed in claim 9, is characterized in that, adjusts by the ratio that the first sampling capacitance (34), the first feedback capacity (36) electric capacity are set the multiplication factor that differential operational amplifier (40) needs.
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| CN201310048052.1A CN103118236B (en) | 2013-02-06 | 2013-02-06 | A kind of dark current of image sensor device and compensation method |
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| CN103759824A (en) * | 2014-01-23 | 2014-04-30 | 西安电子科技大学 | Photoelectric conversion circuit used for visible light sensor |
| CN104394337A (en) * | 2014-12-11 | 2015-03-04 | 昆山锐芯微电子有限公司 | Compensation circuit and control method thereof as well as image sensor circuit |
| CN104427270A (en) * | 2013-08-28 | 2015-03-18 | 北京计算机技术及应用研究所 | Superhigh-definition CMOS image sensor pixel circuit and control method thereof |
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| CN103759824B (en) * | 2014-01-23 | 2016-01-20 | 西安电子科技大学 | For the photoelectric switching circuit of visible light sensor |
| CN103759824A (en) * | 2014-01-23 | 2014-04-30 | 西安电子科技大学 | Photoelectric conversion circuit used for visible light sensor |
| CN105372482A (en) * | 2014-08-19 | 2016-03-02 | 英特希尔美国公司 | System, circuit and method for converting a differential voltage signal including a high common mode voltage component to a ground referenced signal |
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| CN104796634B (en) * | 2015-04-20 | 2018-02-16 | 中国航天科技集团公司第九研究院第七七一研究所 | A kind of pixel biasing circuit and control method for super large face array CMOS image sensor |
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| CN107710626A (en) * | 2015-05-06 | 2018-02-16 | 德克萨斯仪器股份有限公司 | Designed for differential signal and the ADC of common-mode signal |
| CN105306845B (en) * | 2015-11-19 | 2018-04-06 | 电子科技大学 | A kind of correlated double sampling circuit for eliminating imbalance |
| CN105306845A (en) * | 2015-11-19 | 2016-02-03 | 电子科技大学 | Correlated double-sampling circuit capable of cancelling offset |
| CN106534729A (en) * | 2016-11-11 | 2017-03-22 | 中国电子科技集团公司第四十四研究所 | Programmable gain amplifier and method for reducing column fixed mode noise |
| CN106534729B (en) * | 2016-11-11 | 2019-06-11 | 中国电子科技集团公司第四十四研究所 | Programmable gain amplifier and reduction column fixed pattern noise method |
| CN110352593B (en) * | 2016-12-19 | 2021-10-29 | Bae系统成像解决方案有限公司 | Global shutter apparatus for reducing influence of dark current |
| CN110352593A (en) * | 2016-12-19 | 2019-10-18 | Bae系统成像解决方案有限公司 | Reduce the global shutter scheme of the influence of dark current |
| CN107256061B (en) * | 2017-05-25 | 2019-02-12 | 上海集成电路研发中心有限公司 | A kind of infrared image sensor reading circuit |
| CN107256061A (en) * | 2017-05-25 | 2017-10-17 | 上海集成电路研发中心有限公司 | A kind of infrared image sensor reading circuit |
| CN109711391A (en) * | 2019-01-18 | 2019-05-03 | 上海思立微电子科技有限公司 | A kind of image acquisition circuit, acquisition method and terminal device |
| CN111095915A (en) * | 2019-08-29 | 2020-05-01 | 深圳市汇顶科技股份有限公司 | Dark current correlated double sampler, image sensor and dark current compensation method |
| WO2021035605A1 (en) * | 2019-08-29 | 2021-03-04 | 深圳市汇顶科技股份有限公司 | Dark current correlated double sampler, image sensor, and dark current compensation method |
| CN111431532A (en) * | 2020-04-22 | 2020-07-17 | 上海微阱电子科技有限公司 | Wide-output-range high-precision integrator |
| CN111431532B (en) * | 2020-04-22 | 2023-11-07 | 上海微阱电子科技有限公司 | Integrator with wide output range and high precision |
| US20220189043A1 (en) * | 2020-12-15 | 2022-06-16 | Microsoft Technology Licensing, Llc | Correcting line bias in an image |
| US11776138B2 (en) * | 2020-12-15 | 2023-10-03 | Microsoft Technology Licensing, Llc | Correcting line bias in an image |
| CN113271420A (en) * | 2021-06-17 | 2021-08-17 | 中山大学 | Circuit for eliminating fixed pattern noise and image sensor |
| CN114928359A (en) * | 2022-02-11 | 2022-08-19 | 北京大学 | High-precision tracking and holding circuit |
| CN115278096A (en) * | 2022-06-24 | 2022-11-01 | 维沃移动通信有限公司 | Photographing method, photographing apparatus, electronic device, and storage medium |
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