CN209448819U - A kind of pixel circuit with more conversion gains - Google Patents
A kind of pixel circuit with more conversion gains Download PDFInfo
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- CN209448819U CN209448819U CN201920096794.4U CN201920096794U CN209448819U CN 209448819 U CN209448819 U CN 209448819U CN 201920096794 U CN201920096794 U CN 201920096794U CN 209448819 U CN209448819 U CN 209448819U
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Abstract
The utility model provides a kind of pixel circuit with more conversion gains, comprising: voltage source, field-effect tube, charge pass transistor, photodiode, follower and selection transistor；The field-effect tube includes the first field-effect tube and the second field-effect tube, and the charge pass transistor includes the first charge pass transistor and the second transmission transistor, and photodiode includes the first photodiode and the second photodiode；The utility model proposes changing the scheme of charge-voltage switching node capacitor by changing concatenated field-effect tube working condition, thus change conversion gain, extended dynamic range.
Description
Technical field
The utility model belongs to image sensor apparatus field, more particularly, to a kind of pixel electricity with more conversion gains
Road.
Background technique
In Larger Dynamic range imaging scheme, charge-voltage is needed to convert (CG, conversion gain) under low light intensity,
It is worked under high gain mode to improve sensitivity, but due to by charge-voltage switching node (FD, floating
Diffusion) the limitation of output voltage, when conversion gain CG higher, saturated capacity can also be reduced, therefore dynamic range will receive
Limitation.
In existing scheme, multiple exposure Larger Dynamic range technology MEHDR use is more universal, and principle is by repeatedly exposing
The signal of light capture carries out fusion and realizes Larger Dynamic range, but this method Signal to Noise Ratio (SNR) is lower；Another method is,
Two kinds of pixels are used in the same pixel array, one kind having high-gain, and another kind has low gain, then believes different pixels
Number fusion obtains final signal, but this method will cause the redundancy of pixel, while the problems such as can also generate optical homogeneity.
Summary of the invention
In view of this, the utility model is directed to one kind under high-conversion-gain mode, have compared with low noise, it can success
Detect the weak signal under low light intensity；Under low conversion gain mode, full-well capacity with higher can be under the high light intensity of successful probe
Strong signal, be able to achieve the pixel circuit with more conversion gains of Larger Dynamic range.
In order to achieve the above objectives, the technical solution of the utility model is achieved in that
A kind of pixel circuit with more conversion gains, comprising: voltage source, field-effect tube, charge pass transistor, photoelectricity
Diode, follower and selection transistor；The field-effect tube includes the first field-effect tube and the second field-effect tube, the electricity
Lotus transmission transistor includes the first charge pass transistor and the second transmission transistor, and photodiode includes two pole of the first photoelectricity
Pipe and the second photodiode；
One end of the reset transistor is connected with voltage source, and the other end is connected with one end of the second field-effect tube, the
The other end of two field-effect tube is connected with one end of the first field-effect tube, and the other end and charge voltage of the first field-effect tube are converted
Node be connected, the first charge pass transistor, the second charge pass transistor one end respectively with charge voltage switching node phase
Even, the other end of the first charge pass transistor is connected with the first photodiode, and the second charge is published books the other end of transistor
It is connected with the second photodiode, the anode of first photodiode and the second photodiode is grounded respectively.
Further, a follower, the other end of follower and one end of selection transistor are also connected on the voltage source
It is connected；The other end output voltage signal of selection transistor.
Further, the gate terminal of the follower is connected with charge voltage switching node.
Further, the photodiode is photosensitive regions of pixels, for being charge by converting photons.
Further, the drain electrode of first charge pass transistor is connected to charge-voltage switching node, source electrode with
The cathode of first photodiode is connected；The drain electrode of second charge pass transistor is connected to charge-voltage switching node, source
Pole is connected with the cathode of photodiode PD2, and the charge pass transistor is for controlling charge-voltage switching node and photoelectricity
The conducting of diode.
Further, the charge-voltage switching node is for the conversion by signal from charge-domain to voltage domain.
Further, the drain electrode of the follower SF is connected with voltage source, and source electrode is connected with the drain electrode of selection transistor,
Its grid is connected to charge-voltage switching node, and the follower is used to carry out the voltage signal of charge-voltage switching node
Buffering.
Further, the source electrode of second field-effect tube is connected with the drain electrode of the first field-effect tube, the second field-effect tube
Grid for input the second modulated signal；The source electrode of first field-effect tube is connected to charge-voltage conversion node, and first
The grid of effect pipe is for inputting the first modulated signal；Field-effect tube is used for the selection of gain mode.
Further, the source electrode of the reset transistor is connected with the drain electrode of the second effect pipe, drain electrode and voltage source phase
Even, grid is used to input external reset signal, and the reset transistor is used for photodiode and charge-voltage conversion section
The reset of point.
Compared with the existing technology, a kind of pixel circuit with more conversion gains described in the utility model has following excellent
Gesture:
(1) the utility model proposes converted by changing concatenated field-effect tube working condition to change charge-voltage
The scheme of node capacitor, thus change conversion gain, extended dynamic range；
(2) the utility model has lower noise under high-conversion-gain mode, avoids the SNR damage of MEHDR technology
Mistake problem；
(3) the utility model realizes the variation of conversion gain in a pixel, avoids dot structure redundancy；
(4) the utility model in reading by the adjusting to conversion gain, to all have under dim light and intense light conditions compared with
Imaging effect well realizes the imaging of Larger Dynamic range.
Detailed description of the invention
The attached drawing for constituting a part of the utility model is used to provide a further understanding of the present invention, this is practical new
The illustrative embodiments and their description of type are not constituteed improper limits to the present invention for explaining the utility model.?
In attached drawing:
Fig. 1 is structural schematic diagram described in the utility model embodiment.
Specific embodiment
It should be noted that in the absence of conflict, the feature in the embodiments of the present invention and embodiment can
To be combined with each other.
In the description of the present invention, it should be understood that term " first ", " second " etc. are used for description purposes only,
It is not understood to indicate or imply relative importance or implicitly indicates the quantity of indicated technical characteristic.It limits as a result,
There is the feature of " first ", " second " etc. to can explicitly or implicitly include one or more of the features.It is practical new at this
In the description of type, unless otherwise indicated, the meaning of " plurality " is two or more.
In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, term " is pacified
Dress ", " connected ", " connection " shall be understood in a broad sense, for example, it may be being fixedly connected, may be a detachable connection, or integrally
Connection；It can be mechanical connection, be also possible to be electrically connected；Can be directly connected, can also indirectly connected through an intermediary,
It can be the connection inside two elements.For the ordinary skill in the art, on being understood by concrete condition
State the concrete meaning of term in the present invention.
The utility model will be described in detail below with reference to the accompanying drawings and embodiments.
A kind of pixel circuit with more conversion gains, comprising: voltage source, field-effect tube, charge pass transistor, photoelectricity
Diode, follower and selection transistor；The field-effect tube includes the first field-effect tube and the second field-effect tube, the electricity
Lotus transmission transistor includes the first charge pass transistor and the second transmission transistor, and photodiode includes two pole of the first photoelectricity
Pipe and the second photodiode；
One end of the reset transistor is connected with voltage source, and the other end is connected with one end of the second field-effect tube, the
The other end of two field-effect tube is connected with one end of the first field-effect tube, and the other end and charge voltage of the first field-effect tube are converted
Node be connected, the first charge pass transistor, the second charge pass transistor one end respectively with charge voltage switching node phase
Even, the other end of the first charge pass transistor is connected with the first photodiode, and the second charge is published books the other end of transistor
It is connected with the second photodiode, the anode of first photodiode and the second photodiode is grounded respectively.
A follower is also connected on the voltage source, the other end of follower is connected with one end of selection transistor；Selection
The other end output voltage signal of transistor.
The gate terminal of the follower is connected with charge voltage switching node.
The photodiode is photosensitive regions of pixels, for being charge by converting photons.
The drain electrode of first charge pass transistor is connected to charge-voltage switching node, source electrode and the first photoelectricity
The cathode of diode is connected；The drain electrode of second charge pass transistor is connected to charge-voltage switching node, source electrode and photoelectricity
The cathode of diode PD2 is connected, and the charge pass transistor is used to control charge-voltage switching node and photodiode
Conducting.
The charge-voltage switching node is for the conversion by signal from charge-domain to voltage domain.
The drain electrode of the follower SF is connected with voltage source, and source electrode is connected with the drain electrode of selection transistor, and grid connects
It is connected to charge-voltage switching node, the follower is for buffering the voltage signal of charge-voltage switching node.
The source electrode of second field-effect tube is connected with the drain electrode of the first field-effect tube, and the grid of the second field-effect tube is used for
Input the second modulated signal；The source electrode of first field-effect tube is connected to charge-voltage switching node, the grid of the first field-effect tube
For inputting the first modulated signal；Field-effect tube is used for the selection of gain mode.
The source electrode of the reset transistor is connected with the drain electrode of the second effect pipe, and drain electrode is connected with voltage source, and grid is used
Reset signal outside input, the reset transistor is for answering photodiode and charge-voltage conversion node
Position.
The image with large dynamic range sensor pixel circuits of the utility model as shown in Figure 1,
Including reset transistor (RST), two field-effect tube (BIN1, BIN2), two charge pass transistors (TG1,
TG2), two photodiodes (PD1, PD2), follower (SF), selection transistor (SEL) and charge voltage switching node
(FD)；
The first charge pass transistor TG1, the second charge pass transistor TG2 are for controlling charge-voltage conversion
The conducting of node FD and photodiode allow when conducting the light induced electron in photodiode to be transferred to charge-voltage and convert
Node, and in conversion of the charge-voltage switching node FD completion signal from charge-domain to voltage domain；The follower SF will be electric
Lotus-voltage conversion node voltage signal is buffered, the output voltage signal in selection transistor conducting；First effect
Should pipe BIN1, the second field-effect tube BIN2 worked in the off state as capacitor, work under open state as conducting wire；The reset
Transistor RST is for the reset to photodiode and charge-voltage switching node.The grid of selection transistor SEL is connected to
Selection signal sel is exported, source electrode is connected to output end vo ut；
There are three types of operating modes altogether there are three the dot structure of conversion gain for tool provided by the utility model, imitate when first
Should pipe BIN1 and the second field-effect tube BIN2 be low gain mode (LPG) when simultaneously turning on, when the first field-effect tube BIN1 is connected,
Second field-effect tube BIN2 turns off Shi Weizhong gain mode (MPG), as the first field-effect tube BIN1 and the second field-effect tube BIN2
It is when simultaneously turning off high gain mode (HPG)；Cause in photodiode in order to avoid switching between the more gains of reading stage
Charge can not be completely transferred to charge-voltage switching node, the utility model uses 2 photodiodes in one pixel
(PD1, PD2) and 2 charge pass transistors (TG1, TG2), can successively complete electric charge transfer in reading, further increase
Strong ability of regulation and control of this dot structure to conversion gain.
The utility model can increase the field-effect tube number of series connection, realize bigger charge-voltage switching node
The regulating power of capacitor increases the adjustment space of saturated capacity and dynamic range, can also increase in parallel photodiode and
The quantity of charge transfer tube further increases the adjustment space of conversion gain.
The above is only the preferred embodiment of the utility model only, is not intended to limit the utility model, all at this
Within the spirit and principle of utility model, any modification, equivalent replacement, improvement and so on should be included in the utility model
Protection scope within.
Claims (9)
1. a kind of pixel circuit with more conversion gains characterized by comprising voltage source, field-effect tube, charge transmission are brilliant
Body pipe, photodiode, follower and selection transistor；The field-effect tube includes the first field-effect tube and the second field-effect
Pipe, the charge pass transistor include the first charge pass transistor and the second transmission transistor, and photodiode includes the
One photodiode and the second photodiode；
One end of reset transistor is connected with voltage source, and the other end is connected with one end of the second field-effect tube, the second field-effect
The other end of pipe is connected with one end of the first field-effect tube, the other end and the charge voltage switching node phase of the first field-effect tube
Even, the first charge pass transistor, the second charge pass transistor one end be connected respectively with charge voltage switching node, first
The other end of charge pass transistor is connected with the first photodiode, and the second charge is published books the other end and the second light of transistor
Electric diode is connected, and the anode of first photodiode and the second photodiode is grounded respectively.
2. a kind of pixel circuit with more conversion gains according to claim 1, it is characterised in that: on the voltage source
It is also connected with a follower, the other end of follower is connected with one end of selection transistor；The other end of selection transistor exports electricity
Press signal.
3. a kind of pixel circuit with more conversion gains according to claim 2, it is characterised in that: the follower
Gate terminal is connected with charge voltage switching node.
4. a kind of pixel circuit with more conversion gains according to claim 1, it is characterised in that: two pole of photoelectricity
Pipe is photosensitive regions of pixels, for being charge by converting photons.
5. a kind of pixel circuit with more conversion gains according to claim 1, it is characterised in that: first charge
The drain electrode of transmission transistor is connected to charge-voltage switching node, and source electrode is connected with the cathode of the first photodiode；Second
The drain electrode of charge pass transistor is connected to charge-voltage switching node, and source electrode is connected with the cathode of photodiode PD2,
The charge pass transistor is used to control the conducting of charge-voltage switching node and photodiode.
6. a kind of pixel circuit with more conversion gains according to claim 1, it is characterised in that: the charge-electricity
Press switching node for the conversion by signal from charge-domain to voltage domain.
7. a kind of pixel circuit with more conversion gains according to claim 2, it is characterised in that: the follower SF
Drain electrode be connected with voltage source, source electrode is connected with the drain electrode of selection transistor, grid be connected to charge-voltage conversion section
Point, the follower is for buffering the voltage signal of charge-voltage switching node.
8. a kind of pixel circuit with more conversion gains according to claim 1, it is characterised in that: second effect
Should the source electrode of pipe be connected with the drain electrode of the first field-effect tube, the grid of the second field-effect tube is for inputting the second modulated signal；The
The source electrode of one field-effect tube is connected to charge-voltage switching node, and the grid of the first field-effect tube is for inputting the first modulation letter
Number；Field-effect tube is used for the selection of gain mode.
9. a kind of pixel circuit with more conversion gains according to claim 1, it is characterised in that: the reset crystal
The source electrode of pipe is connected with the drain electrode of the second effect pipe, and drain electrode is connected with voltage source, and grid is used to input external reset signal,
The reset transistor is for the reset to photodiode and charge-voltage switching node.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920096794.4U CN209448819U (en) | 2019-01-21 | 2019-01-21 | A kind of pixel circuit with more conversion gains |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920096794.4U CN209448819U (en) | 2019-01-21 | 2019-01-21 | A kind of pixel circuit with more conversion gains |
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| CN209448819U true CN209448819U (en) | 2019-09-27 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114500893A (en) * | 2022-01-26 | 2022-05-13 | 北京京东方光电科技有限公司 | Image sensor, control method thereof and display panel |
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2019
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114500893A (en) * | 2022-01-26 | 2022-05-13 | 北京京东方光电科技有限公司 | Image sensor, control method thereof and display panel |
| CN114500893B (en) * | 2022-01-26 | 2023-07-25 | 北京京东方光电科技有限公司 | Image sensor, control method thereof and display panel |
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