Photoelectric conversion device, driving method of the photoelectric conversion device, and device

Abstract

To enable an output of a high-quality signal.SOLUTION: A driving method of a photoelectric conversion device, comprises: a pixel having a photoelectric conversion element that generates an electric charge in accordance with an incident light, and a transfer transistor that transfers an electric charge to a floating diffusion region; an output line that can be electrically connected to the pixel and outputs a pixel signal on the basis of the electric charge; and a current source that can be electrically connected to the output line and supplies the current to the output line. At a first timing, the electric charge is transferred to the floating diffusion region so that the transfer transistor becomes an ON state. At a second timing, a comparison between a pixel signal based on the electric charge transferred to the floating diffusion region at the first timing and a threshold value voltage is completed. In a timing between the first and second timings, a first driving for changing a connection state of the pixel and the current source from a conductive state to a non-conductive state is performed.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a photoelectric conversion device, a driving method of the photoelectric conversion device, and an apparatus.

Background Art

[0002] Patent Document 1 discloses a technique of determining a voltage value (signal amplitude value) of a pixel signal output from a pixel and performing AD conversion by switching an AD conversion gain according to the voltage value (signal amplitude value) of the pixel signal.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the photoelectric conversion device as shown in Patent Document 1, there is room for improvement in improving the determination accuracy of the voltage value (signal amplitude value) of the pixel signal. By improving the determination accuracy of the voltage value (signal amplitude value) of the pixel signal, the photoelectric conversion device can output a high-quality signal.

[0005] An object of the present invention is to provide a driving method of a photoelectric conversion device capable of outputting a high-quality signal.

Means for Solving the Problems

[0006] According to one disclosure of this specification, a pixel having a photoelectric conversion element that generates charges in response to incident light, a floating diffusion region, and a transfer transistor that transfers the charges to the floating diffusion region, an output line that is electrically connectable to the pixel and outputs a pixel signal based on the charges, and a current source that is electrically connectable to the output line and supplies a current to the output line, and a driving method of the photoelectric conversion device includes, at a first timing, turning on the transfer transistor to transfer the charges to the floating diffusion region, at a second timing, completing a comparison between the pixel signal based on the charges transferred to the floating diffusion region at the first timing and a threshold voltage, and performing a first driving to change a connection state between the pixel and the current source from a conductive state to a non-conductive state between the first timing and the second timing. A driving method of a photoelectric conversion device is provided.

Advantages of the Invention

[0007] According to the present invention, it is possible to output a high-quality signal.

Brief Description of the Drawings

[0008]

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Modes for Carrying Out the Invention

[0009] Hereinafter, each embodiment will be described with reference to the drawings. Note that the following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiments, not all of these plurality of features are essential to the invention, and the plurality of features may be arbitrarily combined. Further, in the accompanying drawings, the same or similar configurations are given the same reference numerals, and redundant descriptions are omitted. In each of the embodiments described below, as an example of the photoelectric conversion device, a sensor for imaging will be mainly described. However, each embodiment is not limited to the sensor for imaging, and is also applicable to other examples of the photoelectric conversion device. For example, there are an imaging device, a distance measuring device (a device for distance measurement using focus detection or TOF (Time Of Flight)), a photometric device (a device for measuring the amount of incident light), and the like.

[0010] In this specification, terms indicating specific directions and positions (for example, "up", "down", "right", "left", and other terms including those terms) are used as necessary. The use of those terms is for facilitating the understanding of the embodiments with reference to the drawings, and the technical scope of the present invention is not limited by the meanings of those terms.

[0011] In this specification, when it is described that "member A and member B are electrically connected", it is not limited to the case where member A and member B are directly connected. For example, even if another member C is connected between member A and member B, it is sufficient that they are electrically connected.

[0012] <First Embodiment> The photoelectric conversion device according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 5.

[0013] FIG. 1 is an example of a block diagram of the photoelectric conversion device according to the present embodiment.

[0014] As shown in FIG. 1, the photoelectric conversion device includes a pixel array unit 110, a vertical scanning circuit 120, an output line 130, a current source 135, a signal processing unit 140, and a reference signal output circuit 150. Further, the photoelectric conversion device includes a counter circuit 310, a horizontal scanning circuit 320, an output circuit 330, and a control circuit 340.

[0015] In the pixel array unit 110, a plurality of pixels 100 are arranged in a matrix over a plurality of rows and a plurality of columns. Further, the output line 130 and the signal processing unit 140 are arranged corresponding to each column in which the pixels 100 are arranged. The pixel 100 includes a photoelectric conversion element that generates charges by photoelectric conversion, converts the charges generated by the photoelectric conversion element into a voltage signal, and outputs the voltage signal to the output line 130. That is, the pixel 100 generates a pixel signal based on the charges, and the generated pixel signal is output to the output line 130 that can be electrically connected to the pixel 100. In FIG. 1, the output line 130 is an output line connected to a plurality of pixels 100 arranged in the vertical direction, but may be an output line connected to a plurality of pixels 100 arranged in the horizontal direction, for example. Further, the current source 135 can be electrically connected to the output line 130 and supplies current to the output line 130.

[0016] The signal processing unit 140 includes a comparator 160, a switching unit 170, a selection unit 200, and a memory unit 250. The switching unit 170 includes a switch 180 and a switch 190. The pixel signal output from the pixel 100 is input to one input terminal of the comparator 160 included in the corresponding signal processing unit 140 via the corresponding output line 130. Further, the reference signal output circuit 150 outputs a ramp signal VRAMP, which is a signal whose voltage changes with the passage of time. The output ramp signal VRAMP is input to the other input terminal of the comparator 160 via the switching unit 170. The signal processing unit 140 performs AD (analog-digital) conversion on the pixel signal, which is an analog signal, using the ramp signal VRAMP and outputs a digital signal.

[0017] Note that the reference signal output circuit 150 may generate the ramp signal VRAMP, or a circuit different from the reference signal output circuit 150 may generate the ramp signal VRAMP. In this embodiment, a ramp signal VRAMP having a constant slope (voltage change amount per unit time) is used, but a ramp signal VRAMP whose slope changes midway may also be used. The ramp signal VRAMP whose slope changes midway includes, for example, the case where it changes in a stepwise manner. The reference signal output circuit 150 can output a plurality of ramp signals VRAMP having different slopes. In this embodiment, the reference signal output circuit 150 outputs a ramp signal VRAMP_L (first reference signal) having a small slope and a ramp signal VRAMP_H (second reference signal) having a large slope.

[0018] The memory unit 250 includes a pulse generator 260, a selector circuit 265, a first memory circuit 270, a second memory circuit 280, a third memory circuit 290, and a selector circuit 300.

[0019] The selection unit 200 includes a fourth memory circuit 210, a NAND gate circuit 220, a NAND gate circuit 230, and an INV gate circuit 240. The selection unit 200 selects any one of the plurality of reference signals.

[0020] Comparator 160 outputs a comparison result signal indicating the result of comparing the pixel signal input via output line 130 with the reference signal to memory unit 250 and the fourth memory circuit 210. Specifically, comparator 160 outputs a high level when the voltage of the reference signal is higher than the voltage of the pixel signal (when the signal amplitude of the reference signal is smaller than that of the pixel signal). Comparator 160 outputs a low level when the voltage of the reference signal is lower than the voltage of the pixel signal (when the signal amplitude of the reference signal is larger than that of the pixel signal). This signal amplitude means the voltage of the difference with respect to the reference voltage serving as a reference. This reference voltage can be considered here as the voltage of the reset level signal (described later) output by pixel 100. Also, from another perspective, it can be considered as the power supply voltage supplied to the amplification transistor 430 (described later) of pixel 100. Note that the relationship between the high level and the low level at this time is an example, and the reverse relationship may also be possible. Memory unit 250 and the fourth memory circuit 210 hold the count signal CNT output from counter circuit 310 (described later) based on the change in the signal level of the comparison result signal output from comparator 160. As an example, based on the change in the signal level of the comparison result signal output from comparator 160, pulse generator 260 generates a short-duration one-shot pulse. Then, selector circuit 265 supplies the pulse to the first memory circuit 270, the second memory circuit 280, and the third memory circuit 290. As a result, the first memory circuit 270, the second memory circuit 280, and the third memory circuit 29 hold the count signal CNT of the signal value corresponding to the value of the pixel signal as a digital signal corresponding to the pixel signal, and the pixel signal output from pixel 100 is AD-converted.

[0021] The first memory circuit 270 and the second memory circuit 280 hold a digital signal obtained by AD-converting the reset level signal (hereinafter, N signal) of the floating diffusion section 420 described later. Note that this digital signal also includes components of the characteristic variations for each signal processing unit 140. The third memory circuit 290 holds a digital signal obtained by AD-converting a signal (hereinafter, S signal) in which the signal (photoelectric conversion signal) of the photoelectric conversion element 400 described later is superimposed on the N signal of the FD section 420.

[0022] In the fourth memory circuit 210, the result of comparing and determining the threshold voltage (first reference signal) output by the reference signal output circuit 150 with the pixel signal by the comparator 160 is held. In the present embodiment, the reference signal output circuit 150 outputs a constant signal whose voltage does not change with time when outputting the threshold voltage, but may output a signal whose voltage changes with time as the threshold voltage. Note that a circuit provided separately from the reference signal output circuit 150 may generate or output the above-described constant signal whose voltage does not change.

[0023] The counter circuit 310 outputs a count signal CNT used for AD conversion performed by the signal processing unit 140. The count signal CNT is a signal that counts the clock pulse signal CLK supplied from a clock pulse supply circuit (not shown) from the time when the reference signal of the reference signal output circuit 150 starts to change depending on time. That is, the counter circuit 310 counts the clock pulse signal CLK in parallel with the change in the voltage of the reference signal, and generates and outputs the count signal CNT. Note that the counter circuit 310 shown in FIG. 1 is provided in common for each signal processing unit 140, but may be provided corresponding to each of the signal processing units 140.

[0024] The horizontal scanning circuit 320 selects the memory unit 250. The signal held in the selected memory unit 250 is sequentially transferred to the output circuit 330 by the horizontal scanning signal output from the horizontal scanning circuit 320. The output circuit 330 performs correction processing on the obtained signal, and outputs the signal subjected to the correction processing to the outside of the photoelectric conversion device. For example, in the output circuit 330, the digitized N signal is subtracted from the digitized S signal, and a signal with reduced noise components is output. The vertical scanning circuit 120 sequentially performs an operation of selecting a predetermined row. The control circuit 340 supplies drive signals to the vertical scanning circuit 120, the signal processing unit 140, the reference signal output circuit 150, the counter circuit 310, and the horizontal scanning circuit 320. Further, the control circuit 340 outputs a control signal s1, a control signal s2, and a control signal s3 to the selection unit 200.

[0025] FIG. 2 is an example of a circuit diagram of pixel 100 included in the photoelectric conversion device according to the present embodiment.

[0026] As shown in FIG. 2, pixel 100 includes a photoelectric conversion element 400, a transfer transistor 410, and a floating diffusion section 420. Hereinafter, in this specification, the floating diffusion section 420 may be referred to as FD section 420 (FD is an abbreviation of Floating Diffusion). Also, the FD section 420 may be referred to as a floating diffusion region 420. Further, pixel 100 has a reset transistor 455 for resetting the FD section 420, an amplification transistor 430 for amplifying a signal, and a selection transistor 440. Also, the photoelectric conversion element 400 is electrically connected to a ground voltage node 450. Also, the reset transistor 455 and the amplification transistor 430 are electrically connected to a power supply voltage node 460, and a power supply voltage is supplied. Note that the selection transistor 440 may not be provided. Note that each of the transfer transistor 410, the reset transistor 455, the amplification transistor 430, and the selection transistor 440 may be an N-type MOS transistor or a P-type MOS transistor.

[0027] The photoelectric conversion element 400 is, for example, a photodiode. The photoelectric conversion element 400 is not limited to a photodiode, and may be, for example, a photoelectric conversion film. The photoelectric conversion element 400 receives the light incident on the pixel 100 and generates charges corresponding to the incident light. The reset transistor 455 is driven by a control signal RES. When the reset transistor 455 is turned on, the FD section 420 is reset to a voltage based on the power supply voltage. Then, when the reset transistor 455 is turned off, the reset of the FD section 420 is released. The transfer transistor 410 is driven by a control signal TX. When the transfer transistor 410 is turned on, the charges generated in the photoelectric conversion element 400 are transferred to the FD section 420. The FD section 420 temporarily holds the charges input from the photoelectric conversion element 400 and functions as a charge-voltage conversion section that converts the held charges into a voltage signal. The amplification transistor 430 amplifies the pixel signal converted by the FD section 420. The selection transistor 440, which can be electrically connected to the output line 130, is driven by a control signal SEL, connects the amplification transistor 430 to the output line 130, and outputs the pixel signal amplified by the amplification transistor 430 to the output line 130. Note that the present disclosure can be applied to any of surface-irradiation type and back-irradiation type sensors.

[0028] Note that the configuration of the pixel 100 shown in FIG. 2 is an example, and it may further have transistors. For example, a transistor for changing the capacitance value of the FD section 420 or a transistor for discharging charges from the photoelectric conversion element 400 may be further provided. Also, a configuration may be adopted in which the selection and non-selection states of the pixel 100 are changed by the voltage input from the reset transistor 455 to the FD section 420 without having the selection transistor 440.

[0029] FIG. 3 is an example of a drive timing chart of the photoelectric conversion device according to the present embodiment.

[0030] Figure 3 shows the horizontal axis representing time and the vertical axis representing voltage, and schematically shows the timing of each drive pulse, the reference signal, the voltage of output line 130 (the voltage of the pixel signal), and the output voltage of comparator 160 (comparator output COMPOUT). Also, each control signal shown in FIG. 3 corresponds to each control signal shown in FIGS. 1 and 2. Note that FIG. 3 shows, as an example, the case where low-intensity light is incident on pixel 100. Note that the case where the control signal SEL transitions from a high level to a low level at time t8 and the control signal SEL transitions from a low level to a high level at time t9 is indicated by a dashed line. Note that the case where the control signal SEL is maintained at a high level at times t8 and t9 is indicated by a solid line. First, the latter case will be described.

[0031] Note that the period from time t8 to time t11 when setting the slope of the ramp signal VRAMP used for AD conversion is defined as the first step. Note that the period from time t13 to time t15 when performing AD conversion of the S signal is defined as the second step, and the period from time t2 to time t7 when performing AD conversion of the N signal is defined as the third step. Note that the operation of transferring charges from the photoelectric conversion element 400 of pixel 100 is performed at a plurality of timings. For example, between two consecutive timings among the plurality of timings, the first step and the second step are respectively performed. Note that, among the above-mentioned plurality of timings, between two consecutive timings, in addition to the first step and the second step, the third step may also be performed. The fact that the operation of transferring charges from the photoelectric conversion element of pixel 100 is performed at a plurality of timings includes, for example, the case where it is performed once in each of a plurality of frames. Also, the fact that the operation of transferring charges from the photoelectric conversion element of pixel 100 is performed at a plurality of timings includes, for example, the case where it is performed a plurality of times within one frame.

[0032] Before time t0, the vertical scanning circuit 120 sets the control signal SEL to a high level and selects the row of pixels 100 that outputs pixel signals. At time t0, the vertical scanning circuit 120 sets the control signal RES to a high level and resets the voltage of the FD section 420. At time t1, the vertical scanning circuit 120 sets the control signal RES to a low level. The pixel signal output when the control signal RES is at a low level is the N signal. The N signal is a signal mainly containing the noise components of the pixel 100.

[0033] At time t2, the control signal s2 is at a low level and the control signal s3 is at a high level. As a result, in the switching section 170, the switch 180 is in an on state and the switch 190 is in an off state. Therefore, the first reference signal is input to the comparator 160.

[0034] During the period from time t2 to time t4, the voltage of the ramp signal VRAMP_L increases from the initial value depending on time by the reference signal output circuit 150. Note that the reference signal output circuit 30 can output a plurality of ramp signals VRAMP with different slopes in parallel and input them to the signal processing section 140. The plurality of ramp signals VRAMP with different slopes are, for example, a ramp signal VRAMP_L with a small slope and a ramp signal VRAMP_H with a large slope. In FIG. 3, for example, the ramp signal VRAMP_L is input to the comparator 160 via the switching section 170. Therefore, during the period from time t2 to time t4, based on the result of comparing the pixel signal with the ramp signal VRAMP_L, the pixel signal, which is an analog signal, is converted into a digital signal. The above driving is performed by the control circuit 340 sending control signals to the reference signal output circuit 150 and the switching section 170.

[0035] At time t2, the voltage change of the ramp signal VRAMP_L is started, and the counter circuit 310 starts counting the clock pulse signal and supplies the count signal CNT to the first memory circuit 270 of each column. At time t3, the voltage of the ramp signal VRAMP_L falls below the pixel signal, and the signal value of the comparator output COMPOUT output by the comparator 160 changes. The first memory circuit 270 holds the value of the count signal CNT at this time. The value of the count signal CNT held by the first memory circuit 270 at this time is the digital value obtained by AD-converting the N signal using the ramp signal VRAMP_L. At time t4, the voltage change depending on the time of the ramp signal VRAMP_L is stopped and reset to the state at time t0. The counter circuit 310 stops counting the clock pulse signal and returns the count signal CNT to the initial value.

[0036] At time t5, the control signal s3 transitions from the high level to the low level. As a result, in the switching unit 170, the switch 180 is turned off and the switch 190 is turned on. Therefore, the second reference signal is input to the comparator 160.

[0037] During the period from time t5 to time t7, the voltage of the ramp signal VRAMP_H increases from the initial value depending on the time by the reference signal output circuit 150. Note that the reference signal output circuit 30 can output a plurality of ramp signals VRAMP with different slopes in parallel and input them to the signal processing unit 140. In FIG. 3, for example, the ramp signal VRAMP_H is input to the comparator 160 via the switching unit 170. Therefore, during the period from time t2 to time t7, based on the result of comparing the pixel signal and the ramp signal VRAMP_H, the pixel signal, which is an analog signal, is converted into a digital signal. The above driving is performed by the control circuit 340 sending control signals to the reference signal output circuit 150 and the switching unit 170.

[0038] At time t5, the voltage change of the ramp signal VRAMP_H is started, and the counter circuit 310 starts counting the clock pulse signal and supplies the count signal CNT to the second memory circuit 280 of each column. At time t6, the voltage of the ramp signal VRAMP_H falls below the pixel signal, and the signal value of the comparator output COMPOUT output by the comparator 160 changes. The second memory circuit 280 holds the value of the count signal CNT at this time. The value of the count signal CNT held by the second memory circuit 280 at this time is the digital value obtained by AD-converting the N signal using the ramp signal VRAMP_H. At time t7, the voltage change depending on the time of the ramp signal VRAMP_H is stopped and reset to the state at time t0. The counter circuit 310 stops counting the clock pulse signal and returns the count signal CNT to its initial value.

[0039] In this embodiment, the AD conversion of the N signal is performed using both the ramp signal VRAMP_L and the ramp signal VRAMP_H. However, the AD conversion of the N signal may be performed using only one of the ramp signals. In that case, by using the ramp signal VRAMP_L as a reference signal, the amount of voltage change per unit time is smaller than when the ramp signal VRAMP_H is used, so that high-resolution AD conversion can be performed.

[0040] Also, at time t7, the control signal s3 transitions from a low level to a high level. As a result, in the switching unit 170, the switch 180 is turned on and the switch 190 is turned off. Therefore, the first reference signal is input to the comparator 160.

[0041] At time t8, the control signal TX is set to a high level, and at time t10, the control signal TX is set to a low level. As a result, the charge generated by the light incident on the photoelectric conversion element 400 is transferred to the FD section 420. The amplification transistor 430 outputs a voltage signal based on the charge transferred to the FD section 420. This voltage signal is output to the output line 130 via the selection transistor 440, and the pixel signal is input to one input terminal of the comparator 160. This signal is the S signal, which is one of the pixel signals. The S signal is an analog signal having a voltage corresponding to the amount of light received by the photoelectric conversion element 400 during one frame period. Here, immediately after the control signal TX becomes high level, the wiring that outputs the control signal TX is coupled to the FD section 420 via the parasitic capacitance between the gate and source of the transfer transistor 410, so that the voltage of the FD section 420 increases. Then, when low-intensity light is incident on the photoelectric conversion element 400, the amount of decrease in the voltage of the FD section 420 due to the charge transferred from the photoelectric conversion element 400 to the FD section 420 exceeds the amount of increase in the above-described voltage. Therefore, the voltage of the FD section 420 temporarily increases, and accordingly, the voltage of the output line 130 also increases. When the control signal TX becomes low level at time t10, the voltage of the FD section 420 decreases due to the coupling between the wiring that outputs the control signal TX and the FD section 420, and the voltage of the output line 130 settles to the voltage value corresponding to the S signal.

[0042] During the period from time t8 to time t12, the reference signal output circuit 30 inputs a threshold voltage VREF as a first reference signal to the other input terminal of the comparator 160. The threshold voltage VREF is output by the reference signal output circuit 150 and input to the comparator 160 via the switching unit 170. This threshold voltage VREF is used as a threshold for determining whether to select the ramp signals VRAMP_L or VRAMP_H as the ramp signal for AD-converting the pixel signal.

[0043] During the period from time t8 to time t11, the comparator 160 compares the threshold voltage VREF with the pixel signal. When the voltage of the pixel signal is higher than the threshold voltage VREF (when the signal amplitude of the pixel signal is smaller than the threshold voltage VREF), the comparator output COMPOUT changes from high level to low level. The comparator output COMPOUT based on the result of comparing the threshold voltage VREF with the pixel signal is input to the selection unit 200. Then, the selection unit 200 controls the switching unit 170 to select the ramp signal VRAMP_L and input it to the comparator 160. When the voltage of the pixel signal is higher than the threshold voltage VREF (when the signal amplitude is small), the ramp signal VRAMP_L with a small slope will be used for AD conversion. That is, based on the comparison result of the first step, the ramp signal VRAMP_L (the first reference signal) is used in the second step.

[0044] When the voltage of the pixel signal is lower than the threshold voltage VREF (when the signal amplitude of the pixel signal is larger than the threshold voltage VREF), the comparator output COMPOUT remains at high level. The comparator output COMPOUT based on the result of comparing the threshold voltage VREF with the pixel signal is input to the selection unit 200. Then, the selection unit 200 controls the switching unit 170 to select the ramp signal VRAMP_H and input it to the comparator 160. When the voltage of the pixel signal is lower than the threshold voltage VREF (when the signal amplitude is large), the ramp signal VRAMP_H with a larger slope than the ramp signal VRAMP_L will be used for AD conversion. That is, based on the comparison result of the first step, the ramp signal VRAMP_H (the second reference signal) is used in the second step.

[0045] With the above driving method, AD conversion can be performed with an appropriate resolution according to the signal output level of the pixel signal. That is, it is possible to achieve a high dynamic range and high-speed driving. Note that FIG. 3 shows a case where the voltage of the pixel signal corresponding to low-intensity light is higher than the threshold voltage VREF, and the ramp signal VRAMP_L is used in the second step.

[0046] Here, at time t8, the control signal s1 transitions from a low level to a high level, and at time t11, the control signal s1 transitions from a high level to a low level. As a result, during the period from time t8 to time t11, the value of the comparator output COMPOUT is held in the fourth memory circuit 210.

[0047] At time t11, the determination of which of the ramp signals VRAMP_H (the second reference signal) and VRAMP_L (the first reference signal) to use during the AD conversion period of the S signal is completed, and at time t12, the voltage of the reference signal is reset.

[0048] At time t13, the control signal s2 transitions from a low level to a high level. As a result, the comparison result held by the fourth memory circuit 210 is input to the switching unit 170. In FIG. 3, since the fourth memory circuit 210 holds a low-level value, in the switching unit 170, the switch 180 is turned on and the switch 190 is turned off. Therefore, the first reference signal is input to the comparator 160.

[0049] During the period from time t13 to time t15, the reference signal output circuit 150 increases the voltage of the ramp signal VRAMP_L or the ramp signal VRAMP_H from the initial value depending on time. Then, the pixel signal is compared with the ramp signal VRAMP_L or the ramp signal VRAMP_H. Further, based on the comparison result, the pixel signal is converted into a digital signal. Which of the ramp signals VRAMP_L and VRAMP_H each signal processing unit 140 inputs to the comparator 160 is determined according to the value of the comparator output COMPOUT during the period from time t8 to time t11. In the case of FIG. 3, if the voltage of the pixel signal during the period from time t8 to time t11 is higher than the threshold voltage VREF, the ramp signal VRAMP_L with a smaller slope is selected.

[0050] At time t13, the voltage change of the ramp signal VRAMP_L or the ramp signal VRAMP_H starts, and at the same time, the counter circuit 310 starts counting the clock pulse signal and supplies the count signal CNT to the third memory circuit 290 of each column.

[0051] At time t14, the voltage of the ramp signal VRAMP_L or the ramp signal VRAMP_H falls below the pixel signal, and the signal value of the comparator output COMPOUT changes. The third memory circuit 290 holds the value of the count signal CNT at this time. The value of the count signal CNT held by the third memory circuit 290 at this time is the digital value obtained by AD-converting the S signal.

[0052] At time t15, the time-dependent voltage change of the ramp signal VRAMP_L or the ramp signal VRAMP_H is stopped and reset to the state at time t0. The counter circuit 310 stops counting the clock pulse signal and returns the count signal CNT to its initial value.

[0053] After time t15, the signal processing unit 140 is sequentially operated by the horizontal scan signal output from the horizontal scan circuit 320, and the signals held in the first memory circuit 270 and the second memory circuit 280 are sent to the output circuit 330. Also, after time t15, the signal processing unit 140 is sequentially operated by the horizontal scan signal output from the horizontal scan circuit 320, and the signals held in the third memory circuit 290 and the fourth memory circuit 210 are sent to the output circuit 330. In the case of FIG. 3, the selector circuit 300 sends the signal held in the first memory circuit 270, which is selected using the signal held in the fourth memory circuit 210, to the output circuit 330.

[0054] In the output circuit 330, a differential signal level (optical component) obtained by subtracting the digitized N signal from the digitized S signal is calculated. Then, the calculated signal is output to the outside of the photoelectric conversion device. Depending on the signal sent from the fourth memory circuit 210, different arithmetic processing may be performed in the output circuit 330. For example, the output circuit 330 may give different gains to the signals based on the ratio of the slopes of the ramp signal VRAMP_L and the ramp signal VRAMP_H. Also, the output circuit 330 may perform correction processing for the offset difference caused by the start timing of the slope operation of the ramp signal VRAMP and the signal propagation delay amount.

[0055] As described above, when a pixel signal corresponding to low-intensity light is output, by selecting a ramp signal VRAMP_L with a smaller slope and performing AD conversion, random noise due to quantization error or the like can be reduced, and high-precision AD conversion can be performed.

[0056] In the above driving, since the value of the comparator output COMPOUT is held in the fourth memory circuit 210 during the period from time t8 to time t11, the voltage error of the output line 130 at time t11 can affect the comparison result between the voltage of the pixel signal and the threshold voltage VREF. On the other hand, when the control signal SEL transitions from a high level to a low level at time t8, the selection transistor 440 is in an off state in FIG. 2. Therefore, as indicated by the broken line in FIG. 3, the voltage of the output line 130 decreases due to the current sink operation of the current source 135. Thereby, the accuracy of determining the magnitude of the voltage value (signal amplitude value) of the pixel signal can be improved.

[0057] As shown in FIG. 3, the voltage of the output line 130 at time t11 has less error in the case of the broken line than in the case of the solid line. In other words, the voltage of the output line 130 at time t11 is closer to the final static value in the case of the broken line than in the case of the solid line. Thus, by driving the control signal SEL to a low level temporarily and turning off the selection transistor 440 temporarily, the voltage of the output line 130 can be decreased by using the current sink operation of the current source 135. And the accuracy of comparison between the voltage of the pixel signal and the threshold voltage VREF can be improved.

[0058] Note that the timing at which the control signal TX transitions from a low level to a high level is set as the first timing (time t8). Note that the timing at which the comparison between the pixel signal based on the signal charge transferred to the floating diffusion region at the first timing and the threshold voltage is completed is set as the second timing (time t11). That is, by performing the first driving that changes the connection state between the pixel 100 and the current source 135 from a conductive state to a non-conductive state between the first timing and the second timing, the determination accuracy can be improved and a high-quality signal can be output.

[0059] FIG. 4 is an example of a drive timing chart of the photoelectric conversion device according to the present embodiment. Note that the same reference numerals are given to the same elements as in FIG. 3, and the description of the drive similar to that in FIG. 3 may be omitted or simplified.

[0060] In FIG. 4, the horizontal axis represents time and the vertical axis represents voltage, schematically showing the timing of each drive pulse, the reference signal, the voltage of output line 130 (the voltage of the pixel signal), and the output voltage of comparator 160 (comparator output COMPOUT). In addition, each control signal shown in FIG. 4 corresponds to each control signal shown in FIGS. 1 and 2. Note that FIG. 4 shows a case where high-intensity light is incident on pixel 100 as an example. A case where the control signal SEL transitions from a high level to a low level at time t8 and the control signal SEL transitions from a low level to a high level at time t9 is indicated by a broken line. A case where the control signal SEL is maintained at a high level at times t8 and t9 is indicated by a solid line.

[0061] FIG. 4 is different from FIG. 3 in that when the control signal TX is set to a high level at time t8, the charge generated corresponding to high-intensity light rather than low-intensity light is transferred to the FD section 420. Therefore, the voltage of the pixel signal corresponding to high-intensity light is lower than the threshold voltage VREF, and in the second step, the ramp signal VRAMP_H (the second reference signal) is used. When a pixel signal corresponding to high-intensity light is output, the ramp signal VRAMP_H with a larger slope is selected for AD conversion. By such driving, the readout time of the pixel signal can be shortened. Although the random noise due to quantization error or the like increases, the influence of the random noise becomes relatively small because the optical shot noise is dominant when high-intensity light is incident.

[0062] Note that also in FIG. 4, immediately after the control signal TX becomes high level at time t8, the voltage of the FD section 420 increases by coupling the wiring that outputs the control signal TX to the FD section 420. However, when high-intensity light is incident on the photoelectric conversion element 400, the amount of voltage drop of the FD section 420 due to the charge transferred from the photoelectric conversion element 400 to the FD section 420 exceeds the above-described amount of voltage increase. Therefore, after time t8, the voltage of the output line 130 also decreases in response to the voltage drop of the FD section 420, and the voltage of the output line 130 settles to a voltage value corresponding to the S signal.

[0063] Similar to FIG. 3, also in FIG. 4, the voltage error of the output line 130 at time t11 can affect the comparison result between the voltage of the pixel signal and the threshold voltage VREF. When the control signal SEL transitions from high level to low level at time t8, the selection transistor 440 is turned off in FIG. 2. Therefore, as indicated by the broken line in FIG. 4, the voltage of the output line 130 decreases due to the current sink operation of the current source 135. Thereby, the accuracy of determining the magnitude of the voltage value (signal amplitude value) of the pixel signal can be improved.

[0064] As shown in FIG. 4, the voltage of the output line 130 at time t11 has less error in the case of the broken line than in the case of the solid line. In other words, in the case of the broken line, the voltage of the output line 130 at time t11 becomes closer to the final settled value than in the case of the solid line. Thus, by driving the control signal SEL to be temporarily low level and the selection transistor 440 to be temporarily off, the voltage of the output line 130 can be decreased using the current sink operation of the current source 135. And the accuracy of the comparison between the voltage of the pixel signal and the threshold voltage VREF can be improved.

[0065] Note that the timing at which the control signal TX transitions from a low level to a high level is defined as the first timing (time t8). Note that the timing at which the comparison between the pixel signal based on the signal charge transferred to the floating diffusion region at the first timing and the threshold voltage is completed is defined as the second timing (time t11). That is, by performing the first drive to change the connection state between the pixel 100 and the current source 135 from a conductive state to a non-conductive state between the first timing and the second timing, the determination accuracy can be improved, and a high-quality signal can be output.

[0066] Note that in FIGS. 3 and 4, an example in which the control signal SEL transitions from a high level to a low level during a period in which the control signal TX is at a high level is shown, but it is not limited to this. For example, in FIGS. 3 and 4, the control signal SEL may transition from a high level to a low level between the time t10 when the control signal TX becomes a low level and the time t11 when the determination of the magnitude of the voltage value of the pixel signal is completed. In other words, the above effect can be obtained if the control signal SEL is set to a low level during the period from when the control signal TX becomes a high level until the determination is completed. Note that since the period during which the control signal SEL is at a low level overlaps with the period during which the control signal TX is at a high level, it is possible to suppress the temporary increase in the voltage of the output line 130 in response to the voltage increase of the FD unit 420, and thus a higher effect can be obtained. Note that the timing at which the control signal TX transitions from a high level to a low level is defined as the third timing.

[0067] Note that the period during which the control signal SEL is set to a low level may be changed according to the operation mode. For example, in an operation mode in which the current of the current source 135 is large, the period during which the control signal SEL is maintained at a low level may be shortened. An example is shown in FIG. 5.

[0068] FIG. 5 is an example of a drive timing chart of the photoelectric conversion device according to the present embodiment. Note that the same reference numerals are assigned to the same elements as in FIGS. 3 and 4, and the description of the same drive as in FIGS. 3 and 4 may be omitted or simplified.

[0069] FIG. 5 shows the horizontal axis representing time and the vertical axis representing voltage, schematically showing the timing of each drive pulse and the voltage of output line 130 (the voltage of the pixel signal). Also, each control signal shown in FIG. 4 corresponds to each control signal shown in FIGS. 1 and 2. Note that FIG. 5(a) shows the first operation mode in which the first current flows through current source 135, and FIG. 5(b) shows the second operation mode in which a second current larger than the first current flows through current source 135. Note that FIG. 5 shows, as an example, the case where low-intensity light is incident on pixel 100. The case where the control signal SEL transitions from a high level to a low level at time t8 and the control signal SEL transitions from a low level to a high level at time t9 is shown by a dashed line. The case where the control signal SEL is maintained at a high level at times t8 and t9 is shown by a solid line.

[0070] Compared with FIG. 5(a), in FIG. 5(b), the voltage of output line 130 decreases at a faster rate during the period when the control signal SEL is at a low level from time t8 to t9. Therefore, in FIGS. 5(a) and 5(b), if the periods when the control signal SEL is at a low level are made approximately the same, the time for the voltage of output line 130 to settle to the voltage value corresponding to the S signal may be different between different operation modes. That is, the second operation mode with a larger current in the current source requires more time for the voltage of output line 130 to settle to the voltage value corresponding to the S signal than the first operation mode with a smaller current in the current source. Therefore, in FIG. 5, in the second operation mode with a large current, by relatively shortening the period in which the control signal SEL is at a low level, control is performed so that the settling time of output line 130 is approximately the same even in different operation modes. That is, optimal processing is performed according to different operation modes, the accuracy of determining the magnitude of the voltage value (signal amplitude value) of the pixel signal is improved, and a high-quality signal is output.

[0071] Note that the operation mode may be switched by a method other than changing the current value of the current source 135. For example, a plurality of comparators 160 electrically connectable to one output line 130 may be provided, and the operation mode may be switched by changing the number of comparators 160 electrically connected to one output line 130. For example, when a plurality of comparators 160 are connected to one output line 130, the capacitance associated with the output line 130 increases. Therefore, the rate at which the voltage of the output line 130 decreases during the period when the control signal SEL is at a low level becomes slow. In the above case, by making the period during which the control signal SEL is at a low level longer for an operation mode in which the number of comparators 160 connected to one output line 130 is larger, the time for the output line 130 to settle is controlled to be approximately the same even in different operation modes.

[0072] Note that in FIG. 3, by setting the control signal SEL to a low level, the selection transistor 440 is turned off in FIG. 2, so that the current supplied from the power supply voltage node 460 becomes zero. As a result, the power supply voltage of the pixel array 110 unit in FIG. 1 may fluctuate. When this fluctuation propagates to the comparator 160, it may cause deterioration in the determination accuracy of the voltage value (signal amplitude value) of the pixel signal. Therefore, it is desirable that the power supply of the pixel array unit 110 and the power supply of the comparator 160 be provided as separate systems and input from different input pads respectively. In other words, by separating the electrical paths for supplying the power supply voltage to the power supply of the pixel array unit 110 and the element for determining the voltage value (signal amplitude value) of the pixel signal, the determination accuracy can be improved.

[0073] The photoelectric conversion device according to the first modification of the first embodiment of the present invention will be described with reference to FIG. 6. Note that the same reference numerals are assigned to the same components as those in the first embodiment, and the description of these components may be omitted or simplified.

[0074] The first modification of the first embodiment is different from the first embodiment in that the pixel array unit 110 and the signal processing unit 140 are arranged in a stacked structure on different substrates. FIG. 6 is an example of a block diagram of the photoelectric conversion device according to this modification.

[0075] As shown in FIG. 6, the pixel substrate 1 includes a pixel array portion 110, a vertical scanning circuit 120, and an output line 130. The circuit substrate 2 includes an output line 130′, a current source 135, a signal processing unit 140, a reference signal output circuit 150, a counter circuit 310, a horizontal scanning circuit 320, an output circuit 330, and a control circuit 340.

[0076] In this modification example, the pixel substrate 1 and the circuit substrate 2 can be optimized in the manufacturing process by applying a process specialized for pixels and circuits respectively.

[0077] The photoelectric conversion device according to the second modification example of the first embodiment of the present invention will be described with reference to FIGS. 7 and 8. Note that the same reference numerals are given to the same components as those in the first embodiment, and the description of these components may be omitted or simplified.

[0078] The second modification example of the first embodiment is different from the first embodiment in that a switch is provided between the pixel 100 and the current source 135. FIG. 7 is an example of a block diagram of the photoelectric conversion device according to this modification example.

[0079] As shown in FIG. 7, the photoelectric conversion device includes a switch 350. The switch 350 is provided between the pixel 100 and the current source 135. The switch 350 is driven by a control signal VLIN. In this modification example, the same driving as in the first embodiment is performed using the switch 350 instead of the selection transistor 440.

[0080] FIG. 8 is an example of a timing chart of the photoelectric conversion device according to this modification example.

[0081] FIG. 8 shows the horizontal axis representing time and the vertical axis representing voltage, schematically showing the timing of each drive pulse and the voltage of output line 130 (the voltage of the pixel signal). Also, each control signal shown in FIG. 8 corresponds to each control signal shown in FIGS. 1, 2, and 7. Note that FIG. 8 shows, as an example, the case where low-intensity light is incident on pixel 100. The case where the control signal VLIN transitions from a high level to a low level at time t8 and the control signal VLIN transitions from a low level to a high level at time t9 is shown by a dashed line. The case where the control signal VLIN is maintained at a high level at times t8 and t9 is shown by a solid line.

[0082] When the control signal VLIN transitions from a high level to a low level at time t8, the switch 350 is in an off state in FIG. 7. Therefore, as shown by the dashed line in FIG. 8, the voltage of output line 130 decreases due to the current sink operation of current source 135. This improves the accuracy of determining the magnitude of the voltage value (signal amplitude value) of the pixel signal, and a high-quality signal can be output.

[0083] The photoelectric conversion device according to the third modification of the first embodiment of the present invention will be described with reference to FIGS. 9 and 10. Note that the same reference numerals are given to the same components as those in the first embodiment, and the description of these components may be omitted or simplified.

[0084] In the second modification of the first embodiment, a switch is provided between the pixel and the current source on one output line corresponding to one current source. On the other hand, in the third modification of the first embodiment, switches are respectively provided between the pixel and the current source on two output lines corresponding to one current source. FIG. 9 is an example of a circuit diagram of the photoelectric conversion device according to this modification.

[0085] As shown in FIG. 9, the photoelectric conversion device includes output lines 130-1, output lines 130-2, switches 350-1, and 350-2. The output lines 130-1 and 130-2 can be electrically connected to the pixel 100. The switch 350-1 is provided between the pixel 100 and the current source 135 and can be electrically connected to the pixel 100 via the output line 130-1. The switch 350-2 is provided between the pixel 100 and the current source 135 and can be electrically connected to the pixel 100 via the output line 130-2. Also, the switch 350-1 is driven by the control signal VLIN1, and the switch 350-2 is driven by the control signal VLIN2.

[0086] FIG. 10 is an example of a timing chart of the photoelectric conversion device according to this modified example.

[0087] In FIG. 10, the horizontal axis represents time and the vertical axis represents voltage, schematically showing the timing of each drive pulse. Also, each control signal shown in FIG. 10 corresponds to each control signal shown in FIGS. 1, 2, and 9. During the period from time t1 to t5, the output line 130-1 is read, and after time t5, the output line 130-2 is read.

[0088] In FIG. 10, during each of the periods from time t21 to t22, from time t23 to t24, from time t26 to t27, and from time t28 to 29, the control signal TX is at a high level. During the period from time t21 to t25, since the readout of output line 130-1 is performed, the control signal VLIN1 is at a high level. However, during each of the periods from time t21 to t22 and from time t23 to t24 within that period, the control signal VLIN1 is at a low level. During the period after time t25, since the readout of output line 130-2 is performed, the control signal VLIN2 is at a high level. However, during each of the periods from time t25 to t26 and from time t27 to t28 within that period, the control signal VLIN2 is at a low level. With such driving, during the period when the control signal TX is at a high level, switch 350-1 or switch 350-2 is turned off. Thereby, the accuracy of determining the magnitude of the voltage value (signal amplitude value) of the pixel signal can be improved, and a high-quality signal can be output. Further, by sequentially reading out the two output lines, output line 130-1 and output line 130-2, instead of a single output line 130, the parasitic capacitance of the output line when reading the pixel signal can be reduced, and the operating speed can be improved. In this modified example, by using switch 350-1 or switch 350-2, not only the determination accuracy can be improved but also the operating speed can be improved.

[0089] <Second Embodiment> The photoelectric conversion device according to the second embodiment of the present invention will be described with reference to FIGS. 11 and 12. Note that the same reference numerals are given to the same components as those in the first embodiment, and the description of these components may be omitted or simplified.

[0090] This embodiment is different from the first embodiment in that it has a pulse current source as a high-speed circuit. FIG. 11 is an example of a circuit diagram of the photoelectric conversion device according to this embodiment.

[0091] As shown in FIG. 11, the photoelectric conversion device includes a pulse current source 510 and a current source 520. The pulse current source 510 has a switch 511 and a current source 512. The current source 512 can be electrically connected to the output line 130, and the switch 511 is disposed between the output line 130 and the current source 512. Further, the switch 511 is driven by a control signal IP_IN. The current source 520 has a cascode transistor 521 and a current source transistor 522.

[0092] FIG. 12 is an example of a timing chart of the photoelectric conversion device according to the present embodiment.

[0093] In FIG. 12, the horizontal axis represents time and the vertical axis represents voltage, schematically showing the timing of each drive pulse and the voltage of the output line 130 (voltage of the pixel signal). Also, each control signal shown in FIG. 12 corresponds to each control signal shown in FIGS. 1, 2, and 11. Note that FIG. 12 shows a case where low-intensity light is incident on the pixel 100 as an example. A case where the control signal IP_IN transitions from a low level to a high level at time t10 and the control signal IP_IN transitions from a high level to a low level at time t9 is shown by a broken line. A case where the control signal VLIN is maintained at a low level at times t10 and t9 is shown by a solid line.

[0094] By setting the control signal TX to a high level at time t8, the voltage of the output line 130 can temporarily increase when outputting a pixel signal corresponding to low-intensity light, similar to the first embodiment. Also, by setting the control signal TX to a low level at time t10, the voltage of the output line 130 decreases.

[0095] When the control signal VLIN transitions from a low level to a high level at time t10, the switch 511 is turned on in FIG. 11. Then, the sink current for the output line 130 increases according to the amount of current of the current source 512. For this reason, as indicated by the dashed line in FIG. 12, the voltage drop of the output line 130 is accelerated by the current sink operation. That is, between the first timing and the second timing, by changing the connection state of the high-speed circuit and the output line 130 from a non-conductive state to a conductive state, the output line 130 outputs a pixel signal to the comparator 160 along with the operation of the high-speed circuit.

[0096] After the signal processing is accelerated using the pulse current source 510 as the high-speed circuit as described above, by determining the magnitude of the voltage value (signal amplitude value) of the pixel signal, the determination accuracy can be improved and a high-quality signal can be output.

[0097] <Third Embodiment> The photoelectric conversion device according to the third embodiment of the present invention will be described with reference to FIG. 13. Note that the same reference numerals are assigned to the same components as in the first and second embodiments, and the description of these components may be omitted or simplified.

[0098] This embodiment is different from the first and second embodiments in that it has a negative capacitance circuit as the high-speed circuit. FIG. 13 is an example of a circuit diagram of the photoelectric conversion device according to this embodiment.

[0099] As shown in FIG. 13, the photoelectric conversion device includes a negative capacitance circuit 530. The negative capacitance circuit 530 includes an amplifier 531 and a capacitive element 532. The capacitive element 532 can be electrically connected to the output line 130, and the amplifier 531 is arranged between the output line 130 and the capacitive element 532.

[0100] By using the negative capacitance circuit 530, signal processing can be accelerated. Here, let the gain of the amplifier 531 be A and the capacitance of the capacitive element 532 be C. Under certain conditions, the negative capacitance circuit 530 functions as a capacitance of -(A×C). That is, between the first timing and the second timing, with the operation of the acceleration circuit, the output line 130 outputs a pixel signal to the comparator 160.

[0101] Due to the above drive, the capacitance associated with the output line 130 is effectively reduced, so that the negative capacitance circuit functions as an acceleration circuit, enabling acceleration of signal processing. After accelerating the signal processing, by determining the magnitude of the voltage value (signal amplitude value) of the pixel signal, the determination accuracy can be improved and a high-quality signal can be output.

[0102] <Fourth Embodiment> The photoelectric conversion device according to the fourth embodiment of the present invention will be described with reference to FIGS. 14 and 15. Note that the same reference numerals are given to the same components as in the first, second, and third embodiments, and the descriptions of these components may be omitted or simplified.

[0103] This embodiment is different from the first, second, and third embodiments in that it has a configuration with a limiting circuit. FIG. 14 is an example of a circuit diagram of the photoelectric conversion device according to this embodiment.

[0104] As shown in FIG. 14, the photoelectric conversion device includes a clip transistor 540. The clip transistor 540 functions as a limiting circuit and limits the range in which the voltage of the output line 130 can change.

[0105] FIG. 15 is an example of a timing chart of the photoelectric conversion device according to this embodiment.

[0106] FIG. 15 shows the horizontal axis as time and the vertical axis as voltage, and schematically shows the timing of each drive pulse and the voltage of output line 130 (the voltage of the pixel signal). Also, each control signal shown in FIG. 15 corresponds to each control signal shown in FIGS. 1 and 2. Note that FIG. 15 shows a case where low-intensity light is incident on pixel 100 as an example. Note that the case of having the clip transistor 540 is shown by a broken line. Note that the case of not having the clip transistor 540 is shown by a solid line.

[0107] By setting the control signal TX to a high level at time t8, when outputting a pixel signal corresponding to low-intensity light as in the first embodiment, the voltage of output line 130 can temporarily increase. Also, by setting the control signal TX to a low level at time t10, the voltage of output line 130 decreases.

[0108] When having the clip transistor 540, during the period from time t8 to time t10, when the voltage of output line 130 reaches a predetermined value, the clip transistor 540 transitions from a non-operating state to an operating state, and the increase in the voltage of output line 130 is suppressed. That is, between the first timing and the second timing, the state of the limiting circuit changes from a non-operating state to an operating state.

[0109] Therefore, by using the clip transistor 540 to suppress the increase in the voltage of output line 130 and then determining the magnitude of the voltage value (signal amplitude value) of the pixel signal, the determination accuracy can be improved and a high-quality signal can be output. Note that as the limiting circuit, a configuration including the clip transistor 540 is shown, but it is not limited to this example. The limiting circuit may be any circuit that limits the range in which the voltage of output line 130 changes. For example, it is also possible to apply the configuration of the clip unit 109 described in each embodiment of Japanese Unexamined Patent Application Publication No. 2021-87200.

[0110] <Fifth Embodiment> The photoelectric conversion device according to the fifth embodiment of the present invention will be described with reference to FIG. 16. Note that the same reference numerals are given to the same components as in the first, second, third, and fourth embodiments, and the description of these components may be omitted or simplified.

[0111] This embodiment is different from the first to fourth embodiments in that, instead of optimizing the reference signal according to the result of determining the magnitude of the voltage value (signal amplitude value) of the pixel signal, the gain amount applied to the pixel signal is optimized. FIG. 16 is an example of a circuit diagram of the photoelectric conversion device according to this embodiment.

[0112] As shown in FIG. 16, the photoelectric conversion device includes a capacitive element 550, an amplifier 560, a variable capacitor 570, and a determination circuit 580. Note that the amplifier 560 is disposed between the pixel 100 and the comparator 160. In the determination circuit 580, the magnitude of the voltage value (signal amplitude value) of the pixel signal is determined, and the variable capacitor 570 is controlled according to the determination result. Then, the gain amount applied to the pixel signal output from the pixel 100 is determined according to the ratio of the capacitive element 550 and the variable capacitor 570. That is, according to the determination result of the magnitude of the voltage value (signal amplitude value) of the pixel signal, the gain amount applied to the pixel signal input to the comparator 160 can be made variable.

[0113] Note that the fifth embodiment is applicable to any of the first to fourth embodiments. Even with such a configuration, by driving to cut off the path from the pixel 100 to the current source 135, using a high-speed circuit or a limiting circuit, the determination accuracy can be improved and a high-quality signal can be output.

[0114] <Sixth Embodiment> The photoelectric conversion device according to the fifth embodiment of the present invention will be described with reference to FIG. 17. Note that the same reference numerals are given to the same components as in the first to fifth embodiments, and the description of these components may be omitted or simplified.

[0115] This embodiment is different from the first to fifth embodiments in that it performs delta-sigma (ΔΣ) type AD conversion instead of slope type AD conversion. FIG. 17 is an example of a circuit diagram of a photoelectric conversion device according to this embodiment.

[0116] As shown in FIG. 17, the photoelectric conversion device includes a determination circuit 600, a first sample-and-hold circuit 710, a second sample-and-hold circuit 711, and a conversion unit 799. The determination circuit 600, the first sample-and-hold circuit 710, the second sample-and-hold circuit 711, and the conversion unit 799 are arranged corresponding to the output line 130. The first sample-and-hold circuit 710 samples and holds the N signal output from the pixel when resetting the photoelectric conversion element 400, as will be described later. The second sample-and-hold circuit 711 samples and holds the S signal generated in response to the incident light on the photoelectric conversion element.

[0117] The first sample-and-hold circuit 710 includes a capacitive element 620 and an inverting amplifier 605. The switch 610 controls the connection between the output line 130 and the capacitive element 620 according to the control signal Smp_n. The inverting amplifier 605 can be configured by a combination of a source-grounded circuit and a source follower circuit. The inverting amplifier 605 includes transistors 630, 640, 650, 660, 730, switches 670, 680, 690, and a current source 700. The switch 670 is connected between the input and output of the source-grounded circuit composed of the transistors 630, 640, 650, 660 and is controlled by the control signal Smpa_n. The signal from the inverting amplifier 605 can be output according to the control signal Hld_n.

[0118] The second sample hold circuit 711 has the same configuration as the first sample hold circuit 710. The second sample hold circuit 711 includes a capacitive element 621 and an inverting amplifier 606. The switch 611 controls the connection between the output line 130 and the capacitive element 621 according to the control signal Smp_n. The inverting amplifier 606 can be configured by a combination of a source grounding circuit and a source follower circuit. The inverting amplifier 606 includes transistors 631, 641, 651, 661, 731, switches 671, 681, 691, and a current source 701. The switch 671 is connected between the input and output of the source grounding circuit composed of the transistors 631, 641, 651, 661, and is controlled by the control signal Smpa_n. The signal from the inverting amplifier 606 can be output according to the control signal Hld_n.

[0119] A variable resistance element 740 is arranged between the output terminal of the first sample hold circuit 710 and the output terminal of the second sample hold circuit 711. Consider the case where the first sample hold circuit 710 outputs an N signal and the second sample hold circuit 711 outputs an S signal. Let the potential at the output terminal of the first sample hold circuit 710, that is, the potential of the N signal, be Vn, and the potential at the output terminal of the second sample hold circuit 711, that is, the potential of the S signal, be Vs. Let the resistance value of the variable resistance element 740 be R. Thus, the current I flowing through the variable resistance element 740 is represented by the following (Equation 1). I = (Vn - Vs) / R (Equation 1)

[0120] This current I is input to the conversion unit 799. At this time, as shown in Equation 1, the current I flowing through the variable resistance element 740 is proportional to the difference between the potential Vn of the N signal and the potential Vs of the S signal of the pixel signal. Therefore, CDS (correlated double sampling) is being performed at the stage when the current I is input to the conversion unit 799. Also, the determination circuit 600 determines the magnitude of the voltage value (signal amplitude value) of the pixel signal, and controls the resistance value of the variable resistance element 740 according to the determination result. By such driving, the gain amount applied to the pixel signal input to the conversion unit 799 can be made variable.

[0121] The conversion unit 799 is an oversampling type AD conversion circuit, for example, a ΔΣ type AD conversion circuit. The ΔΣ type AD conversion circuit includes a first integrator, a second integrator, a quantizer 790, and a decimation filter 795. In the conversion unit 799, the first integrator includes an integration capacitor 760. The second integrator includes a voltage-current conversion circuit (Gm cell) 765 that converts voltage to current and an integration capacitor 785. An AD converter 750 including a current source 745 and a switch 755 is connected to the input node of the first integrator.

[0122] The AD converter 750 controls the current to the first integrator according to the digital signal via the second integrator and the quantizer 790. An AD converter 775 including a current source 770 and a switch 780 is connected to the input node of the second integrator. The AD converter 775 controls the current to the second integrator according to the result of quantizing the output of the second integrator by the quantizer 790.

[0123] In the conversion unit 799, an operation is performed in which the quantizer 790 feeds back the previous quantization value to the second integrator and the first integrator through the AD converters 750 and 775. In this way, by passing through the integrators twice while feeding back the previous quantization value to the AD converters 750 and 775, second-order noise shaping characteristics can be obtained. Further, by removing high-frequency noise by the decimation filter 795 arranged after the quantizer 790, a highly accurate AD conversion output can be obtained.

[0124] <Seventh Embodiment> The seventh embodiment is applicable to the first to sixth embodiments. Fig. 18(a) is a schematic diagram for explaining an apparatus 9191 including a semiconductor device 930 according to this embodiment. In the semiconductor device 930, the photoelectric conversion device (imaging device) of each of the above embodiments can be used. The apparatus 9191 including the semiconductor device 930 will be described in detail. The semiconductor device 930 can include a semiconductor device 910. In addition to the semiconductor device 910, the semiconductor device 930 can include a package 920 that houses the semiconductor device 910. The package 920 can include a substrate to which the semiconductor device 910 is fixed and a lid such as glass facing the semiconductor device 910. The package 920 can further include a bonding member such as a bonding wire or a bump that connects a terminal provided on the substrate and a terminal provided on the semiconductor device 910.

[0125] The apparatus 9191 can include at least any one of an optical device 940, a control device 950, a processing device 960, a display device 970, a storage device 980, and a mechanical device 990. The optical device 940 corresponds to the semiconductor device 930. The optical device 940 is, for example, a lens, a shutter, or a mirror, and includes an optical system that guides light to the semiconductor device 930. The control device 950 controls the semiconductor device 930. The control device 950 is a semiconductor device such as an ASIC.

[0126] The processing device 960 processes a signal output from the semiconductor device 930. The processing device 960 is a semiconductor device such as a CPU or an ASIC for constituting an AFE (analog front end) or a DFE (digital front end). The display device 970 is an EL display device or a liquid crystal display device that displays information (image) obtained by the semiconductor device 930. The storage device 980 is a magnetic device or a semiconductor device that stores information (image) obtained by the semiconductor device 930. The storage device 980 is a volatile memory such as an SRAM or a DRAM, or a non-volatile memory such as a flash memory or a hard disk drive.

[0127] The mechanical device 990 has movable parts or propulsion parts such as motors and engines. In the device 9191, the signal output from the semiconductor device 930 is displayed on the display device 970 or transmitted to the outside by a communication device (not shown) provided in the device 9191. For this purpose, it is preferable that the device 9191 further includes a storage device 980 and a processing device 960 separately from the storage circuit and arithmetic circuit included in the semiconductor device 930. The mechanical device 990 may be controlled based on the signal output from the semiconductor device 930.

[0128] In addition, the device 9191 is suitable for electronic devices such as information terminals having a photographing function (e.g., smartphones and wearable terminals) and cameras (e.g., interchangeable-lens cameras, compact cameras, video cameras, surveillance cameras). The mechanical device 990 in the camera can drive the components of the optical device 940 for zooming, focusing, and shutter operations. Alternatively, the mechanical device 990 in the camera can move the semiconductor device 930 for anti-vibration operation.

[0129] Also, the device 9191 can be a transportation device such as a vehicle, a ship, or an aircraft (drone, airplane, etc.). The mechanical device 990 in the transportation device can be used as a moving device. The device 9191 as a transportation device is suitable for those that transport the semiconductor device 930 or those that assist and / or automate driving (operation) by means of a photographing function. The processing device 960 for assisting and / or automating driving (operation) can perform processing for operating the mechanical device 990 as a moving device based on the information obtained by the semiconductor device 930. Alternatively, the device 9191 may be a medical device such as an endoscope, a measuring device such as a distance measuring sensor, an analysis device such as an electron microscope, an office device such as a copier, or an industrial device such as a robot.

[0130] According to the above-described embodiment, it is possible to obtain good pixel characteristics. Therefore, the value of the semiconductor device can be increased. The increase in value here includes at least any one of function addition, performance improvement, characteristic improvement, reliability improvement, manufacturing yield improvement, environmental load reduction, cost reduction, miniaturization, and weight reduction.

[0131] Therefore, if the semiconductor device 930 according to this embodiment is used in the device 9191, the value of the device can also be improved. For example, when the semiconductor device 930 is mounted on a transportation device to perform external shooting or external environment measurement of the transportation device, excellent performance can be obtained. Therefore, in manufacturing and selling the transportation device, it is advantageous to determine to mount the semiconductor device according to this embodiment on the transportation device in terms of enhancing the performance of the transportation device itself. In particular, the semiconductor device 930 is suitable for a transportation device that performs driving support and / or autonomous driving of the transportation device using the information obtained by the semiconductor device.

[0132] Also, the photoelectric conversion system and the moving body of this embodiment will be described with reference to FIGS. 18(b) and (c).

[0133] FIG. 18(b) shows an example of a photoelectric conversion system related to an in-vehicle camera. The photoelectric conversion system 8 includes a photoelectric conversion device 80. The photoelectric conversion device 80 is the photoelectric conversion device (imaging device) described in any of the above embodiments. The photoelectric conversion system 8 includes an image processing unit 801 that performs image processing on a plurality of pieces of image data acquired by the photoelectric conversion device 80, and a parallax acquisition unit 802 that calculates parallax (phase difference of a parallax image) from the plurality of pieces of image data acquired by the photoelectric conversion system 8. Here, the photoelectric conversion system 8 may include an optical system (not shown) that guides light to the photoelectric conversion device 80, such as a lens, a shutter, or a mirror. Further, a plurality of photoelectric conversion elements substantially conjugate with the pupil of the optical system may be arranged in the pixels included in the photoelectric conversion device 80. For example, a plurality of photoelectric conversion elements substantially conjugate with the pupil are arranged corresponding to one microlens. The plurality of photoelectric conversion elements receive light beams that have passed through different positions of the pupil of the optical system, so that the photoelectric conversion device 80 outputs image data corresponding to the light beams that have passed through different positions. Then, the parallax acquisition unit 802 may calculate parallax using the output image data. Further, the photoelectric conversion system 8 includes a distance acquisition unit 803 that calculates the distance to an object based on the calculated parallax, and a collision determination unit 804 that determines whether there is a possibility of collision based on the calculated distance. Here, the parallax acquisition unit 802 and the distance acquisition unit 803 are examples of distance information acquisition means for acquiring distance information to an object. That is, the distance information is information related to parallax, defocus amount, distance to an object, and the like. The collision determination unit 804 may determine the possibility of collision using any of these distance information. Note that the distance information may be acquired by ToF (Time of Flight). The distance information acquisition means may be realized by dedicatedly designed hardware, or may be realized by a software module. Further, it may be realized by an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), or the like, or may be realized by a combination of these. The photoelectric conversion system 8 is connected to a vehicle information acquisition device 810 and can acquire vehicle information such as vehicle speed, yaw rate, and steering angle.In addition, the photoelectric conversion system 8 is connected to a control ECU 820, which is a control device that outputs a control signal for generating a braking force for the vehicle based on the determination result of the collision determination unit 804. The photoelectric conversion system 8 is also connected to an alarm device 830 that issues an alarm to the driver based on the determination result of the collision determination unit 804. For example, when the determination result of the collision determination unit 804 indicates a high possibility of collision, the control ECU 820 performs vehicle control to avoid the collision and reduce the damage, such as applying the brakes, returning the accelerator, and suppressing the engine output. The alarm device 830 warns the user by sounding an alarm such as a sound, displaying alarm information on the screen of a car navigation system, or applying vibration to the seat belt or steering wheel.

[0134] In this embodiment, the photoelectric conversion system 8 images the surroundings of the vehicle, for example, the front or the rear. Fig. 18(c) shows the photoelectric conversion system 8 when imaging the front of the vehicle (imaging range 850). The vehicle information acquisition device 810 sends an instruction to the photoelectric conversion system 8 or the photoelectric conversion device 80. With such a configuration, the ranging accuracy can be further improved.

[0135] In the above, an example of controlling to avoid collision with other vehicles has been described, but it is also applicable to controls such as automatic driving following other vehicles and automatic driving so as not to deviate from the lane. Furthermore, the photoelectric conversion system 8 can be applied not only to vehicles such as automobiles, but also to moving bodies (mobile devices) such as ships, aircraft, or industrial robots. In addition, it can be applied not only to moving bodies, but also to devices that widely utilize object recognition, such as advanced road traffic systems (ITS).

[0136] In this specification, expressions such as "A or B", "at least one of A and B", "at least one of A or / and B", "one or more of A or / and B" include all possible combinations of the listed items, unless otherwise explicitly defined. That is, the above expressions are understood to disclose all cases including at least one A, including at least one B, and including both at least one A and at least one B. This also applies equally to combinations of three or more elements.

[0137] As described above, the embodiments can be appropriately modified without departing from the technical idea. Note that the disclosure of this specification includes not only what is described in this specification but also all matters that can be grasped from this specification and the drawings attached to this specification. Also, the disclosure of this specification includes the complementary set of the concepts described in this specification. That is, for example, if this specification describes that "A is larger than B", even if the description that "A is not larger than B" is omitted, it can be said that this specification discloses that "A is not larger than B". This is because when the description that "A is larger than B" is given, it is premised that the case where "A is not larger than B" is considered.

[0138] Note that the disclosure of this embodiment includes the following configurations.

[0139] (Method 1) A photoelectric conversion device driving method, comprising: a pixel having a photoelectric conversion element that generates charges according to incident light, a floating diffusion region, and a transfer transistor that transfers the charges to the floating diffusion region; an output line that can be electrically connected to the pixel and outputs a pixel signal based on the charges; and a current source that can be electrically connected to the output line and supplies a current to the output line. At a first timing, the transfer transistor is turned on and the charges are transferred to the floating diffusion region. At a second timing, a comparison between the pixel signal based on the charges transferred to the floating diffusion region at the first timing and a threshold voltage is completed. Between the first timing and the second timing, a first driving is performed to change the connection state between the pixel and the current source from a conductive state to a non-conductive state.

[0140] (Method 2) At a third timing between the first timing and the second timing, the transfer transistor is turned off. Between the first timing and the third timing, the first driving is performed. The driving method of the photoelectric conversion device according to Method 1, characterized in that.

[0141] (Method 3) After performing the first driving between the first timing and the second timing, between the first timing and the second timing, the connection state between the pixel and the current source is changed from a non-conductive state to a conductive state. The driving method of the photoelectric conversion device according to Method 1 or 2, characterized in that.

[0142] (Method 4) A driving method for a photoelectric conversion device having a first operation mode in which a first current is supplied from the current source and a second operation mode in which a second current larger than the first current is supplied from the current source, wherein in the first operation mode, a period during which a connection state between the pixel and the current source is a non-conductive state is longer than a period during which the connection state between the pixel and the current source is a non-conductive state in the second operation mode. The driving method for a photoelectric conversion device according to any one of Methods 1 to 3.

[0143] (Method 5) A driving method for a photoelectric conversion device including a plurality of comparators electrically connectable to the output line and having a plurality of operation modes in which the number of the plurality of comparators electrically connected to the output line is different. In a first operation mode which is one of the plurality of modes, the number of the plurality of comparators electrically connected to the output line is larger than the number of the plurality of comparators electrically connected to the output line in a second operation mode which is one of the plurality of modes. In the first operation mode, a period during which a connection state between the pixel and the current source is a non-conductive state is longer than a period during which the connection state between the pixel and the current source is a non-conductive state in the second operation mode. The driving method for a photoelectric conversion device according to any one of Methods 1 to 4.

[0144] (Method 6) A driving method for a photoelectric conversion device including a comparator that performs the comparison between the pixel signal and the threshold voltage, wherein a path for supplying a power supply voltage to the pixel is different from a path for supplying a power supply voltage to the comparator. The driving method for a photoelectric conversion device according to any one of Methods 1 to 5.

[0145] (Method 7) A driving method for a photoelectric conversion device including the pixel having a transistor electrically connectable to the output line, wherein the first driving is performed by turning off the transistor. The driving method for a photoelectric conversion device according to any one of Methods 1 to 6.

[0146] (Method 8) A driving method of a photoelectric conversion device including an output line having a switch disposed between the pixel and the current source, the method comprising performing the first driving by turning off the switch, the driving method of the photoelectric conversion device according to any one of Methods 1 to 7.

[0147] (Method 9) A driving method of a photoelectric conversion device including another output line that can be electrically connected to the current source and is different from the output line, the method comprising performing the first driving using the other output line after performing the first driving using the output line, the driving method of the photoelectric conversion device according to any one of Methods 1 to 8.

[0148] (Method 10) A driving method of a photoelectric conversion device including a pixel having a photoelectric conversion element that generates charges in response to incident light, a floating diffusion region, and a transfer transistor that transfers the charges to the floating diffusion region, an output line that can be electrically connected to the pixel and outputs a pixel signal based on the charges, and a speed-up circuit that can be electrically connected to the output line and speeds up the stabilization of the voltage value of the output line, the method comprising, at a first timing, turning on the transfer transistor to transfer the charges to the floating diffusion region, at a second timing, completing a comparison between the pixel signal based on the charges transferred to the floating diffusion region at the first timing and a threshold voltage, and between the first timing and the second timing, causing the output line to output the pixel signal with the operation of the speed-up circuit.

[0149] (Method 11) A driving method of a photoelectric conversion device including a comparator that performs the comparison between the pixel signal and the threshold voltage, the driving method of the photoelectric conversion device according to Method 10, wherein a path for supplying a power supply voltage to the pixel is different from a path for supplying a power supply voltage to the comparator.

[0150] (Method 12) A driving method of a photoelectric conversion device according to method 10 or 11, characterized in that a connection state between the speed-up circuit and the output line is changed from a non-conductive state to a conductive state between the first timing and the second timing.

[0151] (Method 13) The driving method of a photoelectric conversion device according to any one of methods 10 to 12, characterized in that the speed-up circuit has a current source electrically connectable to the output line and a switch disposed between the output line and the current source.

[0152] (Method 14) The driving method of a photoelectric conversion device according to any one of methods 10 to 13, characterized in that the speed-up circuit has a capacitive element electrically connectable to the output line and an amplifier disposed between the output line and the capacitive element.

[0153] (Method 15) A driving method of a photoelectric conversion device including a pixel having a photoelectric conversion element that generates charges according to incident light, a floating diffusion region, and a transfer transistor that transfers the charges to the floating diffusion region, an output line electrically connectable to the pixel and outputting a pixel signal based on the charges, and a limiting circuit electrically connectable to the output line and limiting a changeable range of a voltage of the output line. At a first timing, the transfer transistor is turned on and the charges are transferred to the floating diffusion region. At a second timing, a comparison between the pixel signal based on the charges transferred to the floating diffusion region at the first timing and a threshold voltage is completed. A driving method of a photoelectric conversion device is characterized in that a state of the limiting circuit is changed from a non-operating state to an operating state between the first timing and the second timing.

[0154] (Configuration 1) A photoelectric conversion device comprising a photoelectric conversion element that generates charges according to incident light, a floating diffusion region, and a transfer transistor that transfers the charges to the floating diffusion region, a pixel having the above components, an output line that is electrically connectable to the pixel and outputs a pixel signal based on the charges, a current source that is electrically connectable to the output line and supplies a current to the output line, and a control circuit that controls the connection state between the pixel and the current source. At a first timing, the transfer transistor is turned on and the charges are transferred to the floating diffusion region. At a second timing, a comparison between the pixel signal based on the charges transferred to the floating diffusion region at the first timing and a threshold voltage is completed. The control circuit performs a first drive to change the connection state between the pixel and the current source from a conductive state to a non-conductive state between the first timing and the second timing.

[0155] (Configuration 2) An apparatus comprising the photoelectric conversion device according to Configuration 1, further comprising at least one of an optical device that guides light to the photoelectric conversion device, a control device that controls the photoelectric conversion device, a processing device that processes a signal output from the photoelectric conversion device, a display device that displays information obtained by the photoelectric conversion device, a storage device that stores information obtained by the photoelectric conversion device, and a mechanical device that operates based on information obtained by the photoelectric conversion device.

Explanation of Reference Numerals

[0156] 100 Pixel 130 Output Line 135 Current Source 340 Control Circuit 400 Photoelectric Conversion Element 410 Transfer Transistor 420 Floating Diffusion Region

Claims

1. A pixel having a photoelectric conversion element that generates charge according to incident light, a floating diffusion region, and a transfer transistor that transfers the charge to the floating diffusion region, An output line that can be electrically connected to the pixel and outputs a pixel signal based on the charge, A current source that can be electrically connected to the output line and supplies a current to the output line, A driving method for a photoelectric conversion device including: At a first timing, the transfer transistor is turned on and the charge is transferred to the floating diffusion region, At a second timing, comparison between the pixel signal based on the charge transferred to the floating diffusion region at the first timing and a threshold voltage is completed, A first driving is performed to change a connection state between the pixel and the current source from a conductive state to a non-conductive state between the first timing and the second timing. A driving method for a photoelectric conversion device, characterized by the above.

2. At a third timing between the first timing and the second timing, the transfer transistor is turned off, and the first driving is performed between the first timing and the third timing. The driving method for a photoelectric conversion device according to Claim 1, characterized by the above.

3. After performing the first driving between the first timing and the second timing, a connection state between the pixel and the current source is changed from a non-conductive state to a conductive state between the first timing and the second timing. The driving method for a photoelectric conversion device according to Claim 1, characterized by the above.

4. A driving method for a photoelectric conversion device having a first operation mode in which a first current is supplied from the current source and a second operation mode in which a second current larger than the first current is supplied from the current source, In the first operation mode, a period during which the connection state between the pixel and the current source is non-conductive is longer than a period during which the connection state between the pixel and the current source is non-conductive in the second operation mode. The driving method for a photoelectric conversion device according to Claim 3, characterized by the above.

5. Comprising a plurality of comparators that can be electrically connected to the output line, A driving method for a photoelectric conversion device having a plurality of operation modes in which the number of the plurality of comparators electrically connected to the output line is different. In a first operation mode which is one of the plurality of modes, the number of the plurality of comparators electrically connected to the output line is larger than the number of the plurality of comparators electrically connected to the output line in a second operation mode which is one of the plurality of modes, and in the first operation mode, a period during which a connection state between the pixel and the current source is in a non-conductive state is longer than a period during which the connection state between the pixel and the current source is in a non-conductive state in the second operation mode. A driving method of a photoelectric conversion device according to claim 3, characterized in that.

6. A driving method of a photoelectric conversion device including a comparator that compares the pixel signal and the threshold voltage, A driving method of a photoelectric conversion device according to claim 1, characterized in that a path for supplying a power supply voltage to the pixel and a path for supplying a power supply voltage to the comparator are different.

7. A driving method of a photoelectric conversion device including the pixel having a transistor electrically connectable to the output line, A driving method of a photoelectric conversion device according to claim 1, characterized in that the first driving is performed by turning off the transistor.

8. A driving method of a photoelectric conversion device including the output line having a switch arranged between the pixel and the current source, A driving method of a photoelectric conversion device according to claim 1, characterized in that the first driving is performed by turning off the switch.

9. A driving method of a photoelectric conversion device including another output line that is electrically connectable to the current source and is different from the output line, A driving method of a photoelectric conversion device according to claim 1, characterized in that after performing the first driving using the output line, the first driving is performed using the other output line.

10. A pixel having a photoelectric conversion element that generates charges according to incident light, a floating diffusion region, and a transfer transistor that transfers the charges to the floating diffusion region, An output line that is electrically connectable to the pixel and outputs a pixel signal based on the charges, A high-speed circuit that is electrically connectable to the output line and speeds up the stabilization of the voltage value of the output line, A driving method of a photoelectric conversion device including: At a first timing, the transfer transistor is turned on and the charges are transferred to the floating diffusion region, At the second timing, the comparison between the pixel signal based on the charge transferred to the floating diffusion region at the first timing and the threshold voltage is completed, Between the first timing and the second timing, the output line outputs the pixel signal along with the operation of the speed-up circuit A method for driving a photoelectric conversion device, characterized by the above.

11. A method for driving a photoelectric conversion device including a comparator that performs the comparison between the pixel signal and the threshold voltage, The method for driving a photoelectric conversion device according to claim 10, characterized in that a path for supplying a power supply voltage to the pixel and a path for supplying a power supply voltage to the comparator are different.

12. The method for driving a photoelectric conversion device according to claim 10, characterized in that between the first timing and the second timing, the connection state between the speed-up circuit and the output line is changed from a non-conductive state to a conductive state.

13. The method for driving a photoelectric conversion device according to claim 12, characterized in that the speed-up circuit includes a current source electrically connectable to the output line and a switch arranged between the output line and the current source.

14. The method for driving a photoelectric conversion device according to claim 10, characterized in that the speed-up circuit includes a capacitive element electrically connectable to the output line and an amplifier arranged between the output line and the capacitive element.

15. A pixel having a photoelectric conversion element that generates charge in response to incident light, a floating diffusion region, and a transfer transistor that transfers the charge to the floating diffusion region, An output line electrically connectable to the pixel and outputting a pixel signal based on the charge, A limiting circuit electrically connectable to the output line and limiting a changeable range of the voltage of the output line, A method for driving a photoelectric conversion device including: At a first timing, the transfer transistor is turned on and the charge is transferred to the floating diffusion region, At a second timing, the comparison between the pixel signal based on the charge transferred to the floating diffusion region at the first timing and the threshold voltage is completed, Between the first timing and the second timing, the state of the limiting circuit is changed from a non-operating state to an operating state A method for driving a photoelectric conversion device, characterized by the above.

16. A pixel having a photoelectric conversion element that generates charge in response to incident light, a floating diffusion region, and a transfer transistor that transfers the charge to the floating diffusion region, An output line that can be electrically connected to the pixel and outputs a pixel signal based on the charge, A current source that can be electrically connected to the output line and supplies current to the output line, A control circuit that controls the connection state between the pixel and the current source, A photoelectric conversion device comprising: At a first timing, the transfer transistor is turned on and the charge is transferred to the floating diffusion region, At a second timing, a comparison between the pixel signal based on the charge transferred to the floating diffusion region at the first timing and a threshold voltage is completed, The control circuit performs a first drive to change the connection state between the pixel and the current source from a conductive state to a non-conductive state between the first timing and the second timing A photoelectric conversion device characterized by the above.

17. An apparatus comprising the photoelectric conversion device according to claim 16, An optical device that guides light to the photoelectric conversion device, A control device that controls the photoelectric conversion device, A processing device that processes a signal output from the photoelectric conversion device, A display device that displays information obtained by the photoelectric conversion device, A storage device that stores information obtained by the photoelectric conversion device, and An apparatus further comprising at least one of a mechanical device that operates based on information obtained by the photoelectric conversion device.

Images