Lamp Generator

Abstract

Reduces noise in the lamp signal. [Solution] An exemplary embodiment of the lamp generator 20 of this disclosure may include a pull-up current generation unit 210 that generates a pull-up current (PUC), a pull-down current generation unit 220 that generates a pull-down current (PDC), a variable resistor unit 230 whose one end is connected between the pull-up current generation unit 210 and the pull-down current generation unit 220, which outputs a lamp signal RS and to which a common voltage is applied, and a decoder unit 240 that controls the operation of the pull-up current generation unit 210 and the pull-down current generation unit 220.

Description

Technical Field

[0001] The technical idea of the present disclosure relates to a ramp generator that generates a ramp signal.

Background Art

[0002] An image sensing device is a device that captures an optical image using the property of a light-sensing semiconductor material that reacts to light. With the development of industries such as automobiles, medicine, computers, and communications, there is an increasing demand for high-performance image sensing devices in various fields such as smartphones, digital cameras, gaming devices, Internet of Things, robots, security cameras, and medical micro cameras.

[0003] An image sensing device may require a ramp generator that generates a ramp signal. Although the ramp signal may contain noise, it is necessary to reduce the noise of the ramp signal in order to improve the performance of the image sensing device.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The technical problem of the present disclosure aims to provide a ramp generator that reduces noise with respect to a ramp signal.

[0005] The technical problem of the present disclosure aims to provide a ramp generator that can change the noise distribution with respect to a ramp signal.

[0006] The technical problems to be achieved in the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by those with ordinary knowledge in the technical field to which the present disclosure belongs from the following description.

Means for Solving the Problems

[0007] An exemplary lamp generator according to the present disclosure may include a pull-up current generator that generates a pull-up current, a pull-down current generator that generates a pull-down current, a variable resistor unit whose one end is connected between the pull-up current generator and the pull-down current generator to output a lamp signal and to which a common voltage is applied, and a decoder unit that controls the operation of the pull-up current generator and the pull-down current generator.

[0008] According to one embodiment, the pull-up current generation unit includes pull-up current cells, and the pull-down current generation unit may include pull-down current cells.

[0009] According to one embodiment, the decoder unit can turn on at least a portion of the pull-up current cells, and then sequentially turn off the pull-up current cells that have been turned on.

[0010] According to one embodiment, when all pull-up current cells are turned off, the decoder unit can sequentially turn on at least some of the pull-down current cells.

[0011] According to one embodiment, the decoder unit can control the operation of the pull-up current generation unit and the pull-down current generation unit based on the noise distribution with respect to the lamp signal.

[0012] According to one embodiment, the decoder unit can reduce the number of pull-up current cells that are turned on as the size of the first noise required relative to the start of the lamp signal decreases.

[0013] According to one embodiment, the decoder unit can increase the number of pull-up current cells that are turned on as the size of the second noise required relative to the end of the lamp signal decreases.

[0014] According to one embodiment, the decoder unit can control the pull-up current generation unit and the pull-down current generation unit so that the number of pull-up current cells that are turned on and the number of pull-down current cells that are turned on are the same when the size of the third noise required for the midpoint between the start and end points of the ramp signal is smallest.

[0015] According to one embodiment, a power supply voltage can be applied to the pull-up current generation unit, and a ground voltage can be applied to the pull-down current generation unit.

[0016] According to one embodiment, the variable resistor section can have a resistance value that changes according to the required gain of the image sensing device.

[0017] According to one embodiment, the variable resistor can have a smaller resistance value as the required gain size increases.

[0018] An exemplary lamp generator according to the present disclosure may include pull-up current cells to which a power supply voltage is applied, pull-down current cells to which a ground voltage is applied, a variable resistor to which one end is connected between the pull-up and pull-down current cells to output a lamp signal and to which a common voltage is applied, and a decoder connected to the pull-up and pull-down current cells.

[0019] According to one embodiment, the decoder can turn on at least a portion of the pull-up current cells, and then sequentially turn off the pull-up current cells that have been turned on.

[0020] According to one embodiment, when all pull-up current cells are turned off, the decoder can sequentially turn on at least some of the pull-down current cells.

[0021] According to one embodiment, the decoder can control the operation of pull-up current cells and pull-down current cells based on the noise distribution to the ramp signal.

[0022] According to one embodiment, the decoder can reduce the number of pull-up current cells that are turned on as the size of the first noise required relative to the start of the ramp signal decreases.

[0023] According to one embodiment, the decoder can increase the number of pull-up current cells that are turned on as the size of the second noise required relative to the end of the ramp signal decreases.

[0024] According to one embodiment, the decoder can be controlled so that the number of pull-up current cells that are turned on and the number of pull-down current cells that are turned on are the same when the size of the third noise required for the midpoint between the start and end points of the ramp signal is smallest.

[0025] According to one embodiment, the variable resistor may have a resistance value that changes according to the required gain of the image sensing device.

[0026] A lamp generator according to an exemplary embodiment of the present disclosure may include pull-up current cells to which a power supply voltage is applied, pull-down current cells to which a ground voltage is applied, a variable resistor having one end where a lamp signal is output and the other end to which a common voltage is applied, and the resistance value of which is determined based on the number of pull-up current cells and pull-down current cells that are turned on, and a decoder that controls the operations of the pull-up current cells and the pull-down current cells.

[0027] The features briefly summarized above regarding the present disclosure are exemplary aspects of the detailed description of the present disclosure to be described later, and do not limit the scope of the present disclosure.

Advantages of the Invention

[0028] A lamp generator according to an exemplary embodiment of the present disclosure can reduce noise with respect to a lamp signal.

[0029] A lamp generator according to an exemplary embodiment of the present disclosure can change the noise distribution with respect to a lamp signal.

[0030] The effects obtained in the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those with ordinary knowledge in the technical field to which the present disclosure belongs from the following description.

Brief Description of the Drawings

[0031] [Figure 1] It is a block diagram regarding an imaging device according to an exemplary embodiment of the present disclosure. [Figure 2] It is a block diagram showing a lamp generator according to an exemplary embodiment of the present disclosure. [Figure 3] It is a diagram showing a lamp generator according to an exemplary embodiment of the present disclosure. [Figure 4]This figure shows a ramp signal according to an exemplary embodiment of the present disclosure. [Figure 5] This figure illustrates the operation of a lamp generator according to an exemplary embodiment of the present disclosure. [Figure 6] This diagram illustrates the noise distribution of a ramp signal using a comparative example. [Figure 7] This figure illustrates the noise distribution of a ramp signal according to an exemplary embodiment of the present disclosure. [Figure 8] This figure illustrates the noise distribution of a ramp signal according to an exemplary embodiment of the present disclosure. [Modes for carrying out the invention]

[0032] The embodiments of this disclosure will be described in detail below with reference to the accompanying drawings, so that they can be easily implemented by a person skilled in the art to which this disclosure pertains. However, this disclosure can be implemented in a variety of different forms and is not limited to the embodiments described herein.

[0033] In describing embodiments of this disclosure, if it is determined that a specific description of a known configuration or technology would obscure the gist of this disclosure, such detailed description will be omitted. Furthermore, in the drawings, parts unrelated to the description of this disclosure will be omitted, and similar parts will be denoted by similar reference numerals.

[0034] In this disclosure, when we say that one component is “connected,” “joined,” or “linked” to another component, this can include not only direct connections but also indirect connections where other components exist in between. Furthermore, when we say that one component “includes” or “has” another component, this means, unless otherwise stated to the contrary, that it may include even more components rather than excluding them.

[0035] In this disclosure, terms such as "first," "second," etc., are used solely for the purpose of distinguishing one component from another, and do not limit the order or importance of the components unless otherwise specified. Accordingly, within the scope of this disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and similarly, a second component in one embodiment may be referred to as a first component in another embodiment.

[0036] In this disclosure, components that are distinguished from each other are used to clearly describe their respective characteristics and do not necessarily imply that the components are separate. That is, multiple components may be integrated to form a single hardware or software unit, or a single component may be distributed to form multiple hardware or software units. Accordingly, such integrated or distributed embodiments are also included in the scope of this disclosure, without needing to be specifically mentioned.

[0037] In this disclosure, the components described in various embodiments are not necessarily essential components, and some may be optional components. Therefore, embodiments consisting of a subset of the components described in one embodiment are also included in the scope of this disclosure. Furthermore, embodiments that include other components in addition to the components described in various embodiments are also included in the scope of this disclosure.

[0038] In this disclosure, the terms used herein to describe positional relationships, such as top, bottom, left, and right, are provided for explanatory purposes only. If the drawings shown herein are viewed in reverse, the positional relationships described in the specification may be interpreted in the opposite way.

[0039] In this disclosure, each phrase such as “A or B,” “at least one of A and B,” “at least one of A or B,” “A, B or C,” “at least one of A, B and C,” and “at least one of A, B, or C” may include any one of the items listed together with the phrase, or any possible combination thereof.

[0040] Hereinafter, exemplary embodiments of this disclosure will be specifically described with reference to Figures 1 to 8.

[0041] Figure 1 is a block diagram showing an imaging apparatus according to one embodiment of the present disclosure.

[0042] Referring to Figure 1, the imaging device 10 may refer to a device such as a digital still camera for capturing still images or a digital video camera for capturing moving images. For example, the imaging device 10 can be implemented as a digital single-lens reflex (DSLR), a mirrorless camera, or a smartphone, but is not limited to these. The imaging device 10 may also be a concept that includes an image sensor capable of capturing a subject and generating an image.

[0043] The imaging device 10 may include an image sensing device 100 and an image signal processor (ISP) 200.

[0044] The image sensing device 100 may be a CIS (Complementary Metal Oxide Semiconductor Image Sensor) that converts incident light into electrical signals. The image sensing device 100 may include a pixel array 110, a row driver 120, a ramp generator 130, an analog-to-digital converter (ADC) 140, an output buffer 150, a column driver 160, and a timing controller 170. Here, each component of the image sensing device 100 is illustrative, and at least some components may be added or omitted as needed.

[0045] The pixel array 110 may include a plurality of pixels arranged in a plurality of rows and a plurality of columns. In one embodiment, the plurality of pixels may be arranged in a two-dimensional pixel array including rows and columns. In another embodiment, the plurality of unit image pixels may be arranged in a three-dimensional pixel array. The plurality of pixels can convert optical signals into electrical signals on a pixel-by-pixel or pixel-group basis, and pixels within a pixel group may share at least one internal circuit. The pixel array 110 may receive drive signals DS1 from the row control circuit 120, including a row selection signal, a pixel reset signal, and a transfer signal, and the drive signals DS1 may activate the pixels of the pixel array 110 to perform operations corresponding to the row selection signal, the pixel reset signal, and the transfer signal.

[0046] Each pixel in the pixel array 110 may have a sensitivity of at least two different values ​​from each other. Here, sensitivity may mean the increase in image data IDATA (or the increase in response) in response to an increase in the intensity of incident light. That is, the higher the sensitivity, the greater the increase in image data IDATA in response to an increase in the intensity of incident light, and the lower the sensitivity, the smaller the increase in image data IDATA in response to an increase in the intensity of incident light. In this disclosure, sensitivity may be determined by the conversion gain.

[0047] The row driver 120 can activate the pixel array 110 to perform a specific operation on the pixels contained in the row, based on commands and / or control signals TS1 supplied by the timing controller 170. In one embodiment, the row driver 120 can select at least one pixel arranged in at least one row of the pixel array 110. The row driver 120 can generate a row selection signal to select at least one row from a plurality of rows. The row driver 120 can sequentially enable a pixel reset signal and a transfer signal for the pixels corresponding to the selected row. This allows analog reference signals and video signals generated from each pixel in the selected row to be sequentially transmitted to the ADC 140. Here, the reference signal is an electrical signal provided to the ADC 140 when the sensing node (e.g., floating diffusion region) of the pixel is reset, and the video signal may be an electrical signal provided to the ADC 140 when photocharge generated by the pixel is accumulated in the sensing node. A reference signal indicating pixel-specific reset noise and a video signal indicating the intensity of incident light can be referred to as a pixel signal (PS).

[0048] CMOS image sensors can utilize Correlated Double Sampling (CDS) to remove unwanted offset values ​​of pixels, such as fixed pattern noise, by sampling the pixel signal twice to eliminate the difference between two samples. For example, Correlated Double Sampling can remove unwanted offset values ​​by comparing the pixel output voltage acquired before and after the photocharge generated by the incident light is accumulated in the sensing node, thereby measuring only the pixel output voltage based on the incident light. In one embodiment, the ADC 140 can sequentially sample and hold reference signals and image signals provided from each of several column lines of the pixel array 110.

[0049] The ramp generator 130 can generate the ramp signal RS necessary for the analog-to-digital conversion operation of the ADC 140 based on the timing signal TS2 of the timing controller 170, and supply it to the ADC 140.

[0050] The ADC140 can sample and hold the pixel signal for each column output from each column line of the pixel array 110 based on the timing signal TS3 of the timing controller 170, convert it to a digital signal, and output it. In one embodiment, the ADC140 can be implemented as a ramp-compare type ADC. The ramp-compare type ADC may include a comparator circuit that compares a ramp signal that rises or falls over time with the analog form of the pixel signal, and a counter that performs counting operations until the ramp signal matches the analog pixel signal.

[0051] The output buffer 150 can temporarily hold and output the image data (i.e., data obtained by digitally converting pixel signals; IDATA) for each column provided by the ADC 140. The output buffer 150 can temporarily store the image data IDATA output from the ADC 140 based on the timing signal TS4 of the timing controller 170. The output buffer 150 can operate as an interface to compensate for differences in transfer (or processing) speeds between the image sensing device 100 and other devices connected to it.

[0052] The column driver 160 can select a column in the output buffer 150 based on the timing signal TS5 of the timing controller 170, and control the output buffer 150 so that the image data IDATA temporarily stored in the selected column of the output buffer 150 is output sequentially. In one embodiment, the column driver 160 can receive an address signal from the timing controller 170, and the column driver 160 can generate a column selection signal CSS based on the address signal and select a column in the output buffer 150, thereby controlling the output buffer 150 so that the image data IDATA is output externally from the selected column.

[0053] The timing controller 170 can control at least one of the following: the low driver 120, the ramp generator 130, the ADC 140, the output buffer 150, and the column driver 160.

[0054] The timing controller 170 can provide clock signals required for the operation of each component of the image sensing device 100, control signals for timing control, and address signals for selecting a low or column to at least one of the low driver 120, ramp generator 130, ADC 140, output buffer 150, and column driver 160. In one embodiment, the timing controller 170 may include a logic control circuit, a phase lock loop (PLL) circuit, a timing control circuit, and a communication interface circuit.

[0055] The ISP200 can perform video signal processing on image data IDATA received from the image sensing device 100. The ISP200 can reduce noise in the image data IDATA and perform image signal processing for image quality improvement, such as interpolation, synthesis, gamma correction, color filter array interpolation, color matrix, color correction, color enhancement, and lens distortion correction. Furthermore, the ISP200 can compress the image data generated by the image signal processing for image quality improvement to produce a video file, or repair the image data from the video file. The video compression format may be lossless or lossy. Examples of compression formats include JPEG (Joint Photographic Experts Group) and JPEG2000 for still images. For moving images, a video file can be generated by compressing multiple frames according to the MPEG (Moving Picture Experts Group) standard. Video files can be generated, for example, according to the Exif (Exchangeable image file format) standard.

[0056] The ISP200 can generate an HDR image by combining at least two images with different sensitivities. For example, the image sensing device 100 can output a low-sensitivity image generated from relatively low-sensitivity pixels (low-conversion-gain pixels) and a high-sensitivity image generated from relatively high-sensitivity pixels (high-conversion-gain pixels), and the ISP200 can generate an HDR image by combining the low-sensitivity image and the high-sensitivity image. Here, low sensitivity and high sensitivity are relative concepts, and the image sensing device 100 can generate n (where n is a constant of 2 or more) or more video data IDATA with different sensitivities, and the image signal processor 200 can use these to generate an HDR image.

[0057] The ISP200 can transfer the image data after the image processing operation is complete to a host device (not shown). The host device (not shown) may be a processor (e.g., an application processor) that processes the image processed image data received from the ISP200, a memory (e.g., non-volatile memory) that stores the image data, or a display device (e.g., an LCD (Liquid Crystal Display)) that visually outputs the image data.

[0058] Furthermore, the ISP200 can transfer control signals to the image sensing device 100 to control its operation (such as whether it is operating, the timing of operation, and the mode of operation).

[0059] Figure 2 is a block diagram showing a lamp generator according to an exemplary embodiment of the present disclosure.

[0060] Referring to Figure 2, the lamp generator 20 according to an exemplary embodiment of the present disclosure may include a pull-up current generation unit 210, a pull-down current generation unit 220, a variable resistor unit 230, and a decoder unit 240.

[0061] The pull-up current generation unit 210 can generate a pull-up current (PUC). For example, the pull-up current generation unit 210 can generate a pull-up current (PUC) by including pull-up current cells. For example, a pull-up current (PUC) can be generated when at least a portion of the pull-up current cells of the pull-up current generation unit 210 are turned on. Alternatively, the size of the pull-up current (PUC) can be gradually reduced as the turned-on pull-up current cells of the pull-up current generation unit 210 are sequentially turned off.

[0062] The pull-down current generation unit 220 can generate a pull-down current PDC. For example, the pull-down current generation unit 220 can generate a pull-down current PDC by including pull-down current cells. For example, a pull-down current PDC can be generated by at least some of the pull-down current cells of the pull-down current generation unit 220 being turned on sequentially. Furthermore, the size of the pull-down current PDC can gradually increase as the turn-off pull-down current cells of the pull-down current generation unit 220 are turned on sequentially.

[0063] The variable resistor section 230 may include a variable resistor. The variable resistor section 230 may also be connected between the pull-up current generation section 210 and the pull-down current generation section 220. Furthermore, the variable resistor section 230 may output a ramp signal RS. A common voltage may also be applied to the variable resistor section 230. The resistance value of the variable resistor section 230 can be changed according to the gain of the image sensing device. For example, the larger the required gain, the smaller the resistance value of the variable resistor section 230 can be, but this is not limited to that. The resistance value of the variable resistor section 230 can also be changed based on the number of pull-up and pull-down current cells that are turned on. For example, the larger the total number of pull-up and pull-down current cells that are turned on, the smaller the resistance value of the variable resistor section 230 can be, but this is not limited to that.

[0064] The decoder unit 240 can control the operation of the pull-up current generation unit 210 and the pull-down current generation unit 220. For example, the decoder unit 240 can control the operation of the pull-up current generation unit 210 and the pull-down current generation unit 220 by transmitting a decoder signal D1 to the pull-up current generation unit 210 and a decoder signal D2 to the pull-down current generation unit 220. Specifically, the decoder unit 240 can turn on at least some of the pull-up current cells and then sequentially turn off the turned-on pull-up current cells. Also, if all the pull-up current cells have been turned off, the decoder unit 240 can sequentially turn on at least some of the pull-down current cells.

[0065] The decoder unit 240 can control the operation of the pull-up current generation unit 210 and the pull-down current generation unit 220 based on the noise distribution with respect to the ramp signal RS. For example, the decoder unit 240 can reduce the number of pull-up current cells turned on as the size of the first noise required for the start of the ramp signal RS is smaller. Also, the decoder unit 240 can increase the number of pull-up current cells turned on as the size of the second noise required for the end of the ramp signal RS is smaller. Furthermore, when the size of the third noise required for an intermediate point between the start and end of the ramp signal RS is smallest, the decoder unit 240 can control the pull-up current generation unit 210 and the pull-down current generation unit 220 so that the number of pull-up current cells turned on and the number of pull-down current cells turned on are the same. More specific details of how the decoder unit 240 controls the pull-up current generation unit 210 and the pull-down current generation unit 220 will be described later.

[0066] Figure 3 shows a lamp generator according to an exemplary embodiment of the present disclosure.

[0067] Figure 4 shows a ramp signal according to an exemplary embodiment of the present disclosure.

[0068] Figure 5 is a diagram illustrating the operation of a lamp generator according to an exemplary embodiment of the present disclosure.

[0069] Figure 3 can be explained below with reference to Figures 4 and 5.

[0070] Referring to Figure 3, the lamp generator 300 according to an exemplary embodiment of the present disclosure may include a pull-up current cell 310, a pull-down current cell 320, and a variable resistor 330.

[0071] A power supply voltage can be applied to the pull-up current cell 310.

[0072] A ground voltage can be applied to the pull-down current cell 320.

[0073] One end of the variable resistor 330 can be connected to a pull-up current cell 310 and a pull-down current cell 320, allowing it to output a ramp signal Vramp. The other end of the variable resistor 330 can be connected to a common voltage VCOM.

[0074] Referring to Figure 4, when the pull-up current cell 310 connected to the power supply voltage is turned on, the voltage size of the ramp signal Vramp can rise to above the common voltage VCOM, as shown at time t1. For the sake of explanation, time t1 can be referred to as the start time of the ramp signal Vramp. The rising voltage size can be proportional to the number of pull-up current cells 310 that are turned on. For example, referring to Figure 5(a), if the resistance value of the variable resistor is R, the size of the current generated by each pull-up current cell is I, and N pull-up current cells are turned on, the voltage size of the ramp signal Vramp can be VCOM + N * I * R.

[0075] Furthermore, the pull-up current cells 310, which were turned on at time t2, are turned off one by one in sequence, allowing the voltage size of the ramp signal Vramp to gradually decrease.

[0076] At time t3, when all pull-up current cells 310 have turned off, the voltage size of the ramp signal Vramp may be the same as the common voltage VCOM. At time t3, when all pull-up current cells 310 have turned off, the pull-down current cells 320 to which the ground voltage is applied can be turned on one by one in sequence. As the number of pull-down current cells 320 that are turned on increases, the voltage size of the ramp signal Vramp can be gradually reduced.

[0077] For the sake of explanation, the point in time when a determined number of pull-down current cells 320 have been turned on can be referred to as the point in time when the ramp signal Vramp ends, and this corresponds to time t4 in Figure 4. Referring to Figure 5(b), if we assume that the current size of each pull-down current cell is I and that N pull-down current cells 320 have been turned on, the voltage size of the ramp signal Vramp at time t4 may be VCOM-N*I*R.

[0078] Next, all the pull-down current cells 320 turn off and the pull-up current cells 310 turn on, so that a ramp signal Vramp with an increased voltage size, as at time t1, can be output.

[0079] The gradient and voltage magnitude of the ramp signal Vramp can be determined according to the resistance value of the variable resistor 330. Furthermore, the resistance value of the variable resistor 330 can be determined by the gain of the image sensing device. For example, referring to Figure 4, if a high gain is required for the image sensing device, the resistance value of the variable resistor 330 may be larger than when a low gain is required.

[0080] Figure 6 is a diagram illustrating the noise distribution of the ramp signal in a comparative example.

[0081] Referring to Figure 6(a), the comparative example lamp generator 600 may include a pull-up current cell 610, a resistor 620, and a decoder 630. One end of the resistor 620 can be connected to the pull-up current cell 610, and the other end can be to which a ground voltage VSS can be applied. The lamp generator 600 can turn on the pull-up current cell 610 to generate the lamp signal Vramp'. The lamp generator 600 can also create a gradient of the lamp signal Vramp' by turning off the turned-on pull-up current cells 610 one by one until all of the pull-up current cells 610 are turned off. The noise of the lamp signal Vramp' of the lamp generator 600 can be generated by the pull-up current cells 610, and therefore can be proportional to the number of pull-up current cells 610 that are turned on. Therefore, referring to Figure 6(b), the noise in section 670 for the lamp signal Vramp' may be smaller than the noise in section 660. Furthermore, the noise in section 660 for the ramp signal Vramp' may be less than the noise in section 650. Also, the noise in section 650 for the ramp signal Vramp' may be less than the noise in section 640.

[0082] Figure 7 is a diagram illustrating the noise distribution of a ramp signal according to an exemplary embodiment of the present disclosure.

[0083] Figure 7 can be explained below with reference to Figures 3 and 6.

[0084] The lamp generator 300 in Figure 3 can generate a lamp signal Vramp that corresponds to the lamp signal Vramp' generated by the lamp generator 600 in Figure 6. For example, assuming that the current size generated by the current cells in the lamp generator 300 and the lamp generator 600 are the same, and the resistance values ​​of the resistors are the same, and that the lamp generator 600 turns on a total of 1500 pull-up current cells 610 to generate the lamp signal Vramp', and then turns off the 1500 turned-on pull-up current cells 610 one by one in sequence, the lamp generator 300 can generate the lamp signal Vramp by turning on 750 pull-up current cells 310 and 750 pull-down current cells 320. Specifically, the ramp generator 300 turns on 750 pull-up current cells 310, then turns off the 750 pull-up current cells 310 one by one, and once all the pull-up current cells 310 are turned off, it can turn on the pull-down current cells 320 one by one up to a total of 750. Because the number of current cells turned on differs between the ramp generator 300 and the ramp generator 600, the noise distributions of the ramp signal Vramp and the ramp signal Vramp' can differ from each other. Specifically, referring to Figure 7, with 750 pull-up current cells 310 turned on and 750 pull-down current cells 320 turned on, a symmetrical noise distribution can be obtained with respect to the common voltage VCOM. That is, the noise in section 720 and the noise in section 730 can correspond to each other, and the noise in section 710 and the noise in section 740 can correspond to each other. Furthermore, since the pull-up current cells 610 of the lamp generator 600 need to have a total of 1500 cells turned on, the maximum noise size of the lamp generator 600 can be larger than that of the lamp generator 300, which has only 750 current cells turned on.In other words, the ramp generator 300 includes a variable resistor 330 to which a common voltage is applied, and by including a pull-up current cell 310 and a pull-down current cell 320, the number of current cells that need to be turned on simultaneously can be reduced, thereby reducing the noise size of the ramp signal Vramp. The above figures are illustrative for the sake of explanation, and exemplary embodiments of the present disclosure are not limited to those described above.

[0085] Figure 8 is a diagram illustrating the noise distribution of a ramp signal according to an exemplary embodiment of the present disclosure.

[0086] Figure 8 can be explained below with reference to Figure 3.

[0087] Referring to Figure 3, the lamp generator 300 according to an exemplary embodiment of the present disclosure can adjust the number of current cells to be turned on and turned off according to the control of the decoder 340. For example, the decoder 340 can decide whether or not to turn on the pull-up current cell 310 and the pull-down current cell 320 based on the noise distribution to the lamp signal Vramp.

[0088] For example, assuming that the lamp generator 300 generates a lamp signal Vramp using a total of M current cells, the decoder 340 can turn on N pull-up current cells 310, and then MN pull-down current cells 320. Depending on the number N of pull-up current cells 310 turned on by the decoder 340, the noise distribution for the lamp signal Vramp may differ. Assuming that the lamp generator 300 generates a lamp signal Vramp using a total of 1500 current cells (M=1500), Figure 8(a) may be a graph of the lamp signal Vramp when 750 pull-up current cells 310 and 750 pull-down current cells 320 are turned on (N=750). Also, Figure 8(b) may be a graph of the lamp signal Vramp when 375 pull-up current cells 310 and 1125 pull-down current cells 320 are turned on (N=375). Since the number of current cells that turn on differs in each section of Figure 8(a) and (b), the ramp signals Vramp in Figure 8(a) and (b) can have different noise distributions. For example, in section 810, more pull-up current cells 310 turn on than in section 850, so the noise size of the ramp signal Vramp in section 810 can be larger than the noise size in section 850. Also, since the number of pull-up current cells 310 that turn on in section 820 is vertically symmetrical with the number of pull-down current cells 320 that turn on in section 860, the noise of the ramp signal Vramp can also be vertically symmetrical. Furthermore, since the number of pull-down current cells 320 that turn on in section 830 is less than the number of pull-down current cells 320 that turn on in section 870, the noise size of the ramp signal Vramp in section 830 may be smaller than the noise size in section 870. Furthermore, since the number of pull-down current cells 320 that turn on in section 840 is less than the number of pull-down current cells 320 that turn on in section 880, the noise size of the ramp signal Vramp in section 840 may be smaller than the noise size in section 880.Overall, the noise size of the ramp signal Vramp may be highest in section 880, where the most current cells are turned on, and lowest in sections 820, 830, 850, and 860, where the fewest current cells are turned on. In other words, the ramp generator 300 according to an exemplary embodiment of the present disclosure can adjust the number of current cells turned on according to the desired noise distribution of the ramp signal. The above figures are illustrative for convenience of explanation, and exemplary embodiments of the present disclosure are not limited to those described above.

[0089] The above description is merely illustrative of the technical concept of the Disclosure, and any person with ordinary skill in the art to which the Disclosure pertains can make various modifications and variations without departing from the essential characteristics of the Disclosure. Therefore, the embodiments disclosed herein are for illustrative purposes only, and not to limit the technical concept of the Disclosure, and such embodiments do not limit the scope of the technical concept of the Disclosure. The scope of protection of the Disclosure shall be construed in accordance with the following claims, and all technical concepts within an equivalent scope shall be construed as being included within the scope of the Disclosure. [Explanation of symbols]

[0090] 10. Imaging device 20 Lamp Generators 100 Image Sensing Devices 110 pixel array 120 Low Driver 130 Lamp generator 150 Output buffer 160 Column Driver 170 Timing controller 200 Image Signal Processors 210 Pull-up current generation section 220 Pull-down current generation unit 230 Variable resistor section 240 Decoder section 300 Lamp Generator 310 Pull-up Current Cell 320 Pull-Down Current Cells 330 Variable resistor 340 Decoders 600 Lamp Generator 610 Pull-up Current Cell 620 resistors 630 Decoder

Claims

1. A pull-up current generation unit that generates a pull-up current, A pull-down current generation unit that generates a pull-down current, A variable resistor unit, one end of which is connected between the pull-up current generation unit and the pull-down current generation unit, outputs a ramp signal, and to which a common voltage is applied at the other end, A lamp generator including a decoder unit that controls the operation of the pull-up current generation unit and the pull-down current generation unit.

2. The pull-up current generation unit is, Includes pull-up current cells, The aforementioned pull-down current generation unit is A lamp generator according to claim 1, comprising pull-down current cells.

3. The decoder unit is The lamp generator according to claim 2, wherein at least a portion of the pull-up current cells are turned on, and then the turned-on pull-up current cells are turned off sequentially.

4. The decoder unit is The lamp generator according to claim 3, wherein when all of the pull-up current cells are turned off, at least some of the pull-down current cells are turned on sequentially.

5. The decoder unit is The lamp generator according to claim 2, wherein the operation of the pull-up current generation unit and the pull-down current generation unit is controlled based on the noise distribution to the lamp signal.

6. The decoder unit is The lamp generator according to claim 5, wherein the smaller the size of the first noise required relative to the start time of the lamp signal, the fewer the number of pull-up current cells that are turned on.

7. The decoder unit is The lamp generator according to claim 5, wherein the smaller the size of the second noise required for the termination of the lamp signal, the more the number of pull-up current cells that are turned on is increased.

8. The decoder unit is The lamp generator according to claim 5, wherein the pull-up current generation unit and the pull-down current generation unit are controlled such that the number of pull-up current cells that are turned on is the same as the number of pull-down current cells that are turned on when the size of the third noise required for the midpoint between the start and end points of the lamp signal is smallest.

9. The pull-up current generation unit includes: When the power supply voltage is applied, The pull-down current generation unit includes: A lamp generator according to claim 1, wherein a ground voltage is applied.

10. The aforementioned variable resistor section is The lamp generator according to claim 1, having a resistance value that changes according to the required gain of the image sensing device.

11. The aforementioned variable resistor section is The lamp generator according to claim 10, wherein the resistance value decreases as the size of the required gain increases.

12. Pull-up current cells to which the power supply voltage is applied, Pull-down current cells to which the ground voltage is applied, A variable resistor, one end of which is connected between the pull-up current cell and the pull-down current cell, outputs a ramp signal, and to which a common voltage is applied at the other end, A lamp generator including a decoder connected to the pull-up current cell and the pull-down current cell.

13. The decoder mentioned above is The lamp generator according to claim 12, wherein at least a portion of the pull-up current cells are turned on, and then the turned-on pull-up current cells are turned off sequentially.

14. The decoder mentioned above is The lamp generator according to claim 13, wherein when all of the pull-up current cells are turned off, at least some of the pull-down current cells are turned on sequentially.

15. The decoder mentioned above is The lamp generator according to claim 12, which controls the operation of the pull-up current cell and the pull-down current cell based on the noise distribution to the lamp signal.

16. The decoder mentioned above is The lamp generator according to claim 15, wherein the smaller the size of the first noise required relative to the start time of the lamp signal, the fewer the number of pull-up current cells that are turned on.

17. The decoder mentioned above is The lamp generator according to claim 15, wherein the smaller the size of the second noise required for the termination of the lamp signal, the more the number of pull-up current cells that are turned on is increased.

18. The decoder mentioned above is The lamp generator according to claim 15, wherein when the size of the third noise obtained for the midpoint between the start and end points of the lamp signal is smallest, the number of pull-up current cells that are turned on and the number of pull-down current cells that are turned on are controlled to be the same.

19. The aforementioned variable resistor is The lamp generator according to claim 12, having a resistance value that changes according to the required gain of the image sensing device.

20. Pull-up current cells to which the power supply voltage is applied, Pull-down current cells to which the ground voltage is applied, A variable resistor whose resistance value is determined based on the number of pull-up and pull-down current cells that are turned on when a ramp signal is output from one end and a common voltage is applied to the other end, A lamp generator including a decoder that controls the operation of the pull-up current cell and the pull-down current cell.

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