Imaging device

Abstract

This reduces the total amount of current flowing through the flexible circuit board, thereby suppressing image quality degradation. [Solution] The system comprises an imaging board on which an imaging sensor is mounted, a main board that supplies power to the imaging board, and a flexible circuit board that connects the main board and the imaging board. The main board supplies a first voltage higher than the operating voltage of the imaging sensor to the imaging board via the flexible circuit board. The imaging board has a step-down circuit that converts the first voltage to a second voltage lower than the first voltage and outputs it to the imaging sensor. The step-down circuit includes a switched capacitor that steps down the voltage supplied from the main board to 1 / N (where N is a natural number), and a DC-DC converter including an inductor connected to the switched capacitor.

Description

Technical Field

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[0001] The present invention relates to a power supply technology for an imaging sensor in an imaging device.

Background Art

[0002] In conventional imaging devices such as single-lens reflex cameras and mirrorless cameras, a DC-DC converter that supplies power to an imaging sensor is used. In order to reduce the influence of magnetic noise on the image due to the magnetic noise generated when the DC-DC converter operates, in a conventional imaging device, the DC-DC converter is arranged on a board different from the imaging board on which the imaging sensor is mounted.

[0003] In recent years, there are also imaging devices with an image blur correction function by physically moving the imaging board. In order not to hinder the movement of the imaging board, it is desirable that the flexible circuit board connected to the imaging board is provided with a long extra length, the wiring width is made as thin as possible, and the thickness is also made thin.

[0004] On the other hand, in recent years, with the increase in the readout speed and pixel count of imaging sensors, the current flowing through the flexible circuit board tends to increase. An increase in the current flowing through the flexible circuit board causes problems such as deterioration of image quality due to an increase in magnetic radiation. In addition, an increase in current and an increase in the amount of heat generated due to wiring resistance and the like also cause image quality deterioration.

[0005] In Patent Document 1, as a method of supplying power to an imaging sensor, a method of suppressing the current of the first power supply circuit by providing a second power supply circuit in addition to the first power supply circuit is described.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

[0007] However, the prior art disclosed in Patent Document 1 cannot reduce the total amount of current flowing through the flexible substrate.

[0008] This invention has been made in view of the above-mentioned problems, and its purpose is to reduce the total amount of current flowing through a flexible circuit board and suppress the deterioration of image quality. [Means for solving the problem]

[0009] The imaging device according to the present invention comprises an imaging substrate on which an imaging sensor is mounted, a main substrate that supplies power to the imaging substrate, and a flexible circuit board that connects the main substrate and the imaging substrate, wherein the main substrate supplies a first voltage higher than the voltage at which the imaging sensor operates to the imaging substrate via the flexible circuit board, and the imaging substrate has a step-down circuit that converts the first voltage to a second voltage lower than the first voltage and outputs it to the imaging sensor, wherein the step-down circuit comprises a switched capacitor that steps down the voltage supplied from the main substrate to 1 / N (where N is a natural number), and a DC-DC converter including an inductor connected to the switched capacitor. [Effects of the Invention]

[0010] According to the present invention, it is possible to reduce the total amount of current flowing through the flexible circuit board and suppress the deterioration of image quality. [Brief explanation of the drawing]

[0011] [Figure 1] A block diagram showing the configuration of an imaging device according to a first embodiment of the present invention. [Figure 2] A diagram showing the implementation configuration of the imaging device. [Figure 3] A diagram showing an example of the circuit configuration of the imaging power supply unit and its surroundings. [Figure 4]A diagram showing another example of the circuit configuration of the imaging power supply unit and its surroundings. [Figure 5] A flowchart showing the control details of the imaging power supply unit. [Figure 6] A diagram showing another example of the circuit configuration of the imaging power supply unit and its surroundings. [Figure 7] A diagram showing another example of the circuit configuration of the imaging power supply unit and its surroundings. [Figure 8] A flowchart showing the control details of the imaging power supply unit. [Figure 9] Figure 2 shows the layout of the components of the imaging power supply unit placed on the imaging substrate. [Figure 10] A diagram showing the implementation configuration of the imaging device in the second embodiment. [Figure 11] Figure 10 shows the layout of the components of the imaging power supply unit that are arranged on the imaging power supply board. [Modes for carrying out the invention]

[0012] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention as defined in the claims. While the embodiments describe multiple features, not all of these features are essential to the invention, and the features may be combined in any way. Furthermore, in the attached drawings, identical or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0013] (First embodiment) Figure 1 is a block diagram showing the configuration of an imaging device 100 according to a first embodiment of the present invention.

[0014] In Figure 1, the CPU 101 comprises at least one processor or circuit. The CPU 101 controls various parts of the imaging device 100 by executing a program stored in its internal memory, and also realizes the functions of the imaging device 100 described below. The imaging drive control unit 1012 controls the imaging sensor 102 based on commands from the control unit 1011 within the CPU 101.

[0015] The imaging sensor 102 is composed of a CMOS image sensor, and a light-receiving element and an amplifier for amplifying an electrical signal are arranged for each pixel. Further, in the present embodiment, the imaging sensor 102 is a stacked CMOS image sensor, and a wiring layer for reading pixel information is arranged on the back surface of the pixel. The stacked CMOS image sensor has a feature that it is less affected by a magnetic field because the wiring length of the circuit part is shorter than that of a non-stacked sensor.

[0016] The imaging sensor 102 photoelectrically converts the light from the subject received by each pixel, and converts the analog signal into digital data by an A / D converter in the imaging sensor 102. The image data based on the digital data obtained from each pixel is stored in the temporary memory 1014 in the CPU 101.

[0017] In the case of the shooting standby state for displaying a through image (live view image), the image data output from the imaging sensor 102 is stored in the temporary memory 1014 according to the thinning drive command for the through image from the control unit 1011. The image data stored in the temporary memory 1014 is subjected to image correction processing by the image correction unit 1015, then converted into display data by the display image conversion unit 1016, and sent to the display unit 103 to be displayed as a live view image.

[0018] When the user presses the release button, image data is output from the imaging sensor 102 that has been driven and controlled for main shooting according to the instruction of the imaging drive control unit 1012. The image data stored on the temporary memory 1014 is corrected by the image correction unit 1015, subjected to compression processing for recording (JPEG encoding processing) by the image compression unit 1013, and sent to the recording unit 104 to be recorded as a still image.

[0019] When the user presses the video recording button, the imaging sensor 102, which is controlled for video recording by the imaging drive control unit 1012, sequentially outputs multiple frames of image data. The image data of each frame stored in the temporary memory 1014 is corrected by the image correction unit 1015, and then compressed for video recording by the image compression unit 1013, and recorded as a video in the recording unit 104. For simplicity, although not shown in Figure 1, the imaging device 100 also includes an operation unit for user input.

[0020] The operating modes of the imaging device 100 typically include a still image mode for capturing still images and a video mode for capturing video.

[0021] More specifically, the still image mode includes a single-shot mode, which captures one still image each time the shutter release button is pressed, and a continuous shooting mode, which captures still images continuously while the shutter release button is held down. The continuous shooting mode also includes a high-speed continuous shooting mode, which captures more images per unit of time, and a low-speed continuous shooting mode, which captures relatively fewer images per unit of time.

[0022] The video mode includes multiple operating modes with different resolutions for the recorded video. For example, the video mode includes an 8K recording mode with 7680 horizontal pixels x 4320 horizontal pixels per screen, a 4K recording mode with 3840 horizontal pixels x 2160 vertical pixels per screen, and an FHD recording mode with 1920 horizontal pixels x 1080 vertical pixels per screen. The frame rate can also be changed in video mode. For example, in video mode, it is possible to set the frame rate to 120 frames per second (fps), 60 fps, or 30 fps. The operating mode of the imaging device 100 may be changed according to user operation, or the control unit 1011 may automatically change to the optimal operating mode for the user.

[0023] The temperature sensor 105 is located inside the imaging device 100 and outputs temperature data from its vicinity. The control unit 1011 can estimate the temperature of any part of the imaging device 100 based on the output data of the temperature sensor 105. Furthermore, there may be more than one temperature sensor 105. Based on the output data of two or more temperature sensors 105, the control unit 1011 can estimate the temperature of the imaging device 100 in more detail. The control unit 1011 can change the control of the imaging device 100 according to the temperature information. For example, if the estimated temperature of the imaging sensor 102 exceeds a predetermined temperature, the control unit 1011 sends a command to the imaging drive control unit 1012 to stop the imaging operation. At the same time, the control unit 1011 sends a command to the power supply control unit 106 to turn off the imaging power supply unit 1072. This makes it possible to safely stop the imaging operation when the temperature of the imaging sensor 102 falls outside the usable range.

[0024] The power control unit 106 controls the power supply unit 107 based on commands from the control unit 1011. For example, the power control unit 106 controls each power supply within the power supply unit 107 by switching them on / off and changing the output voltage. In Figure 1, the power control unit 106 is shown as a separate functional block from the CPU 101, but the power control unit 106 may be configured within the CPU 101. Alternatively, the control unit 1011 may directly control the power supply unit 107.

[0025] The power supply unit 107 is responsible for converting the power supplied from the battery 108 or the USB power supply unit (USB power supply) 110 into the required voltage and current and supplying it to each element of the imaging device 100. The CPU power supply unit 1071 is a power supply circuit that supplies power to the CPU 101. The imaging power supply unit 1072 is a power supply circuit that supplies power to the imaging sensor 102. The imaging power supply unit 1072 may consist of not just one power supply circuit, but multiple power supply circuits. In addition, although only the CPU power supply unit 1071 and the imaging power supply unit 1072 are shown in Figure 1, the power supply unit 107 may also include power supplies that supply power to the display unit 103, the recording unit 104, and other devices.

[0026] Battery 108 is the power source for the imaging device 100 and is, for example, a removable lithium-ion battery. Alternatively, a DC coupler can be inserted in place of the lithium-ion battery in the battery 108 mounting area. A DC coupler is a power adapter that supplies the necessary voltage to the camera from the commercial power source via an AC / DC adapter.

[0027] The battery monitoring unit 109 monitors the voltage and discharge current of the battery 108 and transmits the information to the control unit 1011. The battery monitoring unit 109 can also calculate the internal resistance of the battery 108 from the discharge current and voltage drop. Based on the battery information provided by the battery monitoring unit 109, the control unit 1011 changes the control, for example, by putting the imaging device 100 into a low power consumption state, if the remaining capacity of the battery 108 is low or the internal resistance is increasing.

[0028] The USB power supply unit 110 is equipped with a USB Type-C connector and receives power from a power supply device connected to the connector in accordance with the USB Power Delivery standard. The USB power supply unit 110 outputs the power received from the connected power supply device to the power supply unit 107. The power supply device connected to the USB power supply unit 110 is, for example, a mobile battery or an AC adapter with a USB cable. The imaging device 100 can also operate using power supplied from the USB power supply unit 110 instead of the battery 108.

[0029] Next, Figures 2(a) and 2(b) are exploded view and perspective view, respectively, showing the implementation configuration of the imaging device.

[0030] The main board 201 and the imaging board 202 are located inside the housing of the imaging device 100. The main board 201 is a control board on which the CPU 101 and power supply unit 107 shown in Figure 1 are mounted. The imaging board 202 is on which the imaging sensor 102 and imaging power supply unit 1072 shown in Figure 1 are mounted. In order for the imaging sensor 102 to efficiently capture light, the imaging board 202 is located closer to the lens than the main board 201.

[0031] The chassis 209 is connected to the main board 201 and serves to increase rigidity while also dissipating heat to the housing of the imaging device 100.

[0032] Power is supplied from the power supply unit 107 on the main board 201 to the imaging power supply unit 1072 on the imaging board 202 via the following path. First, the imaging power supply flexible circuit board (hereinafter referred to as FPC: Flexible printed circuits) 203 is connected to the main board 201 via the imaging power supply MAIN connector 204 (204a, 204b). The imaging power supply FPC 203 is connected to the imaging board 202 via the imaging power supply IMG connector 205 (205a, 205b). Then, power is supplied from the power supply unit 107 mounted on the main board 201 to the imaging power supply unit 1072 via the path of connector 204a, 204b → FPC 203 → IMG connector 205a, 205b.

[0033] The transmission of data signals from the imaging sensor 102 on the imaging board 202 to the CPU 101 on the main board 201, and the transmission of control signals from the CPU 101 to the imaging sensor 102, are performed via the following paths. First, the imaging signal FPC 206 is connected to the imaging board 202 via the imaging signal IMG connector 208 (208a, 208b). The imaging signal FPC 206 is connected to the main board 201 via the imaging signal MAIN connector 207 (207a, 207b). Then, the data signals from the imaging sensor 102 are transmitted to the CPU 101 via the main board 201 through the path 208a, 208b → FPC 206 → connector 207a, 207b. Conversely, control signals from the CPU 101 are transmitted to the imaging sensor 102 via the reverse path.

[0034] Furthermore, the imaging device 100 is equipped with an image blur correction mechanism that detects camera shake and moves the imaging board 202 according to the amount of shake detected. In the imaging device 100, the imaging board 202 is a movable part that can be physically moved for image blur correction. On the other hand, the main board 201 and the chassis 209 are non-movable parts. The imaging power supply FPC 203 and the imaging signal FPC 206 that connect the movable and non-movable parts are made of sufficiently flexible material. The imaging power supply FPC 203 connects the main board 201, which is a non-movable part, and the imaging board 202, which is a movable part, via the imaging power supply MAIN connector 204 (204a, 204b) and the imaging power supply IMG connector 205 (205a, 205b). Furthermore, the imaging signal FPC206 connects the non-movable main board 201 and the movable imaging board 202 via the imaging signal MAIN connector 207 (207a, 207b) and the imaging signal IMG connector 208 (208a, 208b).

[0035] Figure 3 shows an example of the imaging power supply unit 1072 and its surrounding circuit configuration as shown in Figure 2. The control unit 1011, imaging sensor 102, power control unit 106, battery 108, and USB power supply unit 110 are the same as in Figure 1.

[0036] If the battery 108 has two cells, the voltage from the battery 108 is approximately 5V to 8.4V. Also, the voltage output from the USB power supply unit 110 varies depending on the power supply capacity of the power supply device connected to the USB power supply unit 110. For example, if the power supply device can output voltages such as 5V, 9V, and 15V, one of these voltages will be input to the USB power supply unit 110. The USB power supply unit 110 will output the input voltage as is, or convert it to an equivalent battery voltage.

[0037] As shown in Figures 2(a) and (b), the imaging power supply unit 1072 is mounted on the imaging board 202. The imaging power supply unit 1072 is a power supply circuit that converts the voltage supplied from the battery 108 or the USB power supply unit 110 via the main board 201 into the voltage required by the analog power supply and digital power supply of the imaging sensor 102 and outputs it. The voltages required by the analog power supply and digital power supply of the imaging sensor 102 are lower than the voltage from the battery 108. Also, the voltages required by the analog power supply and digital power supply of the imaging sensor 102 are lower than the voltage from the USB power supply unit 110. Therefore, the imaging power supply unit 1072 is a step-down circuit that converts the input voltage supplied from the battery 108 or the USB power supply unit 110 via the main board 201 into an output voltage lower than the input voltage.

[0038] The first DC-DC converter 301 is a power supply circuit (step-down circuit) that generates the voltage to be input to the first linear regulator 302 and the second linear regulator 303 for the analog power supply of the imaging sensor 102. The first DC-DC converter control unit 3011 is a control circuit that controls the switch element 3012a and the switch element 3012b so that the output voltage of the first DC-DC converter 301 becomes a desired value.

[0039] Switch elements 3012a and 3012b are, for example, FETs and are switch elements that constitute the first DC-DC converter 301. Step-down inductors 1Phasea (3013a) and 1Phaseb (3013b) are inductors that constitute the first DC-DC converter 301.

[0040] The first linear regulator 302 and the second linear regulator 303 are linear regulators that step down the output voltage of the first DC-DC converter 301 to the voltage required by the analog power supply of the imaging sensor 102.

[0041] The second DC-DC converter 311 is a power supply circuit that generates a voltage for the digital power supply of the imaging sensor 102. The second DC-DC converter control unit 3111 is a control circuit that controls switch elements 3112a and 3112b so that the output voltage of the second DC-DC converter 311 becomes a desired value.

[0042] Switch elements 3112a and 3112b are, for example, FETs and are switch elements that constitute the second DC-DC converter 311. Step-down inductors 2Phasea (3113a) and 2Phaseb (3113b) are inductors that constitute the second DC-DC converter 311.

[0043] The first DC-DC converter 301 and the second DC-DC converter 311 are preferably DC-DC converters capable of high-speed switching operation of 3 MHz or higher. High-speed switching operation can reduce noise in the image obtained by the imaging sensor 102 caused by the magnetic fields radiated from the buck inductors 1Phasea (3013a), 1Phaseb (3013b), 2Phasea (3113a), and 2Phaseb (3113b).

[0044] As described above, by arranging the imaging power supply unit 1072 on the imaging board 202, the voltage from the battery 108 or the USB power supply unit 110 is sent from the imaging board 201 to the imaging power supply unit 1072 on the imaging board 202 via the imaging power supply FPC 203 without stepping down the voltage. Therefore, the current flowing through the imaging power supply FPC 203 can be reduced.

[0045] For example, suppose the peak power consumption of the imaging sensor 102 is about 22W. In this case, if the imaging power supply unit 1072 is located on the main board 201, the current flowing through the imaging power supply FPC 203 will be about 10A. On the other hand, if the imaging power supply unit 1072 is located on the imaging board 202, the current flowing through the imaging power supply FPC 203 can be reduced to about 2A. As a result, the imaging sensor 102 becomes less susceptible to the effects of magnetic radiation from the current flowing through the imaging power supply FPC 203.

[0046] Furthermore, reducing the current flow allows for thinner wiring in the imaging power supply FPC203. This increases the flexibility of the FPC, which in turn improves the range of motion of the image stabilization mechanism.

[0047] From a power consumption perspective, unnecessary power loss due to the impedance of the imaging power supply FPC203 can also be reduced. Furthermore, since the first DC-DC converter 301 can be placed near the first linear regulator 302 and the second linear regulator 303, it is possible to set it to a low voltage. Therefore, the losses of the first linear regulator 302 and the second linear regulator 303 can also be reduced.

[0048] As the image sensor 102 becomes higher pixel count and faster readout (including full pixel readout), it will be able to cope even if power consumption increases.

[0049] Figure 4 shows another example of the imaging power supply unit 1072 and surrounding circuit configuration shown in Figure 2.

[0050] The control unit 1011, imaging sensor 102, power control unit 106, battery 108, and USB power supply unit 110 are the same as in Figure 1.

[0051] The imaging power supply unit 1073 is a power supply circuit located on the main board 201 in Figure 2, and includes a DC-DC converter 401 that generates a voltage to be input to the switched capacitor 411. The DC-DC converter control unit 4011 is a control circuit that controls the switching element 4012 so that the output voltage of the DC-DC converter 401 becomes a desired value. The switching element 4012 is, for example, an FET, and is a switching element that constitutes the DC-DC converter 401. The step-up / step-down inductor 4013 is an inductor that constitutes the DC-DC converter 401.

[0052] The imaging power supply unit 1072 is located on the imaging board 202 in Figure 2 and is a power supply circuit that generates the voltage for the analog power supply of the imaging sensor 102.

[0053] The switched capacitor 411 is a power supply circuit (step-down circuit) composed of multiple capacitors and switches. The switched capacitor 411 converts the voltage output from the DC-DC converter 401 into an output voltage of 1 / N (where N is a natural number), generating the voltage for the analog power supply of the imaging sensor 102.

[0054] The third linear regulator 412 and the fourth linear regulator 413 are linear regulators that step down the voltage output from the switched capacitor 411 to the voltage required by the analog power supply of the imaging sensor 102.

[0055] As described above, in the configuration shown in Figure 4, the imaging board 201 outputs the voltage from the battery 108 or the USB power supply unit 110, converted by the imaging power supply unit 1073 on the main board 201 into an input voltage for the switched capacitor 411. Then, similar to Figure 3, the imaging power supply unit 1072 is placed on the imaging board 202, and the imaging power supply unit 1072 converts the input voltage from the imaging power supply unit 1073 into a lower voltage. As a result, the current flowing through the imaging power supply FPC 203 can be reduced. Furthermore, since the imaging power supply unit 1072 in Figure 4 does not require an inductor, the imaging sensor 102 is not affected by magnetic radiation from the inductor.

[0056] Furthermore, the presence of the imaging power supply unit 1073 ensures that power can be stably supplied to the imaging sensor 102 even if the voltage of the battery 108 drops. Since the imaging power supply unit 1073 is located on the main board 201, the imaging sensor 102 is less susceptible to magnetic radiation from the step-up / step-down inductor 4013.

[0057] On the other hand, in the imaging power supply unit 1072, the voltage is boosted in the DCDC converter 401 and stepped down in the switched capacitor 411, resulting in lower power efficiency for the entire imaging device 100. However, the imaging power supply unit 1072 can also operate in an efficiency-prioritizing mode by stepping down the voltage in the DCDC converter 401 and setting the switched capacitor 411 to 1 / 1 (through).

[0058] Next, Figure 5 is a flowchart showing the control of the imaging power supply unit 1072 and the imaging power supply unit 1073 shown in Figure 4, performed by the control unit 1011 and the power supply control unit 106.

[0059] In step S501, for example, when the user performs an operation such as turning on the power switch (not shown) of the imaging device 100, the control unit 1011 performs the startup process for the imaging device 100.

[0060] In step S502, the power control unit 106 configures the power supply unit 107. For DC-DC converters, these configurations include voltage settings, variable drive switch frequency settings, fixed PWM control settings, or PFM (pulse frequency modulation) selection. For switched capacitors, there is a setting to switch the magnification to 1 / N (where N is a natural number), such as 1 / 2 or 1 / 3.

[0061] In step S503, the control unit 1011 determines the operating mode of the imaging device 100. If the imaging device 100 is in still image mode, proceed to S504. If the imaging device 100 is in video mode, proceed to S506.

[0062] Here, "video mode" refers to an example of a mode in which the readout speed of image data during shooting is slow and the peak current consumption is relatively small, while "still image mode" refers to an example of a mode in which the readout speed of image data during shooting is fast and the peak current consumption is relatively large. In the case of a video mode in which the readout speed of image data is fast and the peak current consumption is relatively large, the process may proceed to S504 instead of S506. Conversely, in the case of a still image mode in which the readout speed of image data during shooting is slow and the peak current consumption is relatively small, the process may proceed to S506 instead of S504.

[0063] In step S504, the power control unit 106 sets the output voltage of the DC-DC converter 401. Here, for example, the output voltage of the DC-DC converter 401 is set to 12V.

[0064] In step S505, the power control unit 106 sets the multiplier for the switched capacitor 411. Here, the multiplier for the switched capacitor 411 is set to 1 / 3. When a 12V voltage is input from the DC-DC converter 401, the switched capacitor 411 converts this 12V input voltage to an output voltage of 4V, which is 1 / 3 of the original voltage.

[0065] On the other hand, in step S506, which proceeds when video mode is enabled, the power control unit 106 sets the output voltage of the DC-DC converter 401. Here, for example, the output voltage of the DC-DC converter 401 is set to 4V.

[0066] In step S507, the power control unit 106 sets the multiplier for the switched capacitor 411. Here, the multiplier for the switched capacitor 411 is set to 1 / 1. Therefore, when a voltage of 4V is input from the DC-DC converter 401, 4V is output as the output voltage.

[0067] Once the DCDC converter 401 and switched capacitor 411 are configured, the power supply control unit 106 starts the power supply process by the imaging power supply unit 1073 and the imaging power supply unit 1072, and power is supplied to the imaging sensor 102. In step S508, the control unit 1011 starts driving the imaging sensor 102 via the imaging drive control unit 1012. The control unit 1011 also displays the image captured by the imaging sensor 102 as a live view image on the display unit 103 via the temporary memory 1014, the image correction unit 1015, and the display image conversion unit 1016.

[0068] In step S509, the control unit 1011 determines whether the operating mode of the imaging device 100 needs to be switched. If an operating mode switch occurs, the process returns to S503. If there is no operating mode switch, the process proceeds to S510.

[0069] In step S510, the control unit 1011 determines the state of the power switch (not shown) of the imaging device 100. If the power switch of the imaging device 100 is OFF, the process proceeds to S511. If the power switch of the imaging device 100 remains ON, the process returns to S509.

[0070] In step S511, the power control unit 106 stops the output of the imaging drive control unit 1012 and the power supply unit 107, thereby stopping the operation of the imaging device 100.

[0071] As shown in Figure 5, when the imaging device 100 is in a mode with a relatively large peak current, such as still image mode, the output voltage of the DC-DC converter 401 is increased in S504 and S505. This reduces the peak current flowing through the imaging power supply FPC 203 when power is supplied to the switched capacitor 411 via the imaging power supply FPC 203.

[0072] Furthermore, when the imaging device 100 is in a mode with a relatively small peak current, such as video mode, only the step-down operation of the DC-DC converter 401 is performed in S506 and S507. By passing the voltage through the switched capacitor 411 without switching operation, power loss in the imaging power supply unit 1072 can be reduced, and the temperature rise of the imaging sensor 102 can be suppressed.

[0073] Furthermore, in the flowchart of Figure 5, the operating mode of the imaging device 100 is determined in step S503, but the temperature of the imaging sensor 102 may be determined based on the temperature data acquired by the temperature sensor 105. If the temperature of the imaging sensor 102 is above a predetermined value, the process proceeds to S506; if it is below the predetermined value, the process proceeds to S504. In other words, if the temperature of the imaging sensor 102 rises, only the step-down operation of the DC-DC converter 401 is performed, the multiplier of the switched capacitor 411 is set to 1 / 1, and the input voltage is output as is. This reduces the power loss of the imaging power supply unit 1072 and suppresses the temperature rise of the imaging sensor 102.

[0074] Figure 6 shows another example of the imaging power supply unit 1072 and surrounding circuit configuration shown in Figure 1.

[0075] The control unit 1011, imaging sensor 102, power control unit 106, battery 108, and USB power supply unit 110 are the same as in Figure 1.

[0076] The imaging power supply unit 1073 is a power supply circuit located on the main board 201 in Figure 2, and includes a DC-DC converter 601 that generates the voltage to be input to the switched capacitor 611. The voltage monitoring unit 6014 monitors the output voltage of the switched capacitor 611 and feeds it back to the DC-DC converter control unit 6011.

[0077] Based on feedback from the voltage monitoring unit 6014, the DC-DC converter control unit 6011 controls the DC-DC converter switching element 6012 so that the output voltage of the switched capacitor 611 reaches a desired value. This adjusts the output voltage of the DC-DC converter 601.

[0078] The switching element 6012 is, for example, a FET and is a switching element that constitutes the DC-DC converter 601. The step-up / step-down inductor 6013 is an inductor that constitutes the DC-DC converter 601.

[0079] The imaging power supply unit 1072 is located on the imaging board 202 in Figure 2 and is a power supply circuit that generates the voltage for the analog power supply of the imaging sensor 102.

[0080] The switched capacitor 611 is a power supply circuit (step-down circuit) composed of multiple capacitors and switches. The switched capacitor 611 converts the voltage output from the DC-DC converter 601 into an output voltage of 1 / N (where N is a natural number) to generate the voltage for the analog power supply of the imaging sensor 102.

[0081] In the circuit configuration shown in Figure 6, the voltage monitoring unit 6014 monitors the output voltage of the switched capacitor 611. Based on feedback from the voltage monitoring unit 6014, the DC-DC converter control unit 6011 controls the switching element 6012 so that the output voltage of the switched capacitor 611 reaches a desired value. This adjusts the output voltage of the DC-DC converter 601.

[0082] For example, if the input voltage to the switched capacitor 611 drops due to the wiring resistance from the DC-DC converter 601 to the switched capacitor 611, the DC-DC converter control unit 6011 controls the DC-DC converter 601 to increase its output voltage. The output voltage of the DC-DC converter 601 will also change according to the multiplier (1 / N) of the switched capacitor 611. For example, if the multiplier of the switched capacitor 611 is set to 1 / 3 and the output voltage of the DC-DC converter 1073 is set to 12V, the output voltage of the switched capacitor 611 will be 4V, which is 1 / 3 of 12V. In this state, the voltage monitoring unit 6014 monitors the output voltage of the switched capacitor 611. If the output voltage of the switched capacitor 611 falls below 4V, the voltage monitoring unit 6014 notifies the DC-DC converter 6011 that the output voltage of the switched capacitor 611 has dropped. Based on a notification from the voltage monitoring unit 604, the DC-DC converter control unit 601 controls the DC-DC converter 601 to increase its output voltage.

[0083] This prevents the output voltage of the switched capacitor 611 from decreasing. Furthermore, it prevents the output voltage from the switched capacitor 611 from falling below the lower limit of the voltage range required by the imaging sensor 102.

[0084] The control details of the imaging power supply unit 1072 and the imaging power supply unit 1073 in Figure 6 are the same as those in the flowchart in Figure 5.

[0085] Figure 7 shows another example of the imaging power supply unit 1072 and surrounding circuit configuration shown in Figure 1.

[0086] The control unit 1011, imaging sensor 102, power control unit 106, battery 108, and USB power supply unit 110 are the same as in Figure 1.

[0087] The imaging power supply unit 1072, located on the imaging board 202, is a power supply circuit that converts the voltage supplied from the battery 108 or the USB power supply unit 110 via the main board 201 into the voltage required by the digital power supply of the imaging sensor 102 and outputs it.

[0088] The DC-DC converter 702 is a power supply circuit that steps down the voltage output from the switched capacitor 701 (step-down circuit) to generate the voltage for the digital power supply of the imaging sensor 102.

[0089] The DC-DC converter control unit 7021 is a control circuit that controls the switch element 7022a and the switch element 7022b so that the output voltage of the DC-DC converter 702 becomes a desired value.

[0090] Switch elements 7022a and 7022b are, for example, FETs and are switch elements that constitute the DC-DC converter 702. Step-down inductors Phasea (7023a) and Phaseb (7023b) are inductors that constitute the DC-DC converter 702.

[0091] The switched capacitor 701 is a power supply circuit composed of multiple capacitors and switches. The switched capacitor 701 converts the input voltage output from the battery 108 or the USB power supply unit 110 into an output voltage of 1 / N, generating the voltage for the input power supply of the DC-DC converter 702.

[0092] Depending on the model, the minimum ON time of the switch elements 7022a and 7022b differs for the DC-DC converter 702.

[0093] Furthermore, the minimum required ON time can be determined as follows, depending on the variable SW frequency (switch frequency).

[0094] Tswon[μs]=1 / Fsw[MHz]×Vout[V] / Vin[V] (Tswon: Minimum ON time, Fsw: Switch frequency, Vout: Output voltage, Vin: Input voltage) Based on the above equation, in order to operate the DC-DC converter 702 at a stable SW frequency, it is necessary to properly set the input voltage of the DC-DC converter 702.

[0095] For example, let's assume the minimum ON time for switch elements 7022a and 7022b is 40 ns. Also, let's assume that the input voltage for the imaging sensor 102 is 1.25 V.

[0096] If you want the DCDC converter 702 to operate stably at 5.0MHz, it can only accept an input voltage of up to 6.25V.

[0097] When battery 108 has two cells, the voltage of battery 108 is approximately 5V to 8.4V. Therefore, when the voltage of battery 108 is converted to half by the switched capacitor 701, the output voltage of the switched capacitor 701 becomes 2.5V to 4.2V. As a result, the DC-DC converter 702 can operate stably at 5.0MHz.

[0098] Furthermore, if the battery 108 has 3 cells, the voltage of the battery 108 is approximately 9V to 12.6V. Therefore, when the voltage of the battery 108 is converted to 1 / 3 by the switched capacitor 701, the output voltage of the switched capacitor 701 becomes 3.0V to 4.2V. As a result, the DC-DC converter 702 can be operated stably at 5.0MHz.

[0099] When the input voltage to the switched capacitor 701 is high, including during DC coupler operation or USB power supply, the voltage of the battery 108 is converted to 1 / 3 of that voltage by the switched capacitor 701, allowing for stable operation at 5.0MHz.

[0100] Next, Figure 8 is a flowchart showing the control contents of the imaging power supply unit 1072 performed by the control unit 1011 and the power supply control unit 106.

[0101] In step S801, for example, when the user performs an operation such as turning on the power switch (not shown) of the imaging device 100, the control unit 1011 performs the startup process for the imaging device 100.

[0102] In step S802, the power control unit 106 configures the power supply unit 107. For DC-DC converters, these configurations include voltage settings, drive switch frequency settings, PWM fixed control settings, or PFM (pulse frequency modulation) selection. For switched capacitors, there is a setting to switch the magnification to 1 / N (where N is a natural number), such as 1 / 2 or 1 / 3.

[0103] In step S803, the current operating mode of the imaging device 100 is checked.

[0104] In step S804, the control unit 1011 determines whether a switching frequency of 5 MHz or higher is required for the DC-DC converter 702.

[0105] It is known that when a CMOS image sensor is exposed to magnetic noise, an induced electromotive force is generated in its internal circuitry, causing fluctuations in the output of the pixel signal and potentially degrading image quality. The frequency of magnetic noise that is most likely to cause image quality degradation varies depending on the pixel data readout period, etc. Furthermore, image quality degradation tends to be less likely as the frequency of magnetic noise increases. In addition, image quality degradation tends to be more pronounced in shooting modes with higher ISO sensitivity.

[0106] Based on the above, in order to prevent image quality degradation, it is necessary to set the frequency of magnetic noise radiated from the DCDC converter 702 so that it does not match the drive frequency that is prone to image quality degradation, depending on the operating mode of the imaging device 100.

[0107] In step S804, for example, if the imaging device 100 is in a shooting mode with an ISO sensitivity of 12800 or higher, it is determined that the drive frequency of the DCDC converter 702 needs to be set to 5MHz or higher, and the process proceeds to S805. If the shooting mode is not in an ISO sensitivity of 12800 or higher, no image quality degradation occurs even if the switching frequency of the DCDC converter 702 is 5MHz or lower. Therefore, if the shooting mode is not in an ISO sensitivity of 12800 or higher, the process proceeds to S811.

[0108] In step S805, the control unit 1011 determines whether a DC coupler is inserted into the battery 108 mounting section. If a DC coupler is inserted, the process proceeds to S807. If a DC coupler is not inserted and a lithium-ion battery is inserted, the process proceeds to S806.

[0109] In step S806, the control unit 1011 determines whether an external power supply is connected to the USB power supply unit 110. If an external power supply is connected to the USB power supply unit 110, it determines whether the voltage supplied from the external power supply is 15V or higher. If a voltage of 15V or higher is supplied from the external power supply, the process proceeds to S807. If the voltage supplied from the external power supply is not 15V or higher (for example, 5V, 9V), or if an external power supply is not connected to the USB power supply unit 110 and the imaging device 100 is operating solely on power supplied from the lithium-ion battery inserted in the battery 108, the process proceeds to S809.

[0110] In step S807, the power supply control unit 106 sets the multiplier of the switched capacitor 701 to 1 / 3.

[0111] In step S808, the power control unit 106 sets the DC-DC converter 702 to a PWM control mode with a fixed switching frequency of 5MHz.

[0112] In step S809, the power supply control unit 106 sets the multiplier of the switched capacitor 701 to 1 / 2.

[0113] In step S810, the power control unit 106 sets the DC-DC converter 702 to a PWM control mode with a fixed switching frequency of 5MHz.

[0114] In step S811, the power supply control unit 106 sets the multiplier of the switched capacitor 701 to 1 / 3.

[0115] In step S812, the control unit 1011 determines whether a switching frequency of 3 MHz or higher is required for the DC-DC converter 702.

[0116] For example, if the imaging device 100 is in a shooting mode with an ISO sensitivity of 6400 or higher and less than 12800, it is determined that the switching frequency of the DCDC converter 702 must be 3MHz or higher, and the process proceeds to S813. If the ISO sensitivity is not 6400 or higher, the image quality will not deteriorate even if the switching frequency of the DCDC converter 702 is 3MHz or lower. If the ISO sensitivity is not 6400 or higher, the process proceeds to S814. Alternatively, if the imaging device 100 is in an operating mode that does not record captured images (for example, live view display mode), it is acceptable for the image quality to deteriorate. Therefore, the process may proceed to S814 in the case of an operating mode that does not record captured images.

[0117] In step S813, the power control unit 106 sets the DC-DC converter 702 to a PWM control mode with a fixed switching frequency of 3MHz.

[0118] In step S814, the power supply control unit 106 changes the switching of the DC-DC converter 702 to PFM (pulse frequency modulation) operation. In PFM operation mode, the switching frequency of the DC-DC converter 702 changes according to the current consumption. Basically, when the current consumption is small, the switching frequency decreases, and the power supply efficiency improves. For example, the DC-DC converter 702 is assumed to operate at 1MHz when the current consumption is 500mA and at 3MHz when the current consumption is 1A.

[0119] In step S815, the control unit 1011 determines whether or not the operating mode of the imaging device 100 has been switched. If the operating mode has been switched, the process returns to S804. If the operating mode has not been switched, the process proceeds to S816.

[0120] In step S816, the control unit 1011 determines the state of the power switch (not shown) of the imaging device 100. If the power switch of the imaging device 100 is OFF, the process proceeds to S817. If the power switch of the imaging device 100 remains ON, the process returns to S815.

[0121] In step S817, the power control unit 106 stops the output of the imaging drive control unit 1012 and the power supply unit 107, thereby stopping the operation of the imaging device 100.

[0122] According to the flowchart in Figure 8, when the imaging device 100 is in a shooting mode with an ISO sensitivity of 12800 or higher, the output voltage of the switched capacitor 701 is adjusted so that the switching frequency of the DC-DC converter 702 can be maintained at 5 MHz, even if the voltage of the power supply source of the imaging device 100 changes.

[0123] For example, in S807, a 15V voltage is input to the switched capacitor 701 from the USB power supply unit 110 or the DC coupler. The switched capacitor 701 converts this 15V input voltage to an output voltage of 5V (1 / 3 of the original voltage) and outputs it. The 5V output voltage from the switched capacitor 701 is input to the DC-DC converter 702. If the image sensor 102 requires a voltage of 1.25V, the minimum ON time of the DC-DC converter 702 must be 50ns or less in order to operate at 5MHz. The minimum ON time of the DC-DC converter 702 is, for example, 40ns, and it can operate at a switching frequency of 5MHz.

[0124] Furthermore, in S809, for example, a 4.5V voltage from the battery 108 is input to the switched capacitor 701. The switched capacitor 701 converts this 4.5V input voltage to an output voltage of 2.25V (half of the original voltage) and outputs it. The 2.25V output voltage from the switched capacitor 701 is input to the DC-DC converter 702. If the image sensor 102 requires a voltage of 1.25V, the minimum OFF time of the DC-DC converter 702 must be 89ns or less in order to operate at 5MHz. The minimum OFF time of the DC-DC converter 702 is, for example, 40ns, and it can operate at a switching frequency of 5MHz.

[0125] As a result, the frequency of magnetic noise radiated from the DCDC converter 702 can be avoided from matching the frequency at which the image quality of the image sensor 102 is prone to degradation, thereby reducing image quality degradation.

[0126] Furthermore, when the imaging device 100 is in a shooting mode with an ISO sensitivity of 6400 or higher and less than 12800, the output voltage of the switched capacitor 701 is adjusted so that the switching frequency of the DCDC converter 702 is maintained at 3MHz. This prevents the frequency of magnetic noise radiated from the DCDC converter 702 from matching a frequency that is prone to image quality degradation of the image sensor 102, thereby reducing image quality degradation. In addition, compared to operating the DCDC converter 702 at 5MHz, power loss can be reduced, and image quality degradation due to temperature rise of the image sensor 102 can be reduced.

[0127] Furthermore, when the imaging device 100 is in a shooting mode with an ISO sensitivity of less than 6400, or in an operating mode that does not record captured images (for example, live view display mode), the switching frequency of the DCDC converter 702 drops to less than 3 MHz. This reduces power loss and mitigates image quality degradation due to temperature rise of the image sensor 102.

[0128] Note that the types of operating modes of the imaging device 100 and the switching frequencies of the DCDC converter 702 in each operating mode described in Figure 8 are just examples. For other operating modes of the imaging device 100, the DCDC converter 702 may be controlled to have different switching frequencies in order to reduce image quality degradation.

[0129] Figure 9 shows the layout of the components of the imaging power supply unit 1072 shown in Figure 3, which are arranged on the imaging substrate 202 shown in Figure 2.

[0130] Connectors 205b and 208b are the same as in Figure 2. The first DC-DC converter control unit 3011, switch element 3012a, switch element 3012b, step-down inductor 1Phasea (3013a), step-down inductor 1Phaseb (3013b), first linear regulator 302, second linear regulator 303, second DC-DC converter control unit 3111, switch element 3112a, switch element 3112b, step-down inductor 2Phasea (3113a), and step-down inductor 2Phaseb (3113b) are the same as in Figure 3.

[0131] The dividing line 905 is a dividing line that bisects the area of ​​the imaging substrate 202. The imaging substrate 202 is divided by the dividing line 905 into a region 202a and a region 202b of equal area.

[0132] Region 202a contains the first DC-DC converter control unit 3011, a switch element 3012a, a step-down inductor 1Phasea (3013a), a linear regulator 1 (302), the second DC-DC converter control unit 3111, a switch element 3112a, and a step-down inductor 2Phasea (3113a).

[0133] Region 202b contains a switch element 3012b, a step-down inductor 1Phaseb(3013b), a first linear regulator 303, a switch element 3112b, and a step-down inductor 2Phaseb(3113b).

[0134] As shown in Figure 9, when each component (a circuit element with the same function, provided in multiples) is laid out, the number of inductors placed in region 202a is equal to the number of inductors placed in region 202b. Also, the number of switch elements placed in region 202a is equal to the number of switch elements placed in region 202b. Furthermore, the number of linear regulators placed in region 202a is equal to the number of linear regulators placed in region 202b. This prevents heat generated by losses in the inductors, switch elements, and linear regulators from concentrating in certain areas of the imaging substrate 202, thereby reducing the temperature rise of the imaging sensor 102.

[0135] In addition, although the dividing line 905 was a dividing line that bisects the area of ​​the imaging substrate 202, the substrate may also be divided by dividing lines that divide the substrate into N equal parts (where N is an integer of 2 or more), so that the number of inductors, switch elements, and linear regulators placed in each divided region is equal. By doing so, the heat-generating parts can be dispersed and image quality degradation can be prevented.

[0136] The step-down inductors 1Phasea(3013a) and 1Phaseb(3013b) are arranged such that when a positive current flows in the direction of the imaging sensor 102 (not shown), the direction of the magnetic field generated by step-down inductor 1Phasea(3013a) and the direction of the magnetic field generated by step-down inductor 1Phaseb(3013b) are the same.

[0137] Magnetic fields 901 and 903 are arrows indicating the direction of the magnetic field generated from the step-down inductor 1Phasea(3013a) when a positive current flows from the step-down inductor 1Phasea(3013a) towards the imaging sensor 102 (not shown).

[0138] Magnetic fields 902 and 904 are arrows indicating the direction of the magnetic field generated from the step-down inductor 1Phaseb(3013b) when a positive current flows from the step-down inductor 1Phaseb(3013b) towards the imaging sensor 102 (not shown).

[0139] When a positive current flows from the step-down inductor 1Phasea(3013a) and the step-down inductor 1Phaseb(3013b) in the direction of the image sensor 102 (not shown), the magnetic fields 901 and 904 within the winding of the step-down inductor 1Phasea(3013a) are in opposite directions and cancel each other out. Similarly, within the winding of the step-down inductor 1Phaseb(3013b), the magnetic fields 903 and 902 are in opposite directions and cancel each other out.

[0140] As shown in Figure 9, when an even number of step-down inductors 1Phasea (3013a) and step-down inductors 1Phaseb (3013b) are arranged in this configuration, the magnetic fields they generate cancel each other out. Therefore, the degradation of image quality due to magnetic noise in the image captured by the imaging sensor 102 can be reduced.

[0141] In Figure 9, magnetic fields 901 and 904, and magnetic fields 903 and 902 are perpendicular to the image sensor 102 and cancel each other out. However, the step-down inductors 1Phasea (3013a) and 1Phaseb (3013b) may be arranged so that they are parallel to the image sensor 102 and cancel each other out.

[0142] The orientation of the step-down inductors 2Phasea (3113a) and 2Phaseb (3113b) is the same as that of step-down inductors 1Phasea (3013a) and 1Phaseb (3013b). By doing so, the magnetic fields entering the image sensor 102 cancel each other out, preventing image quality degradation.

[0143] (Second embodiment) The following describes an imaging device 200 according to a second embodiment of the present invention. Figures 10(a) and 10(b) are exploded view and perspective view, respectively, showing the mounting configuration of the imaging device 200. In Figure 10, parts that perform the same functions as in Figure 2 are denoted by the same reference numerals as in Figure 2.

[0144] In Figure 10, the main board 201, the imaging board 202, and the imaging power supply board 211 are arranged inside the housing of the imaging device 200.

[0145] The main board 201 is equipped with the CPU 101 and power supply unit 107 shown in Figure 1. The imaging board 202 is equipped with the imaging sensor 102 shown in Figure 1, and in order for the imaging sensor 102 to efficiently capture light, the imaging board 202 is positioned closer to the lens than the main board 201. The imaging power supply board 211 is equipped with the imaging power supply unit 1072 shown in Figure 1.

[0146] Chassis 209 is connected to the main board 201 and serves to increase rigidity while also allowing heat to dissipate from the enclosure.

[0147] Power is supplied from the power supply unit 107 on the main board 201 to the imaging power supply unit 1072 on the imaging power supply board 211 via the following path. First, the imaging power supply FPC 203 is connected to the main board 201 via the imaging power supply MAIN connector 204 (204a, 204b). The imaging power supply FPC 203 is connected to the imaging power supply board 211 via the imaging power supply IMG connector 205 (205a, 205b). Power is then supplied from the power supply unit 107 mounted on the main board 201 to the imaging power supply unit 1072 via the path 204a, 204b → FPC 203 → IMG connector 205a, 205b. The imaging power supply board 211 is fixedly connected to the imaging board 202 via the imaging power supply board connector 212 (212a, 212b), and power is supplied from the imaging power supply unit 1072 to the imaging sensor 102. Alternatively, the imaging power supply board 211 can be considered as part of the imaging board 202, and it can be said that the imaging power supply board 211 is fixed to the main body of the imaging board 202.

[0148] The transmission of data signals from the imaging sensor 102 on the imaging board 202 to the CPU 101 on the main board 201, and the transmission of control signals from the CPU 101 to the imaging sensor 102, are performed via the following paths. First, the imaging signal FPC 206 is connected to the imaging board 202 via the imaging signal IMG connector 208 (208a, 208b). The imaging signal FPC 206 is connected to the main board 201 via the imaging signal MAIN connector 207 (207a, 207b). Then, the data signals from the imaging sensor 102 are transmitted to the CPU 101 via the main board 201 through the path 208a, 208b → FPC 206 → connector 207a, 207b. Conversely, control signals from the CPU 101 are transmitted to the imaging sensor 102 via the reverse path.

[0149] The heat dissipation member 213 is, for example, a rubber-like material with high thermal conductivity. The heat dissipation member 213 connects the imaging substrate 202 and the imaging power supply board 211, and has the effect of dispersing the heat from the imaging sensor 102 on the imaging substrate 202 from the imaging substrate 202 to the imaging power supply board 211.

[0150] The heat dissipation sheet 214 is, for example, a flexible sheet-like material with high thermal conductivity. The heat dissipation sheet 214 is placed on one side of the imaging power supply board 211 facing the main board 201 and is connected to the chassis 209, effectively dissipating heat from the imaging power supply board 211 to the chassis 209. Furthermore, no electrical components are mounted on the side of the imaging power supply board 211 closer to the main board 201, and the imaging power supply unit 1072 is mounted only on the side closer to the imaging board 202. This increases the contact area between the heat dissipation sheet 214 and the imaging power supply board 211, thereby improving heat dissipation.

[0151] The magnetic shielding sheet 215 is, for example, a sheet-shaped magnetic material that shields against magnetic fields. The magnetic shielding sheet 215 is mounted between the imaging substrate 202 and the imaging power supply substrate 211 and has the effect of reducing electromagnetic field noise radiated from the imaging power supply unit 1072 to the imaging sensor 102.

[0152] Furthermore, the imaging device 200 is equipped with an image stabilization mechanism that detects camera shake and moves the imaging board 202 according to the amount of shake detected. The imaging power supply board 211, which is connected to the imaging board 202 via the imaging power supply board connector 212, is a movable part that can physically move for image shake correction. On the other hand, the main board 201 and the chassis 209 are non-movable parts.

[0153] The imaging power FPC 203, imaging signal FPC 206, and heat dissipation sheet 214, which connect the movable and non-movable parts, are made of sufficiently soft material. The imaging power FPC 203 connects the non-movable main board 201 and the movable imaging power board 211 via the imaging power MAIN connector 204 (204a, 204b) and the imaging power IMG connector 205 (205a, 205b). The imaging signal FPC 206 connects the non-movable main board 201 and the movable imaging board 202 via the imaging signal MAIN connector 207 (207a, 207b) and the imaging signal IMG connector 208 (208a, 208b).

[0154] As shown in Figure 10, by mounting the imaging power supply unit 1072 on the imaging power supply board 211 instead of the imaging board 202, it is possible to prevent heat from being transferred to the imaging sensor 102 when the imaging power supply unit 1072 generates heat due to power loss. This prevents degradation of image quality.

[0155] The configuration of the imaging power supply unit 1072 and peripheral circuits mounted on the imaging power supply board 211 is the same as in Figures 3, 4, 6, and 7 of the first embodiment. The control method for the imaging power supply unit 1072 and peripheral circuits is the same as in Figures 5 and 8 of the first embodiment.

[0156] Figure 11 shows the layout of the components of the imaging power supply unit 1072 shown in Figure 3, which are arranged on the imaging power supply board 211 shown in Figure 10.

[0157] Connector 212a is connected to connector 212b on the imaging substrate 202 in Figure 10. The first DC-DC converter control unit 3011, switch element 3012a, switch element 3012b, step-down inductor 1Phasea(3013a), step-down inductor 1Phaseb(3013b), first linear regulator 302, second linear regulator 303, second DC-DC converter control unit 3111, switch element 3112a, switch element 3112b, step-down inductor 2Phasea(3113a), and step-down inductor 2Phaseb(3113b) are the same as in Figure 3.

[0158] The dividing line 1105 is a dividing line that bisects the area of ​​the imaging power supply board 211. The imaging power supply board 211 is divided by the dividing line 1105 into a region 211a and a region 211b of equal area.

[0159] Region 211a contains the first DC-DC converter control unit 3011, switch element 3012a, switch element 3012b, step-down inductor 1Phasea (3013a), step-down inductor 1Phaseb (3013b), and the first linear regulator 302.

[0160] Region 211b is configured to include a second DC-DC converter control unit 3111, a switch element 3112a, a switch element 3112b, a step-down inductor 2Phasea (3113a), a step-down inductor 2Phaseb (3113b), and a second linear regulator 303.

[0161] As shown in Figure 11, when the components are laid out, the number of inductors in region 211a is equal to the number of inductors in region 211b. Also, the number of switch elements in region 211a is equal to the number of switch elements in region 211b. Furthermore, the number of linear regulators in region 211a is equal to the number of linear regulators in region 211b. This prevents heat generated by losses in the inductors, switch elements, and linear regulators from concentrating in certain areas of the imaging power supply board 211, thereby reducing the temperature rise of the imaging sensor 102.

[0162] Although the dividing line 1105 was a dividing line that bisects the area of ​​the imaging power supply board 211, the board may also be divided by dividing lines that divide the board into N equal parts (where N is an integer of 2 or more), so that the number of inductors, switch elements, and linear regulators placed in each divided region is equal. By arranging them in this way, the heat-generating parts are dispersed, and image quality degradation due to temperature rise can be prevented.

[0163] The step-down inductors 1Phasea(3013a) and 1Phaseb(3013b) are arranged such that when a positive current flows in the direction of the imaging sensor 102 (not shown), the direction of the magnetic field generated by step-down inductor 1Phasea(3013a) and the direction of the magnetic field generated by step-down inductor 1Phaseb(3013b) are the same.

[0164] Magnetic fields 1101 and 1103 are arrows indicating the direction of the magnetic field generated from the step-down inductor 1Phasea(3013a) when a positive current flows from the step-down inductor 1Phasea(3013a) toward the imaging sensor 102 (not shown).

[0165] Magnetic fields 1102 and 1104 are arrows indicating the direction of the magnetic field generated from the step-down inductor 1Phaseb(3013b) when a positive current flows from the step-down inductor 1Phaseb(3013b) toward the imaging sensor 102 (not shown).

[0166] When a positive current flows from the step-down inductor 1Phasea(3013a) and the step-down inductor 1Phaseb(3013b) in the direction of the imaging sensor 102 (not shown), magnetic fields 1101 and 1104 are in opposite directions within the winding of the step-down inductor 1Phasea(3013a) and cancel each other out. Similarly, magnetic fields 1103 and 1102 are in opposite directions within the winding of the step-down inductor 1Phaseb(3013b) and cancel each other out.

[0167] As shown in Figure 11, when the step-down inductors 1Phasea (3013a) and 1Phaseb (3013b) are arranged in this manner, the magnetic fields they generate cancel each other out. Therefore, the degradation of image quality due to magnetic noise in the image captured by the imaging sensor 102 can be reduced.

[0168] In Figure 11, magnetic fields 1101 and 1104, and magnetic fields 1103 and 1102 are perpendicular to the image sensor 102 and cancel each other out. However, the step-down inductors 1Phasea (3013a) and 1Phaseb (3013b) may be arranged so that they are parallel to the image sensor 102 and cancel each other out.

[0169] The orientation of the step-down inductors 2Phasea (3113a) and 2Phaseb (3113b) is the same as that of step-down inductors 1Phasea (3013a) and 1Phaseb (3013b).

[0170] (Other embodiments) Furthermore, the present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by a process in which one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0171] The disclosures herein include the following imaging devices:

[0172] (Item 1) An imaging substrate on which an imaging sensor is mounted, A main board that supplies power to the imaging substrate, A flexible circuit board connecting the main board and the imaging board, Equipped with, The main board supplies a first voltage higher than the voltage at which the image sensor operates to the image sensor board via the flexible circuit board, and the image sensor board has a step-down circuit that converts the first voltage to a second voltage lower than the first voltage and outputs it to the image sensor. The imaging apparatus is characterized in that the step-down circuit comprises a switched capacitor that steps down the voltage supplied from the main board to 1 / N (where N is a natural number), and a DC-DC converter including an inductor connected to the switched capacitor.

[0173] (Item 2) The imaging apparatus according to item 1, further comprising control means for controlling the switching frequency of the DC-DC converter according to the operating mode of the imaging sensor.

[0174] (Item 3) The imaging apparatus according to item 2, characterized in that the control means controls the step-down ratio of the switched capacitor according to the switching frequency required by the DC-DC converter.

[0175] (Item 4) The imaging apparatus according to item 2 or 3, characterized in that the control means increases the step-down ratio of the switched capacitor when the voltage supplied to the step-down circuit is the voltage of a DC coupler or USB power supply compared to when the voltage supplied to the step-down circuit is the voltage of a battery.

[0176] (Item 5) The imaging apparatus according to any one of items 1 to 4, characterized in that the DC-DC converter can operate in a mode with a fixed switching frequency.

[0177] (Item 6) The imaging apparatus according to any one of items 1 to 4, characterized in that the DC-DC converter can operate in a mode in which the switching frequency is variable.

[0178] (Item 7) The imaging device according to item 6, characterized in that, in an operating mode in which the image captured by the imaging sensor is not recorded, the switching frequency of the DC-DC converter is reduced.

[0179] (Item 8) The imaging apparatus according to any one of items 1 to 7, characterized in that the imaging substrate comprises a main body of the imaging substrate and an imaging power supply board fixed to the main body of the imaging substrate, and the step-down circuit is arranged on the imaging power supply board.

[0180] (Item 9) The imaging apparatus according to item 8, characterized in that the flexible circuit board connects the main board and the imaging power supply board.

[0181] (Item 10) The main board and the imaging board are connected by a second flexible circuit board, The imaging apparatus according to item 1, characterized in that the main board sends control signals for controlling the imaging sensor to the imaging board via the second flexible circuit board, and receives image data acquired by the imaging sensor via the second flexible circuit board.

[0182] (Item 11) The imaging apparatus according to item 1, characterized in that the imaging sensor is a CMOS image sensor.

[0183] (Item 12) The imaging apparatus according to item 11, characterized in that the imaging sensor is a stacked CMOS image sensor in which a wiring layer for reading out pixel signals is arranged on the back surface of the pixels.

[0184] (Item 13) The imaging apparatus according to item 1, characterized in that the imaging substrate is physically movable for image blur correction.

[0185] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention. [Explanation of symbols]

[0186] 100,200: Imaging device, 101: CPU, 102: Imaging sensor, 105: Temperature sensor, 106: Power control unit, 107: Power supply unit, 108: Battery, 109: Battery monitoring unit, 110: USB power supply unit, 201: Main board, 202: Imaging board

Claims

1. An imaging substrate on which an imaging sensor is mounted, A main board that supplies power to the imaging substrate, A flexible circuit board connecting the main board and the imaging board, Equipped with, The main board supplies a first voltage higher than the voltage at which the image sensor operates to the image board via the flexible circuit board, and the image board has a step-down circuit that converts the first voltage to a second voltage lower than the first voltage and outputs it to the image sensor. The imaging device is characterized in that the step-down circuit includes a switched capacitor that steps down the voltage supplied from the main board to 1 / N (where N is a natural number), and a DC-DC converter including an inductor that is connected to the switched capacitor.

2. The imaging apparatus according to claim 1, further comprising control means for controlling the switching frequency of the DC-DC converter according to the operating mode of the imaging sensor.

3. The imaging apparatus according to claim 2, characterized in that the control means controls the step-down ratio of the switched capacitor according to the switching frequency required by the DC-DC converter.

4. The imaging apparatus according to claim 2, characterized in that the control means increases the step-down ratio of the switched capacitor when the voltage supplied to the step-down circuit is the voltage of a DC coupler or USB power supply compared to when the voltage supplied to the step-down circuit is the voltage of a battery.

5. The imaging apparatus according to claim 1, characterized in that the DCDC converter can operate in a mode with a fixed switching frequency.

6. The imaging apparatus according to claim 1, characterized in that the DCDC converter can operate in a mode with a variable switching frequency.

7. The imaging apparatus according to claim 6, characterized in that, in an operating mode in which the image captured by the imaging sensor is not recorded, the switching frequency of the DC-DC converter is reduced.

8. The imaging apparatus according to claim 1, wherein the imaging substrate comprises a main body of the imaging substrate and an imaging power supply board fixed to the main body of the imaging substrate, and the step-down circuit is arranged on the imaging power supply board.

9. The imaging apparatus according to claim 8, characterized in that the flexible circuit board connects the main board and the imaging power supply board.

10. The main board and the imaging board are connected by a second flexible circuit board, The imaging apparatus according to claim 1, characterized in that the main board sends control signals for controlling the imaging sensor to the imaging board via the second flexible circuit board, and receives image data acquired by the imaging sensor via the second flexible circuit board.

11. The imaging apparatus according to claim 1, characterized in that the imaging sensor is a CMOS image sensor.

12. The imaging apparatus according to claim 11, characterized in that the imaging sensor is a stacked CMOS image sensor in which a wiring layer for reading out pixel signals is arranged on the back surface of the pixels.

13. The imaging apparatus according to claim 1, characterized in that the imaging substrate is physically movable for image blur correction.

Images