Photographing device and control method of the same, program and recording medium

Abstract

To provide a photographing device that can effectively reduce peak currents of a main power source.SOLUTION: A photographing device is provided with: a load circuit; a power source part that supplies electric power to the load circuit; a power storage device part that supplies electric power to the load circuit; an obtaining part that obtains a value of equivalent series resistance of the power storage device part; a control part that controls supply of electric power to the load circuit, which controls the supply so that electric power is supplied from the power source part to the load circuit without making the power storage device part supply electric power to the load circuit, in a first operation state of the photographing device and controls the supply so that electric power is supplied from both the power source part and the power storage device part to the load circuit, in a second operation state of the photographing device in which maximum power consumption by the load circuit is larger than that in the first operation state. The control part changes a limit on a current value of currents that are supplied from the power source part to the load circuit, in accordance with the value of equivalent series resistance of the power storage device part obtained by the obtaining part.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a technology for driving a load circuit using a power storage device in an imaging apparatus. [Background technology]

[0002] An imaging device has been proposed that reduces rolling shutter distortion without using a mechanical shutter by incorporating an imaging sensor that can simultaneously read out multiple pixel data.

[0003] However, the faster the amount of pixel data is read, the higher the peak current of the image sensor becomes. If the peak current increases, the current supplied from the battery of the image sensor will exceed the allowable value, causing the battery voltage to drop and leading to a system shutdown. In addition, when the peak current becomes large, a voltage drop occurs due to line resistance, and the voltage drops below the minimum drive voltage of the image sensor, which may also lead to a system shutdown.

[0004] To avoid this, it is conceivable to stop the operation before the battery voltage falls below a predetermined value in order to avoid a system crash. In this case, however, the operational time of the imaging device will be significantly reduced.

[0005] As a method for dealing with peak currents, a method has been proposed in which the current supplied from a battery is reduced by supplying current from an electricity storage device such as an electric double layer capacitor.

[0006] For example, Patent Document 1 discloses a method for reducing the current when a motor is driven by using an electricity storage device. Patent Document 2 discloses a method for reducing peak current by limiting the current of the main power supply and using an electricity storage device as an auxiliary power supply. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2013-081329 A [Patent Document 2] JP 2008-061492 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, since electric double layer capacitors and other power storage devices are composed of multiple cells connected in series, they may have a high equivalent series resistance (ESR). In addition, due to temperature characteristics, the ESR tends to be large in low temperature environments. Furthermore, when a voltage is applied for a long time in a high temperature environment, the electrical characteristics tend to deteriorate and the ESR tends to increase.

[0009] When the ESR increases, it becomes difficult for the storage device to supply power, and the loss caused by the ESR increases when the storage device is charged or discharged.

[0010] The technique disclosed in the above-mentioned Patent Document 1 has a problem in that when the ESR of the power storage device is high, the current supplied from the power storage device decreases, and the peak current of the battery cannot be reduced sufficiently.

[0011] Furthermore, in the technology disclosed in Patent Document 2, when the current of the main power supply is limited, power is supplied exclusively from the power storage device, which causes the power storage device to be frequently charged and discharged, resulting in an increase in loss due to ESR.

[0012] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an imaging device that can effectively reduce the peak current of the main power supply. [Means for solving the problem]

[0013] The imaging device of the present invention comprises a load circuit, a power supply unit that supplies power to the load circuit, a power storage device unit that supplies power to the load circuit, an acquisition means for acquiring a value of an equivalent series resistance of the power storage device unit, and a control means for controlling the supply of power to the load circuit, the control means controlling the supply of power from the power supply unit to the load circuit without supplying power from the power storage device unit to the load circuit in a first operating state of the imaging device, and controlling the supply of power from the power supply unit and the power storage device unit to the load circuit in a second operating state of the imaging device in which the maximum power consumption of the load circuit is greater than in the first operating state, and is characterized in that the control means changes the limit on the current value of the current supplied from the power supply unit to the load circuit in accordance with the value of the equivalent series resistance of the power storage device unit acquired by the acquisition means. Effect of the Invention

[0014] According to the present invention, it is possible to provide an imaging device that can effectively reduce the peak current of the main power supply. [Brief description of the drawings]

[0015] [Figure 1] 1 is a block diagram showing the configuration of an imaging apparatus according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a block diagram showing the configuration of an imaging power supply unit. [Diagram 3] FIG. 1 is a diagram showing a structure of an imaging device. [Figure 4] FIG. 2 is a diagram showing a more detailed block configuration of an imaging power supply unit. [Figure 5A] 4 is a flowchart showing the operation of an imaging power supply unit. [Figure 5B] 4 is a flowchart showing the operation of an imaging power supply unit. [Figure 5C] 4 is a flowchart showing the operation of an imaging power supply unit. [Figure 6] FIG. 4 is a diagram showing characteristics of the electricity storage device unit. [Figure 7] FIG. 4 is a diagram for explaining determination of a deterioration degree. [Figure 8]FIG. 4 is a diagram showing settings of a main power supply path switching unit and a power storage device charge / discharge unit. [Figure 9] 4 is a timing chart showing state transitions of the imaging device. [Figure 10] FIG. 13 is a diagram showing a notification screen for a user. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0017] FIG. 1 is a block diagram showing the configuration of an image capturing apparatus 100 according to an embodiment of the present invention.

[0018] 1, an imaging drive control unit 1012 receives commands from a control unit 1011 in a CPU 101 that controls the entire imaging device 100, and controls the imaging sensor 102 based on the commands. The imaging sensor 102 controlled in this manner performs photoelectric conversion (exposure) by capturing light from a subject in each pixel, and the signal is converted (read out) into digital data by an A / D converter in the imaging sensor 102.

[0019] Image data generated based on the digital data obtained from each pixel is loaded into a temporary memory 1014 in the CPU 101. In a shooting standby state in which a live view image is to be displayed, data loaded from the imaging sensor 102 is expanded in the temporary memory 1014 in response to a thinning drive command for a live view image from the control unit 1011. The acquired image is corrected by an image correction unit 1015, and then converted into data for display by a display image conversion unit 1016, and displayed on the display unit 103 as a live view image.

[0020] When the user presses the release button, image data is output from the image sensor 102, which is driven and controlled for actual shooting in accordance with instructions from the image capture drive control unit 1012. The image data expanded in the temporary memory 1014 is corrected by the image correction unit 1015, and then JPEG encoding is performed by the image compression unit 1013, and the result is recorded in the recording unit 104 as a still image.

[0021] When the user presses the video recording button, image data is continuously output from the imaging sensor 102, which is driven and controlled for video by instructions from the imaging drive control unit 1012. The image data expanded in the temporary memory 1014 is corrected by the image correction unit 1015, and further subjected to video encoding processing by the image compression unit 1013, and recorded as a video in the recording unit 104. Although not shown in Fig. 1, the imaging device 100 also includes an operation unit for inputting user operations.

[0022] Representative operation modes of the imaging device 100 include a still image mode and a video mode. More specifically, the still image mode includes a single shot mode in which one still image is shot each time the release button is pressed, and a continuous shot mode (continuous shooting mode) in which still images are continuously acquired while the release button is pressed. The continuous shot mode also includes a high-speed continuous shot mode in which more images are shot per unit time, and a low-speed continuous shot mode in which a relatively small number of images are shot per unit time.

[0023] In addition to the single shot mode and continuous shot mode, there is also a high-speed readout mode that obtains still images with reduced distortion of moving subjects by simultaneously reading out a greater number of pixels from the image sensor 102, and a low-speed readout mode that reduces the number of pixels read out simultaneously. Among the high-speed readout modes, there is a global shutter mode that reads out all pixels at once.

[0024] Within the video mode, the operation modes of the imaging device 100 are classified according to the video format used for recording, and include 8K recording mode, 4K recording mode, FHD recording mode, etc. In the video mode, the frame rate can also be changed, and the operation modes of the imaging device 100 are also classified according to the frame rate. The operation mode of the imaging device 100 may be changed in response to a user operation, or may be automatically changed by the control unit to the operation mode that is optimal for the user.

[0025] The power supply unit 107 converts power supplied from a battery 108 or a USB power supply unit 110 into a required voltage and current and supplies it to each block. The battery 108 corresponds to a power supply source for the imaging device 100, and is, for example, a removable lithium ion battery.

[0026] 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 amount of the battery 108. When the remaining capacity of the battery 108 is low or the internal resistance is increasing 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.

[0027] The imaging device 100 can also operate using power supplied from a USB power supply unit 110 instead of the battery 108. The USB power supply unit 110 is, for example, a mobile battery or an AC adapter equipped with a USB cable. In FIG. 1, the power supply unit 107 only includes a CPU power supply unit 1071 that supplies power to the CPU 101 and an imaging power supply unit 1072 that supplies power to the imaging sensor 102, which is a load circuit for the power supply, but also includes power supplies that supply power to the display unit 103, the recording unit 104, and other blocks.

[0028] The power supply control unit 106 controls the power supply unit 107 based on instructions from the control unit 1011. For example, the power supply control unit 106 performs on / off control and changes the output voltage for each power source in the power supply unit 107. Although the power supply control unit 106 is a device separate from the CPU 101 in the description of FIG. 1, the power supply control unit 106 may be configured within the CPU 101. Alternatively, the control unit 1011 may be configured to directly control the power supply unit 107.

[0029] The temperature sensor (temperature detection means) 105 is disposed in the image capturing device 100, and acquires temperature data in the vicinity of the temperature sensor 105. The control unit 1011 can estimate the temperature of any location of the image capturing device 100 based on the output data of the temperature sensor 105. The number of temperature sensors 105 is not limited to one, and the control unit 1011 can also estimate the temperature of the image capturing device 100 in more detail based on the output data of two or more temperature sensors 105.

[0030] The control unit 1011 can change the control of the imaging device 100 in accordance with the temperature information. For example, when 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 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.

[0031] 2 is a block diagram showing the configuration of the imaging power supply unit 1072 in this embodiment. Power supplied from the battery 108 or the USB power supply unit 110 is input to an imaging main power supply unit 201 and a power storage device charge / discharge unit 204. The imaging main power supply unit 201 converts the voltage of the battery 108 into an operating voltage for the imaging sensor 102 and outputs it. The imaging main power supply unit 201 is, for example, a DC / DC converter or an LDO (Low Drop Out) regulator.

[0032] Furthermore, the power storage device charging / discharging unit 204 performs a charging operation to the power storage device unit 202 using power from the battery 108 or the USB power supply unit 110. The power storage device unit 202 is, for example, an electric double layer capacitor (EDLC: Electric Double Layer Capacitor). Alternatively, a power storage device such as an all-solid-state battery may be used as long as it has a large capacity sufficient to cover the driving power of the image sensor 102 and a low equivalent series resistance (ESR: Equivalent Series Resistance) sufficient to accommodate the reaction speed of the image sensor 102. The supply source selection unit 203 selects at least one of the image capture main power supply unit 201 and the power storage device unit 202 to supply power to the image sensor 102.

[0033] The power supply selection unit 203 is controlled by the power supply control unit 106 so that the power of the battery 108 or the USB power supply unit 110 via the imaging main power supply unit 201 is supplied to the imaging sensor 102. However, if the power of the battery 108 or the USB power supply unit 110 is used to cover all the power consumption of the imaging sensor 102, there is a risk that the power will exceed the allowable power of the battery 108 or the USB power supply unit 110. For example, when the operation mode of the imaging device 100 is the global shutter mode, the imaging sensor 102 consumes a large amount of power instantaneously to simultaneously read out all pixels. At this time, there is a high risk that the allowable output current of the battery 108 or the USB power supply unit 110 will be exceeded. Therefore, in the operation mode of the imaging device in which the maximum power is large, such as the global shutter mode, the power supply selection unit 203 is controlled so that the power of the power storage device unit 202 is supplied to the imaging sensor 102. In addition to the global shutter mode, other operating modes with high power consumption that may exceed the allowable current include modes in which multiple pixels are read out simultaneously and modes in which the readout speed is increased for the purpose of high-speed continuous shooting.

[0034] When the imaging sensor 102 consumes power that has been stored in the power storage device unit 202, no instantaneous large current is drawn from the battery 108 or the USB power supply unit 110. In the above description, the output of either the imaging main power supply unit 201 or the power storage device unit 202 is supplied to the imaging sensor 102 by the supply source selection unit 203, but it is not necessarily required to select just one, and power may be supplied to the imaging sensor 102 from both.

[0035] Here, when the power storage device charging / discharging unit 204 performs constant current charging on the power storage device unit 202, the output current of the power storage device charging / discharging unit 204 is kept constant, and the output voltage is made variable in accordance with the increase in voltage of the power storage device unit 202. When the voltage of the power storage device unit 202 reaches a charging completion voltage, the charging operation is stopped.

[0036] At this time, the output voltage and output current of the power storage device charging / discharging unit 204 and the charge completion voltage can be changed by the power supply control unit 106. For example, by setting the output current of the power storage device charging / discharging unit 204 to a large value, it is possible to shorten the time until the power storage device unit 202 is fully charged. On the other hand, if the output current is set to a large value, the amount of power taken from the battery 108 or the USB power supply unit 110 increases. Therefore, in order to reduce the power taken from the battery 108 or the USB power supply unit 110, the output current value of the power storage device charging / discharging unit 204 can be set to a small value.

[0037] Furthermore, by setting the charge completion voltage of the power storage device charge / discharge unit 204 high, more power can be supplied from the power storage device unit 202 to the image sensor 102. On the other hand, if the charge completion voltage is set high, there is a concern that deterioration of the power storage device unit 202 will progress due to a high voltage being applied to the power storage device unit 202 for a long period of time. Therefore, in order to prevent deterioration, the charge completion voltage of the power storage device charge / discharge unit 204 can also be set low.

[0038] In the above, the case where the power storage device charging / discharging unit 204 performs constant current charging on the power storage device unit 202 has been described, but constant voltage charging may also be performed, in which case the upper limits of the charging voltage and charging current can be changed by the power supply control unit 106.

[0039] In addition to the function of charging the power storage device unit 202, the power storage device charge / discharge unit 204 also has a function of discharging the power storage device unit 202 to prevent the power storage device unit 202 from being overcharged.

[0040] Next, FIG. 3 is a diagram illustrating the configuration of the imaging device 100 according to this embodiment.

[0041] 3, main board 301 and image sensor board 302 are disposed within the housing of imaging device 100. CPU 101 and power supply unit 107 are mounted on main board 301. Image sensor 102 is mounted on image sensor board 302, and image sensor board 302 is disposed closer to the lens than main board 301 so that image sensor 102 can efficiently capture light.

[0042] The imaging sensor board 302 is connected to the main board 301 using flexible printed circuits (FPC), a connector, or the like. This allows control signals from the CPU 101 and power from the imaging power supply unit 1072 to be supplied to the imaging sensor 102. The power storage device unit 202 may be mounted on the main board 301 or on the imaging sensor board 302. For example, when it is mounted on the imaging sensor board 302, there is an advantage in that the impedance between the imaging sensor 102 and the power storage device unit 202 is small, making it easier to supply power from the power storage device unit 202 to the imaging sensor 102.

[0043] Moreover, temperature sensor 105a is a temperature sensor arranged on image sensor board 302, temperature sensor 105b is a temperature sensor arranged on main board 301, and temperature sensor 105c is a temperature sensor attached to the housing of image capture device 100. It is possible to estimate the temperature at any point of image capture device 100 based on the output data of these temperature sensors 105a to 105c.

[0044] Since the deterioration of the power storage device unit 202 progresses when exposed to a high-temperature environment, it is important to manage the temperature of the power storage device unit 202. For example, when the power storage device unit 202 is mounted on the imaging sensor board 302, the temperature detected by the temperature sensor 105a is used to monitor the temperature of the imaging sensor 102 so that it does not become outside the usable range. In addition, the temperature detected by the temperature sensor 105a is also used to estimate the temperature of the power storage device unit 202. Also, when the power storage device unit 202 is mounted on the main board 301, for example, the temperature detected by the temperature sensor 105b arranged near the power storage device unit 202 is used to estimate the temperature of the power storage device unit 202. When the temperature sensor 105b cannot be arranged near the power storage device unit 202, the positional relationship between the temperature sensor 105a and the power storage device unit 202, and the temperature detected by the temperature sensor 105a are used to estimate the temperature of the power storage device unit 202 on the main board 301.

[0045] Next, FIG. 4 is a block diagram showing the configuration of the supply source selection unit 203 in this embodiment.

[0046] 4(a) shows the configuration of the power supply source selection unit 203 and its periphery. The power supply source selection unit 203 is configured to be able to switch the impedance of the power supply path (main power path) from the imaging main power supply unit 201 to the imaging sensor 102. The power supply source selection unit 203 is configured to include a main power supply path switching unit 401, a resistor 402, a power storage device path switching unit 403, and a main power supply current detection unit 404. The power supply control unit 106 controls the switching on and off of each switch of the main power supply path switching unit 401 and the power storage device path switching unit 403.

[0047] When the imaging apparatus 100 is in an operating mode in which the maximum power consumption is relatively large, such as the global shutter mode, and during imaging operation, the switch of the power storage device path switching unit 403 is controlled to be turned on. This control causes the power supply path (power storage device path) from the power storage device unit 202 to the imaging sensor 102 to be controlled to be turned on. Before imaging operation, the power storage device unit 202 is charged in advance so that the voltage of the power storage device unit 202 is higher than the voltage of the imaging main power supply unit 201. Therefore, during imaging operation, power can be preferentially supplied from the power storage device unit 202 to the imaging sensor 102.

[0048] However, when power is supplied from the power storage device unit 202 to the image sensor 102, the voltage of the power storage device unit 202 drops. In addition, due to the equivalent series resistance (ESR) of the power storage device unit 202, the voltage of the power storage device unit 202 drops in proportion to the amount of current drawn from the power storage device unit 202.

[0049] 4(a), as an example of a circuit configuration of the power storage device path switching unit 403, a diode is arranged so that the power storage device unit is not charged from the imaging main power supply unit 201 when the power storage device path switch is turned on. Such a component also causes a voltage drop on the power storage device path side.

[0050] When the voltage output from the power storage device path drops, the voltage of the main power path and the voltage of the power storage device path become equal in potential at the junction of the path from the imaging main power supply unit 201 and the path from the power storage device unit 202 via the main power supply path switching unit 401. In this state, power is supplied to the imaging sensor 102 preferentially from the path with the smallest impedance. When the main power supply path switching unit 401 is in the pass-through state and the line impedance of the main power supply path from the imaging main power supply unit 201 is sufficiently low, power is supplied to the imaging sensor 102 preferentially from the imaging main power supply unit 201 even if the power storage device path is on.

[0051] As one means for solving this problem, the switches are switched so as to limit the current on the main power supply path side. Specifically, each switch in the main power supply path switching unit 401 is controlled so that the impedance is larger than the impedance of the power storage device path including the ESR of the power storage device unit 202. In the main power supply path switching unit 401, the switching of each switch is controlled so that any one of the resistors 402a to 402c is arranged in series with the main power supply path. This makes it possible to continue to supply power to the image sensor 102 preferentially from the power storage device unit 202 even if the voltage of the power storage device unit 202 drops.

[0052] Note that, when the power storage device path is turned on while the power storage device unit 202 is charged with a voltage higher than that of the imaging main power supply unit 201, there is a risk of current flowing back into the output of the imaging main power supply unit 201. For this reason, it is desirable that the imaging main power supply unit 201 or the switch arranged in series with the main power supply path be provided with a backflow prevention function.

[0053] The resistor 402 has a resistor 402a with a different resistance value, a resistor 402b larger than the resistor 402a, and a resistor 403c larger than the resistor 402b, and an optimum resistor is selected depending on the situation. In Fig. 4(a), four paths with different impedances are arranged in the main power supply path switching unit 401, but the number is not limited, and the composite impedance of the paths may be changed by a combination of switches that are turned on.

[0054] In order to reduce unnecessary loss caused by the resistor 402, it is desirable for the resistance value of the resistor 402 to be as small as possible, even when it is desired to give priority to the power supply from the power storage device unit 202. Therefore, at the initial stage of any operation mode of the imaging device 100, path A, which has a relatively small resistance value, is turned on.

[0055] However, if the impedance of the power storage device path increases, the impedance of the main power supply path becomes relatively small, and as a result, the necessary power is not supplied from the power storage device unit 202. One example of a case in which the impedance of the power storage device path increases is when the power storage device unit 202 is at a low temperature. When the power storage device unit 202 is in a low temperature state, the ESR tends to increase.

[0056] To address this problem, the control unit 1011 controls the main power supply path switching unit 401 via the power supply control unit 106 based on the temperature detected by the temperature sensor 105, and changes the impedance of the main power supply path. Specifically, the temperature of the power storage device unit 202 is estimated based on the temperature detected by the temperature sensor 105. Control is performed to switch to path B or path C depending on the impedance of the power storage device path expected at the estimated temperature. This allows the power storage device unit 202 to supply the necessary power even if the impedance of the power storage device path increases at low temperatures.

[0057] When the path A is set to the first supply mode, the path B or the path C, which further limits the current, is called the second supply mode. Although the present embodiment describes switching between three paths, it is acceptable to switch between two or more supply modes.

[0058] A possible cause of an increase in the impedance of the power storage device path is an increase in the ESR of the power storage device section 202 due to degradation, in addition to the temperature characteristics of the power storage device section 202. For this reason, it is desirable to measure the impedance of the power storage device path. The impedance of the power storage device path can be calculated by detecting the current of the main power supply path. For this purpose, the supply source selection section 203 includes a main power supply current detection section 404.

[0059] The main power supply current detection unit 404 can calculate the current flowing through the main power supply path from the voltage difference across the resistor 402. If the current at the time of reading out the image sensor 102 is known to be, for example, 3 A, and if the current flowing through the main power supply path is 1 A, then 2 A will flow through the power storage device path. This current ratio is determined by the ratio of the impedance of the main power supply path to the impedance of the power storage device path. If the main power supply path at this time is path A, then the impedance of the power storage device path can be calculated as 1 / 2 of the resistor A. Depending on the impedance of the power storage device path calculated in this manner, control is performed to switch to path B or path C. This makes it possible to ensure that the necessary power is supplied from the power storage device unit 202 even if the power storage device unit 202 deteriorates and the impedance of the power storage device path increases.

[0060] In addition to the method of measuring the impedance of the power storage device path by detecting the current of the main power supply path, for example, a power storage device path impedance calculation means may be arranged in a switch in the power storage device path switching unit 403. The impedance of the power storage device path can be measured from the current and voltage flowing through the power storage device path. In another example, a power storage device path impedance calculation means may be arranged in the power storage device charging / discharging unit 204. The impedance of the power storage device path can be measured from the amount of voltage drop in the power storage device unit 202 when discharging at a constant current.

[0061] Increasing the impedance of the main power path also has the disadvantage of increasing the loss in the main power path. Furthermore, when the power storage device path is on, the power storage device unit 202 supplies power to the image sensor 102 regardless of whether or not power needs to be supplied from the power storage device unit 202 to the image sensor 102. This causes unnecessary charging and discharging in the power storage device unit 202, resulting in a decrease in the battery life of the battery 108.

[0062] Therefore, in an operation mode in which the maximum power of the imaging device 100 is relatively small and the imaging device 100 operates within the allowable power of the battery 108 or the USB power supply unit 110, the main power path switching unit 401 is controlled to reduce the impedance of the main power path. This makes it possible to minimize loss in the main power path. In addition, because the impedance of the main power path is reduced, when the voltage of the main power path and the voltage of the power storage device path become the same potential, power is supplied from the imaging main power supply unit 201 to the imaging sensor 102. As a result, unnecessary charging and discharging of the power storage device unit 202 is reduced, and the battery life of the battery 108 can be improved.

[0063] In addition, the power storage device path switching unit 403 may be switched off at the same time as the main power supply path is switched, and the power storage device path may be turned off. This allows the image sensor 102 to operate without consuming the power stored in the power storage device unit 202, and further prevents loss due to unnecessary charging and discharging of the power storage device unit 202.

[0064] The above-mentioned operating modes with relatively low power consumption include, for example, a moving image mode, a single shot mode, a low-speed continuous shooting mode, a low-speed readout mode, etc. among still image modes. In addition, operating modes with relatively high maximum power consumption of the imaging device 100 include, for example, a global shutter mode, a high-speed continuous shooting mode, and a live view state in a high-speed readout mode.

[0065] The main power path switching unit 401 may be configured to be controlled to switch the main power path between a read operation of the image sensor 102 and other periods, regardless of the operation mode of the imaging device 100. For example, the impedance of the main power path is controlled to be high in synchronization with the read operation of the image sensor 102, and low in periods other than readout. By controlling in this manner, it is possible to reduce the current drawn from the battery 108 or the USB power supply unit 110 during a read operation, and to reduce unnecessary loss in periods other than readout.

[0066] FIG. 4B shows a configuration in which the main power path switching unit 401 is replaced with a main power current limiting unit 406. The main power current limiting unit 406 limits the current output from the main power current limiting unit 406 so as not to exceed a current threshold value determined by the power control unit 106. FIG. 4B shows an example in which the main power current limiting unit 406 is a component of the power supply source selection unit 203, but the imaging main power unit 201 may have a function equivalent to that of the main power current limiting unit 406. As with the main power path switching unit 401 shown in FIG. 4A, the main power current limiting unit 406 can change the limit current based on information from a temperature sensor. As with the main power path switching unit 401 shown in FIG. 4A, the current threshold value can also be changed depending on the operation mode of the imaging device 100.

[0067] A state in which the current output from the main power path is controlled to a first value is called a first supply mode, and a state in which the current output from the main power path is controlled to a second value lower than the first value is called a second supply mode. The first supply mode can also be said to be a state in which the current limit on the main power path is weak. The second supply mode can also be said to be a state in which the current limit on the main power path is strong. As described above, the first supply mode and the second supply mode are switched depending on the operation mode of the imaging device 100. Also, the control of switching between the first supply mode and the second supply mode depending on the information of the temperature sensor 105 has been described. Also, the control of the control unit 1011 switching between the first supply mode and the second supply mode depending on the ESR has been described. Such a switching operation makes it possible to suppress loss in the imaging power supply unit 1072 while reducing the maximum current of the battery 108 or the USB power supply unit 110.

[0068] Note that a state in which the current of the main power path is not limited and a state in which the current is limited may be switched as a first supply mode and a second supply mode, or the supply mode may be switched so as to have two or more different limit values.

[0069] Also, the state of the battery 108 may be monitored by the battery monitoring unit 109 shown in FIG. 4B, and the supply mode may be switched depending on the state of the battery 108. For example, when the voltage of the battery 108 is lower than a predetermined value, the second supply mode is selected. In another example, when the current of the battery 108 is greater than a predetermined value, the second supply mode is selected. In another example, when the internal resistance of the battery 108 is greater than a predetermined value, the second supply mode is selected. In this way, the output current of the imaging main power supply unit 201 is limited so as not to exceed the allowable current of the battery 108, and the imaging sensor 102 can be operated in combination with the power from the power storage device unit 202.

[0070] 4(a) and 4(b), a configuration has been described in which the impedance of the main power supply path is changed depending on the temperature or ESR of the power storage device unit 202. Here, when the power storage device unit 202 is in an excessively low temperature state, even if the impedance of the main power supply path is set to the maximum, the impedance of the power storage device path becomes larger than the maximum, so power is preferentially supplied from the imaging main power supply unit 201 to the imaging sensor 102. At this time, there is a risk that the allowable power of the battery 108 or USB power supply unit 110 will be exceeded, causing a system shutdown.

[0071] To solve this problem, the control unit 1011 predicts the power to be supplied from the imaging main power supply unit 201 to the imaging sensor 102 based on information from the temperature sensor 105, and controls the imaging device 100 to prohibit shooting operations if the power exceeds a predetermined value.

[0072] Furthermore, if the impedance of each path serving as the power supply path for the image sensor 102 becomes excessively large, there is a risk that the voltage will fall below the operating voltage of the image sensor 102 due to a voltage drop caused by the impedance.

[0073] To solve this problem, the control unit 1011 predicts the voltage drop of the image sensor 102 from information from the temperature sensor 105, and controls the image capturing device 100 to prohibit shooting operations if the voltage drop exceeds a predetermined value.

[0074] In the above example, the control unit 1011 has been described as prohibiting the image capturing operation of the imaging device 100 based on information from the temperature sensor 105, but the control unit 1011 may also predict the ESR of the power storage device unit 202 and prohibit the image capturing operation. In this case, the control unit 1011 predicts the power to be supplied from the imaging main power supply unit 201 to the image capturing sensor 102 from the ESR of the power storage device unit 202, and performs control to prohibit the image capturing operation of the imaging device 100 if the power exceeds a predetermined value. The control unit 1011 also predicts the voltage drop of the image capturing sensor 102 from the ESR of the power storage device unit 202, and performs control to prohibit the image capturing operation of the imaging device 100 if the voltage drop exceeds a predetermined value.

[0075] For example, in the case where the still image mode has a higher maximum power than the video mode and is based on the assumption that the power of the power storage device unit 202 is supplied to the imaging sensor 102, shooting operations in only the still image mode are prohibited when the power storage device unit 202 falls into the above-mentioned state. Alternatively, even in the still image mode, shooting operations in the high-speed continuous shooting mode, high-speed readout mode, and global shutter mode, which are based on the assumption that more power is supplied from the power storage device unit 202 to the imaging sensor 102, may be prohibited.

[0076] Next, FIGS. 5A to 5C are flowcharts showing the control of the imaging power supply unit 1072 by the control unit 1011 via the power supply control unit 106 in this embodiment.

[0077] For example, when a user performs an operation such as pressing the power button of the imaging device 100, in step S501, the control unit 1011 performs a startup process of the imaging device 100. In the startup process of the imaging device 100, a start-up operation of the power supply unit 107 is performed.

[0078] Next, in step S502, the control unit 1011 performs an initialization process of the main power supply path switching unit 401. In the initialization process, the control unit 1011 controls the main power supply path to be in a pass-through state. This makes it possible to prevent unnecessary loss from occurring in the resistor 402 in the live view state.

[0079] Next, in step S503, the control unit 1011 disables the power storage device path. It controls the power storage device path switching unit 403 to turn off the switch so that power is not supplied from the power storage device unit 202 to the image sensor 102. This prevents loss due to unnecessary charging and discharging of the power storage device unit 202 in the live view state.

[0080] Next, in step S504, the control unit 1011 performs imaging startup processing and starts operation in a live view state. In this live view state, power is supplied from the imaging main power supply unit 201 to the imaging sensor 102 via a pass-through path.

[0081] Next, in step S505, the control unit 1011 predicts the ESR of the power storage device unit 202. First, the control unit 1011 controls the main power path to be path B. The control unit 1011 also controls the power storage device path switching unit 403 to be switched on so as to enable the power storage device path. At the same time, the power storage device charging / discharging unit 204 charges the power storage device unit 202 so that the output voltage is higher than the output voltage of the imaging main power supply unit 201. Next, the imaging sensor 102 is caused to operate so that the current consumption is known and constant. At this time, the main power supply current detection unit 404 detects the current flowing in the main power supply path from the voltage difference across the resistor 402a. The detected main power supply path current is transmitted to the control unit 1011. The control unit 1011 calculates the current in the power storage device path using the following formula.

[0082] Power storage device path current = Image sensor current consumption - Main power path current (Equation 1) Next, the ESR of the power storage device section 202 is predicted by the following formula using the ratio of the power storage device path current to the main power supply path current.

[0083] Storage device ESR = Resistance B × (Main power supply path current / power storage device path current) (Equation 2) By detecting the current in the main power supply path in this manner, it is possible to predict the ESR of the power storage device section 202.

[0084] Although the current consumption of the image sensor 102 is used to predict the ESR of the power storage device section 202, a dedicated test circuit that generates a load with a known current consumption may be provided separately from the image sensor. Also, a method of using current detection of the main power supply path to predict the ESR of the power storage device section 202 has been described, but the ESR prediction is not limited to the above means and formula, and may be performed using other means and formulas.

[0085] When the prediction of the ESR of the power storage device unit 202 is completed, the switch is controlled to put the main power path into a pass-through state and to disable the power storage device path.

[0086] Next, in step S506 , the control unit 1011 estimates the temperature of the power storage device unit 202 based on the output data of the temperature sensor 105 .

[0087] Next, in step S507, the control unit 1011 determines whether the power storage device unit 202 has deteriorated.

[0088] 6 and 7 are diagrams for explaining the deterioration determination of the power storage device unit 202. FIG.

[0089] FIG. 6(a) shows the temperature characteristics of the power storage device unit 202. The power storage device unit 202 exhibits a characteristic in which the ESR increases as the temperature decreases. Also, FIGS. 6(b) and 6(c) show the degradation characteristics of the power storage device unit 202. Even with the same applied voltage, the higher the temperature, the more the degradation progresses, and the ESR increases as a result of the degradation. Also, even with the same temperature, the higher the applied voltage, the more the degradation progresses, and the ESR increases as a result of the degradation. In other words, simply identifying the ESR does not tell whether it is due to the temperature characteristics of the power storage device unit 202 or the result of the progression of degradation.

[0090] 7 is a diagram showing regions for each degree of deterioration of the power storage device unit 202, and the control unit 1011 performs a deterioration judgment of the power storage device unit 202 based on this diagram. When the temperature is high, the ESR of the power storage device unit 202 tends to be small, but if the ESR is large despite this, this is because deterioration is progressing. Also, when the temperature is low, the ESR of the power storage device unit 202 tends to be high, so even if the ESR is somewhat large, it can be judged that this is due to temperature characteristics.

[0091] 7, using the ESR and temperature information acquired in steps S505 and S506, and thereby calculates the degree of deterioration. As another example, an ESR deterioration degree threshold may be set for each temperature, and the degree of deterioration may be calculated by comparing the acquired ESR with the ESR deterioration degree threshold.

[0092] Next, in step S508, the control unit 1011 determines whether or not the operation mode of the imaging device 100 is the moving image mode. If the operation mode of the imaging device 100 is the still image mode, the process proceeds to step S509. If the operation mode of the imaging device 100 is the moving image mode, the process proceeds to step S528.

[0093] Here, the video mode is an example of a mode in which the maximum power required for shooting in that operating mode can be fully covered by the power supplied by the battery 108 or the USB power supply unit 110. In the case of a relatively low-power mode among still image modes, such as the low-speed continuous shooting mode or the low-speed readout mode, the process may proceed to step S528 instead of step S509.

[0094] In step S509, the control unit 1011 determines whether the power storage device unit 202 is usable or not by referring to the degree of deterioration of the power storage device unit 202 determined in step S507.

[0095] When the deterioration degree of the power storage device unit 202 is extremely advanced, shooting is prohibited. This is because it is predicted that the system will fall into a state in which it cannot be established even if the main power path switching unit 401 is controlled so that the impedance of the main power path is maximized. For example, this state is a state in which a large amount of power is supplied from the imaging main power supply unit 201 to the imaging sensor 102, so that the allowable power of the battery 108 or the USB power supply unit 110 is exceeded, causing a system down. In another case, the impedance of each path that serves as the power path of the imaging sensor 102 is large, so that the voltage drop due to the impedance is predicted to cause the voltage to fall below the operating voltage of the imaging sensor 102. If the deterioration degree is such that such a state actually occurs, proceed to step S529. If the deterioration degree is other than the above, proceed to step S510.

[0096] In step S510, the control unit 1011 determines the temperature of the power storage device unit 202. The control unit 1011 compares the estimated temperature of the power storage device unit 202 acquired in step S506 with the temperature (Ta) at which degradation of the power storage device unit 202 progresses rapidly. If the estimated temperature of the power storage device unit 202 is lower than Ta, that is, if there is a low risk that degradation of the power storage device unit 202 will progress even if a high voltage is applied to the power storage device unit 202, the control unit 1011 proceeds to step S511. If the estimated temperature of the power storage device unit 202 is higher than Ta, that is, if there is a high risk that degradation of the power storage device unit 202 will progress if a high voltage is continued to be applied to the power storage device unit 202, the control unit 1011 proceeds to step S511.

[0097] In step S511, the control unit 1011 changes the charging voltage at which the power storage device charging / discharging unit 204 charges the power storage device unit 202. If the power storage device charging / discharging unit 204 charges the power storage device unit 202 by constant current charging, the charge completion voltage is changed. In step S511, since the temperature of the power storage device unit 202 is high and there is a high risk of deterioration, the charging voltage is set low. In this way, by lowering the charging voltage of the power storage device unit 202 based on information from the temperature sensor 105, deterioration of the power storage device unit 202 can be suppressed. Next, the process proceeds to step S513.

[0098] In step S512, the control unit 1011 changes the charging voltage for charging the power storage device unit 202 from the power storage device charging / discharging unit 204, as in step S511. In step S512, the charging voltage is set high because the temperature of the power storage device unit 202 is low and the risk of deterioration is low. If the operation mode of the imaging device 100 is an operation mode that assumes that power is supplied from the power storage device unit 202 to the imaging sensor 102, it is necessary that a predetermined voltage that is at least higher than the output voltage of the imaging main power supply unit 201 is reached at the time of shooting. Therefore, in a state where the temperature is low and there is little concern about deterioration, by keeping the charging voltage of the power storage device unit 202 high, it is possible to smoothly transition to the shooting operation without taking unnecessary charging time during shooting. Next, the process proceeds to step S513.

[0099] In step S513, the control unit 1011 changes the charging current for charging the power storage device unit 202 from the power storage device charging / discharging unit 204. When the power storage device charging / discharging unit 204 charges the power storage device unit 202 with constant current charging, the output current of the power storage device charging / discharging unit 204 is changed. The power storage device charging / discharging unit 204 can be set to a high output mode with a relatively large output current and a low output mode with a relatively small output current. In step S513, the power storage device charging / discharging unit 204 is set to the high output mode. As a result, for example, when the operation mode of the imaging device 100 is set to a video mode and the charging voltage of the power storage device unit 202 is low from the viewpoint of preventing deterioration, it is possible to charge at high speed up to the target charging voltage when the operation mode is changed to a still image mode. Also, during this timing from the mode switching to the start of shooting, the current consumption of the imaging device 100 is relatively small, and there is a margin in the allowable power of the battery 108 or the USB power supply unit 110. Therefore, there is no problem even if the power storage device charge / discharge unit 204 is put into the high output mode at this timing.

[0100] Next, in step S514, the control unit 1011 determines whether or not SW1 has been pressed by the user. SW1 corresponds to the operation immediately before the user's release operation, such as half-pressing the release button. When SW1 is pressed, the imaging device 100 is in a shooting preparation state in which it can immediately move to shooting operation when SW2 is pressed. In response to the SW1 operation, a known shooting preparation process such as AF processing or AE processing is executed. If SW1 is not pressed, the process proceeds to step S515. If SW1 is pressed, the process proceeds to step S516.

[0101] In step S515, the control unit 1011 determines whether or not a user operation corresponding to a change in the operation mode of the imaging device 100 has been performed. If the operation mode of the imaging device 100 has not been changed, the process returns to step S514. If the operation mode of the imaging device 100 has been changed, the process returns to step S505. If the user has performed an operation to shut down the imaging device 100, such as turning off the main power switch, the process proceeds to step S531.

[0102] In step S516, the control unit 1011 sets the charging voltage of the power storage device unit 202 to a voltage that allows power to be supplied from the power storage device unit 202 to the imaging sensor 102. At this time, if the charging voltage is set in step S512 to the same voltage as the charging voltage of the power storage device unit 202 set in step S516, there is no need to reset the charging voltage of the power storage device unit 202 in step S516. If the charging voltage of the power storage device unit 202 is set low in step S511 to prevent deterioration, the charging voltage of the power storage device unit 202 is set in step S516 to a voltage that allows power to be supplied from the power storage device unit 202 to the imaging sensor 102. This enables image capture while minimizing the time for which the voltage is increased and preventing deterioration, even when the temperature of the power storage device unit 202 is high.

[0103] Next, in step S517, the control unit 1011 determines whether charging of the power storage device unit 202 is complete. The control unit 1011 compares the voltage set in step S516 with the voltage of the power storage device unit 202 to determine whether charging is complete. Alternatively, the control unit 1011 may monitor the charging current and determine whether charging of the power storage device unit 202 is complete based on whether the charging current has stopped. If charging of the power storage device unit 202 is not yet complete, the process proceeds to step S518. If charging of the power storage device unit 202 is complete, the process proceeds to step S519.

[0104] In step S518, the control unit 1011 displays a busy message in addition to the live view display. The busy message here means that the imaging device 100 is unable to perform an image capturing operation. The user can know whether or not image capturing is possible by checking the busy message. After the busy message is displayed, the process returns to step S517. This is repeated until charging of the power storage device unit 202 is complete, and if it is determined in step S517 that charging of the power storage device unit 202 is complete, the busy message is cancelled.

[0105] In step S519, the control unit 1011 determines whether or not SW2 has been pressed by the user. SW2 corresponds to the user's operation to instruct release, such as the full press of the release button. If SW2 has not been pressed, the process proceeds to step S527. If SW2 has been pressed, the process proceeds to step S520.

[0106] In step S520, the control unit 1011 changes the charging current used to charge the power storage device unit 202 from the power storage device charging / discharging unit 204. When the power storage device charging / discharging unit 204 charges the power storage device unit 202 with a constant current charge, the output current of the power storage device charging / discharging unit 204 is changed. In step S520, the power storage device charging / discharging unit 204 is set to a low output mode. This makes it possible to reduce the power taken from the battery 108 or the USB power supply unit 110 during shooting operation. In the low output mode, a charging current is desirable that allows the voltage of the power storage device unit 202, which has dropped in a high-speed continuous shooting mode with a short shooting interval, to recover within the time until the next shooting operation.

[0107] Next, in step S521, the control unit 1011 sets the main power path to a path other than the pass-through state. Here, the control unit 1011 determines the main power path according to the output data of each of the temperature sensors 105a to 105c. The lower the temperature of the power storage device unit 202, the higher the ESR of the power storage device unit 202. Therefore, by controlling the impedance of the main power path to be higher as the temperature decreases, it becomes possible to supply power from the power storage device unit 202 to the image sensor 102 regardless of the temperature of the imaging device 100. The ESR of the power storage device unit 202 also increases due to deterioration. Therefore, the main power path may be changed according to the ESR of the power storage device unit 202 predicted in step S505. When the ESR is within the allowable range of deterioration, it becomes possible to supply power from the power storage device unit 202 to the image sensor 102 regardless of the value of the ESR.

[0108] Next, in step S522, the control unit 1011 enables the power storage device path. It controls the power storage device path switching unit 403 to turn on the switch so that power is supplied from the power storage device unit 202 to the image sensor 102. This makes it possible to supply power from the power storage device unit 202 to the image sensor 102 during image capture.

[0109] Next, in step S523, the control unit 1011 performs an image capturing operation. First, since the voltage of the power storage device unit 202 is higher than the voltage of the imaging main power supply unit 201, power is supplied from the power storage device unit 202 to the imaging sensor 102. When the voltage of the power storage device unit 202 drops and becomes the same as the voltage of the imaging main power supply unit 201, power is supplied to the imaging sensor 102 from the path with the smaller impedance between the main power supply path and the power storage device path. In step S521, since the impedance of the power storage device path is controlled to be smaller than that of the main power supply path, even if the voltage of the power storage device unit 202 drops, power is preferentially supplied from the power storage device unit 202 to the imaging sensor 102. As a result, even when the imaging apparatus 100 is in an image capturing state in an operation mode with a large maximum power such as a global shutter mode, it is possible to reduce the instantaneous power drawn from the battery 108 or the USB power supply unit 110.

[0110] Next, in step S524, the control unit 1011 determines whether SW2 has been released. If SW2 continues to be pressed, the process returns to step S523 to perform the next shooting operation. If SW2 has been released, the shooting operation is stopped and the process proceeds to step S525.

[0111] In step S525, the control unit 1011 performs the initialization process of the main power path switching unit 401 in the same manner as in step S502.

[0112] Next, in step S526, the control unit 1011 invalidates the power storage device path in the same manner as in step S503.

[0113] Next, in step S527, the control unit 1011 determines whether SW1 has been released. If SW1 continues to be pressed, the process returns to step S519 to determine whether SW2 is pressed again. If SW1 is released and then SW2 is released, the shooting preparation state is stopped and the process returns to step S510.

[0114] In step S528, the control unit 1011 sets the charging voltage of the power storage device unit 202 low. For example, in an operation mode such as a video mode in which the power supplied by the battery 108 or the USB power supply unit 110 can sufficiently cover the maximum power of the image sensor 102, the charging voltage of the power storage device unit 202 is set low even during shooting. This makes it possible to prevent deterioration of the power storage device unit 202. In particular, when the operation mode of the imaging device 100 given as an example is a video mode, shooting is often continued for a long period of time, which causes the internal temperature of the imaging device 100 to rise, and the temperature of the power storage device unit 202 to also rise. In an operation mode in which the temperature of the power storage device unit 202 is likely to rise, it is important to set the charging voltage of the power storage device unit 202 low in order to prevent deterioration. Even if the charging voltage of the power storage device unit 202 is set low here, when switching to the still image mode, the charging current is increased in step S513 to charge the power storage device unit 202 at high speed. Therefore, it is possible to quickly transition to the shooting operation. Next, proceed to step S530.

[0115] In step S529, the control unit 1011 displays on the display unit 103 to the user that the current operation mode cannot be used due to deterioration of the power storage device unit 202. This allows the user to know that this mode is not available and that the power storage device unit 202 has deteriorated. For example, if the user who sees this wants to continue using this operation mode, he or she can take measures such as replacing the power storage device unit 202. Also, in step S529, a display may be displayed to guide the user to an alternative mode that can be used, thereby enabling the user to continue shooting in the alternative mode. Next, the process proceeds to step S530.

[0116] In step S530, the control unit 1011 determines whether or not a user operation corresponding to a change in the operation mode of the imaging device 100 has been performed, similarly to step S515. If the operation mode of the imaging device 100 has not been changed, S530 is repeated while maintaining the live view state, and a mode change is awaited. If the operation mode of the imaging device 100 has been changed, the process returns to step S505. If the user has performed an operation to shut down the imaging device 100, such as turning off the main power switch, the process proceeds to step S531.

[0117] In step S531, the control unit 1011 sets the charging voltage of the power storage device 202 to 0 V. This makes it possible to suppress deterioration of the power storage device unit 202 when the imaging apparatus 100 is powered off.

[0118] Next, in step S532, the control unit 1011 performs a process of shutting down the imaging device 100. In the process of shutting down the imaging device 100, in addition to the process of shutting down each device, the power supply unit 107 is also shut down.

[0119] For example, in the case where the target voltage of the power storage device unit 202 becomes lower than the current voltage in step S511, step S528, or step S531, the output of the power storage device charging / discharging unit 204 may be stopped and the target voltage may be waited for by natural discharge. In this case, the frequency of the power once stored in the power storage device 202 becoming invalid is reduced, which is advantageous for the battery life of the battery 108. On the other hand, the time for which the voltage is applied is extended, which may cause deterioration. For this reason, the power storage device charging / discharging unit 204 may be provided with a discharge function and may perform discharging until the target voltage is reached. In this case, the voltage of the power storage device unit 202 is quickly reduced, so deterioration of the power storage device unit 202 can be suppressed.

[0120] 8(a) and (b) are diagrams illustrating an example of switch settings of the main power supply path switching unit 401.

[0121] Here, the still image mode requires a relatively large maximum power, and is based on the premise that the imaging sensor 102 is operated with power supplied from the power storage device unit 202. On the other hand, the moving image mode requires a relatively small maximum power, and is based on the premise that the imaging sensor 102 is operated without power being supplied from the power storage device unit 202 to the imaging sensor 102. Among the still image modes, the global shutter mode in particular requires a large maximum power, and is based on the premise that the imaging device 100 is operated with more power supplied from the power storage device unit 202.

[0122] FIG. 8A is a switch setting table for the main power path switching unit 401 when switching the main power path depending on the temperature.

[0123] When the temperature is 20°C or higher, in global shutter mode, path B and path C are turned on. At this time, the impedance of the main power supply path becomes a composite resistance of resistor 402b and resistor 402c arranged in parallel. Also, in still image modes other than global shutter mode, path A and path C are turned on. At this time, the impedance of the main power supply path becomes a composite resistance of resistor 402a and resistor 402c arranged in parallel. And even in video mode or still image mode, in the live view state, the pass-through state is set.

[0124] In this way, the more power is supplied from the power storage device unit 202 to the image sensor 102 in an operation mode, the higher the current limit on the main power supply path is set. Conversely, in an operation mode in which little power supply from the power storage device unit 202 is required, the limit on the main power supply path is relaxed so that more power than necessary is not supplied from the power storage device unit 202, thereby making it possible to reduce loss in the main power supply path. In addition, it is possible to reduce loss due to charging and discharging the power storage device unit 202.

[0125] Furthermore, when the temperature is less than 20°C and equal to or higher than 0°C, the switch state is changed so as to increase the impedance of the main power supply path in each mode. This is because the ESR of the power storage device unit 202 rises in a low temperature state, and by increasing the impedance of the main power supply path, it is possible to supply power from the power storage device unit 202 to the image sensor 102. Conversely, when the temperature is sufficiently high, it is possible to reduce the loss in the main power supply path and the loss due to charging and discharging the power storage device unit 202 by relaxing the restrictions on the main power supply path. Furthermore, even in video mode or still image mode, since it is assumed that the image sensor 102 will be operated without being supplied with power from the power storage device unit 202 in the live view state, the pass-through state is fixed regardless of the temperature.

[0126] Similarly, when the temperature is below 0°C, the switch state is changed so as to further increase the impedance of the main power path in each mode.

[0127] FIG. 8B is a switch setting table for the main power path switching unit 401 when the main power path is switched based on the ESR of the power storage device unit 202.

[0128] When estimating the ESR of the power storage device section 202, path B is turned on regardless of the operating mode or other settings of the imaging apparatus 100. The control section 1011 can predict the ESR of the power storage device section 202 from the known resistance B and the operating power of the imaging sensor, as well as information from the main power supply current detection section 404 when the imaging sensor is operated. Depending on the predicted ESR, the switch state of the main power supply path switching section 401 is changed during imaging.

[0129] When the ESR of the power storage device unit 202 is less than 100 mΩ, the path B and the path C are turned on in the global shutter mode. At this time, the impedance of the main power supply path is a composite resistance of the resistor 402b and the resistor 402c arranged in parallel. Also, in a still image mode other than the global shutter mode, the path A and the path C are turned on. At this time, the impedance of the main power supply path is a composite resistance of the resistor 402a and the resistor 402c arranged in parallel. And, even in the video mode or the still image mode, in the live view state, the pass-through state is set. In this way, the more power is supplied from the power storage device unit 202 to the image sensor 102 in the operation mode, the higher the current limit of the main power supply path is. Conversely, in an operation mode in which the power supply from the power storage device unit 202 is not required much, the limit of the main power supply path is relaxed so that the power is not supplied from the power storage device unit 202 more than necessary, thereby making it possible to reduce the loss of the main power supply path. In addition, it is possible to reduce the loss due to the charging and discharging of the power storage device unit 202.

[0130] Furthermore, when the ESR of the power storage device unit 202 is equal to or greater than 100 mΩ and less than 400 mΩ, the switch state is changed so as to increase the impedance of the main power supply path in each mode. Since the ESR of the power storage device unit 202 is increased, the impedance of the main power supply path is increased so that power can be supplied from the power storage device unit 202 to the image sensor 102. In other words, when the ESR of the power storage device unit 202 is sufficiently low, it is possible to reduce the loss in the main power supply path and the loss due to charging and discharging the power storage device unit 202 by relaxing the restrictions on the main power supply path. Furthermore, even in the video mode or still image mode, since it is assumed that the power storage device unit 202 will operate without supplying power to the image sensor 102 in the live view state, the state is fixed to the pass-through state regardless of the ESR of the power storage device unit 202.

[0131] Similarly, when the ESR of the power storage device section 202 is equal to or greater than 400 mΩ and less than 600 mΩ, the switch state is changed so as to further increase the impedance of the main power supply path in each mode.

[0132] When the ESR of the power storage device unit 202 becomes 600 mΩ or more, shooting in the global shutter mode is prohibited. This is because it is predicted that the system will not function even if only the path C is turned on so that the impedance of the main power path is maximized. For example, this situation is a situation in which a large amount of power is supplied from the imaging main power supply unit 201 to the imaging sensor 102, exceeding the allowable power of the battery 108 or the USB power supply unit 110 and causing a system down. In another case, the impedance of each path that serves as the power path for the imaging sensor 102 is large, and it is predicted that the voltage will fall below the operating voltage of the imaging sensor 102 due to a voltage drop caused by the impedance. Before such a predicted situation actually occurs, it is possible to prohibit shooting operations according to the ESR.

[0133] FIG. 8(c) is a diagram illustrating settings of the power storage device charging / discharging unit 204 in each operation mode.

[0134] During image capture in global shutter mode, the charging voltage of the power storage device unit 202 is set to 5.0 V. For example, if the output voltage of the imaging main power supply unit 201 is 4.5 V, the voltage of the power storage device path will be higher than that of the main power supply path, so that power is supplied preferentially from the power storage device unit 202 to the imaging sensor 102. Also, in the case of a live view state, if the estimated temperature of the power storage device unit 202 is higher than Ta, the charging voltage is lowered to 2.0 V. This makes it possible to suppress deterioration of the power storage device.

[0135] If the charging voltage is set to 0V, if the user performs an operation to start shooting in this state, it will take time to charge from 0V to 5.0V, which will result in a long period of time during which the user cannot shoot. To solve this problem, charging is performed within a range in which deterioration does not progress significantly even when the temperature is higher than Ta. Also, when the estimated temperature of the power storage device unit 202 is lower than Ta, the voltage is lowered to about 4.5V in order to prevent deterioration. The time required to charge from 4.5V to 5.0V is short, and it is considered that this has almost no impact on the user.

[0136] During shooting in a still image mode other than the global shutter mode, the charging voltage of the power storage device unit 202 is set to 4.5 V. In a still image mode other than the global shutter mode, less power needs to be supplied from the power storage device unit 202 to the image sensor 102 than in the global shutter mode, so the charging voltage of the power storage device unit 202 is set lower than in the global shutter mode. In this way, setting the charging voltage of the power storage device unit 202 to an optimal voltage depending on the operation mode is important in terms of suppressing deterioration of the power storage device unit 202. Furthermore, in the case of a live view state, when the estimated temperature of the power storage device unit 202 is higher than Ta, the charging voltage is lowered to 2.0 V, as in the case of the global shutter mode.

[0137] In the case of video mode, regardless of whether the camera is in shooting mode or in live view mode, the charging voltage of the power storage device unit 202 is set to a uniform 2.0 V. In this manner, in a mode that is premised on operation without supplying power from the power storage device unit 202 to the image sensor 102, deterioration of the power storage device unit 202 can be suppressed by lowering the charging voltage of the power storage device unit 202. The reason why the charging voltage of the power storage device unit 202 is not set to 0 V here is to shorten the charging time of the power storage device unit 202 as much as possible when the user switches to still image mode and immediately attempts to start shooting.

[0138] Furthermore, when measuring the ESR, the charging voltage of the power storage device unit 202 is set to 4.5 V. Here, the setting of 4.5 V means a voltage setting that is approximately the same as the output voltage of the imaging main power supply unit 201, and this makes it possible to calculate the impedance ratio of each path from the current ratio of each path.

[0139] Furthermore, when the power supply of the imaging device 100 is turned off, since there is a high possibility that this state will continue for a long time, the charging voltage of the power storage device unit 202 is set to 0.0 V. This makes it possible to suppress deterioration of the power storage device unit 202 while the power supply of the imaging device 100 is off.

[0140] Here, for example, when the operation mode is switched from the video mode to the global shutter mode, the charging voltage is changed from 2.0V to 5.0V. If the charging current is small at this time, it takes a long time from when the user switches the mode until shooting becomes possible. Therefore, in the live view state from when the operation mode is switched to when shooting starts, the power storage device charging / discharging unit 204 is in the high output mode, and the power storage device unit 202 is charged with a charging current of 300mA. If shooting starts while still in the high output mode, the power taken out from the battery 108 or the USB power supply unit 110 increases due to the charging current of the power storage device unit 202. Therefore, before shooting starts, the power storage device charging / discharging unit 204 is in the low output mode, and the power storage device unit 202 is charged with a charging current of 100mA. It is sufficient that the high output mode is switched to the low output mode before shooting starts. For example, the low output mode may be switched to when charging is completed using a means such as voltage monitoring. In another example, after the operation mode and the charging voltage of the power storage device unit 202 are changed, the mode may be switched to the low output mode after a predetermined time corresponding to the difference in the charging voltage of the power storage device unit 202 has elapsed.

[0141] 9 is a timing chart showing a typical operation of the image capture device 100 in this embodiment. Note that this timing chart is an example of the operation, and the image capture device 100 operates appropriately in response to a user's operation.

[0142] 9, from the top, 7A shows a user operation on the imaging device 100, and 7B shows the operation of the imaging device 100 associated with the user operation of 7A. 7C shows the amount of current when the imaging sensor 102 operates. 7D shows the temperature change of the power storage device section 202 calculated from the detection value of the temperature sensor 105.

[0143] 7E indicates whether the main power supply path switching unit 401 is to give priority to power supply from the imaging main power supply unit 201 or the power storage device unit 202. When the level of 7E is Low (pass-through), power is preferentially supplied from the imaging main power supply unit 201 to the imaging sensor 102. When the level of 7E is High (resistance ON), power is preferentially supplied from the power storage device unit 202 to the imaging sensor 102.

[0144] 7F indicates the amount of current supplied from the imaging main power supply unit 201. This amount of current must not exceed the maximum power of the battery 108 or the USB power supply unit 110. 7G indicates the amount of current supplied from the power storage device unit 202. 7H indicates the voltage charged to the power storage device unit 202. 7I indicates the maximum amount of current when charging the power storage device unit 202. The operation of the imaging device 100 will be described below in accordance with the user's operations.

[0145] The user turns on the power lever to start the imaging device 100 (T701). It is assumed that the imaging device 100 is initially set to operate in global shutter mode. The imaging device 100 starts an initialization operation (7B), and the current value of the imaging sensor 102 increases (7C). When the current value of the imaging sensor 102 becomes stable, the main power path switching unit 401 is switched (7F). The imaging sensor 102 is operated using power from the power storage device unit 202, and a deterioration determination of the power storage device unit 202 is performed. In this embodiment, it is assumed that the power storage device unit 202 is not deteriorated. When the deterioration determination is completed, the device transitions to a live view state. In the live view state, the charging voltage of the power storage device unit 202 is set to a voltage (about 4.5V) that is unlikely to deteriorate when the temperature is not high and does not take much time to charge (7H). In this embodiment, it is assumed that the device is set to a still image, global shutter mode by a user operation.

[0146] Next, the user presses SW1 to perform an AF operation (T702). At this time, the imaging apparatus 100 enters a shooting standby state, and the power storage device unit 202 is charged up to a voltage (about 5.0 V) that can supply sufficient power to the imaging sensor 102 (7 H).

[0147] After that, the user presses SW2 to start the image capture operation (T703). Because image capture is performed in global shutter mode, the current consumption of the image capture sensor 102 momentarily increases (7C). At this time, the maximum charging current of the power storage device unit 202 is reduced (7I). Specifically, the maximum charging current is reduced from 300 mA to approximately 100 mA. Furthermore, the main power supply path switching unit 401 is switched (7E). Specifically, from the pass-through state, path B is turned ON to change to a path via resistor 402b (approximately 200 mΩ). By performing the above operations, it becomes possible to supply a momentary large current to the image capture sensor 102 from the power storage device unit 202. In addition, the current from the image capture main power supply unit 201 does not increase, and operation can be performed while observing the rated current of the battery 108 and the USB power supply unit 110.

[0148] When the user releases SW1 and SW2, the shooting operation ends and the state returns to the live view state (T704). At this point, the maximum charging current of the power storage device unit 202 is increased (7I). Specifically, it is increased from 100 mA to approximately 300 mA. Furthermore, the main power path switching unit 401 is switched (7E). Specifically, the path via resistor 402b (approximately 200 mΩ) of path B is changed to a pass-through state.

[0149] Next, assume that the user switches modes, changing from still image mode to video mode (T705). In this embodiment, the average current consumption of the image sensor 102 in video mode is high, but does not momentarily exceed that in still image mode (7C). Therefore, there is no problem if the power of the power storage device unit 202 is not used. The charging voltage of the power storage device unit 202 (to about 2.0 V) is lowered (7H), and the maximum charging current to the power storage device unit 202 is also lowered (7I). Specifically, the maximum charging current is reduced from 300 mA to about 100 mA.

[0150] On the other hand, since the average current is large in the moving image mode, the internal temperature of the imaging device 100 rises, and so does the temperature of the built-in power storage device section 202. If moving images are taken for a certain period of time, the temperature exceeds Ta (7D).

[0151] The user's operation ends video capture and transitions to still image mode (T706). The temperature of the power storage device unit 202 exceeds Ta (7D). At this time, in order to prevent deterioration of the power storage device unit 202, the charging voltage of the power storage device unit 202 (about 2.0 V) is not increased (7H).

[0152] Next, suppose that the user presses SW1 and SW2 simultaneously (T707). Here, the power storage device unit 202 charges up to a voltage (about 5.0 V) that can adequately support the power of the image sensor 102 (7H). However, because the temperature of the power storage device unit 202 is high, the charging voltage of the power storage device unit 202 is low, and the time required for charging becomes longer. During this time, the imaging device 100 displays a busy message to notify the user that shooting in global shutter mode is not possible. In other words, the user is indirectly informed that a certain operation cannot be performed due to the rise in temperature of the power storage device unit 202.

[0153] When charging of the power storage device unit 202 is completed, the maximum charging current of the power storage device unit 202 is reduced (7I). Specifically, the maximum charging current is reduced from 300 mA to approximately 100 mA. The main power supply path switching unit 401 is switched (7E). Specifically, from the pass-through state, path B is turned ON to change to a path via resistor 402b (approximately 200 mΩ). By performing the above operations, it becomes possible to supply a momentary large current to the imaging sensor 102 from the power storage device unit 202. Furthermore, the current from the imaging main power supply unit 201 does not become large, and operation can be performed while observing the rated current of the battery 108 and the USB power supply unit 110.

[0154] When the user releases SW1 and SW2, shooting ends and the mode returns to live view mode (T708). The maximum charging current of the power storage device unit 202 is increased (7I). Specifically, it is increased from 100 mA to approximately 300 mA. Furthermore, the main power path switching unit 401 is switched (7E). Specifically, it is changed from the path via resistor 402b (approximately 200 mΩ) of path B to a pass-through state.

[0155] When the temperature of the power storage device unit 202 has dropped sufficiently, operations T709 and T710 are the same as those T703 and T704.

[0156] If there is no user operation for a certain period of time, the imaging device 100 enters a power saving mode (T711). At this time, the power supply to the imaging sensor 102 is turned off, and the voltage of the power storage device unit 202 is reduced (7H).

[0157] Furthermore, when the user turns the power lever of the imaging apparatus 100 to OFF (T712), the voltage of the power storage device section 202 is reduced to 0 V (7H).

[0158] 10 is a diagram for explaining a means for notifying a user in this embodiment. The imaging device 100 notifies a user by displaying a GUI on the display unit 103 in response to an instruction from the control unit 1011. Here, the global shutter mode is an example of an operation mode of the imaging device 100 on the premise that power is supplied from the power storage device unit 202 to the imaging sensor 102.

[0159] A display 1001 is an example of a display to a user when the user sets the global shutter mode and it is determined that shooting operation in the global shutter mode cannot be performed based on the degree of deterioration of the power storage device unit 202. Here, the degree of deterioration of the power storage device unit 202 is calculated from a prediction of the ESR of the power storage device unit 202 and information from the temperature sensor 105.

[0160] Display 1001 notifies the user that the power storage device unit 202 is deteriorating and that image capture is prohibited in the current operation mode. In addition, guidance to an alternative operation mode is provided, and when display 1003 is selected, the operation mode is changed to the alternative operation mode. When display 1002 is selected, the current mode is maintained in a live view state. Display 1001 informs the user that degradation of the power storage device unit 202 is progressing and that image capture is not possible in the current operation mode. Also, image capture can be smoothly performed by another alternative means. Display 1001 is displayed, for example, in step S529 in FIG. 5A.

[0161] Display 1004 is an example of a display to a user when it is determined that shooting operation in the global shutter mode cannot be performed because the temperature of the power storage device unit 202 is extremely low when the user sets the global shutter mode. In display 1004, since it is notified that the power storage device unit 202 cannot be used because it is low temperature, the user can know that shooting can be performed in the global shutter mode if the temperature of the imaging device 100 rises. Also, like display 1001, guidance to another alternative operation mode is also provided, and when display 1006 is selected, the mode is changed to the alternative operation mode. When display 1005 is selected, the current mode is maintained and the live view state is entered. Display 1004 is displayed, for example, in step S529 of FIG. 5A.

[0162] Similar to display 1001, display 1007 is an example of a display to a user when it is determined that shooting operation in the global shutter mode cannot be performed due to the degree of deterioration of the power storage device unit 202 when the user sets the global shutter mode. Display 1007 notifies the user that replacement of the power storage device unit 202 is necessary. For example, if the power storage device unit 202 can be replaced by the user himself, this display can prompt the user to replace the power storage device unit 202. Display 1007 is displayed, for example, in step S529 in FIG. 5A.

[0163] Like the display 1001 and the display 1007, the display 1008 is an example of a display to a user when it is determined that the image capturing operation in the global shutter mode cannot be performed based on the degree of deterioration of the power storage device unit 202 when the user sets the global shutter mode. The display 1008 notifies the user that an abnormality has occurred in the imaging device 100. For example, a user who has confirmed this display can take the imaging device 100 to the manufacturer's service desk to receive repairs. Also, by displaying an error number associated with the deterioration of the power storage device unit 202, the user or the person in charge at the service desk can confirm the error number and know that there is an abnormality in the power storage device unit 202. The display 1008 is displayed, for example, in step S529 in FIG. 5A.

[0164] Display 1009 is an example of a live view display in a state where it has been determined that shooting in global shutter mode is not possible due to the degree of deterioration of the power storage device unit 202. For example, display 1009 is displayed when the user selects display 1002 from display 1001, or when the user selects display 1005 from display 1004. By superimposing an icon indicating that shooting in global shutter mode is prohibited on the live view, the user can easily know whether shooting is currently possible. Furthermore, if this display is being displayed due to low temperature, the icon is erased when the temperature rises and it becomes possible to supply power from the power storage device unit 202 to the image sensor 102. This allows the user to know that shooting is now possible.

[0165] For example, displays 1001, 1004, 1007, 1008, and 1009 are all displayed when it is determined that shooting cannot be performed in the global shutter mode based on the degree of deterioration of the power storage device unit 202. Moreover, these displays are displayed for the first time when the user sets the imaging device 100 to the global shutter mode. As a result, they are not displayed while the user is using the imaging device 100 in another mode, for example, so that the user can concentrate more on shooting even if the power storage device unit 202 has deteriorated.

[0166] Display 1010 is an example of a live view display in a state in which shooting is not possible until charging of the power storage device unit 202 is completed. By superimposing an icon indicating that shooting needs to wait on the live view, the user can easily know whether shooting is currently possible or not. In addition, this icon is erased when charging is completed. This allows the user to know that shooting is now possible. Display 1010 is displayed, for example, in step S518 in FIG. 5B.

[0167] A display 1011 is an example of a setting screen of the imaging device 100. For example, when a user presses a menu button of the imaging device 100, the display unit 103 displays the display 1011. The display 1011 displays an item for checking the deterioration level of the power storage device unit 202, along with an item for checking information on the battery 108, for example. When a user operates the display 1011 to display the deterioration level of the power storage device unit 202, the display 1012 or the display 1013 is displayed according to the deterioration level of the power storage device unit 202. When the deterioration level of the power storage device unit 202 is within a range in which the power storage device unit 202 can be used in the global shutter mode, the display 1012 is displayed. The display 1012 displays the degree of deterioration of the power storage device unit 202. When the deterioration level of the power storage device unit 202 is such that the power storage device unit 202 cannot be used in the global shutter mode, the display 1013 is displayed. The display 1013 notifies the user that replacement is necessary in addition to information on the degree of deterioration of the power storage device unit 202. This display can prompt the user to replace the power storage device unit 202 .

[0168] As described above, according to the above embodiment, the imaging device 100 charges the power storage device unit 202 using power from the imaging main power supply unit 201. In a first operating state, the imaging device 100 controls so that power is supplied from the imaging main power supply unit 201 to the imaging sensor 102 without supplying power from the power storage device unit 202 to the imaging sensor 102. Also, in a second operating state in which the maximum power consumption of the imaging sensor 102 is greater than in the first operating state, the imaging device 100 controls so that power is supplied from the imaging main power supply unit 201 and the power storage device unit 202 to the imaging sensor 102. This makes it possible to reduce the peak current of the main power supply that supplies power to the imaging sensor.

[0169] The disclosure of this specification includes the following imaging apparatus, a control method thereof, a program, and a storage medium.

[0170] (Item 1) 1. An imaging device, comprising: A load circuit; a power supply unit for supplying power to the load circuit; an electricity storage device unit for supplying power to the load circuit; an acquisition means for acquiring a value of an equivalent series resistance of the power storage device unit; a control means for controlling power supply to the load circuit, the control means controlling, in a first operating state of the imaging device, to supply power from the power supply unit to the load circuit without supplying power from the power storage device unit to the load circuit, and controlling, in a second operating state of the imaging device in which a maximum power consumption of the load circuit is higher than in the first operating state, to supply power from the power supply unit and the power storage device unit to the load circuit; Equipped with An imaging device characterized in that the control means changes the limit of the current value of the current supplied from the power supply unit to the load circuit in accordance with the value of the equivalent series resistance of the storage device unit acquired by the acquisition means.

[0171] (Item 2) 2. The imaging device according to item 1, wherein the load circuit is an imaging sensor.

[0172] (Item 3) 3. The imaging device according to item 1 or 2, wherein the power storage device is an electric double layer capacitor or an all-solid-state battery.

[0173] (Item 4) The imaging device described in any one of items 1 to 3, characterized in that the control means has a first supply mode in which a current of a first current value is supplied from the power supply unit to the load circuit, and a second supply mode in which a current of a second current value smaller than the first current value is supplied from the power supply unit to the load circuit.

[0174] (Item 5) 5. The imaging device according to item 4, wherein the control means switches between the first supply mode and the second supply mode by switching impedance between the power supply unit and the load circuit.

[0175] (Item 6) 5. The imaging device according to item 4, wherein the control means switches between the first supply mode and the second supply mode by changing a threshold value of a current value supplied from the power supply unit to the load circuit.

[0176] (Item 7) The imaging device described in any one of items 4 to 6, characterized in that when an equivalent series resistance of the power storage device unit is smaller than a predetermined value, the control means supplies current from the power supply unit to the load circuit in the first supply mode, and when an equivalent series resistance of the power storage device unit is equal to or greater than the predetermined value, the control means supplies current from the power supply unit to the load circuit in the second supply mode.

[0177] (Item 8) 8. The imaging device according to item 7, further comprising a calculation unit for calculating an equivalent series resistance of the power storage device unit.

[0178] (Item 9) The imaging device described in item 8, characterized in that the calculation means calculates the equivalent series resistance of the power storage device unit using the current value of the current flowing through the load circuit, the current value of the current supplied from the power supply unit to the load circuit, and the impedance of the power supply unit.

[0179] (Item 10) The imaging device described in item 8, characterized in that the calculation means calculates the equivalent series resistance of the power storage device unit using the current value of the current flowing in a test circuit connected to the power supply unit and the power storage device unit, the current value of the current supplied from the power supply unit to the test circuit, and the impedance of the power supply unit.

[0180] (Item 11) The imaging device described in item 9 or 10, characterized in that the control means predicts a maximum current of the power supply unit according to the value of the equivalent series resistance of the storage device unit calculated by the calculation means, and limits the current value of the current supplied from the power supply unit to the load circuit when the predicted maximum current exceeds a predetermined value.

[0181] (Item 12) The imaging device described in item 8, characterized in that the control means predicts the voltage to be supplied to the load circuit based on the value of the equivalent series resistance of the storage device section calculated by the calculation means, and limits operation of the imaging device in a specific operating mode if the predicted voltage falls below a predetermined value.

[0182] (Item 13) 13. The imaging device according to item 12, wherein the specific operation mode is a mode for capturing still images.

[0183] (Item 14) 13. The imaging device according to item 12, wherein the specific operation mode is a mode for continuously shooting still images at a speed faster than a predetermined speed.

[0184] (Item 15) 13. The imaging device according to item 12, wherein the specific operating mode is a shooting mode in which signals from multiple pixels of an imaging sensor are read out simultaneously.

[0185] (Item 16) 16. The imaging apparatus according to any one of items 1 to 15, further comprising a charging unit that charges the power storage device unit using power from the power supply unit.

[0186] (Item 17) A method for controlling an imaging apparatus including a load circuit, a power supply unit that supplies power to the load circuit, and a power storage device unit that supplies power to the load circuit, comprising: acquiring a value of an equivalent series resistance of the power storage device unit; a control step of controlling power supply to the load circuit, in a first operating state of the imaging device, controlling power to be supplied from the power supply unit to the load circuit without supplying power from the power storage device unit to the load circuit, and in a second operating state of the imaging device in which a maximum power consumption of the load circuit is higher than in the first operating state, controlling power to be supplied from the power supply unit and the power storage device unit to the load circuit; having A control method for an imaging device, characterized in that in the control process, the limit on the current value of the current supplied from the power supply unit to the load circuit is changed depending on the value of the equivalent series resistance of the storage device unit acquired in the acquisition process.

[0187] (Item 18) Item 18. A program for causing a computer to execute each step of the control method described in Item 17.

[0188] (Item 19) A computer-readable storage medium storing a program for causing a computer to execute each step of the control method described in item 17.

[0189] (Other embodiments) The present invention can also be realized by a process in which a program for realizing one or more functions of the above-mentioned embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) for realizing one or more functions.

[0190] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0191] 100: imaging device, 102: imaging sensor, 103: display unit, 104: recording unit, 105: temperature sensor, 106: power supply control unit, 107: power supply unit, 108: battery, 109: battery monitoring unit, 110: USB power supply unit, 1011: control unit, 1012: imaging drive control unit, 1013: image compression unit, 1014: temporary memory, 1015: image correction unit, 101: CPU, 1016: display image conversion unit, 1071: CPU power supply unit, 1072: imaging power supply unit

Claims

1. 1. An imaging device, comprising: A load circuit; a power supply unit for supplying power to the load circuit; an electricity storage device unit for supplying power to the load circuit; an acquisition means for acquiring a value of an equivalent series resistance of the power storage device unit; a control means for controlling power supply to the load circuit, the control means controlling, in a first operating state of the imaging device, to supply power from the power supply unit to the load circuit without supplying power from the power storage device unit to the load circuit, and controlling, in a second operating state of the imaging device in which a maximum power consumption of the load circuit is higher than in the first operating state, to supply power from the power supply unit and the power storage device unit to the load circuit; Equipped with An imaging device characterized in that the control means changes the limit of the current value of the current supplied from the power supply unit to the load circuit in accordance with the value of the equivalent series resistance of the storage device unit acquired by the acquisition means.

2. 2. The imaging device according to claim 1, wherein the load circuit is an imaging sensor.

3. 2. The imaging apparatus according to claim 1, wherein the power storage device is an electric double layer capacitor or an all-solid-state battery.

4. 2. The imaging device according to claim 1, wherein the control means has a first supply mode in which a current of a first current value is supplied from the power supply unit to the load circuit, and a second supply mode in which a current of a second current value smaller than the first current value is supplied from the power supply unit to the load circuit.

5. 5. The imaging apparatus according to claim 4, wherein the control means switches between the first supply mode and the second supply mode by switching an impedance between the power supply unit and the load circuit.

6. 5. The imaging device according to claim 4, wherein the control means switches between the first supply mode and the second supply mode by changing a threshold value of a current value supplied from the power supply unit to the load circuit.

7. The imaging device according to claim 4, characterized in that the control means supplies current from the power supply unit to the load circuit in the first supply mode when an equivalent series resistance of the power storage device unit is smaller than a predetermined value, and supplies current from the power supply unit to the load circuit in the second supply mode when an equivalent series resistance of the power storage device unit is equal to or greater than the predetermined value.

8. The imaging apparatus according to claim 7 , further comprising a calculation unit that calculates a value of an equivalent series resistance of the power storage device portion.

9. The imaging device according to claim 8, characterized in that the calculation means calculates the equivalent series resistance of the power storage device unit using a current value of a current flowing through the load circuit, a current value of a current supplied from the power supply unit to the load circuit, and an impedance of the power supply unit.

10. The imaging device according to claim 8, characterized in that the calculation means calculates the equivalent series resistance of the power storage device unit using a current value of a current flowing in a test circuit connected to the power supply unit and the power storage device unit, a current value of a current supplied from the power supply unit to the test circuit, and an impedance of the power supply unit.

11. The imaging device according to claim 9, characterized in that the control means predicts a maximum current of the power supply unit in accordance with the value of the equivalent series resistance of the power storage device unit calculated by the calculation means, and limits a current value of the current supplied from the power supply unit to the load circuit when the predicted maximum current exceeds a predetermined value.

12. The imaging device according to claim 8, characterized in that the control means predicts the voltage to be supplied to the load circuit in accordance with the value of the equivalent series resistance of the power storage device calculated by the calculation means, and limits operation of the imaging device in a specific operating mode if the predicted voltage falls below a predetermined value.

13. 13. The imaging apparatus according to claim 12, wherein the specific operation mode is a mode for capturing still images.

14. 13. The image pickup apparatus according to claim 12, wherein the specific operation mode is a mode for continuously shooting still images at a speed faster than a predetermined speed.

15. 13. The image pickup apparatus according to claim 12, wherein the specific operation mode is a shooting mode in which signals from a plurality of pixels of an image sensor are simultaneously read out.

16. 2. The imaging apparatus according to claim 1, further comprising a charging unit that charges the power storage device unit with electric power from the power supply unit.

17. A method for controlling an imaging apparatus including a load circuit, a power supply unit that supplies power to the load circuit, and a power storage device unit that supplies power to the load circuit, comprising: acquiring a value of an equivalent series resistance of the power storage device unit; a control step of controlling power supply to the load circuit, in a first operating state of the imaging device, controlling power to be supplied from the power supply unit to the load circuit without supplying power from the power storage device unit to the load circuit, and in a second operating state of the imaging device in which a maximum power consumption of the load circuit is higher than in the first operating state, controlling power to be supplied from the power supply unit and the power storage device unit to the load circuit; having A control method for an imaging device, characterized in that in the control process, the limit on the current value of the current supplied from the power supply unit to the load circuit is changed depending on the value of the equivalent series resistance of the storage device unit acquired in the acquisition process.

18. A program for causing a computer to execute each step of the control method according to claim 17.

19. A computer-readable storage medium storing a program for causing a computer to execute each step of the control method according to claim 17.

Images