Imaging device

Abstract

An imaging device (100) comprises: a load unit (100A); a first terminal (301) to which first power is input; a second terminal (302) to which second power is input; a third terminal (190) to which third power is input; a power supply line (360) that supplies load power to the load unit (100A); a first power supply switching unit (330) that selects either the first terminal (301) or the second terminal (302) and electrically connects the selected terminal to the power supply line (360); a second power supply switching unit (350) that selects either the third terminal (190) or the second terminal (302) and electrically connects the selected terminal to the power supply line (360), and a control unit (310 and 320) that selects either electrical connection between the second terminal (302) and the power supply line (360) via the first power supply switching unit (330) or electrical connection between the second terminal (302) and the power supply line (360) via the second power supply switching unit (350).

Description

Imaging device

[0001] This disclosure relates to an imaging device.

[0002] Patent Document 1 discloses a digital camera. A battery grip is attached to the digital camera of Patent Document 1. When the battery grip is attached to the digital camera of Patent Document 1, it operates with power supplied from the battery in the battery grip. Also, the digital camera of Patent Document 1 has a USB connector. A mobile battery is connected to the USB connector. The power supplied from the mobile battery is input from the digital camera to the control unit in the battery grip during the imaging operation of the digital camera, and then charges the battery in the digital camera.

[0003] Japanese Unexamined Patent Application Publication No. 2021-64999

[0004] However, when the battery grip is attached to the digital camera of Patent Document 1, it operates with power supplied from the battery in the battery grip. Therefore, even when the load of the digital camera increases when the battery grip is attached, the power supply from the battery in the digital camera cannot be used. Thus, the digital camera of Patent Document 1 cannot operate stably.

[0005] An object of the present disclosure is to provide an imaging device that operates stably.

[0006] An imaging device according to one aspect of the present disclosure captures an image of a subject. The imaging device comprises a load unit, a first terminal, a second terminal, a third terminal, a power supply line, a first power supply switching unit, a second power supply switching unit, and a control unit. The load unit operates the imaging device. A first power supply device that outputs first power is connected to the first terminal. A second power supply device that outputs second power is detachably connected to the second terminal. A third power supply device that outputs third power is detachably connected to the third terminal. The power supply line supplies load power to the load unit. The first power supply switching unit selects either the first terminal or the second terminal and electrically connects it to the power supply line. The second power supply switching unit selects either the third terminal or the second terminal and electrically connects it to the power supply line. The control unit controls the first power switching unit and the second power switching unit to select either an electrical connection between the second terminal and the power supply line via the first power switching unit, or an electrical connection between the second terminal and the power supply line via the second power switching unit.

[0007] An imaging device according to another aspect of the present disclosure captures an image of a subject. The imaging device comprises a load unit, a first terminal, a second terminal, a third terminal, a power supply line, and a control unit. The load unit operates the imaging device. A first power supply device that outputs first power is connected to the first terminal. A second power supply device that outputs second power is detachably connected to the second terminal. A third power supply device that outputs third power is detachably connected to the third terminal. The power supply line supplies load power to the load unit. When the first power is input to the first terminal, the second power is input to the second terminal, and the third power is not input to the third terminal, and the second power supplied to the power supply line is greater than the load power, the control unit supplies a portion of the second power to the load unit via the power supply line, and supplies the surplus power of the second power to the first power supply device via the first terminal.

[0008] An imaging device according to yet another aspect of the present disclosure captures an image of a subject. The imaging device comprises a load unit, a first terminal, a second terminal, a third terminal, a power supply line, a first power supply switching unit, a second power supply switching unit, and a control unit. The load unit operates the imaging device. A first power supply device that outputs first power is connected to the first terminal. A second power supply device that outputs second power is detachably connected to the second terminal. A third power supply device that outputs third power is detachably connected to the third terminal. The power supply line supplies load power to the load unit. The first power supply switching unit selects either the first terminal or the second terminal and electrically connects it to the power supply line. The second power supply switching unit selects either the third terminal or the second terminal and electrically connects it to the power supply line. When the first power is input to the first terminal, the second power is input to the second terminal, and the third power is not input to the third terminal, the control unit causes the first power switching unit to select the first terminal and the second power switching unit to select the second terminal.

[0009] An imaging device according to yet another aspect of the present disclosure captures an image of a subject. The imaging device comprises a load unit, a first terminal, a second terminal, a power supply line, a current control circuit, and a control unit. The load unit operates the imaging device. A first battery is connected to the first terminal. A second battery is connected to the second terminal. The power supply line supplies load power to the load unit. The current control circuit controls the current supplied from the second battery to the power supply line. The control unit controls the current control circuit to control the current supplied from the second battery to the power supply line such that the ratio of the first power supplied from the first battery to the second power supplied from the second battery matches the ratio of the remaining capacity of the first battery to the remaining capacity of the second battery.

[0010] The imaging device described herein can be operated stably.

[0011] This is a block diagram showing the configuration of a digital camera according to Embodiment 1 of the present disclosure. This is a diagram showing the configuration of a power control unit included in the digital camera according to Embodiment 1 of the present disclosure. This is a diagram showing another example of a battery grip attached to the digital camera according to Embodiment 1 of the present disclosure. This is a diagram showing the configuration of a first power switching unit, a second power switching unit, and a second power control unit included in the digital camera according to Embodiment 1 of the present disclosure. This is a diagram showing a first power condition table that associates the first connection relationship between each of the first terminal, second terminal, and USB terminal and a power device with power conditions 1 to 9. This is a diagram showing a second power condition table that associates the second connection relationship between each of the first terminal, second terminal, and USB terminal and a power device with power conditions 11 to 19. This is a diagram showing a third power condition table that associates the third connection relationship between each of the first terminal, second terminal, and USB terminal and a power device with power conditions 21 to 29. This is a diagram showing a first power mode table that associates power conditions 1 to 9 with power modes 1 to 9 and power modes A to F. This figure shows a second power mode table that associates power conditions 11 to 19 with power modes 11 to 19 and power modes A to F. This figure shows a third power mode table that associates power conditions 21 to 29 with power modes 21 to 29 and power modes A to F. This figure shows a fourth power mode table that associates power modes 1 to 5, 6-1, 6-2, 7, 8-1, 8-2, 9, 11 to 19 and 21 to 29 with power modes A to F. This figure shows a power switching table that associates power modes A to F with the states of the first FET, second FET, third FET, fourth FET, fifth FET, sixth FET, seventh FET and eighth FET and the states of the state transition circuit. This figure shows some other examples of power switching tables that associate power modes A to F with the states of the first FET, second FET, third FET, fourth FET, fifth FET, sixth FET, seventh FET and eighth FET and the states of the state transition circuit. This diagram shows the power mode transitions of a digital camera according to Embodiment 1 of this disclosure. This diagram shows the power mode transitions of a digital camera according to Embodiment 1 of this disclosure. This diagram shows the power mode transitions of a digital camera according to Embodiment 1 of this disclosure.This diagram shows the transition of power modes when an internal coupler is connected to a first terminal included in a digital camera according to Embodiment 1 of this disclosure. This diagram shows the configuration of a power control unit included in a digital camera according to Embodiment 2 of this disclosure. This diagram shows the configuration of a first power switching unit, a second power switching unit, and a second power control unit included in a digital camera according to Embodiment 2 of this disclosure. This diagram shows a part of the power switching table stored in the memory of the first power control unit included in a digital camera according to Embodiment 2 of this disclosure. This flowchart shows the standalone power supply control performed by the first power control unit included in a digital camera according to Embodiment 2 of this disclosure. This flowchart shows the capacity balancing power supply control performed by the first power control unit included in a digital camera according to Embodiment 2 of this disclosure. This diagram shows the time change of the battery voltage of the internal battery. This diagram shows the second value of the first undercut voltage.

[0012] Embodiments of the imaging apparatus of this disclosure will be described below with reference to the drawings. However, this disclosure is not limited to the embodiments described below, and can be implemented in various forms without departing from its essence. In addition, explanations may be omitted where necessary to avoid repetition. Furthermore, in the drawings, the same or corresponding parts are denoted by the same reference numerals and their descriptions are not repeated.

[0013] [Embodiment 1] The configuration and operation of a lens-interchangeable digital camera as an example of an imaging device according to Embodiment 1 of the present disclosure will be described below.

[0014] 1. Configuration The configuration of the digital camera will be explained below using diagrams.

[0015] 1-1. Diagram 1 of the digital camera configuration is a block diagram showing the configuration of the digital camera 100 of Embodiment 1. The digital camera 100 consists of a camera body 102 and an interchangeable lens 101 that can be attached to the camera body 102. The interchangeable lens 101 is an electric zoom lens. Specifically, the interchangeable lens 101 is equipped with a lens mount 130, and the camera body 102 is equipped with a body mount 140, and the lens mount 130 and the body mount 140 are mechanically and electrically connected. The camera body 102 and the interchangeable lens 101 send and receive data and signals to each other via the lens mount 130 and the body mount 140. Power is also supplied from the camera body 102 to the interchangeable lens 101 via the lens mount 130 and the body mount 140.

[0016] The camera body 102 can be detachably fitted with a battery 210A. A battery grip 103 is detachably fitted to the camera body 102. The battery grip 103 shown in Figure 1 can be fitted with a battery 220A. Hereafter, battery 210A may be referred to as "internal battery 210A". Also, battery 220A may be referred to as "external battery 220A". Battery 210A is an example of a "first power supply device". External battery 220A is an example of a "second power supply device".

[0017] 1-2. Camera Body Configuration In addition to the body mount 140 described above, the camera body 102 further comprises a CMOS image sensor 150, a timing generator 151 (TG), a power switch 152, a camera controller 153, a DRAM (Dynamic Random Access Memory) 155, a flash memory 156, a release button 160, an LCD monitor 163, a card slot 165, an operation unit 170, an image processing unit 172, a mechanical shutter 180, a USB terminal 190, a power control unit 300, a first terminal 301, and a second terminal 302.

[0018] The camera controller 153 controls the operation of the entire digital camera 100 by controlling various parts of the digital camera 100, such as the CMOS image sensor 150. When controlling the various parts of the digital camera 100, the camera controller 153 uses the DRAM 155 as work memory. The camera controller 153 may be configured as a hardwired electronic circuit or as a microcomputer that executes a program. Furthermore, the camera controller 153 may be configured as a single semiconductor chip together with the image processing unit 172 and the DRAM 155, or as separate semiconductor chips.

[0019] The CMOS image sensor 150 converts the light focused by the interchangeable lens 101 into a digital signal and outputs it to the image processing unit 172. The digital signal represents image data.

[0020] The CMOS image sensor 150 operates at timings controlled by the timing generator 151. The operations of the CMOS image sensor 150 controlled by the timing generator 151 include still image acquisition, through-image acquisition, data transfer, and electronic shutter operation. Through-images are primarily moving images. Note that other image sensors, such as NMOS image sensors or CCD image sensors, may be used instead of the CMOS image sensor 150.

[0021] The image processing unit 172 performs predetermined image processing on the image data output from the CMOS image sensor 150. These predetermined image processing steps include, for example, gamma correction, white balance correction, scratch correction, YC conversion, digital zoom, compression, and decompression. However, the predetermined image processing steps are not limited to these.

[0022] The liquid crystal monitor 163 is a display unit located on the back of the camera body 102. The liquid crystal monitor 163 displays a screen that notifies the user of information such as the settings of the digital camera 100. Furthermore, the liquid crystal monitor 163 displays the through image processed by the image processing unit 172. In Embodiment 1, the liquid crystal monitor 163 is exemplified as the display unit of the camera body 102, but the display unit is not limited to the liquid crystal monitor 163. For example, the camera body 102 may be equipped with an organic EL display as its display unit.

[0023] The flash memory 156 functions as an internal memory for storing image data processed by the image processing unit 172. The flash memory 156 also stores computer programs and parameters used by the camera controller 153 when performing various control operations. The camera controller 153 may read image data from the flash memory 156 and display it on the liquid crystal monitor 163.

[0024] A memory card MC is detachably mounted in the card slot 165. The memory card MC is electrically and mechanically connected to the card slot 165. The card slot 165 may also have a function to control the memory card MC.

[0025] The memory card MC is an external memory equipped with memory elements such as flash memory. The camera controller 153 may store the image data processed by the image processing unit 172 in the memory card MC. Alternatively, the camera controller 153 may read the image data from the memory card MC and display it on the liquid crystal monitor 163. In Embodiment 1, the memory card MC is used as an example of external memory, but the external memory is not limited to the memory card MC. For example, a recording medium such as an optical disc may be used as external memory.

[0026] The shutter release button 160 can be operated in two stages: half-press and full-press. The camera controller 153 causes the interchangeable lens 101 to perform autofocus operation in response to the user's half-press operation of the shutter release button 160. The camera controller 153 also causes the CMOS image sensor 150 to perform still image capture operation in response to the user's full-press operation of the shutter release button 160. The camera controller 153 then records the image data of the still image generated according to the timing of the full-press operation of the shutter release button 160 to the flash memory 156 or memory card MC.

[0027] The mechanical shutter 180 adjusts the exposure time of the light incident on the CMOS image sensor 150. The mechanical shutter 180 is driven by an actuator (not shown), such as a DC motor or a stepping motor, and the camera controller 153 controls the actuator to control the operation of the mechanical shutter 180. For example, the camera controller 153 controls the speed at which the mechanical shutter 180 is driven.

[0028] The control unit 170 receives user input and outputs an operation signal corresponding to that input to the camera controller 153. For example, the control unit 170 includes a cross button. When an interchangeable lens 101 with an electric zoom function is attached to the camera body 102, the camera controller 153 assigns the function of zoom operation buttons to the left and right buttons included in the cross button. If the interchangeable lens 101 with an electric zoom function attached to the camera body 102 has a zoom lever for the user to perform zoom operation, the camera controller 153 may or may not assign the function of zoom operation buttons to the control unit 170.

[0029] External USB devices (not shown) can be detachably connected to the USB terminal 190 via a USB cable (not shown). USB devices include USB power devices such as USB mobile batteries MB and USB chargers, and USB load devices such as SSDs (Solid State Drives). Therefore, USB power devices and USB load devices can be selectively connected to the USB terminal 190.

[0030] The USB power device is a USB device that supplies power to the digital camera 100. The USB load device is a USB device that operates by receiving power from the digital camera 100. When the USB load device is connected to the USB terminal 190, power is supplied from the USB terminal 190 to the USB load device. In addition to an SSD, the USB load device includes a smartphone, etc. The USB terminal 190 is an example of a "third terminal," and the USB power device is an example of a "third power device." The USB load device is also an example of a "load device." If an SSD is connected to the USB terminal 190, the camera controller 153 may record image data to the SSD, or it may read image data from the SSD and display it on the LCD monitor 163.

[0031] A first power supply device is detachably connected to the first terminal 301. The first power supply device outputs first power to the first terminal 301. In the example shown in Figure 1, an internal battery 210A (an example of the first power supply device) is connected to the first terminal 301. The internal battery 210A may be, for example, a dry cell battery or a rechargeable battery. A second power supply device is detachably connected to the second terminal 302. The second power supply device outputs second power to the second terminal 302. In the example shown in Figure 1, an external battery 220A (an example of the second power supply device) attached to the battery grip 103 is connected to the second terminal 302. The external battery 220A may be, for example, a dry cell battery or a rechargeable battery. If a USB power supply device is connected to the USB terminal 190, the USB power supply device outputs third power to the USB terminal 190.

[0032] The power switch 152 accepts power on and power off operations from the user. When the power switch 152 accepts a power on operation, the camera controller 153 controls the power control unit 300 to start supplying power to each part of the camera body 102 and interchangeable lens 101 (camera system load unit 100A, which will be described later with reference to Figure 2). When the power switch 152 accepts a power off operation, the camera controller 153 controls the power control unit 300 to stop supplying power to each part of the camera body 102 and interchangeable lens 101.

[0033] The power control unit 300 controls, for example, the power source for supplying power to each part of the digital camera 100. For example, when the internal battery 210A and the external battery 220A are connected to the first terminal 301 and the second terminal 302, respectively, and a mode with relatively low power consumption, such as still image shooting mode, is selected as the operating mode of the digital camera 100, the power control unit 300 supplies load power to each part of the digital camera 100 based on the second power input from the external battery 220A to the second terminal 302. Furthermore, if the load power is less than the second power and surplus power is generated in the second power, the power control unit 300 supplies that surplus power to the internal battery 210A via the first terminal 301 to charge the internal battery 210A.

[0034] 1-3. Configuration of the interchangeable lens In addition to the lens mount 130 described above, the interchangeable lens 101 further comprises a focus lens 110, a focus lens drive unit 111, a zoom lens 112, a zoom lens drive unit 113, a zoom lens position detection unit 114, a focus ring 115, a zoom ring 116, a lens controller 120, a DRAM 121, and a flash memory 122. The interchangeable lens 101 may further include an image stabilization lens in addition to the lens shown in Figure 1.

[0035] The lens controller 120 controls the operation of the entire interchangeable lens 101. The lens controller 120 may be composed of hardwired electronic circuits or a microcomputer that executes a computer program.

[0036] The lens controller 120 uses the DRAM 121 as work memory when controlling various parts of the interchangeable lens 101. The flash memory 122 stores computer programs and parameters used by the lens controller 120 when performing various control operations. The flash memory 122 also stores lens data, including characteristic values ​​of the interchangeable lens 101 such as the lens name, lens ID, serial number, F-number, and focal length. The lens controller 120 notifies the camera controller 153 of the lens data, and the camera controller 153 performs various controls according to the lens data.

[0037] The zoom lens 112 has a lens configuration for changing the magnification of the subject image formed on the CMOS image sensor 150 by the optical system of the interchangeable lens 101. The zoom lens drive unit 113 is a mechanical mechanism that moves the zoom lens 112 along the optical axis of the optical system based on the user's operation of the zoom ring 116. The position of the zoom lens 112 is detected at any time by the zoom lens position detection unit 114 and notified to the lens controller 120.

[0038] The focus lens 110 has a lens configuration for changing the focus state of the subject image formed on the CMOS image sensor 150 by the optical system of the interchangeable lens 101. When the focus ring 115 is operated by the user, information regarding the amount of operation of the focus ring 115 is notified to the lens controller 120. Based on the notified information regarding the amount of operation of the focus ring 115, the lens controller 120 controls the focus lens drive unit 111 to drive the focus lens 110.

[0039] The focus lens drive unit 111 is controlled by the lens controller 120 to drive the focus lens 110 to move forward and backward along the optical axis of the optical system. The focus lens drive unit 111 may have actuators such as a stepping motor, a DC motor, or an ultrasonic motor.

[0040] Incidentally, the image data output from the CMOS image sensor 150 to the image processing unit 172 indicates the subject image formed on the CMOS image sensor 150. The camera body 102 (digital camera 100) captures the subject image formed on the CMOS image sensor 150.

[0041] 1-4. Configuration of Power Control Unit Next, the configuration of the power control unit 300 will be described with reference to FIG. 2. FIG. 2 is a diagram showing the configuration of the power control unit 300 included in the digital camera 100 of Embodiment 1. As shown in FIG. 2, the power control unit 300 includes a first power control unit 310, a second power control unit 320, a PD controller 340, a first power line 360, a second power line 370, a third power line 380, and a fourth power line 390.

[0042] The first power line 360 supplies load power to the camera system load unit 100A. The camera system load unit 100A is a load unit that operates the digital camera 100. The camera system load unit 100A includes each part of the digital camera 100 such as the camera controller 153 and the lens controller 120 described with reference to FIG. 1. The first power line 360 is an example of a "power supply line".

[0043] The magnitude of the load power consumed by the camera system load unit 100A varies depending on the operation mode of the digital camera 100. The operation modes of the digital camera 100 include, for example, a still image shooting mode and a moving image shooting mode. The load power consumed by the camera system load unit 100A during the moving image shooting mode is greater than that during the still image shooting mode. Also, the magnitude of the load power consumed by the camera system load unit 100A increases when a USB load device such as an SSD is connected to the USB terminal 190.

[0044] The second power line 370 controls the electrical connection between each of the first terminal 301 and the second terminal 302 and the first power line 360. For example, the second power line 370 selectively supplies one of the first power input to the first terminal 301 and the second power input to the second terminal 302 to the first power line 360.

[0045] More specifically, the second power line 370 includes a first power switching unit 330. The first terminal 301 and the second terminal 302 are electrically connected to the first power switching unit 330. Therefore, when the internal battery 210A is connected to the first terminal 301, the internal battery 210A is electrically connected to the first power switching unit 330 via the first terminal 301. Similarly, when the external battery 220A is connected to the second terminal 302, the external battery 220A is electrically connected to the first power switching unit 330 via the second terminal 302.

[0046] The first power switching unit 330 is controlled by the first power control unit 310 to select one of the first terminal 301 and the second terminal 302 and electrically connect it to the first power line 360. Specifically, one of the first terminal 301 and the second terminal 302 is electrically connected to the first power line 360 via the second power control unit 320.

[0047] The third power line 380 controls the electrical connection between each of the USB terminal 190 and the second terminal 302 and the first power line 360. For example, the third power line 380 selectively supplies one of the third power input to the USB terminal 190 and the second power input to the second terminal 302 to the first power line 360.

[0048] More specifically, the third power line 380 includes a second power switching unit 350. The USB terminal 190 and the second terminal 302 are electrically connected to the second power switching unit 350. Therefore, when a USB power device such as a USB mobile battery MB is connected to the USB terminal 190, the USB power device is electrically connected to the second power switching unit 350 via the USB terminal 190. Similarly, when the external battery 220A is connected to the second terminal 302, the external battery 220A is electrically connected to the second power switching unit 350 via the second terminal 302. In Embodiment 1, the USB terminal 190 is electrically connected to the second power switching unit 350 via the PD controller 340.

[0049] The second power switching unit 350 is controlled by the second power control unit 320 to select either the USB terminal 190 or the second terminal 302 and electrically connect it to the first power line 360. Specifically, either the USB terminal 190 or the second terminal 302 is electrically connected to the first power line 360 ​​via the second power control unit 320.

[0050] Next, let's explain the USB terminal 190. The USB terminal 190 includes the VBUS terminal 191. The VBUS terminal 191 performs power input and output with the USB device connected to the USB terminal 190. Specifically, when a USB power device is connected to the USB terminal 190, power is input from the USB power device to the VBUS terminal 191. Also, when a USB load device is connected to the USB terminal 190, power is output from the VBUS terminal 191 to the USB load device.

[0051] In Embodiment 1, the USB terminal 190 is a Type-C connector and includes a CC (Configuration Channel) terminal 192.

[0052] The PD controller 340 determines, via the CC terminal 192, whether the USB device connected to the USB terminal 190 is a USB power device or a USB load device, and notifies the first power control unit 310 of the determination result.

[0053] Furthermore, the PD controller 340 determines whether the USB device connected to the USB terminal 190 is a USB device compliant with the USB_PD standard, and notifies the first power control unit 310 of the determination result. Hereinafter, compliance with the USB_PD standard will be referred to as "PD compatible," and non-compliance with the USB_PD standard will be referred to as "PD non-compatible." Also, a PD compatible USB device will be referred to as a "PD compatible device," and a non-PD compatible USB device will be referred to as a "PD non-compatible device." When a PD compatible device is connected to the USB terminal 190, the PD controller 340 negotiates with the PD compatible device via the CC terminal 192.

[0054] When a non-PD compatible USB power supply device is connected to the USB terminal 190, the PD controller 340 detects the voltage and current values ​​of the power input from the non-PD compatible USB power supply device to the VBUS terminal 191 via the CC terminal 192, and notifies the first power supply control unit 310 of the detection results.

[0055] When a PD-compatible USB power supply device is connected to the USB terminal 190, the PD controller 340 negotiates with the PD-compatible USB power supply device and causes the PD-compatible USB power supply device to input a predetermined amount of power to the VBUS terminal 191. The voltage and current values ​​of the predetermined power are greater than the voltage and current values ​​of the power input to the VBUS terminal 191 from a USB power supply device of a non-PD-compatible device.

[0056] When a PD-compatible USB load device is connected to the USB terminal 190, the PD controller 340 negotiates with the USB load device and notifies the first power control unit 310 of the voltage and current values ​​of the power to be supplied from the VBUS terminal 191 to the PD-compatible USB load device.

[0057] Next, the fourth power line 390 will be explained. When a USB load device is connected to the USB terminal 190, the fourth power line 390 supplies power from the camera system load unit 100A to the VBUS terminal 191. More specifically, the fourth power line 390 supplies power to the VBUS terminal 191 via the PD controller 340. The USB load device is a load added to the digital camera 100, and when a USB load device is connected to the USB terminal 190, the load power supplied from the first power line 360 ​​to the camera system load unit 100A increases.

[0058] More specifically, the fourth power line 390 includes a step-down DC / DC converter 391. The step-down DC / DC converter 391 steps down the voltage of the power supplied from the camera system load section 100A to the VBUS terminal 191.

[0059] Next, the first power control unit 310 and the second power control unit 320 will be described. The first power control unit 310 may be composed of hardwired electronic circuits or of a microcomputer that executes programs. In Embodiment 1, the first power control unit 310 has a memory (not shown). The memory is, for example, a semiconductor memory.

[0060] The first power control unit 310 controls the first power switching unit 330 based on the current operating mode of the digital camera 100 and the current power information. The current operating mode of the digital camera 100 is notified to the first power control unit 310 from the camera controller 153.

[0061] The power information includes information indicating whether a first power device is connected to the first terminal 301, information on the type of the first power device, temperature information of the first power device, and information on the voltage value of the power input from the first power device to the first terminal 301. The power information also includes information indicating whether a second power device is connected to the second terminal 302, information on the type of the second power device, temperature information of the second power device, and information on the voltage value of the power input from the second power device to the second terminal 302. Furthermore, the power information includes information indicating whether a USB device is connected to the USB terminal 190, information on the type of USB device, information on the voltage value of the power input from the USB device (USB power device) to the USB terminal 190, and information on the voltage value of the power supplied from the USB terminal 190 to the USB device (PD-compatible USB load device).

[0062] In Embodiment 1, the first power control unit 310 identifies the current power condition that matches the current operating mode and current power information of the digital camera 100 from among a plurality of power conditions (power condition 1 to power condition 9, power condition 11 to power condition 19, and power condition 21 to power condition 29) registered in the first power condition table TA1 to the third power condition table TA3, which will be described later with reference to Figures 5 to 7. Then, the first power control unit 310 identifies the power mode that matches the current power condition from among a plurality of power modes (power mode A to power mode F) registered in the first power mode table TA4 to the third power mode table TA6, which will be described later with reference to Figures 8 to 10, and controls the first power switching unit 330 based on the identified power mode and the power switching table TA8, which will be described later with reference to Figure 12.

[0063] Furthermore, the first power condition tables TA1 to TA3, which will be described later with reference to Figures 5 to 7, the first power mode tables TA4 to TA6, which will be described later with reference to Figures 8 to 10, or the fourth power mode table TA7, which will be described later with reference to Figure 11, and the power switching table TA8, which will be described later with reference to Figure 12, or the power switching table TA8, which will be described later with reference to Figure 13, are stored in the memory of the first power control unit 310.

[0064] The second power control unit 320 may be composed of hardwired electronic circuits or a microcomputer that executes programs. In Embodiment 1, the second power control unit 320 has a memory (not shown). The memory is, for example, a semiconductor memory. The memory in the second power control unit 320 stores a power switching table TA8, which will be described later with reference to Figure 12 or Figure 13.

[0065] In Embodiment 1, the second power control unit 320 communicates with the first power control unit 310 and obtains a power mode that matches the current power conditions from the first power control unit 310. Then, the second power control unit 320 controls the second power switching unit 350 based on the power mode obtained from the first power control unit 310 and the power switching table TA8, which will be described later with reference to Figure 12.

[0066] The first power control unit 310 and the second power control unit 320 cooperate to control the first power switching unit 330 and the second power switching unit 350 to select either an electrical connection between the second terminal 302 and the first power line 360 ​​via the first power switching unit 330, or an electrical connection between the second terminal 302 and the first power line 360 ​​via the second power switching unit 350. In Embodiment 1, the first power control unit 310 and the second power control unit 320 constitute the "control unit" included in the imaging device of this disclosure.

[0067] Next, the second power control unit 320 will be described further. As shown in Figure 2, the second power control unit 320 includes a state transition circuit 321. The second power line 370 is electrically connected to the first power line 360 ​​via the state transition circuit 321. The state transition circuit 321 can transition between a first state and a second state. The controller 323 of the second power control unit 320, which will be described later with reference to Figure 4, controls the state of the state transition circuit 321. The first state indicates a state in which the terminal selected by the first power switching unit 330 is electrically connected to the first power line 360. The second state indicates a state in which one of the power input from the terminal selected by the first power switching unit 330 and the power input from the terminal selected by the second power switching unit 350 is selected and supplied to the first power line 360.

[0068] 1-5. Other Examples of Battery Grips Next, with reference to Figure 3, other examples of the battery grip 103 will be described. Figure 3 is a diagram showing another example of the battery grip 103 attached to the digital camera 100 of Embodiment 1. As shown in Figure 3, the battery grip 103 may also be an external coupler 220B. The external coupler 220B is another example of the "second power supply device".

[0069] The external coupler 220B is detachably attached to the digital camera 100. The external coupler 220B has a USB terminal 230 and a PD controller 240. A PD-compatible USB power device, such as a PD-compatible USB mobile battery MB or a PD-compatible USB charger, can be detachably connected to the USB terminal 230 via a USB cable (not shown).

[0070] The USB terminal 230 includes a VBUS terminal 231. Power is input to the VBUS terminal 231 from a USB power supply device. The VBUS terminal 231 is electrically connected to the second terminal 302 via the PD controller 240. Therefore, the power output from the USB power supply device is input to the second terminal 302 via the PD controller 240.

[0071] In Embodiment 1, the USB terminal 230 is a Type-C connector and includes a CC terminal 232. The PD controller 240, like the PD controller 340, negotiates with a PD-compatible USB power supply device connected to the USB terminal 230 via the CC terminal 232, and causes the PD-compatible USB power supply device to input a predetermined power to the VBUS terminal 231. As already explained, the voltage and current values ​​of the predetermined power are greater than the voltage and current values ​​of the power input to the VBUS terminal 231 from a non-PD-compatible USB power supply device.

[0072] 1-6. Other Examples of the First Power Device Although not shown in the diagram, an internal coupler 210B is detachably connected to the first terminal 301 in place of the internal battery 210A, similar to the second terminal 302. The configuration of the internal coupler 210B is substantially the same as that of the external coupler 220B described with reference to Figure 3, so its description is omitted. The internal coupler 210B is another example of the "first power device". Similar to the external coupler 220B, a PD-compatible USB power device is connected to the internal coupler 210B.

[0073] 1-7. Configuration of the First Power Switching Unit, the Second Power Switching Unit, and the Second Power Control Unit Next, the configurations of the first power switching unit 330, the second power switching unit 350, and the second power control unit 320 will be described with reference to Figure 4. Figure 4 is a diagram showing the configurations of the first power switching unit 330, the second power switching unit 350, and the second power control unit 320 included in the digital camera 100 of Embodiment 1.

[0074] As shown in Figure 4, the first power supply switching unit 330 may have an electronic circuit or an electrical circuit. The first power supply switching unit 330 may also be a power supply switching circuit. In Embodiment 1, the first power supply switching unit 330 includes a first FET 331, a second FET 332, a first diode 333, a third FET 334, a fourth FET 335, and a second diode 336. The first FET 331, the second FET 332, the third FET 334, and the fourth FET 335 are, for example, P-channel MOSFETs.

[0075] The first FET 331 and the second FET 332 are connected back-to-back. The source of the first FET 331 is electrically connected to the first terminal 301. The source of the second FET 332 is electrically connected to the first power line 360 ​​via the second power control unit 320. The first diode 333 is connected in parallel with the second FET 332. Figure 4 illustrates an internal battery 210A connected to the first terminal 301.

[0076] Similarly, the third FET 334 and the fourth FET 335 are connected back-to-back. The source of the third FET 334 is electrically connected to the second terminal 302. The source of the fourth FET 335 is electrically connected to the second power line 370 between the source of the second FET 332 and the second power control unit 320. The second diode 336 is connected in parallel with the fourth FET 335. Figure 4 illustrates an external battery 220A connected to the second terminal 302.

[0077] The turn-on and turn-off of the first FET 331, second FET 332, third FET 334, and fourth FET 335 are controlled by the first power supply control unit 310, as described with reference to Figure 2. Specifically, the first power supply control unit 310 generates a gate signal GA11 to drive the gate of the first FET 331, thereby controlling the turn-on and turn-off of the first FET 331. Similarly, the first power supply control unit 310 generates gate signals GA12, GA13, and GA14 to drive the gates of the second FET 332, third FET 334, and fourth FET 335, thereby controlling the turn-on and turn-off of the second FET 332, third FET 334, and fourth FET 335. Note that the initial state of the first FET 331 and third FET 334 is the ON state, and the initial state of the second FET 332 and fourth FET 335 is the OFF state.

[0078] As shown in Figure 4, the second power supply switching unit 350 may have an electronic circuit or an electrical circuit. The second power supply switching unit 350 may also be a power supply switching circuit. In Embodiment 1, the second power supply switching unit 350 has a fifth FET 351, a sixth FET 352, a seventh FET 353, and an eighth FET 354. The fifth FET 351, sixth FET 352, seventh FET 353, and eighth FET 354 are, for example, P-channel MOSFETs.

[0079] The fifth FET 351 and the sixth FET 352 are connected back-to-back. The source of the fifth FET 351 is electrically connected to the second terminal 302. The source of the sixth FET 352 is electrically connected to the third power line 380 between the source of the eighth FET 354 and the second power control unit 320.

[0080] Similarly, the seventh FET 353 and the eighth FET 354 are connected back-to-back. The source of the seventh FET 353 is electrically connected to the VBUS terminal 191. The source of the eighth FET 354 is electrically connected to the first power line 360 ​​via the second power control unit 320. Figure 4 illustrates a PD-compatible USB mobile battery MB connected to the USB terminal 190.

[0081] The turn-on and turn-off of the fifth FET 351, sixth FET 352, seventh FET 353, and eighth FET 354 are controlled by the controller 323 of the second power supply control unit 320. Specifically, the controller 323 generates a gate signal GA21 to drive the gate of the fifth FET 351, thereby controlling the turn-on and turn-off of the fifth FET 351. Similarly, the controller 323 generates gate signals GA22, GA23, and GA24 to drive the gates of the sixth FET 352, seventh FET 353, and eighth FET 354, thereby controlling the turn-on and turn-off of the sixth FET 352, seventh FET 353, and eighth FET 354. Note that the initial state of the fifth FET 351 to eighth FET 354 is the off state.

[0082] As shown in Figure 4, the second power supply control unit 320 includes the state transition circuit 321 described with reference to Figure 2, a step-up / step-down DC / DC converter 322, and a controller 323. The second power supply control unit 320 may be an integrated circuit, for example. The memory in the second power supply control unit 320 described with reference to Figure 2 may be provided in the controller 323, for example.

[0083] The state transition circuit 321 includes an N-channel MOSFET 321a. The source of the second FET 332 included in the first power supply switching unit 330 is electrically connected to the first power supply line 360 ​​via the N-channel MOSFET 321a. The source of the fourth FET 335 included in the first power supply switching unit 330 is also electrically connected to the first power supply line 360 ​​via the N-channel MOSFET 321a. The controller 323 controls the gate of the N-channel MOSFET 321a to transition the state transition circuit 321 between the first state and the second state described above.

[0084] Specifically, when the controller 323 sets the N-channel MOSFET 321a to the first state, it sets the N-channel MOSFET 321a to the fully-on state. As a result, the terminal selected by the first power supply switching unit 330 is electrically connected to the first power supply line 360.

[0085] Furthermore, when the controller 323 sets the state transition circuit 321 to the second state, if the source voltage of the Nch MOSFET 321a is higher than the drain voltage, power input from the terminal selected by the first power supply switching unit 330 is supplied to the first power supply line 360. If the source voltage of the Nch MOSFET 321a is lower than the drain voltage, the controller 323 controls the gate voltage of the Nch MOSFET 321a to prevent current from flowing back from the drain to the source of the Nch MOSFET 321a. As a result, the backflow of current to the terminal selected by the first power supply switching unit 330 is prevented.

[0086] The third power line 380 is electrically connected to the first power line 360 ​​via a step-up / step-down DC / DC converter 322. The step-up / step-down DC / DC converter 322 is controlled by the controller 323 to step up or step down the voltage of the power input from the terminal selected by the second power switching unit 350 and output it to the first power line 360. The controller 323 may control the step-up / step-down DC / DC converter 322 according to the amount of load power consumed by the camera system load unit 100A. For example, when the operating mode of the digital camera 100 is switched to an operating mode with relatively high power consumption, such as video recording mode, the controller 323 may step up the voltage of the power input from the terminal selected by the second power switching unit 350 and output it to the first power line 360.

[0087] 2. Operation 2-1. Details of the process performed by the first power control unit Next, with reference to Figures 5 to 13, the details of the process performed by the first power control unit 310 will be described.

[0088] 2-1-1. Process for Identifying Power Conditions First, the process for identifying power conditions will be explained with reference to Figures 5 to 7. Figure 5 is a diagram showing the first power condition table TA1, which associates the first connection relationships between each of the first terminal 301, the second terminal 302, and the USB terminal 190 and the power device with power conditions 1 to 9. Specifically, the first connection relationship shows the connection relationships between each of the first terminal 301 and the second terminal 302 and the power device when the USB power device is not connected to the USB terminal 190. Specifically, as shown in Figure 5, the first power condition table TA1 includes the main body column FD1, the battery grip column FD2, and the power condition column FD3.

[0089] "None" in the main unit column FD1 indicates that the first power supply device is not connected to the first terminal 301. "Internal battery" in the main unit column FD1 indicates that the internal battery 210A is connected to the first terminal 301. "Internal coupler" in the main unit column FD1 indicates that the internal coupler 210B is connected to the first terminal 301.

[0090] "None" in the Battery Grip column FD2 indicates that the second power supply device is not connected to the second terminal 302. "External Battery" in the Battery Grip column FD2 indicates that the external battery 220A is connected to the second terminal 302. "External Coupler" in the Battery Grip column FD2 indicates that the external coupler 220B is connected to the second terminal 302.

[0091] The power supply conditions field FD3 registers power supply conditions corresponding to the connection relationships between the first terminal 301 and the second terminal 302 and the power supply device. As a result, the connection relationships between the first terminal 301 and the second terminal 302 and the power supply device are associated with power supply conditions 1 to 9. For example, the first power supply conditions table TA1 associates power supply condition 7 with the state in which the internal coupler 210B is connected to the first terminal 301 and the external battery 220A is connected to the second terminal 302.

[0092] Figure 6 shows the second power condition table TA2, which associates the second connection relationships between each of the first terminal 301, the second terminal 302, and the USB terminal 190 and the power device, with power conditions 11 to 19. Specifically, the second connection relationship shows the connection relationships between each of the first terminal 301 and the second terminal 302 and the power device when a PD-compatible USB power device is connected to the USB terminal 190. Specifically, the second power condition table TA2 includes a main body column FD1, a battery grip column FD2, and a power condition column FD3, similar to the first power condition table TA1. Note that the configuration of the main body column FD1, battery grip column FD2, and power condition column FD3 of the second power condition table TA2 is the same as that of the first power condition table TA1, so their explanation is omitted.

[0093] As shown in Figure 6, the second power condition table TA2 associates the connection relationship between the first terminal 301 and the second terminal 302 and the power supply device with power conditions 11 to 19. For example, the second power condition table TA2 associates power condition 17 with the state in which the internal coupler 210B is connected to the first terminal 301 and the external battery 220A is connected to the second terminal 302.

[0094] Figure 7 shows the third power condition table TA3, which associates the third connection relationships between each of the first terminal 301, the second terminal 302, and the USB terminal 190 with the power device, and power conditions 21 to 29. Specifically, the third connection relationship shows the connection relationships between each of the first terminal 301 and the second terminal 302 with the power device when a USB power device that does not support PD is connected to the USB terminal 190. Specifically, the third power condition table TA3 includes a main body column FD1, a battery grip column FD2, and a power condition column FD3, similar to the first power condition table TA1. Note that the configuration of the main body column FD1, battery grip column FD2, and power condition column FD3 of the third power condition table TA3 is the same as that of the first power condition table TA1, so its explanation is omitted.

[0095] As shown in Figure 7, the third power condition table TA3 associates the connection relationship between the first terminal 301 and the second terminal 302 and the power supply device with power conditions 21 to 29. For example, the third power condition table TA3 associates power condition 27 with the state in which the internal coupler 210B is connected to the first terminal 301 and the external battery 220A is connected to the second terminal 302.

[0096] As explained with reference to Figure 2, the first power control unit 310 identifies the current power condition that matches the current operating mode and current power information of the digital camera 100 from among the multiple power conditions registered in the first power condition table TA1 to the third power condition table TA3. For example, as shown in Figure 4, when the internal battery 210A is connected to the first terminal 301, the external battery 220A is connected to the second terminal 302, and a PD-compatible USB mobile battery MB is connected to the USB terminal 190, the first power control unit 310 identifies power condition 16 from among the multiple power conditions.

[0097] 2-1-2. Process for Identifying the Power Mode Next, the process for identifying the power mode will be explained with reference to Figures 8 to 11. Figure 8 is a diagram showing the first power mode table TA4 which associates power conditions 1 to 9, power modes 1 to 9, and power modes A to F. As shown in Figure 8, the first power mode table TA4 includes a power condition column FD11, a first power mode column FD12, and a second power mode column FD13.

[0098] The power condition field FD11 registers power conditions 1, 2, 3, 4, 5, 6-1, 6-2, 7, 8-1, 8-2, and 9. The first power mode field FD12 registers power modes 1, 2, 3, 4, 5, 6-1, 6-2, 7, 8-1, 8-2, and 9, associated with power conditions 1, 2, 3, 4, 5, 6-1, 6-2, 7, 8-1, 8-2, and 9. The second power mode field FD13 registers one of power modes A to F, associated with each of power modes 1, 2, 3, 4, 5, 6-1, 6-2, 7, 8-1, 8-2, and 9. For example, power mode C is associated with power mode 4.

[0099] Note that power supply conditions 6-1 and 6-2 correspond to power supply conditions 6 registered in the first power supply condition table TA1, as explained with reference to Figure 5. When the first power supply control unit 310 identifies power supply condition 6 by referring to the first power supply condition table TA1 to the third power supply condition table TA3, it selects one of power supply condition 6-1 or power supply condition 6-2.

[0100] For example, the first power control unit 310 may select one of power condition 6-1 and power condition 6-2 depending on the load power consumed by the camera system load unit 100A. For example, the first power control unit 310 may select power condition 6-1 when the load power is less than a threshold and select power condition 6-2 when the load power is equal to or greater than the threshold. Alternatively, the first power control unit 310 may select one of power condition 6-1 and power condition 6-2 depending on the operating mode of the digital camera 100. For example, the first power control unit 310 may select power condition 6-1 when the operating mode is still image shooting mode and select power condition 6-2 when the operating mode is video shooting mode.

[0101] Similarly, power supply conditions 8-1 and 8-2 correspond to power supply conditions 8 registered in the first power supply condition table TA1, as explained with reference to Figure 5. When the first power supply control unit 310 identifies power supply condition 8 by referring to the first power supply condition table TA1 to the third power supply condition table TA3, it selects one of power supply condition 8-1 or power supply condition 8-2.

[0102] For example, the first power control unit 310 may select one of power condition 8-1 and power condition 8-2 according to the load power consumed by the camera system load unit 100A, similar to power condition 6. Alternatively, the first power control unit 310 may select one of power condition 8-1 and power condition 8-2 according to the operating mode of the digital camera 100, similar to power condition 6.

[0103] Figure 9 shows a second power mode table TA5 that associates power conditions 11 to 19, power modes 11 to 19, and power modes A to F. As shown in Figure 9, the second power mode table TA5 includes a power condition column FD21, a first power mode column FD22, and a second power mode column FD23.

[0104] Power supply conditions FD21 contains the power supply conditions 11 to 19. Power supply modes 11 to 19 are registered in the first power supply mode field FD22, associated with the power supply conditions 11 to 19. Power supply modes 23 contains one of power supply modes A to F, associated with each of power supply modes 11 to 19. For example, power supply mode E is associated with power supply mode 18.

[0105] Figure 10 shows a third power mode table TA6 that associates power conditions 21 to 29, power modes 21 to 29, and power modes A to F. As shown in Figure 10, the third power mode table TA6 includes a power condition column FD31, a first power mode column FD32, and a second power mode column FD33.

[0106] Power supply conditions FD31 contains the power supply conditions 21 to 29. Power supply modes 21 to 29 are registered in the first power supply mode field FD32, associated with the power supply conditions 21 to 29. Power supply modes 21 to 29 are registered in the second power supply mode field FD33, associated with each of the power supply modes 21 to 29, and one of power supply modes A to F is registered. For example, power supply mode D is associated with power supply mode 28.

[0107] As explained with reference to Figure 2, the first power control unit 310 identifies a power mode that matches the current power conditions identified by referring to the first power condition tables TA1 to TA3, from among the multiple power modes (power modes A to F) registered in the first power mode table TA4 to TA6. For example, if the current power conditions identified by referring to the first power condition tables TA1 to TA3 are power condition 6, the first power control unit 310 selects either power condition 6-1 or power condition 6-2 to identify power mode C or D from among power modes A to F.

[0108] In Embodiment 1, the first power mode tables TA4 to TA6 are provided with first power mode fields FD12, FD22, and FD32, respectively, but the first power mode fields FD12, FD22, and FD32 may be omitted.

[0109] Alternatively, in other embodiments, the second power mode columns FD13, FD23, and FD33 may be omitted from the first power mode tables TA4 to the third power mode tables TA6. In this case, the fourth power mode table TA7 shown in Figure 11 may be further stored in the memory of the first power control unit 310. Figure 11 shows the fourth power mode table TA7 which associates power modes 1 to 5, 6-1, 6-2, 7, 8-1, 8-2, 9, 11 to 19, and 21 to 29 with power modes A to F. As shown in Figure 11, the fourth power mode table TA7 includes the first power mode column FD41 and the second power mode column FD42.

[0110] The first power mode field FD41 registers power modes A to F. The second power mode field FD42 registers power modes 1 to 5, 6-1, 6-2, 7, 8-1, 8-2, 9, 11 to 19, and 21 to 29, associated with power modes A to F. For example, power modes 12, 18, and 22 are associated with power mode E.

[0111] If the second power mode fields FD13, FD23, and FD33 are omitted from the first power mode table TA4 to the third power mode table TA6, the first power control unit 310 selects one of the power modes 1 to 5, 6-1, 6-2, 7, 8-1, 8-2, 9, 11 to 19, and 21 to 29 from the first power mode table TA4 to the third power mode table TA6, and then refers to the fourth power mode table TA7 to select one of the power modes A to F.

[0112] 2-2. Control of the First Power Switching Unit, the Second Power Switching Unit, and the State Transition Circuit Next, with reference to Figures 4 and 12, the control of the first power switching unit 330, the second power switching unit 350, and the state transition circuit 321 by the first power control unit 310 and the second power control unit 320 will be described.

[0113] Figure 12 shows a power supply switching table TA8 that associates power supply modes A to F, the states of the first FET 331, second FET 332, third FET 334, fourth FET 335, fifth FET 351, sixth FET 352, seventh FET 353, and eighth FET 354, with the state of the state transition circuit 321. As shown in Figure 12, the power supply switching table TA8 includes a power supply mode column FD51, a first switching column FD52, a second switching column FD53, a third switching column FD54, a fourth switching column FD55, and a fifth switching column FD56.

[0114] Power mode field FD51 registers power modes A to F. First switching field FD52 registers the on or off state of the first FET 331 and the on or off state of the second FET 332, associated with each of power modes A to F. Second switching field FD53 registers the on or off state of the third FET 334 and the on or off state of the fourth FET 335, associated with each of power modes A to F. Third switching field FD54 registers the on or off state of the fifth FET 351 and the on or off state of the sixth FET 352, associated with each of power modes A to F. Fourth switching field FD55 registers the on or off state of the seventh FET 353 and the on or off state of the eighth FET 354, associated with each of power modes A to F. In the fifth switching field FD56, the state of the state transition circuit 321 (first state or second state) is registered, associated with each of the power supply modes A to F.

[0115] For example, associated with power mode A, the following are registered: the first FET 331 is ON, the second FET 332 is OFF, the third FET 334 is ON, the fourth FET 335 is OFF, the fifth FET 351 is OFF, the sixth FET 352 is OFF, the seventh FET 353 is OFF, the eighth FET 354 is OFF, and the second state of the state transition circuit 321.

[0116] When the first power control unit 310 selects one of the power modes A to F, it controls the first FET 331, the second FET 332, the third FET 334, and the fourth FET 335 based on the selected power mode and the power switching table TA8.

[0117] Furthermore, when the first power control unit 310 selects one of the power modes A to F, it notifies the second power control unit 320 of the selected power mode. As a result, the second power control unit 320 controls the fifth FET 351, the sixth FET 352, the seventh FET 353, and the eighth FET 354 based on the power mode obtained from the first power control unit 310 and the power switching table TA8 stored in the memory of the second power control unit 320.

[0118] Furthermore, the second power control unit 320 instructs the state of the state transition circuit 321 (first state or second state) based on the power mode acquired from the first power control unit 310 and the power switching table TA8 stored in the memory of the second power control unit 320. As a result, the controller 323 matches the state of the state transition circuit 321 with the state instructed by the second power control unit 320.

[0119] For example, if the first power control unit 310 selects power mode A by referring to the first power mode table TA4 to the third power mode table TA6, the first power control unit 310 turns on the first FET 331, turns off the second FET 332, turns on the third FET 334, and turns off the fourth FET 335. The second power control unit 320 turns off the fifth FET 351 to the eighth FET 354. The controller 323 sets the state transition circuit 321 to the second state.

[0120] Therefore, when power mode A is selected, the USB terminal 190 is not electrically connected to the first power line 360. Then, the first power switching unit 330 selects either the first terminal 301 or the second terminal 302, and the power input from the selected terminal is supplied to the first power line 360 ​​via the state transition circuit 321.

[0121] Specifically, the diode OR circuit is formed when the first FET 331 is turned ON, the second FET 332 is turned OFF, the third FET 334 is turned ON, and the fourth FET 335 is turned OFF. As a result, the power with the higher voltage between the power input from the first terminal 301 and the power input from the second terminal 302 is supplied to the first power line 360 ​​via the state transition circuit 321.

[0122] Next, we will explain power mode B. As shown in Figures 4 and 12, when power mode B is selected, the first FET 331 and the second FET 332 are turned ON, and the third FET 334, the fourth FET 335, the fifth FET 351, the sixth FET 352, the seventh FET 353, and the eighth FET 354 are turned OFF, and the state transition circuit 321 enters the second state. As a result, the first power input to the first terminal 301 is supplied to the first power line 360 ​​via the second power line 370 (main unit priority mode).

[0123] Next, we will explain power mode C. As shown in Figures 4 and 12, when power mode C is selected, the first FET 331 and the second FET 332 are turned off, the third FET 334 and the fourth FET 335 are turned on, and the fifth FET 351, the sixth FET 352, the seventh FET 353, and the eighth FET 354 are turned off, and the state transition circuit 321 enters the second state. As a result, the second power input to the second terminal 302 is supplied to the first power line 360 ​​via the second power line 370 (battery grip priority mode). In power mode C, the second power output from the battery grip 103 is supplied to the first power line 360 ​​without passing through the step-up / step-down DC / DC converter 322. Therefore, power loss can be reduced.

[0124] Next, we will explain power mode D. As shown in Figures 4 and 12, when power mode D is selected, the first FET 331 and the second FET 332 are turned ON, the third FET 334 and the fourth FET 335 are turned OFF, the fifth FET 351 and the sixth FET 352 are turned ON, the seventh FET 353 and the eighth FET 354 are turned OFF, and the state transition circuit 321 enters the first state.

[0125] As a result, the second power input to the second terminal 302 is supplied to the first power line 360 ​​via the third power line 380. Also, because the state transition circuit 321 is in the first state (full-on state), if the second power supplied to the first power line 360 ​​via the third power line 380 is less than the load power, the first power input to the first terminal 301 is supplied to the first power line 360 ​​via the second power line 370. Therefore, power is supplied to the first power line 360 ​​simultaneously from both the third power line 380 and the second power line 370.

[0126] On the other hand, if the second power supplied to the first power line 360 ​​via the third power line 380 is greater than the load power, surplus power is generated in the second power supplied to the first power line 360 ​​via the third power line 380. In power mode D, the internal battery 210A is connected to the first terminal 301, the state transition circuit 321 is in the first state (full-on state), and the first FET 331 and the second FET 332 are in the ON state, so the surplus power is output from the first terminal 301 to the internal battery 210A, and the internal battery 210A is charged.

[0127] Next, we will explain power mode E. As shown in Figures 4 and 12, when power mode E is selected, the first FET 331 and the second FET 332 are turned ON, the third FET 334 and the fourth FET 335 are turned OFF, the fifth FET 351 and the sixth FET 352 are turned OFF, the seventh FET 353 and the eighth FET 354 are turned ON, and the state transition circuit 321 enters the first state.

[0128] As a result, the third power input to the USB terminal 190 is supplied to the first power line 360 ​​via the third power line 380. Also, since the state transition circuit 321 is in the first state (full-on state), if the third power supplied to the first power line 360 ​​via the third power line 380 is less than the load power, power is supplied to the first power line 360 ​​simultaneously from both the third power line 380 and the second power line 370, similar to power mode D.

[0129] Furthermore, in power mode E, similar to power mode D, the internal battery 210A is connected to the first terminal 301, the state transition circuit 321 is in the first state (fully on state), and the first FET 331 and the second FET 332 are on. Therefore, when surplus power is generated in the third power supplied to the first power line 360 ​​via the third power line 380, that surplus power is output from the first terminal 301 to the internal battery 210A, and the internal battery 210A is charged.

[0130] Next, we will explain power mode F. As shown in Figures 4 and 12, when power mode F is selected, the first FET 331 and the second FET 332 are turned off, the third FET 334 and the fourth FET 335 are turned on, the fifth FET 351 and the sixth FET 352 are turned off, the seventh FET 353 and the eighth FET 354 are turned on, and the state transition circuit 321 enters the first state.

[0131] As a result, the third power input to the USB terminal 190 is supplied to the first power line 360 ​​via the third power line 380. Also, when the state transition circuit 321 enters the first state (fully on state), the third FET 334 and the fourth FET 335 are turned on. Therefore, if the third power supplied to the first power line 360 ​​via the third power line 380 is less than the load power, the second power input to the second terminal 302 is supplied to the first power line 360 ​​via the second power line 370. Thus, the first power line 360 ​​is supplied with power simultaneously from both the third power line 380 and the second power line 370.

[0132] On the other hand, if the third power supplied to the first power line 360 ​​via the third power line 380 is greater than the load power, surplus power is generated in the third power supplied to the first power line 360 ​​via the third power line 380. In power mode F, the external battery 220A is connected to the second terminal 302, the state transition circuit 321 is in the first state (full-on state), and the third FET 334 and the fourth FET 335 are in the ON state, so the surplus power is output from the second terminal 302 to the external battery 220A, and the external battery 220A is charged.

[0133] In Embodiment 1, the state transition circuit 321 was set to the first state in power mode D, but as shown in Figure 13, in other embodiments, the state transition circuit 321 may be set to the second state in power mode D.

[0134] Figure 13 shows a part of another example of the power switching table TA8 that associates power modes A to F, the states of the first FET 331, second FET 332, third FET 334, fourth FET 335, fifth FET 351, sixth FET 352, seventh FET 353, and eighth FET 354, and the state of the state transition circuit 321. As shown in Figure 13, the second state of the state transition circuit 321 may be registered in the fifth switching column FD56 in association with power mode D. In this case, even if surplus power is generated, the internal battery 210A will not be charged.

[0135] Note that Figure 13 shows only the portion of the power switching table TA8 corresponding to power mode D, and omits the portions corresponding to power modes A to C, E, and F. In other examples of the power switching table TA8 shown in Figure 13, the portions corresponding to power modes A to C, E, and F are the same as those in the power switching table TA8 shown in Figure 12.

[0136] 2-3. Power Mode Transitions Next, the power mode transitions will be explained with reference to Figures 4 to 10, 12, and 14 to 17. Figures 14 to 16 are diagrams showing the power mode transitions of the digital camera 100 of Embodiment 1. Specifically, Figures 14 to 16 show the power mode transitions when the internal battery 210A is connected to the first terminal 301. The power mode transitions by the first power control unit 310 and the second power control unit 320 controlling the first power switching unit 330, the second power switching unit 350, and the state transition circuit 321.

[0137] For example, as shown in Figure 14, when the state of the digital camera 100 changes from a state where no power devices are connected to the first terminal 301, the second terminal 302, and the USB terminal 190, to a state where the internal battery 210A is connected to the first terminal 301, the power mode transitions from power mode 1 (power mode A) to power mode 2 (power mode B). As a result, the first power output from the internal battery 210A is supplied to the camera system load unit 100A.

[0138] When a PD-compatible USB power device is connected to the USB terminal 190 of the digital camera 100 in power mode 2 (power mode B), the power mode transitions to power mode 12 (power mode E), and the third power output from the PD-compatible USB power device is supplied to the camera system load unit 100A via the step-up / step-down DC / DC converter 322. In this case, if surplus power is generated, the internal battery 210A is charged by the surplus power.

[0139] When the external coupler 220B is connected to the second terminal 302 of the digital camera 100 while it is in power mode 12 (power mode E), power mode E is maintained (power mode 18). As a result, power supply from the PD-compatible USB power device takes priority over power supply from the external coupler 220B, and the third power output from the PD-compatible USB power device is supplied to the camera system load unit 100A via the step-up / step-down DC / DC converter 322. Similarly, when the external battery 220A is connected to the second terminal 302 of the digital camera 100 while it is in power mode 12 (power mode E), power mode E is maintained (power mode 16). Therefore, power supply from the PD-compatible USB power device takes priority over power supply from the external battery 220A, and the third power output from the PD-compatible USB power device is supplied to the camera system load unit 100A via the step-up / step-down DC / DC converter 322.

[0140] When a non-PD compatible USB power device is connected to the USB terminal 190 of the digital camera 100 in power mode 2 (power mode B), the power mode transitions to power mode 22 (power mode E), and the third power output from the non-PD compatible USB power device is supplied to the camera system load unit 100A via the step-up / step-down DC / DC converter 322. In this case, if surplus power is generated, the internal battery 210A is charged by the surplus power. On the other hand, if the third power supplied to the camera system load unit 100A via the step-up / step-down DC / DC converter 322 is less than the load power, power is supplied simultaneously from the non-PD compatible USB power device and the internal battery 210A.

[0141] When the external coupler 220B is connected to the second terminal 302 of the digital camera 100 in power mode 22 (power mode E), the power mode transitions to power mode 28 (power mode D). In power mode 28, the first power output from the internal battery 210A is input to the first terminal 301, the second power output from the external coupler 220B is input to the second terminal 302, and the third power output from a non-PD compatible USB power device is input to the USB terminal 190, with the third power being less than the second power.

[0142] When the power mode transitions to power mode D, the first power control unit 310 causes the first power switching unit 330 to select the first terminal 301, and the second power control unit 320 causes the second power switching unit 350 to select the second terminal 302. As a result, the second power input to the second terminal 302 from the external coupler 220B is supplied to the first power line 360 ​​via the step-up / step-down DC / DC converter 322.

[0143] In power mode D, if the second power supplied to the first power line 360 ​​via the step-up / step-down DC / DC converter 322 is less than the load power, both the first power and the second power are supplied simultaneously to the camera system load section 100A via the first power line 360.

[0144] On the other hand, if the second power supplied to the first power line 360 ​​via the step-up / step-down DC / DC converter 322 is greater than the load power, a portion of the second power via the step-up / step-down DC / DC converter 322 is supplied to the camera system load section 100A, and the surplus power of the second power is supplied from the first power switching section 330 to the internal battery 210A via the first terminal 301. Therefore, the internal battery 210A is charged by the surplus power.

[0145] Next, we will explain power mode 26 (power mode F). When an external battery 220A is connected to the second terminal 302 of the digital camera 100 in power mode 22 (power mode E), the power mode transitions to power mode 26 (power mode F). Therefore, the third power output from the non-PD compatible USB power device is supplied to the camera system load unit 100A via the step-up / step-down DC / DC converter 322. In this case, if surplus power is generated, the external battery 220A is charged by the surplus power. Also, if the third power supplied to the camera system load unit 100A via the step-up / step-down DC / DC converter 322 is less than the load power, power is supplied simultaneously from the non-PD compatible USB power device and the external battery 220A.

[0146] Next, power modes 8-1 and 8-2 will be explained. When the external coupler 220B is connected to the second terminal 302 of the digital camera 100 while it is in power mode 2 (power mode B), the power mode transitions to power mode 8-1 (power mode A) or power mode 8-2 (power mode D). Alternatively, when a PD-compatible USB power device is disconnected from the USB terminal 190 of the digital camera 100 while it is in power mode 18 (power mode E), the power mode transitions to power mode 8-1 (power mode A) or power mode 8-2 (power mode D). Furthermore, when a non-PD-compatible USB power device is disconnected from the USB terminal 190 of the digital camera 100 while it is in power mode 28 (power mode D), the power mode transitions to power mode 8-1 (power mode A) or power mode 8-2 (power mode D).

[0147] In Embodiment 1, whether to transition to power mode 8-1 or power mode 8-2 is predetermined by user operation. Specifically, the user decides whether to transition to power mode 8-1 or power mode 8-2 via a menu screen displayed on the LCD monitor 163.

[0148] In detail, the user operates the ON / OFF switch for the first mode setting, which is configured to transition to power mode 8-1 in normal mode and to power mode 8-2 in high-load mode. Here, normal mode includes, for example, still image shooting mode. High-load mode includes video shooting mode.

[0149] When the first mode setting is turned ON, the power mode transitions to power mode 8-1 (power mode A) in normal mode and to power mode 8-2 (power mode D) in high load mode. Here, power mode 8-1 and power mode 8-2 correspond to a state where the first power output from the internal battery 210A is input to the first terminal 301, the second power output from the external coupler 220B is input to the second terminal 302, and the third power is not input to the USB terminal 190. When the first mode setting is turned OFF, regardless of whether the operating mode is normal mode or high load mode, the power mode transitions to one of the predetermined power modes, power mode 8-1 or power mode 8-2.

[0150] When the power mode transitions to power mode A, the first power switching unit 330 functions as a diode OR circuit. In power mode 8-1, the voltage of the second power output from the external coupler 220B is greater than the voltage of the first power output from the internal battery 210A, so the first power switching unit 330 selects the second terminal 302. As a result, the second power output from the external coupler 220B is supplied to the camera system load unit 100A via the first power line 360. Also, since power mode 8-1 corresponds to the normal mode, the second power output from the external coupler 220B is greater than the load power. Therefore, the camera system load unit 100A can be driven by the second power alone.

[0151] On the other hand, in high-load mode, the second power supplied to the first power line 360 ​​may be less than the load power. In contrast, in Embodiment 1, the system transitions to power mode 8-2 (power mode D) in high-load mode. Therefore, the first power switching unit 330 selects the first terminal 301, and the second power switching unit 350 selects the second terminal 302. As a result, the first power and the second power via the step-up / step-down DC / DC converter 322 are supplied to the camera system load unit 100A via the first power line 360. Therefore, even if the second power supplied to the first power line 360 ​​is less than the load power, the camera system load unit 100A can still be driven.

[0152] Furthermore, even in high-load mode, the second power supplied to the first power line 360 ​​may be greater than the load power. In this case, a portion of the second power, via the step-up / step-down DC / DC converter 322, is supplied to the camera system load unit 100A via the first power line 360, and the surplus power is supplied from the first power switching unit 330 to the internal battery 210A via the first terminal 301. Therefore, the surplus power of the second power output from the external coupler 220B can charge the internal battery 210A.

[0153] Furthermore, according to Embodiment 1, even when the power mode is power mode 8-2 (power mode D) and an SSD (USB load device) is connected to the USB terminal 190, the first power and the second power via the step-up / step-down DC / DC converter 322 are supplied to the camera system load unit 100A, so that the camera system load unit 100A and the SSD can be driven.

[0154] Furthermore, when the power mode is power mode 8-2 (power mode D), even if a USB load device is connected to the USB terminal 190, if the power consumption of the USB load device is small, the second power supplied to the first power line 360 ​​may be greater than the load power. In this case, a portion of the second power via the step-up / step-down DC / DC converter 322 is supplied to the camera system load unit 100A, and the surplus power is supplied to the internal battery 210A, which is then charged by the surplus power.

[0155] Next, power modes 6-1 and 6-2 will be explained. When an external battery 220A is connected to the second terminal 302 of the digital camera 100 while it is in power mode 2 (power mode B), the power mode transitions to power mode 6-1 (power mode C) or power mode 6-2 (power mode D). Alternatively, when a PD-compatible USB power device is disconnected from the USB terminal 190 of the digital camera 100 while it is in power mode 16 (power mode E), the power mode transitions to power mode 6-1 (power mode C) or power mode 6-2 (power mode D). Furthermore, when a non-PD-compatible USB power device is disconnected from the USB terminal 190 of the digital camera 100 while it is in power mode 26 (power mode F), the power mode transitions to power mode 6-1 (power mode C) or power mode 6-2 (power mode D).

[0156] In Embodiment 1, whether to transition to power mode 6-1 or power mode 6-2 is predetermined by user operation, similar to power modes 8-1 and 8-2. Specifically, similar to power modes 8-1 and 8-2, the user operates the ON / OFF switch of the second mode setting, which is set to transition to power mode 6-1 in normal mode and to transition to power mode 6-2 in high-load mode.

[0157] When the second mode setting is turned ON, the power mode transitions to power mode 6-1 (power mode C) in normal mode and to power mode 6-2 (power mode D) in high load mode. Here, power modes 6-1 and 6-2 correspond to the state in which the first power output from the internal battery 210A is input to the first terminal 301, the second power output from the external battery 220A is input to the second terminal 302, and the third power is not input to the USB terminal 190. When the second mode setting is turned OFF, regardless of whether the operating mode is normal mode or high load mode, the power mode transitions to one of the predetermined power modes, power mode 6-1 or power mode 6-2. The first mode setting and the second mode setting may be the same mode setting.

[0158] When the power mode transitions to power mode C, the first power switching unit 330 selects the second terminal 302. As a result, the second power output from the external battery 220A is supplied to the camera system load unit 100A via the first power line 360. Furthermore, since power mode 6-1 corresponds to the normal mode, the second power output from at least a fully charged external battery 220A is greater than the load power. Therefore, the camera system load unit 100A can be driven by the second power alone.

[0159] On the other hand, in high-load mode, the second power supplied to the first power line 360 ​​may be less than the load power. In contrast, in Embodiment 1, the system transitions to power mode 6-2 (power mode D) in high-load mode. Therefore, the first power and the second power via the step-up / step-down DC / DC converter 322 are supplied to the camera system load unit 100A via the first power line 360. Thus, even if the second power supplied to the first power line 360 ​​is less than the load power, the camera system load unit 100A can still be driven.

[0160] Furthermore, even in high-load mode, the second power supplied to the first power line 360 ​​may be greater than the load power. In this case, the internal battery 210A can be charged by the surplus power of the second power output from the external battery 220A.

[0161] Furthermore, according to Embodiment 1, even when the power mode is power mode 6-2 (power mode D) and an SSD (USB load device) is connected to the USB terminal 190, the first power and the second power via the step-up / step-down DC / DC converter 322 are supplied to the camera system load unit 100A, so that the camera system load unit 100A and the SSD can be driven.

[0162] Furthermore, when the power mode is power mode 6-2 (power mode D), even if a USB load device is connected to the USB terminal 190, if the power consumption of the USB load device is small, the second power supplied to the first power line 360 ​​may be greater than the load power. In this case, a portion of the second power via the step-up / step-down DC / DC converter 322 is supplied to the camera system load unit 100A, and the surplus power is supplied to the internal battery 210A, where the internal battery 210A is charged by the surplus power.

[0163] Furthermore, in power mode D (power modes 8-2 and 6-2), when the first power is input to the first terminal 301, the second power is input to the second terminal 302, and the third power is not input to the USB terminal 190, the first power switching unit 330 selects the first terminal 301 and the second power switching unit 350 selects the second terminal 302. Therefore, when the power mode is power mode D (power mode 8-2 or power mode 6-2), even if the second power device (external coupler 220B or external battery 220A) is disconnected from the digital camera 100, the first power is supplied to the first power line 360 ​​via the second power line 370. Specifically, when the power mode is power mode D and the second power device is disconnected from the digital camera 100, the power mode transitions to power mode 2 (power mode B), and the first power is supplied to the camera system load unit 100A. Therefore, according to Embodiment 1, so-called "hot-swapping" can be achieved in the digital camera 100.

[0164] Furthermore, if the external battery 220A is removed from the digital camera 100 while it is in power mode 6-1 or power mode 6-2, the power mode will transition to power mode 2. Also, in the digital camera 100 while it is in power mode 6-1 or power mode 6-2, if the battery voltage of the external battery 220A drops below a predetermined voltage value (undercut voltage value), the power mode will transition to power mode 2. In addition, if the battery grip 103 is provided with a lid that the user opens and closes when inserting or removing the external battery 220A, and a detection mechanism or detection sensor that detects the opening and closing of the lid, the power mode may transition from power mode 6-1 or power mode 6-2 to power mode 2 in response to the opening of the lid of the battery grip 103.

[0165] Next, the transitions in power modes will be explained with reference to Figure 15. Figure 15 shows the transitions in power modes when the battery voltage of the internal battery 210A drops to a voltage value below a predetermined voltage value (undercut voltage value) from the state of power mode 8-1 (power mode A) or power mode 8-2 (power mode D).

[0166] As shown in Figure 15, in the digital camera 100 in power mode 8-1 (power mode A) or power mode 8-2 (power mode D), when the battery voltage of the internal battery 210A drops below a predetermined voltage value, the power mode transitions to power mode 5 (power mode C). As a result, the second power input from the external coupler 220B to the second terminal 302 is supplied to the camera system load unit 100A via the second power line 370 (battery grip priority mode).

[0167] Furthermore, when a PD-compatible USB power device is connected to the USB terminal 190 of the digital camera 100 in power mode 5 (power mode C), power mode C is maintained, and the second power output from the external coupler 220B is supplied to the camera system load unit 100A via the second power line 370 (battery grip priority mode). Similarly, when a non-PD-compatible USB power device is connected to the USB terminal 190 of the digital camera 100 in power mode 5 (power mode C), power mode C is maintained, and the second power output from the external coupler 220B is supplied to the camera system load unit 100A via the second power line 370 (battery grip priority mode).

[0168] Next, the transitions in power modes will be explained with reference to Figure 16. Figure 16 shows the transitions in power modes when the battery voltage of the internal battery 210A drops to a voltage value below a predetermined voltage value (undercut voltage value) from the state of power mode 6-1 (power mode C) or power mode 6-2 (power mode D).

[0169] As shown in Figure 16, in the digital camera 100 in power mode 6-1 (power mode C) or power mode 6-2 (power mode D), when the battery voltage of the internal battery 210A drops below a predetermined voltage value, the power mode transitions to power mode 4 (power mode C). As a result, the second power input from the external battery 220A to the second terminal 302 is supplied to the camera system load unit 100A via the second power line 370 (battery grip priority mode).

[0170] Furthermore, when a PD-compatible USB power device is connected to the USB terminal 190 of the digital camera 100 while it is in power mode 4 (power mode C), the power mode transitions to power mode 14 (power mode F), and the third power input from the PD-compatible USB power device to the USB terminal 190 is supplied to the camera system load unit 100A via the third power line 380. Similarly, when a non-PD-compatible USB power device is connected to the USB terminal 190 of the digital camera 100 while it is in power mode 4 (power mode C), the power mode transitions to power mode F (power mode 24), and the third power input from the non-PD-compatible USB power device to the USB terminal 190 is supplied to the camera system load unit 100A via the third power line 380.

[0171] Next, the transition of power modes will be explained with reference to Figure 17. Figure 17 is a diagram showing the transition of power modes when the internal coupler 210B is connected to the first terminal 301 included in the digital camera 100 of Embodiment 1.

[0172] For example, as shown in Figure 17, when the state changes from one where no power supply device is connected to the first terminal 301, the second terminal 302, and the USB terminal 190, to one where the internal coupler 210B is connected to the first terminal 301, the power mode transitions from power mode 1 (power mode A) to power mode 3 (power mode B). As a result, the first power output from the internal coupler 210B is supplied to the camera system load unit 100A.

[0173] If a PD-compatible USB power device is connected to the USB terminal 190 of the digital camera 100 while it is in power mode 3 (power mode B), the power mode will remain in power mode B (power mode 13). Similarly, if a non-PD-compatible USB power device is connected to the USB terminal 190 of the digital camera 100 while it is in power mode 3 (power mode B), the power mode will remain in power mode B (power mode 23).

[0174] When the external coupler 220B is connected to the second terminal 302 of the digital camera 100 in power mode 13 (power mode B), the power mode transitions to power mode 19 (power mode A). Therefore, the first power switching unit 330 functions as a diode OR circuit, and the power with the higher voltage value between the power output from the internal coupler 210B and the power output from the external coupler 220B is supplied to the camera system load unit 100A.

[0175] When an external battery 220A is connected to the second terminal 302 of the digital camera 100 in power mode 13 (power mode B), the power mode transitions to power mode 17 (power mode F). Therefore, the third power input to the USB terminal 190 from the PD-compatible USB power device is supplied to the camera system load unit 100A via the third power line 380. Also, if the third power supplied to the camera system load unit 100A via the third power line 380 is less than the load power, the second power input to the second terminal 302 from the external battery 220A is supplied to the camera system load unit 100A via the second power line 370. Therefore, the third power input to the USB terminal 190 and the second power input to the second terminal 302 are supplied to the camera system load unit 100A simultaneously. On the other hand, if the third power supplied to the camera system load unit 100A via the third power line 380 is greater than the load power, the surplus power is output from the second terminal 302 to the external battery 220A, and the external battery 220A is charged.

[0176] If a PD-compatible USB power device is disconnected from the USB terminal 190 of the digital camera 100 while it is in power mode 19 (power mode A), the power mode will remain in power mode A (power mode 9). Similarly, if a non-PD-compatible USB power device is connected to the USB terminal 190 of the digital camera 100 while it is in power mode 9 (power mode A), the power mode will remain in power mode A (power mode 29).

[0177] When a PD-compatible USB power device is disconnected from the USB terminal 190 of the digital camera 100 while it is in power mode 17 (power mode F), the power mode transitions to power mode 7 (power mode A). Therefore, the first power switching unit 330 functions as a diode OR circuit, and the power with the higher voltage value between the power output from the internal coupler 210B and the power output from the external battery 220A is supplied to the camera system load unit 100A.

[0178] If a USB power device that does not support PD is connected to the USB terminal 190 of the digital camera 100 while it is in power mode 7 (power mode A), the power mode will be maintained in power mode A (power mode 27).

[0179] 3. Effects, etc. Embodiment 1 of the present disclosure has been described above with reference to the drawings. According to Embodiment 1, a digital camera 100 or camera body 102, which is an example of an imaging device, captures an image of a subject. The digital camera 100 or camera body 102 includes a camera system load unit 100A, which is an example of a load unit, a first terminal 301, a second terminal 302, a USB terminal 190, which is an example of a third terminal, a first power supply line 360, which is an example of a power supply line, a first power switching unit 330, a second power switching unit 350, and a first power control unit 310 and a second power control unit 320, which are examples of control units. The camera system load unit 100A operates the digital camera 100 or camera body 102. An internal battery 210A or an internal coupler 210B, which is an example of a first power supply device that outputs first power, is connected to the first terminal 301. An external battery 220A or an external coupler 220B, which is an example of a second power supply device that outputs second power, is detachably connected to the second terminal 302. A USB power supply device (for example, a USB mobile battery MB), which is an example of a third power supply device that outputs third power, is detachably connected to the USB terminal 190. The first power line 360 ​​supplies load power to the camera system load unit 100A. The first power switching unit 330 selects either the first terminal 301 or the second terminal 302 and electrically connects it to the first power line 360. The second power switching unit 350 selects either the USB terminal 190 or the second terminal 302 and electrically connects it to the first power line 360. The first power control unit 310 and the second power control unit 320 control the first power switching unit 330 and the second power switching unit 350 to select either an electrical connection between the second terminal 302 and the first power line 360 ​​via the first power switching unit 330, or an electrical connection between the second terminal 302 and the first power line 360 ​​via the second power switching unit 350.

[0180] Therefore, according to Embodiment 1, when the load on the camera system load unit 100A increases, the first terminal 301 is electrically connected to the first power line 360 ​​via the first power switching unit 330, and the second terminal 302 is electrically connected to the first power line 360 ​​via the second power switching unit 350, so that power output from the internal battery 210A or internal coupler 210B and power output from the external battery 220A or external coupler 220B can be simultaneously supplied to the camera system load unit 100A. Thus, even if the load on the camera system load unit 100A increases, the digital camera 100 or camera body 102 can be operated stably.

[0181] Furthermore, according to Embodiment 1, when the first power is input to the first terminal 301, the second power is input to the second terminal 302, and the third power is not input to the USB terminal 190, and the second power supplied to the first power line 360 ​​is less than the load power, the first power switching unit 330 is instructed to select the first terminal 301, and the second power switching unit 350 is instructed to select the second terminal 302, thereby supplying the first power and the second power to the camera system load unit 100A via the first power line 360. Therefore, according to Embodiment 1, even if the load on the camera system load unit 100A increases, the digital camera 100 or the camera body 102 can be operated stably.

[0182] Furthermore, according to Embodiment 1, when the first power is input to the first terminal 301, the second power is input to the second terminal 302, and the third power is not input to the USB terminal 190, and the second power supplied to the first power line 360 ​​is greater than the load power, the first power switching unit 330 selects the second terminal 302, and the second power is supplied to the camera system load unit 100A via the first power line 360. Therefore, according to Embodiment 1, the camera system load unit 100A can be operated solely by the second power output from the external battery 220A or the external coupler 220B. Thus, the remaining capacity of the internal battery 210A is less likely to decrease. Also, according to Embodiment 1, the power output from the external battery 220A or the external coupler 220B can be supplied to the camera system load unit 100A without going through the step-up / step-down DC / DC converter 322. Therefore, power loss can be reduced.

[0183] Furthermore, according to Embodiment 1, when the first power is input to the first terminal 301, the second power is input to the second terminal 302, and the third power is not input to the USB terminal 190, and the second power supplied to the first power line 360 ​​is greater than the load power, the first power switching unit 330 is instructed to select the first terminal 301, and the second power switching unit 350 is instructed to select the second terminal 302, thereby supplying a portion of the second power to the camera system load unit 100A via the first power line 360, and supplying the surplus power of the second power from the first power switching unit 330 to the internal battery 210A via the first terminal 301. Therefore, according to Embodiment 1, during imaging operation, the internal battery 210A can be charged using the power output from the external battery 220A or the external coupler 220B.

[0184] Furthermore, according to Embodiment 1, a USB power device (e.g., a USB mobile battery MB) and a USB load device (e.g., an SSD), which is an example of a load device, are selectively connected to the USB terminal 190. When the USB load device is connected to the USB terminal 190, the load power increases and power is supplied from the USB terminal 190 to the USB load device. The first power control unit 310 and the second power control unit 320, when the first power is input to the first terminal 301, the second power is input to the second terminal 302, the USB load device is connected to the USB terminal 190, and the second power supplied to the first power line 360 ​​is less than the load power, cause the first power switching unit 330 to select the first terminal 301 and the second power switching unit 350 to select the second terminal 302, thereby supplying the first power and the second power to the camera system load unit 100A via the first power line 360. Therefore, according to Embodiment 1, even if a USB load device is connected to the USB terminal 190 and the camera system load unit 100A is made to perform an imaging operation, the digital camera 100 or the camera body 102 can be operated stably.

[0185] Furthermore, according to Embodiment 1, a USB power device (e.g., a USB mobile battery MB) and a USB load device (e.g., a smartphone) are selectively connected to the USB terminal 190. When a USB load device is connected to the USB terminal 190, the load power increases and power is supplied from the USB terminal 190 to the USB load device. The first power control unit 310 and the second power control unit 320, when the first power is input to the first terminal 301, the second power is input to the second terminal 302, a USB load device is connected to the USB terminal 190, and the second power supplied to the first power line 360 ​​is greater than the load power, cause the first power switching unit 330 to select the first terminal 301 and the second power switching unit 350 to select the second terminal 302, thereby supplying a portion of the second power to the camera system load unit 100A via the first power line 360, and supplying the surplus power of the second power from the first power switching unit 330 to the internal battery 210A via the first terminal 301. Therefore, according to Embodiment 1, when the power consumption of the USB load device is relatively small, the internal battery 210A can be charged during imaging operation with the USB load device connected to the USB terminal 190.

[0186] Furthermore, according to Embodiment 1, when the first power is input to the first terminal 301, the second power is input to the second terminal 302, and a third power smaller than the second power is input to the USB terminal 190, and the second power supplied to the first power line 360 ​​is smaller than the load power, the first power switching unit 330 is instructed to select the first terminal 301 and the second power switching unit 350 is instructed to select the second terminal 302, thereby supplying the first power and the second power to the camera system load unit 100A via the first power line 360. Therefore, even if the load on the camera system load unit 100A increases when the power output from the USB power device is relatively small, the digital camera 100 or the camera body 102 can be operated stably.

[0187] Furthermore, according to Embodiment 1, when the first power is input to the first terminal 301, the second power is input to the second terminal 302, and a third power smaller than the second power is input to the USB terminal 190, and the second power supplied to the first power line 360 ​​is greater than the load power, the first power switching unit 330 is instructed to select the first terminal 301, and the second power switching unit 350 is instructed to select the second terminal 302, thereby supplying a portion of the second power to the camera system load unit 100A via the first power line 360, and supplying the surplus power of the second power from the first power switching unit 330 to the first power device via the first terminal 301. Therefore, according to Embodiment 1, when the power output from the USB power device (for example, a USB power device that does not support PD) is relatively small, the internal battery 210A can be charged using the power output from the external battery 220A or the external coupler 220B.

[0188] Furthermore, according to Embodiment 1, when the first power supply control unit 310 and the second power supply control unit 320 are in a state where the first power is input to the first terminal 301, the second power supply is input to the second terminal 302, and the third power supply is not input to the USB terminal 190, the first power supply switching unit 330 is instructed to select the first terminal 301 and the second power supply switching unit 350 is instructed to select the second terminal 302. Therefore, according to Embodiment 1, when the digital camera 100 or camera body 102 is being operated by supplying power output from the external battery 220A or external coupler 220B to the camera system load unit 100A, power output from the internal battery 210A or internal coupler 210B is supplied to the camera system load unit 100A in response to the external battery 220A or external coupler 220B being disconnected from the digital camera 100 or camera body 102. Thus, according to Embodiment 1, so-called "hot-swapping" can be realized in the digital camera 100. As a result, the digital camera 100 or the camera body 102 can be operated stably.

[0189] Furthermore, according to Embodiment 1, a digital camera 100 or camera body 102, which is an example of an imaging device, captures an image of a subject. The digital camera 100 or camera body 102 includes a camera system load unit 100A, which is an example of a load unit; a first terminal 301; a second terminal 302; a USB terminal 190, which is an example of a third terminal; a first power supply line 360, which is an example of a power supply line; and a first power control unit 310 and a second power control unit 320, which are examples of control units. The camera system load unit 100A operates the digital camera 100 or camera body 102. An internal battery 210A or internal coupler 210B, which is an example of a first power supply device that outputs first power, is connected to the first terminal 301. An external battery 220A or external coupler 220B, which is an example of a second power supply device that outputs second power, is detachably connected to the second terminal 302. A USB power device (for example, a USB mobile battery MB), which is an example of a third power supply device that outputs third power, is detachably connected to the USB terminal 190. The first power line 360 ​​supplies load power to the camera system load unit 100A. When the first power is input to the first terminal 301, the second power is input to the second terminal 302, and the third power is not input to the USB terminal 190, and the second power supplied to the first power line 360 ​​is greater than the load power, the first power control unit 310 and the second power control unit 320 supply a portion of the second power to the camera system load unit 100A via the first power line 360, and the surplus power of the second power is supplied to the internal battery 210A via the first terminal 301. Therefore, according to Embodiment 1, during imaging operation, the internal battery 210A can be charged using power output from the external battery 220A or the external coupler 220B.

[0190] Furthermore, according to Embodiment 1, a digital camera 100 or camera body 102, which is an example of an imaging device, captures an image of a subject. The digital camera 100 or camera body 102 includes a camera system load unit 100A, which is an example of a load unit; a first terminal 301; a second terminal 302; a USB terminal 190, which is an example of a third terminal; a first power supply line 360, which is an example of a power supply line; a first power switching unit 330; a second power switching unit 350; and a first power control unit 310 and a second power control unit 320, which are examples of control units. The camera system load unit 100A operates the digital camera 100 or camera body 102. An internal battery 210A or internal coupler 210B, which is an example of a first power supply device that outputs first power, is connected to the first terminal 301. An external battery 220A or external coupler 220B, which is an example of a second power supply device that outputs second power, is detachably connected to the second terminal 302. A USB power device (for example, a USB mobile battery MB), which is an example of a third power supply device that outputs a third power, is detachably connected to the USB terminal 190. The first power line 360 ​​supplies load power to the camera system load unit 100A. The first power switching unit 330 selects either the first terminal 301 or the second terminal 302 and electrically connects it to the first power line 360. The second power switching unit 350 selects either the USB terminal 190 or the second terminal 302 and electrically connects it to the first power line 360. When the first power is input to the first terminal 301, the second power is input to the second terminal 302, and the third power is not input to the USB terminal 190, the first power control unit 310 and the second power control unit 320 cause the first power switching unit 330 to select the first terminal 301 and the second power switching unit 350 to select the second terminal 302.

[0191] Therefore, according to Embodiment 1, when the digital camera 100 or camera body 102 is being operated by supplying power output from the external battery 220A or external coupler 220B to the camera system load unit 100A, power output from the internal battery 210A or internal coupler 210B can be supplied to the camera system load unit 100A in response to the external battery 220A or external coupler 220B being disconnected from the digital camera 100 or camera body 102. Thus, according to Embodiment 1, so-called "hot-swapping" can be achieved in the digital camera 100. As a result, the digital camera 100 or camera body 102 can be operated stably.

[0192] [Embodiment 2] Next, Embodiment 2 of the present disclosure will be described with reference to Figures 18 to 23B. However, only matters that differ from Embodiment 1 will be described, and matters that are the same as Embodiment 1 will be omitted. Embodiment 2 differs from Embodiment 1 in that, when power is supplied simultaneously from the internal battery 210A and the external battery 220A to the camera system load unit 100A, the current supplied from the external battery 220A (second terminal 302) to the first power line 360 ​​via the second power switching unit 350 is controlled so that the remaining capacity of the internal battery 210A and the external battery 220A is depleted at approximately the same time.

[0193] In the following, the current supplied from the internal battery 210A may be referred to as "first battery current BJ1," and the current supplied from the external battery 220A may be referred to as "second battery current BJ2." Similarly, the voltage supplied from the internal battery 210A may be referred to as "first battery voltage V1," and the voltage supplied from the external battery 220A may be referred to as "second battery voltage V2." Furthermore, the power supplied from the internal battery 210A may be referred to as "first battery power BE1," and the power supplied from the external battery 220A may be referred to as "second battery power BE2." In addition, the remaining capacity of the internal battery 210A may be referred to as "first battery remaining capacity BR1," and the remaining capacity of the external battery 220A may be referred to as "second battery remaining capacity BR2."

[0194] 4. Diagram 18 shows the configuration of the power supply control unit 300 included in the digital camera 100 of Embodiment 2. Diagram 19 shows the configuration of the first power supply switching unit 330, the second power supply switching unit 350, and the second power supply control unit 320 included in the digital camera 100 of Embodiment 2.

[0195] In Embodiment 2, when the first power supply control unit 310 is configured such that the internal battery 210A is connected to the first terminal 301 and the external battery 220A is connected to the second terminal 302, and a first operating mode with relatively low power consumption, such as still image shooting mode, is selected as the operating mode of the digital camera 100, it performs standalone power supply control. Specifically, the first power supply control unit 310 compares the remaining charge of the first battery BR1 and the remaining charge of the second battery BR2 to identify the battery with the higher remaining charge BR between the internal battery 210A and the external battery 220A. The first power supply control unit 310 then controls the first power supply switching unit 330 so that only the terminal to which the identified battery is connected is electrically connected to the first power line 360 ​​via the first power supply switching unit 330, and also controls the second power supply switching unit 350 via the second power supply control unit 320. In other words, the first power control unit 310 electrically connects the internal battery 210A to the first power line 360 ​​when the remaining charge of the first battery BR1 is greater than the remaining charge of the second battery BR2. When the remaining charge of the second battery BR2 is greater than the remaining charge of the first battery BR1, the first power control unit 310 electrically connects the external battery 220A to the first power line 360.

[0196] Hereinafter, the state in which the internal battery 210A is connected to the first terminal 301 and the external battery 220A is connected to the second terminal 302 may be referred to as the "battery connected state".

[0197] Furthermore, if the remaining charge of the first battery BR1 and the remaining charge of the second battery BR2 are equal, the first power control unit 310 may select one of the first terminal 301 and the second terminal 302 based on pre-set information. For example, information may be pre-set to select the first terminal 301 (internal battery 210A) when the remaining charge of the first battery BR1 and the remaining charge of the second battery BR2 are equal.

[0198] Furthermore, in Embodiment 2, when the battery is connected, if a second operating mode with relatively high power consumption, such as video recording mode, is selected as the operating mode of the digital camera 100, the first power supply control unit 310 performs capacity balancing power supply control.

[0199] The second operating mode is an operating mode in which the load power is greater than that of the first operating mode. In addition to the video recording mode, the second operating mode includes modes such as recording video data to a USB load device such as an SSD.

[0200] Capacity balancing power supply control includes a first simultaneous power supply control and a second simultaneous power supply control. Specifically, the first power supply control unit 310 executes the first simultaneous power supply control when both the remaining charge of the first battery BR1 and the remaining charge of the second battery BR2 are equal to or greater than the remaining charge threshold. The first power supply control unit 310 executes the second simultaneous power supply control when both the remaining charge of the first battery BR1 and the remaining charge of the second battery BR2 are less than the remaining charge threshold. The remaining charge threshold is preset. The remaining charge threshold is stored, for example, in the memory of the first power supply control unit 310.

[0201] Specifically, when the first simultaneous power supply control is executed, the first power supply control unit 310 causes the first power switching unit 330 to select the first terminal 301, thereby electrically connecting the first power line 360 ​​and the first terminal 301 via the first power switching unit 330, and also causes the second power switching unit 350 to select the second terminal 302 via the second power supply control unit 320, thereby electrically connecting the first power line 360 ​​and the second terminal 302 via the second power switching unit 350. Therefore, the first simultaneous power supply control ensures that the first battery supply power BE1 and the second battery supply power BE2 are simultaneously supplied to the camera system load unit 100A.

[0202] The first power control unit 310 further controls the second battery current BJ2 ​​when executing the first simultaneous power supply control, based on the first battery level BR1, the second battery level BR2, the first battery supply power BE1, and the second battery supply power BE2, so that the ratio of the first battery supply power BE1 to the second battery supply power BE2 [BE1 / BE2] matches the ratio of the first battery level BR1 to the second battery level BR2 [BR1 / BR2], as shown in the following equation (1). In Embodiment 2, the first power control unit 310 causes the second power control unit 320 to control the second battery current BJ2. BE1 / BE2 = BR1 / BR2 ... (1)

[0203] More specifically, the first power control unit 310 controls the second battery current BJ2 ​​based on the first battery charge BR1, the second battery charge BR2, the first battery current BJ1, the first battery voltage V1, and the second battery voltage V2, so that the ratio of the first battery supply power BE1 to the second battery supply power BE2 matches the ratio of the first battery charge BR1 to the second battery charge BR2. That is, equation (1) above can be converted to equation (2) below using the first battery current BJ1, the first battery voltage V1, the second battery current BJ2, and the second battery voltage V2. Therefore, the second power control unit 320 controls the second battery current BJ2 ​​based on equation (3) derived from equation (2), so that the ratio of the first battery supply power BE1 to the second battery supply power BE2 matches the ratio of the remaining charge of the first battery BR1 to the remaining charge of the second battery BR2. (BJ1 × V1) / (BJ2 × V2) = BR1 / BR2 ... (2) BJ2 = (BJ1 × V1 × BR2) / (V2 × BR1) ... (3)

[0204] Next, the second simultaneous power supply control will be explained. When the second simultaneous power supply control is executed, the first power supply control unit 310 supplies the first battery supply power BE1 and the second battery supply power BE2 to the camera system load unit 100A simultaneously, similar to the first simultaneous power supply control. On the other hand, unlike the first simultaneous power supply control, the first power supply control unit 310 performs fixed current ratio control in the second simultaneous power supply control. Specifically, the first power supply control unit 310 causes the second power supply control unit 320 to control the second battery current BJ2 ​​based on the first battery current BJ1, so that the ratio of the first battery current BJ1 to the second battery current BJ2 ​​is equal, as shown in equation (4) below. In other words, the first power supply control unit 310 causes the second power supply control unit 320 to control the second battery current BJ2 ​​so that the ratio of the first battery current BJ1 to the second battery current BJ2 ​​[BJ1:BJ2] is [1:1]. BJ2=BJ1... (4)

[0205] Next, we will further explain capacity-balanced power supply control. Capacity-balanced power supply control includes single-unit power supply control in addition to the first simultaneous power supply control and the second simultaneous power supply control. Specifically, the first power supply control unit 310 executes single-unit power supply control when only one of the first battery charge BR1 or the second battery charge BR2 is above the remaining charge threshold. Specifically, the first power supply control unit 310 identifies the battery whose battery charge BR is above the remaining charge threshold from among the internal battery 210A and the external battery 220A. In other words, the first power supply control unit 310 identifies the battery with the larger battery charge BR from among the internal battery 210A and the external battery 220A. The first power control unit 310 controls the first power switching unit 330 so that only the terminal to which the specified battery is connected among the first terminal 301 and the second terminal 302 is electrically connected to the first power line 360 ​​via the first power switching unit 330, and also controls the second power switching unit 350 via the second power control unit 320.

[0206] Here, with reference to Figures 18 and 19, an example of a configuration in which the first power control unit 310 acquires the first battery charge BR1, the second battery charge BR2, the first battery voltage V1, the second battery voltage V2, the first battery current BJ1, and the second battery current BJ2 ​​will be described.

[0207] As shown in Figure 18, in Embodiment 2, when the internal battery 210A is connected to the first terminal 301, information of the first battery charge BR1 is input from the internal battery 210A to the first power control unit 310. Similarly, when the external battery 220A is connected to the second terminal 302, information of the second battery charge BR2 is input from the external battery 220A to the first power control unit 310. For example, the internal battery 210A and the external battery 220A may have built-in integrated circuits (ICs) that calculate and output the battery charge BR.

[0208] Furthermore, in Embodiment 2, a branch line electrically connected to the first terminal 301 is electrically connected to the first power control unit 310, and when an internal battery 210A is connected to the first terminal 301, the first battery voltage V1 is input to the first power control unit 310, and the first power control unit 310 detects the first battery voltage V1. Similarly, a branch line electrically connected to the second terminal 302 is electrically connected to the first power control unit 310, and when an external battery 220A is connected to the second terminal 302, the second battery voltage V2 is input to the first power control unit 310, and the first power control unit 310 detects the second battery voltage V2.

[0209] As shown in Figure 19, in Embodiment 2, the second power supply control unit 320 further includes a first voltage measurement circuit 324, a resistor element 325, and a second voltage measurement circuit 326.

[0210] The first voltage measurement circuit 324 measures the drain-source voltage of the Nch type MOSFET 321a and outputs the measurement result to the first power supply control unit 310. The first power supply control unit 310 measures (calculates) the first battery current BJ1 based on the on-resistance of the Nch type MOSFET 321a and the measurement value from the first voltage measurement circuit 324.

[0211] In more detail, when the first battery power supply BE1 and the second battery power supply BE2 are supplied simultaneously to the camera system load section 100A, the voltage input from the internal battery 210A to the first terminal 301 passes through the ON-state N-channel MOSFET 321a and is supplied to the first power line 360. Therefore, the first battery current BJ1 can be measured (calculated) by measuring the drain-source voltage of the N-channel MOSFET 321a.

[0212] The first voltage measurement circuit 324 may be externally connected to the second power supply control unit 320.

[0213] The resistive element 325 is provided on the power line that electrically connects the second power switching unit 350 and the step-up / step-down DC / DC converter 322. The second voltage measurement circuit 326 measures the voltage across the resistive element 325 and outputs the measurement result to the first power control unit 310. The measurement result indicates the voltage input to the step-up / step-down DC / DC converter 322. The first power control unit 310 measures (calculates) the second battery current BJ2 ​​based on the resistance value of the resistive element 325 and the measurement value of the second voltage measurement circuit 326.

[0214] In more detail, when the first battery power supply BE1 and the second battery power supply BE2 are simultaneously supplied to the camera system load unit 100A, the voltage input from the external battery 220A to the second terminal 302 is supplied to the first power line 360 ​​via the step-up / step-down DC / DC converter 322. Therefore, the second battery current BJ2 ​​can be measured (calculated) by measuring the voltage input to the step-up / step-down DC / DC converter 322.

[0215] The resistive element 325 and the second voltage measurement circuit 326 may be externally connected to the second power supply control unit 320.

[0216] Next, the configuration for controlling the second battery current BJ2 ​​will be described. In Embodiment 2, the first power control unit 310 controls the second battery current BJ2 ​​by ​​changing the current value of the current supplied from the step-up / step-down DC / DC converter 322 to the first power line 360. In Embodiment 2, the step-up / step-down DC / DC converter 322 is an example of a "current control circuit" and controls the current supplied from the external battery 220A to the first power line 360 ​​via the second power switching unit 350.

[0217] Specifically, the current value output from the step-up / step-down DC / DC converter 322 is set in the controller 323. The controller 323 controls the step-up / step-down DC / DC converter 322 so that the set current value is output from the step-up / step-down DC / DC converter 322.

[0218] When the first simultaneous power supply control is executed, the first power supply control unit 310 changes the current value set in the controller 323 based on the first battery level BR1, the second battery level BR2, the first battery voltage V1, the second battery voltage V2, and the first battery current BJ1, so that the ratio of the first battery supply power BE1 to the second battery supply power BE2 matches the ratio of the first battery level BR1 to the second battery level BR2. As a result, the second battery current BJ2 ​​is controlled so that the ratio of the first battery supply power BE1 to the second battery supply power BE2 matches the ratio of the first battery level BR1 to the second battery level BR2.

[0219] Furthermore, when the second simultaneous power supply control is executed, the first power supply control unit 310 changes the current value set by the controller 323 based on the measured value of the first battery current BJ1 so that the ratio of the first battery current BJ1 to the second battery current BJ2 ​​becomes equal. As a result, the second battery current BJ2 ​​is controlled so that the ratio of the first battery current BJ1 to the second battery current BJ2 ​​becomes equal.

[0220] According to Embodiment 2, when the battery level BR of the internal battery 210A and the battery level BR of the external battery 220A are both above a remaining charge threshold, the first simultaneous power supply control is executed, and the second battery current BJ2 ​​is controlled so that the battery level BR of the internal battery 210A and the battery level BR of the external battery 220A reach the remaining charge threshold at approximately the same time. Then, when the battery level BR of the internal battery 210A and the battery level BR of the external battery 220A fall below the remaining charge threshold, the second simultaneous power supply control is executed, and the second battery current BJ2 ​​is controlled so that the battery level BR of the internal battery 210A and the battery level BR of the external battery 220A are depleted at approximately the same time. This makes it possible to increase the length of time during which the digital camera 100 can be operated without replacing the internal battery 210A and the external battery 220A.

[0221] 5. Power Modes Next, the power modes will be described with reference to Figure 20. Figure 20 is a diagram showing a part of the power switching table TA9 stored in the memory of the first power control unit 310 included in the digital camera 100 of Embodiment 2. In detail, Figure 20 shows power modes B, C, and D.

[0222] As shown in Figure 20, the information registered in the power switching table TA9 in association with power modes B and C is the same as that registered in the power switching table TA8 shown in Figure 12. The information registered in the power switching table TA9 in association with power mode D is the same as that registered in the power switching table TA8 shown in Figure 13. That is, in Embodiment 2, the second state of the state transition circuit 321 is registered in the fifth switching column FD56 in association with power mode D. Therefore, even if the second battery supply power BE2 is greater than the load power, the internal battery 210A is not charged.

[0223] When the battery is connected and the first operating mode is selected, the first power control unit 310 performs standalone power supply control and compares the first battery charge BR1 and the second battery charge BR2. If the comparison shows that the first battery charge BR1 is greater than the second battery charge BR2, the first power control unit 310 selects power mode B so that the first battery supply power BE1 is supplied to the camera system load unit 100A with priority over the second battery supply power BE2. On the other hand, if the comparison shows that the second battery charge BR2 is greater than the first battery charge BR1, the first power control unit 310 selects power mode C so that the second battery supply power BE2 is supplied to the camera system load unit 100A with priority over the first battery supply power BE1.

[0224] When the second operating mode is selected while the battery is connected, the first power control unit 310 performs capacity balancing power supply control and compares the remaining charge of the first battery BR1 and the remaining charge of the second battery BR2 with the remaining charge threshold. If the comparison shows that both the remaining charge of the first battery BR1 and the remaining charge of the second battery BR2 are equal to or greater than the remaining charge threshold, the first power control unit 310 performs first simultaneous power supply control and selects power mode D so that the first battery supply power BE1 and the second battery supply power BE2 are supplied to the camera system load unit 100A simultaneously. If the comparison shows that both the remaining charge of the first battery BR1 and the remaining charge of the second battery BR2 are less than the remaining charge threshold, the second simultaneous power supply control is performed and power mode D is selected, similar to the first simultaneous power supply control. On the other hand, if the comparison shows that only one of the remaining charge of the first battery BR1 or the remaining charge of the second battery BR2 is equal to or greater than the remaining charge threshold, the first power control unit 310 performs single power supply control and selects power mode B or power mode C.

[0225] Note that in Figure 20, only the parts of the power switching table TA9 corresponding to power modes B, C, and D are shown, while the parts corresponding to power modes A, E, and F are omitted. In the power switching table TA9 shown in Figure 20, the parts corresponding to power modes A, E, and F are the same as those in the power switching table TA8 shown in Figure 12.

[0226] 6. Operation 6-1. Power Supply Operation Next, with reference to Figures 21 and 22, the processes performed by the first power supply control unit 310 will be described.

[0227] Figure 21 is a flowchart showing the standalone power supply control performed by the first power supply control unit 310 included in the digital camera 100 of Embodiment 2. More specifically, Figure 21 shows the standalone power supply control performed in the first operating mode.

[0228] As shown in Figure 21, when the first power supply control unit 310 starts independent power supply control, it acquires information on the remaining charge of the first battery BR1 and the remaining charge of the second battery BR2 (S11), and prioritizes supplying power to the camera system load unit 100A from the battery with the higher remaining charge BR (S12), and then terminates the process shown in Figure 21.

[0229] The first power control unit 310 repeats the process shown in Figure 21 until the operating mode of the digital camera 100 transitions from the first operating mode to another operating mode. Alternatively, the first power control unit 310 repeats the process shown in Figure 21 until the power switch 152 accepts a power-off operation. Alternatively, the first power control unit 310 repeats the process shown in Figure 21 until the internal battery 210A is disconnected from the first terminal 301 or the external battery 220A is disconnected from the second terminal 302.

[0230] Figure 22 is a flowchart showing the capacity balancing power supply control performed by the first power supply control unit 310 included in the digital camera 100 of Embodiment 2.

[0231] As shown in Figure 22, when the first power supply control unit 310 starts capacity balancing power supply control, it acquires information on the remaining charge of the first battery BR1 and the remaining charge of the second battery BR2 (S21), and determines whether both the remaining charge of the first battery BR1 and the remaining charge of the second battery BR2 are below the remaining charge threshold (S22). The remaining charge threshold is, for example, 10%.

[0232] If the first power control unit 310 determines that both the first battery charge BR1 and the second battery charge BR2 are not below the remaining charge threshold (No in S22), that is, if it determines that at least one of the first battery charge BR1 and the second battery charge BR2 is equal to or greater than the remaining charge threshold, it determines whether both the first battery charge BR1 and the second battery charge BR2 are equal to or greater than the remaining charge threshold (S23).

[0233] When the first power control unit 310 determines that both the remaining charge of the first battery BR1 and the remaining charge of the second battery BR2 are above the remaining charge threshold (YES in S23), it executes the first simultaneous power supply control. As a result, power is supplied to the camera system load unit 100A from both the internal battery 210A and the external battery 220A. Furthermore, the first power control unit 310 controls the second battery current BJ2 ​​according to the remaining charge of the first battery BR1 and the remaining charge of the second battery BR2 (S24). Specifically, the first power control unit 310 controls the second battery current BJ2 ​​so that the ratio of the first battery supply power BE1 to the second battery supply power BE2 matches the ratio of the remaining charge of the first battery BR1 to the remaining charge of the second battery BR2. After executing the first simultaneous power supply control, the first power control unit 310 terminates the process shown in Figure 22.

[0234] If the first power supply control unit 310 determines that both the remaining charge of the first battery BR1 and the remaining charge of the second battery BR2 are not above the remaining charge threshold (NO in S23), that is, if it determines that one of the remaining charge of the first battery BR1 or the remaining charge of the second battery BR2 is below the remaining charge threshold, it executes single-unit power supply control and prioritizes supplying power to the camera system load unit 100A from the battery whose remaining charge BR is above the remaining charge threshold (S25), and terminates the process shown in Figure 22.

[0235] On the other hand, if the first power supply control unit 310 determines that both the remaining charge of the first battery BR1 and the remaining charge of the second battery BR2 are below the remaining charge threshold (YES in S22), it executes the second simultaneous power supply control. As a result, power is supplied to the camera system load unit 100A from both the internal battery 210A and the external battery 220A. Furthermore, the first power supply control unit 310 executes current ratio fixed control. As a result, the second battery current BJ2 ​​is controlled so that the ratio of the first battery current BJ1 to the second battery current BJ2 ​​becomes equal. After executing the second simultaneous power supply control, the first power supply control unit 310 terminates the process shown in Figure 22.

[0236] The first power control unit 310 repeats the process shown in Figure 22 until the operating mode of the digital camera 100 transitions from the second operating mode to another operating mode. Alternatively, the first power control unit 310 repeats the process shown in Figure 22 until the power switch 152 accepts a power-off operation. Alternatively, the first power control unit 310 repeats the process shown in Figure 22 until the internal battery 210A is disconnected from the first terminal 301 or the external battery 220A is disconnected from the second terminal 302.

[0237] As described above with reference to Figures 18 to 22, according to Embodiment 2, in the second operating mode, power can be supplied to the camera system load unit 100A from the internal battery 210A and the external battery 220A. Therefore, the digital camera 100 can be operated stably.

[0238] Furthermore, according to Embodiment 2, in the second operating mode, the power BE1 supplied from the internal battery 210A and the power BE2 supplied from the external battery 220A can be adjusted according to the ratio of the remaining capacity BR1 of the internal battery 210A and the remaining capacity BR2 of the external battery 220A. Therefore, the power BE1 supplied from the internal battery 210A and the power BE2 supplied from the external battery 220A can be adjusted so that the remaining capacity BR1 of the internal battery 210A and the remaining capacity BR2 of the external battery 220A are depleted at approximately the same time. As a result, the length of time during which the digital camera 100 can be operated without replacing the internal battery 210A and the external battery 220A can be increased.

[0239] Furthermore, in Embodiment 2, a remaining charge threshold of 10% is set. Generally, the voltage output from the battery (discharge voltage) decreases sharply when the battery charge BR falls below 10%. Therefore, when both the first battery charge BR1 and the second battery charge BR2 are below 10%, even if information on the first battery charge BR1 and the second battery charge BR2 is acquired and an attempt is made to control the second battery current BJ2 ​​so that the ratio of the first battery supply power BE1 to the second battery supply power BE2 matches the ratio of the first battery charge BR1 to the second battery charge BR2, it becomes difficult to control the second battery current BJ2 ​​to keep up with the sharp changes in the first battery voltage V1 and the second battery voltage V2.

[0240] In contrast, according to Embodiment 2, when both the remaining charge of the first battery BR1 and the remaining charge of the second battery BR2 fall below the remaining charge threshold, the second battery current BJ2 ​​is controlled based on the first battery current BJ1 so that the ratio of the first battery current BJ1 to the second battery current BJ2 ​​becomes equal (current ratio fixed control). Therefore, since the only value referenced is the first battery current BJ1, it becomes possible to make the control of the second battery current BJ2 ​​follow sharp changes in the first battery voltage V1 and the second battery voltage V2.

[0241] Furthermore, according to Embodiment 2, when both the remaining capacity of the first battery BR1 and the remaining capacity of the second battery BR2 fall below the remaining capacity threshold, the ratio of the first battery current BJ1 to the second battery current BJ2 ​​becomes equal. Therefore, power BE is supplied from the internal battery 210A and the external battery 220A such that the remaining capacity BR1 of the internal battery 210A and the remaining capacity BR2 of the external battery 220A are depleted at approximately the same time. As a result, the length of time during which the digital camera 100 can be operated without replacing the internal battery 210A and the external battery 220A can be increased.

[0242] 6-2. Undercut Voltage Change Processing Next, the processing performed by the first power control unit 310 will be explained with reference to Figures 23A and 23B. Figure 23A is a diagram showing the time change of the battery voltage V1 of the internal battery 210A. Specifically, Figure 23A shows the time change of the first battery voltage V1, the first value of the first undercut voltage UC1 which will be described later, and the system lower limit voltage which will be described later. In Figure 23A, the horizontal axis represents time, and the vertical axis represents voltage.

[0243] As shown in Figure 23A, an undercut voltage UC is set for the battery voltage V1 of the internal battery 210A. Hereinafter, the undercut voltage UC set for the battery voltage V1 of the internal battery 210A may be referred to as the "first undercut voltage UC1". The first undercut voltage UC1 may be stored, for example, in the memory of the first power supply control unit 310.

[0244] The first undercut voltage UC1 is a lower limit set for the battery voltage V1 of the internal battery 210A. When the battery charge BR of the internal battery 210A decreases and the first battery voltage V1 falls below the first undercut voltage UC1, the first power control unit 310 determines that the battery charge BR of the internal battery 210A has run out and notifies the camera controller 153 of this determination. Upon receiving this notification, the camera controller 153 informs the user, for example, via the LCD monitor 163, that the battery charge BR of the internal battery 210A has run out.

[0245] More specifically, the digital camera 100 shuts down when the voltage supplied to the camera system load unit 100A falls below a certain voltage value. Hereafter, the voltage value at which the digital camera 100 shuts down may be referred to as the "system lower limit voltage."

[0246] On the other hand, as shown in Figure 23A, the battery voltage V1 of the internal battery 210A may drop sharply instantaneously. Specifically, when the load on the camera system load unit 100A increases instantaneously, and the load current supplied to the camera system load unit 100A increases instantaneously, the battery voltage V1 of the internal battery 210A drops sharply instantaneously. For example, at the start of video recording, the load current supplied to the camera system load unit 100A increases instantaneously.

[0247] Therefore, if the battery voltage V1 of the internal battery 210A drops sharply instantaneously, and the voltage supplied to the camera system load unit 100A falls below the system lower limit voltage, the digital camera 100 will shut down. To prevent the digital camera 100 from shutting down unintentionally, a lower limit value (first undercut voltage UC1) is set for the battery voltage V1 of the internal battery 210A.

[0248] Specifically, as shown in Figure 23A, the first undercut voltage UC1 is set to a value such that even if the load current instantaneously increases while the battery charge BR1 of the internal battery 210A has decreased and the first battery voltage V1 has dropped to the first undercut voltage UC1, the first battery voltage V1 will not fall below the system lower limit voltage.

[0249] As shown in Figure 23A, in Embodiment 2, a first value is preset as the first undercut voltage UC1. When the first power supply control unit 310 performs the second simultaneous power supply control, it performs a process to change the first undercut voltage UC1 from the first value to a second value that is smaller than the first value. Figure 23B is a diagram showing the second value of the first undercut voltage UC1. Specifically, Figure 23B shows the time change of the battery voltage V1 of the internal battery 210A, the second value of the first undercut voltage UC1, and the system lower limit voltage. In Figure 23B, the horizontal axis represents time, and the vertical axis represents voltage.

[0250] As explained with reference to Figures 18 to 22, when the second simultaneous power supply control is executed, battery current BJ is supplied to the camera system load unit 100A from the internal battery 210A and the external battery 220A in approximately the same proportion. Therefore, as shown in Figures 23A and 23B, when the load current instantaneously increases during the execution of the second simultaneous power supply control, the amount of fluctuation in the battery voltage V1 of the internal battery 210A is smaller than the amount of fluctuation when the battery current BJ is supplied to the camera system load unit 100A from the internal battery 210A alone. As a result, as shown in Figure 23B, even if the load current instantaneously increases while the first battery voltage V1 has dropped to the second value of the first undercut voltage UC1, the first battery voltage V1 will not fall below the system lower limit voltage. Therefore, as shown in Figure 23B, even if the first undercut voltage UC1 is changed from the first value to the second value when executing the second simultaneous power supply control, the occurrence of a malfunction in which the digital camera 100 unintentionally shuts down can be suppressed.

[0251] The second value is set, similar to the first value, so that even if the load current instantaneously increases while the first battery voltage V1 has dropped to the second value, the first battery voltage V1 will not fall below the system lower limit voltage. Specifically, when the second simultaneous power supply control is executed, the first power supply control unit 310 instructs the second power supply control unit 320 to control the second battery current BJ2 ​​so that the ratio of the first battery current BJ1 to the second battery current BJ2 ​​[BJ1:BJ2] is [1:1]. Therefore, when the load current instantaneously increases during the execution of the second simultaneous power supply control, the amount of fluctuation in the battery voltage V1 of the internal battery 210A is approximately half the amount of fluctuation when the battery current BJ is supplied to the camera system load unit 100A only from the internal battery 210A. Therefore, the second value may be set so that the voltage difference between the system lower limit voltage and the second value is half the magnitude of the voltage difference between the system lower limit voltage and the first value.

[0252] Next, we will explain the second undercut voltage UC2, which is the undercut voltage UC set for the external battery 220A.

[0253] Similar to the internal battery 210A, a second undercut voltage UC2 is set for the battery voltage V2 of the external battery 220A. In Embodiment 2, a third value is preset as the second undercut voltage UC2, similar to the first value of the first undercut voltage UC1. When the first power supply control unit 310 performs the second simultaneous power supply control, it performs the same process as the first undercut voltage UC1 to change the second undercut voltage UC2 from the third value to a fourth value that is smaller than the third value.

[0254] The third value of the second undercut voltage UC2 is typically different from the first value of the first undercut voltage UC1, but the third value of the second undercut voltage UC2 may be the same as the first value of the first undercut voltage UC1. Similarly, the fourth value of the second undercut voltage UC2 is typically different from the second value of the first undercut voltage UC1, but the fourth value of the second undercut voltage UC2 may be the same as the second value of the first undercut voltage UC1.

[0255] As described above with reference to Figures 23A and 23B, according to Embodiment 2, when the first power supply control unit 310 performs the second simultaneous power supply control, it changes the first undercut voltage UC1 from a first value to a second value and changes the second undercut voltage UC2 from a third value to a fourth value. As a result, the lower limit set for the battery voltage V of the internal battery 210A and the external battery 220A becomes smaller, and the length of time during which the digital camera 100 can be operated without replacing the internal battery 210A and the external battery 220A can be increased.

[0256] Furthermore, the first power supply control unit 310 may, in addition to executing the second simultaneous power supply control, also execute the process of changing the first undercut voltage UC1 from a first value to a second value and the process of changing the second undercut voltage UC2 from a third value to a fourth value when executing the first simultaneous power supply control. In this case, when the power supply control transitions from the first simultaneous power supply control to single power supply control, the first power supply control unit 310 executes the process of changing the first undercut voltage UC1 from a second value to a first value and the process of changing the second undercut voltage UC2 from a fourth value to a third value.

[0257] 7. Effects, etc. Embodiment 2 of the present disclosure has been described above with reference to the drawings. In Embodiment 2, the first power supply device is an internal battery 210A, which is an example of a first battery, and the second power supply device is an external battery 220A, which is an example of a second battery. A digital camera 100 or camera body 102, which is an example of an imaging device, further includes a step-up / step-down DC / DC converter 322, which is an example of a current control circuit. The step-up / step-down DC / DC converter 322 controls a second battery current BJ2, which is an example of a current supplied from the second battery to the power supply line via a second power supply switching unit. The second battery current BJ2 ​​is supplied from the external battery 220A to the first power supply line 360, which is an example of a power supply line, via a second power supply switching unit 350. The first power control unit 310 and the second power control unit 320, which are examples of control units, cause the first power switching unit 330 to select the first terminal 301 and the second power switching unit 350 to select the second terminal 302 when the battery is connected, and supply the first battery supply power BE1 and the second battery supply power BE2 to the camera system load unit 100A via the first power line 360. The first battery supply power BE1 is an example of "first power". The second battery supply power BE2 is an example of "second power". Furthermore, when the battery is connected, the first power control unit 310 and the second power control unit 320 control the step-up / step-down DC / DC converter 322 to control the second battery current BJ2 ​​so that the ratio of the first battery supply power BE1 to the second battery supply power BE2 matches the ratio of the first battery remaining charge BR1 to the second battery remaining charge BR2.

[0258] According to Embodiment 2, the camera system load unit 100A can be powered simultaneously from both the internal battery 210A and the external battery 220A, allowing the digital camera 100 or camera body 102 to operate stably even when the load current increases. Furthermore, since the second battery current BJ2 ​​is controlled so that the ratio of the first battery supply power BE1 to the second battery supply power BE2 matches the ratio of the first battery remaining charge BR1 to the second battery remaining charge BR2, the camera system load unit 100A can be powered simultaneously from both the internal battery 210A and the external battery 220A so that the first battery remaining charge BR1 and the second battery remaining charge BR2 run out at approximately the same time. Therefore, the internal battery 210A and the external battery 220A can be used efficiently to increase the length of time the digital camera 100 or camera body 102 can be used.

[0259] Furthermore, according to Embodiment 2, when both the remaining charge of the first battery BR1 and the remaining charge of the second battery BR2 fall below the remaining charge threshold, the first power control unit 310 and the second power control unit 320 control the step-up / step-down DC / DC converter 322 to control the second battery current BJ2 ​​so that the ratio of the first battery current BJ1 to the second battery current BJ2 ​​becomes a constant ratio. The remaining charge threshold is an example of a "predetermined value" set for the remaining charge of the first battery BR1 and the remaining charge of the second battery BR2. With this configuration, even after both the remaining charge of the first battery BR1 and the remaining charge of the second battery BR2 fall below the remaining charge threshold, the second battery current BJ2 ​​can be controlled so that the remaining charge of the first battery BR1 and the remaining charge of the second battery BR2 run out at approximately the same time.

[0260] Furthermore, according to Embodiment 2, a first undercut voltage UC1, which is an example of a first lower limit, is set for the first battery voltage V1, and a second undercut voltage UC2, which is an example of a second lower limit, is set for the second battery voltage V2. When the first power control unit 310 and the second power control unit 320 supply the first battery supply power BE1 and the second battery supply power BE2 to the camera system load unit 100A via the first power line 360, they change the first undercut voltage UC1 from a first value to a second value smaller than the first value, and change the second undercut voltage UC2 from a third value to a fourth value smaller than the third value. With this configuration, when the first battery supply power BE1 and the second battery supply power BE2 are supplied to the camera system load unit 100A simultaneously, the lower limits of the first battery voltage V1 and the second battery voltage V2 can be reduced, thereby increasing the length of time that the digital camera 100 or camera body 102 can be used.

[0261] Furthermore, according to Embodiment 2, the operating modes of the digital camera 100 or camera body 102 include a first operating mode and a second operating mode in which the load power is greater than that of the first operating mode. When the operating mode is the first operating mode, the first power control unit 310 and the second power control unit 320 control the first power switching unit 330 to select either the first terminal 301 or the second terminal 302, and control the second power switching unit 350 to disconnect the electrical connection between the second terminal 302 and the USB terminal 190 (an example of a third terminal) and the first power line 360 ​​via the second power switching unit 350. When the operating mode is the second operating mode, the first power control unit 310 and the second power control unit 320 cause the first power switching unit 330 to select the first terminal 301 and the second power switching unit 350 to select the second terminal 302. With this configuration, when the operating mode is the first operating mode, battery power BE can be supplied to the camera system load unit 100A without going through the step-up / step-down DC / DC converter 322, which is an example of a power control circuit. Therefore, compared to a configuration in which power is supplied to the camera system load unit 100A simultaneously from the internal battery 210A and the external battery 220A in both the first and second operating modes, the decrease in power efficiency can be suppressed.

[0262] Furthermore, according to Embodiment 2, when the operating mode is set to the first operating mode, the first power control unit 310 and the second power control unit 320 identify the battery with the larger remaining capacity BR between the internal battery 210A and the external battery 220A, and control the first power switching unit 330 to select the terminal to which the identified battery is connected between the first terminal 301 and the second terminal 302. With this configuration, power can be supplied to the camera system load unit 100A from the battery with the larger remaining capacity BR between the internal battery 210A and the external battery 220A. Therefore, the length of time that the digital camera 100 or camera body 102 can be used can be increased by efficiently utilizing the internal battery 210A and the external battery 220A.

[0263] [Other Embodiments] This disclosure is not limited to the embodiments described above, and can be implemented in various forms without departing from its essence. Furthermore, the multiple components disclosed in the above embodiments can be modified as appropriate. For example, some components from all the components shown in one embodiment may be added to the components of another embodiment, or some components from all the components shown in one embodiment may be removed from the embodiment.

[0264] The drawings schematically show each component in order to facilitate understanding, and the thickness, length, number, spacing, etc. of each component shown may differ from the actual dimensions due to the constraints of drawing creation. Furthermore, the configuration of each component shown in the above embodiments is merely an example and is not particularly limiting, and it goes without saying that various modifications are possible within the scope that does not substantially deviate from the effects of this disclosure.

[0265] For example, in the embodiment described with reference to Figures 1 to 17, the second power control unit 320 obtains a power mode that matches the current power conditions from the first power control unit 310. However, the second power control unit 320 may obtain the current operating mode of the digital camera 100 and the current power information from the first power control unit 310. In this case, the memory in the second power control unit 320 stores various table data, such as the first power condition table TA1, similar to the first power control unit 310. The second power control unit 320 controls the second power switching unit 350 based on the current operating mode of the digital camera 100 and the current power information, similar to the first power control unit 310.

[0266] Furthermore, in the embodiment described with reference to Figures 1 to 17, the first power condition table TA1 associates the first connection relationship between each of the first terminal 301, the second terminal 302, and the USB terminal 190 and the power device with power conditions 1 to 9. However, the first power condition table TA1 may also associate the first connection relationship between each of the first terminal 301, the second terminal 302, and the USB terminal 190 and the power device with power modes A to F. The same applies to the second power condition table TA2 and the third power condition table TA3. In this case, the first power mode table TA4 to the third power mode table TA6 and the fourth power mode table TA7 may be omitted.

[0267] Furthermore, in the embodiment described with reference to Figures 1 to 17, the first power mode table TA4 to the third power mode table TA6 are stored in the memory of the first power control unit 310. However, a single power mode table combining the first power mode table TA4 to the third power mode table TA6 may also be stored in the memory of the first power control unit 310.

[0268] Furthermore, in the embodiment described with reference to Figures 1 to 17, the first power mode tables TA4 to the third power mode tables TA6 include the first power mode field FD12 and the second power mode field FD13. However, the first power mode tables TA4 to the third power mode tables TA6 may also include the first switching field FD52, the second switching field FD53, the third switching field FD54, the fourth switching field FD55, and the fifth switching field FD56 of the power switching table TA8 instead of the first power mode field FD12 and the second power mode field FD13. In this case, the power switching table TA8 may be omitted.

[0269] Furthermore, the fourth power mode table TA7, as described with reference to Figure 11, may include a power condition column instead of the second power mode column FD42. In the power condition column, one of the power conditions 1 to 5, 6-1, 6-2, 7, 8-1, 8-2, 9, 11 to 19, and 21 to 29 is registered, associated with each of the power modes A to F. In this case, the first power mode tables TA4 to the third power mode tables TA6 may be omitted.

[0270] Furthermore, in the embodiment described with reference to Figures 1 to 23B, a lens-interchangeable digital camera 100 was described as an example of an imaging device, but the imaging device may also be a lens-integrated type.

[0271] Furthermore, while the embodiments described with reference to Figures 1 to 23B described a digital camera 100 as an example of an imaging device, the imaging device of this disclosure is not limited to a digital camera 100. The imaging device of this disclosure is applicable to various imaging devices that capture images of subjects. For example, the imaging device of this disclosure is applicable to movie cameras and imaging devices implemented in smartphones.

[0272] Furthermore, in the embodiment described with reference to Figures 18 to 23B, information on the remaining battery charge BR was input to the first power control unit 310 from the internal battery 210A and the external battery 220A. However, the power control unit 300 may have a circuit for detecting the first remaining battery charge BR1 and a circuit for detecting the second remaining battery charge BR2.

[0273] [Examples of embodiments] The embodiments of this disclosure are described below as examples.

[0274] [Aspect 1] An imaging device for capturing an image of a subject, comprising: a load unit for operating the imaging device; a first terminal to which a first power supply device that outputs first power is connected; a second terminal to which a second power supply device that outputs second power is detachably connected; a third terminal to which a third power supply device that outputs third power is detachably connected; a power supply line for supplying load power to the load unit; a first power switching unit that selects one of the first terminal and the second terminal and electrically connects it to the power supply line; a second power switching unit that selects one of the third terminal and the second terminal and electrically connects it to the power supply line; and a control unit that controls the first power switching unit and the second power switching unit to select one of the following: an electrical connection between the second terminal and the power supply line via the first power switching unit, or an electrical connection between the second terminal and the power supply line via the second power switching unit.

[0275] [Aspect 2] The imaging apparatus according to aspect 1, wherein the control unit, when the first power is input to the first terminal, the second power is input to the second terminal, the third power is not input to the third terminal, and the second power supplied to the power supply line is less than the load power, causes the first power switching unit to select the first terminal, and the second power switching unit to select the second terminal, thereby supplying the first power and the second power to the load unit via the power supply line.

[0276] [Aspect 3] The imaging apparatus according to aspect 1 or aspect 2, wherein the control unit causes the first power supply switching unit to select the second terminal when the first power is input to the first terminal, the second power is input to the second terminal, the third power is not input to the third terminal, and the second power supplied to the power supply line is greater than the load power.

[0277] [Aspect 4] The imaging apparatus according to any one of aspects 1 to 3, wherein the control unit, when the first power is input to the first terminal, the second power is input to the second terminal, and the third power is not input to the third terminal, and the second power supplied to the power supply line is greater than the load power, causes the first power switching unit to select the first terminal, causes the second power switching unit to select the second terminal, causes a portion of the second power to be supplied to the load unit via the power supply line, and supplies the surplus power of the second power from the first power switching unit to the first power supply device via the first terminal.

[0278] [Aspect 5] The imaging apparatus according to any one of aspects 1 to 4, wherein the third terminal is selectively connected to the third power supply device and the load device, and when the load device is connected to the third terminal, the load power increases and power is supplied from the third terminal to the load device, and the control unit, when the first power is input to the first terminal, the second power is input to the second terminal, the load device is connected to the third terminal, and the second power supplied to the power supply line is less than the load power, causes the first power switching unit to select the first terminal, and the second power switching unit to select the second terminal, and supplies the first power and the second power to the load unit via the power supply line.

[0279] [Aspect 6] The imaging apparatus according to any one of aspects 1 to 5, wherein the third terminal is selectively connected to the third power supply device and the load device, and when the load device is connected to the third terminal, the load power increases and power is supplied from the third terminal to the load device, and the control unit, in a state where the first power is input to the first terminal, the second power is input to the second terminal, the load device is connected to the third terminal, and the second power supplied to the power supply line is greater than the load power, causes the first power switching unit to select the first terminal, causes the second power switching unit to select the second terminal, supplies a portion of the second power to the load unit via the power supply line, and supplies the surplus power of the second power from the first power switching unit to the first power supply device via the first terminal.

[0280] [Aspect 7] The imaging apparatus according to any one of aspects 1 to 6, wherein the control unit causes the first power supply switching unit to select the first terminal and the second power supply switching unit to select the second terminal, and supplies the first power and the second power to the load unit via the power supply line, when the first power is input to the first terminal, the second power is input to the second terminal, and the third power is less than the second power is input to the third terminal, and the second power supplied to the power supply line is less than the load power.

[0281] [Aspect 8] The imaging apparatus according to any one of aspects 1 to 7, wherein the control unit, when the first power is input to the first terminal, the second power is input to the second terminal, and the third power, which is smaller than the second power, is input to the third terminal, and the second power supplied to the power supply line is greater than the load power, causes the first power switching unit to select the first terminal, causes the second power switching unit to select the second terminal, supplies a portion of the second power to the load unit via the power supply line, and supplies the surplus power of the second power from the first power switching unit to the first power supply device via the first terminal.

[0282] [Aspect 9] The imaging apparatus according to any one of aspects 1 to 8, wherein the control unit causes the first power supply switching unit to select the first terminal and the second power supply switching unit to select the second terminal when the first power is input to the first terminal, the second power is input to the second terminal, and the third power is not input to the third terminal.

[0283] [Aspect 10] An imaging device for capturing an image of a subject, comprising: a load unit for operating the imaging device; a first terminal to which a first power supply device that outputs first power is connected; a second terminal to which a second power supply device that outputs second power is detachably connected; a third terminal to which a third power supply device that outputs third power is detachably connected; a power supply line for supplying load power to the load unit; and a control unit that, when the first power is input to the first terminal, the second power is input to the second terminal, and the third power is not input to the third terminal, and the second power supplied to the power supply line is greater than the load power, causes a portion of the second power to be supplied to the load unit via the power supply line and supplies the surplus power of the second power to the first power supply device via the first terminal.

[0284] [Aspect 11] An imaging device for capturing an image of a subject, comprising: a load unit for operating the imaging device; a first terminal to which a first power supply device that outputs first power is connected; a second terminal to which a second power supply device that outputs second power is detachably connected; a third terminal to which a third power supply device that outputs third power is detachably connected; a power supply line for supplying load power to the load unit; a first power switching unit that selects one of the first terminal and the second terminal and electrically connects it to the power supply line; a second power switching unit that selects one of the third terminal and the second terminal and electrically connects it to the power supply line; and a control unit that causes the first power switching unit to select the first terminal and the second power switching unit to select the second terminal when the first power is input to the first terminal, the second power is input to the second terminal, and the third power is not input to the third terminal.

[0285] [Aspect 12] The imaging apparatus according to aspect 1, wherein the first power supply device is a first battery, the second power supply device is a second battery, the imaging apparatus further comprises a current control circuit that controls the current supplied from the second battery to the power supply line via the second power supply switching unit, the control unit, in a state where the first battery is connected to the first terminal and the second battery is connected to the second terminal, causes the first power supply switching unit to select the first terminal and the second power supply switching unit to select the second terminal, and supplies the first power and the second power to the load unit via the power supply line, and controls the current control circuit to control the current supplied from the second battery to the power supply line via the second power supply switching unit so that the ratio of the first power and the second power matches the ratio of the remaining capacity of the first battery, which is the remaining capacity of the first battery, and the remaining capacity of the second battery, which is the remaining capacity of the second battery.

[0286] [Aspect 13] The imaging apparatus according to aspect 12, wherein when the remaining charge of the first battery and the remaining charge of the second battery both fall below a predetermined value, the control unit controls the current control circuit to control the current supplied from the second battery to the power supply line via the second power supply switching unit so that the ratio of the current supplied from the first battery to the current supplied from the second battery becomes a constant ratio.

[0287] [Aspect 14] An imaging apparatus according to aspect 12 or aspect 13, wherein a first lower limit is set for the voltage supplied from the first battery, a second lower limit is set for the voltage supplied from the second battery, and when the control unit supplies the first power and the second power to the load unit via the power supply line, it changes the first lower limit from a first value to a second value smaller than the first value, and changes the second lower limit from a third value to a fourth value smaller than the third value.

[0288] [Aspect 15] The imaging device according to any one of aspects 12 to 14, wherein the operating modes of the imaging device include a first operating mode and a second operating mode in which the load power is greater than that of the first operating mode, the control unit controls the first power switching unit to select either the first terminal or the second terminal when the operating mode of the imaging device is the first operating mode, and controls the second power switching unit to disconnect the electrical connection between the second terminal and the third terminal via the second power switching unit and the power supply line, and when the operating mode of the imaging device is the second operating mode, the first power switching unit to select the first terminal and the second power switching unit to select the second terminal.

[0289] [Aspect 16] The imaging device according to aspect 15, wherein the control unit, when the operating mode of the imaging device is the first operating mode, identifies the battery with the larger remaining capacity among the first battery and the second battery, and controls the first power switching unit to select the terminal to which the identified battery is connected among the first terminal and the second terminal.

[0290] [Aspect 17] An imaging device for capturing an image of a subject, comprising: a load unit for operating the imaging device; a first terminal to which a first battery is connected; a second terminal to which a second battery is connected; a power supply line for supplying load power to the load unit; a current control circuit for controlling the current supplied from the second battery to the power supply line; and a control unit for controlling the current control circuit to control the current supplied from the second battery to the power supply line such that the ratio of the first power supplied from the first battery to the second power supplied from the second battery matches the ratio of the remaining capacity of the first battery to the remaining capacity of the second battery.

[0291] [Aspect 18] The imaging apparatus according to aspect 17, further comprising: a first power switching unit that electrically connects one of the first terminal and the second terminal to the power supply line; and a second power switching unit that selectively switches the electrical connection between the second terminal and the power supply line between a connected state and a disconnected state.

[0292] [Aspect 19] The imaging device according to aspect 18, wherein the operating modes of the imaging device include a first operating mode and a second operating mode in which the load power is greater than that of the first operating mode, and the control unit controls the first power switching unit to electrically connect one of the first terminal and the second terminal to the power supply line via the first power switching unit, and controls the second power switching unit to set the electrical connection between the second terminal via the second power switching unit and the power supply line to the disconnected state, and the imaging device according to aspect 18, wherein the operating mode of the imaging device is the second operating mode, and controls the first power switching unit to electrically connect the first terminal to the power supply line via the first power switching unit, and controls the second power switching unit to set the electrical connection between the second terminal via the second power switching unit and the power supply line to the connected state.

[0293] [Aspect 20] The imaging device according to aspect 19, wherein the control unit, when the operating mode of the imaging device is the first operating mode, identifies the battery with the larger remaining capacity among the first battery and the second battery, and controls the first power switching unit to electrically connect the terminal to which the identified battery is connected among the first terminal and the second terminal to the power supply line.

[0294] This disclosure is applicable to various imaging devices that capture images of subjects.

[0295] 100 Digital camera 100A Camera system load unit 102 Camera body 103 Battery grip 190 USB terminal 210A Internal battery 210B Internal coupler 220A External battery 220B External coupler 301 First terminal 302 Second terminal 310 First power control unit 320 Second power control unit 330 First power switching unit 350 Second power switching unit 360 First power line MB USB mobile battery

Claims

1. An imaging device for capturing an image of a subject, comprising: a load unit for operating the imaging device; a first terminal to which a first power supply device that outputs first power is connected; a second terminal to which a second power supply device that outputs second power is detachably connected; a third terminal to which a third power supply device that outputs third power is detachably connected; a power supply line for supplying load power to the load unit; a first power switching unit that selects one of the first terminal and the second terminal and electrically connects it to the power supply line; a second power switching unit that selects one of the third terminal and the second terminal and electrically connects it to the power supply line; and a control unit that controls the first power switching unit and the second power switching unit to select either an electrical connection between the second terminal and the power supply line via the first power switching unit, or an electrical connection between the second terminal and the power supply line via the second power switching unit.

2. The imaging apparatus according to claim 1, wherein the control unit, when the first power is input to the first terminal, the second power is input to the second terminal, the third power is not input to the third terminal, and the second power supplied to the power supply line is less than the load power, causes the first power switching unit to select the first terminal, and the second power switching unit to select the second terminal, thereby supplying the first power and the second power to the load unit via the power supply line.

3. The imaging apparatus according to claim 1, wherein the control unit, when the first power is input to the first terminal, the second power is input to the second terminal, the third power is not input to the third terminal, and the second power supplied to the power supply line is greater than the load power, causes the first power switching unit to select the second terminal and supply the second power to the load unit via the power supply line.

4. The imaging apparatus according to claim 1, wherein the control unit, when the first power is input to the first terminal, the second power is input to the second terminal, and the third power is not input to the third terminal, and the second power supplied to the power supply line is greater than the load power, causes the first power switching unit to select the first terminal, causes the second power switching unit to select the second terminal, causes a portion of the second power to be supplied to the load unit via the power supply line, and supplies the surplus power of the second power from the first power switching unit to the first power supply device via the first terminal.

5. The imaging apparatus according to claim 1, wherein the third terminal is selectively connected to the third power supply device and the load device, and when the load device is connected to the third terminal, the load power increases and power is supplied from the third terminal to the load device, and the control unit, when the first power is input to the first terminal, the second power is input to the second terminal, the load device is connected to the third terminal, and the second power supplied to the power supply line is less than the load power, causes the first power switching unit to select the first terminal, and the second power switching unit to select the second terminal, thereby supplying the first power and the second power to the load unit via the power supply line.

6. The imaging apparatus according to claim 1, wherein the third terminal is selectively connected to the third power supply device and the load device, and when the load device is connected to the third terminal, the load power increases and power is supplied from the third terminal to the load device, and the control unit, in a state where the first power is input to the first terminal, the second power is input to the second terminal, the load device is connected to the third terminal, and the second power supplied to the power supply line is greater than the load power, causes the first power switching unit to select the first terminal, causes the second power switching unit to select the second terminal, supplies a portion of the second power to the load unit via the power supply line, and supplies the surplus power of the second power from the first power switching unit to the first power supply device via the first terminal.

7. The imaging apparatus according to claim 1, wherein the control unit, when the first power is input to the first terminal, the second power is input to the second terminal, and the third power, which is less than the second power, is input to the third terminal, and the second power supplied to the power supply line is less than the load power, causes the first power switching unit to select the first terminal, and the second power switching unit to select the second terminal, thereby supplying the first power and the second power to the load unit via the power supply line.

8. The imaging apparatus according to claim 1, wherein the control unit, when the first power is input to the first terminal, the second power is input to the second terminal, and the third power, which is smaller than the second power, is input to the third terminal, and the second power supplied to the power supply line is greater than the load power, causes the first power switching unit to select the first terminal, causes the second power switching unit to select the second terminal, causes a portion of the second power to be supplied to the load unit via the power supply line, and supplies the surplus power of the second power from the first power switching unit to the first power supply device via the first terminal.

9. The imaging apparatus according to claim 1, wherein the control unit causes the first power supply switching unit to select the first terminal and the second power supply switching unit to select the second terminal when the first power is input to the first terminal, the second power is input to the second terminal, and the third power is not input to the third terminal.

10. An imaging device for capturing an image of a subject, comprising: a load unit for operating the imaging device; a first terminal to which a first power supply device that outputs first power is connected; a second terminal to which a second power supply device that outputs second power is detachably connected; a third terminal to which a third power supply device that outputs third power is detachably connected; a power supply line for supplying load power to the load unit; and a control unit that, when the first power is input to the first terminal, the second power is input to the second terminal, and the third power is not input to the third terminal, and the second power supplied to the power supply line is greater than the load power, causes a portion of the second power to be supplied to the load unit via the power supply line and supplies the surplus power of the second power to the first power supply device via the first terminal.

11. An imaging device for capturing an image of a subject, comprising: a load unit for operating the imaging device; a first terminal to which a first power supply device that outputs first power is connected; a second terminal to which a second power supply device that outputs second power is detachably connected; a third terminal to which a third power supply device that outputs third power is detachably connected; a power supply line for supplying load power to the load unit; a first power switching unit that selects one of the first terminal and the second terminal and electrically connects it to the power supply line; a second power switching unit that selects one of the third terminal and the second terminal and electrically connects it to the power supply line; and a control unit that causes the first power switching unit to select the first terminal and the second power switching unit to select the second terminal when the first power is input to the first terminal, the second power is input to the second terminal, and the third power is not input to the third terminal.

12. The imaging apparatus according to claim 1, wherein the first power supply device is a first battery, the second power supply device is a second battery, the imaging apparatus further comprises a current control circuit that controls the current supplied from the second battery to the power supply line via the second power supply switching unit, the control unit, in a state where the first battery is connected to the first terminal and the second battery is connected to the second terminal, causes the first power supply switching unit to select the first terminal and the second power supply switching unit to select the second terminal, and supplies the first power and the second power to the load unit via the power supply line, and controls the current control circuit to control the current supplied from the second battery to the power supply line via the second power supply switching unit so that the ratio of the first power and the second power matches the ratio of the remaining capacity of the first battery, which is the remaining capacity of the first battery, and the remaining capacity of the second battery, which is the remaining capacity of the second battery.

13. The imaging apparatus according to claim 12, wherein when the remaining charge of both the first battery and the second battery falls below a predetermined value, the control unit controls the current control circuit to control the current supplied from the second battery to the power supply line via the second power supply switching unit so that the ratio of the current supplied from the first battery to the current supplied from the second battery becomes a constant ratio.

14. An imaging apparatus according to claim 12 or 13, wherein a first lower limit is set for the voltage supplied from the first battery, a second lower limit is set for the voltage supplied from the second battery, and when the control unit supplies the first power and the second power to the load unit via the power supply line, it changes the first lower limit from a first value to a second value smaller than the first value, and changes the second lower limit from a third value to a fourth value smaller than the third value.

15. The imaging device according to claim 12 or 13, wherein the operating modes of the imaging device include a first operating mode and a second operating mode in which the load power is greater than that of the first operating mode, and the control unit controls the first power switching unit to select either the first terminal or the second terminal when the operating mode of the imaging device is the first operating mode, and controls the second power switching unit to disconnect the electrical connection between the second terminal and the third terminal via the second power switching unit and the power supply line, and when the operating mode of the imaging device is the second operating mode, the first power switching unit to select the first terminal and the second power switching unit to select the second terminal.

16. The imaging device according to claim 15, wherein the control unit, when the operating mode of the imaging device is the first operating mode, identifies the battery with the larger remaining capacity among the first battery and the second battery, and controls the first power switching unit to select the terminal to which the identified battery is connected among the first terminal and the second terminal.

17. An imaging device for capturing an image of a subject, comprising: a load unit for operating the imaging device; a first terminal to which a first battery is connected; a second terminal to which a second battery is connected; a power supply line for supplying load power to the load unit; a current control circuit for controlling the current supplied from the second battery to the power supply line; and a control unit for controlling the current control circuit to control the current supplied from the second battery to the power supply line such that the ratio of the first power supplied from the first battery to the second power supplied from the second battery matches the ratio of the remaining capacity of the first battery to the remaining capacity of the second battery.

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