Electronic device, system, electronic device control method, program, and storage medium

Abstract

To supply a more appropriate voltage from an accessory to an electronic apparatus capable of requesting the voltage of power received from the accessory by preventing an increase in the starting time of the electronic apparatus.SOLUTION: The electronic apparatus includes a communication unit configured to request a predetermined accessory to supply power of a first voltage when a signal level of a communication line is a first level at a time of activation, and not to request the accessory to supply the power of the first voltage when the signal level is a second level, a first setting unit configured to set the signal level to the second level when the communication unit requests the accessory to supply the power of the first voltage, and a first control unit configured to perform control to maintain the signal level at the time of stop of a power supply after the power supply is stopped. When it is detected that the signal level is changed from the second level to the first level after the power supply is stopped, the communication means requests the power of the first voltage to the predetermined accessory.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an electronic device, a system, a control method for an electronic device, a program, and a storage medium. [Background technology]

[0002] Power accessories that supply power to imaging devices are known. The power accessories have a shape that allows them to be attached to the battery compartment of the imaging device. By attaching the power accessory to the battery compartment instead of a battery, the imaging device can be supplied with power from a household power source or the like. In addition, by standardizing the shape of the battery compartment across different models, batteries and power accessories can be used in common across different models.

[0003] Furthermore, as imaging devices become more multifunctional, their power consumption is increasing. This increase in power consumption necessitates power accessories that can supply greater power. It would be effective to enable the use of power accessories that can supply such large amounts of power with conventional imaging devices that have the same battery compartment shape but do not consume much power. To achieve this, it is desirable for the power accessory to be able to supply power appropriate to the imaging device to which it is attached. For example, it would be sufficient for the power accessory to output an appropriate voltage or current depending on the imaging device connected to it.

[0004] A power supply standard called USB Power Delivery (USB PD) compatible with USB Type-C terminals has been known. Imaging devices and various other devices compatible with USB PD are becoming widespread. According to the USB PD standard, a power supply device can supply multiple voltages and currents. A power receiving device compatible with the USB PD standard can request a desired voltage from among multiple voltages that the power supply device can output. Therefore, it is effective for a power accessory to have the functionality of a power receiving device compatible with USB PD. Patent Documents 1 and 2 describe configurations including a power supply device and a power receiving device. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-92722 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-309778 Summary of the Invention [Problem to be solved by the invention]

[0006] By functioning as a USB PD-compliant power receiving device, a power accessory can receive different voltages from a power supply device depending on the situation. Therefore, the power accessory can request a voltage appropriate for the imaging device connected to the power accessory and supply it to the imaging device. On the other hand, with USB PD, when a power supply device and a power receiving device are connected, power negotiation is performed, and the power receiving device requests the desired voltage from the power supply device, after which power is supplied from the power supply device. When an imaging device receives power from a USB PD-compatible power accessory, upon startup of the imaging device, the power accessory must perform power negotiation with the USB PD power supply device and then wait for the requested voltage to be output from the power supply device. Thus, multiple procedures are required before the desired voltage is supplied from the power accessory to the imaging device. It is desirable for the imaging device to perform startup processing after the required power is supplied from the power accessory to the imaging device. This poses a problem of increased startup time for the imaging device.

[0007] Furthermore, when the power accessory and the power supply device are disconnected and then reconnected, it is also necessary for the power accessory to supply a voltage suitable for the imaging device to the imaging device.

[0008] Therefore, the present invention aims to provide a technology that prevents an increase in the startup time of an electronic device that can request a power voltage from an accessory, and enables a more appropriate voltage to be supplied from the accessory to the electronic device. [Means for solving the problem]

[0009] One aspect of the present invention is a method for producing a medicament for the treatment of a pulmonary arthritis. An electronic device to which a predetermined accessory that supplies power is removably connected, a communication means for communicating with the predetermined accessory via a communication line, the communication means performing predetermined communication processing to request the predetermined accessory to supply power of a first voltage when the signal level of the communication line is at a first level, and not to request the predetermined accessory to supply power of the first voltage when the signal level of the communication line is at a second level when the electronic device is started up; a first setting means for setting a signal level of the communication line to the second level when the communication means requests the predetermined accessory to supply power of the first voltage; a first control means for controlling the signal level of the communication line to be maintained at the time when the power supply of the electronic device was stopped after the power supply of the electronic device was stopped; a detection means for detecting a change in the signal level of the communication line from the second level to the first level when the signal level of the communication line is set to the second level; and When the detection means detects that the signal level of the communication line has changed from the second level to the first level after the power supply of the electronic device has been stopped, the communication means requests power of the first voltage from the predetermined accessory. The electronic device is characterized by the above.

[0010] One aspect of the present invention is a method for producing a medicament for the treatment of a pulmonary arthritis. A method for controlling an electronic device to which a predetermined accessory that supplies power is removably connected, comprising: a communication step of performing a predetermined communication process in which, when the electronic device is started up, the electronic device communicates with the predetermined accessory via a communication line, if the signal level of the communication line is at a first level, the predetermined accessory is requested to supply power of a first voltage, and if the signal level of the communication line is at a second level, the predetermined accessory is not requested to supply power of the first voltage; a first setting step of setting a signal level of the communication line to the second level when the predetermined accessory is requested to supply power of the first voltage in the communication step; a first control step of performing control so as to maintain the signal level of the communication line at the time when the power supply of the electronic device was stopped after the power supply of the electronic device was stopped; a detecting step capable of detecting, when the signal level of the communication line is set to the second level, that the signal level of the communication line has changed from the second level to the first level; and When it is detected in the detecting step that the signal level of the communication line has changed from the second level to the first level after the power supply of the electronic device has been stopped, the communicating step requests the predetermined accessory for power of the first voltage. The present invention relates to a method for controlling an electronic device. [Effects of the Invention]

[0011] According to the present invention, in an electronic device that can request a voltage for power received from an accessory, an increase in the startup time of the electronic device can be prevented, and a more appropriate voltage can be supplied from the accessory to the electronic device. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is an external view of a digital camera according to a first embodiment. [Figure 2] 1 is a diagram illustrating the configuration of a digital camera according to a first embodiment. [Figure 3]1 is a diagram illustrating the configuration of an AC adapter according to a first embodiment. [Figure 4] 4 is a flowchart of processing at the time of startup of the digital camera according to the first embodiment. [Figure 5] 10 is a flowchart of a process at the time of shutting down the digital camera according to the first embodiment. [Figure 6] 4 is a flowchart of a process of the AC adapter according to the first embodiment. [Figure 7] 10 is a flowchart of a process performed when a momentary power outage occurs in the digital camera according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0014] <Embodiment 1> In the first embodiment, power negotiation between a "digital camera" and an "AC adapter compatible with USB PD" will be described.

[0015] FIG. 1 shows an external view of a digital camera 100 as an example of an applicable device (electronic device). An AC adapter 203 is removably connected to the digital camera 100. The display unit 28 is a display unit that displays images and various information. The shutter button 61 is an operation unit for issuing a shooting instruction. The mode selector switch 60 is an operation unit for switching between various modes. The connection cable 111 is a cable for connecting to an external device (such as a personal computer or a printer). The connector 112 is a connector between the connection cable 111 and the digital camera 100. The operation unit 70 includes operation members (such as various switches, buttons, or a touch panel) that accept various operations from the user. The controller wheel 73 is a rotatable operation member included in the operation unit 70. The power switch 72 is a push button for switching between power on and power off.

[0016] The recording medium 200 is a recording medium such as a memory card or a hard disk. The AC adapter 203 is a predetermined power accessory that supplies power to the digital camera 100. The AC adapter 203 has a USB connector 204. The USB connector 204 is connected to a PD power adapter 205, which is a power supply device that supports USB Power Delivery (USB PD). The PD power adapter 205 is a power supply device that is connected to a household power outlet via a plug 206. When a USB PD-compatible power receiving device is connected to the PD power adapter 205 via a USB Type-C cable, the PD power adapter 205 supplies power in accordance with the USB PD standard. In FIG. 1 , the AC adapter 203, which is a USB PD-compatible power receiving device, is connected to the PD power adapter 205, and the PD power adapter 205 supplies power to the AC adapter 203 in accordance with the USB PD standard. In this way, a stable power supply is provided to the digital camera 100 from the PD power adapter 205 via the AC adapter 203.

[0017] The slot 201 is a slot for storing the recording medium 200 and the AC adapter 203. The slot 201 has a battery chamber (not shown), and the battery 300 is inserted into the digital camera 10. When the digital camera 100 is used as a power source for the digital camera 100, a battery 300 is attached to the battery compartment. When the AC adapter 203 is used as a power source for the digital camera 100, the AC adapter 203 is attached to the battery compartment instead of the battery 300. The battery 300 and the AC adapter 203 have the same shape. A user can easily attach either the battery 300 or the AC adapter 203 to the battery compartment and easily remove them from the battery compartment. The battery compartment is also provided with terminals for the digital camera 100 to communicate with the battery 300 or the AC adapter 203 and for receiving power. By connecting the terminals on the battery 300 or the AC adapter 203 to these terminals, power supply from and communication with the battery 300 or the AC adapter 203 becomes possible. The recording medium 200 stored in the slot 201 can communicate with the digital camera 100, and therefore can record and play back images acquired from the digital camera 100. The lid 202 is a lid for the slot 201. FIG. 1 shows a state in which the cover 202 is opened and part of the recording medium 200 and part of the AC adapter 203 are removed and exposed from the slot 201.

[0018] FIG. 2 is a block diagram showing an example configuration of a digital camera 100 according to the first embodiment. The photographing lens 103 is a lens group including a zoom lens and a focus lens. The shutter 101 has an aperture function. The imaging unit 22 is an imaging element (image sensor) formed of a CCD, CMOS element, or the like that converts an optical image into an electrical signal. The A / D converter 23 converts an analog signal into a digital signal. The A / D converter 23 is used to convert the analog signal output from the imaging unit 22 into a digital signal. The barrier 102 covers the imaging system (including the photographing lens 103, shutter 101, and imaging unit 22) to prevent the imaging system from becoming dirty or being damaged.

[0019] The image processing unit 24 performs image processing (predetermined pixel interpolation, resizing such as reduction, and color conversion processing) on ​​data from the A / D converter 23 or data from the memory control unit 15. The image processing unit 24 also performs predetermined arithmetic processing using the captured image data. Based on the arithmetic results obtained by the image processing unit 24, the system control unit 50 performs exposure control and distance measurement control. This results in TTL (through-the-lens) AF (autofocus) processing, AE (autoexposure) processing, and EF (flash pre-flash) processing. The image processing unit 24 also performs predetermined arithmetic processing using the captured image data. Based on the arithmetic results obtained, the image processing unit 24 performs TTL AWB (auto white balance) processing.

[0020] The output data from the A / D converter 23 is written directly into the memory 32 via the image processing unit 24 and the memory control unit 15, or via only the memory control unit 15. The memory 32 stores image data obtained by the imaging unit 22 and converted into digital data by the A / D converter 23. The memory 32 stores image data to be displayed on the display unit 28. The memory 32 has a storage capacity sufficient to store a predetermined number of still images and a predetermined period of moving images and audio.

[0021] The memory 32 also serves as a memory (video memory) for image display. The D / A converter 13 converts the image display data stored in the memory 32 into an analog signal and supplies it to the display unit 28. The display image data written in the memory 32 in this way is sent to the display unit 28 via the D / A converter 13. The display unit 28 displays an image on a display device such as an LCD in accordance with the analog signal from the D / A converter 13. The A / D converter 23 converts the digital signal once, and the digital signal is stored in the memory 32. The digital signal is converted to analog in the D / A converter 13, and the analog-converted signal is transferred sequentially to the display unit 28. This allows the display unit 28 to function as an electronic viewfinder and display a through image (live view display (LV display)). Hereinafter, the image displayed in live view will be referred to as The resulting image is called an LV image.

[0022] The nonvolatile memory 56 is an electrically erasable and recordable recording medium. For example, an EEPROM or the like is used as the nonvolatile memory 56. Constants, programs, etc. for the operation of the system control unit 50 are stored in the nonvolatile memory 56. The programs referred to here are computer programs for executing various flowcharts described later in the first embodiment.

[0023] The system control unit 50 is a control unit made up of at least one processor and / or at least one circuit. The system control unit 50 controls the entire digital camera 100. The system control unit 50 executes programs recorded in the nonvolatile memory 56 described above to realize each process described in the first embodiment, which will be described later. The system memory 52 may be, for example, a RAM. Constants and variables for the operation of the system control unit 50, programs read from the nonvolatile memory 56, and the like are loaded into the system memory 52. ​​The system control unit 50 also performs display control by controlling the memory 32, the D / A converter 13, the display unit 28, and the like.

[0024] The system timer 53 is a timekeeping unit that measures the time used for various controls and the time of a built-in clock.

[0025] The mode selector switch 60, shutter button 61, and operation unit 70 are operation members for inputting various operational instructions to the system control unit 50. The mode selector switch 60 switches the operation mode of the system control unit 50 between still image recording mode, video shooting mode, playback mode, etc. Modes included in the still image recording mode include auto shooting mode, auto scene determination mode, manual mode, aperture priority mode (Av mode), shutter speed priority mode (Tv mode), and program AE mode. Modes included in the still image recording mode include various scene modes and custom modes that provide shooting settings for specific shooting scenes. Using the mode selector switch 60, the user can directly switch to one of these modes. Alternatively, after switching to a list screen of shooting modes using the mode selector switch 60, the user may select one of the displayed modes and then switch using other operation members. Similarly, the video shooting mode may also include multiple modes.

[0026] The first shutter switch 62 generates a first shutter switch signal SW1 when it is turned on by half-pressing (a shooting preparation instruction) during operation of the shutter button 61 provided on the digital camera 100. The generation of the first shutter switch signal SW1 starts operations such as AF (autofocus) processing, AE (auto exposure) processing, AWB (auto white balance) processing, and EF (pre-flash) processing.

[0027] The second shutter switch 64 generates a second shutter switch signal SW2 when the shutter button 61 is fully pressed (photographing instruction) and turned on. When the second shutter switch signal SW2 is generated, the system control unit 50 starts a series of operations for photographing processing (processing from reading out a signal from the imaging unit 22 to writing image data to the recording medium 200).

[0028] Each operating member of the operating unit 70 functions as a button for various functions. To each operating member of the operating unit 70, a function is assigned as appropriate for each situation by selecting and operating various function icons displayed on the display unit 28. Examples of the function buttons include an end button, a back button, an image forward button, a jump button, a narrow down button, an attribute change button, etc. For example, when the menu button is pressed, a menu screen that can be set for various purposes is displayed on the display unit 28. The user can intuitively make various settings using the menu screen displayed on the display unit 28, the four-way buttons (up, down, left, right) and the SET button.

[0029] The controller wheel 73 is a rotatable operation member included in the operation unit 70. The controller wheel 73 is used, together with the directional buttons, to indicate a selection item. When the controller wheel 73 is rotated, an electrical pulse signal is generated according to the amount of rotation, and the system control unit 50 controls each unit of the digital camera 100 based on this pulse signal. This pulse signal can determine the angle at which the controller wheel 73 is rotated and the number of rotations made. The controller wheel 73 may be any operation member that can detect a rotation operation. For example, the controller wheel 73 may be a dial operation member that rotates itself in response to a user's rotation operation to generate a pulse signal. Alternatively, the controller wheel 73 may be an operation member made of a touch sensor that does not rotate itself but detects the rotation of the user's finger on the controller wheel 73 (a so-called touch wheel).

[0030] The power supply control unit 80 is composed of a battery detection circuit, a DC-DC converter, a switch circuit (a circuit that switches the block to which electricity is applied), etc. The power supply control unit 80 detects whether a battery is installed, the battery type, and the remaining battery power. Furthermore, the power supply control unit 80 controls the DC-DC converter based on the detection results and instructions from the system control unit 50, and supplies the required voltage to each unit, including the recording medium 200, for the required period of time.

[0031] The power supply unit 30 is a battery 300 or an AC adapter 203. The battery 300 includes, for example, a primary battery (such as an alkaline battery or a lithium battery) or a secondary battery (such as a NiCd battery, a NiMH battery, or a Li battery). In the first embodiment, a case will be described in which the AC adapter 203 is inserted into the slot 201 to form the power supply unit 30. The power supply unit 30 may be included in the digital camera 100, but the first embodiment will be described assuming that it is not included in the digital camera 100. For this reason, the first embodiment is an embodiment that describes a system that includes the digital camera 100, the power supply unit 30 (battery 300 or AC adapter 203), a PD power adapter 205, etc.

[0032] The recording medium I / F 18 is an interface with a recording medium 200, such as a memory card or a hard disk. The recording medium 200 is a recording medium such as a memory card for recording captured images. The recording medium 200 includes a semiconductor memory, an optical disk, a magnetic disk, or the like.

[0033] The communication unit 54 is connected wirelessly or via a wired cable and transmits and receives video signals, audio signals, and the like. The communication unit 54 can also be connected to a wireless LAN (Local Area Network) or the Internet. The communication unit 54 can also communicate with external devices via Bluetooth (registered trademark), Bluetooth Low Energy, and the like. The communication unit 54 can transmit images (including live images) captured by the imaging unit 22 and images recorded on the recording medium 200. The communication unit 54 can also receive image data and various other information from external devices.

[0034] The attitude detection unit 55 detects the attitude of the digital camera 100 with respect to the direction of gravity. Based on the attitude detected by the attitude detection unit 55, it is possible to determine whether the image captured by the imaging unit 22 was captured with the digital camera 100 held horizontally or vertically. The system control unit 50 can add orientation information according to the attitude detected by the attitude detection unit 55 to the image file of the image captured by the imaging unit 22, or rotate and record the image. The attitude detection unit 55 can use an acceleration sensor, a gyro sensor, or the like. The attitude detection unit 55 can use an acceleration sensor, a gyro sensor, or the like. It is also possible to detect the movement of the digital camera 100 (panning, tilting, lifting, whether it is stationary or not, etc.).

[0035] FIG. 3 is a block diagram showing an example of the configuration of the AC adapter 203 according to the first embodiment.

[0036] The terminal 250 is an electrical contact point with the digital camera 100. The terminal 250 includes a power terminal and a communication terminal.

[0037] The control unit 251 controls each component of the AC adapter 203 .

[0038] When the PD power adapter 205 is connected to the USB connector 204, the PD controller 252 communicates with the PD power adapter 205. The PD controller 252 is also connected to the control unit 251. The registers of the PD controller 252 can be changed by the control unit 251.

[0039] The switched capacitor 253 is a switched capacitor type DC-DC converter. The switched capacitor 253 converts an input voltage into an integer fraction and outputs (generates) an output voltage. In the first embodiment, the switched capacitor 253 converts the input voltage into 1 / 2 (half) and outputs it.

[0040] The discharge circuit 254 discharges the charge in the capacitor 255 under the control of the control unit 251 .

[0041] Capacitor 255 is a high-capacity capacitor that can secure the power used for performing shutdown processing by digital camera 100. Capacitor 255 is connected to the output of switched capacitor 253, and therefore holds the output voltage (the voltage output from AC adapter 203 to digital camera 100).

[0042] The FET 256 is a field effect transistor that controls the power output of the AC adapter 203 under the control of the control unit 251.

[0043] The communication unit 257 enables communication between the power supply control unit 80 and the control unit 251 .

[0044] The device detection unit 258 detects whether or not the AC adapter 203 is inserted in the slot 201 of the digital camera 100 .

[0045] The USB connection detection unit 259 detects whether or not the PD power adapter 205 is connected to the USB connector 204. The output voltage detection unit 260 A / D converts the signal on the output voltage wiring 262 to detect the output voltage.

[0046] The input voltage wiring 261 connects the input voltage from the PD power adapter 205 connected via the USB connector 204 to the control unit 251. The output voltage wiring 262 connects the output of the switched capacitor 253 and the control unit 251.

[0047] Communication line 263 is connected to the communication terminal of terminal 250, thereby enabling communication between power supply control unit 80 and control unit 251 via communication unit 257. "Communication line 263" and "the communication line between power supply control unit 80 and power supply unit 30" have the same signal level when digital camera 100 and AC adapter 203 are connected to each other.

[0048] The non-volatile memory 264 holds the operating parameters.

[0049] Here, the operation of the PD power adapter 205 will be described. When the USB connector 204 is connected to the PD power adapter 205, the PD power adapter 205 first supplies 5V as an input voltage, starting up each component of the AC adapter 203. Next, the PD controller 252 negotiates power with the PD power adapter 205 via the USB connector 204 and requests the PD power adapter 205 to supply 15V / 3A of power. When 15V power is supplied from the PD power adapter 205, the input voltage is halved by the switched capacitor 253, and 7.5V, half of 15V, is output from the terminal 250 as the output voltage.

[0050] As a result of this processing, in the initial state immediately after AC adapter 203 is turned on, a voltage of 7.5V (initial voltage) is output from terminal 250. As will be described later, even if a command requesting an output voltage of 10V is not transmitted from digital camera 100, AC adapter 203 outputs an output voltage of 7.5V. Control unit 251 can also control PD controller 252 to perform power negotiation requesting a power supply of 20V / 3A. In this case, the input voltage is also halved by switched capacitor 253, so an output voltage of 10V is output from terminal 250.

[0051] The digital camera 100 according to the first embodiment is designed to operate at a voltage of 10 V. Another model of digital camera connectable to the AC adapter 203 may be designed to operate at a voltage of 7.5 V. In the first embodiment, a case is described in which the AC adapter 203 is capable of outputting voltages of 10 V and 7.5 V, but the output voltage is not limited to these. For example, if the AC adapter 203 is connectable to multiple models of digital cameras, the initial voltage may be the lowest voltage required by these multiple models of digital cameras. This is to prevent the digital camera 100 from being damaged by a high-voltage power supply to the digital camera 100.

[0052] With reference to the flowchart in Fig. 4, the processing executed by the system control unit 50 when the digital camera 100 (electronic device) is started up will be described. The processing in Fig. 4 is performed by the CPU of the system control unit 50 executing a program stored in the non-volatile memory 56. Note that, hereinafter, communication between the digital camera 100 and the power supply unit 30 (battery 300, AC adapter 203) is controlled by the communication unit 54 in the digital camera 100. Furthermore, "starting up" here includes processing that is started up when the user instructs the digital camera 100 to turn on the power by operating the power switch 72 while the digital camera 100 is in a power-off state. Furthermore, "starting up" here includes processing that is started up when the digital camera 100 returns from an auto-power-off state.

[0053] Furthermore, startup here includes the process of starting up when, after a state in which the AC adapter 203 was not connected to the digital camera 100, the digital camera 100 and the AC adapter 203 are connected and power supply to the digital camera 100 starts via a household power source and the PD power adapter 205. Also, startup here includes the process of starting up when, after a state in which the AC adapter 203 was connected to the digital camera 100 but the PD power adapter 205 was not connected to the AC adapter 203, the AC adapter 203 and the PD power adapter 205 are connected and power supply to the digital camera 100 starts. Also, startup here includes the process of starting up when, after a state in which the AC adapter 203 was connected to the digital camera 100 and the PD power adapter 205 was connected to the AC adapter 203 but the PD power adapter 205 was not connected to a household power source, the PD power adapter 205 was connected to a household power source and power supply to the digital camera 100 starts. At the start of the processing of the flowchart in FIG. 4, "L edge interrupts that use the communication line between the power supply control unit 80 and the power supply unit 30 as a signal line for external interrupts" are disabled.

[0054] In step S300, the system control unit 50 reads the signal level of the communication line connecting the power supply unit 30 and the power supply control unit 80. Here, if the communication line is set to I(pu), which enables the internal pull-up setting, communication is not taking place between the system control unit 50 and the control unit 251 in the AC adapter 203. Therefore, in this case, the H level is read as the signal level of the communication line. If it is determined that the signal level of the communication line is H level, the process proceeds to step S301. If it is determined that the signal level of the communication line is L level, the process proceeds to step S302.

[0055] In step S301, the system control unit 50 sets a negotiation execution flag (hereinafter referred to as an "execution flag"), which is a flag indicating whether the power supply unit 30 performs negotiation, to Off. Then, the system control unit 50 stores the execution flag set to Off (the execution flag indicating that negotiation will not be performed) in the RAM of the system memory 52.

[0056] In step S302, the system control unit 50 sets the execution flag to On, and then stores the execution flag (an execution flag indicating that negotiation is to be performed) in the RAM of the system memory 52.

[0057] In step S303, the system control unit 50 disables the pull-up operation of the communication line between the power supply control unit 80 and the power supply unit 30, thereby enabling the power supply control unit 80 and the power supply unit 30 to communicate with each other. Note that the pull-up may be either an internal or external pull-up, but in the first embodiment, an internal pull-up is used.

[0058] In step S304, the system control unit 50 controls the power supply control unit 80 to send a command (hereinafter referred to as a "type determination command") to the power supply unit 30 to instruct it to determine the type (battery type) of the power supply unit 30 (the power supply unit 30 inserted in the slot 201). The digital camera 100 can be connected to either a battery 300 or an AC adapter 203. Both the battery 300 and the AC adapter 203 can communicate with the power supply control unit 80. Therefore, the power supply control unit 80 can determine the battery type by communicating with the power supply unit 30.

[0059] When a command is sent from digital camera 100 in step S304, system controller 50 repeatedly switches the signal level of the communication line between power controller 80 and power unit 30 between L level and H level. After sending the command, system controller 50 returns the current signal level to the signal level before sending the command. This type of processing is also performed in steps S312 and S313, which will be described later.

[0060] In step S305, the system control unit 50 acquires information about the battery type from the power supply unit 30. The system control unit 50 stores a variable Type indicating the battery type in the RAM of the system memory 52.

[0061] In step S306, the system control unit 50 references the variable Type to determine whether the power supply unit 30 (the power supply unit 30 attached to the slot 201) is an AC adapter 203 (power accessory) or a battery 300. If it is determined that the power supply unit 30 is a battery 300, the process proceeds to step S307. If it is determined that the power supply unit 30 is an AC adapter 203, the process proceeds to step S309.

[0062] In step S307, the system control unit 50 attempts to authenticate the battery 300 and determines whether or not the battery 300 is an authenticated battery. If it is determined that the battery 300 is not an authenticated battery, the system control unit 50 displays a guidance message informing the user that the battery 300 is not an authenticated battery. The display unit 28 displays the message and asks the user whether or not to use the battery.

[0063] In step S308, the system control unit 50 executes power startup processing for the digital camera 100. Specifically, the system control unit 50 controls the power control unit 80 to supply power to each block of the digital camera 100. If the power supply unit 30 is a battery 300, the startup processing is executed using power from the battery 300. This enables the system control unit 50 to operate functions such as capturing or playing images (still images or videos). When the processing of step S308 ends, the startup processing of the digital camera 100 is completed. Therefore, the time required from the start of the processing of this flowchart until the processing of step S308 ends is the startup time of the digital camera 100.

[0064] In step S309, the system control unit 50 determines whether the AC adapter 203 supports USB PD based on the variable Type held in step S305. If it is determined that the AC adapter 203 supports USB PD, the process proceeds to step S310. If it is determined that the AC adapter 203 does not support USB PD, the process proceeds to step S308. Here, if the AC adapter does not support USB PD, the output voltage cannot be changed, and a predetermined voltage, for example, is supplied from the AC adapter. The predetermined voltage does not have to be 10 V, but is a voltage that allows the digital camera 100 to operate.

[0065] In step S310, the system control unit 50 determines the voltage (hereinafter referred to as the "requested voltage") required by the digital camera 100 executing the program for the processing in FIG. 4, based on the information read from the nonvolatile memory 56. The required voltage of the digital camera 100 according to the first embodiment is 10V. Therefore, the required voltage is determined to be 10V here, and an output voltage of 10V must be requested from the AC adapter 203, so the process proceeds to step S311. Depending on the model of digital camera, the required voltage may be 7.5V. In that case, power at the initial voltage of 7.5V has already been supplied from the AC adapter 203, and no negotiation is necessary, so the process proceeds to step S308.

[0066] In step S311, the system control unit 50 determines the setting of the execution flag held in steps S301 and S302. If it is determined that the execution flag is set to On (the signal level is L level at startup), the process proceeds to step S312. If it is determined that the execution flag is set to Off (the signal level is H level at startup), the process proceeds to step S308.

[0067] In step S312, the system control unit 50 transmits a command (hereinafter referred to as a "10V command") to the AC adapter 203 to instruct it to switch the output voltage from the AC adapter 203 to 10 V. This causes the system control unit 50 to request an output voltage of 10 V from the AC adapter 203. In this way, if the system control unit 50 determines in step S311 that the execution flag is set to On (the signal level of the communication line when the digital camera 100 is started is L level), it transmits the 10V command. This causes the system control unit 50 to request the AC adapter 203 to supply 10 V of power to the digital camera 100.

[0068] On the other hand, if the system control unit 50 determines in step S311 that the execution flag is set to Off (the signal level of the communication line when the digital camera 100 is started is at H level), it does not send a 10V command. In other words, in such a case, the system control unit 50 does not request the AC adapter 203 to supply 10V power to the digital camera 100. Therefore, the digital camera 100 does not receive the power of the voltage it most recently (past) requested from the AC adapter 203 (the voltage most recently supplied by the AC adapter The power (voltage power that was supplied to the digital camera 100 from the AC adapter 203) is supplied from the AC adapter 203.

[0069] In step S313, the system control unit 50 transmits a reply command to the AC adapter 203. The reply command is a command requesting the AC adapter 203 to reply with the output voltage of the power output from the AC adapter 203 to the digital camera 100. The system control unit 50 also acquires output voltage information from the AC adapter 203.

[0070] In response to the commands transmitted in steps S312 and S313, the control unit 251 of the AC adapter 203 performs the processes from step S410 onward in the flowchart of FIG. 6, which will be described later.

[0071] In step S314, the system control unit 50 reads the information about the output voltage of the AC adapter 203 obtained in step S313. Then, the system control unit 50 determines whether the output voltage is 10 V. If it is determined that the output voltage is 10 V, the process proceeds to step S315. If it is determined that the output voltage is not 10 V, the processes of steps S313 and S314 are repeated until it is determined in step S314 that the output voltage is 10 V.

[0072] In step S315, the system control unit 50 enables the built-in pull-up of the communication line between the power supply control unit 80 and the AC adapter 203. As a result, the signal level of the communication line between the power supply control unit 80 and the power supply unit 30 is set (maintained) at the H level. Thereafter, when communication with the AC adapter 203 is necessary, the system control unit 50 disables the built-in pull-up as in step S303, and after communication is completed, it re-enables the built-in pull-up as in step S315.

[0073] In step S316, the system control unit 50 sets an "L edge interrupt" that uses the communication line between the power supply control unit 80 and the power supply unit 30 as a signal line for issuing an external interrupt. By setting the L edge interrupt, when the signal level of the communication line changes from H level to L level, the system control unit 50 can immediately detect the change. The process performed when a change in the signal level from H level to L level is detected will be described later with reference to the flowchart in FIG. 7.

[0074] When AC adapter 203 is removed from slot 201, power supply to digital camera 100 is cut off, so the communication line between power supply control unit 80 and power supply unit 30 cannot be maintained at H level and the signal level becomes L level. Therefore, after battery 300 attached to slot 201 is replaced with AC adapter 203, the signal level of the communication line is determined to be L level at the first power-on startup in step S301.

[0075] 5 is a flowchart of the program executed by the system control unit 50, illustrating the processing performed when the digital camera 100 is shut down (when startup is completed). The shutdown processing in FIG. 5 includes processing performed when the user operates the power switch 72 to instruct the digital camera 100 to power off. The shutdown processing in FIG. 5 also includes processing performed when the digital camera 100 transitions to an auto power off state. If no operation is performed on the digital camera 100 for a certain period of time, the system control unit 50 transitions the digital camera 100 to the auto power off state. Furthermore, if any operation is performed on the digital camera 100 while the digital camera 100 is in the auto power off state, the system control unit 50 performs the startup processing in FIG. 4.

[0076] In step S350, the system control unit 50 performs the power-off process for the digital camera 100. Specifically, the system control unit 50 controls the power supply control unit 80 to stop the supply of power to each block of the digital camera 100. As a result, the system control unit 50 disables functions such as taking or playing images (still images or videos).

[0077] In step S351, the system control unit 50 controls the power supply control unit 80 in the same manner as in step S304, and communicates with the power supply unit 30 to obtain information on the battery type.

[0078] In step S352, the system control unit 50 determines, based on the battery type information, whether the power supply unit 30 (the power supply unit 30 inserted in the slot 201) is a battery 300 or an AC adapter 203. If it is determined that the power supply unit 30 is a battery 300, the process proceeds to step S353. If it is determined that the power supply unit 30 is an AC adapter 203, the process proceeds to step S355.

[0079] In step S353, the system control unit 50 controls the power supply control unit 80 to instruct the power supply unit 30 to transition to the sleep state. In this case, the power supply unit 30 transitions the controller in the battery 300 to a low power consumption mode, and sets it to reduce the power consumption of the battery 300.

[0080] In step S354, the system control unit 50 sets the communication line between the power supply control unit 80 and the power supply unit 30 to output an L level.

[0081] In step S355, the system control unit 50 maintains the L edge interrupt enabled in step S316 so that the communication line between the power control unit 80 and the power supply unit 30 is used as a signal line for external interrupts. The system control unit 50 also controls the signal level of the communication line between the power control unit 80 and the power supply unit 30 to be maintained at the current level even after the power to the digital camera 100 is turned off. For example, if the signal level of the communication line was H level when a power-off command was issued, the H level is maintained even in the power-off state.

[0082] 6, the processing executed by control unit 251 in AC adapter 203 will be described. When USB connector 204 of AC adapter 203 is connected to PD power adapter 205, power is supplied from PD power adapter 205. By being connected to PD power adapter 205, control unit 251 is started up by power from PD power adapter 205.

[0083] In step S400, the control unit 251 controls the PD controller 252 to start communication with the PD power adapter 205 and perform power negotiation. The control unit 251 then requests the PD power adapter 205 to supply power at a voltage of 15V. The PD controller 252 requests 15V from the PD power adapter 205, and the PD power adapter 205 outputs a voltage of 15V.

[0084] In step S401, control unit 251 controls output voltage detection unit 260 to read the output voltage from AC adapter 203 to digital camera 100. As described above, the input voltage of 15V from PD power adapter 205 is converted to half by switched capacitor 253, resulting in an output voltage of 7.5V.

[0085] In step S402, the control unit 251 determines whether the output voltage obtained in step S401 is 7.5 V. If it is determined that the output voltage is 7.5 V, the process proceeds to step S403. If it is determined that the output voltage is not 7.5 V, the processes of steps S401 and S402 are repeated.

[0086] In step S403, the control unit 251 turns on the FET 256. As a result, the power supply control unit 80 of the digital camera 100 detects that the power required to start up the digital camera 100 is being supplied, and the system control unit 50 executes the processing of the flowchart in Fig. 4. As a result, the digital camera 100 is supplied with power of 7.5 V as an initial voltage.

[0087] In step S450, the control unit 251 determines whether or not a drop in the input voltage from the PD power adapter 205 has been detected. If it is determined that a drop in the input voltage has been detected, the process proceeds to step S452. If it is determined that a drop in the input voltage has not been detected, the process proceeds to step S451.

[0088] Here, the input voltage varies depending on the negotiation voltage. Here, the negotiation voltage is the voltage that the PD controller 252 requests from the PD power adapter 205. In this embodiment, a drop in input voltage is detected when it is detected that the input voltage is 3 V lower than the negotiation voltage. Therefore, for example, if the negotiation voltage is 15 V, the process proceeds from step S450 to step S452 when the input voltage falls below 12 V. If the negotiation voltage is 20 V, the process proceeds from step S450 to step S452 when the input voltage falls below 17 V. When a drop in input voltage is detected in step S450, the control unit 251 controls the capacitor 255 to output power to the digital camera 100. When the capacitor 255 starts supplying power, the voltage of the capacitor 255 is the same as the output voltage to the digital camera 100 immediately before. Note that the amount of drop in input voltage varies depending on the output device, and therefore the amount of drop is not particularly limited. For example, the input voltage may decrease when the USB connector 204 of the AC adapter 203 is disconnected from the PD power adapter 205. Also, in accordance with the USB PD standard, the voltage from the PD power adapter 205 may decrease after the PD power adapter 205 notifies the user that it will reduce its output voltage.

[0089] In step S451, the control unit 251 sets the communication line 263 as an input terminal because the input voltage from the PD power adapter 205 is sufficient. Specifically, the control unit 251 sets the communication line 263 as a signal line for receiving a signal from the digital camera 100.

[0090] In step S452, because the input voltage from the PD power adapter 205 is insufficient, the control unit 251 sets the communication line 263 as an output terminal and sets the signal level of the communication line 263 (= the signal level of the signal line between the power control unit 80 and the power supply unit 30) to the L level. Specifically, the control unit 251 sets the communication line 263 as a signal line that does not accept signals from the digital camera 100, and fixes the signal level of the communication line 263 to the L level.

[0091] Note that the system control unit 50 is set in step S316 to detect, via an interrupt, that the signal level on the signal line between the power control unit 80 and the power supply unit 30 has changed to L level. Therefore, when the signal level on the communication line 263 is set to L level, the system control unit 50 detects that the signal level on the signal line between the power control unit 80 and the power supply unit 30 has changed to L level. Then, the system control unit 50 immediately executes processing to control the power supply of the digital camera 100 (processing of the flowchart in FIG. 7 to be described later).

[0092] In step S453, the control unit 251 determines whether the output voltage from the capacitor 255 to the digital camera 100 is an abnormally low voltage. After the power supply is switched to the capacitor 255 in step S450, the charge accumulated in the capacitor 255 gradually decreases, and the output voltage also decreases. If the negotiation voltage is 20V, when the input voltage falls below 20V by a predetermined value, the power supply is switched to the capacitor 255. In this example, when it is detected that the input voltage has dropped below 17V, which is 3V lower than 20V, the power supply is switched to that from capacitor 255. At this time, the output voltage of capacitor 255 immediately after the switch (= the output voltage to digital camera 100) is 8.5V, which is half of 17V. Therefore, for example, control unit 251 determines whether the output voltage to digital camera 100 is an abnormally low voltage by determining whether the output voltage to digital camera 100 is a voltage lower than a predetermined voltage of 6V. If it is determined that the output voltage to digital camera 100 is an abnormally low voltage, the process proceeds to step S455. If it is determined that the output voltage to digital camera 100 is not an abnormally low voltage, the process proceeds to step S454.

[0093] In step S454, control unit 251 determines whether the input voltage from PD power adapter 205 has returned to 15 V. If it is determined that the input voltage from PD power adapter 205 has not returned to 15 V, control unit 251 returns to step S453. If it is determined that the input voltage has returned to 15 V, control unit 251 proceeds to step S450.

[0094] For example, after the PD power adapter 205 and AC adapter 203 are disconnected and a drop in the input voltage of the AC adapter 203 is detected, the PD power adapter 205 and AC adapter 203 may be reconnected while power is being supplied from capacitor 255 to digital camera 100. In this case, as described above, the control unit 251 performs the same processes as steps S400 to S402 and detects that the input voltage has reached 15 V. Furthermore, after a drop in the input voltage of the AC adapter 203 is detected, while power is being supplied from capacitor 255 to digital camera 100, the PD power adapter 205 notifies the control unit 251 that it will increase its output voltage to 15 V in accordance with the USB PD standard, and then the control unit 251 detects that the voltage from the PD power adapter 205 has reached 15 V.

[0095] In step S455, the control unit 251 turns off the FET 256. As a result, the control unit 251 stops supplying power to the power supply control unit 80 of the digital camera 100.

[0096] In step S405, the control unit 251 determines the signal level of the communication line 263. If it is determined that the signal level of the communication line 263 is H level, it is determined that communication between the digital camera 100 and the AC adapter 203 is not occurring, and the process returns to step S450. On the other hand, if the signal level of the communication line 263 is L level, it is considered that "communication is occurring" or "the AC adapter 203 has been removed from the slot 201." Therefore, if it is determined that the signal level of the communication line 263 is L level, the process proceeds to step S406 to determine which event has occurred.

[0097] In step S406, the control unit 251 uses the non-attachment determination timer to measure the time (duration) during which the signal level of the communication line 263 continues to be at L level. If the timer is currently measuring the duration, the process proceeds to step S407. If the timer has finished measuring the duration, the process determines that the AC adapter 203 is removed from the slot 201, and the process proceeds to step S418. In the first embodiment, the timer measures the time during which the signal level of the communication line 263 continues to be at L level for a predetermined period of time (for example, 500 ms), and then ends the measurement.

[0098] In step S407, control unit 251 determines the signal level of communication line 263. If it is determined that the signal level of communication line 263 is H level, it is determined that communication is taking place between digital camera 100 and AC adapter 203 because the signal level became H level while the timer was timing, and the process proceeds to step S408. If it is determined that the signal level of communication line 263 is maintained at L level, the process returns to step S406.

[0099] In step S408, the control unit 251 receives the data (including the command) sent from the power supply control unit 80 to the AC adapter 203.

[0100] In step S409, the control unit 251 stops the non-wearing determination timer and clears the count value of the duration (sets it to 0).

[0101] In step S410, the control unit 251 determines whether the command acquired in step S408 (hereinafter referred to as the "acquisition command") is a type determination command (a command requesting type determination of the power supply unit 30). If it is determined that the acquisition command is a type determination command, the process proceeds to step S411. If it is determined that the acquisition command is not a type determination command, the process proceeds to step S413.

[0102] In step S411, the control unit 251 reads type information from the nonvolatile memory 264. The type information includes information indicating whether the power supply unit 30 is the battery 300 or the AC adapter 203, information indicating whether the power supply unit 30 is compatible with USB PD, information determined by the AC adapter 203, and the like.

[0103] In step S412, the control unit 251 transmits the type information obtained in step S411 to the power supply control unit 80 (digital camera 100).

[0104] In step S413, the control unit 251 determines whether the obtain command is a 10V command (a command requesting the output of a voltage of 10V). If it is determined that the obtain command is a 10V command, the process proceeds to step S414. If it is determined that the obtain command is not a 10V command, the process proceeds to step S415.

[0105] In step S414, the control unit 251 requests the PD power adapter 205 to supply 20V power (negotiates with the PD power adapter 205). In this case, the control unit 251 controls the PD controller 252 to communicate with the PD power adapter 205.

[0106] In step S415, the control unit 251 determines whether the acquisition command is a command requesting an output voltage response (hereinafter referred to as a "response command"). If it is determined that the acquisition command is a response command, the process proceeds to step S416. If it is determined that the acquisition command is not a response command, the process returns to step S404.

[0107] In step S416, the control unit 251 controls the output voltage detection unit 260 to detect the output voltage.

[0108] In step S417, the control unit 251 transmits to the power supply control unit 80 the information on the output voltage (information on the value of the output voltage) obtained in step S416.

[0109] In step S418, the control unit 251 communicates with the PD controller 252 to determine the current negotiation voltage. If it is determined that the negotiation voltage is 20 V, the process proceeds to step S419. If it is not determined that the negotiation voltage is 20 V, the process returns to step S404.

[0110] In step S419, the control unit 251 controls the PD controller 252 to start communication with the PD power adapter 205 and request the supply of 15V power (performs negotiation). Note that if the process of step S418 is not performed and the timer has finished measuring the duration in step S406, the process proceeds to step S419. Good too.

[0111] Referring to the flowchart of FIG. 7, the process executed in response to an interrupt caused by setting the signal level of the communication line 263 to L level in step S452 will be described.

[0112] In step S500, the system control unit 50 determines the startup state of the digital camera 100. The system control unit 50 determines whether the digital camera 100 is in a "power-on state (starting up state) which is the state after step S308" or a "power-off state which is the state after the processing of the flowchart in FIG. 5 has been performed and completed." If it is determined that the digital camera 100 is in a power-on state, the process proceeds to step S502. If it is determined that the digital camera 100 is in a power-off state, the process proceeds to step S501.

[0113] In step S501, the system control unit 50 executes the processing of the flowchart in FIG. 4. As described above, after a drop in the input voltage of the AC adapter 203 is detected in step S450, processing is executed using power from the AC adapter 203 until it is determined in step S453 that the output voltage to the digital camera 100 is abnormally low. However, because the input voltage of the AC adapter 203 has dropped, it is not determined in step S314 that the output voltage is 10 V. In this state, if the output voltage from the AC adapter 203 to the digital camera 100 becomes abnormally low and the FET 256 is turned off, the power supply is stopped, and processing by the digital camera 100 is halted. On the other hand, after a drop in the input voltage of the AC adapter 203 is detected in step S450, if it becomes possible to supply a voltage of 15 V from the PD power adapter 205 in step S454, the processing of FIG. 4 is executed. In this case, the signal level of the communication line 263 is low due to the interrupt signal, so it is determined to be low in step S300 and the execution flag is set to On. As a result, a 10V command is sent to the AC adapter 203 in step S312, and the output voltage is determined to be 10V in step S314. In this case, the system control unit 50 executes the processes up to step S316. Thereafter, the digital camera 100 is put into a power-off state. At this time, the signal level of the communication line 263 when the digital camera 100 was powered off is maintained. In this case, since the process of FIG. 4 is executed in the power-off state, the process of step S308 is not executed, and the digital camera 100 enters the power-off state. The process of FIG. 4 is also executed when the digital camera 100 is not in the power-off state but in the auto-power-off state and receives an interrupt resulting from setting the signal level of the communication line 263 to the L level. In this case, after executing the processes up to step S316 as described above, the system control unit 50 puts the digital camera 100 into the power-on state.

[0114] In step S502, the system control unit 50 performs emergency shutdown processing of the digital camera 100. In the emergency shutdown processing, the system control unit 50 performs the minimum processing that should be performed before transitioning to a power-off state (minimum processing from the perspective of device protection of the imaging apparatus). In this embodiment, the system control unit 50 performs processing to terminate access to the recording medium 200. Then, the system control unit 50 temporarily puts the digital camera 100 into a power-off state.

[0115] In step S503, the system control unit 50 executes a restart process for the digital camera 100. Then, the process proceeds to step S504, where the system control unit 50 executes the process of the flowchart in FIG. 4. As described above, after a drop in the input voltage of the AC adapter 203 is detected in step S450, processing is executed using power from the AC adapter 203 until it is determined in step S453 that the output voltage to the digital camera 100 is an abnormally low voltage. However, because the input voltage of the AC adapter 203 has dropped, it is not determined in step S314 that the output voltage is 10V. In this state, In this state, if the output voltage from AC adapter 203 becomes abnormally low and FET 256 is turned off, the power supply is stopped and processing in digital camera 100 is halted. On the other hand, if a drop in the input voltage of AC adapter 203 is detected in step S450 and then a voltage of 15 V can be supplied from PD power adapter 205 in step S454, the output voltage is determined to be 10 V in step S314 as a result of the processing in Figure 4. In this case, system control unit 50 performs processing up to step S316 and then turns digital camera 100 on.

[0116] According to the first embodiment, when the digital camera 100 is powered on, if the signal level on the communication line with the AC adapter 203 is L level, the digital camera 100 will, in principle, request the AC adapter 203 to supply power at the voltage required by the digital camera 100 (requested voltage). The digital camera 100 then determines the voltage to be supplied from the AC adapter 203. On the other hand, when the signal level on the communication line with the AC adapter 203 is H level, the digital camera 100 will not request power at the requested voltage. Therefore, the digital camera 100 receives power from the AC adapter 203 at the voltage that the digital camera 100 requested most recently (before the power was turned off).

[0117] Furthermore, the digital camera 100 controls the signal level of the communication line with the AC adapter 203 when the power is turned off so that it is maintained even after the power is turned off. Therefore, if the power is turned off while the digital camera 100 is receiving 10 V, the voltage required by the AC adapter 203, the signal level of the communication line with the AC adapter 203 is maintained at H level. If the digital camera 100 is turned on again in this state, the signal level of the communication line with the AC adapter 203 is maintained at H level, so the AC adapter 203 does not perform power negotiation.

[0118] Furthermore, the digital camera 100 enables an L edge interrupt from the communication line with the AC adapter 203, and when it detects a loss of household power while the power is off, it changes the signal level of the communication line with the AC adapter 203 to L level, causing the AC adapter 203 to re-negotiate.

[0119] This reduces the impact that the processing time for power negotiation by the AC adapter 203 has on the startup time of the digital camera 100. Furthermore, if power negotiation needs to be performed, the power negotiation is performed, and therefore the AC adapter 203 can provide appropriate power to the digital camera 100.

[0120] Furthermore, even when the digital camera 100 is in a power-off state, in response to a drop in the output of the AC adapter 203, the digital camera 100 notifies the AC adapter 203 of a command (required voltage) instructing it to switch the output voltage from the AC adapter 203. As a result, the AC adapter 203 can output an output voltage that always satisfies the power required by the digital camera 100.

[0121] Furthermore, in the above, "If A is greater than or equal to B, proceed to step S1; if A is less than (lower than) B, proceed to step S2" may be read as "If A is greater than (higher than) B, proceed to step S1; if A is less than or equal to B, proceed to step S2." Conversely, "If A is greater than (higher than) B, proceed to step S1; if A is less than (lower than) B, proceed to step S2" may be read as "If A is greater than (higher than) B, proceed to step S1; if A is less than (lower than) B, proceed to step S2." Therefore, unless a contradiction arises, "greater than or equal to A" may be read as "greater than (higher; longer; more) than A," and "less than or equal to A" may be read as "less than (lower; shorter; fewer) than A." Furthermore, "greater than (higher; longer; more) than A" may be read as "greater than or equal to A," and "less than (lower; shorter; fewer) than A" may be read as "less than or equal to A."

[0122] The various controls described above may or may not be performed by a single piece of hardware (e.g., a processor or circuit). The entire device may be controlled by multiple pieces of hardware (e.g., multiple processors, multiple circuits, or a combination of one or more processors and one or more circuits) sharing the processing.

[0123] The above processor is a processor in the broad sense, and includes general-purpose processors and dedicated processors. General-purpose processors include, for example, CPUs (Central Processing Units), MPUs (Micro Processing Units), and DSPs (Digital Signal Processors). Dedicated processors include, for example, GPUs (Graphics Processing Units), ASICs (Application Specific Integrated Circuits), and PLDs (Programmable Logic Devices). Programmable logic devices include, for example, FPGAs (Field Programmable Gate Arrays) and CPLDs (Complex Programmable Logic Devices).

[0124] Although the embodiments of the present invention have been described in detail, the present invention is not limited to these specific embodiments, and various forms within the scope of the gist of the present invention are also included in the present invention. Furthermore, each of the above-described embodiments merely represents one embodiment of the present invention, and each embodiment can be combined as appropriate.

[0125] <Other embodiments> The present invention can also be realized by a process in which a program that realizes one or more functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in the computer of the system or device read and execute the program, or by a circuit that realizes one or more functions.

[0126] The disclosure of the above embodiments includes the following configurations, methods, programs, and media. (Configuration 1) An electronic device to which a predetermined accessory that supplies power is removably connected, a communication means for communicating with the predetermined accessory via a communication line, the communication means performing predetermined communication processing to request the predetermined accessory to supply power of a first voltage when the signal level of the communication line is at a first level, and not to request the predetermined accessory to supply power of the first voltage when the signal level of the communication line is at a second level when the electronic device is started up; a first setting means for setting a signal level of the communication line to the second level when the communication means requests the predetermined accessory to supply power of the first voltage; a first control means for controlling the signal level of the communication line to be maintained at the time when the power supply of the electronic device was stopped after the power supply of the electronic device was stopped; a detection means for detecting a change in the signal level of the communication line from the second level to the first level when the signal level of the communication line is set to the second level; and When the detection means detects that the signal level of the communication line has changed from the second level to the first level after the power supply of the electronic device has been stopped, the communication means requests power of the first voltage from the predetermined accessory. An electronic device characterized by: (Configuration 2) the power-off state includes a power-off state of the electronic device, the first control means, if the signal level of the communication line is set to the second level when the electronic device is turned off in response to a power-off instruction from a user, controls the level of the communication line to be maintained at the second level after the electronic device is turned off; After the electronic device has been turned off in response to the instruction, when the detection means detects that the signal level of the communication line has changed from the second level to the first level, the communication means requests power of the first voltage from the predetermined accessory, and the first control means turns the electronic device off. 2. The electronic device according to configuration 1. (Configuration 3) After the electronic device has entered the power-off state in response to a power-off instruction from the user, when the detection means detects that the signal level of the communication line has changed from the second level to the first level and the communication means requests power of the first voltage from the predetermined accessory, the first setting means sets the signal level of the communication line to the second level, and the first control means controls the electronic device to be in the power-off state, and then maintains the signal level of the communication line at the time when the power of the electronic device was stopped. 3. The electronic device according to configuration 2. (Configuration 4) the power-off state includes an auto-power-off state of the electronic device, the first control means, if the signal level of the communication line is set to the second level when the electronic device is in the auto power off state, controls the level of the communication line to be maintained at the second level after the electronic device is in the auto power off state; After the electronic device has entered the auto power-off state, when the detection means detects that the signal level of the communication line has changed from the second level to the first level, the communication means requests power of the first voltage from the predetermined accessory, and the first control means turns the electronic device into a power-on state. 2. The electronic device according to configuration 1. (Configuration 5) a power supply control means for receiving a voltage output from the predetermined accessory; The power supply control means receives the first voltage from the predetermined accessory when the first voltage is requested from the predetermined accessory, and receives a second voltage lower than the first voltage from the predetermined accessory when the first voltage is not requested from the predetermined accessory. 5. The electronic device according to any one of configurations 1 to 4. (Configuration 6) The second voltage is a predetermined voltage supplied by the predetermined accessory when the first voltage is not required by the electronic device. 6. The electronic device according to configuration 5. (Configuration 7) When the first voltage is requested by the communication means, the predetermined accessory performs a process to change the output voltage from the predetermined accessory from the second voltage to the first voltage. 7. The electronic device according to configuration 5 or 6. (Configuration 8) The predetermined accessory receives power from a power supply device in accordance with the USB Power Delivery (USB PD) standard, generates the output voltage for the electronic device from an input voltage from the power supply device, and outputs the output voltage to the electronic device; The process for changing the output voltage from the second voltage to the first voltage is a USB PD power negotiation process. 8. The electronic device according to configuration 7. (Configuration 9) The device further has slots into which the predetermined accessory and battery can be attached, When the predetermined accessory is attached to the slot, the first control means controls the communication line so as to maintain the signal level at the time when the power supply of the electronic device is turned off after the power supply of the electronic device is turned off, and when the battery is attached to the slot, the signal level of the communication line is set to the first level when the power supply of the electronic device is turned off. 9. The electronic device according to any one of configurations 1 to 8. (Configuration 10) When the detection means detects that the signal level of the communication line has changed from the second level to the first level while the electronic device is in a power-on state, the first control means executes a predetermined shutdown process for the electronic device, and then causes the communication means to perform the predetermined communication process. 10. The electronic device according to any one of configurations 1 to 9. (Configuration 11) the first level is an L level, The second level is an H level. 11. The electronic device according to any one of configurations 1 to 10. (Configuration 12) When the predetermined accessory is removed from the electronic device, the signal level of the communication line becomes the first level. 12. The electronic device according to configuration 11. (Configuration 13) When the communication means receives a request to stop the power supply from the predetermined accessory, the first control means performs processing to stop the power supply of the electronic device before the power supply from the predetermined accessory is stopped, and the signal level of the communication line becomes the first level. 12. The electronic device according to configuration 11. (Configuration 14) When the supply of power from the predetermined accessory is stopped, the signal level of the communication line becomes the first level. 12. The electronic device according to configuration 11. (Configuration 15) A system including the electronic device according to any one of configurations 1 to 14 and the predetermined accessory, The predetermined accessory is a supplying means for receiving an input voltage from a power supply device, and generating an output voltage from the input voltage when the input voltage is higher than a predetermined level, and supplying the output voltage to the electronic device; a second control means for controlling the supply means to supply the output voltage of a second voltage lower than the first voltage when there is no request from the communication means to supply power of the first voltage, and to supply the output voltage of the first voltage when there is a request from the communication means; a second setting means for setting the signal level of the communication line to the first level when the input voltage is lower than the predetermined level; and The second control means prevents the supply means from changing the output voltage to the first voltage when the signal level of the communication line is maintained at the second level. A system characterized by: (Configuration 16) The supply means If the request is not made from the communication means, a third voltage corresponding to the second voltage is requested from the power supply device, and the second voltage is generated from the third voltage, which is the input voltage, and is supplied to the electronic device; When performing a process of changing the output voltage to the first voltage, a fourth voltage corresponding to the first voltage is requested from the power supply device, and the first voltage is generated from the fourth voltage, which is the input voltage, and is supplied to the electronic device. 16. The system of claim 15. (method) A method for controlling an electronic device to which a predetermined accessory that supplies power is removably connected, comprising: a communication step of performing communication processing with the predetermined accessory via a communication line, in which, when the signal level of the communication line is at a first level, the predetermined accessory is requested to supply power of a first voltage, and when the signal level of the communication line is at a second level, the predetermined accessory is not requested to supply power of the first voltage; a first setting step of setting a signal level of the communication line to the second level when the predetermined accessory is requested to supply power of the first voltage in the communication step; a first control step of performing control so as to maintain the signal level of the communication line at the time when the power supply of the electronic device was stopped after the power supply of the electronic device was stopped; a detecting step capable of detecting, when the signal level of the communication line is set to the second level, that the signal level of the communication line has changed from the second level to the first level; and When it is detected in the detecting step that the signal level of the communication line has changed from the second level to the first level after the power supply of the electronic device has been stopped, the communicating step requests the predetermined accessory for power of the first voltage. 10. A method for controlling an electronic device comprising: (program) A program for causing a computer to function as each means of the electronic device described in any one of configurations 1 to 14. (medium) A computer-readable storage medium storing a program for causing a computer to function as each means of the electronic device described in any one of configurations 1 to 14. [Explanation of symbols]

[0127] 100: Digital camera (electronic device), 54: Communication unit, 50: System control unit

Claims

1. An electronic device to which a predetermined accessory that supplies power is removably connected, a communication means for communicating with the predetermined accessory via a communication line, the communication means performing predetermined communication processing to request the predetermined accessory to supply power of a first voltage when the signal level of the communication line is a first level, and not to request the predetermined accessory to supply power of the first voltage when the signal level of the communication line is a second level, when the electronic device is started up; a first setting means for setting a signal level of the communication line to the second level when the communication means requests the predetermined accessory to supply power of the first voltage; a first control means for controlling the signal level of the communication line to be maintained at the time when the power supply of the electronic device was stopped after the power supply of the electronic device was stopped; a detection means for detecting a change in the signal level of the communication line from the second level to the first level when the signal level of the communication line is set to the second level; and When the detection means detects that the signal level of the communication line has changed from the second level to the first level after the power supply of the electronic device has been stopped, the communication means requests power of the first voltage from the predetermined accessory. An electronic device characterized by:

2. the power-off state includes a power-off state of the electronic device, the first control means, when the signal level of the communication line is set to the second level when the electronic device is turned off in response to a power-off instruction from a user, controls the level of the communication line to be maintained at the second level after the electronic device is turned off; After the electronic device has been turned off in response to the instruction, when the detection means detects that the signal level of the communication line has changed from the second level to the first level, the communication means requests power of the first voltage from the predetermined accessory, and the first control means turns the electronic device off.

2. The electronic device according to claim 1, wherein the electronic device is a semiconductor device.

3. After the electronic device has entered the power-off state in response to a power-off instruction from the user, when the detection means detects that the signal level of the communication line has changed from the second level to the first level and the communication means requests power of the first voltage from the predetermined accessory, the first setting means sets the signal level of the communication line to the second level, and the first control means, after placing the electronic device in the power-off state, controls the electronic device to maintain the signal level of the communication line at the time when the power of the electronic device was stopped.

3. The electronic device according to claim 2.

4. the power-off state includes an auto-power-off state of the electronic device, the first control means, if the signal level of the communication line is set to the second level when the electronic device is in the auto power off state, controls the level of the communication line to be maintained at the second level after the electronic device is in the auto power off state; After the electronic device has entered the auto power-off state, when the detection means detects that the signal level of the communication line has changed from the second level to the first level, the communication means requests power of the first voltage from the predetermined accessory, and the first control means turns the electronic device into a power-on state.

2. The electronic device according to claim 1, wherein the electronic device is a semiconductor device.

5. a power supply control means for receiving a voltage output from the predetermined accessory; The power supply control means receives the first voltage from the predetermined accessory when the first voltage is requested from the predetermined accessory, and receives a second voltage lower than the first voltage from the predetermined accessory when the first voltage is not requested from the predetermined accessory.

2. The electronic device according to claim 1, wherein the electronic device is a semiconductor device.

6. The second voltage is a predetermined voltage supplied by the predetermined accessory when the first voltage is not required by the electronic device.

6. The electronic device according to claim 5.

7. When the first voltage is requested by the communication means, the predetermined accessory performs a process to change the output voltage from the predetermined accessory from the second voltage to the first voltage.

6. The electronic device according to claim 5.

8. The predetermined accessory receives power from a power supply device in accordance with the USB Power Delivery (USB PD) standard, generates the output voltage for the electronic device from an input voltage from the power supply device, and outputs the output voltage to the electronic device; The process for changing the output voltage from the second voltage to the first voltage is a process of power negotiation of a USB PD.

8. The electronic device according to claim 7,

9. The device further has slots into which the predetermined accessory and battery can be attached, When the predetermined accessory is attached to the slot, the first control means controls the signal level of the communication line to be maintained after the power supply of the electronic device is turned off, and when the battery is attached to the slot, the signal level of the communication line is set to the first level when the power supply of the electronic device is turned off.

2. The electronic device according to claim 1, wherein the electronic device is a semiconductor device.

10. When the detection means detects that the signal level of the communication line has changed from the second level to the first level while the electronic device is in a power-on state, the first control means executes a predetermined shutdown process for the electronic device, and then causes the communication means to perform the predetermined communication process.

2. The electronic device according to claim 1, wherein the electronic device is a semiconductor device.

11. the first level is an L level, The second level is an H level.

2. The electronic device according to claim 1, wherein the electronic device is a semiconductor device.

12. When the predetermined accessory is removed from the electronic device, the signal level of the communication line becomes the first level.

12. The electronic device according to claim 11.

13. When the communication means receives a request to stop the power supply from the predetermined accessory, the first control means performs processing to stop the power supply of the electronic device before the power supply from the predetermined accessory is stopped, and the signal level of the communication line becomes the first level.

12. The electronic device according to claim 11.

14. When the supply of power from the predetermined accessory is stopped, the signal level of the communication line becomes the first level.

12. The electronic device according to claim 11.

15. A system including the electronic device according to any one of claims 1 to 14 and the predetermined accessory, The predetermined accessory is a supplying means for receiving an input voltage from a power supply device, and generating an output voltage from the input voltage when the input voltage is higher than a predetermined level, and supplying the output voltage to the electronic device; a second control means for controlling the supply means to supply the output voltage of a second voltage lower than the first voltage when no request to supply power of the first voltage is made from the communication means, and to supply the output voltage of the first voltage when the request is made from the communication means; a second setting means for setting the signal level of the communication line to the first level when the input voltage is lower than the predetermined level; and The second control means prevents the supply means from changing the output voltage to the first voltage when the signal level of the communication line is maintained at the second level. A system characterized by:

16. The supply means If the request is not made from the communication means, a third voltage corresponding to the second voltage is requested from the power supply device, and the second voltage is generated from the third voltage, which is the input voltage, and is supplied to the electronic device; When performing a process of changing the output voltage to the first voltage, a fourth voltage corresponding to the first voltage is requested from the power supply device, and the first voltage is generated from the fourth voltage, which is the input voltage, and is supplied to the electronic device.

16. The system of claim 15.

17. A method for controlling an electronic device to which a predetermined accessory that supplies power is removably connected, comprising: a communication step of performing a predetermined communication process in which, when the signal level of the communication line is a first level, the predetermined accessory is requested to supply power of a first voltage, and when the signal level of the communication line is a second level, the predetermined accessory is not requested to supply power of the first voltage; a first setting step of setting a signal level of the communication line to the second level when the predetermined accessory is requested to supply power of the first voltage in the communication step; a first control step of performing control so as to maintain the signal level of the communication line at the time when the power supply of the electronic device was stopped after the power supply of the electronic device was stopped; a detecting step capable of detecting, when the signal level of the communication line is set to the second level, that the signal level of the communication line has changed from the second level to the first level; and When it is detected in the detecting step that the signal level of the communication line has changed from the second level to the first level after the power supply of the electronic device has been stopped, the communicating step requests the predetermined accessory for power of the first voltage. do A method for controlling an electronic device.

18. A program for causing a computer to function as each of the means of the electronic device according to any one of claims 1 to 14.

19. A computer-readable storage medium storing a program for causing a computer to function as each of the means of the electronic device according to any one of claims 1 to 14.

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