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

Abstract

In an electronic device capable of requesting the voltage of the power received from an accessory, an increase in the startup time of the electronic device is prevented. 【Solution means】An electronic device to which an accessory that supplies power is removably connected includes means for communicating with the accessory via a communication line. When the signal level of the communication line is at a first level at the time of startup of the electronic device, the accessory is requested to supply power at a first voltage. When the signal level of the communication line is at a second level, communication means that does not request the accessory to supply power at the first voltage; setting means for setting the signal level of the communication line to the second level when the communication means requests the accessory to supply power at the first voltage; and control means for controlling to maintain the signal level of the communication line at the time of power-off of the electronic device after the power of the electronic device is stopped.

Description

Technical Field

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

Background Art

[0002] Conventionally, a power adapter for supplying power to an imaging device is known. The power adapter has a shape that can be attached to the battery chamber of the imaging device, and by attaching the power adapter to the battery chamber instead of the battery, power can be supplied to the imaging device from a household power supply or the like. In addition, by unifying the shape of the battery chamber among different models, batteries and power accessories can be commonly used among different models.

[0003] In addition, due to the multifunctionalization of imaging devices and the like, the power consumption of imaging devices has been increasing. With the increase in power consumption, a power accessory that can supply larger power is required. On the other hand, it is also effective to enable the use of a power accessory that can supply such a large amount of power even for an imaging device of a conventional product that has the same battery chamber shape and does not have a large power consumption. For this purpose, it is desirable that the power accessory can supply power suitable for the imaging device to which it is attached. For example, it is sufficient if the power accessory can output an appropriate voltage and current according to the connected imaging device.

[0004] Conventionally, a power supply standard corresponding to a USB Type-C terminal, called the USB Power Delivery standard (USB PD project), is known. And imaging devices and various devices corresponding to USB PD are widespread. According to the USB PD standard, a power supply device can supply a plurality of voltages and currents, and a power receiving device can request a desired voltage among the plurality of voltages that the power supply device can output. Therefore, it is effective for a power accessory to have the function of a power receiving device corresponding to USB PD.

[0005] Patent Document 1 describes a DC adapter device having a function of "supplying a driving power source to an electronic device powered by a dry battery". However, it does not mention supplying different voltages depending on the electronic device.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Since the power accessory has a function as a power receiving device of the USB PD standard, it becomes possible to receive different voltages from the power supply device. Therefore, the power accessory can request a voltage corresponding to the imaging device connected to the power accessory and supply it to the imaging device. On the other hand, in USB PD, when the power supply device and the power receiving device are connected, power negotiation is performed, and after the power receiving device requests a desired voltage from the power supply device, power is supplied from the power supply device. When the imaging device receives power from a power accessory corresponding to USB PD, at the time of starting up the imaging device, it is necessary to wait for the requested voltage to be output from the power supply device after the power accessory performs power negotiation with the USB PD power supply device in this way. Thus, there are a plurality of procedures until a desired voltage is supplied from the power accessory to the imaging device. And it is desirable that the imaging device executes the startup process after the necessary power is supplied from the power adapter to the imaging device. Therefore, there is a problem that the startup time of the imaging device increases.

[0008] Therefore, an object of the present invention is to prevent an increase in the startup time of an electronic device that can request the voltage of the power received from an accessory.

Means for Solving the Problems

[0009] One aspect of the present invention is An electronic device to which a predetermined accessory for supplying power is removably connected, means for communicating with the predetermined accessory via a communication line, wherein when the signal level of the communication line is at a first level at startup of the electronic device, the predetermined accessory is requested to supply power at 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 at the first voltage; a communication means that does not perform the above; setting means for setting the signal level of the communication line to the second level when the communication means requests the predetermined accessory to supply power at the first voltage; control means for controlling to maintain the signal level of the communication line at the time of power-off of the electronic device after the power of the electronic device is turned off; Power control means for receiving the voltage output from the predetermined accessory having and the power control means when the first voltage is requested from the predetermined accessory by the communication means, receives the first voltage from the predetermined accessory when the first voltage is not requested from the predetermined accessory by the communication means, receives a second voltage lower than the first voltage from the predetermined accessory when the first voltage is requested by the communication means, the predetermined accessory performs a process for changing the output voltage from the predetermined accessory from the second voltage to the first voltage the predetermined accessory receives power from a power supply device according to the USB Power Delivery (USB PD) standard, generates an output voltage from the input voltage from the power supply device to the electronic device, and outputs the output voltage to the electronic device the process for changing is a power negotiation process of USB PD An electronic device characterized by the above.

[0010] One aspect of the present invention is A control method for an electronic device to which a predetermined accessory for supplying power is removably connected, a step of communicating with the predetermined accessory via a communication line, wherein when the signal level of the communication line is at a first level at startup of the electronic device, the predetermined accessory is requested to supply power at 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 at the first voltage; a communication step that does not perform the above; When requesting the predetermined accessory to supply the power of the first voltage in the communication step, a setting step of setting the signal level of the communication line to the second level; A control step of controlling to maintain the signal level of the communication line at the time of stopping the power supply of the electronic device after the power supply of the electronic device is stopped; a power control step for receiving the voltage output from the predetermined accessory comprises and in the power control step when the first voltage is requested from the predetermined accessory in the communication step, receives the first voltage from the predetermined accessory when the first voltage is not requested from the predetermined accessory in the communication step, receives a second voltage lower than the first voltage from the predetermined accessory when the first voltage is requested in the communication step, the predetermined accessory performs a process for changing the output voltage from the predetermined accessory from the second voltage to the first voltage the predetermined accessory receives power from a power supply device according to the USB Power Delivery (USB PD) standard, generates an output voltage from the input voltage from the power supply device to the electronic device, and outputs the output voltage to the electronic device the process for changing is a power negotiation process of USB PD It is a control method characterized by the above.

Effect of the Invention

[0011] According to the present invention, in an electronic device capable of requesting the voltage of the power received from an accessory, an increase in the startup time of the electronic device can be prevented.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

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

[0014] <Embodiment 1> In Embodiment 1, power negotiation regarding a "digital camera" and an "AC adapter compatible with USB PD" will be described. Regarding power negotiation, it 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 types of information. The shutter button 61 is an operation unit for giving a shooting instruction. The mode 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) for receiving 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 includes a USB connector 204. The USB connector 204 is connected to a PD power adapter 205 which is a power supply device compatible with USB Power Delivery (USB PD). The PD power adapter 205 is a power supply device connected to a household power supply via a plug 206. When a power receiving device compatible with USB PD is connected to the PD power adapter 205 via a USB Type-C cable, power supply according to the USB PD standard is performed from the PD power adapter 205. In FIG. 1, the AC adapter 203, which is a power receiving device compatible with USB PD, is connected to the PD power adapter 205, and power is supplied from the PD power adapter 205 to the AC adapter 203 according to the USB PD standard. In this way, stable power is supplied from the PD power adapter 205 to the digital camera 100 via the AC adapter 203.

[0017] Slot 201 is a slot for storing the recording medium 200 and the AC adapter 203. Slot 201 has a battery compartment (not shown). When the battery 300 is used as the power source of the digital camera 100, the battery 300 is mounted in the battery compartment. Also, when the AC adapter 203 is used as the power source of the digital camera 100, the AC adapter 203 is mounted in the battery compartment instead of the battery 300. The battery 300 and the AC adapter 203 have the same shape. The user can easily mount either the battery 300 or the AC adapter 203 to the battery compartment, and can also easily discharge them from the battery compartment. Further, the battery compartment is provided with terminals for the digital camera 100 to communicate with the battery 300 or the AC adapter 203, and terminals for receiving power. By connecting the terminals on the battery 300 or the AC adapter 203 side to these terminals, power supply and communication from the battery 300 or the AC adapter 203 become possible. Since the recording medium 200 stored in the slot 201 can communicate with the digital camera 100, it is possible to record and play back the images acquired from the digital camera 100. The lid 202 is the lid of the slot 201. FIG. 1 shows a state in which the lid 202 is opened and a part of the recording medium 200 and a part of the AC adapter 203 are taken out from the slot 201 and exposed.

[0018] FIG. 2 is a block diagram showing a configuration example of the digital camera 100 according to Embodiment 1. 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 image sensor (imaging device) composed of a CCD, a CMOS element, etc. that convert 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, the shutter 101, and the imaging unit 22), thereby preventing dirt and damage to the imaging system.

[0019] The image processing unit 24 performs image processing (resize processing such as predetermined pixel interpolation and reduction, and color conversion processing) on the data from the A / D converter 23 or the data from the memory control unit 15. Further, the image processing unit 24 performs predetermined arithmetic processing using the captured image data. Based on the arithmetic result obtained by the image processing unit 24, the system control unit 50 performs exposure control and distance measurement control. As a result, TTL (through-the-lens) type AF (auto focus) processing, AE (auto exposure) processing, and EF (flash pre-emission) processing are performed. The image processing unit 24 further performs predetermined arithmetic processing using the captured image data. The image processing unit 24 performs TTL type AWB (auto white balance) processing based on the obtained arithmetic result.

[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 the memory control unit 15. The memory 32 stores the image data obtained by the imaging unit 22 and converted into digital data by the A / D converter 23. The memory 32 stores the image data for display on the display unit 28. The memory 32 has a storage capacity sufficient to store a predetermined number of still images, a moving image for a predetermined time, and audio.

[0021] Also, the memory 32 also serves as an image display memory (video memory). 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. In this way, the image data for display written in the memory 32 is transmitted to the display unit 28 via the D / A converter 13. The display unit 28 performs display according to the analog signal from the D / A converter 13 on a display such as an LCD. Once A / D conversion is performed by the A / D converter 23, a digital signal is accumulated in the memory 32. The digital signal is subjected to analog conversion in the D / A converter 13, and the signal after analog conversion is sequentially transferred to the display unit 28. Thereby, the display unit 28 functions as an electronic viewfinder and performs through-image display (live view display (LV display)). Hereinafter, the image displayed in the live view is referred to as an LV image.

[0022] The non-volatile memory 56 is an electrically erasable and recordable recording medium. For the non-volatile memory 56, for example, an EEPROM or the like is used. Constants for the operation of the system control unit 50, programs, etc. are stored in the non-volatile memory 56. Here, the program refers to a computer program for executing various flowcharts described later in Embodiment 1.

[0023] The system control unit 50 is a control unit composed 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 realizes each process of Embodiment 1 described later by executing the program recorded in the non-volatile memory 56 described above. For the system memory 52, for example, a RAM is used. Constants for the operation of the system control unit 50, variables, programs read from the non-volatile memory 56, etc. are expanded in the system memory 52. Also, the system control unit 50 performs display control by controlling the memory 32, the D / A converter 13, the display unit 28, etc.

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

[0025] The mode switch 60, the shutter button 61, and the operation unit 70 are operation members for inputting various operation instructions to the system control unit 50. The mode switch 60 The operation mode of the system control unit 50 is switched to any one of a still image recording mode, a moving image shooting mode, a playback mode, etc. The modes included in the still image recording mode are an auto shooting mode, an auto scene discrimination mode, a manual mode, an aperture priority mode (Av mode), a shutter speed priority mode (Tv mode), and a program AE mode. Further, the modes included in the still image recording mode are various scene modes, custom modes, etc., which are shooting settings according to the shooting scene. By using the mode change switch 60, the user can directly switch to any of these modes. Alternatively, after once switching to a list screen of the shooting modes with the mode change switch 60, any one of the plurality of displayed modes may be selected and switched using other operation members. Similarly, the moving image shooting mode may also include a plurality of modes.

[0026] When the first shutter switch 62 is turned on during the operation of the shutter button 61 provided on the digital camera 100, that is, when it is half-pressed (shooting preparation instruction), the first shutter switch signal SW1 is generated. By the generation of the first shutter switch signal SW1, operations such as AF (auto focus) processing, AE (auto exposure) processing, AWB (auto white balance) processing, and EF (flash pre-emission) processing are started.

[0027] When the second shutter switch 64 is turned on when the operation of the shutter button 61 is completed, that is, when it is fully pressed (shooting instruction), the second shutter switch signal SW2 is generated. The system control unit 50 starts a series of shooting processes (processes from reading the signal from the imaging unit 22 to writing the image data to the recording medium 200) by the generation of the second shutter switch signal SW2.

[0028] Each operating member of the operation unit 70 functions as various function buttons. For each operating member of the operation unit 70, functions are appropriately assigned for each scene by, for example, selecting and operating various function icons displayed on the display unit 28. Examples of the function buttons include an end button, a return button, an image advance button, a jump button, a narrowing-down button, an attribute change button, and the like. For example, when the menu button is pressed, various configurable menu screens are displayed on the display unit 28. The user can intuitively perform various settings using the menu screen displayed on the display unit 28 and the four-direction buttons (up, down, left, and right) and the SET button.

[0029] The controller wheel 73 is a rotatable operating member included in the operation unit 70. The controller wheel 73 is used when indicating a selection item together with the direction buttons. When the controller wheel 73 is rotated, an electrical pulse signal is generated according to the amount of operation, and based on this pulse signal, the system control unit 50 controls each part of the digital camera 100. With this pulse signal, it is possible to determine the angle by which the controller wheel 73 has been rotated and the number of rotations. Note that the controller wheel 73 may be any member as long as it is an operating member capable of detecting a rotational operation. For example, it may be a dial operating member in which the controller wheel 73 itself rotates in response to the user's rotational operation to generate a pulse signal. Alternatively, it may be an operating member composed of a touch sensor, in which the controller wheel 73 itself does not rotate, and which detects the rotational movement of the user's finger on the controller wheel 73 (so-called touch wheel).

[0030] The power control unit 80 is composed of a battery detection circuit, a DC-DC converter, a switch circuit (a circuit for switching the energized block), and the like. The power control unit 80 detects the presence or absence of battery installation, the type of battery, and the remaining battery level. Further, the power control unit 80 controls the DC-DC converter based on the detection result and the instruction of the system control unit 50, and supplies the necessary voltage to each part including the recording medium 200 for the necessary period.

[0031] The power supply unit 30 includes a battery 300 and an AC adapter 203. The battery 300 includes, for example, a primary battery (such as an alkaline battery or a lithium battery), and a secondary battery (such as a NiCd battery, a NiMH battery, or a Li battery). In Embodiment 1, a case where the AC adapter 203 is attached to the slot 201 to constitute the power supply unit 30 will be described. The power supply unit 30 may be included in the digital camera 100, but in Embodiment 1, it will be described assuming that it is not included in the digital camera 100. Therefore, Embodiment 1 is an embodiment for describing a system including the digital camera 100, the power supply unit 30 (AC adapter 203), the PD power adapter 205, and the like.

[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 the captured image. The recording medium 200 has a semiconductor memory, an optical disk, a magnetic disk, or the like.

[0033] The communication unit 54 is connected by a wireless or 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. Further, the communication unit 54 can communicate with an external device via Bluetooth (registered trademark) or Bluetooth Low Energy. The communication unit 54 can transmit an image captured by the imaging unit 22 (including a live image) or an image recorded on the recording medium 200. Also, the communication unit 54 can receive image data and various other information from an external device.

[0034] The posture detection unit 55 detects the posture of the digital camera 100 with respect to the direction of gravity. Based on the posture detected by the posture detection unit 55, it is possible to determine "whether the image captured by the imaging unit 22 is an image captured with the digital camera 100 held horizontally or an image captured with it held vertically". The system control unit 50 can add orientation information corresponding to the posture detected by the posture detection unit 55 to the image file of the image captured by the imaging unit 22, or rotate and record the image. As the posture detection unit 55, an acceleration sensor, a gyro sensor, or the like can be used. The posture detection unit 55 can also detect the movement of the digital camera 100 (such as panning, tilting, lifting, whether it is stationary, etc.) using an acceleration sensor or a gyro sensor.

[0035] FIG. 3 is a block diagram showing a configuration example of the AC adapter 203 according to Embodiment 1.

[0036] The terminal 250 is an electrical contact with the digital camera 100. The terminal 250 includes a power terminal and a communication terminal. By connecting the communication terminal and the communication line 263 to each other, communication between the power control unit 80 and the control unit 251 by the communication unit 257 is enabled.

[0037] The PD controller 252 communicates with the PD power adapter 205 when the PD power adapter 205 is connected to the USB connector 204. Also, the PD controller 252 is connected to the control unit 251. The registers of the PD controller 252 can be changed by the control unit 251.

[0038] The switched capacitor 253 is a switched capacitor type DCDC converter. The switched capacitor 253 converts the input voltage to one over an integer and outputs (generates) the output voltage. Here, the switched capacitor 253 converts the input voltage to 1 / 2 (half) and outputs it.

[0039] The capacitor 255 is a high-capacity capacitor capable of ensuring the power used for the digital camera 100 to perform shutdown processing. Since the capacitor 255 is connected to the output of the switched capacitor 253, it holds the output voltage (the voltage output from the AC adapter 203 to the digital camera 100).

[0040] The discharge circuit 254 discharges the charge of the capacitor 255 under the control of the control unit 251. The FET 256 is a field-effect transistor. The FET 256 controls the power output of the AC adapter 203 under the control of the control unit 251.

[0041] 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.

[0042] The device detection unit 258 detects whether the AC adapter 203 is mounted on the slot 201 of the digital camera 100.

[0043] The USB connection detection unit 259 detects whether the PD power adapter 205 is connected to the USB connector 204. The output voltage detection unit 260 performs A / D conversion on the signal of the output voltage wiring 262 to detect the output voltage. The non-volatile memory 264 holds the operation parameters.

[0044] When the USB connector 204 is connected to the PD power adapter 205, first, 5V is supplied as the input voltage from the PD power adapter 205, and each part of the AC adapter 203 is activated. Subsequently, the PD controller 252 performs power negotiation with the PD power adapter 205 via the USB connector 204 and requests the PD power adapter 205 to supply power of 15V / 3A. Then, when 15V of power is supplied from the PD power adapter 205, the input voltage is converted to half by the switched capacitor 253, and 7.5V, which is half of 15V, is output as the voltage to the terminal 250. Thus, in the initial state immediately after the activation of the AC adapter 203, a voltage of 7.5V (initial voltage) is output from the terminal 250. As will be described later, when a command requesting an output voltage of 10V from the digital camera 100 is not transmitted, the AC adapter 203 outputs an output voltage of 7.5V. The control unit 251 can also control the PD controller 252 to perform power negotiation requesting the supply of 20V / 3A of power. Also in this case, since the input voltage is converted to half by the switched capacitor 253, a voltage of 10V is output to the terminal 250. The digital camera 100 according to Embodiment 1 is designed to be operable at a voltage of 10V. It is also conceivable that another model of digital camera connectable to the AC adapter 203 is designed to be operable at a voltage of 7.5V. In Embodiment 1, the case where voltages of 10V and 7.5V can be output from the AC adapter 203 will be described, but the output voltage is not limited to these. For example, when the AC adapter 203 can be connected to a plurality of models of digital cameras, in order to prevent the digital camera 100 from malfunctioning due to the supply of high-voltage power to the digital camera 100, the initial voltage can be the lowest voltage among the voltages required by these plurality of models of digital cameras.

[0045] Referring to the flowchart of FIG. 4, among the processes executed by the system control unit 50, the process at the time of starting up the digital camera 100 (electronic device) will be described. The process of FIG. 4 is performed by the CPU of the system control unit 50 executing a program stored in the nonvolatile memory 56. Hereinafter, the communication between the digital camera 100 and the power supply unit 30 is controlled by the communication unit 54 in the digital camera 100. Also, the startup here includes the process of starting up when the user instructs power-on by operating the power switch 72 while the digital camera 100 is in the power-off state. Further, it includes the process of starting up when the digital camera 100 resumes from the auto power-off state.

[0046] 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 control unit 80. Here, when the communication line is set to I(p.u.) that enables the internal pull-up setting, the communication between the system control unit 50 and the control unit 251 in the AC adapter 203 is not performed. Therefore, in this case, the H level is read as the signal level of the communication line. When it is determined that the signal level of the communication line is the H level, the process proceeds to step S301. When it is determined that the signal level of the communication line is the L level, the process proceeds to step S302. In step S301, the system control unit 50 sets the negotiation execution flag (hereinafter referred to as the "execution flag"), which is a "flag indicating whether the power supply unit 30 performs negotiation", to Off. Then, the system control unit 50 holds the execution flag set to Off (the execution flag indicating that negotiation is not performed) in the RAM of the system memory 52.

[0047] In step S302, after setting the execution flag to On, the system control unit 50 holds the execution flag (the execution flag indicating that negotiation is performed) in the RAM of the system memory 52.

[0048] In step S302, after setting the execution flag to On, the system control unit 50 holds the execution flag (the execution flag indicating that negotiation is performed) in the RAM of the system memory 52.

[0049] In step S303, the system control unit 50 controls the power control unit 80 and the power supply unit 30 to be able to communicate with each other by disabling the pull-up operation of the communication line between the power control unit 80 and the power supply unit 30. Note that the pull-up may be either built-in or external, but it is assumed that the built-in pull-up is used in Embodiment 1.

[0050] In step S304, the system control unit 50 controls the power control unit 80 to transmit a command (hereinafter referred to as the "type determination command") for instructing the determination of the type (battery type) of the power supply unit 30 (the power supply unit 30 mounted in the slot 201) to the power supply unit 30. The digital camera 100 can be connected to either the battery 300 or the AC adapter 203. Both the battery 300 and the AC adapter 203 can communicate with the power control unit 80. Therefore, the power control unit 80 can determine the battery type by communicating with the power supply unit 30.

[0051] When a command is transmitted from the digital camera 100 in step S304, the system control unit 50 repeatedly switches the signal level of the communication line between the power control unit 80 and the power supply unit 30 between the L level and the H level. When the transmission of the command is completed, the system control unit 50 returns the current signal level to the signal level before the transmission of the command. Such processing is also performed in steps S312 and S313 described later.

[0052] In step S305, the system control unit 50 acquires the battery type information from the power supply unit 30. The system control unit 50 holds a variable Type indicating the battery type in the RAM of the system memory 52.

[0053] In step S306, the system control unit 50 refers to the variable Type to determine whether the power supply unit 30 (the power supply unit 30 mounted on 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 the battery 300, the process proceeds to step S307. If it is determined that the power supply unit 30 is the AC adapter 203, the process proceeds to step S309.

[0054] In step S307, the system control unit 50 attempts to authenticate the battery 300 to determine whether the battery 300 is an authenticated battery. If it is determined that the battery 300 is not an authenticated battery, control such as "displaying guidance on the display unit 28 notifying that the battery 300 is not an authenticated battery and asking the user whether to use the battery" is performed.

[0055] In step S308, the system control unit 50 executes the process of starting up 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. When the power supply unit 30 is the battery 300, the startup process is executed using the power from the battery 300. As a result, the system control unit 50 enables functions such as taking or playing back an image (still image or moving image). When the process of step S308 ends, the startup process of the digital camera 100 is completed. Therefore, the time required from the start of the process of this flowchart to the end of the process of step S308 is the startup time of the digital camera 100.

[0056] 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, in the case of an AC adapter that does not support USB PD, the output voltage cannot be changed, and for example, a predetermined voltage is supplied from the AC adapter. The predetermined voltage does not have to be 10V and is set to a voltage at which the digital camera 100 can operate.

[0057] In step S310, the system control unit 50 determines the voltage required by the digital camera 100 that is executing the program of the process in FIG. 4 (hereinafter referred to as the "required voltage") based on the information read from the non-volatile memory 56. The required voltage of the digital camera 100 according to Embodiment 1 is 10V. Therefore, here it is determined that the required voltage is 10V, and since it is necessary to request an output voltage of 10V from the AC adapter 203, the process proceeds to step S311. Also, depending on the model of the digital camera, the required voltage may be 7.5V. In that case, since power at a voltage of 7.5V, which is the initial voltage, is already being supplied from the AC adapter 203 and negotiation is not necessary, the process proceeds to step S308.

[0058] 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 at the 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 at the H level at startup), the process proceeds to step S308.

[0059] In step S312, the system control unit 50 requests the AC adapter 203 to supply 10V power to the digital camera 100 by sending a command (hereinafter referred to as the "10V command") to the AC adapter 203 to instruct it to switch the output voltage from the AC adapter 203 to 10V. In this way, when it is determined in step S311 that the execution flag is set to On (the signal level of the communication line at the startup of the digital camera 100 is the L level), the system control unit 50 sends the 10V command. By doing this, the system control unit 50 requests the AC adapter 203 to supply 10V power to the digital camera 100. On the other hand, when it is determined in step S311 that the execution flag is set to Off (the signal level of the communication line at the startup of the digital camera 100 is the H level), the system control unit 50 does not send the 10V command. That is, 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 is supplied with the power of the voltage that was recently (previously) requested from the AC adapter 203 (the power of the voltage that was recently supplied from the AC adapter 203 to the digital camera 100) from the AC adapter 203.

[0060] In step S313, the system control unit 50 sends a response command to the AC adapter 203. The response command is a command that requests the AC adapter 203 to respond with the output voltage of the power output from the AC adapter 203 to the digital camera 100. Also, the system control unit 50 acquires the information on the output voltage from the AC adapter 203.

[0061] In response to the commands sent in steps S312 and S313, the control unit 251 of the AC adapter 203 performs the processing from step S410 and subsequent steps of the flowchart in FIG. 6 described later.

[0062] In step S314, the system control unit 50 reads the information on the output voltage of the AC adapter 203 obtained in step S313. Then, the system control unit 50 determines whether the output voltage is 10V. If it is determined that the output voltage is 10V, the process proceeds to step S315. If it is determined that the output voltage is not 10V, the processes of steps S313 and S314 are repeated until it is determined in step S314 that the output voltage is 10V.

[0063] In step S315, the system control unit 50 effectively sets the built-in pull-up of the communication line between the power control unit 80 and the AC adapter 203. As a result, the signal level of the communication line between the power control unit 80 and the power supply unit 30 is set to level H. Thereafter, when communication with the AC adapter 203 is required, the system control unit 50 invalidates the built-in pull-up in the same manner as in step S303, and after the communication is completed, the built-in pull-up is effectively set again in the same manner as in step S315.

[0064] Note that when the AC adapter 203 is removed from the slot 201, the power supply to the digital camera 100 is cut off, so the communication line between the power control unit 80 and the power supply unit 30 cannot be maintained at the H level, and the signal level becomes the L level. Therefore, after replacing the battery 300 mounted in the slot 201 with the AC adapter 203, at the first startup when the power is turned on, in step S301, it is determined that the signal level of the communication line is the L level.

[0065] FIG. 5 is a flowchart excerpting the processing at the end of the digital camera 100 among the programs executed by the system control unit 50. The processing at the end in FIG. 5 includes the processing performed when the user instructs to turn off the power of the digital camera 100 by operating the power switch 72. Further, the processing at the end in FIG. 5 includes the processing performed when the digital camera 100 shifts to the auto power-off state. When no operation is performed on the digital camera 100 for a certain period, the system control unit 50 shifts the digital camera 100 to the auto power-off state. Further, in the auto power-off state, when there is any operation on the digital camera 100, the system control unit 50 performs the startup processing in FIG. 4.

[0066] In step S350, the system control unit 50 performs the processing of stopping the power of the digital camera 100. Specifically, the system control unit 50 controls the power control unit 80 to stop the supply of power to each block of the digital camera 100. Thereby, the system control unit 50 makes the functions such as shooting or playing back an image (still image or moving image) inoperable.

[0067] In step S351, the system control unit 50 controls the power control unit 80 in the same manner as in step S304, and acquires the battery type information by communicating with the power supply unit 30.

[0068] In step S352, the system control unit 50 determines whether the power supply unit 30 (the power supply unit 30 mounted in the slot 201) is the battery 300 or the AC adapter 203 based on the battery type information. If it is determined that the power supply unit 30 is the battery 300, the process proceeds to step S353. If it is determined that the power supply unit 30 is the AC adapter 203 the processing of this flowchart ends. Therefore, if it is determined that the power supply unit 30 is the AC adapter 203, the system control unit 50 controls to maintain the signal level of the communication line between the power control unit 80 and the power supply unit 30 at the current level even after the power of the digital camera 100 is stopped.

[0069] In step S353, the system control unit 50 controls the power control unit 80 to instruct the power supply unit 30 to transition to the Sleep state. In this case, the power supply unit 30 sets the controller in the battery 300 to transition to the low power consumption mode to reduce the power consumption of the battery 300.

[0070] In step S354, the system control unit 50 sets the communication line between the power control unit 80 and the power supply unit 30 to output the L level.

[0071] Referring to the flowchart of FIG. 6, the processing executed by the control unit 251 in the AC adapter 203 will be described. When the USB connector 204 of the AC adapter 203 is connected to the PD power adapter 205, power is supplied from the PD power adapter 205. The control unit 251 is activated by the power from the PD power adapter 205 by being connected to the PD power adapter 205.

[0072] 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. Then, the control unit 251 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 a voltage of 15V is output from the PD power adapter 205.

[0073] In step S401, the control unit 251 controls the output voltage detection unit 260 to read the output voltage from the AC adapter 203 to the digital camera 100. Here, as described above, the input voltage of 15V from the PD power adapter 205 is converted to half by the switched capacitor 253, and the output voltage becomes 7.5V.

[0074] In step S402, the control unit 251 determines whether the output voltage obtained in step S401 is 7.5V. If it is determined that the output voltage is 7.5V, the process proceeds to step S403. If it is determined that the output voltage is not 7.5V, the processes of steps S401 and S402 are repeated.

[0075] In step S403, the control unit 251 sets the FET 256 to on. As a result, since the power control unit 80 of the digital camera 100 detects that the power required for starting the digital camera 100 is being supplied, the system control unit 50 executes the processes of the flowchart in FIG. 4. Thereby, power of 7.5V is supplied to the digital camera 100 as the initial voltage.

[0076] In step S404, the control unit 251 monitors the output of the USB connection detection unit 259 and determines whether disconnection of the USB connection (disconnection of the connection between the USB connector 204 and the PD power adapter 205) has occurred. If disconnection of the USB connection is detected, the process proceeds to step S420. If it is determined that the USB connection is continued, the process proceeds to step S405.

[0077] 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 the H level, it is determined that communication between the digital camera 100 and the AC adapter 203 is not being performed, and the process returns to step S404. On the other hand, when the signal level of the communication line 263 is the L level, it is considered that "communication is being performed" or "the AC adapter 203 has been removed from the slot 201". Therefore, when it is determined that the signal level of the communication line 263 is the L level, the process proceeds to step S406 in order to determine which event has occurred.

[0078] In step S406, the control unit 251 measures, using the non - attachment determination timer, the time (continuous time) during which the signal level of the communication line 263 remains at the L level. Here, if the timer is measuring the continuous time, the process proceeds to step S407. If the timer has finished measuring the continuous time, it is determined that the AC adapter 203 has been removed from the slot 201, and the process proceeds to step S418. In Embodiment 1, this timer measures the time during which the signal level of the communication line 263 remains at the L level for a predetermined time (for example, 500 ms), and then ends the measurement.

[0079] In step S407, 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 at the H level, since the signal level has become the H level while the timer is running, it is determined that communication is being performed between the digital camera 100 and the AC adapter 203, and the process proceeds to step S408. If it is determined that the signal level of the communication line 263 remains at the L level, the process returns to step S406.

[0080] In step S408, the control unit 251 receives the data (including commands) transmitted from the power control unit 80 to the AC adapter 203.

[0081] In step S409, the control unit 251 stops the non - attachment determination timer and clears (sets to 0) the count value of the continuous time.

[0082] In step S410, the control unit 251 determines whether the command (hereinafter referred to as the "acquired command") acquired in step S408 is a type determination command (a command for requesting the type determination of the power supply unit 30). If it is determined that the acquired command is a type determination command, the process proceeds to step S411. If it is determined that the acquired command is not a type determination command, the process proceeds to step S413.

[0083] In step S411, the control unit 251 reads out the type information from the non-volatile memory 264. The type information includes information on whether the power supply unit 30 is the battery 300 or the AC adapter 203, information on whether it supports USB PD, and information determined by the AC adapter 203, etc.

[0084] In step S412, the control unit 251 transmits the type information obtained in step S411 to the power control unit 80.

[0085] In step S413, the control unit 251 determines whether the acquisition command is a 10V command (a command requesting the output of a 10V voltage). If it is determined that the acquisition command is a 10V command, the process proceeds to step S414. If it is determined that the acquisition command is not a 10V command, the process proceeds to step S415.

[0086] 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.

[0087] In step S415, the control unit 251 determines whether the acquisition command is a command that requests an answer for the output voltage (hereinafter referred to as the "answer command"). If it is determined that the acquisition command is an answer command, the process proceeds to step S416. If it is determined that the acquisition command is not an answer command, the process returns to step S404. In step S416, the control unit 251 controls the output voltage detection unit 260 to detect the output voltage.

[0088] In step S417, the control unit 251 transmits the output voltage information (information on the value of the output voltage) obtained in step S416 to the power control unit 80.

[0089] In step S417, the control unit 251 transmits the output voltage information (information on the value of the output voltage) obtained in step S416 to the power control unit 80.

[0090] In step S418, the control unit 251 communicates with the PD controller 252 to determine the current negotiation voltage. Here, the negotiation voltage is the voltage that the PD controller 252 requests from the PD power adapter 205. If it is determined that the negotiation voltage is 20V, the process proceeds to step S419. If it is not determined that the negotiation voltage is 20V, the process returns to step S404.

[0091] In step S419, the control unit 251 controls the PD controller 252 to start communicating with the PD power adapter 205 and requests to supply 15V of power (conduct 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 may proceed to step S419.

[0092] In step S420, the control unit 251 requests the digital camera 100 to execute the process of the flowchart in FIG. 5 by sending a stop request for the camera function to the power control unit 80. When the PD power adapter 205 is disconnected from the USB connector 204, power from the capacitor 255 is output to the digital camera 100 from the AC adapter 203. Therefore, before the output from the capacitor 255 decreases and the power supply from the AC adapter 203 stops, the system control unit 50 performs a power-off process for the digital camera 100. The system control unit 50 controls the power control unit 80 to stop supplying power to each block of the digital camera 100. After that, when the power supply from the AC adapter 203 is stopped, the level of the communication line with the power supply unit 30 cannot be maintained at the H level and becomes the L level, resulting in a power-off state.

[0093] According to Embodiment 1, when the digital camera 100 is powered on, if the signal level of the communication line with the AC adapter 203 is at the L level, in principle, the digital camera 100 requests the AC adapter 203 to supply the power of the voltage (requested voltage) required by the digital camera 100, and determines the supply voltage from the AC adapter 203. On the other hand, when the digital camera 100 is powered on and the signal level of the communication line with the AC adapter 203 is at the H level, the digital camera 100 does not request the supply of the power of the requested voltage. Therefore, the digital camera 100 receives the supply of the power of the voltage that the digital camera 100 requested most recently (before power-off) from the AC adapter 203. In addition, the digital camera 100 controls to maintain the signal level of the communication line with the AC adapter 203 even after power-off when the power is turned off. Therefore, when the power is turned off while the digital camera 100 is receiving 10V, which is the voltage required by the digital camera 100, from the AC adapter 203, the signal level of the communication line with the AC adapter 203 is maintained at the H level. In this state, when the power of the digital camera 100 is turned on again, since the signal level of the communication line with the AC adapter 203 is maintained at the H level, the AC adapter 203 does not perform power negotiation.

[0094] Therefore, the influence of the processing time of power negotiation on the startup time of the digital camera 100 can be reduced. Also, when power negotiation needs to be performed since power negotiation is performed, the AC adapter 203 can provide appropriate power to the digital camera 100.

[0095] As described above, the present invention has been described in detail based on its preferred embodiments. However, the present invention is not limited to these specific embodiments, and various forms within the scope not departing from the gist of this invention are also included in the present invention. Some of the above-described embodiments may be combined as appropriate.

[0096] Also, in the above, “if A is greater than or equal to B, proceed to step S1; if A is less than B, proceed to step S2” may be read as “if A is greater 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 B, proceed to step S1; if A is less than or equal to B, proceed to step S2” may be read as “if A is greater than or equal to B, proceed to step S1; if A is less than B, proceed to step S2”. Therefore, as long as there is no contradiction, “A or more” may be read as “greater than (higher; longer; more) than A”, and “A or less” may be read as “less than (lower; shorter; less) than A”. And “greater than (higher; longer; more) than A” may be read as “A or more”, and “less than (lower; shorter; less) than A” may be read as “A or less”.

[0097] Note that each functional part of each of the above embodiments (each modification) may be individual hardware, or may not be. The functions of two or more functional parts may be realized by common hardware. Each of the multiple functions of one functional part may be realized by individual hardware. Two or more functions of one functional part may be realized by common hardware. Also, each functional part may be realized by hardware such as an ASIC, FPGA, or DSP, or may not be. For example, the device may have a processor and a memory (storage medium) in which a control program is stored. And the functions of at least some of the functional parts of the device may be realized by the processor reading and executing the control program from the memory.

[0098] (Other Embodiments) The present invention can also be realized by supplying a program that realizes one or more functions of the above embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (for example, an ASIC) that realizes one or more functions.

[0099] The disclosure of the above embodiments includes the following configurations, methods, programs, and media. (Configuration 1) An electronic device to which a predetermined accessory for supplying power is removably connected, means for communicating with the predetermined accessory via a communication line, and when the signal level of the communication line is at a first level at the time of starting up the electronic device, requesting the predetermined accessory to supply power of a first voltage, and when the signal level of the communication line is at a second level, not requesting the predetermined accessory to supply power of the first voltage; setting means for setting the 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; control means for controlling to maintain the signal level of the communication line at the time of stopping the power supply of the electronic device after the power supply of the electronic device is stopped; An electronic device characterized by comprising the above. (Configuration 2) having a power control unit that receives the voltage output from the predetermined accessory, when the power control unit requests the first voltage from the predetermined accessory, the power control unit receives the first voltage from the predetermined accessory, and when not requesting the first voltage from the predetermined accessory, the power control unit receives a second voltage lower than the first voltage from the predetermined accessory from the predetermined accessory. The electronic device according to Configuration 1, characterized by the above. (Configuration 3) The second voltage is a predetermined voltage supplied from the predetermined accessory when there is no request for the first voltage from the electronic device. The electronic device according to Configuration 2, characterized by the above. (Configuration 4) When the first voltage is requested by the communication means, the predetermined accessory performs a process for changing the output voltage from the predetermined accessory from the second voltage to the first voltage. The electronic device according to Configuration 2 or 3, characterized in that... (Configuration 5) The predetermined accessory receives power from a power supply device according to the USB PD standard, generates an output voltage to the electronic device from the input voltage from the power supply device, and outputs it to the electronic device. The process for the change is a power negotiation process of USB PD. The electronic device according to Configuration 4, characterized in that... (Configuration 6) The electronic device further has a slot where the predetermined accessory and a battery can be attached. When the predetermined accessory is attached to the slot, the control means controls to maintain the signal level of the communication line at the time of power-off of the electronic device after the power of the electronic device is stopped. When the battery is attached to the slot, when the power of the electronic device is stopped, the signal level of the communication line is set to the first level. The electronic device according to any one of Configurations 1 to 5, characterized in that... (Configuration 7) The first level is the L level. The second level is the H level. The electronic device according to any one of Configurations 1 to 6, characterized in that... (Configuration 8) When the predetermined accessory is removed from the electronic device, the signal level of the communication line becomes the first level. The electronic device according to Configuration 7, characterized in that... (Configuration 9) When the communication means receives a power supply stop request from the predetermined accessory, the control means performs a power-off process 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. The electronic device according to Configuration 7, characterized in that... (Configuration 10) When the power supply from the predetermined accessory is stopped, the signal level of the communication line becomes the first level. The electronic device according to configuration 7, characterized by the above. (Configuration 11) An electronic device to which a predetermined accessory for supplying power is removably connected, A system having the predetermined accessory, The electronic device is means for communicating with the predetermined accessory via a communication line. When the signal level of the communication line is at a first level at the time of startup of the electronic device, it requests the predetermined accessory to supply power at a first voltage. When the signal level of the communication line is at a second level, it does not request the predetermined A first communication means that does not request the accessory to supply power at the first voltage, Setting means for setting the signal level of the communication line to the second level when the first communication means requests the predetermined accessory to supply power at the first voltage, After the power supply of the electronic device is stopped, first control means for controlling to maintain the signal level of the communication line at the time of stopping the power supply of the electronic device, The predetermined accessory Receives an input voltage from a power supply device, generates an output voltage from the input voltage, and supplies it to the electronic device, Second control means for controlling the supply means to supply an output voltage at a second voltage lower than the first voltage when there is no request from the first communication means, and to supply an output voltage at the first voltage when there is a request from the first communication means, The second control means prevents a process of changing the output voltage by the supply means from being performed when the signal level of the communication line is maintained at the second level A system characterized by the above. (Configuration 12) When there is no such request from the first communication means, the supply means requests the power supply device for a third voltage corresponding to the second voltage, generates the second voltage from the third voltage which is the input voltage, supplies it to the electronic device, and when performing the process of changing the output voltage to the first voltage, requests the power supply device for a fourth voltage corresponding to the first voltage, and generates the first voltage from the fourth voltage which is the input voltage and supplies it to the electronic device. The system according to Configuration 11, characterized by the above. (Configuration 13) The predetermined accessory receives power from the power supply device according to the USB PD standard. The system according to Configuration 11 or 12, characterized by the above. (Method) A control method for an electronic device to which a predetermined accessory for supplying power is removably connected, A step of communicating with the predetermined accessory via a communication line. When the signal level of the communication line is at a first level at the startup of the electronic device, request the predetermined accessory to supply power of a first voltage. When the signal level of the communication line is at a second level, do not request the predetermined accessory to supply power of the first voltage. A communication step, A setting step of setting the signal level of the communication line to the second level when requesting the predetermined accessory to supply power of the first voltage in the communication step, A control step of controlling to maintain the signal level of the communication line at the time of stopping the power supply of the electronic device after the power supply of the electronic device is stopped, A control method characterized by having the above. (Program) A program for causing a computer to function as each means of the electronic device according to any one of Configurations 1 to 10. (Medium) A computer-readable storage medium storing a program for causing a computer to function as each means of the electronic device according to any one of Configurations 1 to 10.

Description of Signs

[0100] 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 requesting the predetermined accessory to supply power of a first voltage when a signal level of the communication line is at a first level when the electronic device is started up, and not requesting the predetermined accessory to supply power of the first voltage when the signal level of the communication line is at a second level; a 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 control means for controlling, after the power supply of the electronic device is stopped, to maintain a signal level of the communication line at the time when the power supply of the electronic device was stopped; a power supply control means for receiving a voltage output from the predetermined accessory; having The power supply control means receiving the first voltage from the predetermined accessory when the first voltage is requested from the predetermined accessory by the communication means; when the first voltage is not requested from the predetermined accessory by the communication means, a second voltage lower than the first voltage is received from the predetermined accessory; when the first voltage is requested by the communication means, a process is performed by the predetermined accessory to change an output voltage from the predetermined accessory from the second voltage to the first voltage; The predetermined accessory receives power from a power supply device in accordance with the USB Power Delivery (USB PD) standard, generates an 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 power supply voltage is a process for power negotiation of the USB PD.

1. An electronic device comprising:

2. The second voltage is a predetermined voltage supplied from the predetermined accessory when there is no request for the first voltage from the electronic device.

2. The electronic device according to claim 1 .

3. The device further has a slot into which the predetermined accessory and the battery can be attached, the control means, when the predetermined accessory is attached to the slot, controls the communication line so as to maintain a signal level at the time when the power supply of the electronic device is stopped after the power supply of the electronic device is stopped, and when the battery is attached to the slot, the control means sets the signal level of the communication line to the first level when the power supply of the electronic device is stopped.

2. The electronic device according to claim 1 .

4. The first level is an L level, The second level is an H level.

2. The electronic device according to claim 1 .

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

5. The electronic device according to claim 4.

6. When the communication means receives a request to stop the power supply from the predetermined accessory, the 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.

5. The electronic device according to claim 4.

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

5. The electronic device according to claim 4.

8. An electronic device to which a predetermined accessory that supplies power is removably connected; and the predetermined accessory, The electronic device includes: a first communication means for communicating with the predetermined accessory via a communication line, the first communication means requesting the predetermined accessory to supply power of a first voltage when a signal level of the communication line is at a first level when the electronic device is started up, and not requesting the predetermined accessory to supply power of the first voltage when the signal level of the communication line is at a second level; a setting means for setting a signal level of the communication line to the second level when the first communication means requests the predetermined accessory to supply power of the first voltage; a first control means for controlling, after the power supply of the electronic device is stopped, to maintain a signal level of the communication line at the time when the power supply of the electronic device was stopped; a power supply control means for receiving a voltage output from the predetermined accessory; having The power supply control means receiving the first voltage from the predetermined accessory when the first voltage is requested from the predetermined accessory; receiving a second voltage lower than the first voltage from the predetermined accessory when the first voltage is not required from the predetermined accessory; The predetermined accessory is A supplying means for receiving an input voltage from a power supplying device in accordance with the USB Power Delivery (USB PD) standard, generating an output voltage from the input voltage, and supplying the output voltage to the electronic device; supplying an output voltage of the second voltage when there is no request from the first communication means, and supplying an output voltage of the first voltage when there is a request from the first communication means. a second control means for controlling the supply means in such a manner that having The second control means controls the supply means so that, when the first voltage is requested from the first communication means, a process of power negotiation of USB PD is performed to change the output voltage from the second voltage to the first voltage. A system characterized by:

9. When there is no request from the first communication means, the supply means requests a third voltage corresponding to the second voltage from the power supply device, generates the second voltage from the third voltage which is the input voltage, and supplies the second voltage to the electronic device, and when performing a process of USB PD power negotiation for changing the output voltage to the first voltage, requests a fourth voltage corresponding to the first voltage from the power supply device, generates the first voltage from the fourth voltage which is the input voltage, and supplies the first voltage to the electronic device.

9. The system of claim 8.

10. The supply means includes a switched capacitor that converts the input voltage to a fraction of an integer to generate the output voltage.

10. The system of claim 9.

11. The switched capacitor converts the input voltage to 1 / 2 and outputs the converted voltage, the first voltage is 10V; the second voltage is 7.5V; the third voltage is 15V; The fourth voltage is 20V. The system of claim 10.

12. A method for controlling an electronic device to which a predetermined accessory that supplies power is removably connected, comprising: a step of communicating 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 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 control step of performing control so as to maintain a 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 power supply control step of receiving a voltage output from the predetermined accessory; having In the power supply control step, receiving the first voltage from the predetermined accessory when the first voltage is requested from the predetermined accessory in the communication step; receiving a second voltage lower than the first voltage from the predetermined accessory when the first voltage is not requested from the predetermined accessory in the communication step; when the first voltage is requested in the communication step, a process is performed by the predetermined accessory to change an output voltage from the predetermined accessory from the second voltage to the first voltage; The predetermined accessory receives power from a power supply device in accordance with the USB Power Delivery (USB PD) standard, and outputs an output voltage to the electronic device from an input voltage from the power supply device. generating an output voltage and outputting it to the electronic device; The process for changing the power supply voltage is a process for power negotiation of the USB PD. A control method comprising:

13. 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 7.

14. 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 7.

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