Electronic device and method

An electronic device includes a control unit and a communication unit that is capable of communicating with a power supply device. The control unit determines whether or not a predetermined message relating to an authentication communication is received from the power supply device via the communication unit, and controls the electronic device to limit operation of the electronic device in a case where the predetermined message is received from the power supply device via the communication unit.

BACKGROUND

Field of the Disclosure

Aspects of the disclosure generally relate to an electronic device capable of operating using power supplied from a power supply device, and to a method of controlling the electronic device.

Description of the Related Art

Universal Serial Bus (USB) Type-C standard and USB Power Delivery (PD) standard are known as standards relating to USB. A USB interface compliant with the USB PD standard can supply power at a maximum of 100 W.

Japanese Patent Laid-Open No. 2018-097643 discloses a power supply apparatus that performs an authentication communication to authenticate whether or not a USB cable is a predetermined cable.

When an electronic device that does not support the authentication communication such as that disclosed in Japanese Patent Laid-Open No. 2018-097643 is connected to a power supply device such as that disclosed in Japanese Patent Laid-Open No. 2018-097643, it is assumed that power supplied to the electronic device from the power supply device will be limited. In such a case, the electronic device may not be able to start or continue operating as desired by a user.

SUMMARY

According to various embodiments, there is provided an electronic device that is capable of limiting power supplied from a power supply device, and a method that controls the electronic device.

According to various embodiments, there is provided an electronic device that includes a communication unit that is capable of communicating with a power supply device; and a control unit that determines whether or not a predetermined message relating to an authentication communication is received from the power supply device via the communication unit, and controls the electronic device to limit operation of the electronic device in a case where the predetermined message is received from the power supply device via the communication unit.

According to various embodiments, there is provided a method that includes determining whether or not a predetermined message relating to an authentication communication is received from a power supply device via a communication unit of an electronic device; and controlling the electronic device to limit operation of the electronic device in a case where the predetermined message is received from the power supply device via the communication unit of the electronic device.

Further aspects of the disclosure will become apparent from the following description of exemplary embodiments.

DESCRIPTION OF THE EMBODIMENTS

Exemplary embodiments, features, and aspects of the disclosure will be described below with reference to the drawings. However, aspects of the disclosure are not limited to the following embodiments.

[First Embodiment]FIG.1is a diagram illustrating an example of the external appearance of a power supply system according to a first embodiment. As illustrated inFIG.1, the power supply system includes an electronic device100and a power supply device300. Both the electronic device100and the power supply device300are electronic devices compliant with the USB PD standard and the USB Type-C standard.

The electronic device100includes an image capture unit102, an operation unit104, and a connection unit110. The electronic device100is an electronic device capable of operating using power supplied from the connection unit110or a battery111. The electronic device100can operate as a sink according to the USB PD standard, but cannot operate as a responder according to the USB Type-C Authentication standard (called “C-Auth standard” hereinafter). The electronic device100is furthermore an electronic device that can operate as, for example, a digital camera, a digital video camera, a personal computer, a tablet computer, a media player, a PDA, a mobile phone, a smartphone, a game console, a robot, or a drone.

The power supply device300includes a USB cable200, and supplies power to a power receiving device connected to a USB Type-C plug201provided at an end of the USB cable200. Note that the power supply device300is an electronic device that can operate as a source according to the USB PD standard, and can operate as an initiator according to the C-Auth standard. The power supply device300can operate as, for example, a USB-AC adapter, a mobile battery, a personal computer, or a tablet computer.

Elements of the electronic device100will be described next with reference toFIG.2.

A main control unit101is configured to control the elements of the electronic device100. The main control unit101includes, for example, a hardware processor (a CPU or the like) that controls the elements of the electronic device100. The hardware processor of the main control unit101controls the elements of the electronic device100by executing programs stored in memory107.

The image capture unit102includes a lens unit, an image sensor, related circuitry, and the like, and generates image data. Operation of the image capture unit102are controlled by the main control unit101. The image data generated by the image capture unit102is stored in memory106. The main control unit101performs a predetermined image process on the image data stored in the memory106and generates image data for display, image data for recording, and evaluation values. The image data for display is displayed in a display unit105. The image data for recording is recorded into a recording medium103.

The recording medium103is a memory card or a hard disk, for example. The recording medium103may be removable from the electronic device100, or may be built into the electronic device100.

The operation unit104is a collective name for input devices (buttons, switches, dials, a touch panel, or the like) provided for a user to input various types of instructions to the electronic device100. Operations made using the operation unit104are detected by the main control unit101, a sub control unit108, or both. For example, the operation unit104includes a release switch, a moving image recording switch, a shooting mode selection dial for selecting a shooting mode, a menu button, a directional key, an OK key, or the like. The release switch is a switch for recording a still image, and the main control unit101and the sub control unit108recognize the release switch being in a half-pressed state as a shooting preparation instruction, and the release switch being in a fully-pressed state as a shooting start instruction. Additionally, the main control unit101and the sub control unit108recognize the moving image recording switch being pressed while in a shooting standby state as a moving image recording start instruction, and recognize the moving image recording switch being pressed while recording a moving image as a recording stop instruction. Note that the functions assigned to a given input device may be variable. Additionally, the input devices may include a software buttons or keys which use a touch screen.

The display unit105displays the image data generated by the image capture unit102, information relating to settings or the status of the electronic device100, menu screens, or the like. The display unit105may be a display apparatus connected to the electronic device100.

The memory106is used as buffer memory that temporarily holds the image data generated by the image capture unit102, video memory for the display unit105, work memory for the main control unit101, or the like. The memory107stores programs or the like that can be executed by the hardware processor of the main control unit101.

The sub control unit108is configured to control the elements of the electronic device100. The sub control unit108includes, for example, a hardware processor (a CPU or the like) that controls the elements of the electronic device100, and memory storing programs that can be executed by the hardware processor. The sub control unit108can communicate with the main control unit101and can operate with a lower power consumption than the main control unit101. The sub control unit108operates as a control unit that controls a power reception control unit109.

The power reception control unit109supplies, to the elements of the electronic device100, power which has been received through the connection unit110. The power reception control unit109also controls charging of the battery111using power received through the connection unit110. The power reception control unit109performs communication compliant with the USB PD standard (PD communication) with the power supply device300connected to the connection unit110.

The connection unit110can operate as a USB interface. The electronic device100can receive power supplied from the power supply device300connected to the connection unit110. Note that the power supply device300is capable of data communication, and the electronic device100may perform data communication with the power supply device300. Note also that in the first embodiment, the connection unit110includes a USB Type-C receptacle and a USB device controller. The connection unit110may include an interface aside from a USB interface.

The battery111operates as a power source of the electronic device100. The battery111is a battery which can be removed from the electronic device100, and is a rechargeable battery. The charging of the battery111is controlled by the power reception control unit109.

A power source control unit112controls the power supply from the battery111or the connection unit110to the other elements of the electronic device100under the control of the main control unit101or the sub control unit108.

Elements of the power supply device300will be described next with reference toFIG.3.

InFIG.3, the flow of control signals is indicated by thin lines, and the flow of power is indicated by bold lines. The power supply device300can operate as a power supply side device (a source) according to the USB PD standard. The power supply device300can also operate as an initiator according to the C-Auth standard.

A control unit301is configured to control the elements of the power supply device300. The control unit301includes, for example, a hardware processor (a CPU or the like) that controls the elements of the power supply device300, and memory storing programs that can be executed by the hardware processor.

A connection unit302can operate as a USB interface, and the USB cable200is connected thereto. The USB Type-C plug201is provided on one end of the USB cable200. The connection unit302includes a USB host controller.

An information obtaining unit303performs communication compliant with the USB PD standard (PD communication) with the electronic device100connected to the power supply device300by the USB cable200. Furthermore, the information obtaining unit303performs communication compliant with the C-Auth standard (authentication communication or the like) with the electronic device100.

A connection unit304is connected to a power source such as an AC outlet, a mobile battery, or the like. A power supply control unit305transforms a voltage and current supplied from a power source connected to the connection unit304into predetermined DC voltage and DC current (e.g., 9 V, 3 A). The DC voltage and the DC current which the power supply control unit305can generate are communicated to the electronic device100as power supply capabilities of the power supply device300. The DC voltage and DC current generated by the power supply control unit305are controlled by the control unit301.

An output control unit306is connected to a VBUS terminal of the connection unit302. The output control unit306controls whether to supply the power generated by the power supply control unit305to, or cut that power off from, the VBUS terminal of the connection unit302. The output control unit306furthermore controls a level of power supplied to the electronic device100based on information or a command obtained from the information obtaining unit303.

Elements of the power reception control unit109will be described next with reference toFIG.4.

InFIG.4, the flow of control signals is indicated by thin lines, and the flow of power is indicated by bold lines. Note also thatFIG.4focuses primarily on the flow of power supplied to the VBUS terminal, and does not illustrate the flow of power arising in a case where the electronic device100operates using the battery111.

An information obtaining unit1091is connected to a CC (Configuration Channel) terminal of the connection unit110. The information obtaining unit1091performs PD communication with the power supply device300connected to the connection unit110. The information obtaining unit1091detects that the power supply device300is a source according to the USB PD standard based on a voltage at the CC terminal, and requests the power supply device300supply a specified power through PD communication.

An input control unit1092is connected to the VBUS terminal of the connection unit110. The input control unit1092receives power from the power supply device300through the VBUS terminal. Additionally, under the control of the information obtaining unit1091, the input control unit1092can switch between supplying power to and cutting off power from a power supply control unit1093.

The power supply control unit1093transforms power supplied through the input control unit1092into power suited to the power source control unit112and a charging control unit1094. In a case where, for example, power is supplied at 5 V or 9 V, the power supply control unit1093drops the power down to an appropriate cell voltage. The first embodiment assumes that the battery111is a single-cell lithium-ion battery, and that CCCV charging is performed, in which after charging the cell voltage to 4.2 V using a constant current, the battery111is charged at 4.2 V until fully charged. The power supply control unit1093may be configured to be capable of stepping up or stepping down in accordance with the number of cells in the battery111, the voltage supplied, and so on. In a case where the battery111is not attached, the power supply control unit1093transforms power supplied via the input control unit1092to a voltage having the highest efficiency (e.g., 3.7 V) in the power source control unit112.

The power supply control unit1093can also limit the supplied current in accordance with an instruction from the sub control unit108based on capability information of the power supply device300, obtained by the information obtaining unit1091. For example, if 27 W (9 V, 3 A) of power is supplied from the power supply device300, the power supply control unit1093can limit the current flowing so as not to exceed 3.0 A.

The charging control unit1094can charge the battery111connected to a connection unit1095with power supplied via the power supply control unit1093. The charging control unit1094charges the battery111using CCCV charging, for example.

The connection unit1095holds the battery111in a removable manner, for example. The connection unit1095includes terminals that contact terminals of the battery111which is held, such as a power supply terminal, a GND terminal, and a thermistor terminal. The thermistor terminal is a terminal for a temperature sensor built into the battery111.

A voltage monitoring unit1096notifies the sub control unit108of a voltage at the VBUS terminal. The sub control unit108monitors whether or not the voltage notified by the voltage monitoring unit1096is anomalous. For example, if the power requested of the power supply device300is 27 W (9V, 3 A), the sub control unit108monitors whether the voltage notified by the voltage monitoring unit1096is too high (e.g., 15 V) or too low. Then, upon detecting an anomalous voltage of the VBUS terminal, the sub control unit108stops, the input control unit1092and requests the power supply device300to stop power supply through the information obtaining unit1091, for example.

Note thatFIG.4illustrates the voltage monitoring unit1096monitoring the voltage between the input control unit1092and the power supply control unit1093. However, the voltage at another location may be monitored, such as monitoring the voltage between the connection unit110and the connection unit1095.

A temperature monitoring unit1097notifies the sub control unit108of a temperature in the vicinity of the connection unit110. The sub control unit108monitors whether or not the temperature monitoring unit1097has detected an anomalous temperature. For example, in a case where the temperature monitoring unit1097makes a notification of a temperature exceeding a predetermined threshold, the sub control unit108stops the input control unit1092and requests the power supply device300to stop power supply through the information obtaining unit1091, for example.

A power reception control process according to the first embodiment will be described next with reference to the flowchart inFIG.5.

In step S501, the sub control unit108determines whether or not the power supply device300has been connected to the connection unit110via USB. This determination process may be based on the detection of the VBUS voltage by the voltage monitoring unit1096, or may be based on the detection of the voltage at the CC terminal by the information obtaining unit1091. In a case where the power supply device300is determined to be connected to the connection unit110via USB, the sub control unit108performs the process of step S502.

In step S502, the sub control unit108determines whether or not the power supply device300is a source according to the USB PD standard. In a case where the power supply device300is determined to be a source, the sub control unit108performs the process of step S503. In a case where the power supply device300is determined not to be a source, the sub control unit108performs the process of step S507. The sub control unit108can determine that the power supply device300is a source in a case where the information obtaining unit1091receives a message indicating the power supply capabilities of the power supply device300(e.g., Source_Capabilities) from the power supply device300(the information obtaining unit303). On the other hand, the sub control unit108can determine that the power supply device300is not a source in a case where the message has not been received from the power supply device300within a predetermined amount of time after the power supply device300is detected as having been connected.

In step S503, the sub control unit108determines the power to be requested from the power supply device300based on the power supply capabilities of the power supply device300indicated in the message obtained in step S502. The sub control unit108determines the power to be requested from the power supply device300by selecting a power required by the electronic device100to operate from among options for powers which the power supply device300is capable of supplying, for example. If the power supply device300cannot supply the power needed to implement all the functions of the electronic device100, the sub control unit108may limit the operation of the electronic device100to a scope that can be implemented using power from the power supply device300. The sub control unit108causes the information obtaining unit1091to perform PD communication (PD negotiation) for requesting the power which has been determined.

In step S504, the sub control unit108controls the power supply control unit1093so that the power received from the VBUS terminal of the connection unit110is less than or equal to the power determined in step S503.

In a case where the power supply device300receives the request sent in step S503, a message indicating that the request has been received is received by the information obtaining unit1091. The supply of the requested power to the VBUS terminal is also started. The sub control unit108may control the charging control unit1094to charge the battery111using power supplied to the VBUS terminal, cause the electronic device100to perform a predetermined operation by supplying, to the power source control unit112, power supplied to the VBUS terminal, and so on.

In a case where the power supply device300can operate as an initiator according to the C-Auth standard, the power supply device300performs an authentication communication to authenticate whether or not the device is compliant with the USB PD standard. The power supply device300can perform the authentication communication at any desired timing. Accordingly, after controlling the power supply control unit1093in accordance with the requested power in step S504, the sub control unit108monitors whether or not the information obtaining unit1091has received a predetermined message relating to the authentication communication (e.g., Security_Request) from the power supply device300(step S505).

While the information obtaining unit1091is not receiving the predetermined message relating to the authentication communication from the power supply device300, the sub control unit108can use power supplied to the VBUS terminal to operate the electronic device100and charge the battery111.

In step S505, upon detecting that the information obtaining unit1091has received the predetermined message relating to the authentication communication from the power supply device300, the sub control unit108performs the process of step S506.

In step S506, the sub control unit108sends a message indicating that the electronic device100does not support the authentication communication (e.g., Not_Supported) to the power supply device300through the information obtaining unit1091. As a result, the power supply device300is notified that the electronic device100does not support the authentication communication. Additionally, the sub control unit108notifies the main control unit101that the predetermined message has been received.

Next, in step S507, the main control unit101limits the operation of the electronic device100on the assumption that the power supply device300will limit or stop power supply. For example, the main control unit101terminates an operation which cannot be continued in a case where power supplied from the power supply device300is limited. For example, if the electronic device100is shooting a moving image, the shooting is stopped, and the moving image data which has been shot is stored in the recording medium103. The main control unit101may perform a process for shutting down the electronic device100. If the operation limitation is complete, the main control unit101sends a notification to the sub control unit108.

In step S508, the sub control unit108causes the input control unit1092to send a message that requests to stop power supply, to the power supply device300. The power supplied from the power supply device300is stopped as a result. If the shutdown process is not performed in step S507, the electronic device100operates using power from the battery111.

In step S509, the sub control unit108controls the power supply control unit1093to support the reception of bus power as defined by the USB 1.1 to 3.2 standards instead of the USB PD standard. The bus power may be power based on the result of an enumeration procedure performed when the USB connection is made, and is, for example, 5 V, 100 mA, 5 V, 500 mA, or the like.

For example, the sub control unit108may determine whether to operate the electronic device100using power supplied to the VBUS terminal or using the battery111based on an operating mode of the electronic device100, whether the battery111is connected to the electronic device100, the voltage of the battery111, or the like. For example, in a case where the battery111is not connected to the electronic device100, or in a case where the voltage of the battery111is low, the electronic device100can be operated using power supplied to the VBUS terminal (bus power). In this case, the sub control unit108may limit the operation of the electronic device100such that the electronic device100can operate with bus power.

As described thus far, according to the first embodiment, in a case where an electronic device100that does not support the authentication communication has received a predetermined message relating to the authentication communication from a power supply device300, the operation of the electronic device100are limited. For example, operation that is undesirable to be unintentionally interrupted (such as data recording operation) can be terminated or limited from being performed. Accordingly, even if the power supply device300limits (including stopping) power supply based on a failure in the authentication communication, the impact on the operation of the electronic device100can be reduced.

[Second Embodiment] A second embodiment will be described next with reference toFIGS.1to6. The first embodiment describes an example in which in a case where the electronic device100receives a predetermined message relating to the authentication communication from the power supply device300, the operation of the electronic device100are limited regardless of the state of the electronic device100. The second embodiment will describe an example in which in a case where the electronic device100receives a predetermined message relating to the authentication communication from the power supply device300, whether or not to limit the operation of the electronic device100(or whether or not to request the power supply device300to limit or stop power supply) is controlled in accordance with an operation state of the electronic device100. Note that the second embodiment will describe parts different from the first embodiment, and will not describe parts that are the same as in the first embodiment.

FIG.6is a flowchart illustrating a power reception control process according to the second embodiment.

The processes of steps S501to S509are the same as the processes described in the first embodiment, and will therefore not be described here. In a case where a message indicating that the authentication communication is not supported (e.g., Not_Supported) has been sent to the power supply device300in step S506, the sub control unit108performs the process of step S601.

In step S601, the sub control unit108determines whether or not the electronic device100is in power on state. This determination process can be performed based on the state of a power switch included in the operation unit104, for example. In a case where the electronic device100is determined to be in power on state, the sub control unit108performs the process of step S602. In a case where the electronic device100is not determined to be in power on state, the sub control unit108repeats the process of step S601.

In a case where the electronic device100is not determined to be in power on state (i.e., in a case where the electronic device100is in power off state), the bus power is used for operations which would not be affected even if power supply is stopped, such as charging the battery111. Accordingly, the sub control unit108maintains the current power reception state without requesting the power supply device300to stop power supply.

In step S602, the sub control unit108determines whether or not the remaining power of the battery111is less than or equal to a predetermined threshold. The predetermined threshold is, for example, the minimum remaining power at which the electronic device100can operate, without limitations, using power from the battery111. In a case where the remaining power of the battery111is not determined to be less than or equal to the predetermined threshold, the sub control unit108maintains the current power reception state without requesting the power supply device300to stop power supply. This is because in a case where the remaining power of the battery111is not determined to be less than or equal to the predetermined threshold, the operation of the electronic device100can be continued using power from the battery111even if power supplied from the power supply device is stopped. Accordingly, the sub control unit108performs the process of step S601again. In a case where the remaining power of the battery111is determined to be less than or equal to the predetermined threshold, the sub control unit108performs the process of step S507.

According to the second embodiment, in a case where a predetermined message relating to the authentication communication is received from the power supply device300, whether or not to limit the operation of the electronic device100(or whether or not to request the power supply device300to limit or stop power supply) can be controlled in accordance with an operation state of the electronic device100. For example, in a case where the electronic device100is in power off state or in a case where the remaining power of the battery111is not less than or equal to a predetermined threshold, the operation of the electronic device100may not be limited and the power supply device300may not be requested to limit or stop the power supply. Accordingly, in the second embodiment, the electronic device100can even more effectively use power supplied from the power supply device300.

[Third Embodiment] The various functions, processes, or methods described in the first or second embodiment can also be achieved by a personal computer, a microcomputer, a Central Processing Unit (CPU), or a microprocessor executing a program. In a third embodiment, described hereinafter, the personal computer, the microcomputer, the Central Processing Unit (CPU), or the microprocessor will be called a “computer X”. Also, in the third embodiment, a program for controlling the computer X and implementing the various functions, processes, or methods described in the first or second embodiment will be called a “program Y”.

The various functions, processes, or methods described in the first or second embodiment are realized by the computer X executing the program Y. In this case, the program Y is supplied to the computer X via a computer-readable storage medium. The computer-readable storage medium according to the third embodiment includes at least one of a hard disk device, a magnetic storage device, an optical storage device, a magneto-optical storage device, a memory card, volatile memory (e.g., random access memory), non-volatile memory (e.g., read only memory), or the like. The computer-readable storage medium according to the third embodiment is a non-transitory storage medium.

While aspects of the disclosure are described with reference to exemplary embodiments, it is to be understood that the aspects of the disclosure are not limited to the exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures.

This application claims the benefit of Japanese Patent Application No. 2020-108997, filed on Jun. 24, 2020, which is hereby incorporated by reference herein in its entirety.