Controller, control method and control program

Abstract

Embodiments of the present disclosure relate to a controller, a control method, and a control program. A controller for providing a DRP port according to the USB Type-C standard. A state manager is coupled to a power manager for controlling the charging and discharging of a battery. A signal transmission module is used to exchange signals with a connection destination via a communication line in a USB cable according to instructions from the state manager. The signal transmission module can indicate to the communication line whether the port is used as a power supply side or a power receiving side. When the port is used as a power supply side, the state manager supplies electric power stored in the battery to the connection destination, and if the battery becomes a "low battery" condition, the state manager stops supplying electric power to the connection destination while maintaining the state of the port being used as a power supply side.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] The disclosure of Japanese Patent Application No. 2018-158424 filed on August 27, 2018 including the specification, drawings and abstract is incorporated herein by reference in its entirety. Background Art

[0003] The present disclosure relates to a controller, for example, for executing a sequence according to a universal serial bus standard to perform power supply and reception operations with respect to a connection destination.

[0004] With the popularization of mobile devices, mobile batteries for supplying electric power to mobile devices and the like have become popular (for example, see Japanese Unexamined Patent Application Publication No. 2017 / 138870, etc.). In the following description, a power storage device that stores electric power supplied from an external power source and supplies the electric power stored in an external device is referred to as a "mobile power bank".

[0005] In the currently commonly used mobile power supplies, the output (power supply) port for supplying power to an external device and the input (power receiving) port for receiving power from an external power supply are provided separately from each other. For example, a USB standard A type interface is used for the power supply port, and a USB micro B type interface is used for the power receiving port. Since the power supply port and the power receiving port are provided independently for each function in this way, for example, even if the cable remains connected after the mobile power supply is charged, the stored electric power will not flow backward.

[0006] As a newer USB standard, the USB Type-C interface is becoming popular (for example, see the "Universal Serial Bus Type-C Cable and Connector Specification" version 1.3 on July 14, 2017). According to the USB Type-C interface, a port having the same shape is used for power supply and power reception. Therefore, a single port supports both power supply and power reception.

[0007] In the USB Type-C standard, a device for supplying electric power (power supply side) is called a "source" or "SRC", and a device for receiving electric power (power receiving side) is called a "sink" or "SNK". In addition, a device corresponding to both power supply and power reception is called a "DRP (Dual Role Power)". By implementing the DRP function, it is possible to reduce costs and space by requiring only one port, which traditionally required two ports respectively (for example, see Japanese Unexamined Patent Application Publication No. 2018-007451).

[0008] With these advantages, when the USB Type-C interface is adopted in mobile devices (such as mobile power banks, smart phones, tablets, personal computers, etc.), the DRP function is expected to be implemented so that the DRP function can support both power supply and power reception at one port. Summary of the invention

[0009] Assume that only a single port of the USB Type-C interface as described above is provided, and a mobile power supply in which the DRP function is implemented is used to power an external device. The inventors of the present application have found that in this configuration, a new problem occurs, which does not occur when power is supplied by using a mobile power supply in which a power supply port and a charging port are separately provided.

[0010] Other objects and novel features will become apparent from the description of this specification and the accompanying drawings.

[0011] According to one embodiment, a controller for providing a port compatible with DRP (Dual Role Power) according to the USB (Universal Serial Bus) Type-C standard, which port can be either a power supply side or a power receiving side, the controller includes: a state manager, coupled to a power manager for controlling the charging and discharging of a battery; a signal transmission module, for exchanging signals with a connection destination via a communication line in a USB cable according to instructions from the state manager, wherein the signal transmission module can indicate to the communication line whether the port is used as a power supply side or a power receiving side, wherein when the port is used as a power supply side, the state manager supplies electric power stored in the battery to the connection destination, and if the battery becomes a "low battery" condition, the state manager stops supplying electric power to the connection destination while maintaining the state of the port being used as a power supply side.

[0012] According to one embodiment, unexpected operation of a mobile power supply implementing a DRP function by a user can be avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic diagram illustrating operations related to a power supply operation of a mobile power source equipped with a DRP function;

[0014] Figure 2 shows an overview of the state transitions of a device responsible for a port role of a DRP according to the USB Type-C standard;

[0015] Figure 3 It is a graphic with Figure 2 A sequence diagram showing the sequence of state transitions;

[0016] Figure 4 is a schematic diagram illustrating an exemplary device configuration of a mobile power source according to a first embodiment;

[0017] Figure 5 is a schematic diagram showing one example of a circuit configuration of a controller according to the first embodiment;

[0018] Figure 6 An overview of state transition of the mobile power supply according to the first embodiment is shown;

[0019] Figure 7 is a sequence diagram illustrating a processing sequence related to power supply and reception operations performed between a mobile power source and a PC according to the first embodiment;

[0020] Figure 8 is a schematic diagram illustrating one example of power supply and reception operations performed between a mobile power source and a PC according to the first embodiment;

[0021] Fig. 9 is a flowchart illustrating a processing procedure related to a power supply operation of a mobile power source according to a first embodiment;

[0022] Fig.10 shows an overview of state transition of a mobile power supply according to a second embodiment;

[0023] Fig.11 is a sequence diagram illustrating a processing sequence when Error Recovery occurs in a power supply and reception operation performed between a mobile power source and a PC according to the first embodiment;

[0024] Fig.12 is a sequence diagram illustrating a processing sequence related to power supply and reception operations performed between a mobile power source and a PC according to the second embodiment;

[0025] Fig.13 is a schematic diagram illustrating one example of power supply and reception operations performed between a mobile power source and a PC according to the second embodiment;

[0026] Fig.14 is a flowchart illustrating a processing procedure related to a power supply operation of a mobile power source according to a second exemplary embodiment;

[0027] Fig.15 is a diagram showing a main part of a state transition of a mobile power source according to a third embodiment;

[0028] Fig.16 is a schematic diagram illustrating an exemplary device configuration of a mobile power source according to a third exemplary embodiment;

[0029] Fig.17 is a schematic diagram illustrating an exemplary device configuration of a mobile power source according to a third exemplary embodiment;

[0030] Fig.18 is a sequence diagram illustrating a processing sequence related to power supply and reception operations performed between a mobile power source and a PC that do not adopt a conversion condition according to a third embodiment;

[0031] Fig.19 is a sequence diagram illustrating a processing sequence related to power supply and reception operations performed between a mobile power source and a PC according to a third embodiment;

[0032] Fig. 20 is a schematic diagram showing one example of the operation of power supply and reception operations performed between a mobile power source and a PC according to the third embodiment; and

[0033] Fig.21 : is a flowchart illustrating a processing procedure related to power supply and reception operations of a mobile power source according to a third embodiment. DETAILED DESCRIPTION

[0034] Several embodiments will be described in detail with reference to the accompanying drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals, and their description will not be repeated.

[0035] A configuration will be described in which only a single port of a USB Type-C interface is provided and power is supplied to an external device using a mobile power supply in which a DRP function is implemented. At this time, it is assumed that the USB Type-C interface and the DRP function are also implemented in an external device connected to the mobile power supply. In the following description, an external device in which the DRP function is implemented is also referred to as a "DRP device".

[0036] The following will describe the power supply-related sequences according to the USB Type-C standard. As mentioned above, the USB Type-C standard defines three modes: source (SRC), sink (SNK), and DRP. These modes are also called port roles. Below, the device responsible for the DRP port role will be mainly described.

[0037] Figure 1 is a schematic diagram showing an exemplary operation related to the power supply operation of the mobile power supply 100 equipped with the DRP function. Figure 1 In the example of FIG. 1 , a laptop personal computer 200 is assumed as a DRP device. Of course, the DRP device is not limited to a laptop personal computer, and any device having a power storage function may be employed.

[0038] refer to Figure 1A. First, the mobile power supply 100 on the power supply side and the PC 200 that desires to receive power are connected via the USB cable 2. Then, the port role of the mobile power supply 100 becomes SRC (specifically, Attached.SRC (a state in which connection (identification) is performed as the power supply side), as described below), and the port role of the PC 200 becomes SNK (specifically, Attached.SNK (a state in which connection (identification) is performed as the power receiving side), as described below). As a result, electric power starts to be supplied from the mobile power supply 100 to the PC 200.

[0039] like Figure 1 As shown in B, it is assumed that the power supply from the mobile power supply 100 to the PC 200 continues, and finally, as shown in FIG. Figure 1 As shown in C, the discharge voltage of the battery is reduced to a state where the mobile power supply 100 cannot operate as a power source nor as a system. This condition is called "battery exhaustion".

[0040] The DRP function is implemented by the control of the system, and cannot be operated as a system when the battery is "depleted", so the DRP function cannot be maintained. In this state, since the DRP toggle operation cannot be performed, the mobile power supply 100 is fixed to the SNK connection waiting state (Unattached.SNK (not connected (not recognized) as the power receiving side) as firmware, as described below) until the "battery is exhausted" is resolved.

[0041] On the other hand, in order to perform the DRP switching operation, the PC 200 detects that the mobile power supply 100 is in the SNK connection waiting state and changes to the SRC. Figure 1 As shown in FIG. 2D , the PC 200 starts to supply power to the mobile power supply 100 . That is, the mobile power supply 100 will draw power from the PC 200 that supplies power.

[0042] In this way, if a single port implementing the DRP function according to the USB Type C standard supports both power supply and power reception, the above-mentioned problem may occur. In other words, the user only expects to stop supplying power to the PC 200 when the mobile power supply 100 becomes "battery exhausted", but the roles of power supply and reception are reversed, making the operation not the operation expected by the user.

[0043] Here, the state transition related to the operation as the above-mentioned problem will be described. Figure 2 is a diagram showing main parts of state transition of a device in charge of a port role of a DRP according to the USB Type-C standard.

[0044] refer to Figure 2, the device responsible for implementing the DRP function has six states: Unattached.SRC (unattached SRC) (ST1), AttachWait.SRC (attached waiting SRC) (ST2), Attached.SRC (attached SRC) (ST3), Unattached.SNK (unattached SNK) (ST4), AttachWait.SNK (attached waiting SNK) (ST5) and Attached.SNK (attached SNK) (ST6), and takes any state at any point in time.

[0045] In the state before the connection of the USB cable 2 , the mobile power source 100 repeats the state transition (DRP switching operation) between Unattached.SRC ( ST1 ) and Unattached.SNK ( ST4 ).

[0046] When the USB cable 2 is connected, the condition of "connection detected" is satisfied, and the mobile power 100 switches from Unattached.SRC (ST1) to AttachWait.SRC (ST2) (sequence SQ1). When a condition such as the power supply voltage between the mobile power 100 and the PC 200 is satisfied, the mobile power 100 switches from AttachWait.SRC (ST2) to Attached.SRC (ST3) (sequence SQ2). Attached.SRC (ST3) means a state in which the connection of the device as the power supply side is recognized. In this case, the power supply from the mobile power 100 to the PC 200 is started (sequence SQ3).

[0047] If the battery has sufficient charging capacity, the power bank 100 can manage the state transition, such as Figure 2 As shown, however, when the discharge voltage of the battery drops to a state where the discharge voltage cannot operate as a system and the state transition becomes "battery exhausted", the state transition cannot be managed. As a result, it is fixed to Unattached.SNK (ST4) (sequence SQ4). Unattached.SNK (ST4) means a connection waiting state as SNK.

[0048] When the mobile power 100 recovers from "battery exhaustion" by supplying power from the connected PC 200 (DRP device), it restarts managing state transitions. At this time, since the connected PC 200 is an SRC, the "source detected" condition is satisfied, and the mobile power 100 transitions from Unattached.SNK (ST4) to AttachWait.SNK (ST5) (sequence SQ5). When conditions such as the power supply voltage between the mobile power 100 and the PC 200 are satisfied, the mobile power 100 transitions to Attached.SNK (ST6) (sequence SQ6). Attached.SNK (ST6) means that the connection of the device as the power receiving side is recognized. In this case, power supply from the PC 200 to the mobile power 100 is started (sequence SQ7).

[0049] That is to say, Figure 1 As shown in FIG. 2D , the electric power supplied from the mobile power source 100 to the PC 200 is reversely supplied from the PC 200 to the mobile power source 100 .

[0050] Figure 3 is shown with Figure 2 A sequence diagram showing the sequence of state transitions. Figure 3 The process performed in each of the mobile power supply 100 and the PC 200 implementing the DRP function is shown. Note that Figure 3 The value ("Rp" or "Rd") after "CC:" shown in some steps of the present invention means the resistance value (pull-up resistor and pull-down resistor (see the pull-down resistor described later) appearing on the communication lines (CC1 and CC2) included in the USB cable 2. Figure 5 )), and the value (“enable” or “disable”) after “VBUS:” means whether a prescribed voltage is supplied to a power line included in the USB cable 2.

[0051] Generally, “enable” means a state in which a voltage equal to or higher than the vSafe5V voltage according to the USB Type-C standard is applied to the power line, and “disable” means a state in which vSafe0V according to the USB Type-C standard is applied to the power line.

[0052] refer to Figure 3 , the mobile power supply 100 is initially Unattached.SRC (step S1). At this time, the mobile power supply 100 shows the resistor Rp in the communication line and does not generate a prescribed voltage in the power line.

[0053] In this specification, “showing a resistance value Rp on the communication line” and “showing a resistance value Rd on the communication line” respectively mean “connecting a pull-up resistor to the communication line” and “connecting a pull-down resistor to the communication line.” The same applies to the following description.

[0054] The PC 200 is initially set to Unattached.SNK (step S11). At this time, the PC 200 shows the resistor Rd in the communication line and does not generate a prescribed voltage in the power line.

[0055] The mobile power 100 determines that the "connection detected" condition is satisfied by detecting the presence of the connected PC 200, and switches from Unattached.SRC to AttachWait.SRC (step S2). In addition, the mobile power 100 determines that the "reception detected" condition is satisfied by detecting that the connected PC 200 is waiting for a response from SRC, and switches from AttachWait.SRC to Attached.SRC (step S3). In Attached.SRC, the mobile power 100 starts supplying a specified voltage to the power line.

[0056] On the other hand, the PC 200 determines that the "connection detected" condition is satisfied by detecting the presence of the connected mobile power 100, and switches from Unattached.SNK to AttachWait.SNK (step S12). In addition, the PC 200 determines that the "source detected" condition is satisfied by detecting that the connected mobile power 100 is waiting for a response from SNK, and switches from AttachWait.SNK to Attached.SNK (step S13).

[0057] When the mobile power 100 changes to Attached.SRC and the PC 200 changes to AttachWait.SNK, the mobile power 100 starts supplying power to the PC 200 (step S4 ), and the PC 200 starts receiving power from the mobile power 100 (step S14 ).

[0058] Thereafter, when the discharge voltage of the batteries in the mobile power source 100 drops to a condition where they cannot operate as a system, the mobile power source 100 shuts down the system and becomes "battery dead".

[0059] The system shutdown causes the mobile power 100 to switch from Attach.SRC to Unattached.SNK (step S5). At this time, the mobile power 100 shows the resistor Rd in the communication line by the system shutdown, and stops supplying the specified voltage to the power line.

[0060] On the other hand, when the PC 200 detects that the connection with the mobile power supply 100 as the SRC is disconnected due to the system shutdown of the mobile power supply 100, receiving power stops (step S15). The PC 200 transitions from Attached.SNK to UnattachWait.SNK (step S16).

[0061] Then, the PC 200 detects a state in which the connected mobile power source 100 exhibits resistance Rd in the communication line and does not generate a specified voltage in the power line by the DRP switching operation, and switches from UnattachWait.SNK to UnattachWait.SRC (step S17). That is, the PC 200 switches from SNK to SRC.

[0062] Then, the PC 200 determines that the “connection detected” condition is satisfied by detecting the presence of the connected mobile power source 100 , and transitions from Unattached.SRC to AttachWait.SRC (step S18 ).

[0063] In addition, the PC 200 determines that the "sink detected" condition is satisfied by detecting that the connected mobile power supply 100 is waiting for a response from the SRC (i.e., CC: Rd, VBUS: disabled), and switches from AttachWait.SRC to Attached.SRC (step S19). In Attached.SRC, the PC 200 starts supplying a specified voltage to the power line. That is, the PC 200 starts supplying power to the mobile power supply 100, which causes the mobile power supply 100 to recover from "battery exhaustion".

[0064] Then, by detecting the presence of the connected PC 200, the mobile power 100 determines that the condition of "connection detected" is satisfied, and switches from Unattached.SNK to AttachWait.SNK (step S6). In addition, the mobile power 100 determines that the condition of "source detected" is satisfied, and switches from AttachWait.SNK to Attached.SNK (step S7).

[0065] When the PC 200 changes to Attached.SRC and the mobile power source 100 changes to AttachWait.SNK, the PC 200 starts supplying power to the mobile power source 100 (step S20 ), and the mobile power source 100 starts receiving power from the PC 200 (step S8 ).

[0066] In the present embodiment, the problems of the processing of step S5 and subsequent steps of the mobile power source 100 and the processing of step S15 and subsequent steps of the PC 200 are solved.

[0067] As described above, when the power bank 100 and the external device are connected to each other via the USB Type C interface, if both devices have the DRP function, SRC and SNK are switched alternately.

[0068] Initially, after the external device has been charged until the battery of the mobile power supply 100 is empty, the power supply and reception operation should be stopped. However, between devices with the DRP function, power is returned from the external device to the mobile power supply 100, and the power supply and reception operation desired by the user cannot be achieved.

[0069] The present embodiment provides a configuration and process for preventing the electric power of the DRP device from automatically flowing back to the mobile power supply 100 when the charging operation from the mobile power supply 100 to the DRP device is completed, so as to solve the above-mentioned new problem. In other words, the present invention provides a mechanism for preventing the power supply direction from being reversed and preventing the supplied power from starting to return to the power source even if the USB cable remains connected after charging is completed when a DRP function capable of receiving power supply is implemented in a device compliant with the USB Type-C standard capable of supplying power and receiving power through a single port (both devices have a DRP function capable of supplying power and receiving power).

[0070] Typically, according to this embodiment, when power to the connection destination is disabled while power stored in a battery as a power supply side (SRC) is supplied to the connection destination, the mobile power source stops power supply to the connection destination while maintaining the state of the power supply side (SRC).

[0071] By adopting this configuration, an operation of exchanging roles between the supplier and the receiver can be avoided.

[0072] In the following description, the state in which power cannot be supplied to the connection destination is referred to as a "low battery" state. In this specification, "low battery" is the same as "battery exhausted" defined in the USB standard in that the power stored in the battery is reduced and the power cannot be supplied to the external device. However, in the "low battery" state, it is assumed that the power of the controller that can drive the own device is retained. In other words, "low battery" means a state in which power cannot be supplied to the connection destination but various controls can be performed by the controller.

[0073] First embodiment

[0074] As a first embodiment, the most simplified form will be described.

[0075] (C1: Device Configuration)

[0076] First, an exemplary device configuration of a mobile power source 100 according to a first embodiment will be described. Figure 4 is a schematic diagram showing an exemplary device configuration of the mobile power source 100 according to the first embodiment.

[0077] refer to Figure 4 The mobile power supply 100 includes a connector 102 , a power manager (power manager) 104 , a battery 106 , and a controller (Controller) 110 as main components.

[0078] The connector 102 includes a port for a USB Type C interface. The power manager 104 corresponds to a charge / discharge control circuit that controls the charge / discharge of the battery 106 according to an instruction from the controller 110. Specifically, the power manager 104 can selectively perform: a first charging operation of storing electric power supplied from an external power source in the battery 106; a second charging operation of storing electric power supplied from an external device in the battery 106; and a discharging operation of supplying the electric power stored in the battery 106 to the external device.

[0079] The battery 106 is a storage battery configured to be chargeable and dischargeable, and for example, a lithium ion secondary battery, a lithium ion polymer secondary battery, a nickel-metal hydride rechargeable battery, or the like is used.

[0080] The controller 110 provides a port corresponding to a DRP according to the USB Type-C standard, which can be both a power supply side (SRC) and a power receiving side (SNK). That is, the controller 110 functions as a DRP and manages communication with a connection destination via the USB cable 2 and power supply and reception operations. More specifically, the controller 110 includes a processor 112 and a signal transmission module (PHY&LGC) 116. The processor 112 is connected to the signal transmission module 116 and the power manager 104.

[0081] The processor 112 corresponds to a state manager that performs a sequence according to the USB Type-C standard. The processor 112 executes the firmware 114, which is an example of a control program, thereby providing the following processing and functions. That is, the state manager can be implemented by the processor 112 executing the firmware 114, which is an example of a control program. An implementation using the processor 112 and the firmware 114 can facilitate sequence modification, version upgrade, etc. Instead of a software implementation using the processor 112, a hardware implementation described later may be adopted.

[0082] The signal transmission module 116 exchanges signals with the connection destination via the communication line (first communication line (CC1) 21 and second communication line (CC2) 22) in the USB cable 2 according to the instruction from the processor 112 corresponding to the state management module. The first communication line 21 and the second communication line 22 may be collectively referred to as "communication lines". The detailed configuration of the signal transmission module 116 will be described later.

[0083] The processor 112 corresponding to the state manager is coupled to the power manager 104 for controlling the charging and discharging of the battery 106. An optional control interface may be provided between the processor 112 and the power manager 104. Such a control interface mediates the sending of control commands for controlling the charging and discharging by the power manager 104 according to instructions from the processor 112. For example, control signals may be exchanged between the processor 112 and the power manager 104 according to an I2C interface.

[0084] Power is exchanged between the battery 106 and the external device via the VBUS 23 in the USB cable 2. The USB cable 2 may include a shielded wire (not shown).

[0085] Figure 5 1 is a schematic diagram showing an example of a circuit configuration of the controller 110 according to the first embodiment. Figure 5 , the signal transmission module 116 of the controller 110 exchanges various control signals via the first communication line 21 (CC1) and the second communication line 22 (CC2).

[0086] More specifically, the signal transmission module 116 includes a first communication control block (Comm. Block) 1161 and a second communication control block (Comm. Block) 1162 .

[0087] The first communication control block 1161 outputs data received via the first communication line 21 to the processor 112, and transmits data from the processor 112 via the first communication line 21. Similarly, the second communication control block 1162 outputs data received via the second communication line 22 to the processor 112, and transmits data from the processor 112 via the second communication line 22.

[0088] The signal transmission module 116 has resistors respectively connected between the communication lines (the first communication line 21 and the second communication line 22 ) and the power supply potential Vs and the ground potential GND to detect connection with a connection destination.

[0089] Specifically, a pull-up resistor 1165 having a resistance value Rp between the first communication line 21 and the power supply potential Vs is connected to the first communication line 21, and a pull-down resistor 1166 having a resistance value Rd between the first communication line 21 and the ground potential GND is connected to the first communication line 21. Similarly, a pull-up resistor 1167 having a resistance value Rp between the second communication line 22 and the power supply potential Vs is connected to the second communication line 22, and a pull-down resistor 1168 having a resistance value Rd between the second communication line 22 and the ground potential GND is connected to the second communication line 22.

[0090] Switches 1163 and 1164 electrically connect / disconnect the path from the communication line (first communication line 21 and second communication line 22) to the power supply potential Vs and the ground potential GND. More specifically, switch 1163 connects / disconnects pull-up resistor 1165 or pull-down resistor 1166 to / from the first communication line 21 according to a control signal from processor 112. Similarly, switch 1164 electrically connects / disconnects pull-up resistor 1167 or pull-down resistor 1168 to / from the second communication line 22 according to a control signal from processor 112.

[0091] By detecting voltages corresponding to the resistances Rp and Rd generated in the first communication line 21 and the second communication line 22 , respectively, a connection between the mobile power source 100 and the connection destination is established.

[0092] In this way, the signal transmission module 116 can selectively connect the pull-up resistors 1165 and 1167 (first resistor) indicating SRC (power supply side) or the pull-down resistors 1166 and 1168 (second resistor) indicating SNK (power receiving side) to the communication lines (first communication line 21 and second communication line 22).

[0093] (c2: state transition)

[0094] Next, the state transition of the mobile power source 100 according to the first embodiment will be described. Figure 6 is a diagram showing a main part of state transition of the mobile power source 100 according to the first embodiment. Figure 6 The state transitions shown are similar to Figure 2 The state transition of the device responsible for the port role of DRP according to the USB Type-C standard is different in that UnattachWait_LB.SRC (ST7) is added. Figure 6 In, with Figure 2 The same reference numerals are used to represent substantially the same states as those shown. Figure 2 Description A description of the status.

[0095] The transition to UnattachWait_LB.SRC (ST7) is performed when the mobile power supply 100 changes to "low battery" in Attached.SRC (ST3).

[0096] Under Attached.SRC (ST3), the mobile power supply 100 supplies power to the DRP device. In this case, the mobile power supply 100 switches to UnattachWait_LB.SRC (ST7) before becoming "battery exhausted", and the battery 106 of the mobile power supply 100 has dropped to a "low battery" condition, which allows the controller 110 to operate, but is insufficient to power the DRP device.

[0097] In UnattachWait_LB.SRC (ST7), the mobile power supply 100 maintains the resistivity Rp present on the communication line without generating a specified voltage on the power line.

[0098] Therefore, the processor 112 corresponding to the state manager connects the pull-up resistors 1165, 1167 (first resistor) of the instruction SRC (power supply side) to the communication line, and stops supplying power to the connection destination while the power stored in the battery 106 is supplied to the DRP device connected to the power, while maintaining the pull-up resistors 1165, 1167 (first resistor) connected to the communication line. By adopting this configuration, SNK is not fixed as hardware to the connection waiting state (Unattached.SNK) of SNK, as described in the related art. As a result, it is possible to avoid the operation of alternating SRC and SNK between devices.

[0099] Next, if the DRP device is physically disconnected from the DRP device to which the DRP device is connected when the DRP device is in UnattachWait_LB.SRC (ST7), the state transitions to another state. More specifically, as one of the transition conditions from UnattachWait_LB.SRC (ST7), it is defined that the communication line is disconnected (hereinafter also referred to as the "first transition condition"). That is, similar to the transition condition from Attached.SRC (ST3), when the state of the communication line becomes SRC.Open, the mobile power supply 100 transitions from UnattachWait_LB.SRC (ST7) to Unattached.SNK (ST4). SRC.Open means that the communication line is disconnected and a state of infinite resistivity occurs in the communication line. As described above, when the communication line is disconnected, the processor 112 corresponding to the state manager determines that the connection with the connection destination is disconnected.

[0100] Under Unattached.SNK ST4, the mobile power supply 100 shows the resistor Rp on the communication line. That is, when the connection with the connection destination is disconnected, the processor 112 corresponding to the state manager connects the pull-down resistors 1166 and 1168 (second resistor) indicating SNK (power receiving side) to the communication line (first communication line 21 and second communication line 22), instead of connecting the pull-up resistors 1165 and 1167 (first resistor) indicating SRC (power supply side) to the communication line.

[0101] As described above, in the mobile power supply 100 according to the first embodiment, when the remaining capacity of the battery 106 becomes small and the remaining capacity becomes "low battery", the resistance value Rp appearing on the communication line is maintained, and the supply of the prescribed voltage to the power line is stopped. The mobile power supply 100 maintains its state until the connection with the DRP device is physically disconnected. Thereafter, when the mobile power supply 100 is physically disconnected from the DRP device, the DRP device is converted to a state in which the DRP device presents a resistivity Rd on the communication line.

[0102] Even if the power cannot be supplied from the mobile power 100 to the DRP device by adding UnattachWait_LB.SRC (ST7), which is a new state, the mobile power 100 is not fixed to the connection waiting state (Unattached.SNK (ST4)) of SNK, so that the DRP device does not switch from SNK to SRC, and the operation of depriving the previously charged DRP device of power can be avoided.

[0103] As a specific sequence, when the mobile power source 100 becomes "low battery" after the mobile power source 100 starts supplying power to the PC 200, the mobile power source 100 transitions from Attached.SRC (ST3) to UnattachWait_LB.SRC (ST7) (sequence SQ41).

[0104] In this state, the mobile power 100 maintains its state until the connection with the DRP device is physically disconnected (sequence SQ42). If it is determined that the connection with the DRP device is physically disconnected, the mobile power 100 switches from UnattachWait_LB.SRC (ST7) to Unattached.SNK (ST4) (sequence SQ43). Figure 2 The state transitions shown are the same.

[0105] (c3: Processing sequence)

[0106] Next, according to the first embodiment, an example of a processing sequence of power supply and reception operations performed between the mobile power source 100 and the PC 200 as an example of a DRP device will be described.

[0107] Figure 7 1 is a sequence diagram showing a processing sequence related to power supply and reception operations performed between the mobile power source 100 and the PC 200 according to the first embodiment. Figure 7 In the sequence diagram shown, Figure 3 The same processes are denoted by the same reference numerals as shown in the sequence diagram. Figure 3 Description A description of the process described.

[0108] Figure 7 shows a processing sequence when power is supplied from the mobile power supply 100 to the PC 200, similar to Figure 3 Specifically, the mobile power source 100 switches from Unattached.SRC to Attach.SRC via AttachWait.SRC (steps S1, S2, S3), and starts supplying power to the PC 200 (step S4).

[0109] On the other hand, the PC 200 transitions from Unattached.SNK to Attach.SNK via AttachWait.SNK (steps S11 , S12 , S13 ), and starts receiving power from the mobile power source 100 (step S14 ).

[0110] In this way, the controller 110 of the mobile power source 100 connects the pull-up resistors 1165 and 1167 (first resistor; resistance value Rp) indicating SRC (power supply side) to the communication line, and supplies the electric power stored in the battery 106 to the connection destination.

[0111] Thereafter, when the discharge voltage of the battery 106 in the mobile power supply 100 drops to a predetermined value, the mobile power supply 100 becomes "low battery" and the discharge voltage is switched from Attach.SRC to UnattachWait_LB.SRC (step S21). In this case, the power from the mobile power supply 100 to the PC 200 is stopped. However, the mobile power supply 100 maintains the state of SRC.

[0112] On the other hand, by stopping the supply of electric power from the mobile power source 100, the PC 200 stops receiving electric power (step S15). Then, the PC 200 transitions from Attached.SNK to UnattachWait.SNK (step S16).

[0113] Therefore, when power supply to the connection destination becomes impossible during power supply, the controller 110 of the mobile power supply 100 stops supplying power to the connection destination while maintaining the pull-up resistors 1165, 1167 (first resistor; resistance value Rp) indicating SRC (power supply side) connected to the communication line.

[0114] Furthermore, by detecting the presence of the connected mobile power source 100 , the PC 200 determines that the condition of “connection detected” is satisfied, and transitions from Unattached.SNK to AttachWait.SNK (step S31 ).

[0115] The mobile power 100 maintains UnattachWait_LB.SRC, and the PC 200 maintains AttachWait.SNK, until the connection between the mobile power 100 and the PC 200 is physically disconnected.

[0116] If it is determined that the connection between the mobile power 100 and the PC 200 is physically disconnected (step S32), the mobile power 100 detects that the connection destination PC 200 no longer exists, determines that the "disconnection detected" condition is satisfied, and transitions from UnattachWait_LB.SRC to Unattached.SNK (step S22).

[0117] According to the first embodiment, the situation where the mobile power supply 100 draws power from the PC 200 through the above-mentioned processing sequence can be avoided. In other words, according to the first embodiment, the above-mentioned problem is solved by optimizing the processing of step S21 and subsequent steps of the mobile power supply 100 and the processing of step S15 and subsequent steps of the PC 200.

[0118] (c4: Operation example)

[0119] Next, according to the first embodiment, an example of power supply and reception operations performed between the mobile power source 100 and the PC 200 as an example of a DRP device will be described.

[0120] Figure 8 2 is a schematic diagram showing an exemplary operation of power supply and reception operations performed between the mobile power source 100 and the PC 200 according to the first embodiment. Figure 8 It shows that when Figure 1 2. An exemplary operation when power is supplied from the mobile power source 100 to the PC 200 in the same manner as in FIG.

[0121] refer to Figure 8 A, the mobile power supply 100 starts to supply power to the PC 200. Figure 8As shown in FIG. 1B , when the mobile power supply 100 becomes “low battery”, the power supply from the mobile power supply 100 to the PC 200 stops (VBUS is disabled), but the mobile power supply 100 maintains the SRC state. The mobile power supply 100 maintains the SRC state until the connection between the mobile power supply 100 and the DRP is physically disconnected.

[0122] like Figure 8 As shown in C, when it is determined that the mobile power 100 and the PC 200 (DRP device) are physically disconnected, the mobile power 100 switches from SRC to SNK.

[0123] By switching to SNK, such as Figure 8 As shown in FIG. 2 , the mobile power source 100 can charge the battery 106 by receiving electric power supplied from an external power source such as a power adapter 300 .

[0124] As described above, according to the first embodiment, when the mobile power supply 100 becomes "low battery", the mobile power supply 100 transitions to UnattachWait_LB.SRC, and by disabling VBUS while maintaining the resistance value of the communication line at the resistance value Rp, it is possible to maintain the state without obtaining power from the DRP device (PC 200) as the power target, and receive power supplied from the external power supply after determining that the connection with the DRP device is physically disconnected.

[0125] (c5: Processing)

[0126] Fig. 9 1 is a flowchart showing a processing procedure related to the power supply operation of the mobile power source 100 according to the first embodiment. Fig. 9 The steps of the mobile power supply 100 shown are generally implemented by the firmware 114 executed as a control program by the processor 112 of the controller 110. Therefore, Fig. 9 Each of the steps shown is typically performed by the processor 112 .

[0127] refer to Fig. 9 , the processor 112 determines whether the discharge voltage of the battery 106 has dropped to a predetermined voltage while supplying power to the DRP device under Attached.SRC (step S100). If the discharge voltage of the battery 106 has not dropped to a predetermined value ("No" in step S100), the processor 112 repeats the process of step S100.

[0128] If the discharge voltage of the battery 106 has dropped to a predetermined value ("Yes" in step S100), the processor 112 stops the power supply to the DRP device via the power line while maintaining the resistance value Rp on the communication lines (first communication line 21 and second communication line 22) (step S102).

[0129] Then, processor 112 determines whether the communication lines (first communication line 21 and second communication line 22) are disconnected (step S104). If the communication lines are not disconnected ("No" in step S104), processor 112 repeats the process of step S104.

[0130] If the communication line is disconnected (YES in step S104 ), processor 112 changes the resistance value shown in the communication line (first communication line 21 and second communication line 22 ) from Rp to Rd (step S106 ), and terminates the power supply operation to the DRP device.

[0131] (c6: Advantages)

[0132] The mobile power supply 100 according to the first embodiment detects the "low battery" state, stops supplying power to the DRP device, shows a resistance value Rp on the communication line, and maintains the source (SRC) state until the discharge voltage of the battery 106 decreases ("battery exhausted") until it cannot operate as a system. As a result, it is possible to prevent the DRP device that has been supplied with power from being switched to the source DRP device. Since the DRP device is not switched to the source, the operation of the mobile power supply 100 drawing power from the previously charged DRP device can be avoided.

[0133] In addition, in the mobile power supply 100 according to the first embodiment, when it is determined that the connection with the DRP device is physically disconnected, the connection is switched from the source (SRC) to the sink (SNK), so that the battery 106 can be charged by supplying power from an external power source such as a power adapter 300 according to the USB Type-C standard.

[0134] Second embodiment

[0135] Next, as a second embodiment, a configuration in which the transition condition from UnattachWait_LB.SRC (ST7) adopted in the first embodiment is different will be described. Except for the condition of transition from UnattachWait_LB.SRC (ST7), other configurations and processes are the same as those in the first embodiment, so their detailed description will not be repeated.

[0136] (d1: state transition)

[0137] The state transition of the mobile power source 100 according to the second embodiment is described. Fig.10 is a diagram showing a main part of state transition of the mobile power source 100 according to the second embodiment. Fig.10 The state transitions shown are similar to Figure 6The state transition of the mobile power supply 100 according to the first embodiment shown is different in that the ErrorRecovery (ST8) state is taken into consideration. Fig.10 In, with Figure 6 The same reference numerals are used to represent substantially the same states as those shown. Figure 6 Description A description of the status.

[0138] ErrorRecovery (ST8) is a state that is switched when an optional condition is satisfied, and a recovery process is performed when it is determined that an abnormality has occurred. More specifically, under ErrorRecovery (ST8), after the communication line remains disconnected for a predetermined period (tErrorRecovery), the communication line switches to Unattached.SNK (ST4) or Unattached.SRC (ST1). At this time, a DRP switching operation for state switching between Unattached.SNK (ST4) and Unattached.SRC (ST1) is also performed.

[0139] Here, if the DRP device connected to the mobile power 100 transitions to ErrorRecovery (ST8) by satisfying certain conditions, the communication line of the connected DRP device becomes disconnected. That is, from the perspective of the mobile power 100, it is determined that the state of the connected communication line has become SRC.Open.

[0140] When the mobile power 100 is in UnattachWait_LB.SRC (ST7), if the DRP device of the connection destination transitions to ErrorRecovery (ST8), the mobile power 100 determines that the connection with the DRP device has been physically disconnected (error), and thus transitions to Unattached.SNK (ST4), and switches from SRC to SNK.

[0141] Therefore, in the second embodiment, only when it is determined that the USB cable 2 connecting the mobile power 100 and the DRP device is physically pulled out, the mobile power 100 transitions from UnattachWait_LB.SRC (ST7) to Unattached.SNK (ST4) (sequence SQ44).

[0142] That is, in the second embodiment, a transition condition different from the transition condition (first transition condition) from UnattachWait_LB.SRC (ST7) adopted in the first embodiment is adopted to prevent erroneous state transition.

[0143] As described above, even if the USB cable 2 connecting the mobile power supply 100 and the DRP device is not physically pulled out, under the conversion condition adopted in the first embodiment, it is determined that the USB cable 2 connecting the mobile power supply 100 and the DRP device will not be physically pulled out through the conversion condition to ErrorRecovery (ST8) or the DRP switching operation, and therefore, in order to ensure that the connection is actually physically pulled out, the conversion condition described below (hereinafter referred to as the "second conversion condition") is adopted.

[0144] Second transition condition: The state of (voltage appearing at CC1 ≠ vRd and voltage appearing at CC2 ≠ vRd) lasts for more than time (= tErrorRecovery + tDRP), where tErrorRecovery means the time to keep the communication line disconnected under ErrorRecovery (ST8). tDRP means the time required to perform a DRP switching operation. According to the USB Type-C standard, tErrorRecovery is set to 240ms and tDRP is set to 100ms.

[0145] Furthermore, vRd means a voltage appearing on a communication line when the own device is a source (SRC) and the connected DRP device is a sink (SNK).

[0146] That is, in the case where the self-controller is SRC (power supply side) and the connection destination is SNK (power receiving side), when a voltage different from the voltage that should appear on the communication line continues for a predetermined time on the communication line, the processor 112 corresponding to the state manager determines that the connection with the connection destination is disconnected. Here, the predetermined time may be set to be equal to or longer than the sum of the time required to maintain the disconnected communication line in the ErrorRecovery state and the time required for the DRP switching operation.

[0147] In other words, the second transition condition means that, when viewed from the mobile power supply 100, a voltage different from the voltage (vRd) appearing on the communication line corresponding to the state of the connected DRP device continues to exceed the time required for transition to ErrorRecovery (ST8) or the time required for the DRP switching operation.

[0148] Only when the above-mentioned second transition condition is satisfied at UnattachWait_LB.SRC ( ST7 ), the mobile power supply 100 according to the second embodiment transitions to Unattached.SNK ( ST4 ) (sequence SQ44 ).

[0149] By adopting the second transition condition as described above, even if transition to ErrorRecovery ( ST8 ) or a DRP switching operation occurs in the connected DRP device, the mobile power supply 100 does not erroneously determine that the connection with the DRP device has been physically disconnected.

[0150] Next, an example of a processing sequence of a power supply and reception process performed between the mobile power source 100 and the PC 200 as an example of a DRP device according to the second embodiment will be described.

[0151] Fig.11 1 is a sequence diagram showing a processing sequence when ErrorRecovery occurs in a power supply and reception operation performed between the mobile power source 100 and the PC 200 according to the first embodiment. Fig.11 In the sequence diagram shown, Figure 3 or Figure 7 The same reference numerals are used to represent substantially the same processes in the sequence diagrams shown. Figure 3 or Figure 7 Description A description of the process described.

[0152] and Figure 7 similar, Fig.11 1 shows a process sequence when power is supplied from the mobile power 100 to the PC 200. Specifically, the mobile power 100 switches from Unattached.SRC to Attach.SRC via AttachWait.SRC (steps S1, S2, S3), and starts supplying power to the PC 200 (step S4).

[0153] On the other hand, the PC 200 transitions from Unattached.SNK to Attach.SNK via AttachWait.SNK (steps S11 , S12 , S13 ), and starts receiving power from the mobile power source 100 (step S14 ).

[0154] Thereafter, when the discharge voltage of the battery 106 in the mobile power supply 100 drops to a predetermined value, the mobile power supply 100 becomes "low battery", and the discharge voltage is switched from Attach.SRC to UnattachWait_LB.SRC (step S21). In this state, the power from the mobile power supply 100 to the PC 200 is stopped. However, the mobile power supply 100 maintains the state of SRC.

[0155] On the other hand, by stopping the supply of electric power from the mobile power supply 100, the PC 200 stops receiving electric power (step S15). Then, the PC 200 switches from Attached.SNK to UnattachWait.SNK (step S16). In addition, by detecting the presence of the connected mobile power supply 100, the PC 200 determines that the condition of "connection detected" is satisfied, and switches from Unattached.SNK to AttachWait.SNK (step S31).

[0156] In this case, it is assumed that the PC 200 transitions to ErrorRecovery. In other words, when a certain condition is satisfied, the PC 200 transitions to ErrorRecovery (step S33). In ErrorRecovery, the state of the communication line of the PC 200 is SRC.Open.

[0157] On the other hand, when the state of the communication line of the PC 200 becomes SRC.Open, the mobile power supply 100 determines that the condition of “disconnection detected” is satisfied, and transitions from UnattachWait_LB.SRC to Unattached.SNK (step S22 ).

[0158] After tErrorRecovery has passed, the PC 200 switches to Unattached.SRC (step S34). That is, the PC 200 switches from SNK to SRC.

[0159] Then, the PC 200 determines that the "connection detected" condition is satisfied by detecting the presence of the connected mobile power 100, and switches from Unattached.SRC to AttachWait.SRC (step S18). In addition, the PC 200 determines that the "sink detected" condition is satisfied by detecting that the connected mobile power 100 is waiting for a response from the SRC (i.e., CC: Rd, VBUS: disabled), and switches from AttachWait.SRC to Attached.SRC (step S19).

[0160] On the other hand, the mobile power source 100 determines that the condition of “source detected” is satisfied, and transitions from AttachWait.SNK to AttachWait.SNK (step S7 ).

[0161] When the PC 200 changes to Attached.SRC and the mobile power source 100 changes to AttachWait.SNK, the PC 200 starts supplying power to the mobile power source 100 (step S20 ), and the mobile power source 100 starts receiving power from the PC 200 (step S8 ).

[0162] As described above, when the mobile power 100 is UnattachWait_LB.SRC, if the connected DRP device switches to ErrorRecovery for some reason, the mobile power 100 may mistakenly determine that the connection with the DRP device has been physically disconnected and may switch to Unattached.SNK. In this case, the DRP device switches to Attach.SRC via Unattached.SRC, and the roles of power supply and reception are inadvertently reversed.

[0163] In the second embodiment, by adopting the second transition condition as described above, even if the DRP device of the connection destination is transitioned to the ErrorRecovery DRP device, it is possible to avoid erroneously determining that the connection is physically disconnected.

[0164] Fig.12 1 is a sequence diagram showing a process sequence related to power supply and reception operations performed between the mobile power source 100 and the PC 200 according to the second embodiment. Fig.12 In the sequence diagram shown, Figure 3 , Figure 7 or Fig.11 The same processes are denoted by the same reference numerals as shown in the sequence diagram. Figure 3 , Figure 7 or Fig.11 Description A description of the process described.

[0165] and Fig.11 similar, Fig.12 1 shows a processing sequence when power is supplied from the mobile power source 100 to the PC 200. Specifically, the mobile power source 100 transitions from Unattached.SRC to Attach.SRC via AttachWait.SRC (steps S1, S2, S3), and starts supplying power to the PC 200 (step S4).

[0166] On the other hand, the PC 200 transitions from Unattached.SNK to Attach.SNK via AttachWait.SNK (steps S11 , S12 , S13 ), and starts receiving power from the mobile power source 100 (step S14 ).

[0167] In this way, the controller 110 of the mobile power source 100 connects the pull-up resistors 1165 and 1167 (first resistor; resistance value Rp) indicating SRC (power supply side) to the communication line, and supplies the electric power stored in the battery 106 to the connection destination.

[0168] Thereafter, when the discharge voltage of the battery 106 in the mobile power supply 100 drops to a predetermined value, the mobile power supply 100 becomes "low battery" and the discharge voltage is switched from Attach.SRC to UnattachWait_LB.SRC (step S21). In this case, the power from the mobile power supply 100 to the PC 200 is stopped. However, the mobile power supply 100 maintains the state of SRC.

[0169] On the other hand, by stopping the supply of electric power from the mobile power source 100, the PC 200 stops receiving electric power (step S15). Then, the PC 200 transitions from Attached.SNK to UnattachWait.SNK (step S16).

[0170] In this way, the controller 110 of the mobile power source 100 connects the pull-up resistors 1165 and 1167 (first resistor; resistance value Rp) indicating SRC (power supply side) to the communication line, and supplies the electric power stored in the battery 106 to the connection destination.

[0171] In this case, it is assumed that PC 200 switches to ErrorRecovery. In other words, when a certain condition is satisfied, PC 200 switches to ErrorRecovery (step S33). Under ErrorRecovery, the state of the communication line of PC 200 is SRC.Open. Then, after tErrorRecovery has passed, PC 200 switches to Unattached.SRC (step S34). In addition, PC 200 switches from UnattachWait.SRC to UnattachWait.SNK (step S16) by the DRP switching operation. At this time, PC 200 shows resistor Rd in the communication line and does not generate a prescribed voltage in the power line.

[0172] For ErrorRecovery, the time required for the transition from ErrorRecovery (step S33) to Unattached.SRC (step S34) is tErrorRecovery, and the time required for the transition from Unattached.SRC (step S34) to UnattachWait.SNK (step S16) is tDRP. That is, although the state of the communication line in the PC 200 becomes SRC.Open by transitioning to ErrorRecovery, the resistor Rd appears on the communication line after a certain period of time (=tErrorRecovery+tDRP) has passed. That is, the voltage vRd appears on the communication line.

[0173] Therefore, the state of (voltage appearing at CC1 ≠ vRd and voltage appearing at CC2 ≠ vRd) does not continue for more than the period (=tErrorRecovery+tDRP), and the transition condition is not satisfied. As a result, the mobile power supply 100 does not erroneously determine that the connection with the DRP device has been physically disconnected, and maintains UnattachWait_LB.SRC.

[0174] On the other hand, the PC 200 determines that the “connection detected” condition is satisfied by detecting the presence of the connected mobile power source 100 , and transitions from Unattached.SNK to AttachWait.SNK (step S31 ).

[0175] Finally, when the connection between the mobile power 100 and the PC 200 is actually physically disconnected (step S32), the mobile power 100 determines that the transition condition according to the second embodiment is satisfied, and transitions from UnattachWait_LB.SRC to Unattached.SNK (step S22).

[0176] As described above, when the mobile power 100 is UnattachWait_LB.SRC, even if the connected DRP device switches to error recovery for some reason and then switches to Unattached.SRC, the mobile power 100 is maintained in UnattachWait_LB.SRC. As a result, the DRP device eventually also switches to and remains in AttachWait.SNK, thereby preventing the DRP device from inadvertently reversing the roles of power supply and reception.

[0177] (d3: Operation example)

[0178] Next, according to the second embodiment, an example of power supply and reception operations performed between the mobile power source 100 and the PC 200 as an example of a DRP device will be described.

[0179] Fig.13 2 is a schematic diagram showing an exemplary operation of power supply and reception operations performed between the mobile power source 100 and the PC 200 according to the second embodiment. Fig.13 A shows an operation example when ErrorRecovery occurs in the power supply and reception operation performed between the mobile power source 100 and the PC 200 according to the first embodiment as a comparative example, and Fig.13 B shows an operation example when ErrorRecovery occurs in the power supply and reception operation performed between the mobile power source 100 and the PC 200 according to the first embodiment.

[0180] refer to Fig.13 A, when the mobile power supply 100 becomes "low battery" during the power supply from the mobile power supply 100 to the PC 200 according to the first embodiment, the power supply from the mobile power supply 100 to the PC 200 is stopped. Here, when the PC 200 transitions to ErrorRecovery, the state of the communication line becomes SRC.Open. As a result, it is determined that the transition condition adopted in the first embodiment is satisfied, thereby inadvertently reversing the roles of supplying and receiving power between the power supply 100 and the PC 200.

[0181] On the other hand, reference Fig.13 B, when the mobile power supply 100 becomes "low battery" during the power supply from the mobile power supply 100 to the PC 200 according to the second embodiment, the power supply from the mobile power supply 100 to the PC 200 is stopped. Here, even if the PC 200 switches to ErrorRecovery, the switching condition adopted in the second embodiment is not satisfied, so that the situation in which the roles of power supply and reception are inadvertently reversed between the mobile power supply 100 and the PC 200 can be avoided.

[0182] (d4: Processing)

[0183] Fig.14 : is a flowchart showing a processing procedure related to a power supply operation of the mobile power source 100 according to the second exemplary embodiment. Fig.14 The steps of the mobile power supply 100 shown are generally implemented by the firmware 114 executed as a control program by the processor 112 of the controller 110. Fig.14 The subject of each of the steps shown is generally processor 112 .

[0184] refer to Fig.14 , the processor 112 determines whether the discharge voltage of the battery 106 has dropped to a predetermined voltage while supplying power to the DRP device under Attached.SRC (step S200). If the discharge voltage of the battery 106 has not dropped to a predetermined value ("No" in step S200), the processor 112 repeats the process of step S200.

[0185] If the discharge voltage of the battery 106 has dropped to a predetermined value (YES in step S200), the processor 112 stops supplying power to the DRP device via the power line while maintaining the resistance value Rp on the communication lines (first and second communication lines 21 and 22) (step S202).

[0186] Then, the processor 112 determines whether the voltage appearing on the communication line (the first communication line 21 and the second communication line 22) is different from vRd (step S204). If the voltage appearing on the communication line (the first communication line 21 and the second communication line 22) is substantially consistent with vRd ("No" in step S204), the processor 112 repeats the process of step S204.

[0187] If the voltage appearing on the communication lines (first communication line 21 and second communication line 22) is different from vRd (YES in step S204), the processor 112 determines whether the state of the communication lines continues for more than the time (=tErrorRecovery+tDRP) (step S206).

[0188] If the state of the communication line does not continue for more than the time (=tErrorRecovery+tDRP) ("NO" in step S206), processor 112 repeats the process of step S204.

[0189] If the state of the communication line continues for more than the time (=tErrorRecovery+tDRP) ("Yes" in step S206), the processor 112 changes the resistance value shown in the communication line (first communication line 21 and second communication line 22) from Rp to Rd (step S208) and terminates the power supply operation to the DRP device.

[0190] (d5: Advantages)

[0191] The USB Type-C standard allows transition to ErrorRecovery at any time to reset the connection between devices. According to the second embodiment, when the mobile power supply 100 is in UnattachWait_LB.SRC, even if ErrorRecovery occurs, since it is not erroneously determined that the connection with the DRP device is physically disconnected, the situation where the roles of power supply and reception are inadvertently reversed can be avoided.

[0192] The form, process, etc. other than those described above are the same as those in the above-described first embodiment, and therefore, a detailed description thereof will not be repeated here.

[0193] Third embodiment

[0194] The above-mentioned first and second embodiments describe the power supply and reception operation in the mobile power supply 100 using a single port corresponding to both power supply and power reception. The third embodiment will give a description of the power supply and reception operation suitable for a configuration using a plurality of ports corresponding to both power supply and power reception or a configuration additionally using a port for power reception.

[0195] The configuration and processing of the third embodiment other than the configuration and processing described below are the same as those of the above-described first embodiment or second embodiment, and thus a detailed description thereof will not be repeated.

[0196] (e1: state transition)

[0197] First, the state transition of the mobile power source 100 according to the third embodiment will be described. Fig.15 is a diagram showing a main part of state transition of the mobile power source 100 according to the third embodiment. Fig.15 The state transitions shown are similar to Figure 6 The state transition of the mobile power supply 100 according to the first embodiment shown is different in that a transition from UnattachWait_LB.SRC (ST7) to AttachWait.SRC (ST2) is added. Fig.15 In, with Figure 6 The same reference numerals are used to represent substantially the same states as those shown. Figure 6 Description A description of the status.

[0198] When multiple ports corresponding to both power supply and power reception are adopted, or when a port for power reception is additionally adopted, the battery can be charged through another port in a state connected to the DRP device. Therefore, when the "low battery" is resolved by the power received through another port after the mobile power supply 100 becomes "low battery" and the port transitions to UnattachWait_LB.SRC (ST7), the port transitions to AttachWait.SRC (ST2) (sequence SQ45). The process of detecting whether the connection with the DRP device is physically disconnected is terminated by the transition to AttachWait.SRC (ST2).

[0199] By providing a transition from UnattachWait_LB.SRC (ST7) to AttachWait.SRC (ST2), the power bank 100 can directly power the DRP device using power received via other ports.

[0200] As described above, in the third embodiment, as the transition condition from UnattachWait_LB.SRC (ST7), a condition in which the battery is restored from "low battery" due to charging (hereinafter also referred to as "third transition condition") is adopted. That is, when the battery 106 is charged and the power supply to the connection destination is restored to a condition in which the power supply to the connection destination is possible, the processor 112 corresponding to the state manager restarts the power supply to the connection destination according to the sequence as SRC (power supply side).

[0201] As described above, in the third embodiment, by adopting the third conversion condition suitable for the mobile power source 100 having a plurality of ports, a more appropriate power supply and reception operation is achieved.

[0202] (e2: device configuration)

[0203] Next, an example of a device configuration of the mobile power source 100 according to the third embodiment will be described. Fig.16 and Fig.17 is a schematic diagram showing an example of a device configuration of a mobile power source 100 according to a third embodiment. Fig.16 and Fig.17 A device configuration with multiple ports of a USB Type-C interface is shown. Fig.16 and Fig.17 In the device form shown, Figure 4 Identical elements of the illustrated device configuration are denoted by the same reference numerals.

[0204] refer to Fig.16 According to the third embodiment, the mobile power source 100 includes connectors 102A and 102B, power managers (power managers) 104A and 104B, a battery 106, and a controller (Controller) 110 as main components.

[0205] Connectors 102A and 102B include ports of USB Type-C interfaces.

[0206] The power managers 104A and 104B correspond to a charge / discharge control circuit for controlling the charge / discharge of the battery 106 according to an instruction from the controller 110 .

[0207] Controller 110 includes processor 112, signal transmission module (PHY & LGC) 116A connected to connector 102A, signal transmission module (PHY & LGC) 116B connected to connector 102B, and processor 112. Processor 112 is connected to signal transmission modules 116A, 116B and power managers 104A, 104B.

[0208] The processor 112 corresponds to a state manager that executes a sequence according to the USB Type C standard. The processor 112 executes firmware 114 as an example of a control program to control a sequence executed via each of the connectors 102A and 102B.

[0209] refer to Fig.17 , another mobile power source 100 according to the third embodiment includes connectors 102A and 102B, power source managers (power managers) 104A and 104B, a battery 106, and a controller (Controller) 110 as main components.

[0210] Controller 110 includes processors 112A and 112B, a signal transmission module (PHY & LGC) 116A connected to connector 102A, a signal transmission module (PHY & LGC) 116B connected to connector 102B, and processor 112. Signal transmission modules 116A and 116B are provided for each port.

[0211] Processor 112A is connected to signal transmission module 116A and power manager 104A. Processor 112B is also connected to signal transmission module 116B and power manager 104B. Furthermore, processor 112A and processor 112B are connected to each other.

[0212] The processor 112A executes the firmware 114A as an example of a control program to control the sequence executed via the connector 102A. The processor 112B controls the sequence executed via the connector 102B by executing the firmware 114B as an example of a control program.

[0213] because Fig.16 and Fig.17 The remaining configuration of the mobile power supply 100 is similar to Figure 4 The corresponding configuration of the illustrated mobile power source 100 is the same, so a detailed description thereof will not be repeated.

[0214] (e3: Processing sequence)

[0215] Next, an example of a processing sequence of a power supply and reception process performed between the mobile power source 100 and the PC 200 as an example of a DRP device according to the third embodiment will be described.

[0216] Fig.18 1 is a sequence diagram showing a process sequence related to power supply and reception operations performed between the mobile power source 100 and the PC 200 that do not adopt a conversion condition according to the third embodiment. Fig.18 In the sequence diagram shown, the processing that is substantially the same as any of the above sequence diagrams is denoted by the same reference numerals. The description of the above processing will not be repeated.

[0217] refer to Fig.18 , the mobile power supply 100 switches from Unattached.SRC to Attach.SRC via AttachWait.SRC (steps S1 , S2 , S3 ), and starts supplying power to the PC 200 (step S4 ).

[0218] On the other hand, the PC 200 transitions from Unattached.SNK to Attach.SNK via AttachWait.SNK (steps S11 , S12 , S13 ), and starts receiving power from the mobile power source 100 (step S14 ).

[0219] Thereafter, when the discharge voltage of the battery 106 in the mobile power supply 100 drops to a predetermined value, the mobile power supply 100 becomes "low battery" and the discharge voltage is switched from Attach.SRC to UnattachWait_LB.SRC (step S21). In this case, the power from the mobile power supply 100 to the PC 200 is stopped. However, the mobile power supply 100 maintains the state of SRC.

[0220] On the other hand, by stopping the supply of electric power from the mobile power supply 100, the PC 200 stops receiving electric power (step S15). Then, the PC 200 switches from Attached.SNK to UnattachWait.SNK (step S16). In addition, by detecting the presence of the connected mobile power supply 100, the PC 200 determines that the "connection detected" condition is satisfied, and switches from Unattached.SNK to AttachWait.SNK (step S31).

[0221] In this case, it is assumed that the mobile power supply 100 receives power via a port different from the port connected to the PC 200. That is, the mobile power supply 100 starts to receive electric power from an external power source (step S24). For example, the mobile power supply 100 can be powered by an external power source such as a power adapter 300. It is assumed that the battery 106 is charged by supplying power via other ports, and the "battery low" is eliminated.

[0222] In this way, even if the "low battery" of the mobile power supply 100 is resolved and power can be supplied to the DRP device, disconnection with the DRP device is not detected, so the connection is maintained at UnattachWait_LB.SRC and power supply cannot start.

[0223] As described above, when the first transition condition according to the first embodiment or the second transition condition according to the second embodiment is adopted instead of the third transition condition according to the third embodiment, when the mobile power supply 100 is in UnattachWait_LB.SRC, even if the "low battery" is resolved by power supply through other ports, the state transition does not occur and remains in UnattachWait_LB.SRC. As a result, since VBUS is not enabled, the power supply to the DRP device is not restored.

[0224] That is, unless the connection between the power bank 100 and the DRP device is physically disconnected, the DRP device cannot be recharged.

[0225] In the third embodiment, when the mobile power 100 is in UnattachWait_LB.SRC as described above, the fact that the battery 106 is charged by supplying power through another port and the "battery low" is eliminated is adopted as a transition condition from UnattachWait_LB.SRC (ST7). By adopting this third transition condition, even if the connection between the mobile power 100 and the DRP device is not physically disconnected, the power supply to the DRP device can be restored according to the state of the power supply from the external power source or the charging state of the battery 106.

[0226] Fig.19 1 is a sequence diagram showing a process sequence related to power supply and reception operations performed between the mobile power source 100 and the PC 200 according to the third embodiment. Fig.19 In the sequence diagram shown, the processing that is substantially the same as any of the above sequence diagrams is denoted by the same reference numerals. The description of the above processing will not be repeated.

[0227] refer to Fig.19 , the mobile power supply 100 switches from Unattached.SRC to Attach.SRC via AttachWait.SRC (steps S1 , S2 , S3 ), and starts supplying power to the PC 200 (step S4 ).

[0228] On the other hand, the PC 200 transitions from Unattached.SNK to Attach.SNK via AttachWait.SNK (steps S11 , S12 , S13 ), and starts receiving power from the mobile power source 100 (step S14 ).

[0229] In this way, the controller 110 of the mobile power source 100 connects the pull-up resistors 1165 and 1167 (first resistor; resistance value Rp) indicating SRC (power supply side) to the communication line, and supplies the electric power stored in the battery 106 to the connection destination.

[0230] Thereafter, when the discharge voltage of the battery 106 in the mobile power supply 100 drops to a predetermined value, the mobile power supply 100 becomes "low battery", and the discharge voltage is switched from Attach.SRC to UnattachWait_LB.SRC (step S21). In this case, the power from the mobile power supply 100 to the PC 200 is stopped. However, the mobile power supply 100 maintains the state of SRC.

[0231] On the other hand, by stopping the supply of electric power from the mobile power source 100, the PC 200 stops receiving electric power (step S15). Then, the PC 200 transitions from Attached.SNK to UnattachWait.SNK (step S16).

[0232] In this way, the controller 110 of the mobile power source 100 connects the pull-up resistors 1165 and 1167 (first resistor; resistance value Rp) indicating SRC (power supply side) to the communication line, and supplies the electric power stored in the battery 106 to the connection destination.

[0233] Furthermore, by detecting the presence of the connected mobile power source 100 , the PC 200 determines that the condition of “connection detected” is satisfied, and transitions from Unattached.SNK to AttachWait.SNK (step S31 ).

[0234] In this case, it is assumed that the mobile power supply 100 receives power via a port different from the port connected to the PC 200. That is, the mobile power supply 100 starts to receive electric power from an external power source (step S24). For example, the mobile power supply 100 may be powered by an external power source such as a power adapter 300. It is assumed that the battery 106 is charged by supplying power via other ports, and the "battery low" is eliminated.

[0235] When the "battery is low" is resolved, the mobile power 100 determines that the transition condition from UnattachWait_LB.SRC is satisfied, and switches from UnattachWait_LB.SRC to UnattachWait.SRC (step S25). In other words, the mobile power 100 waits for the connection of the device to become SNK. At this time, the mobile power 100 determines that the "sink detected" condition is satisfied by detecting that the connected PC 200 is waiting for a response from SRC, and switches from AttachWait.SRC to Attached.SRC (step S26). Under Attached.SRC, the mobile power 100 starts supplying a specified voltage to the power line.

[0236] On the other hand, the PC 200 determines that the “source detected” condition is satisfied by detecting that the connected mobile power source 100 is waiting for a response from SNK, and transitions from AttachWait.SNK to Attached.SNK (step S35 ).

[0237] When the mobile power 100 changes to Attached.SRC and the PC 200 changes to AttachWait.SNK, the mobile power 100 starts supplying power to the PC 200 (step S27 ), and the PC 200 starts receiving power from the mobile power 100 (step S26 ).

[0238] As described above, if the mobile power supply 100 is UnattachWait_LB.SRC, when "low battery" is resolved, receiving power via another port can be converted from UnattachWait_LB.SRC to AttachWait.SRC. The conversion to AttachWait.SRC will rediscover the DRP device and enable VBUS. As a result, the DRP device is converted from AttachWait.SNK to Attached.SNK, and the DRP device is recharged from the mobile power supply 100.

[0239] Therefore, when the mobile power 100 becomes rechargeable without physically disconnecting the mobile power 100 from the DRP device, power supply from the mobile power 100 to the DRP device is restored.

[0240] (e4: Operation example)

[0241] Next, according to the third embodiment, an example of power supply and reception operations performed between the mobile power source 100 and the PC 200 as an example of a DRP device will be described.

[0242] Fig. 20 2 is a schematic diagram showing an exemplary operation of power supply and reception operations performed between the mobile power source 100 and the PC 200 according to the third embodiment. Fig. 20 A shows as a comparative example an operation example when charging by an external power source is performed in the power supply and reception operation in the mobile power source 100 without adopting the conversion condition according to the third embodiment, and Fig. 20 B shows an operation example when charging by an external power source is performed in the power supply and reception operation in the mobile power source 100 in the case where the conversion condition according to the third embodiment is adopted.

[0243] In the USB Type-C standard, since a state machine is controlled for each port, a device having a plurality of ports can operate as an SRC or an SNK individually for each port.

[0244] refer to Fig. 20A, when the power supply 100 becomes "low battery" during the power supply from the mobile power supply 100 to the PC 200 without adopting the conversion condition according to the third embodiment, the power supply from the power supply 100 to the PC 200 is stopped. Here, even if power is received via another port and "low battery" is removed, the mobile power supply 100 remains in UnattachWait_LB.SRC, so the PC 200 cannot be charged.

[0245] On the other hand, reference Fig. 20 B, when the mobile power 100 becomes "low battery" during the power supply from the mobile power 100 to the PC 200 according to the third embodiment, the power supply from the mobile power 100 to the PC 200 is stopped. Here, when power is received via another port and the "low battery" is eliminated, the mobile power 100 switches to Unattached.SNK (ST4). Then, by executing a predetermined sequence, the mobile power 100 can recharge the PC 200 without disconnecting the physical connection with the PC 200.

[0246] When the mobile power supply 100 has a plurality of ports and supplies and receives power at the same time, if the received power is greater than the supplied power, the power for supplying power is supplied from the received power, and the remainder is stored in the battery 106. On the other hand, when the received power is less than the supplied power, the power for supplying power is covered by the received power and the power discharged from the battery 106.

[0247] As described above, when the mobile power 100 has a port capable of receiving power from an external power source in addition to a port for supplying power to the DRP device, the DRP device can be easily recharged by adopting the conversion condition according to the third embodiment. That is, if the "low battery" is resolved by power received via another port after the mobile power 100 becomes "low battery" by supplying power to the DRP device, the power supply from the mobile power 100 to the DRP device can be restored without physically disconnecting the mobile power 100 from the DRP device.

[0248] (e5: Processing)

[0249] Next, according to the third embodiment, a process sequence of power supply and reception operations performed between the mobile power source 100 and the PC 200 as an example of a DRP device will be described.

[0250] Fig.21 : is a flowchart showing a processing procedure related to the power supply operation of the mobile power source 100 according to the third embodiment. Fig.21The steps of the mobile power supply 100 shown are generally implemented by the firmware 114 executed as a control program by the processor 112 of the controller 110. Therefore, Fig.21 Each of the steps shown is typically performed by the processor 112 .

[0251] refer to Fig.21 , the processor 112 determines whether the discharge voltage of the battery 106 drops to a predetermined voltage while the DRP device in Attached.SRC supplies power to the DRP device (step S300). If the discharge voltage of the battery 106 does not drop to a predetermined value ("No" in step S300), the processor 112 repeats the process of step S300.

[0252] If the discharge voltage of the battery 106 has dropped to a predetermined value (YES in step S300), the processor 112 stops the power supply to the DRP device via the power line while maintaining the resistance value Rp on the communication lines (first and second communication lines 21 and 22) (step S302).

[0253] Then, the processor 112 determines whether the communication lines (the first communication line 21 and the second communication line 22) are disconnected (step S304).

[0254] If the communication line is disconnected (YES in step S304 ), processor 112 changes the resistance value shown in the communication line (first communication line 21 and second communication line 22 ) from Rp to Rd (step S306 ), and terminates the power supply operation to the DRP device.

[0255] If the communication line is not disconnected ("No" in step S304), the processor 112 determines whether the discharge voltage of the battery 106 has recovered until the discharge voltage exceeds the predetermined value (step S308). If the discharge voltage of the battery 106 has not recovered to a value exceeding the predetermined value ("No" in step S308), the processor 112 repeats the process of step S304 and subsequent steps.

[0256] If the discharge voltage of battery 106 has recovered to a value exceeding the predetermined value ("Yes" in step S308), processor 112 resumes supplying power to the DRP device via the power line (step S310). Processor 112 then repeats the processes in and after step S300.

[0257] Note that different values ​​may be used from the threshold used for comparing the discharge voltage of the battery 106 in step S300 (determination of "low battery") and the threshold used for comparing the discharge voltage of the battery 106 in step S308 (determination of recovery from "low battery"). Typically, the threshold used in step S308 is set to a value higher than the threshold used in step S300 so that oscillation does not occur.

[0258] (e6: Advantages)

[0259] In the mobile power supply 100 adopting a plurality of ports corresponding to both power supply and power reception, or in the mobile power supply 100 using an additional port for power reception, the battery of the mobile power supply 100 can be charged from another port while the connection destination DRP device is connected. In this configuration, after the mobile power supply 100 becomes "low battery" and transitions to UnattachWait_LB.SRC, if the "low battery" is resolved by power received via another port, it transitions to AttachWait.SRC.

[0260] The transition to AttachWait.SRC allows the power bank 100 to repower the DRP device using power received via another port and / or power stored in the battery 106 without disconnecting the physical connection with the DRP device.

[0261] Fourth embodiment

[0262] The above-described first to third embodiments may be appropriately combined with each other, or any modifications may be made.

[0263] For example, a configuration may be adopted in which the first switching condition adopted in the first embodiment or the second switching condition adopted in the second embodiment and the third switching condition adopted in the third embodiment are combined.

[0264] Logic that can be implemented for both the first conversion condition adopted in the first embodiment and the second conversion condition adopted in the second embodiment can be implemented, and any one of the conversion conditions can be verified according to the situation. More specifically, which conversion condition should be verified can be selected according to the type or serial number of the external device connected to the mobile power supply 100. In this case, the third conversion condition adopted in the third embodiment can be further combined.

[0265] Furthermore, as the second conversion condition, a state is illustrated in which the state (the voltage appearing in CC1 is not vRd and the voltage appearing in CC2 is not vRd) continues for more than the time (=tErrorRecovery+tDRP), but the time for continuing determination can be made longer to prevent erroneous determination.

[0266] Furthermore, in the USB Type-C standard, USB Power Delivery, which is a power supply standard for realizing electrical power exchange using a USB cable, can be used. The configurations according to the first to third embodiments are also applicable to the case where USB Power Delivery is used.

[0267] Fifth embodiment

[0268] In the above-described first to fourth embodiments, the processor 112 executes the firmware 114 to perform processing and provide functions related to the controller 110 as described above.

[0269] The firmware 114 executed by the processor 112 is a control program and can be installed or updated from the outside. For example, the firmware 114 can be stored in a non-transient (non-transient) recording medium and installed or updated (updated) to a storage area within the controller 110. As a non-temporary recording medium, an optical recording medium such as an optical disc, a semiconductor recording medium such as a flash memory, a magnetic recording medium such as a hard disk or a storage tape, or a magneto-optical recording medium such as an MO (magneto-optical disc) can be used. That is, the present embodiment may also include a computer-readable control program for implementing the processing and functions as described above, and a recording medium storing the control program.

[0270] Alternatively, the firmware 114 may be downloaded from a server device via the Internet or an intranet.

[0271] Those skilled in the art will design a controller according to the present embodiment and a device including the controller by appropriately using technology according to the age of implementing the present embodiment.

[0272] Sixth embodiment

[0273] In the first to fifth embodiments described above, the processor 112 executes the firmware 114 to implement the execution of the processing and provision of the functions related to the controller 110 as described above. However, some or all of the software may be implemented in hardware rather than in such software implementations. For hardware installation, hard-wired devices such as ASICs (Application Specific Integrated Circuits) and FPGAs (Field Programmable Gate Arrays) may be used.

[0274] Those skilled in the art will design a controller according to the present embodiment and a device including the controller by appropriately using technology according to the age of implementing the present embodiment.

[0275] According to the present embodiment, once the power supply from the power supply side to the external device is started, the power stored in the battery on the power supply side then decreases and becomes "low battery", and even if the USB cable remains connected, the roles of power supply and reception do not change. Therefore, there is no event that the electric power returns from the battery of the external device originally on the power reception side to the battery originally on the power supply side.

[0276] Although the invention made by the present inventors has been specifically described based on the embodiments, the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the gist thereof.

Claims

1. A controller for providing a port compatible with dual role power (DRP), the port being capable of being a power supply side or a power receiving side according to the Universal Serial Bus (USB) Type-C standard, the controller comprising: a state manager coupled to a power manager for controlling charging and discharging of the battery; as well as a signal transmission module for exchanging signals with a connection destination via a communication line in a USB cable according to instructions from the state manager, wherein the signal transmission module is configured to indicate whether the port is used as the power supply side or the power receiving side, and The state manager is configured as follows: supplying electric power stored in the battery to the connection destination when the port functions as the power supply side; when the condition of the battery indicates a low-battery condition, stopping the supply of electric power to the connection destination while maintaining a state in which the port functions as the power supply side; as well as When the battery is charged and the condition of supplying electric power to the connection destination is restored, supply of electric power to the connection destination is restarted according to the sequence in which the port functions as the power supply side.

2. The controller according to claim 1, wherein the signal transmission module is configured to selectively connect a first resistor or a second resistor to the communication line, the first resistor indicating the power supply side, the second resistor indicating the power receiving side, and wherein (1) when the first resistor is connected to the communication line, electric power from the battery is supplied to the connection destination, and (2) when electric power cannot be supplied to the connection destination, the state manager is configured to stop supplying electric power to the connection destination while maintaining a state in which the first resistor is connected to the communication line.

3. The controller according to claim 2, wherein when the connection with the connection destination is disconnected, the state manager instructs the second resistor of the power receiving side to be connected to the communication line instead of instructing the first resistor of the power supplying side to be connected to the communication line. 4 . The controller according to claim 3 , wherein the state manager determines that the connection with the connection destination is disconnected when the communication line is disconnected.

5. The controller according to claim 3, wherein when the controller is located on the power supply side and the connection destination is located on the power reception side, a first voltage appears on the communication line, and wherein the state manager determines that the connection with the connection destination is disconnected when a second voltage different from the first voltage appears on the communication line for a period of time exceeding a predetermined time.

6. The controller according to claim 5, wherein the predetermined time is set to be greater than or equal to the sum of a time required to keep the communication line disconnected in an error recovery state and a time required for a dual role power (DRP) switching operation. The controller according to claim 1 , wherein the signal transmission module is provided for the port.

8. The controller of claim 1, wherein the state manager is implemented by a processor executing a control program.

9. A control method for a controller, the controller providing a port compatible with dual role power (DRP), the port being capable of being a power supply side or a power receiving side according to a universal serial bus (USB) type-C standard, wherein the controller has a signal transmission module for exchanging signals with a connection destination via a communication line in a USB cable, wherein the signal transmission module is configured to indicate whether the port is used as the power supply side or the power receiving side, and The control method comprises: When the port functions as the power supply side, supplying electric power stored in a battery to the connection destination; when the condition of the battery indicates a low-battery condition, stopping the supply of electric power to the connection destination while maintaining a state in which the port functions as the power supply side; as well as When the battery is charged and the condition of supplying electric power to the connection destination is restored, supply of electric power to the connection destination is restarted according to the sequence in which the port functions as the power supply side.

10. The control method according to claim 9, wherein the signal transmission module is configured to selectively connect a first resistor or a second resistor to the communication line, the first resistor indicating the power supply side, the second resistor indicating the power receiving side, and wherein (1) when the first resistor is connected to the communication line, electric power from the battery is supplied to the connection destination, and (2) when electric power cannot be supplied to the connection destination, the control method includes: Supply of electric power to the connection destination is stopped while maintaining a state in which the first resistor is connected to the communication line.

11. A non-transitory recording medium having a control program stored thereon, the control program being executed by a processor of a controller, the controller being configured to provide a port compatible with dual role power (DRP), the port being capable of being a power supply side or a power receiving side according to a universal serial bus (USB) type-C standard, wherein the controller has a signal transmission module for exchanging signals with a connection destination via a communication line in a USB cable, wherein the signal transmission module is configured to indicate whether the port is used as the power supply side or the power receiving side, and The control program executed by the processor includes: When the port functions as the power supply side, supplying electric power stored in a battery to the connection destination; when the condition of the battery indicates a low-battery condition, stopping the supply of electric power to the connection destination while maintaining a state in which the port functions as the power supply side; as well as When the battery is charged and the condition of supplying electric power to the connection destination is restored, supply of electric power to the connection destination is restarted according to the sequence in which the port functions as the power supply side.

12. The non-transitory recording medium according to claim 11, wherein the signal transmission module is configured to selectively connect a first resistor or a second resistor to the communication line, the first resistor indicating the power supply side, the second resistor indicating the power receiving side, and wherein (1) when the first resistor is connected to the communication line, electric power from the battery is supplied to the connection destination, and (2) when electric power cannot be supplied to the connection destination, the control program executed by the processor includes: Supply of electric power to the connection destination is stopped while maintaining a state in which the first resistor is connected to the communication line.

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