Power supply device

Abstract

To provide a power supply device which is convenience in a switching function of a power supply and a power reception.SOLUTION: A power supply device of an embodiment, comprises: a power supply part; a detection part; a plurality of power supply parts; and a control part. The power supply part outputs a power to a power supply line. The detection part detects an abnormality of a power output from the power supply part. Each power supply part can detach and attach an individual external device, and selectively forms a power supply state of outputting a power supplied via the power supply line to the external device to be connected and a power reception state of outputting the power supplied from the external device to be connected to the power supply line. The control part monitors a connection state of the external device to the plurality of power supply parts, and previously determines one of the power supply parts to which the external device with a power supply function is connected as a switch object. When the abnormality is not detected by the detection part, all of the plurality of power supply parts are set to a power supply state, and one power supply part as a switch object in accordance with the case where the abnormality is detected by the detection part is set to the power reception state.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] Embodiments of the present invention relate to a power supply device.

Background Art

[0002] In the USB PD (Power Delivery) standard related to USB (Universal Serial Bus), DRP (Dual Role Power) is defined. This DRP can appropriately switch between a state where a device supplies power to another device (source) and a state where it receives power from another device (sink).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem to be solved by the present invention is to provide a convenient power supply device that utilizes a power supply / power reception switching function such as DRP.

Means for Solving the Problems

[0005] The power supply device according to the embodiment includes a power supply unit, a detection unit, a plurality of power supply units, and a control unit. The power supply unit outputs power to a power supply line. The detection unit detects an abnormality in the power output from the power supply unit. The power supply unit is detachable from an individual external device, and selectively forms a power supply state in which power supplied via the power supply line is output to the connected external device, and a power reception state in which power supplied from the connected external device is output to the power supply line. The control unit monitors the connection status of external devices to the plurality of power supply units, determines one of the power supply units to which an external device having a power supply function is connected as a switching target, sets all of the plurality of power supply units to the power supply state when no abnormality is detected by the detection unit, and sets the one power supply unit determined as the switching target to the power reception state in response to an abnormality being detected by the detection unit.

Brief Description of the Drawings

[0006]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0007] Hereinafter, an example of an embodiment will be described with reference to the drawings. FIG. 1 is a block diagram showing the main circuit configuration of the power supply device 100 according to the present embodiment. The power supply device 100 supplies the power obtained from the AC power supplied from an AC power source 200 such as a commercial power supply, in-facility power supply equipment, or a power storage device, via an outlet 300 and a power cable 400, to other devices such as a battery 500, a power receiving device 600, and a power receiving device 700. Devices such as the battery 500, the power receiving device 600, and the power receiving device 700 that are power supply destinations are equipped with a power receiving function compliant with the USB PD standard. When power is supplied from the outside, the battery 500 is charged by the supplied power. When the external power supply is stopped, the battery 500 discharges the stored power. Thus, the battery 500 is also a device equipped with a power supply function. The power receiving devices 600 and 700 do not have a power supply function. In the following description, when it is not necessary to distinguish each of the battery 500, the power receiving device 600, and the power receiving device 700, they may be referred to as "USB devices". The power supply device 100 includes a power receptacle 1, a conversion circuit 2, a cutoff detection circuit 3, a power line 4, a control power supply circuit 5, a temporary power supply element 6, three power supply circuits 7, three USB receptacles 8, a control circuit 9, and a USB interface 10.

[0008] The power receptacle 1 is attached to the housing of the power supply device 100 in a state where the insertion port is exposed outside the housing. The power receptacle 1 is detachable from a power plug 401 provided at one end of the power cable 400. When the power receptacle 1 is coupled to the power plug 401, the power cable 400 and the conversion circuit 2 are electrically connected. Note that a power plug 402 provided at the other end of the power cable 400 is attached to an outlet 300 connected to the AC power source 200. Thus, when the power receptacle 1 is coupled to the power plug 401, power is supplied from the AC power source 200 to the conversion circuit 2 via the outlet 300 and the power cable 400.

[0009] The conversion circuit 2 converts the power supplied via the power receptacle 1 into power suitable for operating the internal circuit of the power supply device 100 and for USB power supply described later. For example, the conversion circuit 2 converts 100V AC power into DC power of a required voltage. The conversion circuit 2 is an example of a power supply unit.

[0010] The disconnection detection circuit 3 detects that the power output from the conversion circuit 2 to the power supply line 4 has entered a disconnected state. Then, the disconnection detection circuit 3 outputs a detection signal indicating whether or not the disconnected state is detected to the control circuit 9. The disconnection detection circuit 3 may detect a disconnected state including not only a case where the power output to the power supply line 4 is completely cut off but also a predetermined abnormal state such as a case where the power output abnormally decreases. The disconnection detection circuit 3 is an example of a detection unit.

[0011] The power supply line 4 is connected to the conversion circuit 2, the control power supply circuit 5, the temporary power supply element 6, and the power supply circuit 7. The power supply line 4 transmits the power supplied from the power supply side of the conversion circuit 2, the temporary power supply element 6, and the power supply circuit 7 to the power receiving side of the control power supply circuit 5, the temporary power supply element 6, and the power supply circuit 7. Note that the power supply side and the power receiving side change as will be described later.

[0012] The control power supply circuit 5 operates by the power supplied via the power supply line 4, obtains the power for operating the control circuit 9, and supplies the power as the power for driving the power supply device 100. The temporary power supply element 6 is charged by power supply via the power supply line 4 and outputs power to the power supply line 4 in a situation where the power supply via the power supply line 4 has stopped. The temporary power supply element 6 is, for example, a capacitor. The temporary power supply element 6 may be another power storage device such as a secondary battery. The temporary power supply element 6 is an example of a charge and discharge unit.

[0013] The power supply circuits 7 all have the same configuration and include a switch 71 and a PD controller 72. The switch 71 selectively forms a source state in which the power supplied via the power supply line 4 is transmitted to the USB receptacle 8 side and a sink state in which the power supplied from the USB receptacle 8 side is transmitted to the power supply line 4. The PD controller 72 controls the switch 71 to switch between the source state and the sink state under the control from the control circuit 9. The power supply circuit 7 is an example of a power supply unit, and here it is composed of three power supply circuits 7.

[0014] The USB receptacle 8 is attached to the housing of the power supply device 100 with the insertion port exposed outside the housing. The USB receptacle 8 is detachable from a USB plug attached to a USB device. That is, for example, in a situation where the battery 500 is attached to the power supply device 100, the USB plug 501 provided on the battery 500 is coupled to any one of the three USB receptacles 8. The three USB receptacles 8 are respectively connected to the three power supply circuits 7. When the USB receptacle 8 is coupled to the USB plug, the USB device provided with the USB plug is connected to the power supply circuit 7 and the USB interface 10.

[0015] The control circuit 9 monitors the attachment status of the USB device to the three USB receptacles 8. Then, according to the state of the detection signal given from the cutoff detection circuit 3, the control circuit 9 controls the operating states of the three power supply circuits 7 as described later. Note that the control circuit 9 outputs control signals COA, COB, COC and a role swap signal CCA as described later for controlling the operating states of the three power supply circuits 7. The control circuit 9 is an example of a control unit. The control circuit 9 includes a computer including a CPU (central processing unit) 91 and a memory 92. The CPU 91 executes information processing described later for controlling the power supply circuit 7. The memory 92 stores an information processing program describing the information processing to be executed by the CPU 91. A part of the storage area of the memory 92 is used as a work area when the CPU 91 performs information processing. Also, a part of the storage area of the memory 92 is used as a device database DBA. The device database DBA is a database for managing USB devices attached to the USB receptacle 8. The USB interface 10 is an interface unit for data communication between the USB device attached to the USB receptacle 8 and the control circuit 9.

[0016] FIG. 2 is a diagram schematically showing a configuration of one of data records REA included in the device database DBA. The device database DBA is a set of a plurality of data records REA. The data records REA are associated with respective USB devices that have been connected to the USB receptacle 8. The data record REA includes fields FAA, FAB, FAC, and FAD. In the field FAA, a device address is set as an identifier of the associated USB device. In the field FAB, function information representing functions and the like provided by the associated USB device is set. In the field FAC, a port number is set as an identifier of the USB receptacle 8 to which the associated USB device is attached. In the field FAD, a swap flag, which is flag data representing the enabled / disabled setting status of role swapping for the associated USB device, is set.

[0017] Next, the operation of the power supply device 100 configured as described above will be described. As one of the USB devices, the power supply device 100 is assumed to be used to connect the battery 500 to any one of the USB receptacles 8 and connect the power receiving devices 600 and 700 to the other USB receptacles 8. Note that the battery 500 and the power receiving devices 600 and 700 may be connected to the three USB receptacles 8 in any manner. In the following description, when it is necessary to distinguish each of the three power supply circuits 7, the power supply circuit 7 connected to the USB receptacle 8 to which the USB plug 501 of the battery 500 is coupled is denoted as the power supply circuit 7-1, the power supply circuit 7 connected to the USB receptacle 8 to which the USB plug 601 of the power receiving device 600 is coupled is denoted as the power supply circuit 7-2, and the power supply circuit 7 connected to the USB receptacle 8 to which the USB plug 701 of the power receiving device 700 is coupled is denoted as the power supply circuit 7-3.

[0018] As shown in Fig. 1, the power supply device 100 is connected to the AC power supply 200. When the conversion circuit 2 can normally output power by the supplied power from the AC power supply 200, the control power supply circuit 5 operates by the power supplied from the conversion circuit 2 via the power supply line 4. And the control circuit 9 operates by the supply of the power obtained by the control power supply circuit 5.

[0019] When the control circuit 9 is in such an operating state, the CPU 91 executes information processing for controlling the power supply circuit 7. Fig. 3 is a flowchart of the information processing by the CPU 91. Note that the content of the processing described below is an example, and changes in the order of some processing, omission of some processing, or addition of other processing are possible as appropriate.

[0020] As ACT1, the CPU 91 checks whether the cutoff state is detected by the cutoff detection circuit 3. And if the detection signal output from the cutoff detection circuit 3 represents a non-detection state, the CPU 91 determines NO and proceeds to ACT2. As ACT2, the CPU 91 checks whether a USB device is attached to the USB receptacle 8. And if the corresponding event cannot be confirmed, the CPU 91 determines NO and proceeds to ACT3. As ACT3, the CPU 91 checks whether the USB device attached to the USB receptacle 8 has been removed. And if the corresponding event cannot be confirmed, the CPU 91 determines NO and returns to ACT1. Thus, as ACT1 to ACT3, the CPU 91 waits for the cutoff state to be detected or the attachment / detachment of the USB device to be performed.

[0021] When a USB device is attached to the USB receptacle 8, the USB interface 10 detects this and notifies the control circuit 9 of the attachment detection along with the notification of the port number assigned to the corresponding USB receptacle 8. In response to this notification, the CPU 91 determines YES in ACT2 and proceeds to ACT4. As ACT4, the CPU 91 updates the device database DBA so as to manage the attachment status of the USB device after the above attachment. For example, in response to the above notification, the CPU 91 communicates with the corresponding USB device via the USB interface 10 and acquires the descriptor held by the corresponding USB device. Then, the CPU 91 checks whether the attached USB device is newly attached by comparing the information in the acquired descriptor with the device database DBA. More specifically, the CPU 91 searches the device database DBA for a data record REA in which the function information including the vendor ID, product ID, and serial number in the descriptor acquired from the USB device is set in the field FAB, and determines that it is a new attachment if there is no corresponding data record REA. In this case, the CPU 91 creates a new data record REA associated with the USB device attached this time, and updates the device database DBA to include this data record REA. At this time, the CPU 91 includes, in the function information set in the field FAB, at least the vendor ID, product ID, and serial number among the information included in the acquired descriptor, and information indicating the presence or absence of the power supply function and the power reception function. The CPU 91 also sets the port number notified from the USB interface 10 in the field FAC. The CPU 91 also sets the swap flag set in the field FAD to a state indicating that it is invalid. On the other hand, if the corresponding data record REA is found by the above search, the CPU 91 updates the device database DBA so as to set the port number notified from the USB interface 10 in the field FAC of the corresponding data record REA.

[0022] As ACT5, the CPU 91 checks whether any of the already attached USB devices has been set as a target for roll swap. For example, the CPU 91 searches the device database DBA for a data record REA in which a swap flag indicating validity is set in the field FAD. If the corresponding data record REA is not found, the CPU 91 determines that it has not been set and proceeds to ACT6 with a NO determination. As ACT6, the CPU 91 checks whether the USB device attached this time is a device with a power supply function. For example, if the descriptor obtained as described above contains information indicating that it has a power supply function, the CPU 91 determines YES and proceeds to ACT7.

[0023] As ACT7, the CPU 91 enables roll swap of the power supply circuit 7 connected to the USB receptacle 8 to which the USB device has been attached this time. That is, the CPU 91 changes the control signal given to the power supply circuit 7 connected to the USB receptacle 8 to which the port number notified from the USB interface 10 has been assigned to a state indicating validity. Further, the CPU 91 updates the swap flag set in the field FAD of the data record REA that was the target of the update in ACT4 to a state indicating validity. Then, the CPU 91 returns to the waiting state of ACT1 to ACT3 after that.

[0024] If the CPU 91 finds the corresponding data record REA through the search in ACT5, it determines YES assuming it has been set, and returns to the waiting state of ACT1 to ACT3 without performing ACT6 and ACT7. Also, if the descriptor obtained as described above does not contain information indicating that the USB device has a power supply function, the CPU 91 determines NO in ACT6, assuming that the USB device attached this time does not have a power supply function, and returns to the waiting state of ACT1 to ACT3 without performing ACT7. That is, the CPU 91 sets the power supply circuit 7 to which the USB device attached this time is connected as the target for roll swap only when none of the power supply circuits 7 to which the USB device is already connected are set as the target for roll swap and the USB device attached this time has a power supply function.

[0025] As an example, when no USB device is connected to each power supply circuit 7 and a power receiving device 600 is connected to the power supply circuit 7-2, the CPU 91 determines NO in ACT5 and NO in ACT6, and does not execute ACT7. Therefore, the power supply circuit 7-2 is not targeted for roll swap. In the initial state, the CPU 91 sets each control signal COA, COB, COC to a state indicating invalid. At this time, the CPU 91 keeps the control signal COB in the state indicating invalid.

[0026] As an example, when a power receiving device 600 is already attached and a battery 500 is connected to the power supply circuit 7-1, the CPU 91 determines NO in ACT5 and YES in ACT6, and executes ACT7. Therefore, the power supply circuit 7-1 is targeted for roll swap. At this time, the CPU 91 sets the control signal COA to a state indicating valid.

[0027] As an example, when a power receiving device 700 is connected to the power supply circuit 7-3 with the battery 500 and the power receiving device 600 already attached, the CPU 91 determines YES at ACT5 and does not execute ACT7. Therefore, the power supply circuit 7-3 is not subject to role swap. And at this time, the CPU 91 sets the control signal COC to a state indicating invalidity.

[0028] As an example, when a USB device (not shown) having a power supply function is attached to the power supply circuit 7-3 with the battery 500 and the power receiving device 600 already attached, the CPU 91 determines YES at ACT5 and does not execute ACT7. Therefore, even when a USB device having a power supply function is connected, the power supply circuit 7-3 is not subject to role swap. As described above, a plurality of the three power supply circuits 7 are not simultaneously subject to role swap.

[0029] When a USB device is removed from the USB receptacle 8, the USB interface 10 detects this and notifies the control circuit 9 of the removal detection along with the notification of the port number assigned to the corresponding USB receptacle 8. In response to this notification, the CPU 91 determines YES at ACT3 and proceeds to ACT8. As ACT8, the CPU 91 updates the device database DBA so as to manage the attachment status of the USB device after the above removal. That is, for example, the CPU 91 searches the device database DBA for the data record REA in which the notified port number is set in the field FAC. And the CPU 91 sets a predetermined invalid value in the field FAC of the corresponding data record REA. Thus, a valid port number is set in the field FAC of the data record REA only when the associated USB device is attached to any of the USB receptacles 8.

[0030] As ACT9, the CPU 91 checks whether the role swap of the power supply circuit 7 connected to the USB receptacle 8 from which the USB device has been removed is set to be effective. For example, if the swap flag set in the field FAD of the data record REA that was the update target in ACT8 represents an effective state, the CPU 91 determines YES and proceeds to ACT10.

[0031] As ACT10, the CPU 91 invalidates the role swap of the corresponding power supply circuit 7. That is, the CPU 91 changes the control signal given to the power supply circuit 7 connected to the USB receptacle 8 to which the port number notified from the USB interface 10 is assigned to a state representing invalidation. Also, the CPU 91 updates the swap flag set in the field FAD of the data record REA that was the update target in ACT8 to a state representing invalidation. As ACT10, after the CPU 91 invalidates the role swap of the corresponding power supply circuit 7, it proceeds to ACT11.

[0032] As ACT11, the CPU 91 checks whether there is a device with a power supply function among the USB devices attached to the USB receptacle 8. For example, the CPU 91 searches the device database DBA for a data record REA in which the port number assigned to any USB receptacle 8 is set in the field FAC and the function information including information indicating that it has a power supply function is set in the field FAB. If the CPU 91 finds the corresponding data record REA, it determines YES, assuming that there is a USB device with a power supply function, and proceeds to ACT12.

[0033] As ACT12, the CPU 91 selects one of the power supply circuits 7 to which a USB device with a power supply function is connected. When USB devices with a power supply function are connected to both of the two power supply circuits 7, the CPU 91 selects one according to a predetermined rule. It is assumed that the rule is determined, for example, as "select the power supply circuit 7 connected to the USB receptacle 8 to which a smaller port number is assigned." Note that the rule may be appropriately determined by the designer or user of the power supply device 100 or the like.

[0034] As ACT13, the CPU 91 enables the role swap of the power supply circuit 7 selected in ACT12. That is, the CPU 91 changes the control signal given to the power supply circuit 7 selected in ACT12 to a state indicating valid. Further, with respect to the data record REA in which the port number assigned to the USB receptacle 8 to which the power supply circuit 7 selected in ACT12 is connected is set in the field FAC, the CPU 91 updates the swap flag set in the field FAD to a state indicating valid. Then, the CPU 91 returns to the waiting state of ACT1 to ACT3 after that.

[0035] Note that if the swap flag set in the field FAD of the data record REA that was the update target in ACT8 indicates invalid, the CPU 91 determines NO assuming that the role swap is invalid in ACT9, and returns to the waiting state of ACT1 to ACT3 without executing ACT10 and subsequent steps. Also, if the CPU 91 does not find the corresponding data record REA by the above-described search in ACT11, it determines NO and returns to the waiting state of ACT1 to ACT3 without executing ACT12 and ACT13. That is, in these cases, the CPU 91 does not enable a new role swap.

[0036] For example, when the power supply from the AC power source 200 is cut off or the like and the power output of the conversion circuit 2 enters a cut-off state, the cut-off detection circuit 3 detects this and changes the detection signal to a state indicating detection. In response to this, the CPU 91 determines YES at ACT1 and proceeds to ACT14. At ACT14, the CPU 91 executes a roll swap. For example, the CPU 91 outputs a trigger pulse as a roll swap signal CCA. When the PD controller 72 in the power supply circuit 7 receives the trigger pulse as the roll swap signal CCA, it changes the state of the switch 71 only when the input control signal represents an effective state. That is, the corresponding PD controller 72 changes the switch 71 from the source state to the sink state. In response to this, the corresponding power supply circuit 7 enters a state of outputting the power supplied from the connected USB device to the power line 4.

[0037] As an example, if the control signal COA represents an effective state as described above, the PD controller 72 of the power supply circuit 7-1 sets the switch 71 to the sink state. On the other hand, since the battery 500 can no longer receive power supply via the USB plug 501, it starts to output power. Thus, power is supplied from the battery 500 to the temporary power supply element 6, the power supply circuits 7-2 and 7-3, and the control power supply circuit 5 via the USB plug 501, the USB receptacle 8, the power supply circuit 7-1, and the power line 4. That is, the power supply device 100 continues to operate, and the power supply to the power receiving devices 600 and 700 continues. In the case of this example, since the control signals COB and COC represent an ineffective state, the power supply circuits 7-2 and 7-3 do not respond to the trigger pulse. After executing the roll swap at ACT14, the CPU 91 proceeds to ACT15.

[0038] At ACT15, the CPU 91 waits for the power output from the conversion circuit 2 to recover from the cut-off state. When the cut-off detection circuit 3 no longer detects the cut-off state and changes the detection signal to a state indicating non-detection, the CPU 91 determines YES and proceeds to ACT16.

[0039] As ACT16, the CPU 91 executes a role swap in the same way as ACT14. Then, the PD controller 72 provided in the power supply circuit 7 to which a control signal indicating validity is applied returns the state of the switch 71 from the sink state to the source state. As a result, power supply is resumed from the conversion circuit 2 via the power supply line 4 to the temporary power supply element 6, the power supply circuits 7-1, 7-2, 7-3, and the control power supply circuit 5. After this, the CPU 91 returns to the standby state of ACT1 to ACT3.

[0040] Figure 4 is a time chart showing how the role swap is performed. At time ta, as shown in FIG. 1, the battery 500 and the power receiving devices 600 and 700 are attached, and as described above, the role swap of the power supply circuit 7-1 is set to be valid, and the power output from the conversion circuit 2 is normal. At this time, the power supply circuits 7-1, 7-2, and 7-3 are all in the source state, and the power supplied from the conversion circuit 2 via the power supply line 4 is supplied to each device.

[0041] At time tb, the power output from the conversion circuit 2 is cut off. At this time, since the power supply circuits 7-1, 7-2, and 7-3 are all in the source state and do not output power to the power supply line 4, discharge occurs from the temporary power supply element 6, preventing a rapid voltage drop in the power supply line 4. As a result, the power supply circuits 7-1, 7-2, 7-3, and the control circuit 9 can continue to operate. However, the output voltage of the temporary power supply element 6 gradually decreases with the discharge, and the voltage of the power supply line 4 also decreases accordingly. At time tc, the cutoff detection circuit 3 detects that the power output from the conversion circuit 2 has been cut off, and the state of the detection signal has changed from undetected to detected. In response to this, a trigger pulse TP is output as the role swap signal CCA.

[0042] At time point td, the switching of switch 71 by the PD controller 72 of the power supply circuit 7-1 in response to the trigger pulse TP is completed, and the power supply circuit 7-1 has switched to the sink state. Accordingly, the battery 500 has switched from the charging state to the discharging state. The power supply circuits 7-2 and 7-3 do not switch because the control signals COB and COC represent the invalid state, and they maintain the source state. In response to the start of discharging from the battery 500 at time point td, the voltage of the power supply line 4 starts to rise, and the voltage of the power supply line 4 is stable at time point te. At this time, the voltage of the temporary power supply element 6 also rises in the same manner as the voltage of the power supply line 4.

[0043] As described above, the power supply device 100 monitors the connection status of the USB device to the three power supply circuits 7, and effectively sets the roll swap of only one of the power supply circuits 7 to which the USB device having the power supply function is connected. Then, in response to the power output from the conversion circuit 2 to the power supply line 4 being in the cut-off state, the power supply device 100 executes the roll swap only with one power supply circuit 7 for which the roll swap is effectively set. Thus, according to the power supply device 100, if the user attaches a USB device having a power supply function such as the battery 500 to one of the three USB receptacles 8, when an abnormality occurs in the power supply from the conversion circuit 2, it is possible to continue the power supply by the power supply from the USB device. Since the user can attach the USB device having the power supply function to any of the three USB receptacles 8, the attachment work of the USB device becomes easy.

[0044] Also, even if the user attaches a USB device having a power supply function to a plurality of USB receptacles 8, the plurality of power supply circuits 7 do not simultaneously enter the sink state. Therefore, according to the power supply device 100, an unstable operating state in which power is received from a plurality of USB devices simultaneously does not occur, and the burden on the user regarding the attachment of the USB device to the power supply device 100 is further reduced.

[0045] Also, when a USB device connected to the power supply circuit 7 with roll swap effectively set is removed, the power supply device 100 invalidates the roll swap for the corresponding power supply circuit 7. And if another USB device already attached has a power supply function, the power supply device 100 effectively sets the roll swap for the power supply circuit 7 to which the USB device is connected. Thus, according to the power supply device 100, in the corresponding case, it is possible to automatically continue the state where the power supply operation by power supply from the USB device can be continued, and there is no need for user operation therefor.

[0046] Also, after the power output from the conversion circuit 2 to the power line 4 is cut off, until the power supply from the USB device becomes stable, a time lag occurs, for example, from the time point tb to the time point te in FIG. 4. However, due to the discharge from the temporary power supply element 6, the power supply can be continued even during the above time lag. Thereby, the FRS (fast role swap) specification in the USB PD standard can be satisfied. Note that the storage capacity of the temporary power supply element 6 is preferably determined so that the discharge can be continued at least at a predetermined voltage during the above time lag.

[0047] This embodiment can be variously modified as follows. The conversion circuit 2 may be configured to receive the supply of DC power from the outside of the power supply device 100. Alternatively, the conversion circuit 2 may be configured to receive power from a power source such as a battery provided in the power supply device 100. Alternatively, a power source such as a battery may be provided instead of the conversion circuit 2.

[0048] The cutoff detection circuit 3 may also detect the cutoff state of the power supplied to the conversion circuit 2.

[0049] Instead of outputting a detection signal, the interruption detection circuit 3 may output a roll swap signal CCA, and a trigger pulse may be generated in this roll swap signal CCA in response to detecting an interrupted state. In this case, the CPU 91 does not perform ACT1 and ACT14 to ACT16 in FIG. 3.

[0050] Two or four or more power supply circuits 7 may be provided in the power supply device 100.

[0051] The power supply device 100 may not conform to the USB PD standard. In this case, the device to be attached does not have to be a USB device, and the USB receptacle 8 may also be replaced with a receptacle or plug conforming to another connector standard.

[0052] If the time lag from when the power output from the conversion circuit 2 to the power supply line 4 is interrupted until the power supply from the USB device becomes stable is shorter than the allowable time defined by the FRS specification, or if it is not necessary to satisfy the FRS specification, the temporary power supply element 6 may be omitted.

[0053] One of the power supply circuits 7 may be designated by operating a user interface device additionally provided in the power supply device 100 or a user interface device external to the power supply device 100, and the roll swap of the designated power supply circuit 7 may be set to be enabled.

[0054] Each function realized by the CPU 91 through information processing may also be realized by hardware that executes information processing not based on a program such as a logic circuit. Also, each of the above functions may be realized by combining software control with hardware such as the above logic circuit.

[0055] Although some embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.

Explanation of Reference Numerals

[0056] 1…Power receptacle, 2…Conversion circuit, 3…Interruption detection circuit, 4…Power line, 5…Control power circuit, 6…Temporary power supply element, 7(7-1,7-2,7-3)…Power supply circuit, 8…USB receptacle, 9…Control circuit, 10…USB interface, 71…Switch, 72…PD controller, 91…CPU, 92…Memory, 100…Power supply device, 200…AC power supply, 300…Outlet, 400…Power cable, 401,402…Power plug, 500…Battery, 501,601,701…USB plug, 600,700…Power receiving device.

Claims

1. A power supply unit that outputs power to a power line; A detection unit that detects an abnormality in the power output from the power supply unit; A plurality of power supply units that can be attached to and detached from individual external devices, and selectively form a power supply state in which power is output to the connected external device via the power line and a power reception state in which power supplied from the connected external device is output to the power line; A control unit that monitors the connection status of external devices to the plurality of power supply units, determines one of the power supply units to which an external device having a power supply function is connected as a switching target, sets all of the plurality of power supply units to the power supply state when no abnormality is detected by the detection unit, and sets the one power supply unit determined as the switching target to the power reception state in response to the detection of an abnormality by the detection unit; A power supply device comprising the above.

2. A charge and discharge unit that is charged by the power supplied via the power line and discharges to the power line when power supply via the power line is not performed; The power supply device according to claim 1, further comprising the above.

3. The charge and discharge unit has a charge capacity that allows discharge during a period from when an abnormality occurs in the power output from the power supply unit until the power output from the power supply unit set to the power reception state by the control unit starts; The power supply device according to claim 2.

4. If the external device having a power supply function is not connected to the one power supply unit determined as the switching target, the control unit re-determines the power supply unit to be switched; The power supply device according to claim 1 or claim 2.

5. The plurality of power supply units comply with the USB Power Delivery standard; The power supply device according to any one of claims 1 - 4.

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