POWER SUPPLY APPARATUS

Abstract

A power supply apparatus requests the transmission of a requested PDO. A power receiving apparatus transmits the requested PDO in response to the request. The power supply apparatus modifies a first PDO list based on the requested PDO when it is possible to do so. The first PDO list is modified when the requested voltage is not defined in the first PDO list in a case in which a power supply circuit of the power supply apparatus is capable of supplying the request voltage indicated by the requested PDO. Subsequently, negotiation is performed based on the first PDO list thus modified.

Claims

1. A power supply method for supplying electric power from a power supply apparatus that conforms to the USB-PD specification to a power receiving apparatus, wherein the power supply apparatus is provided with a first list comprising data that defines an available voltage value and a available current value that can be supplied, wherein the power receiving apparatus is provided with a second list comprising data that defines a requested voltage value and a requested current value, and wherein the power supply method comprises: the power supply apparatus requesting the power receiving apparatus to transmit the requested voltage value; the power supply apparatus modifying the first list with reference to the requested voltage value and the first list, so as to include the requested voltage value when the requested voltage value is not defined in the first list in a case in which the power supply apparatus is capable of supplying a power supply voltage having the requested voltage value; the power supply apparatus transmitting the modified first list to the power receiving apparatus; the power receiving apparatus selecting one voltage value from the modified first list, and notifying the power supply apparatus of the selected voltage value; and the power supply apparatus supplying the power supply voltage having the selected voltage value to the power receiving apparatus.

2. The power supply method according to claim 1, further comprising, before requesting the transmission of the second list: the power supply apparatus transmitting the first list to the power receiving apparatus before modification; the power receiving apparatus selecting one voltage value from the unmodified first list, so as to notify the power supply apparatus of the selected voltage value; and the power supply apparatus supplying the power supply voltage having the selected voltage value.

3. A power supply apparatus that conforms to the USB-PD specification, structured to supply a bus voltage to a power receiving apparatus, the power supply apparatus comprising: a power supply circuit structured to generate the bus voltage that is a variable voltage; a first list comprising data that defines an available voltage value and an available current value that can be provided by means of the power supply circuit; a power supply side controller structured to communicate and negotiate with a power receiving side controller of the power receiving apparatus, to determine a voltage value to be supplied according to the first list, and to instruct the power supply circuit to generate the bus voltage having the determined voltage value; and a list modifying unit structured to request, by using a communication function of the power supply side controller, the power receiving side controller to transmit data comprising a requested voltage value, and to modify the first list so as to include the requested voltage value when the requested voltage value is not include in the first list in a case in which the power supply circuit is capable of generate the bus voltage having the requested voltage value.

4. The power supply apparatus according to claim 3, wherein, before the list modifying unit modifies the first list, the power supply side controller performs a first negotiation operation with the power receiving side controller so as to determine the voltage value to be supplied, and wherein, after the completion of the first negotiation operation, the list modifying unit requests the power receiving apparatus to transmit data including the requested voltage value.

5. The power supply apparatus according to claim 3,that conforms to the USB-PD specification.

6. The power supply apparatus according to claim 3, wherein the power supply circuit comprises a DC/DC converter structured so as to have a variable output voltage, and wherein the power supply side controller controls the output voltage of the DC/DC converter.

7. The power supply apparatus according to claim 3, wherein the power supply circuit comprises a plurality of DC/DC converters, and wherein the power supply side controller is structured to select one from among the plurality of DC/DC converters.

8. The power supply apparatus according to claim 3, wherein the power supply circuit comprises an AC/DC converter structured so as to have a variable output voltage, and wherein the power supply side controller controls the output voltage of the AC/DC converter.

9. An AC adapter comprising the power supply apparatus according to claim 3.

10. An electronic device comprising the power supply apparatus according to claim 3.

11. A control circuit for a power supply apparatus that conforms to the USB-PD specification, structured to supply a bus voltage to a power receiving apparatus, wherein the power supply apparatus comprises a power supply circuit structured to generate a variable bus voltage, in addition to the control circuit, and wherein the control circuit comprises: memory structured to store a first list comprising data that defines an available voltage and an available current that can be supplied by the power supply circuit; a power supply side controller structured to communicate with a power receiving side controller of the power receiving apparatus, to determine a voltage value to be supplied by means of negotiation using the first list, and to instruct the power supply circuit to generate the bus voltage having the determined voltage value; and a list modifying unit structured to request, by using a communication function of the power supply side controller, the power receiving side controller to transmit data inducing a requested voltage value, and to modify the first list so as to include the requested voltage value when the requested voltage is not defined in the first list in a case in which the power supply circuit is capable of supplying the bus voltage having the requested voltage value.

12. The control circuit according to claim 11, wherein, before the list modifying unit modifies the first list, the power supply side controller performs a first negotiation operation with the power receiving side controller so as to determine the voltage value to be supplied, and wherein, after the completion of the first negotiation operation, the list modifying unit requests the power receiving apparatus to transmit data including the requested voltage value.

13. The control circuit according to claim 11, monolithically integrated on a single semiconductor substrate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Embodiments will now be described, by way of example only, with reference to the accompanying drawings which are meant to be exemplary, not limiting, and wherein like elements are numbered alike in several Figures, in which:

[0044] FIG. 1 is a block diagram showing a power supply system investigated by the present inventor;

[0045] FIG. 2 is a sequence diagram showing a negotiation operation that conforms to the USB-PD specification shown in FIG. 1;

[0046] FIG. 3 is a block diagram showing a power supply system according to an embodiment;

[0047] FIG. 4 is a sequence diagram showing a negotiation operation of the power supply system shown in FIG. 3;

[0048] FIGS. 5A and 5B are diagrams for explaining the modification of a first PDO list;

[0049] FIGS. 6A through 6D are block diagrams each showing an example configuration of a power supply circuit; and

[0050] FIG. 7A is a perspective view of an AC adapter including a power supply apparatus, and FIGS. 7B and 7C are perspective views each showing an electronic device including the power supply apparatus.

DETAILED DESCRIPTION OF THE INVENTION

[0051] The invention will now be described by reference to the preferred embodiments. This does not intend to limit the scope of the present invention, but to exemplify the invention.

[0052] Description will be made below regarding preferred embodiments according to the present invention with reference to the drawings. The same or similar components, members, and processes are denoted by the same reference numerals, and redundant description thereof will be omitted as appropriate. The embodiments have been described for exemplary purposes only, and are by no means intended to restrict the present invention. Also, it is not necessarily essential for the present invention that all the features or a combination thereof be provided as described in the embodiments.

[0053] In the present specification, the state represented by the phrase “the member A is coupled to the member B” includes a state in which the member A is indirectly coupled to the member B via another member that does not substantially affect the electric connection therebetween, or that does not damage the functions or effects of the connection therebetween, in addition to a state in which the member A is physically and directly coupled to the member B.

[0054] Similarly, the state represented by the phrase “the member C is provided between the member A and the member B” includes a state in which the member A is indirectly coupled to the member C, or the member B is indirectly coupled to the member C via another member that does not substantially affect the electric connection therebetween, or that does not damage the functions or effects of the connection therebetween, in addition to a state in which the member A is directly coupled to the member C, or the member B is directly coupled to the member C.

[0055] FIG. 3 is a block diagram showing a power supply system 100 according to an embodiment. As with the configuration shown in FIG. 1, the power supply system 100 conforms to the USB Type-C specification, and includes a power supply apparatus 200 and a power receiving apparatus 300 coupled via a USB cable 106. For example, the power supply apparatus 200 is mounted on an AC adapter 102 or is mounted on an electronic device. The power supply apparatus 300 is mounted on a battery-driven electronic device 400 such as a smartphone, a tablet terminal, a digital still camera, a digital video camera, a portable audio player, or the like.

[0056] The power supply apparatus 200 includes a power supply circuit 202 that is capable of generating a variable bus voltage V.sub.BUS and a control circuit 201. The control circuit 201 includes a power supply side PD controller (which will be referred to as the “power supply side controller” hereafter) 204, memory that stores a first PDO list 206, and a list modifying unit 208. The control circuit 201 may be configured as a function IC monolithically integrated on a single semiconductor substrate. The power supply circuit 202, the power supply side controller 204, and the PDO list 206 each have the same configuration as described above with reference to FIG. 1. The PDO list 206 is stored in the memory.

[0057] The first PDO list 206 includes at least one data item (PDO) that defines a combination of an available voltage value and an available current value that can be supplied by means of the power supply circuit 202. The power supply side controller 204 is capable of communicating with a power receiving side controller 310 included in the power receiving apparatus 300. The power supply side controller 204 determines the voltage value to be supplied based on negotiation with the power receiving side controller 310 using the first PDO list 206. The power supply side controller 204 instructs the power supply circuit 202 to generate the supply voltage having the determined value.

[0058] The list modifying unit 208 requests the power receiving side controller 310 to transmit data (a requested PDO) including the voltage value requested by the power receiving apparatus 300 using the communication function of the power supply side controller 204. Under the USB-PD specification, the “get Sink capability” message makes it possible to request the transmission of such a requested PDO.

[0059] The PDO list (second PDO list) 312 of the power receiving apparatus 300 side includes two requested voltage values 20 V and 15 V. The power receiving side controller 310 selects the voltage value of 20 V, which is a preferable value (typically, a higher voltage is selected, but other criteria may be employed). Furthermore, the power receiving side controller 310 transmits the corresponding PDO as the requested PDO to the power supply side controller 204.

[0060] When the requested voltage value (20 V) indicated by the requested PDO is not defined in the first PDO list 206 in a case in which the power supply circuit 202 is capable of supplying the requested voltage (20 V), the list modifying unit 208 modifies the first PDO list 206 such that it includes the requested voltage value (20 V).

[0061] Preferably, the power supply side controller 204 performs an ordinary negotiation, i.e., the first negotiation, with the power receiving side controller 310, before the list modifying unit 208 modifies the first PDO list 206, i.e., before the “get Sink capability” message is transmitted, so as to determine the voltage value to be supplied. The power supply circuit 202 supplies the bus voltage V.sub.BUS according to the determination result. This operation is the same as described above with reference to FIG. 2. Subsequently, after the completion of the first negotiation, the list modifying unit 208 requests the power receiving apparatus 300 to transmit the requested PDO including the voltage value.

[0062] The above is the configuration of the power supply apparatus 200. Next, description will be made regarding the operation thereof.

[0063] FIG. 4 is a sequence diagram showing a negotiation operation of the power supply system 100 shown in FIG. 3. The sequence includes typical negotiation steps 5100 through 5106, which are the same as described with reference to FIG. 2. Next, the power supply apparatus 200 requests a requested PDO (S108). The power receiving apparatus 300 transmits the requested PDO in response to the request thus received (S110). The power supply apparatus 200 modifies the first PDO list 206 based on the requested PDO when it is possible (S112).

[0064] After the first PDO list 206 is modified, a negotiation operation (S114 through S120) is performed, which corresponds to Steps S110 through S106. Specifically, the power supply apparatus 200 transmits the modified first PDO list 206 to the power receiving apparatus 300 (S114). The power receiving apparatus 300 selects an optimum PDO based on the modified first PDO list (S116). Furthermore, the power receiving apparatus 300 transmits an RDO as a return value (S118). The power supply apparatus 200 sets, based on the RDO, the voltage level of the bus voltage V.sub.BUS to be generated by the power supply circuit 202 (S120).

[0065] It should be noted that, when modification of the first PDO list is impossible in Step S112, the operation is terminated in this step.

[0066] The above is the operation of the power supply system 100. Further detailed description will be made regarding the operation of the power supply system 100 with reference to specific values.

[0067] FIGS. 5A and 5B are diagrams for explaining the modification of the first PDO list. In an example shown in FIG. 5A, the requested voltage Vr is 20 V. In this example, the voltage of 20 V is defined in the first PDO list 206. In this case, the first PDO list is not modified. Thus, the voltage of 20 V is selected as a result of the first negotiation operation.

[0068] In an example shown in FIG. 5B, the first PDO list 206 is the same as that shown in FIG. 5A. However, the requested voltage Vr is 19.5 V, which differs from that shown in FIG. 5A. In this case, in the first negotiation, the voltage/current combination of 15 V and 3 A is selected. Subsequently, the first PDO list 206 is modified such that it includes the requested voltage value Vr=19.5 V, thereby generating the modified first PDO list 206′. In a case in which the allowable electric power of the power supply circuit 202 is P.sub.MAX, the current defined in the modified PDO4 may be determined based on the Expression I=P.sub.MAX/Vr.

[0069] After the modification of the first PDO list, the PDO4′ (19.5V/2.31 A) is selected from the first PDO list 206′ thus modified via the next negotiation. Thus, such an arrangement allows the power receiving apparatus 300 to operate in an optimum state (with high efficiency).

[0070] As described above, the power supply apparatus 200 according to the embodiment may be combined with various kinds of power receiving apparatuses 300, which allows an optimum bus voltage V.sub.BUS to be supplied.

[0071] FIGS. 6A through 6D are block diagrams each showing an example configuration of the power supply circuit 202. The power supply circuit 202 shown in FIG. 6A includes an AC/DC converter 202a having a variable output. The AC/DC converter 202a rectifies and smoothes an AC voltage. Furthermore, an insulation converter steps down the voltage thus rectified and smoothed, thereby generating a DC bus voltage V.sub.BUS. The insulation converter includes a variable output. The power supply side controller 204 controls the output voltage of the AC/DC converter 202a so as to obtain the requested voltage.

[0072] The power supply circuit 202 shown in FIG. 6B includes a DC/DC converter 202b having a variable output. The DC/DC converter 202b receives, as an input voltage, a DC voltage V.sub.IN supplied from a battery or otherwise generated by an unshown different DC/DC converter or AC/DC converter. The power supply side controller 204 controls the output voltage of the DC/DC converter 202b so as to obtain the requested voltage.

[0073] The power supply circuit 202 shown in FIG. 6C is configured as a combination of the AC/DC converter 202a shown in FIG. 6A and a DC/DC converter 202c having a fixed output. A selector 203 selects one from among the output voltage V.sub.DC1 of the DC/DC converter 202c and the output voltage V.sub.DC2 of the AC/DC converter 202a. The power supply side controller 204 controls the AC/DC converter 202a and the selector 203 so as to obtain the requested voltage.

[0074] The power supply circuit 202 shown in FIG. 6D has the same configuration as that shown in FIG. 6C except that the AC/DC converter 202a shown in FIG. 6C is replaced by the DC/DC converter 202b shown in FIG. 6B. The power supply side controller 204 controls the DC/DC converter 202b and the selector 203 so as to obtain the requested voltage.

[Usage]

[0075] Lastly, description will be made regarding the usage of the power supply apparatus 200. FIG. 7A is a perspective view of an AC adapter 500 including the power supply apparatus 200. The AC adapter 500 includes a housing 502, a receptacle 504, and the power supply apparatus 200. The power supply circuit 202 of the power supply apparatus 200 is configured as an AC/DC converter.

[0076] FIG. 7B is a perspective view of an electronic device 600 including the power supply apparatus 200. The electronic device 600 is configured as a device including no built-in battery, as with display apparatuses. The electronic device 600 includes a housing 602, a receptacle 604, and the power supply apparatus 200. The power supply circuit 202 of the power supply apparatus 200 is configured as an AC/DC converter.

[0077] FIG. 7C is a perspective view of an electronic device 700 including the power supply apparatus 200. The electronic device 700 is configured as a device including a built-in battery, as with laptop PCs or tablet PCs. The electronic device 700 includes a housing 702, a receptacle 704, a battery 706, and the power supply apparatus 200. The power supply circuit 202 of the power supply apparatus 200 is configured as a DC/DC converter that receives a DC voltage V.sub.BAT from the battery 706 or otherwise a DC voltage V.sub.EXT from an external AC adapter 720, and that generates the bus voltage V.sub.BUS.

[0078] As described above, the power supply apparatus 200 can be mounted on various kinds of electronic devices and AC adapters.

[0079] While the preferred embodiments of the present invention have been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the appended claims.