Portable terminal apparatus and wireless power transmission method by portable terminal apparatus

1. A portable device-terminal comprising:

a communication transceiver configured to receive, from at least one subordinate portable terminal that operates in accordance with control performed by the portable terminal, a power transfer request signal with respect to the subordinate portable terminal;

a power transfer control circuit configured to transfer power to the subordinate portable terminal;

a battery; and

a controller configured to control an operation of the communication transceiver and an operation of the power transfer control circuit,

where the controller is further configured to:

when the communication transceiver receives the power transfer request signal, detect a battery residual amount charged in the battery, and

perform control for causing the power transfer control circuit and the communication transceiver to output electromagnetic waves for wireless power transfer in accordance with a detection result of the battery residual amount,

wherein the power transfer request signal includes a required amount of power requested by the subordinate portable device, and

wherein the controller is further configured to:

determine whether power transfer to the subordinate portable terminal can be performed based on a comparison result obtained by comparing the battery residual amount and the required amount of power with a power transfer lower allowable limit value used for determining whether the power transfer to the subordinate portable terminal can be performed,

when determining that the power transfer to the subordinate portable terminal can be performed, output a power transfer instruction signal to the power transfer control circuit,

when determining that power transfer that satisfies the required amount of power cannot be performed based on the comparison result obtained by comparing the battery residual amount and the required amount of power with the power transfer lower allowable limit value, calculate a transferrable amount of power which has a value smaller than the required amount of power and is allowable to be transferred to the subordinate portable terminal, and

control the power transfer so as to transfer the transferrable amount of power to the subordinate portable terminal.

2. The portable terminal device according to claim 1 , further comprising:

an external communication transceiver configured to receive wireless power transfer waves; and

a power reception control circuit configured to receive power with electromagnetic waves received via the external communication transceiver,

wherein the controller is further configured to:

when determining that the power transfer that satisfies the required amount of power cannot be performed, search for a wireless power transmitter that performs wireless power transfer via the external communication transreceiver,

receive power with electromagnetic waves from the wireless power transmitter as found as a result of search for the wireless power transmitter, and

perform control for causing the power reception control circuit to charge the battery by using the power as received and causing the power transfer control circuit to transmit the power in the battery to the subordinate portable terminal.

3. The portable terminal according to claim 2 , further comprising:

a wireless communication transceiver configured to communicate with an exclusive wireless power transmitter,

wherein the external communication transceiver includes a mobile communication system communication transceiver,

the wireless power transmitter includes the exclusive wireless power transmitter connected to the portable terminal via the wireless communication transceiver and a mobile wireless base station connected to the portable terminal via the mobile communication system communication transceiver, and

the controller is further configured to, when finding both the exclusive wireless power transmitter and the mobile wireless base station as a result of the search for the wireless power transmitter, perform control to transmit a power transfer request notification to the exclusive wireless power transmitter.

4. The portable terminal according to claim 2 ,

wherein the external communication transceiver is a mobile communication system communication transceiver,

wherein the wireless power transmitter is a mobile wireless base station connected to the portable terminal device via the mobile communication system communication transceiver, and

wherein the controller is further configured to, when detecting that the battery residual amount is equal to or less than a power reception start threshold used for determining start of power reception, transmit a power transfer request notification to the mobile wireless base station, and

when detecting that the battery residual amount is equal to or more than a power reception stop threshold used for determining stop of the power reception, transmit a charge completion notification to the mobile wireless base station.

5. The portable terminal according to claim 4 ,

wherein the power reception stop threshold is a value smaller than a total amount of a charge capacity of the battery and greater than the power reception start threshold.

6. A wireless power transfer method by a portable terminal, comprising the steps of:

receiving, by the portable terminal, from at least one subordinate portable terminal that operates in accordance with control by the portable terminal, a power transfer request signal with respect to the subordinate portable device terminal, the power transfer request signal including a required amount of power requested by the subordinate portable device;

detecting, by the portable terminal, a battery residual amount charged in a battery provided in the portable device terminal;

outputting, by the portable terminal, electromagnetic waves for transferring power to the subordinate portable terminal in accordance with a detection result of the battery residual amount;

determining whether power transfer to the subordinate portable terminal can be performed based on a comparison result obtained by comparing the battery residual amount and the required amount of power with a power transfer lower allowable limit value used for determining whether the power transfer to the subordinate portable terminal can be performed;

when determining that the power transfer to the subordinate portable terminal can be performed, outputting a power transfer instruction signal to the power transfer control circuit;

when determining that power transfer that satisfies the required amount of power cannot be performed based on the comparison result obtained by comparing the battery residual amount and the required amount of power with the power transfer lower allowable limit value, calculating a transferrable amount of power which has a value smaller than the required amount of power and is allowable to be transferred to the subordinate portable terminal; and

controlling the power transfer so as to transfer the transferrable amount of power to the subordinate portable terminal.

7. The wireless power transfer method according to claim 6 , further comprising:

receiving, by an external communication transceiver, wireless power transfer waves;

receiving, by a power reception control circuit, power with electromagnetic waves received via the external communication transceiver;

when determining that the power transfer that satisfies the required amount of power cannot be performed, searching for a wireless power transmitter that performs wireless power transfer via the external communication transceiver;

receiving power with electromagnetic waves from the wireless power transmitter as found as a result of search for the wireless power transmitter; and

performing control for causing the power reception control circuit to charge the battery by using the power as received and causing the power transfer control circuit to transmit the power in the battery to the subordinate portable terminal.

8. The wireless power transfer method according to claim 7 , further comprising:

communicating, by a wireless communication transceiver, with an exclusive wireless power transmitter,

wherein the external communication transceiver includes a mobile communication system communication transceiver,

wherein the wireless power transmitter includes the exclusive wireless power transmitter connected to the portable terminal via the wireless communication transceiver and a mobile wireless base station connected to the portable terminal via the mobile communication system communication transceiver, and

wherein the method further comprises when finding both the exclusive wireless power transmitter and the mobile wireless base station as a result of the search for the wireless power transmitter, performing control to transmit a power transfer request notification to the exclusive wireless power transmitter.

9. The wireless power transfer method according to claim 7 ,

wherein the external communication transceiver is a mobile communication system communication transceiver,

wherein the wireless power transmitter is a mobile wireless base station connected to the portable terminal via the mobile communication system communication transceiver,

wherein the method further comprises:

when detecting that the battery residual amount is equal to or less than a power reception start threshold used for determining start of power reception, transmitting a power transfer request notification to the mobile wireless base station; and

when detecting that the battery residual amount is equal to or more than a power reception stop threshold used for determining stop of the power reception, transmitting a charge completion notification to the mobile wireless base station.

10. The wireless power transfer method according to claim 9 ,

wherein the power reception stop threshold is a value smaller than a total amount of a charge capacity of the battery and greater than the power reception start threshold.