POWER RECEPTION DEVICE AND ELECTRONIC APPARATUS

• US 20150042170A1
• Filed: 06/28/2013
• Published: 02/12/2015
• Est. Priority Date: 12/06/2012
• Status: Active Grant

• Current Assignee: Tokin Corporation (Yageo Corporation)
• Original Assignee: NEC Tokin Corporation (Yageo Corporation)
• Inventors: Makita, Kazumasa
• Granted Patent: US 9,837,858 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H04B 5/72 for local intradevice communication
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

A power reception device includes a power reception antenna, a rectifier circuit, a communication section, a switch and a switch control section. The rectifier circuit converts electric power received by the power reception antenna into direct current voltage. The communication section communicates via the power reception antenna. The switch is connected between the power reception antenna and the communication section. The switch can transition between a conductive state where the communication section is electrically connected to the power reception antenna and a cut-off state where the communication section is electrically disconnected from the power reception antenna. The switch control section performs transition of the switch into the cut-off state when the direct current voltage exceeds a first threshold. The switch control section performs transition of the switch into the conductive state when the direct current voltage falls below a second threshold different from the first threshold.

Claims

1. A power reception device comprising:

a power reception antenna used for both communication and electric power reception;

a rectifier circuit connected to the power reception antenna, wherein the rectifier circuit converts, into direct current voltage, electric power received by the power reception antenna, and the direct current voltage is output and supplied to a load;

a communication section which communicates via the power reception antenna;

a switch connected between the power reception antenna and the communication section, wherein the switch is transitable between a conductive state where the communication section is electrically connected to the power reception antenna and a cut-off state where the communication section is electrically disconnected from the power reception antenna; and

a switch control section connected to the rectifier circuit, wherein the switch control section performs transition of the switch into the cut-off state when the direct current voltage output from the rectifier circuit exceeds a first threshold in association with start of the electric power reception by the power reception antenna, and the switch control section performs transition of the switch into the conductive state when the direct current voltage falls below a second threshold different from the first threshold.

2. The power reception device as recited in claim 1, wherein:

when the power reception antenna starts the electric power reception, the direct current voltage output from the rectifier circuit reaches, through a maximum value, a supplied value smaller than the maximum value; and

the first threshold is larger than the supplied value and smaller than the maximum value.

3. The power reception device as recited in claim 2, wherein the second threshold is smaller than the supplied value.

4. The power reception device as recited in claim 1, wherein:

during signal sending by the communication section via the power reception antenna, the switch control section does not perform the transition of the switch into the cut-off state even if the direct current voltage output from the rectifier circuit exceeds the first threshold; and

the switch control section performs the transition of the switch into the cut-off state if the direct current voltage exceeds a third threshold larger than the first threshold.

5. The power reception device as recited in claim 4, wherein the communication section notifies the switch control section, by a control signal, that the signal sending via the power reception antenna is performed.

6. The power reception device as recited in claim 1, wherein:

the power reception device is configured to perform communication with load modulation by using the power reception antenna; and

during performance of the communication with load modulation, the switch control section performs the transition of the switch into the cut-off state under a case where the direct current voltage exceeds the first threshold.

7. The power reception device as recited in claim 1, wherein the power reception device further comprises a DC-DC converter connected between the rectifier circuit and the load.

8. The power reception device as recited in claim 1, wherein:

the switch includes an in-line switch and a ground switch;

the in-line switch is connected in series between the power reception antenna and the communication section; and

the ground switch is connected between a connection point, which is between the power reception antenna and the communication section, and ground.

9. The power reception device as recited in claim 8, wherein each of the in-line switch and the ground switch is formed of an N-channel FET.

10. An electronic apparatus comprising:

the power reception device as recited in claim 1; and

a load to which the direct current voltage output from the rectifier circuit of the power reception device is supplied.