Electronic device

• US 20080197711A1
• Filed: 02/12/2008
• Published: 08/21/2008
• Est. Priority Date: 02/20/2007
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group), Sony Ericsson Mobile Communications Japan Incorporated (Sony Group Corp.)
• Original Assignee: Seiko Epson Corporation (Seiko Group), Sony Ericsson Mobile Communications Japan Incorporated (Sony Group Corp.)
• Inventors: Suzuki, Katsuya, Yamazaki, Manabu, Onishi, Kota, Kato, Hiroshi, Suzuki, Kuniharu, Yoda, Kentaro
• Granted Patent: US 7,999,417 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 7/00308 Overvoltage protection
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices

Abstract

An electronic device having at least a loop-shaped electric conductor generating electric power by electromagnetic induction is provided. The electronic device includes a voltage-detecting unit, a voltage-comparing unit and a separating unit. The voltage-detecting unit is configured to detect a voltage generated in the electric conductor by the electromagnetic induction. The voltage-comparing unit is configured to make a comparison between the voltage detected by the voltage-detecting unit and a predetermined reference voltage and determining whether the voltage detected by the voltage-detecting unit exceeds the predetermined reference voltage. The separating unit is configured to break an electric connection between the electronic conductor and an electronic circuit connecting to the electric conductor when the voltage-comparing unit determines that the voltage detected by the voltage-detecting unit exceeds the predetermined reference voltage.

Claims

1. An electronic device having at least a loop-shaped electric conductor generating electric power by electromagnetic induction, comprising:

a voltage-detecting unit configured to detect a voltage generated in the electric conductor by the electromagnetic induction;

a voltage-comparing unit configured to make a comparison between the voltage detected by the voltage-detecting unit and a predetermined reference voltage and determining whether the voltage detected by the voltage-detecting unit exceeds the predetermined reference voltage; and

a separating unit configured to break an electric connection between the electronic conductor and an electronic circuit connecting to the electric conductor when the voltage-comparing unit determines that the voltage detected by the voltage-detecting unit exceeds the predetermined reference voltage.

2. A electronic device according to claim 1, further comprising:

a power-accumulating unit configured to accumulate electric power generated from the electric conductor within a time period from the voltage detected by the voltage-detecting unit exceeding the predetermined reference voltage to the separating unit breaking the electric connection between the above electric conductor and the electronic circuit.

3. A electronic device according to claim 2, further comprising:

a rectifying unit configured to convert an alternating voltage generated in the electric conductor by the electromagnetic induction to a direct current voltage, wherein

the power-accumulating unit is a direct-current capacitor provided between the rectifying unit and the electronic circuit.

4. A electronic device according to claim 1, further comprising:

a voltage-dividing unit configured to divide the voltage generated in the electric conductor by the electromagnetic induction at a predetermined ratio, wherein

the voltage-detecting unit detects the voltage divided by the voltage-dividing unit, and the voltage-comparing unit makes a comparison between the divided voltage detected by the voltage-detecting unit and the predetermined reference voltage.

5. The electronic device according to claim 1, wherein

the electric conductor includes

a power-transmission electric conductor for carrying out noncontact power transmission using electromagnetic induction;

and a voltage-detection electric conductor for supplying the voltage generated from the electromagnetic induction to the voltage-detecting unit.

6. A electronic device according to claim 5,

wherein at least the power-transmission electric conductor is a planar coil formed by spirally winding a linear conductor, and

wherein the voltage-detection electric conductor is a planar coil formed of at least a loop-shaped linear conductor sharing a common central axis with the planar coil of the power-transmission electric conductor.

7. A electronic device according to claim 5,

wherein at least the power-transmission electric conductor is a planar coil formed by spirally winding a linear conductor, and

wherein the voltage-detection electric conductor is a planar coil formed of at least a loop-shaped linear conductor sharing a part of the linear conductor that forms a planner coil of the power-transmission electric conductor with the power-transmission electric conductor.

8. A electronic device according to claim 5, further comprising:

a voltage-dividing unit configured to divide the voltage generated in the voltage-detection electric conductor by the electromagnetic induction at the predetermined ratio, wherein

the voltage-detecting unit detects the voltage divided by the voltage-dividing unit, and

the voltage-comparing unit makes a comparison between the divided voltage detected by the voltage-detecting unit and the predetermined reference voltage.

9. A electronic device according to claim 1,

wherein the separating unit includes a switching circuit configured to make a switch of electric conduction state/non-conduction state between the electric conductor and the electronic circuit, and

wherein the voltage-comparing unit outputs a switching signal, for switching the electrical connection between the electric conductor and the electronic circuit to the non-conduction state, to the switching circuit, when the voltage detected by the voltage-detecting unit exceeds the predetermined reference voltage.

10. A electronic device according to claim 9,

wherein the switching circuit of the separating unit includes a first switching circuit connected between the electric conductor and the electronic circuit and a second switching circuit for making a switch of electric conduction state/non-conduction state by the first switching circuit, and

wherein the voltage-comparing unit outputs a switching signal, for switching the electrical connection caused by the first switching circuit to the non-conduction state, to the second switching circuit when the voltage detected by the voltage-detecting unit exceeds the predetermined reference voltage.