POWER TRANSMISSION DEVICE AND WAVEFORM MONITOR CIRCUIT FOR USE IN POWER TRANSMISSION DEVICE

• US 20130020879A1
• Filed: 09/27/2012
• Published: 01/24/2013
• Est. Priority Date: 03/29/2010
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Suzuki, Kazuhiro, Kihara, Hideyuki, Ohta, Kazuyo, Kada, Kyohei, Matsumoto, Takaoki
• Granted Patent: US 9,306,400 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 5/266 One coil at each side, e.g. with primary and secondary coils
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

A power transmission device in a power transmission system including the power transmission device including a primary coil and a power reception device including a secondary coil, the primary coil being electromagnetically coupled to the secondary coil, to receive in the power reception device AC power transmitted from the power transmission device, comprises a waveform monitor circuit configured to detect an electric potential at one end of the primary coil and output a waveform monitor signal formed by restricting the detected electric potential to an electric potential which is equal to or higher than a ground electric potential; a waveform detection circuit configured to detect a waveform change in the waveform monitor signal input from the waveform monitor circuit; and a data detection circuit configured to detect data transmitted by load change by a load modulation unit in the power reception device based on a result of detection of the waveform change detected by the waveform detection circuit.

Claims

1. A power transmission device in a power transmission system including the power transmission device including a primary coil and a power reception device including a secondary coil, the primary coil being electromagnetically coupled to the secondary coil, to receive in the power reception device AC power transmitted from the power transmission device, the power transmission device comprising:

a waveform monitor circuit configured to detect an electric potential at one end of the primary coil, the electric potential being changeable by load modulation by a load modulation unit in the power reception device, and output a waveform monitor signal formed by restricting the detected electric potential to an electric potential which is equal to or higher than a reference electric potential;

a waveform detection circuit configured to detect a waveform change in the waveform monitor signal input from the waveform monitor circuit; and

a data detection circuit configured to detect data transmitted to the power transmission device by load change by the load modulation unit in the power reception device based on a result of detection of the waveform change detected by the waveform detection circuit.

2. The power transmission device according to claim 1,

wherein the waveform monitor circuit includes:

a rectification circuit including a diode provided between one end of the primary coil and an input end of the waveform detection circuit such that a direction from the one end of the primary coil to the input end of the waveform detection circuit is a forward direction; and

a first resistor, one end of which is connected onto a signal line between a cathode side of the diode and the input end of the waveform detection circuit, and the other end of which is connected to a ground terminal held at a ground electric potential.

3. The power transmission device according to claim 2,

wherein the rectification circuit further includes a second resistor provided between the cathode side of the diode and the ground terminal.

4. The power transmission device according to claim 2,

wherein the rectification circuit further includes a second resistor provided between the one end of the primary coil and an anode side of the diode.

8. The power transmission device according to claim 2,

wherein the diode is a Schottky barrier diode.

9. The power transmission device according to claim 2,

wherein the diode is a zener diode.

5. A power transmission device in a power transmission system including the power transmission device including a primary coil and a power reception device including a secondary coil, the primary coil being electromagnetically coupled to the secondary coil, to receive in the power reception device AC power transmitted from the power transmission device, the power transmission device comprising:

a waveform monitor circuit configured to detect an electric potential at one end of the primary coil, and output a waveform monitor signal formed by restricting the detected electric potential to an electric potential which is equal to or higher than a reference electric potential;

a waveform detection circuit configured to detect a waveform change in the waveform monitor signal input from the waveform monitor circuit; and

a data detection circuit configured to detect data transmitted by load change by a load modulation unit in the power reception device based on a result of detection of the waveform change detected by the waveform detection circuit

wherein the waveform monitor circuit includes;

a rectification circuit including a diode provided between the one end of the primary coil and an input end of the waveform detection circuit such that a direction from the one end of the primary coil toward the input end is a forward direction, and a second resistor provided at an anode side of the diode;

a first resistor, one end of which is connected onto a signal line between the anode side of the diode and the second resistor, and the other end of which is connected to a ground terminal held at a ground electric potential; and

a third resistor, one end of which is connected to a cathode side of the diode and the other end of which is connected to a ground terminal held at a ground electric potential.

6. The power transmission device according to claim 5,

wherein the rectification circuit further includes a fourth resistor provided between the cathode side of the diode and the input end of the waveform detection circuit.

7. The power transmission device according to claim 5,

wherein the rectification circuit further includes a fifth resistor provided between the anode side of the diode and the second resistor.

12. The power transmission device according to claim 5, wherein the diode is a Schottky barrier diode.

13. The power transmission device according to claim 5, wherein the diode is a zener diode.

10. A waveform monitor circuit provided in a power transmission device in a power transmission system including the power transmission device including a primary coil and a power reception device including a secondary coil, the primary coil being electromagnetically coupled to the secondary coil, to receive in the power reception device AC power transmitted from the power transmission device, the waveform monitor circuit comprising:

a rectification circuit provided between one end of the primary coil and an input end of the waveform detection circuit such that a direction from the one end of the primary coil to the input end of the waveform detection circuit is a forward direction; and

a first resistor, one end of which is connected onto a signal line between an output end of the rectification circuit and the input end of the waveform detection circuit, and the other end of which is connected to a ground terminal held at a ground electric potential.

11. A waveform monitor circuit provided in a power transmission device in a power transmission system including the power transmission device including a primary coil and a power reception device including a secondary coil, the primary coil being electromagnetically coupled to the secondary coil, to receive in the power reception device AC power transmitted from the power transmission device, the waveform monitor circuit comprising:

a rectification circuit including a diode provided between one end of the primary coil and an input end of the waveform detection circuit such that a direction from the one end of the primary coil to the input end of the waveform detection circuit is a forward direction, and a second resistor provided at an anode side of the diode;

a first resistor, one end of which is connected onto a signal line between an anode side of the diode and the second resistor, and the other end of which is connected to a ground terminal held at a ground electric potential; and

a third resistor one end of which is connected to a cathode side of the diode and the other end of which is connected to a ground terminal held at a ground electric potential.