DEVICE HOUSING A BATTERY AND CHARGING PAD

• US 20110128714A1
• Filed: 11/26/2010
• Published: 06/02/2011
• Est. Priority Date: 11/27/2009
• Status: Active Grant

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: TERAO, Kyozo, Toya, Shoichi
• Granted Patent: US 8,519,666 B2
• Time in Patent Office: Days
• US Class Current: 361/807
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• 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: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/00302 Overcharge protection
• CPC Class Codes: H02J 7/0044 specially adapted for holding portable devices containing batteries H02J7/0045 takes precedence

Abstract

A charging pad 10 is provided with a power supply coil 11, and a device housing a battery 50 containing an induction coil 51. A device housing a battery 50 is provided with a rectifying circuit 53 that rectifies AC power induced in the induction coil 51, a charging circuit 54 that charges the internal battery 52 with output from the rectifying circuit 53, a shorting circuit 56 that short circuits the terminals of the induction coil 51, and a control circuit 57 that controls the shorting circuit 56 ON when a charging abnormality is detected. If the control circuit 57 detects a charging abnormality during power transmission from the charging pad 10 power supply coil 11 to the device housing a battery 50 induction coil 51, it controls the shorting circuit 56 ON to cut-off the supply of power from the induction coil 51 to the rectifying circuit 53.

Claims

1. A device housing a battery and charging pad comprising:

a charging pad provided with a power supply coil; and

a device housing a battery containing an induction coil that magnetically couples with the power supply coil,

wherein power transmitted from the power supply coil to the induction coil is used to charge the internal battery contained in the device housing a battery,

wherein the device housing a battery comprises;

a rectifying circuit that rectifies AC power induced in the induction coil;

a charging circuit that charges the internal battery contained in the device housing a battery with output from the rectifying circuit;

a shorting circuit that short circuits the terminals of the induction coil; and

a control circuit that controls the shorting circuit ON when a charging abnormality is detected,

wherein the control circuit detects a charging abnormality during power transmission from the charging pad power supply coil to the device housing a battery induction coil, and controls the shorting circuit ON to cut-off the supply of power from the induction coil to the rectifying circuit.

2. The device housing a battery and charging pad as cited in claim 1 wherein the rectifying circuit is a synchronous rectifying circuit.

3. The device housing a battery and charging pad as cited in claim 2 wherein the synchronous rectifying circuit is provided with a FET bridge circuit, and FETs in the FET bridge circuit serve a dual purpose as the shorting circuit.

4. The device housing a battery and charging pad as cited in claim 1 wherein the shorting circuit short circuits the induction coil terminals through a series capacitor.

5. The device housing a battery and charging pad as cited in claim 1 wherein a positive temperature coefficient device (PTC device) is connected in series with the induction coil, and the PTC device activates to cut-off power supplied from the induction coil to the rectifying circuit when abnormal power is supplied to the induction coil.

6. The device housing a battery and charging pad as cited in claim 1 wherein the shorting circuit is a shorting switch that short circuits the output-side of the induction coil.

7. The device housing a battery and charging pad as cited in claim 6 wherein the shorting circuit shorting switch is a semiconductor switching device.

8. The device housing a battery and charging pad as cited in claim 1 wherein the control circuit determines a charging abnormality when power transmission from the charging pad cannot be stopped even after protection circuitry in the device housing a battery has disconnected the internal battery due to over-charging.

9. The device housing a battery and charging pad as cited in claim 1 wherein the control circuit determines a charging abnormality when it detects abnormal power induced in the induction coil.

10. The device housing a battery and charging pad as cited in claim 1 wherein the control circuit determines a charging abnormality when it detects that power transmission from the charging pad cannot be stopped after internal battery charging has been stopped.

11. The device housing a battery and charging pad as cited in claim 1 wherein the device housing a battery is provided with a temperature sensor that detects the temperature of the internal battery;

and the control circuit compares the detected battery temperature with a set value and determines whether or not to start charging the internal battery.

12. The device housing a battery and charging pad as cited in claim 11 wherein the temperature of the internal battery is below the set value, the control circuit controls the shorting circuit ON when power transmission from the charging pad begins;

energy transmitted from the charging pad is not used to charge the internal battery but rather to raise the temperature of metal components surrounding the internal battery; and

when battery temperature rises to the set value, the control circuit controls the shorting circuit OFF to begin charging the internal battery.