Battery charger

• US 8,441,230 B2
• Filed: 11/18/2010
• Issued: 05/14/2013
• Est. Priority Date: 09/08/2008
• Status: Active Grant

• Current Assignee: Techtronic Power Tools Technology Limited (Techtronic Industries Company Limited)
• Original Assignee: Techtronic Power Tools Technology Limited (Techtronic Industries Company Limited)
• Inventors: Boyles, Samuel, Rajani, Umesh, Tocco, Anthony Thomas, Hornick, Mike, Miller, William Stuart
• Primary Examiner(s): Berhanu, Samuel
• Application Number:
  US12/949,484
• Publication Number:
  US 20110121783A1
• Time in Patent Office: 908 Days
• Field of Search: 320/106, 320/107, 320/112, 320/114
• US Class Current: 320/107
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0042 characterised by the mechanical construction
• CPC Class Codes: H02J 7/0045 concerning the insertion or the connection of the batteries
• CPC Class Codes: H02J 7/00714 in response to battery charging or discharging current
• CPC Class Codes: H02J 7/007182 in response to battery voltage

Abstract

An energy-efficient and compact battery charger. The battery charger includes, among other things, a charging port, a power supply module, a battery charger control module or controller, a power control safety module, a battery charger switch, and an indicator. The controller, the power control safety module, and the battery charger switch work in conjunction with each other to control the operation of the battery charger. The controller is configured to execute a charging control process which detects the insertion of a battery pack into the charging port, controls the charging of the battery pack, and controls the illumination or display of the indicator. The power control safety module includes a power control safety circuit that is configured to prevent the charging current and/or the charging voltage from damaging the battery charger or battery pack during a malfunction.

Claims

1. A battery charger comprising:

a housing including a charging port configured to receive a battery pack;

a power supply module electrically connected to a power source and configured to supply power to the battery charger,

wherein the battery charger is configured to operate in a normal operational power mode and a low operational power mode;

a controller configured to

determine whether the charging port is to receive a first charging current,

determine whether the charging port is to receive a second charging current, wherein the first charging current is greater than the second charging current,

operate the battery charger in the normal operational power mode when the charging port is to receive the first charging current or the second charging current, and

detect the presence of the battery pack in the charging port; and

a protection circuit including a first semiconductor switch configured to allow the first charging current or the second charging current to be supplied to the charging port when the protection circuit is receiving a charging signal from the controller, and a second semiconductor switch configured to prevent the charging current from being supplied to the charging port when the protection circuit is not receiving the charging signal from the controller.

2. The battery charger of claim 1, wherein the second charging current is a trickle charging current.

3. The battery charger of claim 1, wherein the charging current flows through the first semiconductor switch.

4. The battery charger of claim 1, wherein the protection circuit further includes a fuse.

5. The battery charger of claim 4, wherein the second semiconductor switch causes the fuse to open when the charging current is being supplied to the charging port and the protection circuit is not receiving the charging signal from the controller.

6. A battery charger comprising:

a housing including a charging port configured to receive a battery pack;

a power supply module electrically connected to a power source and configured to supply power to the battery charger;

a controller configured to

during a normal operational power mode,

generate a charging signal to enable the charging port to receive a charging current; and

during a low operational power mode,

remove power from each of the plurality of terminals; and

a protection circuit configured to receive the charging signal from the controller when the protection circuit is in the normal operational power mode, the protection circuit including a first semiconductor switch and a second semiconductor switch,

wherein the first semiconductor switch allows the charging current to be supplied to the charging port when the protection circuit is receiving the charging signal from the controller, and wherein the second semiconductor switch prevents the charging current from being supplied to the charging port when the protection circuit is not receiving the charging signal from the controller.

7. The battery charger of claim 6, wherein the protection circuit further includes a fuse.

8. The battery charger of claim 7, wherein the second semiconductor switch causes the fuse to open when the charging current is being supplied to the charging port and the protection circuit is not receiving the charging signal from the controller.

9. The battery charger of claim 6, wherein the charging current flows through the first semiconductor switch.

10. The battery charger of claim 6, further comprising a battery pack detection device positioned within the charging port and electrically connected to the controller.

11. The battery charger of claim 10, wherein the battery pack detection device includes a first conductive part coupled to a negative terminal of the power supply module and a second conductive part coupled to the controller.

12. The battery charger of claim 11, wherein the first conductive part and the second conductive part are separated from one another by a distance.

13. The battery charger of claim 12, wherein the distance between the first conductive part and the second conductive part is spanned when the battery pack is inserted into the charging port.

14. A battery charger comprising:

a housing including a charging port configured to receive a battery pack;

a power supply module electrically connected to a power source and configured to supply power to the battery charger;

a controller configured to

determine whether the charging port is to receive a first charging current,

determine whether the charging port is to receive a second charging current, and

receive an indication of a presence of the battery pack in the charging port and generate a charging signal to enable the charging port to receive the first charging current or the second charging current;

a protection circuit including a first semiconductor switch configured to allow the first charging current or the second charging current to be supplied to the charging port when the protection circuit is receiving the charging signal from the controller, and a second semiconductor switch configured to prevent the charging current from being supplied to the charging port when the protection circuit is not receiving the charging signal from the controller; and

a battery pack detection device positioned within the charging port and electrically connected to the controller, the battery pack detection device including a

a first conductive part coupled to a negative terminal of the power supply module, and

a second conductive part coupled to the controller,

wherein the first conductive part and the second conductive part are separated from one another by a distance, and

wherein the distance between the first conductive part and the second conductive part is spanned by a terminal of the battery pack when the battery pack is inserted into the charging port.

15. The battery charger of claim 14, wherein the battery pack detection device provides the indication of the presence of the battery pack in the charging port to the controller.

16. The battery charger of claim 14, further comprising an evaluation unit that determines an impedance of the battery pack and evaluates the status of the battery pack based on the impedance.

17. The battery charger of claim 14, wherein a voltage of the first conductive part is a battery charger reference voltage and a voltage of the second conductive part is the battery charger control voltage.

18. The battery charger of claim 17, wherein the voltage of the second conductive part is reduced from the battery charger control voltage to the battery charger reference voltage when the battery pack is inserted into the charging port.