Methods and apparatus for charging a battery in a peripheral device

• US 20060061927A1
• Filed: 11/10/2005
• Published: 03/23/2006
• Est. Priority Date: 10/22/2001
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Computer Incorporated (Apple Inc.)
• Inventors: Fadell, Anthony M., Krah, Christoph
• Granted Patent: US 7,656,623 B2
• Time in Patent Office: Days
• US Class Current: 361/90
• CPC Class Codes: G06F 1/266 Arrangements to supply power to external peripherals either directly from the computer or under computer control, e.g. supply of power through the communication port, computer controlled power-strips
• CPC Class Codes: G06F 1/325 Power saving in peripheral device
• CPC Class Codes: H02J 1/001 Hot plugging or unplugging of load or power modules to or from power distribution networks
• CPC Class Codes: H02J 1/06 Two-wire systems
• CPC Class Codes: H02J 2207/30 Charge provided using DC bus or data bus of a computer
• CPC Class Codes: H02J 7/00302 Overcharge protection
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence

Abstract

A power manager for managing power delivered to a battery operated peripheral device is disclosed. The power manager includes an input current limiter arranged to suppress a power surge associated with an insertion event by a power cable arranged to provide an external voltage. A voltage converter unit coupled to the input current limiter converts the received external voltage to a supply voltage that is transmitted by way of a main bus to a voltage sensor unit coupled thereto. During the insertion event, a comparator unit coupled to the voltage sensor, sends a first switching signal to a switchover circuit that responds by connecting the peripheral device and an uncharged battery to the main bus such that the supply voltage is provided thereto. When the battery is substantially fully charged, the switchover circuit responds by electrically disconnecting the battery so as to not overcharge the battery.

Claims

1. A power manager unit for managing power delivered to a battery powered device, comprising:

a voltage converter unit arranged to convert an external voltage to a supply voltage;

a voltage sensor unit coupled to the voltage converter unit for sensing a voltage associated with a charged state of the battery;

a comparator unit coupled to the voltage sensor unit arranged to generate a switching signal based upon the sensed voltage, wherein a first switching signal corresponds to a not fully charged battery and wherein a second switching signal corresponds to a fully charged battery; and

a switchover circuit coupled to the comparator unit that responds to the second switching signal by electrically disconnecting the battery so as to not overcharge the battery, and wherein the switchover circuit responds to the first switching signal by connecting the battery powered device and a not fully charged battery to the voltage converter unit such that the supply voltage is provided thereto.

2. A power manager as recited in claim 1, wherein the external voltage is delivered by way of a cable that includes a number of lines at least one of which is a power line arranged to carry the external voltage from the external voltage supply to the battery powered device.

3. A power management unit as recited in claim 2, further comprising:

an input current limiter arranged to suppress a power surge resulting from a power line insertion event when the power line is carrying the external voltage.

4. A power management unit as recited in claim 2, wherein during a power line removal event, the comparator unit sends a third signal to the switchover circuit that responds by concurrently disconnecting a main bus from the power line and connecting the battery to the battery powered device, thereby providing a substantially uninterrupted supply voltage to the battery powered device.

5. A power management unit as recited in claim 2, wherein the cable is a I.E.E.E. 1394 compliant cable.

6. A method of managing power delivered to a battery powered device, comprising:

converting an external voltage to a supply voltage;

sensing a voltage associated with a charged state of the battery;

generating a switching signal based upon the sensed voltage, wherein a first switching signal corresponds to a not fully charged battery and wherein a second switching signal corresponds to a fully charged battery;

disconnecting the battery so as to not overcharge the battery in response to the second switching signal; and

connecting the battery powered device and the not fully charged battery to the voltage converter unit such that the supply voltage is provided thereto in response to the first switching signal.

7. A method as recited in claim 6, wherein the external voltage is delivered by way of a cable that includes a number of lines at least one of which is a power line arranged to carry the external voltage from the external voltage supply to the battery powered device.

8. A method as recited in claim 7, further comprising:

suppressing a power surge associated with a power line insertion event.

9. A method for managing power as recited in claim 8, further comprising:

generating a third signal in response to a power line removal event; and

disconnecting a main bus from the battery powered device and connecting the battery to the battery powered device in response to the third signal.

10. A method as recited in claim 7, wherein the cable is a I.E.E.E. 1394 compliant cable.

11. A computer program product for managing power delivered to a battery powered device, comprising:

computer code for converting an external voltage to a supply voltage;

computer code for sensing a voltage associated with a charged state of the battery;

computer code for generating a switching signal based upon the sensed voltage, wherein a first switching signal corresponds to a not fully charged battery and wherein a second switching signal corresponds to a fully charged battery;

computer code for disconnecting the battery so as to not overcharge the battery in response to the second switching signal;

computer code for connecting the battery powered device and the not fully charged battery to the voltage converter unit such that the supply voltage is provided thereto in response to the first switching signal; and

computer readable medium for storing the computer code.

12. A computer program product as recited in claim 11, wherein the external voltage is delivered by way of a cable that includes a number of lines at least one of which is a power line arranged to carry the external voltage from the external voltage supply to the battery powered device.

13. A computer program product as recited in claim 12, further comprising:

computer code for suppressing a power surge associated with a power line insertion event.

14. A computer program product for managing power as recited in claim 12, further comprising:

computer code for generating a third signal in response to a power line removal event; and

computer code for disconnecting a main bus from the battery powered device and connecting the battery to the battery powered device in response to the third signal.

15. A computer program product as recited in claim 11, wherein the cable is a I.E.E.E. 1394 compliant cable.

16. A power manager for managing power delivered to a battery powered device, comprising:

a voltage converter unit arranged to convert an external voltage to a supply voltage;

a voltage sensor unit coupled to the voltage converter unit for sensing a voltage associated with a charged state of the battery;

means for generating a switching signal based upon the sensed voltage, wherein a first switching signal corresponds to a not fully charged battery and wherein a second switching signal corresponds to a fully charged battery;

means for disconnecting the battery so as to not overcharge the battery in response to the second switching signal; and

means for connecting the battery powered device and the not fully charged battery to the voltage converter unit such that the supply voltage is provided thereto in response to the first switching signal.

17. A power manager as recited in claim 16, wherein the battery powered device is a portable media player.