Electronic device with attachment and switching between batteries therefor

• US 20040036358A1
• Filed: 08/20/2002
• Published: 02/26/2004
• Est. Priority Date: 08/20/2002
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.), Sony Electronics Inc. (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Wieck, Christopher Peter
• Granted Patent: US 7,023,111 B2
• Time in Patent Office: Days
• US Class Current: 307/43
• 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: H02J 7/0063 with circuits adapted for supplying loads from the battery
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters

Abstract

A host device such as a camera, PDA, etc. can have an attachment such as a wireless modem, with both host and attachment having respective batteries. Some loads in the host are always powered by the host battery, and some loads in the attachment are always powered by the attachment battery, but some other loads in the attachment are selectively powered by either the host or attachment battery depending on a power consumption and/or the relationship between the charges remaining in the batteries.

Claims

1. An electronic system comprising:

a host device including host circuitry and at least one host battery; and

an attachment removably engaged with the host device and including an attachment battery, the attachment including at least a first circuit that is always powered by the attachment battery and at least a second circuit that is selectively powered by the host battery or the attachment battery, depending at least in part on a power consumption of at least one designated circuit associated with the attachment.

2. The system of claim 1, wherein the designated circuit is a wireless receiver circuit.

3. The system of claim 1, wherein when the power consumption of the designated circuit is above a threshold, the second circuit is powered by the host battery, otherwise the second circuit is powered by the host battery if a remaining charge capacity of the attachment battery bears a first relationship to a remaining charge capacity of the host battery, the second circuit being powered by the attachment battery if the remaining charge capacity of the attachment battery bears a second relationship to the remaining charge capacity of the host battery.

4. The system of claim 3, wherein the first and second relationships depend at least in part on at least one electrical current measurement.

5. The system of claim 4, wherein the first and second relationships depend at least in part on at least two electrical current measurements.

6. The system of claim 5, wherein the first and second relationships depend at least in part on at least three electrical current measurements.

7. The system of claim 3, wherein the first and second relationships are defined at least in part by the inequality Cc>

Hc(A+C/2)/(B+C/2), wherein Cc is the remaining charge capacity of the attachment battery, Hc is the remaining charge capacity of the host battery, A is the current in at least the first circuit, B is the current in at least one circuit that is always powered by the host battery, and C is the current in at least the second circuit.

8. The system of claim 1, wherein the host device is a personal digital assistant (PDA) and the attachment is a wireless modem.

9. The system of claim 1, wherein the host device is an imaging device and the attachment is a wireless modem.

10. A method for powering a host electronic device having an attachment, comprising:

at least during operation of the host electronic device, always powering at least a host power-only circuit using only a host battery associated with the host electronic device;

at least during operation of the attachment, always powering at least an attachment power-only circuit in the attachment using only an attachment battery associated with the attachment; and

based on at least one criterion, deciding whether to power at least one shared-power circuit associated with the attachment with the host battery or with the attachment battery.

11. The method of claim 10, wherein the criterion is at least a power consumption of at least one designated circuit associated with the attachment.

12. The method of claim 11, wherein the designated circuit is a wireless receiver circuit.

13. The method of claim 11, wherein when the power consumption of the designated circuit is above a threshold, the shared-power circuit is powered by the host battery, otherwise the shared-power circuit is powered by the host battery if a remaining charge capacity of the attachment battery bears a first relationship to a remaining charge capacity of the host battery, the shared-power circuit being powered by the attachment battery if the remaining charge capacity of the attachment battery bears a second relationship to the remaining charge capacity of the host battery.

14. The method of claim 13, wherein the first and second relationships depend at least in part on at least one electrical current measurement.

15. The method of claim 14, wherein the first and second relationships are defined at least in part by the inequality Cc>

Hc(A+C/2)/(B+C/2), wherein Cc is the remaining charge capacity of the attachment battery, Hc is the remaining charge capacity of the host battery, A is the current in at least the first circuit, B is the current in at least one circuit that is always powered by the host battery, and C is the current in at least the second circuit.

16. The method of claim 10, wherein the host electronic device is a personal digital assistant (PDA) or imaging device and the attachment is a wireless modem.

17. The method of claim 10, wherein the attachment is removably engaged with the host electronic device.

18. An electronic system comprising:

a host device including host circuitry and at least one host battery; and

an attachment removably engaged with the host device and including an attachment battery, the attachment including at least a first circuit that is always powered by the attachment battery and at least a second circuit that is selectively powered by the host battery or the attachment battery, depending at least in part at least under some conditions on a relationship between a remaining charge capacity of the attachment battery and a remaining charge capacity of the host battery.

19. The system of claim 18, wherein the relationship is used to determine which battery powers the second circuit only if a power consumption of at least one designated circuit associated with the attachment exceeds a threshold.

20. The system of claim 19, wherein the designated circuit is a wireless receiver circuit, the attachment is a wireless modem, and the host device is a PDA or imaging device.

21. A processor, comprising:

means for determining whether a power consumption of at least one designated circuit associated with an attachment to a host device exceeds a threshold;

means for determining, if the threshold is not exceeded, a relationship between a remaining charge capacity of an attachment battery associated with the attachment and a remaining charge capacity of a host battery associated with the host device; and

switching means for electrically connecting one of;

the attachment battery, and the host battery, to the second circuit, responsive to the means for determining.