Electronic device and power supply method

• US 20050057223A1
• Filed: 08/27/2004
• Published: 03/17/2005
• Est. Priority Date: 09/16/2003
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Harada, Keiji
• Granted Patent: US 7,508,161 B2
• Time in Patent Office: Days
• US Class Current: 320/128
• CPC Class Codes: B41J 29/393 Devices for controlling or analysing the entire machine ; Controlling or analysing mechanical parameters involving printing of test patterns
• 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 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries

Abstract

An electronic device and its power supply method for charging a battery of the device, which normally operates as a master, through a power supply line, without impairing a function as a master. For example, in an environment where a battery-driven first electronic device and an AC power-driven second electronic device are interconnected via a communication path including a power supply line, it is detected whether or not the capacity of the battery in the first electronic device is sufficient, and in accordance with the result of detection, power supply from the second electronic device is requested. In accordance with the request, electric power from the AC power source of the second electronic device is supplied to the first electronic device via the power supply line, to charge the battery of the first electronic device with the power supply, and it is monitored whether or not the charging has been completed. In accordance with the result of monitoring, the power supply from the second electronic device is stopped, and the first and second electronic devices are returned to a communication stand-by status.

Claims

1. A system in which a first electronic device with at least a battery as a primary power source and a second electronic device with an AC power source as a primary power source are interconnected via a communication path including a power supply line, wherein

said first electronic device comprises:

detection means for detecting whether or not a capacity of said battery is sufficient;

request means for, in accordance with a result of detection by said detection means, issuing a request to said second electronic device, so as to receive power supply from said second electronic device;

charging means for receiving the power supply from said second electronic device via said power supply line and charging said battery;

monitor means for monitoring whether or not charging by said charging means has been completed; and

returning means for, in accordance with a result of monitoring by said monitor means, stopping the power supply from said second electronic device, and returning to a communication stand-by status for communication with said second electronic device, and

said second electronic device comprises;

power supply means for, in accordance with the request by said request means, supplying electric power from said AC power source to said first electronic device via said power supply line.

2. A power supply method for a system in which a first electronic device with at least a battery as a primary power source and a second electronic device with an AC power source as a primary power source are interconnected via a communication path including a power supply line, comprising:

a detection step of detecting whether or not a capacity of said battery in said electronic device is sufficient;

a request step of, in accordance with a result of detection at said detection step, issuing a request to said second electronic device, so as to receive power supply from said second electronic device;

a supply step of, in accordance with the request at said request step, supplying electric power from the AC power source of said second electronic device to said first electronic device via said power supply line;

a charging step of receiving the power supply from said second electronic device via said power supply line and charging said battery;

a monitor step of monitoring whether or not charging at said charging step has been completed; and

a returning step of, in accordance with a result of monitoring at said monitor step, stopping the power supply from said second electronic device, and returning said first electronic device and said second electronic device to a communication stand-by status.

3. The method according to claim 2, wherein said first and second electronic devices are in master-slave relation, and generally, said first electronic device operates as a master and said second electronic device, as a slave.

4. The method according to claim 3, further comprising:

a first switch-over step of, prior to charging at said charging step, switching said first electronic device over from a master to a slave and switching said second electronic device over from a slave to a master; and

a second switch-over step of, upon completion of charging operation at said charging step, switching said first electronic device over from the slave to the master and switching said second electronic device over from the master to the slave.

5. The method according to claim 4, further comprising:

a time monitor step of monitoring elapsed time from start of power supply from said second electronic device to said first electronic device; and

a change control step of, if it is determined by time monitoring at said time monitor step that a predetermined period has elapsed, controlling said second changing step so as to switch over master-slave relation.

6. The method according to claim 4, further comprising:

a status check step of, when the power supply from said second electronic device to said first electronic device has been started, making an inquiry about a device status from said second electronic device to said first electronic device;

a response step of, in response to said inquiry, returning a current device status from said first electronic device to said second electronic device; and

a switch-over control step of, in accordance with the content of response at said response step, controlling said second switch-over step so as to switch over master-slave relation.

7. The method according to claim 2, further comprising:

a communication step of performing data communication between said first and second electronic devices via said communication path, wherein

after completion of communication at said communication step, the capacity of said battery is detected at said detection step.

8. The method according to claim 2, wherein said first electronic device includes a cellular phone and a personal digital assistant (PDA), and

said second electronic device includes a printing apparatus for receiving data from said cellular phone and said personal digital assistant, and performing printing.

9. The method according to claim 8, wherein said printing apparatus is an inkjet printing apparatus which performs printing by using an inkjet printhead to perform printing by discharging ink.

10. The method according to claim 9, wherein said inkjet printhead has electrothermal transducers to generate thermal energy to be supplied to the ink for discharging the ink by utilizing the thermal energy.

11. An electronic device, primarily driven with a battery, connectable with an external device via a communication path including a power supply line, which normally operates as a master to said external device, comprising:

detection means for detecting whether or not a capacity of said battery is sufficient;

request means for, in accordance with a result of detection by said detection means, issuing a request to said external device, so as to receive power supply from said external device;

charging means for switching an operation status of said electronic device over from the master to a slave to said external device, receiving the power supply from said external device via said power supply line, and charging said battery;

monitor means for monitoring whether or not charging by said charging means has been completed; and

returning means for, in accordance with a result of monitoring by said monitor means, stopping the power supply from said external device, switching the operation status over from the slave to the master to said external device, and returning to a communication stand-by status for communication with said external device.

12. An electronic device, primarily driven with an AC power source, connectable to an external device via a communication path including a power supply line, which normally operates as a slave to said external device, comprising:

first switch-over means for, when electric power is supplied to said external device in accordance with a request from said external device, switching an operation status of said electronic device over from the slave to a master to said external device;

power supply means for supplying the electric power from said AC power source to said external device via said power supply line; and

second switch-over means for, when power supply to said external device is stopped, switching the operation status over from the master to the slave.

13. A power supply method for a system in which a first electronic device with at least a battery as a primary power source and a second electronic device with an AC power source as a primary power source are interconnected via a communication path including a power supply line, comprising:

a detection step of detecting whether or not a capacity of said battery in said first electronic device is sufficient;

a request step of, in accordance with a result of detection at said detection step, issuing a request to said second electronic device, so as to receive power supply from said second electronic device;

a supply step of, in accordance with the request at said request step, supplying electric power from the AC power source of said second electronic device to said first electronic device via said power supply line;

a charging step of receiving the power supply from said second electronic device via said power supply line and charging said battery;

a monitor step of monitoring whether or not charging at said charging step has been completed; and

a stop step of, in accordance with a result of monitoring at said monitor step, stopping the power supply from said second electronic device.

14. An electronic device, primarily driven with a battery, connectable with an external device via a communication path including a power supply line, which normally operates as a master to said external device, comprising:

detection means for detecting whether or not a capacity of said battery is sufficient;

request means for, in accordance with a result of detection by said detection means, issuing a request to said external device, so as to receive power supply from said external device;

charging means for changing an operation status of said electronic device from the master to a slave, and receiving the power supply from said external device via said power supply line and charging said battery;

monitor means for monitoring whether or not charging by said charging means has been completed; and

stop means for, in accordance with a result of monitoring by said monitor means, stopping the power supply from said external device.