REMAINING BATTERY CHARGE CALCULATION SYSTEM IN ELECTRONIC DEVICE

Abstract

An electronic device has a voltage converter configured to convert output voltage of a battery for supplying power for operating an electronic device into a preset voltage for output, a constant current load unit configured to receive the voltage output by the voltage converter and output a preset constant current, a battery voltage detector configured to detect the output voltage of the battery, and a remaining charge calculator configured to calculate the remaining charge of the battery based on a first battery voltage obtained by the battery voltage detector when operation of the constant current load unit is stopped and a second battery voltage obtained by the battery voltage detector when the constant current load unit is operating.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating the major components of an electronic device according to a first embodiment of the present invention;

FIG. 2 is a flow chart illustrating processing performed by the electronic device according to the first embodiment of the present invention;

FIG. 3 is a block diagram illustrating the major components of an electronic device according to a second embodiment of the present invention;

FIG. 4 is a flow chart illustrating processing performed by the electronic device according to the second embodiment of the present invention;

FIG. 5 is a block diagram illustrating the functional blocks of a digital camera a third embodiment of the present invention;

FIG. 6 is a flow chart illustrating the basic operation of the digital camera according to the third embodiment of the present invention;

FIG. 7 is a block diagram illustrating an example of the structure of the digital camera according to the third embodiment of the present invention;

FIG. 8 is a flow chart illustrating the operation of the digital camera according to the third embodiment of the present invention;

FIG. 9 is a flow chart illustrating a remaining battery charge estimation procedure according to the third embodiment of the present invention;

FIG. 10 is a block diagram illustrating an example of the structure of the electronic device according to a fourth embodiment of the present invention;

FIG. 11 is a flow chart illustrating the operation of the digital camera according to a fifth embodiment of the present invention;

FIG. 12 is a block diagram illustrating an example of the structure of a digital camera according to a sixth embodiment of the present invention;

FIG. 13 is a flow chart illustrating the operation of the digital camera according to the sixth embodiment of the present invention;

FIG. 14 is a block diagram illustrating an example of the structure of a digital camera according to a seventh embodiment of the present invention of the present invention;

FIG. 15 is a flow chart illustrating the operation of the digital camera according to a seventh embodiment of the present invention;

FIG. 16 is a block diagram showing one example of a conventional electronic device;

FIG. 17 is a flow chart illustrating processing performed by the conventional electronic device; and

FIG. 18 is a characteristics graph showing the discharge characteristics of a battery.

Claims

1. An electronic device comprising: a voltage converter configured to convert output voltage of a battery for supplying power for operating said electronic device into a preset voltage for output;a constant current load unit configured to receive the voltage output by said voltage converter and output a preset constant current;a battery voltage detector configured to detect the output voltage of said battery; anda remaining charge calculator configured to calculate a remaining charge of said battery based on a first battery voltage obtained by said battery voltage detector when operation of said constant current load unit is stopped and a second battery voltage obtained by said battery voltage detector when said constant current load unit is operating.

2. The electronic device according to claim 1, wherein said voltage converter comprises a plurality of output terminals configured to output mutually exclusive different voltages, said electronic device further comprising:a connection switching unit configured to selectively connect one of said plurality of output terminals with said constant current load unit; anda connection load control unit that controls said connection switching unit so as to switch to one of said plurality of output terminals to which said constant current load unit is to be connected based on results of a comparison of a battery voltage detected by said battery voltage detector with a predetermined voltage.

3. The electronic device according to claim 2, wherein said connection load control unit connects said constant current load unit to an output terminal that outputs the lowest voltage of said plurality of output terminals when said battery voltage is greater than a predetermined voltage.

4. The electronic device according to claim 1, wherein said voltage converter comprises a booster circuit configured to output a voltage higher than said battery voltage and a booster circuit control unit configured to switch a booster action of said booster circuit ON/OFF, said booster circuit control unit configured to switch said booster circuit ON and supply boosted output voltage to said constant current load unit when said battery voltage is lower than a predetermined voltage.

5. The electronic device according to claim 1, further comprising: a load voltage detector configured to detect an output voltage of the voltage converter connected to said constant current load unit; anda remaining battery charge correction unit configured to correct a remaining battery charge calculated by said remaining charge calculator using a voltage detected by said load voltage detector.

6. The electronic device according to claim 1, further comprising: an operating information input unit configured to input operating information for operating said electronic device; andan operation feasibility determination unit configured to determine whether or not operation according to operating information input from said operating information input unit is feasible based on a remaining battery charge calculated by said remaining charge calculator.

7. The electronic device according to claim 1, further comprising a controller configured to prohibit next calculation of said remaining battery charge by said remaining charge calculator until a predetermined period of time has elapsed after preceding calculation of said remaining battery charge by said remaining charge calculator.

8. The electronic device according to claim 7, further comprising an operating information input unit configured to input operating information for operating said electronic device, wherein said predetermined period of time is determined for each operation input from said operating information input unit.

9. The electronic device according to claim 8, wherein said predetermined period of time is variable by an arbitrary coefficient determined for each operation input from said operating information input unit.

10. The electronic device according to claim 6, wherein said remaining charge calculator calculates said remaining battery charge when a first operating instruction is input from said operating information input unit; said electronic device further comprising:a timer configured to count time to input of a second operating instruction from said operating information input unit after preceding calculation of said remaining battery charge by said remaining charge calculator; anda controller configured to prohibit calculation of said remaining battery charge by said remaining charge calculator when said second operating instruction and said first operating instruction are identical and a time counted by said timer is equal to or less than a predetermined period of time.

11. The electronic device according to claim 6, wherein said remaining charge calculator calculates said remaining battery charge when a first operating instruction is input from said operating information input unit; said electronic device further comprising:a timer configured to count time to input of a second operating instruction from said operating information input unit after preceding calculation of said remaining battery charge by said remaining charge calculator; anda controller configured to prohibit calculation of said remaining battery charge by said remaining charge calculator when power consumption for executing said second operating instruction is equal to or less than power consumption for executing said first operating instruction and the time counted by said timer is equal to or less than a predetermined period of time.

12. A remaining battery charge calculation method, comprising: a voltage conversion step of converting output voltage of a battery for supplying power for operating said remaining battery charge calculation method into a preset voltage by a voltage converter for output;a constant current load step of receiving the voltage output by said voltage converter at a constant current load unit and outputting a preset constant current at said constant current load unit;a battery voltage detection step of detecting the output voltage of said battery; anda remaining battery charge calculation step of calculating a remaining charge of said battery based on a first battery voltage obtained in said battery voltage detection step when operation of said constant current load unit is stopped and a second battery voltage obtained in said battery voltage detection step when said constant current load unit is operating.

13. The remaining battery charge calculation method according to claim 12, wherein said voltage converter comprises a plurality of output terminals configured to output mutually exclusive different voltages, said remaining battery charge calculation method further comprising:a connection switching step of selectively connecting one of said plurality of output terminals with said constant current load unit by a connection switching unit; anda connection load control step of controlling said connection switching unit so as to switch to one of said plurality of output terminals to which said constant current load unit is to be connected based on results of a comparison of a battery voltage detected in said battery voltage detection step with a predetermined voltage.

14. The remaining battery charge calculation method according to claim 13, wherein said connection load control step connects said constant current load unit to an output terminal that outputs the lowest voltage of said plurality of output terminals when said battery voltage is greater than a predetermined voltage.

15. The remaining battery charge calculation method according to claim 12, wherein said voltage converter comprises a booster circuit configured to output a voltage higher than said battery voltage, said remaining battery charge calculation method further comprising a booster circuit control step of switching a booster action of said booster circuit ON/OFF, said booster circuit control step switching said booster circuit ON and supplying boosted output voltage to said constant current load unit when said battery voltage is lower than a predetermined voltage.

16. The remaining battery charge calculation method according to claim 12, further comprising: a load voltage detection step of detecting an output voltage of the voltage converter connected to said constant current load unit; anda remaining battery charge correction step of correcting a remaining battery charge calculated in said remaining battery charge calculation step using a voltage detected in said load voltage detection step.

17. The remaining battery charge calculation method according to claim 12, further comprising: an operating information input step of inputting operating information for operating said remaining battery charge calculation method; andan operation feasibility determination step of determining whether or not operation according to operating information input in said operating information input step is feasible based on a remaining battery charge calculated in said remaining battery charge calculation step.

18. The remaining battery charge calculation method according to claim 12, further comprising a control step of prohibiting next calculation of said remaining battery charge by said remaining charge calculator until a predetermined period of time has elapsed after preceding calculation of said remaining battery charge in said remaining charge calculation step.

19. The remaining battery charge calculation method according to claim 17, wherein said remaining battery charge calculation step calculates said remaining battery charge when a first operating instruction is input in said operating information input step; said remaining battery charge calculation method further comprising:a time counting step of counting time to input of a second operating instruction in said operating information input step after preceding calculation of said remaining battery charge in said remaining battery charge calculation step;an operating instruction determination step of determining whether or not said second operating instruction and said first operating instruction are identical; anda control step of prohibiting calculation of said remaining battery charge in said remaining battery charge calculation step when said second operating instruction and said first operating instruction are identical and a time counted in said time counting step is equal to or less than a predetermined period of time.

20. The remaining battery charge calculation method according to claim 17, wherein said remaining battery charge calculation step calculates said remaining battery charge when a first operating instruction is input in said operating information input step; said remaining battery charge calculation method further comprising:a time counting step of counting time to input of a second operating instruction in said operating information input step after preceding calculation of said remaining battery charge in said remaining battery charge calculation step; anda control step of prohibiting calculation of said remaining battery charge in said remaining battery charge calculation step when power consumption for executing said second operating instruction is equal to or less than power consumption for executing said first operating instruction and the time counted in said time counting step is equal to or less than a predetermined period of time.

21. An electronic device comprising: a battery configured to supply power to an electronic device;a battery voltage detector configured to detect voltage of said battery;a current load unit configured to output current from said battery;an operating unit configured to input an operating instruction for operating said electronic device;a current setting unit configured to set a current of said current load unit based on an operating instruction input from said operating unit; anda remaining charge calculator configured to calculate a remaining battery charge based on a first battery voltage obtained by said battery voltage detector when operation of said current load unit is stopped and a second battery voltage obtained by said battery voltage detector when a current set by said current setting unit is output to said current load unit.

22. The electronic device according to claim 21, wherein said current setting unit sets current to flow said current load unit and outputs a voltage for obtaining the set current to said current load unit.

23. The electronic device according to claim 21, wherein said current setting unit further comprises a PWM controller configured to vary current to flow said current load unit by pulse duty ratio.

24. The electronic device according to claim 21, further comprising a determination unit configured to determine whether or not operation according to operating information input from said operating unit can be executed with a remaining battery charge calculated by said remaining charge calculator.

25. The electronic device according to claim 21, further comprising a coefficient recording unit configured to record coefficients set for each current value as changed by said current setting unit, wherein said remaining charge calculator outputs a coefficient of a value determined by a current output to said current load unit from said coefficient recording unit and estimates whether or not an operating instruction input from said operating unit can be executed by multiplying a result of outputting a current to said current load unit by said coefficient.

26. The electronic device according to claim 21, wherein the current setting unit varies a current output to the current load unit based on a voltage of said battery when an operating instruction is input from said operating unit and current is not output to said current load unit.

27. A control method for an electronic device, said electronic device comprising: a battery configured to supply power to an electronic device;a battery voltage detector configured to detect voltage of said battery;a current load unit configured to output current from said battery; andan operating unit configured to input an operating instruction for operating said electronic device,said control method for electronic device comprising:a current setting step of setting a current of said current load unit based on an operating instruction input from said operating unit;an acquisition step of obtaining a first battery voltage detected by said battery voltage detector when said current load unit is stopped and a second battery voltage detected by said battery voltage detector when a current set in said current setting step is output to said current load unit; anda remaining charge calculation step of calculating a remaining battery charge based on said first battery voltage and said second battery voltage obtained in said acquisition step.

28. A storage medium readable by an information processing apparatus, said storage medium storing a program which is executable by the information processing apparatus and realizes the control method described in claim 27.

29. An electronic device comprising: a power supply unit configured to convert voltage supplied from a battery into a preset voltage;a constant current load unit configured to output a predetermined constant current from said battery;a battery voltage detector configured to detect a first battery voltage when said constant current load unit is stopped and a second battery voltage when said constant current load unit is operating;an operating unit configured to input an operating instruction for operating the electronic device;a comparison unit configured to compare said first battery voltage with a preset voltage when an operating instruction is input from said operating unit; anda remaining charge calculator that calculates a remaining battery charge based on said first battery voltage and said second battery voltage detected by said battery voltage detector if results of a comparison conducted by said comparison unit indicate that said first battery voltage is at or below the preset voltage.

30. The electronic device according to claim 29, wherein said preset voltage is determined for each operating instruction input from said operating unit.

31. The electronic device according to claim 29, wherein said preset voltage can be varied by an arbitrary coefficient determined for each operating instruction input from said operating unit.

32. The electronic device according to claim 29, wherein the remaining charge calculator comprises a remaining charge calculation information recording unit configured to store reference values used in calculating whether or not there is sufficient remaining battery charge to enable operation according to an operating instruction input from said operating unit.

33. A control method for an electronic device, said electronic device comprising: a power supply unit configured to convert voltage supplied from a battery into a preset voltage;a constant current load unit configured to output a predetermined constant current from said battery;a battery voltage detector configured to detect a first battery voltage when said constant current load unit is stopped and a second battery voltage when said constant current load unit is operating; andan operating unit configured to input an operating instruction for operating the electronic device,said control method for electronic device comprising:a comparison step of comparing said first battery voltage with a preset voltage when an operating instruction is input from said operating unit; anda remaining charge calculation step of calculating a remaining battery charge based on said first battery voltage and said second battery voltage detected by said battery voltage detector if results of a comparison conducted by said comparison unit indicate that said first battery voltage is at or below the preset voltage.

34. A storage medium readable by an information processing apparatus, said storage medium storing a program which is executable by the information processing apparatus and realizes the control method described in claim 33.