Power source circuit, electronic device being equipped with same power source circuit and control method of power source circuit

• US 20030052645A1
• Filed: 09/17/2002
• Published: 03/20/2003
• Est. Priority Date: 09/18/2001
• Status: Active Grant

• Current Assignee: Envision AESC Energy Devices Ltd.
• Original Assignee: NEC Tokin Corporation (Yageo Corporation)
• Inventors: Sasaki, Hiroshi
• Granted Patent: US 7,019,416 B2
• Time in Patent Office: Days
• US Class Current: 320/110
• CPC Class Codes: H02J 7/0063 with circuits adapted for supplying loads from the battery
• CPC Class Codes: H02J 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices

Abstract

A power source circuit is provided which is capable of improving an efficiency of using energy of a chemical battery cell and of responding suitably to an intermittent change in a load current. Since, during a load burst period in an odd-numbered order, a load is driven by power accumulated in a first power storing section and, during a load burst period in an even-numbered order, a load is driven by power accumulated in a second power storing section, even if a duty ratio of the load burst period in one period during which the load burst period occurs intermittently exceeds fifty percent, energy required during the load burst period is fed from the first or the second power storing section and the chemical battery cell does not discharge during the load burst period. Therefore, an amount of a voltage having dropped due to an internal impedance of a power supplying section becomes small and, as a result, when the power source circuit is applied to the electronic device which becomes inoperable due to a temporary voltage drop in the power source, an operational life of the power supplying section is made longer.

Claims

1. A power source circuit for supplying power to a load in which load burst periods intermittently occurs during each of which a load current increases and decreases in a burst manner comprising:

a power supplying section to generate an electromotive force and to feed it to said load;

a plurality of power storing sections to be charged by said electromotive force fed from said power supplying section and to accumulate power; and

a control section to select, for every said load burst period, an arbitrary one of said power storing sections that have been already charged and to feed only power that has been accumulated in the selected power storing section during said load burst period to said load and to charge a power storing section that has not yet been charged.

2. A power source circuit for supplying power to a load in which load burst periods intermittently occurs during each of which a load current increases and decreases in a burst manner comprising:

a power supplying section to generate an electromotive force and to feed it to said load;

a first power storing section to be charged by an electromotive force fed from said power supplying section and to accumulate power;

a second power storing section to be charged by an electromotive force fed from said power supplying section and to accumulate power; and

a control section to feed only power accumulated in said first power storing section during a load burst period in an odd-numbered order out of said load burst periods to said load and to feed only power accumulated in said second power storing section during a load burst period in an even-numbered order out of said load burst periods.

3. The power source circuit according to claim 2, wherein said control section comprises:

a load state monitoring circuit to monitor a load current flowing through said load and to output, based on a result from the monitoring, a signal representing information about occurrence of a load burst period showing production of said load burst period;

a power storing section monitoring circuit to monitor a voltage of said first power storing section and a voltage of said second power storing section and to output, based on a result from the monitoring, a signal representing information about charging and discharging showing a state of charging and discharging in said first power storing section and said second power storing section; and

a power supply controlling circuit to input said information about occurrence of a load burst period and said information about a state of charging and discharging and, to feed, during said load burst period in said odd-numbered order out of said load burst periods, only power accumulated in said first power storing section that has been already charged to said load and to charge said second power storing section that has not been charged and to feed, during said load burst period in said even-numbered order out of said load burst periods, only power accumulated in said second power storing section that has been charged to said load and to charge said first power storing section that has not been charged.

4. The power source circuit according to claim 2, wherein each of said first and second power storing sections has at least capacity capable of feeding required power to said load during one load burst period.

5. The power source circuit according to claim 2, wherein said power supplying section is made up of a chemical battery cell or a direct current power source whose maximum output current is limited to a specified current value and wherein each of said first and second power storing sections is made up of an electric double-layer capacitor or a secondary battery cell.

6. The power source circuit according to claim 2, wherein said control section comprises:

a load state monitoring means to monitor a load current flowing through said load and to output, based on a result from the monitoring, a signal representing information about occurrence of a load burst period showing production of said load burst period;

a power storing section monitoring means to monitor a voltage of said first power storing section and a voltage of said second power storing section and to output, based on a result from the monitoring, a signal representing information about charging and discharging showing a state of charging and discharging in said first power storing section and said second power storing section; and

a power supply controlling means to input said information about occurrence of a load burst period and said information about a state of charging and discharging and, to feed, during said load burst period in said odd-numbered order out of said load burst periods, only power accumulated in said first power storing section that has been already charged to said load and to charge said second power storing section that has not been charged and to feed, during said load burst period in said even-numbered order out of said load burst periods, only power accumulated in said second power storing section that has been charged to said load and to charge said first power storing section that has not been charged.

7. A method for controlling a power source circuit for supplying power to a load in which load burst periods intermittently occurs during each of which a load current increases and decreases in a burst manner, said method comprising:

a step of placing a power supplying section to generate an electromotive force and to feed it to a load, a first power storing section to be charged by an electromotive force generated by said power supplying section, and to accumulate power and to feed the accumulated power to said load, and a second power storing section to be charged by an electromotive force generated by said power supplying section, and to accumulate power and to feed the accumulated power to said load; and

a step of feeding, when a load burst period during which a load current flowing through said load increases intermittently occurs, only power accumulated in said first power storing section to said load during a load burst period in an odd-numbered order out of said load burst periods and only power accumulated in said second power storing section to said load during a load burst period in an even-numbered order out of said load burst periods.

8. A method for controlling a power source circuit for supplying power to a load in which load burst periods intermittently occurs during each of which a load current increases and decreases in a burst manner, said method comprising:

a process of placing a power supplying section to generate an electromotive force and to accumulate power and to feed it to a load, a first power storing section to be charged by an electromotive force fed from said power supplying section, to accumulate power and to feed the accumulated power supplied by said power supplying section to said load, and a second power storing section to be charged by an electromotive force supplied by said power supplying section and to accumulate power, and to feed the accumulated power to said load;

a process of monitoring a load state to monitor a load current flowing through said load and to output, based on a result from the monitoring, a signal representing information about occurrence of said load burst period showing production of said load burst period;

a process of monitoring a power storing section to monitor a voltage of said first power storing section and a voltage of said second power storing section and to output, based on a result from the monitoring, a signal representing information about charging and discharging showing a state of charging and discharging in said first power storing section and said second power storing section;

a first process of supplying power to input said information about occurrence of said load burst period and information about a state of charging and discharging and to feed, during a load burst period in an odd-numbered order out of said load burst periods, only power accumulated in said first power storing section that has been already charged to said load and to charge said second power storing section that has not been charged; and

a second process of supplying power to feed, during a load burst period in an even-numbered order out of said load burst periods, only power accumulated in said second power storing section that has been charged to said load and to charge said first power storing section that has not been charged.

9. An electronic device being equipped with a power source circuit for supplying power to a load in which load burst periods intermittently occurs during each of which a load current increases and decreases in a burst manner, said power source circuit comprising:

a power supplying section to generate an electromotive force and to feed it to said load;

a plurality of power storing sections to be charged by said electromotive force fed from said power supplying section and to accumulate power; and

a control section to select, for every said load burst period, an arbitrary one of said power storing sections that have been already charged and to feed only power that has been accumulated in the selected power storing section during said load burst period to said load and to charge a power storing section that has not yet been charged.

10. The electronic device according to claim 9, relating to a portable cellular phone.

11. The electronic device according to claim 9, relating to a digital still camera.

12. An electronic device being equipped with a power source circuit for supplying power to a load in which load burst periods intermittently occurs during each of which a load current increases and decreases in a burst manner, said power source circuit comprising:

a power supplying section to generate an electromotive force and to feed it to said load;

a first power storing sections to be charged by an electromotive force fed from said power supplying section and to accumulate power;

a second power storing sections to be charged by an electromotive force fed from said power supplying section and to accumulate power; and

a control section to feed only power accumulated in said first power storing section during a load burst period in an odd-numbered order out of said load burst periods to said load and to feed only power accumulated in said second power storing section during a load burst period in an even-numbered order out of said load burst periods.

13. The electronic device according to claim 12, relating to a portable cellular phone.

14. The electronic device according to claim 12, relating to a digital still camera.