ELECTRONIC DEVICE, AND CAPACITOR CAPACITANCE DETECTION METHOD APPLIED TO THE SAME

• US 20120161792A1
• Filed: 11/28/2011
• Published: 06/28/2012
• Est. Priority Date: 12/24/2010
• Status: Active Grant

• Current Assignee: Kioxia Corporation
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: IKEDA, Erika, Matsushita, Hiroki, Katou, Takehiko, Kawashima, Osamu
• Granted Patent: US 9,097,747 B2
• Time in Patent Office: Days
• US Class Current: 324/658
• CPC Class Codes: G01D 5/24 by varying capacitance
• CPC Class Codes: G01R 27/26 Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
• CPC Class Codes: G01R 27/2605 Measuring capacitance capacitive sensors G01D5/24
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive sensing
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/00302 Overcharge protection
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices

Abstract

According to one embodiment, an electronic device includes a capacitor, a power supply device, a discharger and a capacitance detector. The capacitor is used as a backup power supply. The power supply device charges the capacitor. The discharger discharges the capacitor. The capacitance detector maintains a terminal voltage of the capacitor at a given level for a predetermined time, by controlling an operating time of the power supply device. The capacitance detector allows the discharger to start the discharge the predetermined time later. The capacitance detector detects a capacitance of the capacitor based on a transient response characteristic of the discharge.

Claims

1. An electronic device comprising:

a capacitor configured for use as a backup power supply;

a power supply configured to charge the capacitor;

a discharger configured to discharge the capacitor; and

a capacitance detector configured to

maintain a terminal voltage of the capacitor for a first time, by controlling an operating time of the power supply,

allow the discharger to start the discharge after the first time elapses, and

detect a capacitance of the capacitor based on a transient response characteristic of the discharge.

2. The electronic device of claim 1, wherein the capacitance detector comprises a discharge controller configured to detect, as a time during which the terminal voltage is maintained, the first time from a time when the terminal voltage reaches a second voltage or higher, the second voltage being lower than a first voltage associated with the power supply.

3. The electronic device of claim 2, wherein the discharge controller is further configured to stop the discharge effected by the discharger when the terminal voltage reaches a third voltage or lower, the third voltage being lower than the second voltage.

4. The electronic device of claim 3, wherein the capacitance detector further comprises a capacitance calculator configured to calculate the capacitance of the capacitor based on a time from beginning to end of the discharge.

5. The electronic device of claim 4, further comprising an intermittent charge controller configured to intermittently charge the capacitor,

wherein the discharge controller is further configured to inhibit operation of the intermittent charge controller at least during the first time.

6. The electronic device of claim 5, wherein the intermittent charge controller is further configured to stop intermittent charge control by detecting that the terminal voltage has reached a first threshold voltage or higher and to start the intermediate charge control by detecting that the terminal voltage has reached a second threshold voltage or lower, the second threshold voltage being lower than the first threshold voltage.

7. The electronic device of claim 6, further comprising:

a first voltage detector configured to detect that the terminal voltage is the second voltage or higher; and

a second voltage detector configured to detect that the terminal voltage is the third voltage or lower,

wherein the discharge controller is further configured to detect that an elapsed time from a time when the first voltage detector detects that the terminal voltage is the second voltage or higher reaches the first time or more, and to stop the discharge when the second voltage detector detects that the terminal voltage is the third voltage or lower.

8. The electronic device of claim 7, wherein:

the second threshold voltage is equal to the third voltage;

the intermittent charge controller comprises a Schmitt trigger configured to detect that the terminal voltage is the third voltage or lower; and

the Schmitt trigger comprises the second voltage detector.

9. The electronic device of claim 6, wherein the first threshold voltage is equal to the first voltage.

10. A method for detecting a capacitance of a capacitor configured for use as a backup power supply in an electronic device comprising the capacitor, a power supply configured to charge the capacitor, and a discharger configured to discharge the capacitor, wherein the method comprises:

maintaining a terminal voltage of the capacitor for a first time by controlling an operating time of the power supply;

allowing the discharger to start the discharge after the first time elapses; and

detecting a capacitance of the capacitor based on a transient response characteristic of the discharge.

11. The method of claim 10, further comprising detecting, as a time during which the terminal voltage is maintained, the first time from a time when the terminal voltage reaches a second voltage or higher, the second voltage being lower than a first voltage associated with the power supply.

12. The method of claim 11, further comprising stopping the discharge effected by the discharger when the terminal voltage reaches a third voltage or lower, the third voltage being lower than the second voltage.

13. The method of claim 12, wherein detecting the capacitance of the capacitor comprises calculating the capacitance of the capacitor based on a time from beginning to end of the discharge.

14. The method of claim 13, wherein:

the electronic device further comprises an intermittent charge controller configured to intermittently charge the capacitor; and

the method further comprises inhibiting operation of the intermittent charge controller at least during the first time.

15. The method of claim 14, further comprising:

stopping intermittent charge control by detecting that the terminal voltage has reached a first threshold voltage or higher; and

starting the intermediate charge control by detecting that the terminal voltage has reached a second threshold voltage or lower, the second threshold voltage being lower than the first threshold voltage.

16. The method of claim 15, further comprising:

detecting that the terminal voltage is the second voltage or higher;

detecting that the terminal voltage is the third voltage or lower;

detecting that an elapsed time from a time when the terminal voltage is detected to be equal to or higher than the second voltage reaches the first time or more; and

stopping the discharge when a state where the terminal voltage is detected to be the third voltage or lower.

17. The method of claim 16, wherein:

the second threshold voltage is equal to the third voltage;

the intermittent charge controller comprises a Schmitt trigger; and

the terminal voltage is detected by the Schmitt trigger as the third voltage or lower.

18. The method of claim 15, wherein the first threshold voltage is equal to the first voltage.