Method of controlling a charging voltage for extending the lifetime of a secondary power source and a storage device performing the same

1 . A method of controlling a charging voltage, the method comprising:

determining, a characteristic of at least one capacitor included in a secondary power source;

in response to the at least one capacitor having a predetermined characteristic, charging the secondary power source with a charging voltage generated by performing a predetermined control scheme in which a voltage level of the charging voltage is adjusted based on a present capacitance of the secondary power source and environmental information value received from an environmental sensor,

wherein charging the secondary power source by performing the predetermined control scheme includes:

receiving a first environmental information value from the environmental sensor;

setting the voltage level of the charging voltage to a first voltage level in response to the first environmental information value;

charging the secondary power source including at least one capacitor with the charging voltage having the first voltage level;

receiving a second environmental information value from the environmental sensor;

in response to the second environmental information value being different than the first environmental information value, selectively changing the voltage level of the charging voltage; and

charging the secondary power source with the charging voltage having the selectively changed voltage level,

wherein selectively changing the voltage level of the charging voltage includes determining whether the secondary power source satisfies a predetermined energy condition corresponding to the second environmental information value by:

obtaining the present capacitance of the secondary power source; and

obtaining an expected change energy value based on the present capacitance of the secondary power source and a second voltage level different from the first voltage level;

in response to the second environmental information value being different than the first environmental information value, and in response to the secondary power source satisfying the predetermined energy condition, changing the voltage level of the charging voltage to the second voltage level; and

in response to the second environmental information value being different than the first environmental information value, and in response to the secondary power source not satisfying the predetermined energy condition, maintaining the voltage level of the charging voltage at the first voltage level,

wherein the second voltage level corresponds to the second environmental information value,

wherein the present capacitance of the secondary power source is determined by a monitoring circuit, and

wherein charging the secondary power source with the charging voltage having the selectively changed voltage level includes:

in response to the second environmental information value being different than the first environmental information value, and in response to the secondary power source satisfying the predetermined energy condition, charging the secondary power source with the charging voltage having the second voltage level; and

in response to the second environmental information value being different than the first environmental information value, and in response to the secondary power source not satisfying the predetermined energy condition, charging the secondary power source with the charging voltage having the first voltage level.

2 . The method of claim 1 , wherein the determining whether the secondary power source satisfies the predetermined energy condition includes:

comparing a predetermined energy value with the expected change energy value.

3 . The method of claim 2 , wherein:

in response to the predetermined energy value being less than the expected change energy value, it is determined that the predetermined energy condition is satisfied, and

in response to the predetermined energy value being greater than or equal to the expected change energy value, it is determined that the predetermined energy condition is unsatisfied.

4 . The method of claim 1 , wherein the selectively changing the voltage level of the charging voltage further includes:

after the voltage level of the charging voltage is changed to the second voltage level, storing the second environmental information value.

5 . The method of claim 1 , wherein the environmental sensor includes a temperature sensor, a humidity sensor, a pressure sensor, a motion sensor, a temporal sensor, a spatial sensor, an illumination sensor, an acceleration sensor, a vibration sensor, a mechanical stress sensor or a shock sensor.

6 . The method of claim 1 , further comprising:

after the secondary power source is charged based on the charging voltage having the first voltage level, storing the first environmental information value.

7 . The method of claim 1 , wherein operations of receiving the second environmental information value, selectively changing the voltage level of the charging voltage, and charging the secondary power source with the charging voltage having the selectively changed voltage level are periodically performed.

8 . The method of claim 1 , wherein operations of receiving the second environmental information value, selectively changing the voltage level of the charging voltage, and charging the secondary power source with the charging voltage having the selectively changed voltage level are performed in response to an external command.

9 . The method of claim 1 , further comprising:

in response to the second environmental information value being equal to the first environmental information value, maintaining the voltage level of the charging voltage; and

charging the secondary power source with the charging voltage having the maintained voltage level.

10 . A method of controlling a charging voltage, the method comprising:

determining, a characteristic of at least one capacitor included in a secondary power source;

in response to the at least one capacitor having a first characteristic, charging the secondary power source with the charging voltage generated by performing a first control scheme in which a voltage level of the charging voltage is adjusted based on a present capacitance of the secondary power source; and

in response to the at least one capacitor having a second characteristic, charging the secondary power source with the charging voltage generated by performing a second control scheme in which the voltage level of the charging voltage is adjusted based on the present capacitance of the secondary power source and environmental information value received from an environmental sensor,

wherein charging the secondary power source by performing the second control scheme includes:

receiving a first environmental information value from the environmental sensor;

setting the voltage level of the charging voltage to a first voltage level in response to the first environmental information value;

charging the secondary power source with the charging voltage having the first voltage level;

receiving a second environmental information value from the environmental sensor;

in response to the second environmental information value being different than the first environmental information value, selectively changing the voltage level of the charging voltage; and

charging the secondary power source with the charging voltage having the selectively changed voltage level,

wherein selectively changing the voltage level of the charging voltage includes:

determining whether the secondary power source satisfies a predetermined energy condition corresponding to the second environmental information value by:

obtaining the present capacitance of the secondary power source; and

obtaining an expected change energy value based on the present capacitance of the secondary power source and a second voltage level different from the first voltage level;

in response to the second environmental information value being different than the first environmental information value, and in response to the secondary power source satisfying the predetermined energy condition, changing the voltage level of the charging voltage to the second voltage level; and

in response to the second environmental information value being different than the first environmental information value, and in response to the secondary power source not satisfying the predetermined energy condition, maintaining the voltage level of the charging voltage at the first voltage level,

wherein the second voltage level corresponds to the second environmental information value,

wherein the present capacitance of the secondary power source is determined by a monitoring circuit, and

wherein charging the secondary power source with the charging voltage having the selectively changed voltage level includes:

in response to the second environmental information value being different than the first environmental information value, and in response to the secondary power source satisfying the predetermined energy condition, charging the secondary power source with the charging voltage having the second voltage level; and

in response to the second environmental information value being different than the first environmental information value, and in response to the secondary power source not satisfying the predetermined energy condition, charging the secondary power source with the charging voltage having the first voltage level.

11 . The method of claim 10 , wherein:

the first characteristic represents that a remaining lifetime of the at least one capacitor decreases rapidly as the voltage level of the charging voltage increases, and

the second characteristic represents that the remaining lifetime of the at least one capacitor decreases slowly as the voltage level of the charging voltage increases, or the remaining lifetime of the at least one capacitor is irrelevant to the voltage level of the charging voltage.

12 . The method of claim 10 , wherein the charging the secondary power source by performing the first control scheme includes:

setting the voltage level of the charging voltage to a third voltage level;

charging the secondary power source based on the charging voltage having the third voltage level;

obtaining the present capacitance of the secondary power source by performing a monitoring operation;

in response to the present capacitance of the secondary power source being less than a first reference capacitance, changing the voltage level of the charging voltage to a second fourth voltage level different from the third voltage level; and

charging the secondary power source based on the charging voltage having the second fourth voltage level.

13 . The method of claim 12 , wherein the fourth voltage level is higher than the third voltage level.

14 . The method of claim 12 , wherein charging the secondary power source by performing the first control scheme further includes:

in response to the present capacitance of the secondary power source being greater than or equal to the first reference capacitance, maintaining the voltage level of the charging voltage at the third voltage level.

15 . The method of claim 12 , wherein the charging of the secondary power source by performing the first control scheme further includes:

after the secondary power source is charged based on the charging voltage having the fourth voltage level, obtaining the present capacitance of the secondary power source by performing the monitoring operation;

in response to the present capacitance of the secondary power source being less than a second reference capacitance, changing the voltage level of the charging voltage to a fifth voltage level, the second reference capacitance being different from the first reference capacitance, the fifth voltage level being different from the third voltage level and the fourth voltage level; and

charging the secondary power source based on the charging voltage having the fifth voltage level.

16 . The method of claim 15 , wherein:

the fifth voltage level is higher than the third voltage level and the fourth voltage level, and

the second reference capacitance is less than the first reference capacitance.

17 . A method of controlling a charging voltage that is used to charge a secondary power source including at least one capacitor, the method comprising:

determining whether the at least one capacitor has a first characteristic or a second characteristic different from the first characteristic;

in response to the at least one capacitor having the first characteristic, charging the secondary power source by performing a first control scheme in which a voltage level of the charging voltage is adjusted based on a present capacitance of the secondary power source; and

in response to the at least one capacitor having the second characteristic, charging the secondary power source by performing a second control scheme in which the voltage level of the charging voltage is adjusted based on the present capacitance of the secondary power source and environmental information value received from an environmental sensor,

wherein the first characteristic represents that a remaining lifetime of the at least one capacitor decreases rapidly as the voltage level of the charging voltage increases,

wherein the second characteristic represents that the remaining lifetime of the at least one capacitor decreases slowly as the voltage level of the charging voltage increases, or the remaining lifetime of the at least one capacitor is irrelevant to the voltage level of the charging voltage,

wherein charging the secondary power source by performing the first control scheme includes:

setting the voltage level of the charging voltage to a first voltage level;

charging the secondary power source based on the charging voltage having the first voltage level;

obtaining the present capacitance of the secondary power source;

in response to the present capacitance of the secondary power source being less than a first reference capacitance, changing the voltage level of the charging voltage to a second voltage level higher than the first voltage level; and

charging the secondary power source based on the charging voltage having the second voltage level, and

wherein charging the secondary power source by performing the second control scheme includes:

receiving initial environmental information value from the environmental sensor;

setting the voltage level of the charging voltage to a third voltage level based on the initial environmental information value;

charging the secondary power source based on the charging voltage having the third voltage level;

storing the initial environmental information value as previous environmental information value;

receiving present environmental information value from the environmental sensor;

in response to the present environmental information value being different than the previous environmental information value, selectively changing the voltage level of the charging voltage;

charging the secondary power source based on the charging voltage having the selectively changed voltage level; and

storing the present environmental information value as new previous environmental information value,

wherein selectively changing the voltage level of the charging voltage includes:

determining whether the secondary power source satisfies a predetermined energy condition corresponding to the present environmental information value by:

obtaining the present capacitance of the secondary power source; and

obtaining an expected change energy value based on the present capacitance of the secondary power source and a fourth voltage level different from the third voltage level;

in response to the present environmental information value being different than the previous environmental information value, and in response to the secondary power source satisfying the predetermined energy condition, changing the voltage level of the charging voltage to the fourth voltage level; and

in response to the present environmental information value being different than the previous environmental information value, and in response to the secondary power source not satisfying the predetermined energy condition, maintaining the voltage level of the charging voltage at the third voltage level,

wherein the fourth voltage level corresponds to the present environmental information value,

wherein the present capacitance of the secondary power source is determined by a monitoring circuit, and

wherein charging the secondary power source with the charging voltage having the selectively changed voltage level includes:

in response to the present environmental information value being different than the previous environmental information value, and in response to the secondary power source satisfying the predetermined energy condition, charging the secondary power source with the charging voltage having the fourth voltage level; and

in response to the present environmental information value being different than the previous environmental information value, and in response to the secondary power source not satisfying the predetermined energy condition, charging the secondary power source with the charging voltage having the third voltage level.