Methods and apparatus for a power supply control circuit
Various embodiments of the present technology comprise a method and apparatus for a power supply control circuit. In various embodiments, the apparatus is adapted to control the power supplied by a battery to a heating element. The apparatus may comprise a memory for storing known data and circuitry configured to control the delivery of power from the battery to the heating element according to measured parameters, calculated parameters, and the known data.
1. An apparatus adapted to power a heating element, comprising:
a battery;
a control circuit connected to the battery and configured to:
store known battery data comprising a first profile and a second profile;
determine a capacity of the battery according to the first profile;
determine a resistance of the battery according to the second profile;
calculate a first power value based on the determined resistance;
generate a control signal according to the calculated first power value; and
selectively connect the battery to the heating element according to the control signal.
2. The apparatus of claim 1 , wherein determining the resistance of the battery comprises:
measuring an actual voltage of the battery;
utilizing the first profile to determine a capacity of the battery according to the measured actual voltage; and
utilizing the second profile to determine the resistance of the battery according to the determined capacity.
3. The apparatus of claim 1 , wherein the control circuit is configured to calculate the first power further based on a first resistance value of the heating element at a start time.
4. The apparatus of claim 3 , wherein the known battery data stored by the control circuit further comprises a third profile comprising a relationship between resistance values of the heating element and time.
5. The apparatus of claim 4 , further comprising a timer to measure an elapsed operation time, wherein the elapsed operation time is measured from the start time.
6. The apparatus of claim 5 , wherein, when the timer reaches a predetermined elapsed operation time, the control circuit is configured to calculate a new first power according to:
a second resistance value of the heating element; and
the third profile.
7. The apparatus of claim 1 , further comprising a switch positioned between the battery and the heating element, wherein the switch is responsive to the control signal and electrically connects the battery to the heating element.
8. The apparatus of claim 1 , wherein:
the first profile comprises a relationship between battery voltage values and battery capacity values; and
the second profile comprises a relationship between battery resistance values and the battery capacity values.
9. The apparatus of claim 1 , wherein the control signal is defined as a ratio of a predetermined target power to the calculated first power.
10. An apparatus adapted to power a heating element with a battery, comprising:
a control circuit configured to:
measure an actual voltage of the battery;
determine a capacity of the battery according to the measured actual voltage and a first battery profile;
determine a resistance of the battery according to the determined capacity and a second battery profile;
calculate a first power using the measured actual voltage, the determined resistance of the battery, and a resistance of the heating element;
calculate a ratio of a predetermined target power and the calculated first power; and
electrically connect the battery to the heating element according to the calculated ratio.
11. The apparatus of claim 10 , wherein: the first battery profile comprises a relationship between voltage values and capacity values; and the second battery profile comprises a relationship between resistance values of the battery and the capacity values.
12. The apparatus of claim 10 , wherein the control circuit is further configured to:
measure an elapsed operation time; and
determine an aged resistance value of the heating element, comprising utilizing known heating element data and the elapsed operation time value.
13. The apparatus of claim 10 , wherein the control circuit comprises a switch positioned between the battery and the heating element, wherein the switch electrically connects the battery to the heating element according to the calculated ratio.
14. A system, comprising:
a battery configured to power to a heating element;
a memory configured to store known battery data comprising a first profile and a second profile; and
a control circuit configured to:
determine an actual capacity of the battery according to a measured actual voltage of the battery and the first profile;
determine a resistance of the battery according to the second profile;
compute a first power using the measured actual voltage, the determined resistance of the battery, and a resistance of the heating element;
generate a control signal based on the computed first power and a predetermined target power; and
selectively connect the battery to the heating element according to the control signal.
15. The system of claim 14 , wherein:
the first profile comprising a relationship between battery voltage values and battery capacity values; and
the second profile comprising a relationship between battery resistance values and the battery capacity values.
16. The system of claim 14 , wherein determining the resistance of the battery comprises comparing the determined actual capacity of the battery with the second profile.
17. The system of claim 14 , wherein the memory is further configured to store a third profile comprising a relationship between resistance values of the heating element and time.
18. The system of claim 14 , wherein the control signal is a ratio of the predetermined target power to the calculated first power.
19. The system of claim 14 , further comprising a timer to measure an elapsed operation time; wherein, when the timer reaches a predetermined elapsed operation time, the control circuit is further configured to calculate a new first power according to:
a second resistance value of the heating element; and
a third profile comprising a relationship between resistance values of the heating element and time.