Apparatuses and methods for over-temperature protection of energy storage devices

1. A charging system, comprising:

a temperature sensor thermally coupled with an energy storage device and configured for generating a temperature signal responsive to a temperature of the energy storage device;

a circuit temperature sensor on a semiconductor device configured for generating a circuit temperature signal responsive to a temperature of the semiconductor device;

a charge adjuster operably coupled to the temperature sensor and the circuit temperature sensor, the charge adjuster configured to:

determine when the temperature signal or the circuit temperature signal indicates an over-temperature condition;

decrement a down counter based on the determination; and

generate a desired current signal based on a value of the down counter;

a comparator configured for comparing a current level signal to the desired current signal to generate a charge adjustment signal, the current level signal indicating a level of charge current being supplied to the energy storage device; and

a charge controller on the semiconductor device and configured for generating and adjusting a current of a charging signal for charging the energy storage device responsive to the charge adjustment signal.

2. The charging system of claim 1 , wherein the charge controller comprises a pulse-width modulation controller on the semiconductor device and is configured for generating and adjusting a pulse-width of a charging signal for charging the energy storage device responsive to the charge adjustment signal.

3. The charging system of claim 1 , further comprising a timer configured for providing a predefined time delay between when the temperature signal exceeds a throttle threshold and the decrementing of the down counter.

4. The charging system of claim 3 , wherein the timer is further configured for providing the predefined time delay between when the circuit temperature signal exceeds a circuit throttle threshold and the decrementing of the down counter.

5. The charging system of claim 1 , wherein the charge adjuster further comprises:

a temperature monitor configured for generating a reduction signal when the temperature signal is above a throttle threshold;

a circuit temperature monitor configured for generating a circuit reduction signal when the circuit temperature signal is above a circuit throttle threshold;

and

a digital-to-analog converter configured for converting the value of the down counter to the desired current signal;

wherein the charge adjuster is further configured to decrement the down counter in response to the reduction signal, the circuit reduction signal, or a combination thereof.

6. The charging system of claim 5 , further comprising a timer configured for providing a predefined time delay between generation of the reduction signal and the decrementing of the down counter.

7. The charging system of claim 5 , further comprising a stop-charge module configured for:

disabling the charge controller from generating the charging signal when the temperature signal is above a maximum temperature; and

enabling the charge controller to generate the charging signal when the temperature signal is below a reset temperature.

8. The charging system of claim 7 , wherein the stop-charge module is further configured for resetting the down counter to a predetermined starting count value as part of the enabling.

9. The charging system of claim 1 , further comprising a differential amplifier configured for:

measuring the level of charge current delivered to the energy storage device; and

outputting the current level signal to the comparator.

10. A charging system, comprising:

a temperature sensor thermally coupled with an energy storage device and for generating a temperature signal responsive to a temperature of the energy storage device;

a charge adjuster coupled to the temperature sensor, the charge adjuster configured to:

determine using a temperature monitor when the temperature signal is above a throttle threshold;

generate a reduction signal when the temperature signal is above a throttle threshold;

decrement a down counter when the reduction signal is detected; and

convert, using a digital-to-analog converter, a value of the down counter to a desired current signal;

a comparator for comparing a current level signal to the desired current signal to generate a pulse-width adjustment signal, the current level signal indicating a level of charge current supplied to the energy storage device; and

a pulse-width-modulation controller for generating and adjusting a pulse-width of a charging signal for charging the energy storage device responsive to the pulse-width adjustment signal.

11. The charging system of claim 10 , further comprising a timer for providing a predefined time delay between determining when the temperature signal is above the throttle threshold and decrementing of the down counter.

12. The charging system of claim 10 , further comprising:

a circuit temperature sensor on a semiconductor device including the pulse-width-modulation controller, the circuit temperature sensor for generating a circuit temperature signal responsive to a temperature of the semiconductor device; and

wherein the charge adjuster is further configured to:

determine using a circuit temperature monitor when the circuit temperature signal is above a circuit throttle threshold;

generate a circuit reduction signal when the circuit temperature signal is above a circuit throttle threshold; and

decrement the down counter when the circuit reduction signal is detected.

13. The charging system of claim 12 , further comprising a timer for providing a predefined time delay between determining when the circuit temperature signal is above the circuit throttle threshold and the decrementing of the down counter.

14. The charging system of claim 10 , further comprising a stop-charge module for:

disabling the pulse-width-modulation controller from generating the charging signal when the temperature signal is above a maximum temperature; and

re-enabling the pulse-width-modulation controller to generate the charging signal when the temperature signal is below a reset temperature.

15. The charging system of claim 14 , wherein the stop-charge module is further configured for resetting the down counter to a predetermined starting count value as part of the enabling.

16. A method of charging an energy storage device, comprising:

sensing a temperature of the energy storage device to generate a temperature signal with a temperature sensor thermally coupled with the energy storage device;

asserting, by a temperature monitor included in a charge adjuster, a reduction signal when the temperature signal is above a throttle threshold;

decrementing, by the charge adjuster, a down counter responsive to the reduction signal;

generating, by the charge adjuster, a desired current signal based on a value of the down counter;

comparing a current level signal to the desired current signal to generate a charge adjustment signal, the current level signal indicating a level of charge current supplied to the energy storage device; and

generating a charging signal to charge the energy storage device with a current responsive to the charge adjustment signal.

17. The method of claim 16 , further comprising providing a predefined time delay between an assertion of the reduction signal and the decrementing of the down counter.

18. The method of claim 16 , further comprising:

sensing a circuit temperature of a semiconductor device including a pulse-width-modulation controller;

asserting a circuit reduction signal when the circuit temperature is above a circuit throttle threshold;

decrementing the down counter responsive to the circuit reduction signal; and

generating the charging signal is performed by the pulse-width-modulation controller.

19. The method of claim 18 , further comprising providing a predefined time delay between an assertion of the circuit reduction signal and the decrementing of the down counter.

20. The method of claim 16 , further comprising:

disabling the generating of the charging signal with variable pulse widths when the temperature signal is above a maximum temperature; and

re-enabling the generating of the charging signal with variable pulse widths when the temperature signal is below a reset temperature.

21. The method of claim 20 , further comprising resetting the down counter to a predetermined starting count value as part of the enabling.