Parallel charging

1. An apparatus for parallel charging, the apparatus comprising:

a charging system comprising:

a first charger comprising a first current path configured to propagate a first current;

a second charger comprising a second current path configured to propagate a second current;

a node combining the first current path and the second current path;

a combined current path from the node to a power storage unit;

a charging controller coupled to the first current path;

a first indication path coupled between the first current path and the charging controller, the first indication path configured to indicate the first current separately from the second current; and

a second indication path coupled between the second current path and the charging controller, the second indication path configured to indicate the second current separately from the first current.

2. The apparatus of claim 1 , wherein:

the first charger comprises a buck converter; and

the second charger comprises a charge pump.

3. The apparatus of claim 1 , wherein the charging system comprises:

an indication signal combiner that is coupled:

between the first indication path and the charging controller; and

between the second indication path and the charging controller.

4. The apparatus of claim 3 , wherein the indication signal combiner is configured to:

accept a first indication signal of the first current flowing through the first current path;

accept a second indication signal of the second current flowing through the second current path;

combine the first indication signal of the first current flowing through the first current path and the second indication signal of the second current flowing through the second current path to produce a combined indication signal; and

provide the combined indication signal to the charging controller.

5. The apparatus of claim 4 , wherein:

the combined indication signal is responsive to a first magnitude of the first current flowing through the first current path and a second magnitude of the second current flowing through the second current path; and

the charging controller is configured to control at least one switching parameter of the first charger based on the combined indication signal.

6. The apparatus of claim 4 , wherein:

the charging system comprises:

a third charger comprising a third current path configured to propagate a third current,

the third current path coupled to the node; and

a third indication path coupled between the third current path and the indication signal combiner, the third indication path configured to indicate the third current separately from the first current and the second current using a third indication signal; and

the indication signal combiner is configured to:

accept the third indication signal of the third current flowing through the third current path; and

combine the first indication signal of the first current flowing through the first current path, the second indication signal of the second current flowing through the second current path, and the third indication signal of the third current flowing through the third current path to produce the combined indication signal.

7. The apparatus of claim 1 , wherein the charging controller is:

separate from the first charger and separate from the second charger; or

integrated with the first charger and separate from the second charger.

8. The apparatus of claim 1 , wherein the charging controller is configured to control operation of at least the first charger based on the first current flowing through the first current path and the second current flowing through the second current path.

9. The apparatus of claim 1 , wherein:

the second charger comprises a second current sensor, the second current sensor coupled between the second current path and the second indication path.

10. The apparatus of claim 9 , wherein:

the second current sensor is configured to provide, to the charging controller via the second indication path, a second indication signal indicative of the second current flowing through the second current path; and

the charging controller is configured to control a combined current of the charging system based on the second indication signal.

11. The apparatus of claim 10 , wherein:

the second current comprises at least one of a second input current or a second charging current; and

the combined current comprises at least one of a combined input current or a combined charging current.

12. The apparatus of claim 10 , further comprising:

the power storage unit; and

a power source adapter,

wherein the second current path comprises at least one of:

a second input-current path coupled to the power source adapter; or

a second charging-current path coupled to the power storage unit.

13. The apparatus of claim 10 , wherein:

the first charger comprises a first current sensor, the first current sensor coupled between the first current path and the first indication path.

14. The apparatus of claim 13 , wherein:

the first current sensor is configured to provide, to the charging controller via the first indication path, a first indication signal indicative of the first current flowing through the first current path; and

the charging controller is configured to control the combined current of the charging system based on the first indication signal and the second indication signal.

15. The apparatus of claim 14 , wherein the charging system comprises:

an indication signal combiner coupled to the first indication path and the second indication path, the indication signal combiner configured to:

combine at least the first indication signal and the second indication signal to produce a combined indication signal; and

provide the combined indication signal to the charging controller.

16. The apparatus of claim 1 , further comprising:

a first printed circuit board comprising the first charger; and

a second printed circuit board comprising the second charger.

17. The apparatus of claim 1 ,

wherein the charging system is configured to charge the power storage unit.

18. The apparatus of claim 17 , further comprising:

a display screen coupled to the power storage unit; and

a processor coupled to the power storage unit, the processor operatively coupled to the display screen and configured to present one or more graphical images on the display screen,

wherein the power storage unit is configured to provide power to the display screen and the processor.

19. The apparatus of claim 1 , wherein:

the first charger comprises a first current sensor, the first current sensor coupled between the first current path and the first indication path;

the second charger comprises a second current sensor, the second current sensor coupled between the second current path and the second indication path;

the first current sensor is configured to provide, to the charging controller via the first indication path, a first indication signal comprising a scaled version of the first current; and

the second current sensor is configured to provide, to the charging controller via the second indication path, a second indication signal comprising a scaled version of the second current.

20. An apparatus for charging at least one power storage unit, the apparatus comprising:

a first charger comprising means for propagating a first current at least partially through the first charger;

a second charger comprising means for propagating a second current at least partially through the second charger;

means for combining the means for propagating the first current and the means for propagating the second current;

a combined current path from the means for combining to the at least one power storage unit;

first means for indicating the first current separately from the second current;

second means for indicating the second current separately from the first current;

means for generating a combined indication signal responsive to the first means for indicating and the second means for indicating; and

means for controlling a charging of the at least one power storage unit based on the combined indication signal.

21. The apparatus of claim 20 , wherein the means for controlling comprises at least one of:

means for regulating at least one charging current to provide constant-current charging;

means for regulating at least one input current to protect at least one power source adapter; or

means for regulating a voltage corresponding to the at least one power storage unit.

22. The apparatus of claim 20 , wherein the second means for indicating the second current comprises:

means for sensing the second current in the second charger to produce a second indication signal; and

means for propagating the second indication signal to the means for generating.

23. A method for operating a charging system, the method comprising:

sensing a first current flowing through a first current path of a first charger separately from a second current to produce a first indication signal;

sensing the second current flowing through a second current path of a second charger separately from the first current to produce a second indication signal;

propagating the first indication signal along a first indication path separately from the second indication signal;

propagating the second indication signal along a second indication path separately from the first indication signal;

combining the first indication signal and the second indication signal to produce a combined indication signal; and

controlling the charging system based on the combined indication signal.

24. The method of claim 23 , wherein the controlling comprises:

adjusting a combined current based on the combined indication signal, the combined current corresponding to at least the first current and the second current.

25. The method of claim 24 , wherein the adjusting comprises at least one of:

adjusting the first current to maintain the combined current substantially within a target range for the combined current; or

adjusting the first current to counteract a change to the second current.

26. The method of claim 23 , further comprising:

propagating the first current of the first charger to a node; and

propagating the second current from the second charger to the node.

27. The method of claim 23 , wherein the controlling comprises:

adjusting at least one switching parameter of the first charger based on the combined indication signal.

28. An apparatus for parallel charging, the apparatus comprising:

a charging system comprising:

a buck charger comprising

a first current path, the first current path coupled to a charging voltage node and configured to propagate a first current;

a charge pump charger comprising

a second current path, the second current path coupled to the charging voltage node and configured to propagate a second current;

a node combining the first current path and the second current path;

a combined current path from the node to a power storage unit;

a charging controller coupled to the first current path;

a first indication path coupled between the charging controller and the first current path, the first indication path configured to provide a first indication signal of the first current separately from the second current; and

a second indication path coupled between the charging controller and the second current path, the second indication path configured to provide a second indication signal of the second current separately from the first current.

29. The apparatus of claim 28 , wherein:

the charge pump charger comprises a current sensor, the current sensor coupled between the second current path configured to propagate the second current and the second indication path.

30. The apparatus of claim 28 , wherein at least one of:

the first current path comprises a first input-current path, and the second current path comprises a second input-current path; or

the first current path comprises a first charging-current path, and the second current path comprises a second charging-current path.