Power management systems and methods for a mobile device

1. A power management system for a mobile device, comprising:

a primary power management circuit configured to receive an input voltage and use the input voltage to supply power to the mobile device;

a secondary power management circuit configured to select at least one of a battery signal from a rechargeable battery, a first power source input, or a second power source input as the input voltage to the primary power management circuit, the input voltage to the primary power management circuit being received by the primary power management circuit from the secondary power management circuit;

the primary power management circuit being further configured to use the first power source to charge the rechargeable battery; and

the secondary power management circuit being further configured to use the second power source input to charge the rechargeable battery.

2. The power management system of claim 1 , wherein the second power source input is received from a universal serial bus (USB) source and the first power source input is received from a non-USB source.

3. The power management system of claim 1 , wherein if the battery signal is below an operational threshold of the mobile device, then the secondary power management circuit being operable to select the first power source input or the second power source input as the input voltage to the primary power management circuit.

4. The power management system of claim 3 , wherein if the battery input is above the operational threshold of the mobile device, then the secondary power management circuit being operable to select the battery signal as the input voltage to the primary power management circuit.

5. The power management system of claim 2 , wherein the mobile device is configured to receive enumeration information and set a maximum current of the second power source based on the enumeration information.

6. The power management system of claim 1 , wherein if the mobile device is connected to both the first power source input and the second power source input, then the primary and secondary power management circuits being operable to set a charge rate for the rechargeable battery using both the first and second power source inputs.

7. The power management system of claim 6 , wherein the primary and secondary power management circuits receive one or more control inputs from a processing device in the mobile device to set the charge rate between the first and second power source inputs.

8. The power management system of claim 1 , further comprising:

a switching device coupled between the first power source input and the rechargeable battery, wherein the first power management circuit controls a current flow through the switching device in order to charge the rechargeable battery from the first power source input.

9. A mobile device, comprising:

a rechargeable battery;

a processing sub-system;

a primary power management circuit configured to receive an input voltage and use the input voltage to supply power to the mobile processing device;

a secondary power management circuit configured to select at least one of a battery signal from the rechargeable battery, a first power source input, or a second power source input as the input voltage to the primary power management circuit, the input voltage to the primary power management circuit being received by the primary power management circuit from the secondary power management circuit;

the primary power management circuit being further configured to use the first power source to charge the rechargeable battery; and

the secondary power management circuit being further configured to use the second power source to charge the rechargeable battery.

10. The mobile device of claim 9 , wherein the second power source input is received from a universal serial bus (USB) source and the first power source input is received from a non-USB source.

11. The mobile device of claim 9 , wherein the primary power management circuit is a DA9030 power management integrated circuit.

12. The mobile device of claim 9 , wherein the primary power management circuit is a PM6650 power management integrated circuit.

13. The mobile device of claim 9 , wherein the secondary power management circuit is a BQ24032 single-chip charge and system power-path management integrated circuit.

14. A method for supplying power to a mobile device that includes a primary power management circuit, a secondary power management circuit and a rechargeable battery, comprising:

selecting at least one of a battery input from the rechargeable battery, a first power source input, or a second power source input as an input voltage to the primary power management circuit;

using the input voltage to the primary power management circuit to supply power to the mobile device, the input voltage to the primary power management circuit being received by the primary power management circuit from the secondary power management circuit; and

using at least one of the first power source input and the second power source input to charge the rechargeable battery;

wherein the primary power management circuit is used to charge the rechargeable battery from the first power source input and the secondary power management circuit is used to charge the rechargeable battery from the second power source input.

15. The method of claim 14 , wherein the second power source input is received from a universal serial bus (USB) source and the first power source input is received from a non-USB source.

16. The method of claim 14 , wherein the secondary power management circuit is used to select at least one of the battery input from the rechargeable battery, the first power source input, or the second power source input as the input voltage to the primary power management circuit.

17. The method of claim 14 , further comprising:

detecting if the battery signal from the rechargeable battery is below an operational threshold of the mobile device;

if the battery input from the rechargeable battery is below the operational threshold of the mobile device, then selecting at least one of the first power source input or the second power source input as the input voltage to the primary power management circuit; and

if the battery signal from the rechargeable battery is not below the operational threshold of the mobile device, then selecting the battery input as the input voltage to the primary power management circuit.

18. The method of claim 14 , further comprising:

receiving enumeration information from a universal serial bus (USB) host device; and

setting a maximum current of the second power source based on the enumeration information.

19. The method of claim 14 , further comprising:

if the mobile device is connected to both the first power source input and the second power source input, then setting a charge rate for the rechargeable battery using both the first and second power source inputs.