Battery type sensing method and device for sensing battery type

1. A method of detecting a battery type, comprising:

receiving a signal of a waveform that has high and low logic levels and transitions between the high and low logic levels from a battery module in a portable computing device;

determining if the signal is in a first state which is one of the high and low logic levels for at least a first predetermined time before transitioning to a second state which is the other of the high and low logic levels;

determining if the signal transitions from the second state to the first state after a second predetermined time, and identifying the battery type in response thereto; and

asserting an indication of the battery type when a third predetermined time period after the transition from the second state to the first state has occurred.

2. The method of claim 1 , wherein the receiving the signal comprises using a one wire interface between the battery module and an embedded controller.

3. The method of claim 1 , wherein the first state comprises a logic high level.

4. The method of claim 1 , wherein the second state comprises a logic low level.

5. The method of claim 1 , wherein the first predetermined time comprises about 1 ms.

6. The method of claim 1 , wherein the second predetermined time comprises from about 1.5 ms to about 2.5 ms.

7. The method of claim 1 , wherein the third predetermined time comprises about 64 ms.

8. The method of claim 1 , wherein the identifying the battery type in response to the signal transition determination comprises identifying a first battery type if the signal has transitioned prior to a sampling at the second predetermined time.

9. The method of claim 1 , wherein the identifying the battery type in response to the signal transition determination comprises identifying a second battery type if the signal has not yet transitioned prior to a sampling at the second predetermined time.

10. The method of claim 1 , wherein the asserting the indication of the battery type comprises controlling an allowable charge rate of the battery module.

11. A method of controlling a battery module in a portable computing device, the method comprising:

receiving a signal from the battery module of a waveform that has high and low logic levels and transitions between the high and low logic levels from a battery module in a portable computing device;

determining if the signal is in a first state which is one of the high and low logic levels for at least a first predetermined time before transitioning to a second state which is the other of the high and low logic levels;

determining if the signal transitions from the second state to the first state after a second predetermined time, and identifying the battery type in response thereto;

determining a battery type using a signal received from the battery module;

allowing charging of the battery module at a first rate when a first battery type has been detected;

allowing charging of the battery module at a second rate when a second battery type has been detected; and

adjusting access to the battery module when neither the first nor the second battery types have been detected.

12. The method of claim 11 , wherein the determining the battery type comprises sampling a state of the signal at predetermined times.

13. The method of claim 11 , wherein the first rate is about half the second rate.

14. The method of claim 11 , wherein the allowing charging of the battery module at the first rate comprises disabling a portion of a charge path to the battery module.

15. The method of claim 11 , wherein the allowing charging of the battery module at the second rate comprises enabling a full charge path to the battery module.

16. The method of claim 11 , wherein the adjusting access to the battery module comprises substantially reducing charge available to be drawn from the battery module.

17. The method of claim 11 , wherein the adjusting access to the battery module comprises disabling access to charge from the battery module.

18. A portable computing device, comprising:

one or more processors; and

logic encoded in one or more non-transitory tangible media for execution by the one or more processors, and when executed operable to:

receive a signal of a waveform that has high and low logic levels and transitions between the high and low logic levels from a battery module;

determine if the signal is in a first state which is one of the high and low logic levels for at least a first predetermined time before transitioning to a second state which is the other of the high and low logic levels;

determine if the signal transitions from the second state to the first state after a second predetermined time, and identify a battery type in response thereto; and

assert an indication of the battery type when a third predetermined time period after the transition from the second state to the first state has occurred.

19. The portable computing device of claim 18 , wherein the one or more processors comprise an embedded controller.

20. The portable computing device of claim 19 , wherein the signal is received using a one wire interface between the battery module and the embedded controller.

21. The method of claim 1 , wherein the step of identifying the battery type further comprises determining a number of battery portions that are occupied in a battery module.

22. The method of claim 1 , further comprising:

in response to the asserted indication of the battery type, beginning charging of the battery module in the portable device according to the indicated battery type.

23. The portable computing device of claim 19 , further comprising logic encoded in one or more non-transitory tangible media for execution by the one or more processors, and when executed operable to:

begin charging the battery module in the portable device in response to the asserted indication of the battery type.

24. A method, comprising:

prior to allowing a battery to be charged, receiving a signal of a waveform that has high and low logic levels and transitions between the high and low logic levels from a battery module in a portable computing device;

determining if the signal is in a first state which is one of the high and low logic levels for at least a first predetermined time before transitioning to a second state which is the other of the high and low logic levels;

determining if the signal transitions from the second state to the first state after a second predetermined time, and identifying the battery type in response thereto; and

asserting an indication of the battery type when a third predetermined time period after the transition from the second state to the first state has occurred.