System and method for low battery detection

1. A method of monitoring battery status, wherein the battery is connected to a voltage pump which drives a variable load, comprising:

determining a start of a monitoring period to monitor the operation of the voltage pump;

monitoring operation of the voltage pump during the monitoring period by sampling a control signal multiple times during the monitoring period, wherein the control signal indicates whether the voltage pump is on;

if at least a pre-determined number of samples indicate that the voltage pump was on during each of the pre-determined number of samples, then determining that the voltage pump is operating at a pre-determined level; and

when the voltage pump is operating at the pre-determined level, then analyzing at least one previously determined level of operation of the voltage pump for a previous monitoring period to determine the battery status.

2. The method of claim 1 , wherein the monitoring period corresponds to a period of heavy consistent load.

3. The method of claim 2 , wherein the period of heavy consistent load corresponds to the transmission of at least a portion of a message preamble in a wireless network.

4. The method of claim 3 wherein determining a start of a monitoring period comprises identifying the portion of the message preamble that corresponds to an approximately constant current at the variable load.

5. The method of claim 1 , wherein the control signal indicates that an oscillator within the voltage pump is enabled.

6. The method of claim 1 , wherein analyzing at least one previously determined level of operation of the voltage pump for a previous monitoring period to determine the status of the battery comprises:

if the voltage pump was operating at the pre-determined level for a pre-determined number of previous monitoring periods, then determining that the battery status is low.

7. The method of claim 1 , wherein the predetermined number of samples indicating that the voltage pump was on is equal to all the samples taken during the monitoring period.

8. A method of monitoring battery status, wherein the battery is connected to a voltage pump which drives a variable load, comprising:

monitoring operation of the voltage pump during a monitoring period by sampling a control signal multiple times during the monitoring period, wherein the control signal indicates whether the voltage pump is on;

processing the samples to determine if at least a pre-determined number of the samples taken during the monitoring period indicates that the voltage pump was on during each of the pre-determined number of samples to determine if the voltage pump is operating at a pre-determined level;

when the voltage pump is operating at the pre-determined level, then adjusting a value representing the battery status; and

if the value representing the battery status is at least equal to a pre-determined threshold, then determining that a low battery status exists.

9. The method of claim 8 , further comprising:

if the samples indicate that the voltage pump was not on for at least the pre-determined number of samples, then adjusting the value representing the battery status in a manner opposite that used when the voltage pump is operating at the pre-determined level.

10. The method of claim 8 , further comprising:

if the low battery status exists, then providing a notification indicating the low battery status.

11. The method of claim 8 , wherein the monitoring period corresponds to a period of heavy consistent load.

12. The method of claim 11 , wherein the period of heavy consistent load corresponds to the transmission of at least a portion of a message preamble in a wireless network.

13. The method of claim 8 , wherein the control signal indicates that an oscillator within the voltage pump is enabled.

14. A battery monitoring system, comprising:

a battery connected to a voltage pump;

the voltage pump, which drives a variable load, wherein the voltage pump is switched on and off via a control signal; and

a processor programmed to:

monitor operation of the voltage pump by sampling the control signal multiple times during a monitoring period;

if at least a pre-determined number of the samples taken during the monitoring period indicates that the voltage pump was on during each of the pre-determined number of samples, then determine that the voltage pump is operating at a pre-determined level; and

when the voltage pump is operating at the pre-determined level, then analyzing at least one previously determined level of operation of the voltage pump for a previous monitoring period to determine the battery status.

15. The system of claim 14 , wherein the voltage pump and the processor are integrated into a single device.

16. The system of claim 14 , wherein the monitoring period corresponds to a period of heavy consistent load.

17. The system of claim 16 , wherein the period of heavy consistent load corresponds to the transmission of at least a portion of a message preamble in a wireless network.

18. The system of claim 14 , wherein the control signal indicates that an oscillator within the voltage pump is enabled.

19. The system of claim 14 , wherein analyzing at least one previously determined level of operation of the voltage pump for a previous monitoring period to determine the status of the battery comprises:

if the voltage pump was operating at the pre-determined level for a pre-determined number of previous monitoring periods, then determining that the battery status is low.

20. The system of claim 14 , further comprising a transmitter for transmitting the battery status.