Data storage device adjusting a power loss threshold based on samples of supply voltage
A data storage device is disclosed comprising a non-volatile memory. A supply voltage for powering the non-volatile memory is sampled to generate supply voltage samples. A power loss threshold is adjusted based on the supply voltage samples, and a power loss event is detected based on the power loss threshold and the supply voltage, wherein an emergency operation is executed when the power loss event is detected.
1. A data storage device comprising:
a non-volatile memory; and
control circuitry configured to:
receive a supply voltage for powering the non-volatile memory;
sample the supply voltage to generate supply voltage samples;
adjust a power loss threshold based on the supply voltage samples;
detect a power loss event based on the power loss threshold and the supply voltage; and
execute an emergency operation when the power loss event is detected.
2. The data storage device as recited in claim 1 , wherein the control circuitry is further configured to execute the emergency operation when the supply voltage falls below the power loss threshold in an analog domain.
3. The data storage device as recited in claim 1 , wherein the control circuitry is further configured to execute the emergency operation when at least one of the supply voltage samples is less than the power loss threshold in a digital domain.
4. The data storage device as recited in claim 3 , wherein the control circuitry is further configured to execute the emergency operation when at least two consecutive supply voltage samples is less than the power loss threshold.
5. The data storage device as recited in claim 1 , wherein the control circuitry is further configured to adjust the power loss threshold based on an average of the supply voltage samples.
6. The data storage device as recited in claim 1 , wherein the control circuitry is further configured to adjust the power loss threshold based on a standard deviation of the supply voltage samples.
7. The data storage device as recited in claim 1 , wherein the control circuitry is further configured to adjust the power loss threshold by subtracting a standard deviation of the supply voltage samples from an average of the supply voltage samples.
8. The data storage device as recited in claim 1 , wherein the control circuitry is further configured to adjust the power loss threshold in quantized steps.
9. The data storage device as recited in claim 8 , wherein the quantized step comprises at least ten millivolts.
10. The data storage device as recited in claim 1 , further comprising a head actuated over a disk.
11. The data storage device as recited in claim 10 , wherein the control circuitry is further configured to position the head near an outer diameter of the disk based on the power loss threshold.
12. The data storage device as recited in claim 1 , wherein the non-volatile memory comprises a semiconductor memory.
13. A method of operating a data storage device, the method comprising:
receiving a supply voltage for powering a non-volatile memory;
sampling the supply voltage to generate supply voltage samples;
adjusting a power loss threshold based on the supply voltage samples;
detecting a power loss event based on the power loss threshold and the supply voltage; and
executing an emergency operation when the power loss event is detected.
14. The method as recited in claim 13 , further comprising executing the emergency operation when the supply voltage falls below the power loss threshold in an analog domain.
15. The method as recited in claim 13 , further comprising executing the emergency operation when at least one of the supply voltage samples is less than the power loss threshold in a digital domain.
16. The method as recited in claim 13 , further comprising executing the emergency operation when at least two consecutive supply voltage samples is less than the power loss threshold.
17. The method as recited in claim 13 , further comprising adjusting the power loss threshold based on an average of the supply voltage samples.
18. The method as recited in claim 13 , further comprising adjusting the power loss threshold based on a standard deviation of the supply voltage samples.
19. The method as recited in claim 13 , further comprising adjusting the power loss threshold by subtracting a standard deviation of the supply voltage samples from an average of the supply voltage samples.
20. The method as recited in claim 13 , further comprising adjusting the power loss threshold in quantized steps.
21. The method as recited in claim 20 , wherein the quantized step comprises at least ten millivolts.
22. The method as recited in claim 13 , further comprising a head actuated over a disk.
23. The method as recited in claim 22 , further comprising positioning the head near an outer diameter of the disk based on the power loss threshold.
24. The method as recited in claim 13 , wherein the non-volatile memory comprises a semiconductor memory.