Dynamic drive strength optimization

1. A flash memory device comprising:

a non-volatile storage having an array of memory blocks; and

a controller in communication with the non-volatile storage, wherein the controller is configured to:

optimize drive strength of a plurality of input/output (“I/O”) devices of the controller based on detected distortions in a VDD voltage signal supplied to the I/O devices for different drive strengths by utilizing a test pattern that comprises toggling the plurality of I/O devices for a maximum current consumption;

measure a distortion in a data signal; and

determine, iteratively, a maximum data transfer speed based on the optimized drive strength and the measured data signal distortion from the test pattern, wherein the iterative determination comprises:

provide the test pattern and at least one additional test pattern; and

re-detect distortions in the VDD voltage signal supplied to the I/O devices for different drive strengths after one of the test patterns is provided.

2. The device of claim 1 wherein the distortion in the data signal comprises a delay characterized by a slew rate and the maximum data transfer speed is determined based on the slew rate.

3. The device of claim 2 further comprising termination circuitry optimization based on the slew rate.

4. The device of claim 1 wherein to optimize the drive strength, the controller is configured to:

receive a power supply voltage at the plurality of I/O devices.

5. The device of claim 4 wherein the power supply voltage is received from a host.

6. The device of claim 1 wherein the drive strength corresponds to an output load for the plurality of I/O devices.

7. The device of claim 1 wherein to optimize the drive strength, the controller is further configured to:

compare the detected distortions with threshold distortions; and

identify the optimized drive strength as a maximum drive strength that results in the detected distortions remaining below the threshold distortions.

8. The device of claim 7 wherein the distortions comprise undershoot, overshoot, or delay.

9. The device of claim 8 wherein the undershoot comprises a voltage undershoot measurement inside the controller.

10. The device of claim 1 wherein the iterative determination comprises iteratively re-detecting distortions for different test patterns.

11. The device of claim 1 wherein the controller is configured to:

re-identify the optimized drive strength as a maximum drive strength that results in the re-detected distortions below the threshold distortions.

12. The device of claim 1 wherein at least one of the additional test patterns comprise simultaneously toggling the plurality of I/O devices for a maximum current consumption from the power supply.

13. A method for optimizing drive strength in flash memory comprising:

in a non-volatile storage device having a controller and blocks of memory, the controller:

toggling one or more input/output (“I/O”) devices of the controller using an I/O toggling mode that switches each I/O to maximize voltage level charge;

measuring a distortion in a VDD voltage signal supplied to the one or more I/O devices caused by the toggling mode;

comparing the distortion in the VDD voltage signal with an allowed distortion of the VDD voltage signal;

increasing, iteratively, the drive strength of the I/O device until the distortion is more than the allowed distortion; and

decreasing the drive strength of the I/O device when the distortion is more than the allowed distortion to generate the optimized drive strength.

14. The method of claim 13 further comprising:

storing the optimized value of drive strength in one or more of the blocks of memory, wherein the optimized value of drive strength overwrites an initial drive strength value.

15. The method of claim 13 wherein the toggling mode comprises applying a test pattern to the one or more I/O devices that results in a maximum current consumption.

16. The method of claim 13 wherein the distortion comprises undershoot, overshoot, or delay.

17. The method of claim 13 wherein the allowed distortion comprises a maximum permissible distortion threshold.

18. The method of claim 17 wherein the optimized drive strength comprises a maximum drive strength that results in the measured distortion remaining below the threshold level.

19. The method of claim 13 wherein the optimized drive strength is utilized with a configuration parameter to identify a maximum data transfer speed.

20. The method of claim 19 wherein the configuration parameter comprises at least one of a number of dies or a slew rate.

21. A memory system comprising:

a non-volatile storage having an array of memory blocks; and

a controller in communication with the blocks, the controller configured to:

receive a power supply voltage at one or more input/output (“I/O”) devices;

detect distortions in a VDD voltage signal supplied to the one or more I/O devices for different drive strengths and including when the I/O devices are each toggled for an increased voltage;

compare the detected distortions with threshold distortions; and

identify an optimized drive strength as a maximum drive strength with the detected distortions below the threshold distortions.

22. The memory system of claim 21 wherein the controller is further configured to toggle the I/O devices to maximize current consumption.

23. The memory system of claim 21 wherein the controller is further configured to:

identify a configuration parameter, wherein the configuration parameter comprises one of a slew rate or a number of dies; and

determine a maximum data transfer speed based on the optimized drive strength and the configuration parameter.