Regression Neural Network for Identifying Threshold Voltages to be Used in Reads of Flash Memory Devices

A flash controller including a write circuit, a read circuit configured to perform a read of a flash memory device using a threshold-voltage-shift read operation and a decoder configured to decode the results of the read, the flash controller comprising:

• a status circuit for monitoring the operation of the flash memory device to identify one or more usage characteristic values;
• a data storage configured for storing a Regression Neural Network (RNN) inference model, the regression neural network inference model configured to identify at least one threshold-voltage-shift read-error curve, each threshold-voltage-shift read-error curve identifying a number of errors as a function of threshold voltage shift offset values;
• a neural processing module coupled to the data storage, the neural processing module configured to perform a neural network operation of the stored RNN inference model to generate a threshold-voltage-shift read-error curve corresponding to the identified usage characteristic values, the input for the neural network operation including the identified one or more usage characteristic values;
• and
• a minimum function module coupled to the neural processing module, the minimum function module configured to determine a minimum value for the generated threshold-voltage-shift read-error curve and identifying a threshold voltage shift offset value corresponding to the determined minimum value;
• and
• wherein the threshold-voltage-shift read operation uses the identified threshold voltage shift offset value to perform the read.

A Solid State Drives (SSD) comprising:

• a plurality of flash memory devices;
• a flash controller that is coupled to the flash memory devices, the flash controller comprising:
• a write circuit configured to program codewords into each of the flash memory devices;
• a read circuit configured to perform reads of the flash memory devices using a threshold-voltage-shift read operation;
• a decoder coupled to the read circuit and configured to decode the results of the read;
• a status circuit for monitoring the operation of the flash memory devices to identify, for each flash memory device one or more usage characteristic value;
• a data storage configured for storing a Regression Neural Network (RNN) inference model, the RNN inference model configured to identify at least one threshold-voltage-shift read-error curve, each threshold-voltage-shift read-error curve identifying a number of errors as a function of threshold voltage shift offset values;
• a neural processing module coupled to the data storage, the neural processing module configured to perform a neural network operation of the stored RNN inference model to generate a threshold-voltage-shift read-error curve corresponding to the identified usage characteristic values, the input for the neural network operation including the identified one or more usage characteristic values;
• and
• a minimum function module coupled to the neural processing module, the minimum function module configured to determine a minimum value for the generated threshold-voltage-shift read-error curve and identifying a threshold voltage shift offset value corresponding to the determined minimum value, and
• wherein the threshold-voltage-shift read operation uses the identified threshold voltage shift offset value to perform the read.