US Patent 10573397 Parameter tracking for non-volatile memory to avoid over-programming

On a non-volatile memory circuit, peripheral circuitry generates programming voltages based on parameter values. If parameter values are incorrectly translated into programming voltages, data may be over-programmed, resulting in high bit error rates (BERs). The memory system can monitor the error rates using memory cell voltage distributions for different portions of the memory and look for signatures of such incorrect implementation. For example, by monitoring the BER along word lines that are most prone to error due to incorrectly implemented programming parameters, the memory system can determine if the programming parameters for the corresponding portion of a memory device indicate such anomalous behavior. If such a signature is found, the memory system checks to see whether the programming parameters should be adjusted, such as by comparing the programming parameters used on one die to programming parameters used on another die of the memory system, and adjust the programming parameters accordingly.