Background Auto-refresh Apparatus and Method for Non-Volatile Memory Array

An apparatus for automatically refreshing a non-volatile memory array in the background without memory interruption, comprising:

• a set of output bitlines coupled to the memory array;
• a dead-time detection circuit for detecting when no memory access requests are pending;
• a temporary storage circuit coupled to the memory array and to the set of output bitlines for temporarily storing data from a selected group of rows in the memory array;
• a circuit responsive to a memory refresh signal request including a selection circuit for selecting a selected group of rows in the memory array;
• a circuit responsive to the dead-time circuit for reading data from the selected group of rows and writing the data into the temporary storage circuit in the memory array;
• a circuit for re-mapping addresses of the data from the selected group of rows during refresh to addresses in the temporary storage circuit containing the data and for re-mapping addresses of the data after refresh from the selected group of rows back to addresses in the memory array;
• and
• a circuit for erasing and re-programming the selected group of rows of the memory array.