Immunity against temporary and short power drops in non-volatile memory

摘要

A mechanism is presented memory circuits, such a NAND-type flash memories, to autonomously protect themselves from temporary and short power drops. A detection mechanism looks for the supply voltage to drop below a function voltage for a period of time. When such an event occurs, a suspend mechanism is activated, and after completing the last micro-operation (such as a program pulse) the memory freezes. When power is again stable at an operational level, the suspended operation is resumed. The memory controller can then be notified upon occurrence of such voltage drop by polling a special status bit. Examples of how the pausing can be implemented include altering of clock signals and suspending sub-phases of larger operations.