A non-volatile memory device capable of reading and writing a large number
of memory cells with multiple read/write circuits in parallel has
features to reduce power consumption during read, and program/verify
operations. A read or program verify operation includes one or more
sensing cycles relative to one or more demarcation threshold voltages to
determine a memory state. In one aspect, selective memory cells among the
group being sensed in parallel have their conduction currents turned off
when they are determined to be in a state not relevant to the current
sensing cycle. In another aspect, a power-consuming period is minimized
by preemptively starting any operations that would prolong the period. In
a program/verify operation cells not to be programmed have their bit
lines charged up in the program phase. Power is saved when a set of these
bit lines avoids re-charging at every passing of a program phase.