Memory device, operating method of memory device, and memory system

A method of operating a memory device, the method comprising:

• performing an nth program loop including a program voltage apply operation and a verify operation on a selected memory cell among a plurality of memory cells;
• storing a verify result according to the verify operation of the nth program loop in a first latch of a page buffer connected to the selected memory cell through a bit line;
• and
• performing an (n+1)th program loop while applying, to the bit line, a bit line voltage determined based on a verify result according to a verify operation of an (n−1)th program loop, which is pre-stored in a second latch of the page buffer, and the verify result according to the verify operation of the nth program loop, which is stored in the first latch.

A memory system comprising:

• a memory device including a plurality of memory cells, the memory device including a plurality of page buffers respectively connected to the plurality of memory cells through a plurality of bit lines;
• and
• a memory controller configured to control the memory device to perform a program operation when a write request is received from the outside,
• wherein the program operation includes a plurality of program loops each including a program voltage apply operation of applying a program voltage to selected memory cells among the memory cells and a verify operation of verifying a program state of the selected memory cells,
• wherein each of the plurality of page buffers includes:
• a first latch configured to store a verify result according to a verify operation of an nth program loop among the plurality of program loops;
• and
• a second latch configured to store a verify result according to a verify operation of an (n−1)th program loop among the plurality of program loops, and
• wherein bit line voltages to be respectively applied to the bit lines in an (n+1)th program loop among the plurality of program loops are determined based on the verify results stored in the first latch and the second latch.