Multi-step read pass voltage discharge for ICC reduction

A method for reading memory cells in a three dimensional memory structure, the method comprising:

• applying a read reference voltage to a selected word line connected to selected memory cells in a selected block, wherein the selected block comprises word lines and NAND strings having memory cells, each word lines in the selected block connected to a memory cell of each NAND string in the block;
• applying a read pass voltage to unselected word lines in the selected block while applying the read reference voltage to the selected word line, wherein the unselected word lines are connected to unselected memory cells;
• sensing the selected memory cells while the read pass voltage is applied to the unselected word lines and the read reference voltage is applied to the selected word line;
• discharging a voltage on the unselected word lines from the read pass voltage to an intermediate positive voltage in a first stage after sensing the selected memory cells;
• and
• discharging a voltage on the unselected word lines from the intermediate positive voltage to a final positive voltage in a second stage.

A non-volatile storage system, comprising:

• a three-dimensional memory structure having a plurality of NAND strings having memory cells, the three-dimensional memory structure having word lines connected to the memory cells;
• means for sensing selected memory cells connected to a selected word line in the three-dimensional memory structure, including means for applying a read pass voltage to unselected word lines in the three-dimensional memory structure and means for applying a read reference voltage to the selected word line;
• means for discharging the read pass voltage on the unselected word lines in multiple stages after sensing the selected memory cells, including:
• discharging a voltage on the unselected word lines from the read pass voltage to a positive intermediate voltage while increasing a voltage on the selected word line from the read reference voltage to the positive intermediate voltage in a first stage of the multiple stages;
• and
• discharging a voltage on the unselected word lines and the selected word line together from the positive intermediate voltage to a final positive voltage in a second stage of the multiple stages.