Non-volatile semiconductor storage device and method of reading out data

#1. Field of the Invention

#The present invention relates to non-volatile semiconductor storage devices, in particular to a non-volatile semiconductor storage device operating under a method of reading out data from a cell of the virtual ground type, and a method of reading out data.

#2. Description of the Related Art

#Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings, in which:

#FIG. 1 is a circuit diagram showing the principle of the present invention;

#FIG. 2 is a wave form chart showing the principle of the present invention and operations according to one embodiment of the present invention; and

#FIG. 1 is a circuit diagram showing the principle of the present invention. FIG. 1 shows one memory cell 1 and a circuit construction around such memory cell 1.

#The memory cell 1 is a non-volatile transistor that is electrically programmable and electrically erasable. The memory cell 1 includes a source, a drain, a control gate, and a floating gate.

#The drain of the memory cell 1 is connected to a positive supply voltage VCC via a transistor 2a of Y decoder and a transistor 3 of a load part. The transistor 3 is turned on when receiving a low-level load signal PD. The transistor 2a is turned on when receiving a high-level select signal YSEL. The memory cell 1 is turned on when receiving a high-level word line drive signal WL.