US 9,805,800 B1 · Electrically programmable read only memory devices having uniform program characteristic and methods of programming the same

Abstract

An EPROM device includes bit lines branching from a supply voltage line, a first group of enablement signal lines intersecting the bit lines, unit cells respectively located at cross points of the bit lines and the first group of enablement signal lines, pass transistors, load transistors, comparators, and enablement signal generators. One of the pass transistors and one of the load transistors are coupled in series between the supply voltage line and each of the bit lines. Each of the comparators receives voltages of both ends of any one of the load transistors to generate an output signal. Each of the enablement signal generators receives one of the output signals of the comparators and one of a second group of enablement signals and outputs one of a third group of enablement signals to turn off one of the pass transistors responsive to a program current reaching a reference value.

Claims17

Dependent claims

An electrically programmable read only memory (EPROM) device comprising:

a plurality of bit lines branching from a supply voltage line;
a first group of enablement signal lines intersecting the plurality of bit lines;
a plurality of unit cells respectively located at cross points of the plurality of bit lines and the first group of enablement signal lines;
a plurality of pass transistors and a plurality of load transistors, wherein one of the pass transistors and one of the load transistors are coupled in series between the supply voltage line and each of the plurality of bit lines;
a plurality of comparators, each of which is configured to receive voltages of both ends of any one of the load transistors to generate an output signal;
and
a plurality of enablement signal generators, each of which is configured to receive one of the output signals of the comparators and one of a second group of enablement signals and configured to output one of a third group of enablement signals to turn off one of the pass transistors if a program current of any one of the unit cells selected from the plurality of unit cells reaches a reference program current.

4 more elements

A method of programming an electrically programmable read only memory (EPROM) device including a plurality of bit lines branching from a supply voltage line, a first group of enablement signal lines intersecting the plurality of bit lines, a plurality of unit cells respectively located at cross points of the plurality of bit lines and the first group of enablement signal lines, and a plurality of pass transistors and a plurality of load transistors, wherein one of the pass transistors and one of the load transistors are coupled in series between the supply voltage line and each of the plurality of bit lines, the method comprising:

detecting voltages of both ends of one of the load transistors, which is connected to any one of the unit cells selected from the plurality of unit cells during a program operation of the selected unit cell;
comparing the detected voltages to evaluate a program current flowing through the selected unit cell;
and
turning off the pass transistor connected to the selected unit cell to terminate the program operation, if the program current reaches a reference program current.

1 more element

Dependencies are inferred from the claim text.

Electrically programmable read only memory devices having uniform program characteristic and methods of programming the same

Life of this patent

Electrically programmable read only memory devices having uniform program characteristic and methods of programming the same

Life of this patent

Abstract

Claims17