Programmable read only memory with output indicating programming state

U.S. Patent Number: 5392418

Abstract: A non-volatile memory cell including a pn diode and a circuit for sensing the logic state of the pn diode such that a logic one state indicates that the diode is in its normal state, while the other logic state is created by fusing the diode for creating a short circuit. The circuit for sensing the logic state of the diode includes a circuit for developing a sense voltage across the diode, a first comparator for comparing the sense voltage with a first reference voltage greater than the normal junction voltage, a second comparator for comparing the sense voltage with a second reference voltage less than the normal junction voltage but greater than the fused junction voltage and a circuit responsive to the outputs of the first and second comparators to provide an output signal which has a first value if the sense voltage is between the first and second reference voltages and a second value if the sense voltage is not between the first and second reference voltages.

Inventors: Burri; Michel (Gd Saconnex, CH)

Assignee: Motorola, Inc. (Schaumburg, IL)

Application Number: 07/837,189

Issued: 1995-02-21

Expired: 2007-02-21

Classes: 365/244 ; 365/104; 365/105; 365/96

Field of search: 395/400,425 365/96,104,105

Click the image above to view patent images at uspto.gov within a frame.

Click here for the fulltext page on uspto.gov within a frame.