Patent ID: 6972614
Filing Date: 2005-12-06
Classification: G11C

Abstract:
1. An identification circuit for establishing and sensing the state of a fusible element used in on chip type identification comprising: a circuit establishing control signals for enabling the identification circuit for sensing with an initiating signal, which signal remains off during a personalization of the fusible element; dual paths energized by said control signals generated by a level setting circuit to energize one path through the fusible element to provide a state level and another path through a reference path that provides a reference voltage level that is distinguishable from both the blown and unblown states of the fusible element; a differential sensing circuit for comparing said reference voltage level to said state level to provide a signal indicating a state of the fusible element; and protection circuitry changing voltage levels on said dual paths and said differential sensing circuit to protect said circuit during an operation in which the state of the fusible element is set.