To check the programming of a nonvolatile memory cell storing an actual threshold value, the drain terminal of the cell is biased at a constant voltage; the gate terminal is biased at a check voltage; the cell is supplied with a predetermined current to determine a gate-source voltage drop related to...http://www.google.de/patents/US5880993?utm_source=gb-gplus-sharePatent US5880993 - Method and circuit for checking multilevel programming of floating-gate nonvolatile memory cells particularly flash cells
