Patent ID: 6717848
Filing Date: 2004-04-06
Classification: G11C

Abstract:
A sensing circuit in a multi-level flash memory cell, comprising:a multi-level flash memory cell having a flash memory cell and a capacitor connected to a source of the flash memory cell; a first sense amplifier for comparing a state of said multi-level flash memory cell with a first reference cell; a second sense amplifier for comparing a state of said multi-level flash memory cell with a second reference cell; a third sense amplifier for comparing a state of said multi-level flash memory cell with a third reference cell; a logical means for logically combining a sensing enable signal and an output signal of said first sense amplifier; first and second switching means for supplying the power supply voltage, respectively, depending on an output signal of said logical means and its inverted signal; a third switching means for connecting said second reference cell and said multi-level flash memory cell to said second sense amplifier, depending on the power supply voltage supplied by said first switching means; and a fourth switching means for connecting said third reference cell and said multi-level flash memory cell to said third sense amplifier, depending on the power supply voltage supplied by said second switching means.