Patent ID: 7688635
Filing Date: 2010-03-30
Classification: G11C

Abstract:
1. A method of sensing a threshold voltage of a non-volatile memory cell, comprising: placing a read voltage on a control gate of a selected non-volatile memory cell; coupling the selected non-volatile memory cell to a source line and a bit line; providing a current from a current source to the bit line coupled to the selected non-volatile memory cell while the read voltage is placed on the control gate of the selected non-volatile memory cell, wherein the current from the current source is selected to be sufficient to charge the bit line if the selected non-volatile memory cell is deactivated in response to the read voltage and to be insufficient to charge the bit line if the selected non-volatile memory cell is activated in response to the read voltage; using the current from the current source while the read voltage is placed on the control gate of the selected non-volatile memory cell, increasing a voltage level of the bit line if the selected non-volatile memory cell is deactivated in response to the read voltage; sensing the voltage level of the bit line to determine the threshold voltage level of the selected non-volatile memory cell; and using the sensing of the voltage level of the bit line to selectively isolate the selected non-volatile memory cell from the current source.