SENSE AMPLIFIER CIRCUIT

摘要

PURPOSE: A sense amplifier circuit is provided to improve high voltage sensing margin by converting the load ratio of a data output node in a reference memory cell in case of a source voltage over a certain source voltage. CONSTITUTION: A third PMOS transistor(P13) is connected between a source voltage terminal(Vcc) and a second node(K12) outputting the data of a reference memory cell(M12). Herein, the third PMOS transistor receives the output voltage of a source voltage detect circuit(14) passing through an inverter(I11). The load ratio of the second node is changed according to the output voltage of the source voltage detect circuit. When the source voltage is under a detect level, the output voltage of the source voltage detect circuit becomes low for enabling the second node. When the source voltage is over the detect level, the output voltage of the source voltage detect circuit becomes high for disabling the second node. The third PMOS transistor is turned on for a sense amplifier(11) to have different load from the load of low voltage.