WRITING CIRCUIT OF NONVOLATILE SEMICONDUCTOR MEMORY ELEMENT

摘要

PURPOSE:To always impress a fixed level of a voltage to the source of a memory element and at the same time to decrease the number of IGFETs by compensating the fluctuation of a current flowing through the memory element. CONSTITUTION:If a current IM2 flowing through the memory element Mb1 has fluctuation in a writing mode, the voltage of a VS2 has the fluctuation. This voltage fluctuation of the VS2 is amplified by a forward inverter consisting of an R1 and an IGFET-Mb3 and then converted into the variation of conductance gm of an IGFET-Mb2. As a result, the voltage fluctuation of the VS2 is suppressed extremely to the fluctuation of the IM2. Thus the VS2 is kept at the fixed level of the voltage.