Sense line charging system for random access memory

Abstract

A random access memory includes a column of static MOS storage cells. Two sense-write conductors are coupled to each cell in the column. Each sense-write conductor is also coupled, respectively, to a termination MOSFET. The first sense-write conductor of each column of storage cells is coupled by means of a first coupling MOSFET to a first bit-sense conductor. The second sense-write conductor of each column of storage cells is coupled, by a second MOSFET to a second bit-sense conductor. Each pair of sense-write conductors is coupled to a V.sub.DD conductor by a separate charging MOSFET having its gate electrode coupled to a circuit for generating a pulse at the end of a write cycle. Since at the end of any write operation, the two bit-sense conductors and the two sense-write conductors of the selected column will be at opposite voltage levels, the pulse very rapidly precharges the voltages of the two sense-write conductors and of the two bit-sense conductors to levels which ensure that the data stored in the storage cell next selected will not be destroyed as a result of the opposite voltage levels of the two bit-sense conductors acting to write an undesired state into the storage cell selected next. The read access time of the memory is reduced by the amount of time required by the termination MOSFETS to charge a sense-write conductor and a bit-sense conductor to a MOSFET threshold drop below V.sub.DD minus the time required for the charging MOSFETs to precharge the sense-write and bit-sense conductors.