Integrated circuit memory with write assist

Abstract

An integrated circuit memory includes memory cellsis connected to a power supply Vdd via a power supply control circuit. The power supply control circuit includes a first gateand a second gate. The first gateis switched by a write assist circuit so as to be non-conductive when writing to the memory cell. The second gateis conductive both when writing to the memory celland when not writing to the memory cell. Accordingly, when a write operation is made a relatively high resistance path is formed through the power supply control circuitcompared to when writing is not being performed. This increase in the resistance through the power supply control circuitduring write operations induces a dip in the virtual supply voltage provided at the supply output of the power supply control circuitin a manner which assist writes to be made. If individual memory cellstend to resist changes in their state more strongly, then they will tend to draw more current which will in turn result in a larger virtual supply voltage dip which will assist more strongly in encouraging those memory cellsto change state.