Abstract: A register file cell structure to enable lower voltage writes is disclosed. In one embodiment, a register file includes a state element made up of two cross-coupled inverters. Each of the inverters includes a p-channel metal oxide semiconductor (PMOS) transistor having a source terminal coupled to a virtual voltage node. One or more PMOS transistors are coupled in series between the virtual voltage node and a global voltage node. Each of the one or more PMOS transistors includes a gate terminal that is hardwired to a ground node, and thus these devices remain active when power is applied to the global voltage node. The presence of the one or more PMOS devices coupled between the virtual and global voltage nodes results in the ability to overwrite contents stored in the state element at lower voltages than otherwise attainable without the one or more PMOS devices.

Abstract: A memory circuit may include a pair of cross-coupled inverters configured to store a bit of data and a first transistor coupled to a first node of the pair of cross-coupled inverters. A plurality of transistors that form the pair of inverters have a first nominal threshold voltage. The first transistor is coupled to a first bit line, and has a second nominal threshold voltage that is lower than the first nominal threshold voltage. The first transistor may be a write transistor and another write transistor having the second nominal threshold voltage is coupled to the other node of the pair of cross-coupled inverters. A register file may include a bit storage section that includes at least one pair of the cross-coupled inverters; a write transistor section and a read transistor section having the second nominal threshold voltage.

Abstract: In one embodiment, a memory circuit comprises a pair of cross-coupled inverters configured to store a bit of data and a first transistor coupled to a first node of the pair of cross-coupled inverters. A plurality of transistors that form the pair of inverters have a first nominal threshold voltage. The first transistor is coupled to a first bit line, and has a second nominal threshold voltage that is lower than the first nominal threshold voltage. More specifically, in one embodiment, the first transistor is a write transistor and another write transistor having the second nominal threshold voltage is coupled to the other node of the pair of cross-coupled inverters.