Low Voltage Register File Cell Structure

A register file comprising:

• a plurality of bit cells arranged in M subsets each having N bit cells, wherein each of the N bit cells includes:
• a first inverter and a second inverter, wherein an output of the first inverter is coupled to an input of the second inverter and wherein an output of the second inverter is coupled to an input of the first inverter, wherein each of the first and second inverters are coupled to receive power from a virtual voltage node that is unique to that subset of the N bit cells;
• and
• wherein each of the M subsets includes a transistor stack having a plurality of transistors coupled in series between the virtual voltage node of that subset and a global voltage node, wherein the transistor stack is configured to pull a voltage on the virtual voltage node toward a voltage present on the global voltage node.

An integrated circuit comprising:

• an execution unit configured to execute instructions;
• a register file configured to store operands for instructions to be executed by the execution unit, and further configured to store results of instructions executed by the execution unit, wherein the register file includes:
• a plurality of bit cells arranged in M subsets each having N bit cells, wherein each of the N bit cells includes:
• a first inverter and a second inverter, wherein an output of the first inverter is coupled to an input of the second inverter and wherein an output of the second inverter is coupled to an input of the first inverter, wherein each of the first and second inverters are coupled to receive power from a virtual voltage node that is unique to that subset of the N bit cells;
• and
• wherein each of the M subsets includes a transistor stack coupled between the virtual voltage node of that subset and a global voltage node, the transistor stack comprising a plurality of series-coupled transistors, wherein the transistor stack is configured to pull a voltage on the virtual voltage node toward a voltage present on the global voltage node.