Minimization of circuit delay and power through transistor sizing

In a programmed digital computer, a method of minimizing signal delay and power consumption of an original circuit, wherein the original circuit includes a plurality of circuit paths constructed from transistors and nodes, said method comprising:

• inputting a netlist of an original circuit into said computer, said original circuit including a plurality of circuit paths and transistors included in these paths;
• generating a scaling circuit from said netlist of said original circuit, said scaling circuit having transistor widths that are scaled values of transistor widths in said original circuit;
• generating a changing circuit from said netlist of said original circuit, said changing circuit having transistor widths that are uniform;
• determining a time delay of each path of each of said original, scaling, and changing circuits, wherein a time delay of greatest value of each of said original, scaling, and changing circuits is associated with a critical path of each of said original, scaling, and changing circuits;
• selecting a first transistor of each of said original, scaling, and changing circuits of predetermined size, said first transistor of each of said original, scaling, and changing circuits residing in a first path in each of said original, scaling, and changing circuits, each of said original, scaling, and changing circuits having a first time delay and having a first node being coupled to said first transistor of each of said original, scaling, and changing circuits;
• simulating operation of said original, scaling, and changing circuits;
• counting state switches of said first node of said original, scaling, and changing circuits during said simulating;
• generating an alternative circuit from said netlist of said original circuit, said alternative circuit having transistor widths that are different from transistor widths of said original, scaling, and changing circuits, if said original, scaling, and changing circuits exhibit poor performance based on user-selected criteria;
• determining a time delay of each path of said alternative circuit, wherein a time delay of greatest value of said alternative circuit is associated with a critical path of said alternative circuit;
• selecting a first transistor of alternative circuit of predetermined size, said first transistor of said alternative circuit residing in a first path in said alternative circuit, said alternative circuit having a first time delay and having a first node being coupled to said first transistor of said alternative circuit;
• simulating operation of said alternative circuit;
• counting state switches of said first node of said alternative circuit during said simulating;
• and
• resizing said first transistor of said alternative circuit based upon a number of state switches occurring at said first node of said alternative circuit, wherein said resizing includes:
• increasing the size of said first transistor of said alternative circuit when said first time delay normalized to the time delay of greatest value exceeds a predetermined threshold value;
• and
• decreasing the size of said first transistor of said alternative circuit when said first time delay normalized to the time delay of greatest value is less than said predetermined threshold value.

In a programmed digital computer, a method of minimizing signal delay and power consumption of a selected circuit, wherein the selected circuit includes a plurality of circuit paths constructed from transistors and nodes, said method comprising:

• determining a time delay of each path in said selected circuit, wherein a time delay of greatest value is associated with a critical path of said selected circuit;
• selecting a first transistor of predetermined size, said first transistor residing in a first path in said selected circuit, said selected circuit having a first time delay and having a first node being coupled to said first transistor;
• simulating operation of said selected circuit;
• counting state switches of said first node of said selected circuit during said simulating;
• estimating wiring capacitance of said first node in said selected circuit based upon fanin and fanout and area of said first node;
• and
• resizing said first transistor based upon a number of state switches occurring at said first node, wherein said resizing includes:
• increasing the size of said first transistor when said first time delay normalized to the time delay of greatest value exceeds a predetermined threshold value;
• and
• decreasing the size of said first transistor when said first time delay normalized to the time delay of greatest value is less than said predetermined threshold value.