Subthreshold standard cell library

Patent metadata

Field	Value
Publication number	US-9529953-B2
Application number	US-201615049762-A
Country	US
Kind code	B2
Filing date	Feb 22, 2016
Priority date	Aug 2, 2012
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

A subthreshold standard cell library addresses the energy efficiency of electronic systems, thereby significantly reducing power consumption. Recent energy performance requirements are causing the next-generation system manufacturers to explore approaches to lower power consumption. Subthreshold operation has been examined and implemented in designing ultra-low power standard cell designs that operate beyond the normal modes of operation, with the potential for large energy savings. Operation of CMOS (Complementary Metal Oxide Semiconductor) transistors in the subthreshold regime, where the supply voltage used in operation is orders of magnitude below the normal operating voltage of typical transistors, has proven to be very beneficial for energy constrained systems as it enables minimum energy consumption in Application Specific Integrated Circuits (ASICs).

First claim

What is claimed is:

1. A standard cell logic library for synthesizing an application specific integrated circuit (ASIC), said library comprising:
a plurality of logic gates, each of said logic gates having a rise delay, a fall delay, a propagation delay rise, and a propagation delay fall, and operating in the subthreshold voltage region;
said logic gates each including different combinations and quantities of n-type and p-type metal oxide semiconductor (nMOS and pMOS) transistors, each said nMOS and each said pMOS transistor further having a constant channel length and a nMOS to pMOS ratio R that will minimize average power consumption during operation in said subthreshold region;
said ratio R being defined b W n /W p , where W n is the total channel width W n of said nMOS transistors, and W p is the total channel width of said pMOS transistors;
said ratio R being chosen so that the rise delay and the fall delay of each said logic gate of said ASIC are substantially equal and so that the propagation delay rise and the propagation delay fall of each said logic gate of said ASIC are substantially equal;
an operating V dd component including positive supply voltages in the subthreshold voltage region for the respective integrated circuits for said ASIC;
a synthesis library input component including timing, temperature and physical characteristics of the respective integrated circuits for said ASIC; and
a physical library component including symbol, schematic and mask layouts for the respective circuits for said ASIC.

2. The logic library of claim 1 wherein the subthreshold region includes a subthreshold voltage characterized by approximately 10-20% of nominal bias voltage.

3. The logic library of claim 2 wherein the logic gates include one or more of the group of inverter, tri-state inverter, 3 input NAND, 2 input NAND, 2 input AND, 2 input NOR, 2 input OR, buffer, D latch, and a D flip flop logic gates.

4. A method for manufacturing an application specific integrated circuit (ASIC) for operation in the subthreshold region, said method comprising the steps of:
A) establishing a plurality of standard logic gates, each said logic gate having an assigned logic function and a plurality of n-type Metal Oxide Semiconductor (nMOS) and p-type Metal Oxide Semiconductor (pMOS) transistors, each said nMOS transistor having an channel width W n and a channel length L n , each pMOS transistor having a channel width W p , and a channel length L p ;
B) for each said standard logic gate in said step A), determining a ratio R of W n /W p that will minimize the average power consumption, while at the same time maintaining channel length L n and said channel length L p constant and equal to each other;
said ratio R being defined by W n /W p , where W n is the total channel width W n of said nMOS transistors and W p is the total channel width of said pMOS transistors;
said ratio R being chosen so that the rise delay and the fall delay of each said logic gate of said ASIC are substantially equal and so that the propagation delay rise and the propagation delay fall of each said logic gate of said ASIC are substantially equal;

and,
C) synthesizing said ASIC using said standard logic gates from said step B).

Assignees

• Kamin Nackieb M
• Lum Gregory
• Au Henry
• Us Navy

Inventors

• Kamin Nackieb M
• Lum Gregory
• Au Henry

Classifications

• G06F30/3312 Primary

  Timing analysis · CPC title

• G06F30/327 Primary

  Logic synthesis; Behaviour synthesis, e.g. mapping logic, HDL to netlist, high-level language to RTL or netlist · CPC title

• G06F2119/08

  Thermal analysis or thermal optimisation · CPC title

• G06F30/398

  Design verification or optimisation, e.g. using design rule check [DRC], layout versus schematics [LVS] or finite element methods [FEM] (optical proximity correction [OPC] design processes G03F1/36) · CPC title

• G06F2115/08

  Intellectual property [IP] blocks or IP cores · CPC title