Current-sensed Interconnects: Static Power Reduction and Sensitivity to Temperature

................................................................................................................vii ACKNOWLEDGMENTS ............................................................................................vi 1 BACKGROUND ........................................................................................................1 1.1 Interconnect Circuit Challenge ........................................................................1 1.2 Existing Interconnect Circuits .........................................................................3 1.3 Differential Current Sensing............................................................................4 1.4 Thermal Impact on Interconnect......................................................................6 2 ANALYTICAL AND EXPERIMENT APPROACH.................................................9 2.1 HSPICE Model ................................................................................................9 2.1.1 Wire Model ...........................................................................................9 2.1.2 Device Model......................................................................................14 2.2 Circuit Simulation..........................................................................................16 2.2.2 Repeater Circuit ..................................................................................16 2.2.2 Repeater Insertion Optimization.........................................................17 2.2.3 Differential Current Sensing...............................................................19 2.3 Experiment Setup...........................................................................................25 3 ENERGY-AWARE DIFFERENTIAL CURRENT SENSING................................27 3.1 Energy-aware Differential Current Sensing ..................................................27 3.2 Experimental Setup........................................................................................32 3.3Repeater Optimization ....................................................................................32 3.4. Results and Discussion..................................................................................35 3.4.1 First Order Comparison.......................................................................35 3.4.2 Activity Factor Impact.........................................................................36 3.4.3 Wire Length Impact.............................................................................37 3.4.4 Driver Size Impact...............................................................................40 3.4.5 Technology Scaling Impact.................................................................42 3.4.6 Signaling Complixity and Area Efficiency..........................................44 3.5 Conclusions....................................................................................................45