Dual-Voltage Supply for Power ReductionProblem StatementPower and DelayApproachThings to watch4 x 4 MultiplierMultiplier CellLow-Voltage Supply AssignmentSlide 9Percentage of the Circuit with Reduced Voltage SupplyExperimental Results for a CellExperimental Results for a 4 x 4 MultiplierA Single Inverter4 x 4 bit array MultiplierPower EstimationSlide 1632 x 32 bit array MultiplierSlide 18Slide 19ConclusionCommentsDecember 1, 2005December 1, 2005ELEC 6970 - Project PresentationELEC 6970 - Project Presentation11Dual-Voltage Supply for Dual-Voltage Supply for Power ReductionPower ReductionELEC 6970 – Low Power DesignELEC 6970 – Low Power DesignProject PresentationProject PresentationbybyMuthubalaji RamkumarMuthubalaji RamkumarDecember 1, 2005December 1, 2005ELEC 6970 - Project PresentationELEC 6970 - Project Presentation22Problem StatementProblem Statement To Use a dual-supply voltage in order to To Use a dual-supply voltage in order to reduce the power consumption of the 32 reduce the power consumption of the 32 x 32 bit integer array multiplier circuit x 32 bit integer array multiplier circuit without compromising the overall delaywithout compromising the overall delayDecember 1, 2005December 1, 2005ELEC 6970 - Project PresentationELEC 6970 - Project Presentation33Power and DelayPower and Delay Power Power → → VDD2Delay Delay → → KVDD───────(V(VDDDD – V – Vtt))ααDecember 1, 2005December 1, 2005ELEC 6970 - Project PresentationELEC 6970 - Project Presentation44ApproachApproachLow Voltage Assignment to as many cells as Low Voltage Assignment to as many cells as possiblepossibleThe interconnections in this multiplier circuit The interconnections in this multiplier circuit makes it difficultmakes it difficultTherefore assign Low Voltage Supply to as many Therefore assign Low Voltage Supply to as many gates as possiblegates as possibleDecember 1, 2005December 1, 2005ELEC 6970 - Project PresentationELEC 6970 - Project Presentation55Things to watchThings to watchReducing the Voltage Supply will increase the Reducing the Voltage Supply will increase the delay of a gatedelay of a gateTherefore assign Low-Voltage Supply only to the Therefore assign Low-Voltage Supply only to the gates which do not have any influence on the gates which do not have any influence on the Critical Path Delay directly or indirectlyCritical Path Delay directly or indirectlyLow voltage gate should have adequate voltage Low voltage gate should have adequate voltage swing in order to drive a High Voltage gate its swing in order to drive a High Voltage gate its feeding in to.feeding in to.December 1, 2005December 1, 2005ELEC 6970 - Project PresentationELEC 6970 - Project Presentation664 x 4 Multiplier4 x 4 Multiplier000000 0 0A0A1A2A3B3 B2 B1 B0Y0Y1Y2Y3Y4Y5Y6Y7FulladderBACarry inSum outputSum inputCarry outArrayCellDecember 1, 2005December 1, 2005ELEC 6970 - Project PresentationELEC 6970 - Project Presentation77Multiplier CellMultiplier CellDecember 1, 2005December 1, 2005ELEC 6970 - Project PresentationELEC 6970 - Project Presentation88Low-Voltage Supply AssignmentLow-Voltage Supply AssignmentOutput Cells Output Cells along the along the edgeedgeN-1N-1G4G4First RowFirst Row3(N-1)3(N-1)G1,G2,G3G1,G2,G3Second Row Second Row to Last Rowto Last RowN(N-1)N(N-1)G1G1Left ColumnLeft Column2(N-1)2(N-1)G2,G3G2,G3December 1, 2005December 1, 2005ELEC 6970 - Project PresentationELEC 6970 - Project Presentation99Total Number of gates = 6NTotal Number of gates = 6N22Number of gates with Low Voltage Number of gates with Low Voltage assignment = (N-1)(N+6) assignment = (N-1)(N+6)  Percentage of the circuit with Reduced VPercentage of the circuit with Reduced VDD DD ==(N-1)(N+6) / 6N(N-1)(N+6) / 6N22December 1, 2005December 1, 2005ELEC 6970 - Project PresentationELEC 6970 - Project Presentation1010Percentage of the Circuit with Percentage of the Circuit with Reduced Voltage SupplyReduced Voltage Supply0 20 40 60 80 100 120 14016182022242628303234N - No of bitsPercentage of Gates under Low Voltage SupplyDecember 1, 2005December 1, 2005ELEC 6970 - Project PresentationELEC 6970 - Project Presentation1111Experimental Results for a CellExperimental Results for a CellVoltage Voltage (Volts)(Volts)PPdyn dyn (Microwatts)(Microwatts)PPstaticstatic (Picowatts)(Picowatts)DelayDelay(Sec)(Sec)1.81.89.19.1246246251 p251 p1.51.55.275.27171171358 p358 p1.21.22.872.87112112537 p537 p0.90.90.790.7967671.14 n1.14 nDecember 1, 2005December 1, 2005ELEC 6970 - Project PresentationELEC 6970 - Project Presentation1212Experimental Results for a Experimental Results for a 4 x 4 Multiplier4 x 4 MultiplierVoltage Voltage (Volts)(Volts)PPdyn dyn (Microwatts)(Microwatts)PPstaticstatic (Nanowatts)(Nanowatts)DelayDelay(Sec)(Sec)1.81.82132131.61.61.57 n1.57 n1.51.5132.1132.11.131.131.76 n1.76 n1.21.275.875.80.750.751.97 n1.97 n0.90.936.436.40.460.462.2 n2.2 nDecember 1, 2005December 1, 2005ELEC 6970 - Project PresentationELEC 6970 - Project Presentation1313A Single InverterA Single InverterVoltage Voltage (Volts)(Volts)PPdyn dyn (Microwatts)(Microwatts)PPstaticstatic (Picowatts)(Picowatts)DelayDelay(Sec)(Sec)1.81.81.881.88101082 p82 p1.51.50.5880.5887791 p91 p1.21.20.1140.1144.64.6108 p108 p0.90.90.0470.0472.82.8236 p236 pDecember 1, 2005December 1, 2005ELEC 6970 - Project PresentationELEC 6970 - Project Presentation14144 x 4 bit array Multiplier4 x 4 bit array MultiplierN=4N=4Total Number of Gates = 6N2 = 6(16) = 96Number of Gates with Low VNumber of Gates with Low VDD DD = (N-1)(N+6) = (N-1)(N+6) = (3)(10) = = (3)(10) = 30 = 31.25 %30 = 31.25 %Number of Gates with Normal VNumber of Gates with Normal VDDDD = = 96 – 30 = 96 – 30 = 66 = 68.75%66 = 68.75%December 1, 2005December 1, 2005ELEC 6970 - Project PresentationELEC 6970 - Project Presentation1515Power EstimationPower EstimationUsing Dual-Voltages, Using Dual-Voltages, 1.8V & 1.5V1.8V & 1.5VPower Consumption = Power Consumption = (0.3125)(132.1uW) + (0.6875)((0.3125)(132.1uW) + (0.6875)(213uW213uW))= = 187.73 uW187.73 uW12%12% Power Reduction Power ReductionDecember 1, 2005December 1, 2005ELEC 6970 - Project PresentationELEC 6970 - Project Presentation1616Power EstimationPower EstimationUsing Dual-Voltages, Using Dual-Voltages, 1.8V & 1.2V1.8V & 1.2VPower Consumption = Power Consumption = (0.3125)(75.8uW) +