Date post: | 15-Apr-2017 |
Category: |
Documents |
Upload: | keerthi-thallam |
View: | 64 times |
Download: | 0 times |
Performance Analysis of Low Power High Speed Hybrid
Adder
By Thallam KeerthiUnder Guidance of Mrs.Namitha PalechaRVCE VLSI Design and Embedded systems
OverviewOverview
Purpose Review Of Full Adder Design Of Different Logic Styles Proposed Hybrid Adder Presentation Performance Analysis Cadence Implementation Simulation Results Takeaways
PurposePurpose
To minimize the power, increase the speed Which full adder topology does this the best?
Can we make any generalizations in those decisions?
StaticTransmission
Gates
CPL
Static Full Static Full AddersAdders
Static CMOS• Transistor Count: 28• High Capacitance and
need of input buffersCPL• Transistor Count: 32• Area inefficiency
Transmission Logic Transmission Logic AddersAdders
TGA:Transistor Count: 20Power Dissipation: 7.87microwattsDelay: 301.3ps
Hybrid Full Adder ImplementationHybrid Full Adder Implementation
Full Adder is implemented as the combination of 3 modules
Module 1 – Generation of XOR-XNOR module Module 2 – Sum Generation Module 3 – Carry Generation
Comparison of XNOR-XOR ModuleComparison of XNOR-XOR Module
Referred XOR-XNOR ModulePresenting XOR-XNOR Module
Proposed Hybrid AdderProposed Hybrid Adder
A
B XNOR
Condition
0 0 1 strong
0 1 0 weak
1 0 0 strong
1 1 1 weak
Power CalculationPower Calculation
•Dynamic Power Dissipation Contributes to the major power consumption
Voltage Power Consumption
1.8V 2.94μW
1.2V 1.456μW
0.9V 818.2nW
Delay of Hybrid AdderDelay of Hybrid Adder
Critical Path for Delay is the path from Carry-in to Carry-out
Techniques to reduce the delay• Reduce the path between carry-in and carry-out• Increase the width of transistor to decrease the delay. FAST CIRCUITS OCCUPY MORE AREA
Voltage Delay
1.8V 61.4ps
1.2V 112.7ps
0.9V 154.6ps
Comparison with other Hybrid AdderComparison with other Hybrid Adder
•Transistor Count: 22•Maintains Proper Voltage Swing
Take Away:•Transistor Count increased•Delay is increased•Power Consumption increased•Area increased
Simulation ResultsSimulation Results
Simulation ResultsSimulation ResultsAt 1.8V DC Voltage Supply
Simulation ResultsSimulation ResultsAt 1.2V DC Supply Voltage
Simulation ResultsSimulation ResultsAt 0.9V DC Supply Voltage
Any Questions?