Low power vlsi design
-
Upload
vinchipsytm-vlsitraining -
Category
Documents
-
view
10.077 -
download
0
Transcript of Low power vlsi design
![Page 1: Low power vlsi design](https://reader036.fdocuments.us/reader036/viewer/2022082605/555e6d06d8b42a34098b4e2d/html5/thumbnails/1.jpg)
LOW POWER VLSI DESIGN
Vinchip Systems(a Design and Verification Company)
Chennai.
![Page 2: Low power vlsi design](https://reader036.fdocuments.us/reader036/viewer/2022082605/555e6d06d8b42a34098b4e2d/html5/thumbnails/2.jpg)
Introduction
Due to integration of components increased the power
comes in lime light
It is much important that handheld devices must possess
low power devices
For better performance
For long run time (Battery time)
![Page 3: Low power vlsi design](https://reader036.fdocuments.us/reader036/viewer/2022082605/555e6d06d8b42a34098b4e2d/html5/thumbnails/3.jpg)
Definition
Power Dissipation:
The rate of energy which is taken from the source and
converted into heat
![Page 4: Low power vlsi design](https://reader036.fdocuments.us/reader036/viewer/2022082605/555e6d06d8b42a34098b4e2d/html5/thumbnails/4.jpg)
Types of Power Dissipation
Static power dissipation
Due to leakage current
Dynamic Power dissipation
Due to switching activities of transistor
![Page 5: Low power vlsi design](https://reader036.fdocuments.us/reader036/viewer/2022082605/555e6d06d8b42a34098b4e2d/html5/thumbnails/5.jpg)
Low Power Strategies
![Page 6: Low power vlsi design](https://reader036.fdocuments.us/reader036/viewer/2022082605/555e6d06d8b42a34098b4e2d/html5/thumbnails/6.jpg)
Low Power Design Space
Three parts that we can perform low power
techniques to reduce power dissipation
Voltage
Physical Capacitance
Switching activity
![Page 7: Low power vlsi design](https://reader036.fdocuments.us/reader036/viewer/2022082605/555e6d06d8b42a34098b4e2d/html5/thumbnails/7.jpg)
Supply voltage reduction
Voltage reduction offers an effective means of power reduction
A factor of two reduction in supply voltage yields a factor of four
decreases in power consumption
But the performance is also getting reduced
To avoid the above stated problem,
Threshold voltage should be scaled down
![Page 8: Low power vlsi design](https://reader036.fdocuments.us/reader036/viewer/2022082605/555e6d06d8b42a34098b4e2d/html5/thumbnails/8.jpg)
Physical Capacitance
Dynamic power consumption depends linearly on the physical capacitance being switched
So minimizing capacitance offers another technique to for minimizing power consumption
The capacitor can be kept as small by.. Minimum logic Smaller devices Fewer and shorter wires
![Page 9: Low power vlsi design](https://reader036.fdocuments.us/reader036/viewer/2022082605/555e6d06d8b42a34098b4e2d/html5/thumbnails/9.jpg)
Switching Activity
There are two components to switching activity :
which determines the average periodicity of data arrivals
E (sw) which determines how many transitions each arrival will generate
Switching activity is reduced by
Selecting proper algorithms architecture optimization,
Proper choice of logic topology
Logic level optimization which results in less power
![Page 10: Low power vlsi design](https://reader036.fdocuments.us/reader036/viewer/2022082605/555e6d06d8b42a34098b4e2d/html5/thumbnails/10.jpg)
Low power techniques
![Page 11: Low power vlsi design](https://reader036.fdocuments.us/reader036/viewer/2022082605/555e6d06d8b42a34098b4e2d/html5/thumbnails/11.jpg)
Low power Techniques
Clock Gating
To reducing dynamic power dissipation
works by taking the enable conditions attached to registers, and
uses them to gate the clocks
Power Gating
High Vt sleep transistors which cut off VDD from a circuit block when
the block is not switching
Also known as MTCMOS - Multi-Threshold CMOS
![Page 12: Low power vlsi design](https://reader036.fdocuments.us/reader036/viewer/2022082605/555e6d06d8b42a34098b4e2d/html5/thumbnails/12.jpg)
Calculation of Switching Activity
Input Pattern Dependence
Logic Function
Logic Style
Circuit Structure
![Page 13: Low power vlsi design](https://reader036.fdocuments.us/reader036/viewer/2022082605/555e6d06d8b42a34098b4e2d/html5/thumbnails/13.jpg)
Power Minimization Techniques
Reducing chip and package capacitance
Process development such as SOI with partially or fully depleted wells
Advanced interconnect substrates such as Multi-Chip Modules (MCM).
Scaling the supply voltage
Very effective
But often requires process technologies
Employing better design techniques
The investment to reduce power by design is relatively small
Using power management strategies
Various static and dynamic power management techniques
![Page 14: Low power vlsi design](https://reader036.fdocuments.us/reader036/viewer/2022082605/555e6d06d8b42a34098b4e2d/html5/thumbnails/14.jpg)
CAD Methodologies and Techniques
Low power VLSI design can be achieved at various levels of the design process
System Design
inactive hardware modules may be automatically turned off to save power
Behavioral Synthesis
The behavioral synthesis process consists of three steps:
Allocation
Assignment and scheduling
These steps determine how many instances of each resource are needed
Logic Synthesis
Physical Design
![Page 15: Low power vlsi design](https://reader036.fdocuments.us/reader036/viewer/2022082605/555e6d06d8b42a34098b4e2d/html5/thumbnails/15.jpg)
Conclusion
Low power VLSI is needed
Increasing of handheld devices
Increasing of complex device structure
Long battery life
Long device life
![Page 16: Low power vlsi design](https://reader036.fdocuments.us/reader036/viewer/2022082605/555e6d06d8b42a34098b4e2d/html5/thumbnails/16.jpg)