Magic Blue Smoke

Archive for 2007

 

UPF Overview Part I

UPF is a way to represent the Power Intent of a design. It directs all the tools in the flow to interpret the Power Intent in the same way. Before we jump into the details of UPF, let’s try to understand what we mean by Power Intent. Typically for any design implementing any of the […]

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Posted in Architecture | Comments Off on UPF Overview Part I

 

UPF Introduction

So far my posts have dealt with various power reduction techniques used by designers as well as some of the challenges faced using these techniques in the design flow. Most of the complexity in using these techniques comes from the fact that we need to interpret virtual logical/physical power structures, since most of them are […]

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Posted in Power Format | 4 Comments »

 

IR Drop Management Cont’d

Could not write much for last few weeks and would like to complete the IR-Drop series with few good articles today. These days I am hearing lot of questions/concerns about UPF,its usage and how the whole design flow is going to look like with UPF. Planning to start a UPF tutorial running for 4-5 posts […]

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Posted in low power general | 4 Comments »

 

Managing IR Drop Continued

I apologize for not writing as often as I would like, Was quite busy with multiple design flow related activities. Bear with my busy schedule for the next few weeks. Important points to consider when determining your methodology for power rail analysis include: (a) Use static IR analysis to generate robust power rails.(b) Use dynamic […]

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Posted in low power general | 1 Comment »

 

Managing IR Drop Issues in General

Most common issue faced in any Low Power Design is how can we minimize noise coupling between different rails and between cells in the same power domain. I am planning on discussing these in my next 2 posts. Power and Ground Noise can degrade timing and can lead to functional failures. Most commonly used method […]

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DVFS Impacts Timing Closure

I was in discussion with a designer other day on “Impact on performance of the design if the voltage range is not choosen correctly”, today I am going elaborate a bit on this topic. While designing the system with DVFS techniques, we need to look at the impact of temperature inversion on the performance of […]

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Posted in Architecture | 2 Comments »

 

Library Modelling for Isolation Cells

I Forgot to add the syntax of Modelling Isolation cells. Thanks Sampath for reminding me on this. Here is one way to model ISOLATION cells cell (isolation_cell) { cell_leakage_power : 2.382 ; pg_pin(VSS) { voltage_name : VSS; pg_type : primary_ground; } pg_pin(VDD) { voltage_name : VDD; pg_type : primary_power; } pin(data_in) { direction : input; […]

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Posted in Library Modelling | 1 Comment »

 

Voltage/Frequency Scaling Mechanisms

I was in Boston last week attending SNUG and got a chance to interact with many designers and one of the key concerns raised were in understanding the Voltage scaling approach . Planning to take a quick tour on this topic in my next few posts There are various voltage scaling approaches that are in use today […]

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Posted in Architecture | 8 Comments »

 

How to model Special Cells in libraries?

I have been post-poning explaining about the library requirements for quite sometime. Today let me explain little bit on library modelling of special cells such as (1) Level Shifter (2) Isolation Cell (3) Retention flop (4) Always On Cell (5) Switch Most important information to note here is, these special cells may have multiple power […]

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Posted in Library Modelling | 8 Comments »

 

Simulating Retention behaviour using UPF

Last week, we saw on how to simulate retention flops using $functions as well as using adhoc methods to simulate similar behaviour. We have been hearing a lot about power standards helping us in solving this problem. Here is how UPF can help us in simulating this behaviour set_retention gated_retention -domain IGATED_DOMAIN -retention_power_net VDD -retention_ground_net […]

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Posted in Architecture | Comments Off on Simulating Retention behaviour using UPF