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Magic Blue Smoke
  • About

    Magic Blue Smoke is a blog dedicated to discussing the challenges of low power ASIC Design

    I have worked in the VLSI industry for 14 years as a digital IC designer. My recent work has been focused on low-power challenges associated with multi-voltage/
    multi-supply designs. The goal of this blog is to open a free exchange of ideas with regards to low power. Please participate!

    - Godwin Maben

Archive for the 'implementation' Category

Structural Errors

Posted by Godwin Maben on 20th November 2008

Today let’s look at the various structural errors or bugs that can be really destructive for any MV design. Structural error is a bug, which is caused either by, the way RTL is written or implementation tools interpreting the power intent incorrectly. These can be further classified as structural errors leading to electrical violations or structural errors leading to pure functional failures. Given below are some of them

(a) Placement of Buffers in wrong location
(b) Level Shifter Missing
(c) Isolation cell missing
(d) Wrong Isolation Polarity
(e) Using LS+ISO instead of Enable Level Shifter
(f) Normal Buffer instead of AON buffer being used
(g) AON buffers with single rail placed in non-power able region
(h) Placement of Special Cells in wrong location
(i) Connection of Switch cells
(j) Connection of all dual rail cells not aligned with proper power strategy
(k) Power/Ground Net Connectivity for Islands
(l) Redundantly Retained and Not Retained.
(n) Retention Reach ability
(o) Retention Flops wrong polarity
(p) Unsafe Voltages
(q) Incorrect Clamp Values
(r) Wrong Tie-Hi and Tie-Lo Connections
(s) Isolation Enable reaching Data pin of Isolation cell
(t) Rail Order Violations for islands

Posted in implementation, low power general | 1 Comment »

Low Power Techniques in use Today

Posted by Godwin Maben on 1st April 2007

Lets take a look at various low power techniques in use today.I would classify the various low power techniques into 2 categories

(a)Structural Techniques

  • Voltage Islands
  • Multi-threshold devices
  • Multi-oxide devices
  • Minimize capacitance by custom design
  • Power efficient circuits
  • Parallelism in micro-architecture
  • (b)Traditional Techniques

  • Clock gating
  • Power gating
  • Variable frequency
  • Variable voltage supply
  • Variable device threshold
  • Which one of the above techniques are aimed at reducing Dynamic Power and Leakage Power

    Dynamic Power Reduction

  • Clock Gating
  • Power efficient circuits
  • Variable frequency
  • Variable voltage supply
  • Leakage Power Reduction

  • Minimize usage of Low Vt Cells
  • Power Gating
  • Back Biasing
  • Reducing Dynamic Power
  • Reduce Oxide Thickness
  • Use FINFET’s
  • Posted in implementation | 10 Comments »