Logic Design for Array-Based Circuits

Copyright © 1996, 2001, 2002, 2008, 2016 Donnamaie E. White, WhitePubs Enterprises, Inc.

• Table of Contents
  
• Preface
  
• Overview
  
• Chapter 1 Introduction
  
• Chapter 2 Structured Design Methodology
• Chapter 3 Sizing the Design
• Chapter 3 Appendix = Case Study in Sizing a Design
• Chapter 4 Design Optimization
• Chapter 5 Timing Analysis for Arrays
• Chapter 6 External Set-up and Hold Times
• Chapter 7 Power Considerations
• Case Study: DC Power Computation
  • Steps Required to Compute DC Power - Example Array Series
  • Build the Macro Occurence Table
  • Find the Tital Interface Macro Current
  • Computer the Worst-Case Interface Current
  • Compute the Total Typical Internal Macro Current
  • Compute the Worst-Case Internal Current
  • Compute the Total Typical Overhead Current
  • Compute the Worst-Case Overhead Current
  • Sum the ICC and IEE Currents
  • Multiply by Worst-Case Voltage
  • Determine ECL Static Power PEO
  • ECL Output Termination Current
  • Sum the Result - Total DC Power
  • Exercises
• Case Study: AC Power Computation
  • Build the Macro Occurrence Table
  • Find the Number of Darlington Outputs
  • Compute AC Power for all ECL Darlington Output Macros
  • Find the Number of ECL Inputs
  • Compute AM Power for all ECL Input Macros
  • Find the Number of Internal Macros
  • Compute AC Power for all Internal Macros
  • Sum All Components of AC Power
  • Total Power Dissipation
  • Exercises
• Chapter 8 Simulation
• Case Study: Simulation
• Chapter 9 Faults and Fault Detection
• Chapter 10 Design Submission
• ASIC Glossary
  • Glossary A-D
  • Glossary E-K
  • Glossary L-R
  • Glossary S-Z
  • Symbols

Power Considerations

Last Edit July 22, 2001

Step 7: Compute the Worst-Case Overhead Current

Multiply both the IEE and ICC overhead currents by the worst-case current multiplier for the overhead current (WCCM3) to obtain the worst-case overhead currents

IoverheadCCwc = WCCM3 * IoverheadCC
IoverheadEEwc = WCCM3 * IoverheadEE

Step 8: Sum the ICC and IEE Currents

Sum the internal macro, interface macro, and overhead worst-case currents, keeping ICC and IEE separate to find the total IEE and ICC worst-case currents

ICCwc = SUM IinternalCCwc + IinterfaceCCwc + IoverheadCCwc
IEEwc = SUM IinternalEEwc + IinterfaceEEwc + IoverheadEEwc

Step 9: Multiply by the Worst-Case Voltage

The worst-case voltage is dependent on whether the circuit is commercial or military and the specified allowed power supply variations. The array data sheet carries this information. The typical variation is shown below. For commercial circuits, with a -5.2V or a +5V supply, the voltage variation is usually ±5%. For commercial circuits using VEE = -4.5V, the variation is ±7%

For military circuits, the voltage variation is usually ±10%. Note: The worst-case voltage for the -4.5V supply as listed on the Q20000 data sheet, where -4.5V supply varies ±7%. The worst-case voltage is taken as -4.8V for military or commercial circuits

Table 7-14 Example Worst-Case Voltages

Multiply the worst-case DC current by the appropriate worst-case voltage:

PEEDC = IEEwc * VEEwc
PCCDC = ICCwc * VCCwc

This product is the worst-case DC power due to the macros on the array.

Copyright © 1996, 2001, 2002, 2008, 2016 Donnamaie E. White , WhitePubs Enterprises, Inc.
For problems or questions on these pages, contact donnamaie@-no-spam-sbcglobal.net