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 4: Compute the Total Typical Internal Macro Current

The macro current for individual internal macros is multiplied by the number of occurrences to determine the total for the use of that macro in the circuit. Change the labels if power has been specified

Compute the total current used by all occurrences of each internal macro and sum these totals to find:

IinternalEE = SUM INTERNAL MACROS IEE CURRENT
IinternalCC = SUM INTERNAL MACROS ICC CURRENT

Unless the circuit uses a single-power supply these two sums must be kept separate

Step 5: Compute the Worst-Case Internal Current

Multiply both sums by the worst-case current multiplier for the internal macros (WCCM2) to obtain the worst-case current due to interface macros

IinternalCCwc = WCCM2 * IinternalCC
IinternalEEwc = WCCM2 * IinternalEE

Step 6: Compute the Total Typical Overhead Current

Compute the total overhead current used by the circuit

IoverheadEE = Table entry for array and I/O mode
IoverheadCC = Table entry for array and I/O mode

Unless the circuit uses a single-power supply these two terms must be kept separate.

The vendor may specify a computation based on number of inputs or outputs of a given type. AMCC specifies a typical overhead current by array, by I/O mode (ECL-TTL or mixed) and power supply

Note: The DECL and the mixed ECL/TTL dual supply arrays dissipate the same overhead current. In the case of the DECL circuit, some of the ma-cros that require the use of two power supplies will dissipate an ICC current component

Table 7-13 Q20000 Series Example Typical Overhead Currents

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