Low Power, Variable Width Tri-Multiplier for VIRAM

Cheol-Woong Lee
&
Norman Walker


5/11/98



Abstract

Modern times have merged design methodologies behind general purpose and DSP processors. Merging of DRAM and combinational logic has also brought forth the reintroduction of vector processors that satisfy the high bandwidth provided by on-chip memory. Specific to the IRAM case, vector processors must interact smoothly with three given data types. This requires the multiplier units to perform fixed point (DSP) multiplication, while keeping the ability to perform regular floating point and integer functionality. To satisfy these conditions, our research focuses on combination of three multipliers into a single pipelined "variable width tri-multiplier" while adhering to strict power requirements. Current technology (0.35 uM Process, Double Pass Transitor Logic, 2.5V operation) allows for the Worst Case 563.58 mW multiplier (64 Bit Floating Point) with 1.60 mM 2 area, while future technology (0.35 uM Process, Double Pass Transitor Logic, 1.0V operation) might allow for 0.2V Threshold Voltage, reducing power to only the Worst Case 116.21 mW (64 Bit Floating Point).


  1. Introduction
  2. Discussion of Architecture
    1. Design Consideration
    2. Initial Architecture
    3. Sail Boat Allocation : Natural Ratio
    4. Sail Boat Allocation : Square Ratio
    5. Conversion from Signed to Unsigned 16 bit multiplication
    6. Conversion from Unsigned to Signed 16/32/64 bit multiplication
    7. Low Power Architecture
  3. Power Performance Analysis
    1. Power Performance Analysis I : Natural Ratio vs. Square Ratio
    2. Power Performance Analysis II : Natural Ratio vs. Enhanced Natural Ratio
    3. Power Performance Analysis III : Low Power Design Technology
  4. Cycle Time Analysis
    1. Cycle Time Analysis I : Natural Ratio & Square Ratio
    2. Cycle Time Analysis II : Natural Ratio vs. Enhanced Natural Ratio
    3. Cycle Time Analysis III : Low Power Design Technology
  5. Area Analysis
    1. Area Analysis I : Natural Ratio vs. Square Ratio
    2. Area Analysis II : Natural Ratio vs. Enhanced Natural Ratio
    3. Area Analysis III : Low Power Design Technology
  6. Power/CycleTime/Area Summary
  7. Floor Plan
  8. Conclusions
  9. References