Power Performance Analysis II : Natural Ratio vs. Enhanced Natural Ratio

Basic Assumption

(1) Technology : 0.35um CMOS process
(2) Operating Voltage : 2.5 V
(3) Operating Temperature : 25 C
(4) Circuit : Dual-Rail Domino Logic
(5) 16 bit Multiplier : Wallace Tree + 32bit CLA Adder
(6) Architectural Change and No Change for Circuit Technology


Power Estimation Method

(1) The power calculation is based on the paper, Carl Lemonds, "A High Throughput 16 by 16 Bit Multiplier for DSP Cores", IEEE International Symposium on Circuits and Systems, 1996. p479.

(2) 32bit Wallace Tree

3to2 Wallace Tree Compressor has 30 transistors.
2to2 Wallace Tree Compressor has 14 transistors.
5to3 Wallace Tree Compressor has 52 transistors.

32 bit Wallace Tree has 28 3to2 Wallace Tree Compressors,
8 2to2 Wallace Tree Compressors,
102 5to3 Wallace Tree Compressors.
Total number of transistors is 28*30 + 8*14 + 102*52 = 6256.
Power : 6256 * 9.216 uW @200MHz = 57.655 mW

(3) 48bit Wallace Tree (Double)

3to2 Wallace Tree Compressor has 30 transistors.
2to2 Wallace Tree Compressor has 14 transistors.
5to3 Wallace Tree Compressor has 52 transistors.

32 bit Wallace Tree has 90 3to2 Wallace Tree Compressors,
45 2to2 Wallace Tree Compressors,
51 5to3 Wallace Tree Compressors.
Total number of transistors is 90*30 + 45*14 + 51*52 = 5982.
Power : 5982 * 9.216 uW @200MHz = 55.130 mW

(4) Power Table 4 : Natural Ratio vs. Enhanced Natural Ratio

Natural
Ratio
mult16

Natural
Ratio
mult32

Natural
Ratio
mult64

Enhanced
Natural
Ratio
mult16

Enhanced
Natural
Ratio
mult32

Enhanced
Natural
Ratio
mult64

Sail Boat Allocation

64.52 mW

106.58 mW

190.68 mW

64.52 mW

106.58 mW

190.68 mW

16 bit Multiplier

640.00 mW

1280.00 mW

2560.00 mW

N/A

N/A

N/A

32bit Wallace Tree

N/A

N/A

N/A

230.62 mW

461.24 mW

922.48 mW

32bit CLA Adder

N/A

N/A

N/A

126.71 mW

N/A

N/A

48 bit Wallace Tree

N/A

54.44 mW

108.88 mW

N/A

110.26 mW

220.52 mW

48 bit CLA Adder

N/A

109.66 mW

219.32 mW

N/A

N/A

N/A

64 bit CLA Adder

N/A

N/A

N/A

N/A

161.85 mW

N/A

32 bit FP Converter

N/A

29.56 mW

N/A

N/A

29.56 mW

N/A

96 bit Wallace Tree

N/A

N/A

53.95 mW

N/A

N/A

110.26 mW

96 bit CLA Adder

N/A

N/A

140.08 mW

N/A

N/A

N/A

128 bit CLA Adder

N/A

N/A

N/A

N/A

N/A

206.74 mW

96 bit FP Converter

N/A

N/A

37.77 mW

N/A

N/A

37.77 mW

Output Registers (FIX/INT)

42.05 mW

16.82 mW

16.82 mW

42.05 mW

16.82 mW

16.82 mW

Output Registers (FP)

N/A

8.41 mW

8.41 mW

N/A

8.41 mW

8.41 mW

Total Power (FIX/INT)

746.57 mW

1567.50 mW

3289.73 mW

421.85 mW

856.75 mW

1667.50 mW

Total Power (FP)

N/A

1588.65 mW

3319.09 mW

N/A

877.90 mW

1696.86 mW

[ TABLE 4 ]