4. Introduction
With rapid developments in field of signal processing, control systems and other computer applications,
arithmetic circuits mainly multipliers are becoming very important.
To design high performance handheld gadgets, circuit designs must be optimized for area, power and
timing. All the three tenets of VLSI design: area, power and timing must be given attention during
design.
Here the focus is on designing booth multipliers with different adder architectures and their ASIC
implementation.
Booth multipliers are designed using CLA, RCA and CSA adders. Area, power and timing analysis of
different designs
5. Definition
• -Consider an integer y whose 2’s
complement representation is xn-1 xn-2
…. x0 and define
• y0 = -x0,
• y1 = -x1 + x0,
• y2 = -x2 + x1,
• .. .
• .. .
• yn-1 = -xn-1 + xn-2;
• Then by multiplying the first equation by
20, the second by 21, the third one by 22,
and so on, and adding up the n equations,
the following relation is obtained:
•
• The vector (yn-1 yn-2 …. y0) whose
components yi belong to {-1, 0, 1} is the
Booth-1 representation of x and
•
7. Arrangement of CLA in
Booth Multiplier
• The worst-case delay is of a two-level CLA is
given by the expression
8. Advantages
For faster computation speed, the longer operand should be
taken as input-A, while for less area utilization and fewer
operating units, the shorter operand should be taken as input-
A.
The configurability of the IVS multiplier avoids unnecessary
computing cycles and dynamic energy once the operands are
not full-64 bits, which can significantly reduce the glitching
activity, but it requires additional control circuitry to generate
the gated clocks for various registers in the implementation.
Reduces the power consumption at comparable speed
9. Disadvantages
• it does not provide details of the adder
logic used, which plays a significant role in
the multiplier delay, area and the power
consumption