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FIGURE 2.52 PCCL synthesis flow.<br />

FIGURE 2.53 Example of PCCL synthesis.<br />

© 2002 by CRC Press LLC<br />

Logic description<br />

BDD construction<br />

Multilevel BDD or<br />

decomposed BDD<br />

Pass-transistor selector mapping<br />

CMOS circuits remapping<br />

according to figure 20.25 (b)<br />

Cost (area/delay/power) estimation<br />

α β γ<br />

Cost = area delay power<br />

A<br />

B<br />

C<br />

D<br />

E<br />

G<br />

H<br />

F<br />

I<br />

Pass-transistor/CMOS<br />

selection by cost<br />

PCCL<br />

(a) Synthesis flow<br />

Out1 = A B + A C + (D + (G + E) (E + H)) (D + I F)<br />

Out2 = B + (D + (G + E) (E + H)) (D + I F)<br />

B<br />

A<br />

Out1<br />

X<br />

C<br />

0 1<br />

V dd<br />

B<br />

(3)<br />

(a) Logic function<br />

(b) Multi-level BDD<br />

V<br />

dd A<br />

(1)<br />

Out1 B<br />

C<br />

D<br />

E<br />

(2)<br />

(d) Area-oriented PCCL (cost = area)<br />

0<br />

G<br />

E<br />

H<br />

D<br />

I<br />

F<br />

G<br />

H<br />

F<br />

Out2<br />

I<br />

1<br />

0<br />

V dd<br />

B<br />

Pass-transistor circuit CMOS circuit<br />

Out<br />

V<br />

dd<br />

Out<br />

A<br />

A<br />

B<br />

B<br />

Out<br />

V<br />

dd<br />

A<br />

Out2<br />

Y<br />

A<br />

A<br />

1<br />

(3)<br />

B<br />

Out<br />

B<br />

Out<br />

B<br />

B<br />

B<br />

A<br />

A<br />

A<br />

B<br />

(b) Candidates for remapping<br />

PCCL<br />

CMOS<br />

Area-oriented Delay-oriented Power-oriented<br />

Area ( m 1380 (1.00) 906 (0.66) 949 (0.69) 1164 (0.84)<br />

Delay (ns) 1.72 (1.00) 1.61 (0.94) 1.39 (0.81) 1.55 (0.90)<br />

Power (µW/MHz) 340 (1.00) 147 (0.43) 179 (0.53) 137 (0.40)<br />

2) µ<br />

(g) Comparison of PCCLs with CMOS<br />

B<br />

A<br />

B<br />

C<br />

D<br />

E<br />

G<br />

H<br />

F<br />

I<br />

(c) Pass-transistor circuit after mapping<br />

V<br />

dd<br />

A<br />

Out1<br />

B<br />

C<br />

(1)<br />

D<br />

E<br />

V<br />

dd<br />

F<br />

Out2<br />

I<br />

(2)<br />

V dd<br />

V dd<br />

Out<br />

Out<br />

Out<br />

(e) Delay-oriented PCCL (cost = delay) (f) Power-oriented PCCL (cost = power)<br />

G<br />

H<br />

B<br />

B<br />

Out1<br />

Out2<br />

Out1<br />

Out2

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