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U. Glaeser

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FIGURE 2.36 BDD with complementary edges for function in Fig. 2.35.<br />

FIGURE 2.37 Correspondence among BDD, selector, and pass-transistor circuit.<br />

FIGURE 2.38 Example of PTL synthesis using BDD.<br />

© 2002 by CRC Press LLC<br />

A<br />

B B<br />

(a) Simplification with complementary edge<br />

Out1 = A + B (CD + CD)<br />

Out2 = A (CD + CD)<br />

0<br />

Out<br />

(a) Logic functions<br />

B<br />

Out1 Out2<br />

A<br />

CD + CD<br />

1 0<br />

(d) Sharing of two edges<br />

by Out1 and Out2<br />

Out<br />

A<br />

V dd<br />

1<br />

BDD<br />

A<br />

A<br />

A<br />

0<br />

A<br />

B<br />

complementary<br />

edge<br />

A<br />

A<br />

A<br />

0 1<br />

Out<br />

A<br />

B<br />

1<br />

(b) BDD with complementary edge<br />

Selector Pass-transistor circuit<br />

0 1<br />

Gnd V dd<br />

0 1<br />

0<br />

1 Gnd V dd<br />

Out1 Out2<br />

A<br />

A<br />

A=0 A=1 A=0<br />

B(CD + CD) 1 0 CD + CD<br />

(b) Shannon expansion for A<br />

Out1 Out2<br />

Out1 Out2<br />

In<br />

In<br />

pull-up pMOS<br />

D D<br />

1<br />

0<br />

(g) level restoration buffer (h) BDD after buffer insertion<br />

0<br />

B<br />

A =1<br />

A<br />

B<br />

A<br />

A<br />

A<br />

V dd<br />

Out1 Out2<br />

B 1 0 CD + CD<br />

B=0 B=1<br />

0 CD + CD<br />

(c) Shannon expansion for B<br />

Out1 Out2<br />

C<br />

Out1<br />

Out2<br />

D D<br />

0<br />

1<br />

(e) Shannon expansion for C (f) Final BDD<br />

B<br />

A<br />

A<br />

C<br />

1 0<br />

A<br />

C<br />

A<br />

B<br />

A<br />

A<br />

D<br />

Gnd<br />

A<br />

C<br />

A<br />

D<br />

D<br />

(i) Final pass-transistor circuit

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