Patent ID: 6820242
Filing Date: 2004-11-16
Classification: G06F,H03K

Abstract:
The method of synthesizing in a computer system a logic circuit on the basis of a Boolean function which provides a relationship between a group of input variables representing a corresponding group of input signals to a logic circuit to be synthesized and at least one output variable representing at least one corresponding output signal from the logic circuit, comprising the steps of:(a) creating a binary decision diagram from the Boolean function; (b) replacing nodes of the binary decision diagram with pass transistor selector circuits each having two-inputs, one-output and one-control input to produce a pass transistor logic circuit; (c) replacing a pass transistor selector circuit in which either one of the two inputs is fixed to a logical constant â€œ1â€ or â€œ0â€  with a CMOS gate operating in a logically equivalent logic to produce a logic circuit including a combination of pass transistor selector circuits and CMOS circuits, and (d) outputting the logic circuit including a combination of pass transistor selector circuits and CMOS circuits obtained by the above steps as a logic circuit for the Boolean function, further comprising the steps of: (e) calculating values of predetermined circuit characteristics of the pass transistor logic circuit obtained in step(b) and the logic circuit obtained in step (c); wherein step (d) is executed when the values of circuit characteristics of the logic circuit obtained in step (c) are better than the values of circuit characteristics of the logic circuit obtained in step (b).