Circuit designing system
AssigneeNEC Corporation
InventorOsamu Yoshimura
Life of this patent
Estimating the term…
Abstract
A circuit designing system improves precision of fan out checking and further improves reasonableness of construction and consistency of derivation of a wiring capacity. Therefore, wiring lengths of respective wiring connected to respective output terminals of the circuit element of an objective circuit to be designed is predicted on the basis of a circuit design information and the wiring capacity is derived on the basis of the predicted wiring length. In the alternative, the wiring capacity is derived on the basis of the wiring length of respective wiring determined as a result of layout designing. The wiring capacity thus derived is used only for fan out checking, but also for logic synthesizing and logic simulation.
Claims10
A method for designing a circuit comprising the steps of:
- generating a circuit design information including a construction information and circuit connection information of an objective circuit to be designed;
- deriving wiring capacities of all wirings connected to output terminals of respective circuit elements in said circuit design information;
- checking whether the content of said circuit connection information is consistent with a preliminarily defined design rule;
- performing predetermined logic simulation on the basis of said wiring design information and the wiring capacity;
- performing layout designing for the objective circuit to be designed on the basis of said circuit design information;
- said design rule checking step including
- design rule storage step for storing a load driving performance of respective output terminals of circuit elements in said circuit design information;
- and
- fan out checking step for checking whether a load capacity derived by summing input capacities and said wiring capacities for all circuit elements connected to an output terminal with respect to the output terminals of respective circuit elements in said circuit design information, and whether the load capacity is within a given value range of the load driving performance in the corresponding output terminal.
A circuit designing system comprising:
- circuit design information generating means for generating a circuit design information including a construction information and circuit connection information of an objective circuit to be designed;
- wiring capacity calculating means for deriving wiring capacities of all wirings connected to output terminals of respective circuit elements in said circuit design information;
- design rule checking means for checking whether the content of said circuit connection information is consistent with a preliminarily defined design rule;
- logic simulation means for performing predetermined logic simulation on the basis of said circuit design information and the wiring capacity from said wiring capacity calculating means;
- layout designing means for performing layout designing for the objective circuit to be designed on the basis of said circuit design information;
- said circuit design information generating means including logic synthesizing means for performing predetermined logic synthesizing on the basis of the wiring capacity from said wiring capacity calculating means and generating predetermined information of said circuit designing information;
- said design rule checking means including
- design rule storage means for storing a load driving performance of respective output terminals of circuit elements in said circuit design information;
- and
- fan out checking means for checking whether a load capacity derived by summing input capacities and said wiring capacities for all circuit elements connected to an output terminal with respect to the output terminals of respective circuit elements in said circuit design information, and whether the load capacity is within a given value range of the load driving performance in the corresponding output terminal.
Dependencies are inferred from the claim text.