One embodiment of the present invention provides a system which performs a constrained optimization of circuit parameters. During operation, the system selects two circuit parameters associated with a circuit path, wherein the optimization is to be performed on the first circuit parameter while a limitation on second circuit parameter functions as a constraint on the optimization of the first circuit parameter. Next, the system generates objective functions which model the first circuit parameter and the second circuit parameter in terms of logical effort. The system then uses the objective functions to generate a constraint expression, wherein the constraint expression mathematically relates the optimization of the first circuit parameter to the constraint on the second circuit parameter. Next, the system computes a trade-off curve using the constraint expression. The system then computes transistor sizes for the circuit path based on a selected point from the trade-off curve.