US Patent 10068048 Generating clock trees for a circuit design

The disclosure describes approaches for generating a clock tree for a circuit design. Initial clock trees are generated and elements are assigned to locations on an integrated circuit (IC). Each of the initial clock trees includes a clock root, a spine including the clock root, and branches connected to and extending from the spine. Each clock load is coupled to one of the branches. The clock tree further includes programmable delay circuits having initial delay values that are balanced. If the circuit design does not satisfy timing constraints, at least one clock root is moved from a respective first location to a respective second location.