Clock Tree Delay Validation Using Buffer Estimation

The patent segments the timing analysis process into two distinct phases: (1) buffer estimation and delay scaling performed before clock tree synthesis using simplified models, and (2) detailed path-based analysis performed after CTS on the synthesized clock tree. This segmentation allows the computationally intensive PBA to be focused only on the final synthesized design rather than being applied exhaustively to all intermediate design states, thereby improving computational speed while maintaining timing accuracy where needed.

The patent performs preliminary buffer estimation and delay scaling analysis before clock tree synthesis to predict timing characteristics and guide the CTS process. By performing this preliminary action, the system can optimize buffer placement and sizing during synthesis based on pre-calculated delay models, reducing the need for multiple iterative PBA passes and thereby improving overall computational efficiency while maintaining timing accuracy.

The patent performs AOCV analysis before clock tree synthesis to establish initial timing constraints and buffer requirements. By performing this preliminary action, the system can incorporate timing validation insights into the CTS process itself, allowing buffers to be placed and sized to meet timing requirements without adding excessive margin. This preliminary AOCV analysis reduces excess pessimism by providing accurate timing guidance before the clock tree structure is finalized.

The patent implements a feedback loop where AOCV analysis results from pre-CTS timing validation are fed back into the clock tree synthesis process to optimize buffer placement and sizing. This feedback mechanism allows the system to adjust timing constraints and buffer configurations based on actual AOCV measurements, reducing excess pessimism by ensuring that timing margins are based on real variation data rather than conservative estimates. The feedback loop continues through post-CTS AOCV analysis to verify timing closure.

The patent performs preliminary buffer estimation, delay scaling, and AOCV analysis before clock tree synthesis to establish timing constraints and optimization targets. By performing these actions preliminarily, the system can guide the CTS process to create an optimized clock tree structure from the outset, reducing the need for iterative design changes after synthesis. This preliminary optimization maintains timing validation accuracy while significantly reducing design cycle time by locking in optimal buffer placements before the design freezes.

The patent segments the design optimization process into pre-CTS and post-CTS phases, with each phase having specific optimization objectives. The pre-CTS phase focuses on buffer estimation and delay scaling to guide synthesis, while the post-CTS phase performs detailed timing validation and fine-tuning. This segmentation allows major optimization decisions to be made early when design changes are still flexible, reducing the need for time-consuming iterative changes later in the design cycle while maintaining accurate timing validation.