On-Chip Clock Tree BIST for Arrival Time Variation Profiling

The patent applies preliminary action by pre-characterizing the clock tree during manufacturing to determine expected arrival times at different components. This pre-established timing information is stored and later used to compensate for process variations, allowing the system to account for timing differences before they affect circuit operation. The BIST circuit similarly performs preliminary measurements to establish baseline timing characteristics.

The patent utilizes parameter changes by measuring and compensating for variations in clock signal arrival times caused by process, voltage, and temperature changes. The system dynamically adjusts timing parameters based on measured variations, allowing the clock tree to maintain synchronization accuracy despite environmental and manufacturing variations that would otherwise cause performance errors.

The patent implements self-service through built-in self-test (BIST) circuits that are integrated within the chip itself. These BIST circuits can autonomously test clock tree performance without requiring external measurement equipment or additional bond pads. The system uses its own internal resources to characterize and verify timing behavior, eliminating the need for external testing infrastructure.

The patent merges the testing functionality with the existing clock tree infrastructure by integrating BIST circuits directly into the clock distribution network. This consolidation allows timing measurements to be performed using the same physical pathways that carry operational clock signals, eliminating the need for separate test access points or additional bond pads.

The patent applies universality by designing BIST circuits that can measure multiple parameters (arrival times, oscillation frequencies, timing variations) using a single integrated test infrastructure. The same BIST circuitry that characterizes clock tree timing also profiles on-chip variations across different operating conditions, allowing one system to serve multiple measurement purposes without proportionally increasing complexity.

The patent implements feedback mechanisms where BIST circuits continuously monitor clock signal characteristics and feed this information back to characterize PVT variations. The measured timing data is used to update the on-chip variation profile, which in turn informs timing compensation adjustments. This closed-loop approach enables accurate variation profiling while using efficient measurement techniques that don't require overly complex test equipment.