SiP Clock Alignment Using Interconnect Delay Compensation
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Solution Overview
Problem
System-in-package (SiP) devices face challenges in clock signal alignment across integrated circuits due to interconnect delays, which cause latency penalties in high-performance applications, especially when synchronous elements need to communicate across different clock domains.
Innovation Solution
The implementation of adaptive clock signal alignment across synchronous elements within SiP devices, where each expansion device compensates for interconnect delay by dynamically or statically determining the delay and adjusting its local clock signal to align with the host device's source clock signal, ensuring synchronous communication within a single clock domain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If clock domain crossing logic is used to synchronize signals across different clock domains in SiP devices, then communication between synchronous elements is enabled, but significant latency penalties occur
Solution Approach 1:
The patent segments the SiP package into multiple dies (host die and expansion die) with dedicated clock distribution networks on each die. By maintaining separate clock domains on each die and using synchronized clock signals, the system enables direct synchronous communication without requiring clock domain crossing logic, thereby eliminating the latency penalty while preserving communication capability.
2Adaptability or versatility
If multiple SiP devices are interconnected within a single package, then functionality and performance are enhanced, but clock signal alignment becomes difficult due to interconnect delays
Solution Approach 1:
The patent measures interconnect delays between the host die and expansion die during the manufacturing process and stores these delay values in configuration memory. This preliminary measurement and storage of delay information allows the system to pre-compensate for interconnect delays by adjusting clock signal phases, thereby achieving precise clock alignment without requiring complex real-time adjustment mechanisms.
Solution Approach 2:
The patent implements a feedback mechanism where the measured interconnect delay values are used to configure clock delay elements on the expansion die. This feedback loop ensures that clock signals are automatically adjusted to compensate for variations in interconnect delays, maintaining precise synchronization across multiple SiP devices despite manufacturing tolerances and environmental variations.
3Loss of time
If adaptive clock signal alignment is implemented to compensate for interconnect delay, then low-latency synchronous communication is achieved, but device complexity increases
Solution Approach 1:
The patent implements clock alignment only where necessary - specifically on the expansion die to compensate for delays from the host die. The host die uses a standard clock distribution network without additional alignment circuitry. This partial application of clock alignment technology achieves low-latency communication while minimizing the increase in device complexity by avoiding redundant alignment mechanisms.
Data Source
AI summary
A method embodiment of the present disclosure includes receiving a delay value associated with an interconnect delay that is measured across interconnect circuitry communicatively coupling a host semiconductor device with a semiconductor device. The method also includes delaying a local clock signal by an amount of delay indicated by the delay value to produce a delayed local clock signal. The method also includes receiving a delayed source clock signal, where the delayed source clock signal is received from the host semiconductor device via the interconnect circuitry. The method also includes outputting a master clock signal based on a comparison of the delayed source clock signal and the delayed local clock signal, where the master clock signal is utilized to generate one or more aligned clock signals on the semiconductor device that are aligned with a source clock signal generated on the host semiconductor device.