Multi-Die Circuit Scheduling for Power Supply Voltage Droop
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Solution Overview
Problem
Programmable integrated circuits like FPGAs face challenges in managing power delivery noise due to large supply current draws, leading to voltage droop issues, which are exacerbated by the complexity of power domains and cross-domain signals, making it difficult to mitigate noise effectively.
Innovation Solution
The solution involves operating groups of circuits in multiple integrated circuit dies sequentially or with interleaved delays to align high current events, reducing peak current draw and voltage droop by staggering the execution of operation threads across IC dies, thereby improving operational efficiency without increasing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If groups of circuits in multiple IC dies operate simultaneously, then productivity is improved, but power supply voltage droop increases
Solution Approach 1:
The patent implements periodic action by operating groups of circuits in different IC dies at staggered time intervals rather than simultaneously. Each die is activated in sequence with controlled delays, creating a periodic operation pattern that distributes current draw over time. This reduces peak current magnitude and prevents voltage droop while maintaining overall productivity through coordinated multi-die operation.
2Stability of the object's composition
If decoupling capacitance is increased to reduce voltage droop, then voltage stability is improved, but device area and cost increase
Solution Approach 1:
The patent applies preliminary action by proactively controlling the activation timing of circuits in different IC dies before voltage droop occurs. State machine circuits generate control signals that activate or deactivate specific dies in advance based on predicted current draw patterns. This preventive approach maintains voltage stability by avoiding peak current conditions rather than requiring large decoupling capacitance to correct voltage drops after they occur.
3Object-affected harmful factors
If more on-die decoupling capacitance is added, then power delivery noise is reduced, but manufacturing cost increases
Solution Approach 1:
The patent implements parameter changes by dynamically adjusting the operational state of different IC dies based on real-time power delivery conditions. State machine circuits monitor and control activation parameters, switching dies on or off to modulate current draw patterns. This dynamic parameter control reduces power delivery noise through temporal distribution of load rather than requiring increased decoupling capacitance, thereby avoiding additional manufacturing costs.
Data Source
AI summary
A circuit system includes a first integrated circuit die having a first group of circuits configured to perform a first set of operations. The circuit system also includes a second integrated circuit die having a second group of circuits configured to start performing a second set of operations with a delay after the first group of circuits starts performing the first set of operations to reduce power supply voltage droop. The operations performed by the first and second groups of circuits can be interleaved with a fixed or a variable delay. Logic circuits can be partitioned into the first and the second groups of circuits based on predicted switching activity of the logic circuits. Decoupling capacitors in integrated circuit dies can be coupled together to reduce droop in a supply voltage during a high current event.