Decentralized Wake-Up for Dynamic Power Gating in ICs
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Solution Overview
Problem
Current power management techniques in integrated circuits (ICs) are inefficient in dynamically managing power consumption and waking up functional units, leading to suboptimal battery life in mobile devices due to lack of decentralized control and higher-level power gating strategies.
Innovation Solution
The implementation of a dynamic clock and power gating method with decentralized wakeups, where power-manageable functional units can request low power states and be awakened independently by logically adjacent units, and a power management unit performs clock and power gating at both individual and domain levels, ensuring efficient power management and reduced latency in transactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a functional unit enters a low power state to save energy, then power consumption is reduced, but the time to wake up and resume operation increases
Solution Approach 1:
The patent segments the power management system into multiple independent wake-up sources. Instead of a single centralized wake-up mechanism, multiple functional units can independently wake up other functional units through direct signaling. This segmentation allows for faster wake-up responses as the signaling path is shortened and parallel wake-up operations can occur simultaneously.
Solution Approach 2:
The patent implements preliminary action by maintaining idle state signaling capability even when functional units are in low power states. The ability to send and receive wake-up signals is preserved in advance, so when a wake-up event occurs, the functional unit can resume operation quickly without needing to fully power up the signaling infrastructure first.
2Device complexity
If centralized power management is used to control functional units, then power gating is simplified, but wake-up latency increases due to single-point control
Solution Approach 1:
The patent divides the centralized power management authority into distributed segments. Each functional unit has the capability to independently initiate wake-up events for other functional units. This segmentation eliminates the single-point control bottleneck while maintaining relatively simple individual unit designs, as each unit only needs basic wake-up signaling capability.
Solution Approach 2:
The patent enables self-service by allowing functional units to autonomously wake up other functional units without requiring centralized coordination. When a functional unit needs to communicate with another unit in low power state, it can directly initiate the wake-up sequence, making the system more responsive while keeping individual unit complexity low.
3Use of energy by moving object
If clock gating is applied to idle functional units, then dynamic power consumption is reduced, but the system responsiveness to wake-up events deteriorates
Solution Approach 1:
The patent applies local quality by differentiating the power management approach for different parts of the functional unit. Critical wake-up signaling paths maintain higher power states for faster response, while non-critical internal circuitry can be fully clock-gated. This selective application of clock gating preserves responsiveness where needed while maximizing power savings where possible.
Solution Approach 2:
The patent prepares the wake-up signaling infrastructure in advance by maintaining its operational readiness even when functional units are clock-gated. The signaling paths are pre-configured to allow rapid activation, so when a wake-up event occurs, the system can respond immediately without needing to initialize signaling paths during the wake-up process.
Data Source
AI summary
A method and apparatus for dynamic clock and power gating and decentralized wakeups is disclosed. In one embodiment, an integrated circuit (IC) includes power-manageable functional units and a power management unit. Each of the power manageable functional units is configured to convey a request to enter a low power state to the power management unit. The power management unit may respond by causing a requesting functional unit to enter the low power state. Should another functional unit initiate a request to communicate with a functional unit currently in the low power state, it may send a request to that functional unit. The receiving functional unit may respond to the request by exiting the low power state and resuming operation in the active state.