Coast Mode Power Management for IC Leakage Reduction
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Solution Overview
Problem
As semiconductor fabrication technologies advance, leakage currents in integrated circuits increase, leading to inefficiencies in power management, particularly with traditional clock gating and power gating methods, which fail to effectively reduce energy consumption and heat generation.
Innovation Solution
Implementing a 'coast mode' where the power management unit temporarily disables the power supply voltage to integrated circuits, allowing them to operate on stored energy in capacitance, thereby reducing energy loss and enhancing energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If clock gating is used to reduce dynamic power consumption, then dynamic power consumption is reduced, but leakage current loss increases due to continued circuit operation
Solution Approach 1:
The patent implements dynamic power management by transitioning circuits between active and coast modes based on operational requirements. The coast mode dynamically reduces power supply voltage while maintaining circuit functionality, adapting power consumption to actual workload demands rather than using static clock gating approaches.
Solution Approach 2:
The patent changes the power supply voltage parameter from full voltage to reduced voltage during coast mode operation. This parameter change allows the circuit to operate with lower power consumption while maintaining functionality, effectively addressing both dynamic power consumption and leakage current loss by operating in a voltage-reduced state.
2Loss of energy
If power gating is used to reduce leakage current loss, then leakage current loss is reduced, but circuit activation time increases and reset requirements are introduced
Solution Approach 1:
The coast mode provides a dynamic intermediate state between full power operation and complete power gating. Instead of abruptly gating power and requiring reset sequences, the circuit transitions to a reduced voltage coast mode that maintains operational state while reducing leakage, enabling faster reactivation without reset requirements.
Solution Approach 2:
The patent maintains capacitor charge during coast mode as a form of energy cushioning. This stored energy allows the circuit to continue operating during the transition period without requiring immediate power restoration or reset sequences, effectively cushioning against the activation time penalty associated with power gating.
3Reliability
If power supply voltage is continuously maintained, then circuit operation is uninterrupted, but energy consumption increases due to PMU losses
Solution Approach 1:
The patent implements periodic power management by alternating between full power mode and coast mode based on circuit activity requirements. During coast mode, the power supply voltage is reduced periodically rather than continuously maintained, reducing PMU energy losses while maintaining circuit operation through stored capacitor energy.
Solution Approach 2:
The circuit serves itself during coast mode by operating on energy stored in internal and external capacitors without requiring active PMU power regulation. The stored capacitor energy self-sustains circuit operation during the coast interval, eliminating PMU losses while maintaining functionality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces overall energy consumption by minimizing energy loss in the power management unit and allows for efficient use of stored energy during coast intervals, improving power management in integrated circuits.
Implementation Method 1
The integrated circuit may continue to operate, consuming the energy stored in capacitance in and/or around the integrated circuit.
Data Source
AI summary
In an embodiment, a system may support a “coast mode” in which the power management unit (PMU) that supplies the supply voltage to an integrated circuit is disabled temporarily for certain modes of the integrated circuit. The integrated circuit may continue to operate, consuming the energy stored in capacitance in and/or around the integrated circuit. When coast mode is initiated, a time interval for coasting may be determined. When the time interval expires, the PMU may re-enable the power supply voltage.