Power Switch Acceleration for Fast Wakeup With Low Inrush Noise
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Solution Overview
Problem
Power gating in integrated circuits leads to noise on power supply connections due to changes in current flow, affecting operation and increasing delay in enabling power gated blocks, especially with variations in semiconductor fabrication, voltage, and temperature.
Innovation Solution
A power switch acceleration scheme that uses a virtual voltage node and delay chains to sequentially activate power switches, reducing current inrush and noise by increasing the rate of power switch activation as the voltage on the virtual node rises, allowing for faster wakeup while maintaining current and noise specifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If power switches are activated simultaneously during wakeup, then the wakeup speed is maximized, but excessive current inrush and power supply noise occur
Solution Approach 1:
The patent divides the power switch activation process into multiple segments by grouping power switches and activating them in sequential stages. Delay chains are used to create time-staggered activation groups, where each group activates after a predetermined delay period. This segmentation allows the system to achieve fast wakeup while controlling current inrush by limiting the number of switches activated simultaneously in each stage.
Solution Approach 2:
The patent implements dynamic activation rates by adjusting the delay periods between successive activation groups based on operating conditions. The delay chains can be configured with different delay values to optimize the activation sequence, allowing the system to adapt the wakeup profile dynamically. This dynamic approach enables faster activation when conditions permit while maintaining noise control when necessary.
2Object-generated harmful factors
If power switches are activated sequentially with fixed delays, then current inrush and noise are controlled, but wakeup speed decreases
Solution Approach 1:
The patent applies partial action by activating only a subset of power switches in each stage rather than all switches simultaneously or all switches with uniform delays. The delay chains enable different activation rates for different groups, allowing the system to use faster activation rates for non-critical blocks while maintaining controlled activation for noise-sensitive blocks. This partial differentiation optimizes overall wakeup speed while maintaining noise control.
3Speed
If the activation rate is increased as voltage rises, then wakeup speed improves while current and noise specifications are maintained, but complex control logic is required
Solution Approach 1:
The patent implements preliminary action by pre-configuring delay chains with predetermined delay periods before the wakeup event occurs. The delay elements are designed and configured during system initialization or design phase, establishing the activation sequence in advance. When wakeup is triggered, the pre-configured delay chains automatically execute the optimized activation sequence without requiring real-time control decisions, thereby achieving fast adaptive wakeup while minimizing runtime control complexity.
Data Source
AI summary
A method an apparatus for a power switch acceleration scheme during wakeup is disclosed. In one embodiment, an integrated circuit includes at least one power gated circuit block. The power gated circuit block includes a virtual voltage node from which a voltage is provided to the circuitry of the block when active. Power switches are coupled between the virtual voltage node and a corresponding global voltage node. When the power gated circuit block is powered on, power switches are activated sequentially. The rate at which power switches are activated is increased as the voltage on the virtual voltage node increases. Sequentially activating the power switches may prevent an excess of current inrush into the power gated circuit block. The increase in the rate at which power switches are activated when the voltage on the virtual voltage node is at least at a certain level may allow for a faster wakeup.