Sequential Power Switch Wakeup With Adaptive Delay Chains
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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, and accelerating the wakeup process by adjusting delay elements based on voltage thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If power switches are activated simultaneously to enable a power gated block, then the wakeup speed is maximized, but excessive current inrush and power supply noise occur
Solution Approach 1:
The power switch activation process is segmented into multiple sequential stages rather than a single simultaneous event. The enable signal is distributed through delay chains that activate different portions of the power gated block at different times, dividing the total current inrush into manageable segments that occur sequentially rather than all at once.
Solution Approach 2:
Delay chains are预先 configured to control the timing of power switch activation. These delay elements prepare and sequence the enable signal distribution before actual power switch activation occurs, ensuring that switches are turned on in a predetermined sequence that limits current inrush while maintaining acceptable wakeup speed.
2Object-generated harmful factors
If power switches are activated sequentially to reduce current inrush and noise, then power supply noise is reduced, but the wakeup time increases
Solution Approach 1:
The delay chain configuration is made dynamic and adjustable rather than fixed. Different delay values can be selected based on operating conditions such as voltage level, temperature, and process variations. This allows the system to optimize the balance between wakeup speed and noise reduction by adjusting the sequencing timing in real-time according to environmental conditions.
Solution Approach 2:
The delay elements' timing parameters are changed based on voltage thresholds and operating conditions. As voltage increases or operating conditions change, the delay values are adjusted to maintain optimal wakeup performance. This parameter adjustment ensures that the sequential activation process remains efficient across different operating scenarios without excessive wakeup time.
3Object-generated harmful factors
If delay elements provide fixed delay to sequentially activate power switches, then current inrush is controlled, but wakeup speed is reduced due to excessive delay
Solution Approach 1:
The delay chain system transitions from fixed delay to dynamic, adjustable delay. Multiple delay elements can be selectively enabled or configured based on the number of power switches and operating conditions. This dynamic configuration allows the system to use minimal necessary delay to control current inrush while avoiding excessive delay that would slow wakeup.
Solution Approach 2:
The delay chain is segmented into multiple adjustable stages rather than a single fixed delay. This segmentation allows fine-grained control over the activation sequence, enabling the system to optimize the balance between current inrush control and wakeup speed by adjusting individual stage delays rather than applying a uniform fixed delay across all switches.
4Productivity
If power switches are activated faster to reduce wakeup time, then productivity is improved, but current inrush and noise exceed specifications
Solution Approach 1:
The delay chain parameters are dynamically adjusted based on voltage thresholds and operating conditions to optimize wakeup efficiency. As voltage increases or conditions change, the delay values are modified to allow faster activation while still maintaining compliance with current inrush and noise specifications. This parameter adaptation enables the system to achieve maximum productivity within specified limits.
Solution Approach 2:
The system incorporates feedback mechanisms that monitor voltage levels, temperature, and other operating parameters to dynamically adjust the delay chain configuration. This feedback allows the system to automatically optimize the power switch activation sequence to achieve fastest possible wakeup while ensuring that current inrush and noise remain within specification limits under all operating conditions.
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.