Dynamic Memory Rail Voltage Adjustment via Sensor Cell Feedback
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Solution Overview
Problem
In large integrated circuits, dynamically adjusting supply voltages across multiple supply domains with different configurations and devices is challenging due to varying power attributes and requirements, leading to inefficiencies in power consumption and potential data loss from memory bitcells.
Innovation Solution
The implementation of sensor cells with bitcell replicas and a power management circuit that dynamically adjusts memory rail voltage by comparing sensor indications to an expected value, allowing for incremental voltage adjustments to minimize leakage power dissipation while ensuring data retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If supply voltage is reduced to minimize power consumption, then power efficiency is improved, but memory data retention reliability deteriorates
Solution Approach 1:
The system segments the memory system into sensor cells and data storage bitcells, allowing independent voltage monitoring and control. The sensor cells are further segmented into multiple groups that can be tested at different voltage thresholds, enabling granular power optimization without compromising overall memory reliability.
Solution Approach 2:
The system implements feedback through sensor cells that continuously monitor voltage levels and provide indications to the controller. When sensor cells fail to retain data, the controller receives feedback and adjusts the supply voltage upward to prevent actual data loss, creating a closed-loop control system that balances power consumption with reliability.
2Reliability
If supply voltage is increased to ensure data retention, then memory reliability is improved, but power consumption increases
Solution Approach 1:
The system dynamically adjusts the memory supply voltage based on real-time sensor cell performance rather than maintaining a static voltage level. The controller continuously monitors sensor cell outputs and adjusts voltage in response to changing conditions, enabling the system to operate at minimum necessary voltage levels while ensuring data retention when needed.
Solution Approach 2:
The system changes the voltage parameter dynamically based on sensor cell failure thresholds. By monitoring when sensor cells fail to retain data and adjusting the supply voltage accordingly, the system optimizes the voltage parameter to the minimum level required for reliable operation, reducing unnecessary power consumption at higher voltage levels.
3Use of energy by moving object
If dynamic voltage adjustment is implemented across the entire IC, then power optimization is improved, but system complexity increases due to multiple supply domains and device heterogeneity
Solution Approach 1:
The system extracts the voltage monitoring and sensing function into separate sensor cells that are independent of the main data storage bitcells. This allows the complex sensing and control logic to be isolated from the bulk memory array, simplifying the overall system architecture while enabling sophisticated power management.
Solution Approach 2:
The sensor cells serve multiple functions: they act as voltage threshold indicators, data retention monitors, and control signals for voltage adjustment. This multi-functionality reduces the need for separate dedicated components for each function, thereby reducing overall system complexity while achieving comprehensive power optimization.
Data Source
AI summary
Systems and methods for optimizing a memory rail voltage are disclosed. The system may comprise a plurality of sensor cells, each sensor cell comprising at least one bitcell replica having a predefined data retention voltage higher than a data retention voltage of a similar memory bit cell. The sensor cells may be configured to provide an output based on a sensor rail voltage higher than the predefined data retention voltage. The system may further comprise a controller operably coupled to a power management circuit and configured to adjust the memory rail and the sensor rail voltages. The controller may be further configured to compare an expected value to the sensor indication. The controller may decrease the sensor rail voltage and the memory rail voltage based on the indication until a sensor indicates a bitcell replica has failed, indicating an optimum memory rail voltage has been reached.