Register File Write Ring Oscillator Test Circuit
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Solution Overview
Problem
Variations in electrical characteristics of data storage cells in register files due to manufacturing and aging effects can lead to data storage failures, particularly at different power supply voltages, causing processors or SoCs to fail in storing data within a predetermined clock cycle, necessitating re-design to meet manufacturing yield goals.
Innovation Solution
A circuit and method for testing register files that involves reading data from a selected cell, inverting and re-storing it, and measuring read-write oscillation frequencies to determine the write frequency, using a frequency divider to generate a test output and calculate the write frequency based on these measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If data storage cells are designed with identical characteristics, then manufacturing complexity is reduced, but variations in electrical characteristics due to lithography and dopant variations cause data storage failures
Solution Approach 1:
The patent measures the actual write time of each data storage cell and uses this measured parameter to dynamically adjust the write enable signal timing. By changing the operational parameters based on measured characteristics rather than relying on fixed design specifications, the system accommodates variations in electrical characteristics caused by manufacturing processes while maintaining data storage reliability.
2Productivity
If the processor operates at higher speeds, then productivity is improved, but data storage cells require different amounts of time to store data, causing failures at predetermined clock cycle periods
Solution Approach 1:
The patent implements a dynamic write time adjustment mechanism where the write enable signal is timed based on measured write characteristics of each cell rather than a fixed clock cycle period. This dynamic adaptation allows the system to operate at higher speeds while accommodating the varying storage times of different cells, preventing data storage failures that would occur with rigid timing constraints.
3Use of energy by moving object
If power supply voltage is reduced, then energy consumption is reduced, but data storage cells fail to store data within the predetermined clock cycle period
Solution Approach 1:
The patent performs preliminary measurement of write times for each data storage cell at the actual operating power supply voltage before normal operation. These pre-measured characteristics are stored and used to pre-calculate appropriate write enable signal timing. This preliminary characterization allows the system to compensate for reduced power supply voltage effects during low-power operation, maintaining data storage reliability while operating at lower energy consumption levels.
Data Source
AI summary
Embodiments of a register file test circuit are disclosed that may allow for determining write performance at low power supply voltages. The register file test circuit may include a decoder, a multiplexer, a frequency divider, and a control circuit. The decoder may be operable to select a register cell within a register file, and the control circuit may be operable to controllably activate the read and write paths through the selected register cell, allowing data read to be inverted and re-written back into the selected register cell.