Process Tolerant SRAM Voltage Source
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Solution Overview
Problem
Integrated circuits face performance issues due to process variations during manufacturing, particularly affecting SRAMs' ability to write data effectively at certain process corners, necessitating a solution for tolerance to these variations.
Innovation Solution
A voltage source is configured to adjust its output voltage based on the electrical parameters resulting from process variations, using a p-channel headswitch, a p-channel pull-down device, and a dummy voltage generator to emulate capacitive loading, thereby assisting write operations in SRAMs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If integrated circuits are manufactured using standard CMOS processes, then manufacturing cost and reliability are improved through batch production, but process variations during manufacturing cause electrical parameter deviations that worsen circuit performance at process corners
Solution Approach 1:
The patent applies dynamics by making the voltage supply adjustable rather than fixed. The voltage source dynamically adapts its output voltage based on the specific circuit's process corner characteristics, allowing the system to optimize performance for each individual circuit instance while maintaining batch manufacturing benefits.
Solution Approach 2:
The patent changes the voltage parameter to compensate for process variations. By adjusting the supply voltage based on measured or characterized electrical parameters of individual circuits, the system compensates for manufacturing variations and ensures reliable operation at all process corners.
2Device complexity
If SRAM is designed for standard operation, then circuit complexity is kept low, but writing capability deteriorates at SF process corner where slow NMOS and fast PMOS transistors cause difficulty
Solution Approach 1:
The patent applies local quality by providing tailored voltage adjustment for each SRAM circuit based on its specific process corner characteristics. Instead of redesigning the entire SRAM array, individual voltage sources adjust local supply voltage to compensate for the specific NMOS/PMOS speed mismatch at SF corner.
Solution Approach 2:
The patent performs preliminary characterization of each SRAM circuit's electrical parameters during manufacturing, then uses this information to pre-configuring the voltage source settings before the circuit begins operation, ensuring optimal write capability from the start.
3Reliability
If voltage is adjusted as a function of electrical parameters to compensate for process variations, then circuit performance reliability is improved, but device complexity increases due to additional voltage source components
Solution Approach 1:
The patent implements self-service by having each voltage source automatically adjust its output based on the electrical parameters of its associated circuit. The voltage source monitors or receives feedback about the circuit's process corner characteristics and autonomously optimizes the supply voltage without requiring external intervention.
Solution Approach 2:
The patent creates a universal voltage source design that can serve multiple functions: it provides power supply, performs process corner compensation, and adapts to different circuit types (SRAM, logic, etc.). This multi-functionality reduces the need for separate compensation circuits for each circuit type.
Data Source
AI summary
Various integrated circuits and methods of operating the integrated circuits are disclosed. The integrated circuit may include a circuit having one or more electrical parameters resulting from process variations during the manufacture of the integrated circuit, and a voltage source configured to supply a voltage to the circuit to power the circuit, wherein the voltage source is further configured to adjust the voltage as a function of the one or more electrical parameters.