FPGA Memory Cell Redundancy for Single Event Effect Mitigation
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Solution Overview
Problem
Field-Programmable Gate Arrays (FPGAs) in aerospace applications are prone to Single Event Upsets (SEUs) and Single Event Transients (SETs) due to particle interactions, leading to functional errors, and existing mitigation methods like Triple Modular Redundancy (TMR) result in performance degradation and increased design complexity.
Innovation Solution
Incorporating an integrated particle sensor that detects ionizing particles and dynamically switches between faulty and redundant memory cells, enabling instantaneous error detection and reconfiguration, thereby reducing the Time-In-Error (TIE) and maintaining design capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Triple Modular Redundancy (TMR) is used to mitigate SEU/SET, then reliability is improved, but device complexity increases and productivity decreases due to 3x reduction in Maximal Design Capacity
Solution Approach 1:
The invention divides the FPGA into multiple regions with different hardening levels. Critical regions receive full radiation hardening while non-critical regions use standard cells, allowing selective application of redundancy measures rather than uniform TMR across the entire device.
Solution Approach 2:
Different areas of the FPGA are assigned different quality levels of radiation hardening. Time-in-error monitoring is applied selectively to critical functions, while less critical areas use simpler protection schemes, optimizing the balance between reliability and resource utilization.
2Reliability
If bitstream scrubbing is used to address SEU/SET, then reliability is improved, but productivity decreases due to significant negative performance impact and variable detection time
Solution Approach 1:
The system continuously monitors time-in-error metrics and automatically triggers reconfiguration or correction actions when thresholds are exceeded, eliminating the need for external intervention or manual scrubbing schedules. The FPGA self-manages its radiation error correction based on real-time performance data.
Solution Approach 2:
Time-in-error monitoring provides continuous feedback about the actual performance impact of radiation errors. This feedback drives dynamic reconfiguration decisions, allowing the system to correct errors only when they actually affect performance, rather than using continuous or periodic scrubbing that degrades performance regardless of actual error conditions.
3Reliability
If radiation hardening is applied to minimize SEU/SET probability, then reliability is improved, but manufacturing precision requirements increase due to specialized fabrication processes like SOI
Solution Approach 1:
The FPGA device is segmented into hardened and non-hardened regions, allowing standard fabrication processes to be used for the majority of the device while applying specialized radiation-hardened processes only to specific critical regions, thereby reducing overall manufacturing complexity.
Solution Approach 2:
The invention merges standard CMOS fabrication processes with radiation-hardened processes in a single device. By integrating both hardened and non-hardened regions in one FPGA, the system achieves radiation resistance where needed while maintaining compatibility with standard manufacturing workflows for the remainder of the device.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides a 33.33% enhancement in Maximal Design Capacity (MDC) with a 41.08% area increase for 40 nm technology nodes, outperforming bitstream scrubbing by 10,000 times in TIE reduction and allowing a 1.7% area reduction compared to Rad-Hard 12T architectures without performance loss.
Implementation Method 1
the integrated particle sensor can be operable to detect an ionizing particle generating the single event effect
Data Source
AI summary
Electronic devices and methods for single event effect mitigation are described. The device can include a processor, a memory cell, and an integrated particle sensor. The memory cell can comprise a substrate, a deep well coupled to the substrate, and a ground-coupled well coupled to the deep well. The integrated particle sensor can be coupled between the substrate and the deep well, and the ground-coupled well and the deep well. The integrated particle sensor can be operable to detect an ionizing particle generating the single event effect. The electronic device can be a field-programmable gate array. The method can include detecting an ionizing particle generating a single event effect at a memory cell of the electronic device, switching from the memory cell to a redundant memory cell associated with the memory cell when the single event effect is detected, and reconfiguring the memory cell based on the redundant memory cell.