DICE Latch Write Path Staggering Against Upstream Neutron Strikes
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Solution Overview
Problem
Dual-interlocked cell (DICE) latches are robust against single neutron strikes but vulnerable to double neutron strikes, which can cause data failures due to simultaneous propagation of neutron strikes through separated control paths.
Innovation Solution
Implementing staggered write control by introducing a delay in one of the control paths of the DICE latch to stagger the propagation of neutron strikes, ensuring the latch can recover from single strikes without mimicking a double strike failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separated control paths are used in DICE latches, then resistance to single neutron strikes is improved, but vulnerability to double neutron strikes and upstream neutron strikes increases
Solution Approach 1:
The patent applies preliminary action by introducing a delay element in one of the control paths before the DICE latch, causing control signals to arrive at different times. This staggering of control signal arrival times ensures that if a neutron strike occurs upstream, the latch recovers from the first strike before the second strike can propagate through both control paths simultaneously, thereby preventing double-strike failures while maintaining single-strike resistance
Solution Approach 2:
The patent segments the control signal path into two separate paths with different delay characteristics. By dividing the control function into parallel paths that process signals at different times, the system achieves fault tolerance against neutron strikes. The segmentation allows one path to be delayed while the other responds immediately, creating temporal separation that prevents simultaneous failure modes
2Reliability
If delay is introduced in control paths to stagger neutron strike propagation, then resistance to upstream neutron strikes is improved, but device complexity increases
Solution Approach 1:
The delay element is positioned in advance in the control signal path, before the DICE latch receives the control signals. This preliminary delay ensures that control signals are staggered in their arrival at the latch, providing time for the latch to recover from upstream neutron strikes before both paths can be affected simultaneously, thereby improving reliability with minimal added complexity
Data Source
AI summary
Systems and methods include a memory device that includes a dual-interlocked cell (DICE) latch and upstream circuitry coupled to the DICE latch and including a common node configured to receive a control signal for an operation for the DICE latch. The upstream circuitry also includes a first divided control path coupled to common node and configured to generate a first divided control signal from the control signal. The upstream circuitry comprises a second divided control path coupled to the common node and configured to generate a second divided control signal from the control signal. The second divided control path includes a delay configured to delay the second divided control signal to stagger propagation of a potential neutron strike at the common node or upstream of the common node from the DICE latch.