A Novel MOSFET-Based Circuit for Detecting, Limiting, and Recovering from Single Event Latchup in Spacecraft Systems

Основные понятия

This paper presents a novel circuit design that can detect, limit the current, and execute self-power cycling to recover from Single Event Latchup (SEL) in CMOS ICs used in spacecraft systems.

Аннотация

The paper presents a novel circuit design to address the problem of Single Event Latchup (SEL) in CMOS ICs used in spacecraft systems. The key highlights are:

1. Current Limiting: The circuit employs MOSFETs to limit the supply current during an SEL event, ensuring the device under protection never enters a high current state that could cause permanent damage.

2. SEL Detection: The circuit detects the SEL event by monitoring the voltage drop across the current limiting MOSFET, which increases during an SEL event.

3. Self Power Cycling: Upon detecting an SEL event, the circuit automatically switches off the SEL-prone device and then restores its normal function after a set interval of time, allowing the latchup condition to clear.

The proposed circuit provides a comprehensive end-to-end solution for SEL mitigation, offering reliability assurance for spacecraft systems operating in harsh space radiation environments. Simulation results demonstrate the circuit's ability to limit the current to a safe threshold and execute the power cycling recovery within a few tens of milliseconds, minimizing the loss in functionality.

The key advantages of this design over conventional SEL mitigation techniques are:

• Absolute certainty that the SEL-sensitive device will never enter a high current state
• Automated recovery of normal device operation after an SEL event
• Flexibility to tune the off-time duration based on the specific device requirements
• No continuous power dissipation during normal operation

Статистика

The current through the simulated SEL-prone device is limited to the following threshold values during an SEL event:

450 mA
150 mA
50 mA
12 mA
The total time for which the device remains turned off after an SEL event is approximately 83.33 milliseconds, which matches well with the theoretical estimation of 83.645 milliseconds.

Цитаты

"The proposed circuit has been simulated in MULTISIM and the simulation results match very well with the expected behavior of (i) current limiting and (ii) the total time duration taken in power cycling to bring the SEL sensitive device back to its normal operational state."
"This circuit can be harnessed by spacecraft system designers to overcome the catastrophic threat of SEL posed by space radiation environment."

Ключевые выводы из

A Novel MOSFET based Single Event Latchup Detection, Current Limiting & Self Power Cycling circuit for Spacecraft systems

by Ishan Pandey... в arxiv.org 09-26-2024

https://arxiv.org/pdf/2409.17056.pdf

Дополнительные вопросы

How can this circuit design be extended to handle multiple SEL-prone devices in a spacecraft system?

To extend the proposed MOSFET-based Single Event Latchup (SEL) detection and mitigation circuit for multiple SEL-prone devices in a spacecraft system, several strategies can be employed:

Parallel Configuration: The circuit can be replicated for each SEL-prone device, with each circuit connected in parallel to the power supply. Each device would have its own MOSFET Q1 for switching, MOSFET Q2 for current limiting, and associated components for detection and power cycling. This ensures that each device is independently monitored and protected against SEL events.

Shared Detection and Control Logic: A centralized detection and control logic can be implemented, where a single comparator (or multiple comparators) monitors the current across multiple devices. If an SEL event is detected in any device, the control logic can trigger the corresponding MOSFETs to turn off the affected device while allowing others to continue operating normally. This approach reduces component count and complexity.

Dynamic Current Limiting: The design can incorporate adjustable current limiting thresholds for each device based on their specific operational requirements. This can be achieved by using programmable voltage references for VGS of MOSFET Q2, allowing for tailored protection strategies for different devices.

Time-Division Multiplexing: In scenarios where devices can tolerate brief interruptions, a time-division multiplexing approach can be used. The circuit can cycle through devices, applying power to one at a time while monitoring for SEL events. This method can optimize power usage and reduce the overall complexity of the circuit.

Communication Interface: Implementing a communication interface among the circuits can facilitate coordination and data sharing regarding SEL events. This can enhance the overall system reliability by allowing devices to share information about their operational status and SEL occurrences.

By employing these strategies, the circuit design can effectively manage multiple SEL-prone devices, ensuring robust protection and operational continuity in the harsh space radiation environment.

What are the potential trade-offs between the current limiting threshold, power cycling duration, and the overall system reliability and performance?

The design of the current limiting threshold, power cycling duration, and their impact on overall system reliability and performance involves several trade-offs:

Current Limiting Threshold:

Higher Thresholds: Setting a higher current limiting threshold may allow devices to operate closer to their maximum ratings, potentially improving performance during normal operation. However, this increases the risk of entering a high current state during an SEL event, which could lead to device damage.
Lower Thresholds: Conversely, a lower current limiting threshold enhances protection against SEL events but may restrict the device's performance and operational capabilities, especially under high load conditions.

Power Cycling Duration:

Shorter Duration: A shorter power cycling duration can minimize downtime and improve system responsiveness after an SEL event. However, if the duration is too short, it may not allow sufficient time for the latchup condition to dissipate, risking repeated latchup occurrences.
Longer Duration: Extending the power cycling duration ensures that the device has ample time to recover from latchup conditions, enhancing reliability. However, this can lead to increased system downtime, which may not be acceptable in critical applications.

Overall System Reliability:

The balance between current limiting and power cycling duration directly affects the reliability of the system. A well-calibrated current limiting threshold combined with an appropriate power cycling duration can significantly enhance the reliability of SEL-prone devices. However, misalignment in these parameters can lead to increased susceptibility to SEL events or prolonged outages.

Performance Trade-offs:

The performance of the spacecraft system may be compromised if the current limiting threshold is set too low or if the power cycling duration is excessively long. This can affect mission-critical operations, especially in scenarios requiring high power or rapid response times.

In summary, careful consideration and optimization of the current limiting threshold and power cycling duration are essential to achieve a balance between protecting SEL-prone devices and maintaining overall system performance and reliability.

Could this circuit design be adapted to address other types of single-event effects, such as single-event upsets, in addition to single-event latchup?

Yes, the proposed circuit design can be adapted to address other types of single-event effects (SEEs), including single-event upsets (SEUs), in addition to single-event latchup (SEL). Here are several ways this adaptation can be achieved:

Enhanced Detection Mechanisms: The circuit can incorporate additional detection mechanisms to identify SEUs, which typically manifest as transient changes in the output state of digital circuits. By integrating additional comparators or logic gates that monitor the output states of critical components, the circuit can detect anomalies indicative of SEUs.

Redundant Circuitry: Implementing redundancy in critical components can help mitigate the effects of SEUs. For instance, using dual or triple modular redundancy (DMR/TMR) can ensure that even if one component experiences an upset, the overall system can continue to function correctly by relying on the outputs of the redundant components.

Adaptive Power Cycling: The power cycling mechanism can be adapted to not only turn off devices during SEL events but also to reset or reinitialize components that have experienced SEUs. This can involve a more sophisticated control logic that differentiates between SEL and SEU events, allowing for tailored responses.

Error Correction Codes (ECC): For digital circuits, integrating error correction codes can help detect and correct SEUs without requiring a complete power cycle. The circuit can be designed to monitor data integrity and apply corrections as needed, thus enhancing resilience against SEUs.

Monitoring and Feedback Loops: Incorporating monitoring circuits that provide feedback on the operational status of devices can help in identifying SEUs. This feedback can be used to trigger corrective actions, such as reinitializing a device or switching to a backup system.

Flexible Current Limiting: The current limiting feature can be adjusted to account for the different characteristics of SEUs, which may not necessarily involve high current states but rather transient voltage spikes. This flexibility can enhance the circuit's ability to handle a broader range of SEEs.

By implementing these adaptations, the circuit design can effectively address not only SEL but also other single-event effects, thereby enhancing the overall reliability and robustness of spacecraft systems in the challenging space radiation environment.