SSPC Control Circuit Backup Latch for Radiation Upsets
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Solution Overview
Problem
Aerospace solid state power controllers (SSPCs) face challenges with neutron radiation, causing Single Event Upsets (SEU) or Single Event Latch-ups (SEL) in microcontrollers, leading to undesirable power disruptions in aircraft systems, as commercially available components are not tested for radiation susceptibility and cycling control power to mitigate these events results in temporary power losses.
Innovation Solution
A control circuit with a primary controller and an auxiliary circuit supplies a control voltage to a solid state switching device, using a memory unit to store the previous state of the control terminal signal, allowing the auxiliary circuit to maintain the switching state during primary controller failures due to SEU or SEL, ensuring continuous operation without output state changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cycling control power to the microcontroller is implemented to mitigate SEU or SEL events, then the reliability of the microcontroller is improved, but the productivity of the power distribution system deteriorates due to temporary power losses
Solution Approach 1:
The auxiliary circuit is pre-configured with a latch mechanism that stores the previous state of the control terminal. When the primary controller experiences an SEU or SEL event, the auxiliary circuit immediately activates to maintain the switching device in its previous state, preventing any interruption in power distribution. This preliminary preparation of the auxiliary circuit allows it to take over instantly without requiring power cycling.
Solution Approach 2:
The auxiliary circuit acts as an intermediary between the primary controller and the switching device. It includes a latch that captures the control terminal state and a control voltage generator that reproduces the appropriate control voltage. This intermediary structure allows the system to bridge over SEU or SEL events without transmitting their disruptive effects to the power distribution output.
2Ease of manufacture
If commercially available microcontrollers are used in SSPCs, then the ease of manufacture is improved, but the reliability deteriorates due to susceptibility to neutron radiation
Solution Approach 1:
The patent implements a protective cushioning mechanism by adding the auxiliary circuit with latch and control voltage generator. This auxiliary structure is designed beforehand to compensate for potential SEU or SEL events. When radiation strikes the microcontroller, the auxiliary circuit is already in place to detect the failure condition and immediately take over, cushioning the system against the harmful effects of neutron radiation.
Solution Approach 2:
The system changes the operational parameter of the control terminal by switching between primary controller operation and auxiliary circuit operation. The auxiliary circuit modifies the control voltage parameter to maintain the switching device state even when the primary controller fails due to radiation effects. This parameter change allows continued reliable operation with standard commercial microcontrollers despite their radiation susceptibility.
Data Source
AI summary
A control circuit configured to supply a control voltage to a control terminal (G) of a solid state solid state switching device of a solid state power controller. The control circuit comprises: a primary controller operative to supply a primary control voltage to the control terminal (G) of the solid state switching device; and an auxiliary circuit configured to supply an auxiliary control voltage to the control terminal (G) of the solid state switching device in case the primary controller falls into an inoperative condition.