SSPC Control Circuit With Auxiliary Gate Hold During SEU Reset
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Solution Overview
Problem
Aerospace electronic systems, particularly solid state power controllers, are susceptible to neutron radiation-induced Single Event Upsets (SEU) and Single Event Latch-ups (SEL), leading to undesirable power disruptions and operational failures, as commercially available microcontrollers are not tested for such conditions and cycling control power to mitigate these issues results in temporary SSPC shutdowns.
Innovation Solution
A control circuit with an auxiliary control voltage mechanism that maintains the state of the solid state switching device by storing the primary control voltage in a simple memory unit, such as a flip-flop, and providing it as an auxiliary voltage during primary controller failures, ensuring seamless operation and preventing changes in the SSPC output state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cycling control power to the microcontroller is used to mitigate neutron radiation susceptibility, then the microcontroller can be reset from SEU or SEL conditions, but the SSPC momentarily turns off causing disruption to electrical loads
Solution Approach 1:
The control circuit stores the last valid control voltage state in a memory element (flip-flop) before the microcontroller fails. When the microcontroller becomes inoperative due to neutron radiation, the stored control voltage is immediately provided to the solid state switching device, maintaining its state without requiring a power cycle that would disrupt loads.
Solution Approach 2:
An auxiliary control circuit acts as an intermediary between the microcontroller and the solid state switching device. This intermediate circuit includes a memory element that holds the control voltage state and can independently drive the switching device when the microcontroller fails, preventing direct disruption to the power distribution.
2Ease of manufacture
If commercially available microcontrollers are used in SSPC, then cost and availability are improved, but susceptibility to neutron radiation-induced SEU and SEL increases
Solution Approach 1:
The control circuit incorporates a memory element that continuously holds the control voltage state as a backup. This provides a cushion against neutron radiation effects by having a pre-stored valid state ready to take over immediately when the microcontroller experiences SEU or SEL, without requiring specialized radiation-hardened components.
Solution Approach 2:
The auxiliary control circuit with its memory element serves as a protective intermediary layer between the vulnerable commercial microcontroller and the critical power switching function. This intermediary can isolate the switching device from microcontroller failures caused by neutron radiation.
3Reliability
If the primary controller falls into an inoperative condition, then neutron radiation effects are mitigated, but the control voltage to the solid state switching device is lost causing output state changes
Solution Approach 1:
The memory element in the control circuit continuously stores the control voltage state in advance. When the microcontroller becomes inoperative, this pre-stored voltage maintains the solid state switching device in its last valid state, preventing any changes in the SSPC output state that would otherwise occur due to loss of control voltage.
Solution Approach 2:
The control circuit ensures continuous provision of control voltage to the solid state switching device by using the memory element to supply the stored control voltage when the microcontroller fails. This continuity prevents interruption of the switching device operation and maintains stable SSPC output state despite microcontroller inoperability.
Data Source
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AI summary
The present disclosure relates to a control circuit (10) configured to supply a control voltage to a control terminal (G) of a solid state solid state switching device (12) of a solid state power controller (100), the solid state switching device (12) having a first terminal (D), a second terminal (S), and the control terminal (G), the solid state switching device (12) configured to switch between an OFF operation mode in which the second terminal (S) is electrically disconnected from the first terminal, and an ON operation mode in which the second terminal (S) is electrically connected to the first terminal (D), according to the control voltage applied to the control terminal (G). The control circuit (10) comprises: a primary controller (16) operative to supply a primary control voltage to the control terminal (G) of the solid state switching device (12; and an auxiliary circuit (18) configured to supply an auxiliary control voltage to the control terminal (G) of the solid state switching device (12) in case the primary controller (16) falls into an inoperative condition. The present disclosure also relates to a solid state power controller (100) comprising such control circuit.