Solid State Latching Relay (SSLR)

Invocon’s Solid State Latching Relay (SSLR) provides isolated, regulated, redundant control over an external power source and its load. The SSLR is a power termination solution for Flight Termination Systems (FTS) whose mode of operation is thrust termination. It accepts two TERMINATE signals from up to two Flight Termination Receivers (FTRs) in a cross-strapped configuration, where either TERMINATE signal can latch off both internal components to cut power to the load. The SSLR was designed to the RCC 319-19 standard.

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Key Specifications

Specification
Value
Load Power Input
26 to 45 Vdc at up to 4.8 A
Load Power Output
Single fixed voltage, 5V to 21V step-down regulated, up to 4.8 A
Control / Latch Input Voltage
Nominal 28 Vdc
Latch Open Threshold
>15.1 Vdc per TERMINATE signal
Internal Switch Default State
Normally Closed (power provided to load)
Power Dropout Survivability (latched open)
Up to 50 ms
TM Status Output
0–5 Vdc scaled for power, on/off state, and control signal monitoring
Standard Compliance
RCC 319-19

Key Features

  • Cross-Strapped Redundant TERMINATE Inputs

    Accepts TERMINATE signals from two independent FTRs in a cross-strapped configuration — either signal can independently latch off both internal components.

  • Isolated, Regulated Load Output

    Provides a fixed step-down regulated output voltage (5V–21V, customizable) that is electrically isolated from the control circuit.

  • Normally Closed Fail-Safe Architecture

    Internal switch defaults to closed (power provided to load), with latch-open state requiring a positive TERMINATE input, consistent with FTS fail-safe design philosophy.

  • Power Dropout Survivability

    Maintains the latched open state through input power dropouts of up to 50 ms, preventing inadvertent reset during transient power interruptions.

  • TM Status Output

    0–5 Vdc telemetry status output enables real-time monitoring of load power level, on/off state, and TERMINATE control signals.

  • RCC 319-19 Compliant Design

    Designed to RCC 319-19 range safety standard for use in FAA and DoD range FTS applications.

Typical Applications

  • FTS Thrust Termination

    Cuts power to a thrust-producing device upon receipt of a TERMINATE command from an FTR for range safety compliance.

  • Dual-FTR Cross-Strapped Activation

    Supports FTS architectures requiring either of two independent FTR TERMINATE outputs to command power cutoff.

  • Load Isolation and Protection

    Provides regulated isolated power to sensitive loads that require protection from the raw FTS bus voltage.

  • Telemetry Health Monitoring

    Feeds TERMINATE command and power state data into the vehicle telemetry stream for post-flight range safety review.

Available Configurations

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