Project brief
A high-reliability power distribution board for an avionics bay, accepting MIL-STD-704F 28VDC aircraft power bus (16–40V input range) and providing clean regulated power to 8 independent avionics subsystems. GaN FETs are used for the DC-DC conversion stages to achieve >94% conversion efficiency at full load while minimizing weight for airborne application.
The record describes a power-board architecture combining conversion, protection, and subsystem-level monitoring; the explanatory view adds no efficiency measurements.
The engineering challenge
Distribute aircraft input power to multiple subsystems while handling transients, load changes, and faults.
Engineering approach
- Place input protection ahead of the conversion and distribution stages.
- Treat each output as an independently monitored power channel.
- Combine enable control, fault recovery, and power-good telemetry.
Features & capabilities
- Input: 16–40VDC MIL-STD-704F compliant with transient protection per DO-160G
- 8 independent regulated outputs: 3.3V (5A), 5V (5A), 12V (3A), 28V (2A) ×5
- Peak efficiency >94% at full 120W load using GaN FETs
- EMI/EMC compliance to DO-160G Section 21 (Category Z)
- Hot-plug subsystem enable/disable control via I2C bus
- Over-current (per-output), over-voltage, and over-temperature protection
- Power good signals and telemetry output for system monitoring
- Short-circuit current limiting — hiccup mode recovery
Software & engineering tools
Altium Designer, LTC3891 multi-phase controller, GaN FETs (GS66508T), 6-layer PCB, conformal coating