5-Channel UMPPT PCDU — 28 V Unified Bus, 212.6 W

Overview

A Power Conditioning and Distribution Unit for a 2-week LEO CubeSat mission — five independent MPPT channels combined onto a regulated 28 V bus, with supercapacitor transient buffering and full protection.

Challenge

Design a 5-channel UMPPT PCDU delivering 212.6 W on a 28 V unified bus with supercapacitor buffering, per-channel EMI filtering, and full OBC telemetry — all COTS parts derated per NASA GSFC-STD-7000.

Our Approach

• 5-channel UMPPT topology with LT8490 per panel
• Supercapacitor buffer (2x BCAP0350, 175F/5V) for pulsed loads
• Two-stage EMI filtering with TVS clamping per channel
• INA181A1 high-side sensing into ADS7953 ADC array
• Layered protection: circuit breakers, opto isolation, fuel gauge

Technical Highlights

• 5-channel UMPPT with independent MPPT per solar panel
• 28 V unified bus distributing 3.3V, 5V and 28V rails
• Supercapacitor transient buffering — no battery, direct solar feed
• All COTS ICs derated per NASA GSFC-STD-7000

Deliverables

• ✓Full design and analysis report
• ✓Annotated board documentation
• ✓Fabrication-ready layout
• ✓Component derating analysis