High-Power PSU Compatibility Design

flux

I’ll compare the efficiency and lifetime cost of reused 12 V server PSUs against direct 19.5 V supplies, and check how interchangeable PSU input adapters would fit the architecture. I’ll separate verified ratings from estimates; your exact PSU model and operating load are still needed for a definitive comparison.

flux

The comparison confirms that fewer conversion stages do not automatically mean better efficiency: industrial supplies vary substantially. Dell also documents some 1100 W units as limited to 1050 W at 120 VAC, and programmable 24 V alternatives need their current derating checked before treating them as kilowatt-class 19.5 V supplies.
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Power Conversion Tradeoffs

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Power Conversion Tradeoffs Conclusion
Reused server PSUs plus synchronous boost converters are a credible low-capital-cost architecture, not necessarily the most energy-efficient one. The decision must compare measured wall-to-load efficiency and total installed cost, not the number of external conversion stages. No schematic or layout changes were made for this analysis.
The user reports approximately $15 for used 1100W server PSUs with 12V/85A output. This price and the exact unit rating are user-provided, not independently verified. The existing project specification identifies Dell D750E-S1 as the original 750W target and approximately 180W per slot. Its PSU ratings remain project assumptions here, not newly verified label data. The 1100W model under consideration is unidenti...

flux

Server-PSU reuse still makes economic sense, but for continuous high-load use I’d compare it against direct 19.5 V distribution—including the cost of all boost boards and cooling, not just the $15 PSU. I saved the researched alternatives, efficiency/payback calculations, and interchangeable input-adapter recommendation in your project files: Power Conversion Tradeoffs; no hardware was changed.
Your original specification names a 750 W PSU, while the proposed 1100 W model remains unidentified—what exact model are you considering, and what average total load and hours/day do you expect?

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Schematic

Layout

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Schematic Capture Status — Organized Two-Module Pass
Status
The project schematic has been simplified and organized into two representative modules:
  1. Distribution Board — upstream PSU input protection/control and one representative daughterboard slot.
  2. 19.5V Boost 180W Module — one representative LM5122 boost daughterboard.
This is now a representative architecture schematic, not a 12× replicated schematic.
Distribution Board — Current Representative Blocks
  • Upstream input eFuse: TPS259827ONRGET (U_IN_EFUSE).
  • Input TVS: SMBJ15A (D_IN_TVS).
  • Input bulk/filtering capacitor banks.
  • MCU module: Raspberry Pi Pico 2 (U_MCU).
  • One representative per-slot blade fuse holder (FH_SLOT).
  • One representative slot enable MOSFET scaffold (Q_SLOT_EN).
  • One enable buffer (U_SLOT_BUF).
  • Placeholder 32-pin slot connector (J_SLOT) using X4622WVS-2x16I-C40D64-E60.
  • System status LED and current-limit resistor.
Distribution Board — Removed / Simplified
  • Removed the 11 duplicate slot fuse holders (H1–H11).
  • Removed the 11 duplicate slot MOSFETs (Q2–Q12).
  • Removed the 11 duplicate enable buffers (U4–U14).
  • Removed unused helper resistors (R3, R4, R5, R_MCU_SER).
Representative Slot Pinout
J_SLOT is wired as a placeholder for one full daughterboard slot:
  • Pins 1,3,5,7,9,11,13,15,17,19 → GND.
  • Pins 2,4,6,8,10,12,14,16,18,20 → SLOT1_12V.
  • Pin 21 → SLOT1_GATE / enable path placeholder.
  • Pin 22 → SLOT1_MODE.
  • Pin 23 → SLOT1_SYNC.
  • Pin 24 → SLOT1_FAULT_N.
  • Pin 25 → SLOT1_PGOOD.
  • Pin 26 → IIN_SENSE.
  • Pin 27 → IOUT_SENSE.
  • Pin 28 → TEMP_MOS.
  • Pin 29 → TEMP_IND.
  • Pin 30 → VOUT_CONN as placeholder VOUT sense.
  • Pin 31 → MOD_PRESENT_N.
  • Pin 32 → SLOT_ID_SPARE.
19.5V Boost 180W Module — Current Representative Blocks
  • LM5122 controller (U1).
  • Two BSC010NE2LS MOSFETs (Q1, Q_BOOST_HS).
  • Boost inductor (L_BOOST).
  • Input/output capacitor banks from the user BoM.
  • Input and output current shunts (R_SHUNT_IN, R_SHUNT_OUT).
  • Input/output INA181 current monitors (U2, U3).
  • Feedback and compensation networks.
  • Output TVS (D_OUT_TVS).
  • MOSFET and inductor thermistor telemetry (RT_DB, R1).
  • Placeholder DC output jack (J_DC_OUT) using PJ-037A.
Known Placeholders
  • J_SLOT is not the final ED32BGFBK footprint; it is a usable schematic placeholder with 32 terminals.
  • J_DC_OUT is not the final DC-S007B-D025-15A 15A jack; it is a random usable 2-terminal DC barrel jack placeholder.
  • The imported ED32BGFBK and DC-S007B-D025-15A part projects remain footprint-only until repaired manually.
Validation Notes
  • Current schematic summary: 64 BOM instances, 33 nets.
  • ERC still reports floating MCU GPIO warnings and incomplete support pins, which is expected at this stage.
  • Real engineering validation still needed for TPS259827 support pins, LM5122 compensation/power-stage values, and the final slot enable/high-side switch topology.
  1. Finish TPS259827 support network: ILIM, ITIMER, dVdt, EN/UVLO, PG, retry behavior.
  2. Decide whether Q_SLOT_EN remains, becomes a proper high-side switch, or is removed for fuse-only Rev A.
  3. Validate LM5122 power-stage values with TI calculator/datasheet.
  4. Repair final ED32BGFBK and DC-S007B-D025-15A parts later, then replace placeholders before PCB layout.

  • Status

  • Distribution Board — Current Representative Blocks

  • Distribution Board — Removed / Simplified

  • Representative Slot Pinout

  • 19.5V Boost 180W Module — Current Representative Blocks

  • Known Placeholders

  • Validation Notes

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