Done. I deleted CN1 and moved U_MCU/Pico to the top of the board; it is now centered at about (10 mm, 88 mm) with its top edge just inside the board outline.
Open item: the Pico was clamped at the board edge, so if you want more clearance from the top edge I can drop it slightly lower.
I’ll add a low-current front-panel power/enable switch rather than a high-current 12 V path switch, plus output/status LEDs with current-limiting resistors, then verify the schematic changes.
Added the power switch and output LEDs. SW_PWR is a low-current front-panel switch that pulls Pico 3V3_EN to GND to turn logic off, and I added green indicators for BUS_12V and VOUT_19V5 with 4.7kΩ and 8.2kΩ series resistors.
Open items:
These are placed near the top/front-panel area but not routed yet.
If you intended a true high-current input disconnect instead of a Pico enable switch, that needs a different switch/contactor architecture.
Find cheaper alternatives to per-slot LM5069 hot-swap controllers for 12V daughterboard slots that may draw roughly 16–20A but are not intended for live insertion.
Conclusion
Per-slot hot-swap ICs are not necessary for Rev A if modules are installed only while power is off. The preferred Rev A approach is:
Replace per-slot hot-swap with a per-slot replaceable fuse plus MCU-controlled MOSFET enable.
This provides low-cost fault isolation and firmware control without paying for full live-insertion control on every slot.
Recommended Architecture
Diagram
Option A — Replaceable Blade Fuse Per Slot
Best fit for cheap, high-current, non-hot-plug Rev A protection.
Table
Candidate
Flux UID
Notes
XFCN XF-508P-B-B
06787c13-d794-49d1-aecd-79bd19d1fe28
Automotive blade fuse holder, through-hole, listed for 15–30A, LCSC/HQOnline available. Best low-cost fit.
Littelfuse 178.6764.0001
9adb1693-e998-4135-ae24-ae53fad7277f
MINI blade fuse holder, up to 30A max / ~22A continuous, 58VDC, better-known vendor.
Recommended first choice: XF-508P-B-B or Littelfuse 178.6764.0001 with a field-replaceable automotive blade fuse.
Option B — Integrated eFuse / High-Side Switch
Search did not find a good JLCPCB/LCSC library match for a true 12V, 15–20A integrated eFuse/high-side switch with EN and FLT.
Closest results were lower-current fuses/PTCs or eFuses and are not appropriate for a full-power 180W slot without derating or paralleling.
Option C — MOSFET Enable Stage
A low-cost MOSFET stage can provide firmware enable/disable. It does not replace the fuse for short-circuit protection unless combined with current limiting.
Gate Driver Candidates
Table
Candidate
Flux UID
Notes
ZXGD3001E6TA
d1d70aad-f2c7-6305-19df-3ec4693ce8db
Diodes Inc. MOSFET gate driver, SOT-23-6, high peak drive. Check high-side topology suitability.
TC4427EOA
97a85c2a-7a6a-4f46-9f44-bf527b597a7e
Microchip dual MOSFET driver, LCSC C636891, JLCPCB Extended, SOIC-8. Good low-side/driver building block.
1EDN7550BXTSA1
5174ac7f-6b62-54cb-c7db-7cf0ebfbc0fd
Infineon non-inverting MOSFET driver, SOT-23-6, high drive strength.
Important: many cheap gate drivers are ground-referenced. A true high-side N-MOSFET switch needs a high-side/charge-pump driver or P-channel/high-side topology. If low-side switching is used, it disturbs ground and is not preferred for these boost modules.
Vishay 30V low-RDS(on) PowerPAK 1212-8, stronger electrically but no LCSC availability shown.
PSMN2R0-40YLBX
57a71abb-ae6a-4670-8e91-a6557f7d9fe3
Nexperia 40V LFPAK56, strong 12V/20A candidate; distributor availability shown but not LCSC in result.
Recommendation for Rev A
Use an upstream input protection/hot-swap/inrush solution for the PSU input.
Use one replaceable blade fuse per slot for hard fault isolation.
Use a MOSFET-based high-side enable per slot if firmware enable is required.
Keep current monitoring on the daughterboard using the two INA181 approach.
Do not pay for a full per-slot hot-swap controller unless live module insertion becomes a real requirement.
Open Engineering Checks
Select blade fuse current rating and trip curve. A 20A fuse may nuisance-blow near full 180W continuous depending on boost efficiency, inrush, ambient temperature, and fuse family.
Confirm fuse holder thermal rise at 16–20A continuous in enclosed ABS chassis.
Choose high-side MOSFET/driver topology that does not lift daughterboard ground.
Add a firmware interlock: only enable a slot after module-present is detected and rail voltage is valid.