Power Architecture Review
take a look at all these components I want to make sure that the RP240 doesn't back power the buck converter and that the power switches to buck converter power when I power through this connector. is the current architecture correct? make a design doc outlining this problem.
Thought for 10 sec
I’ll audit the existing power architecture around the RP2040 Zero, buck converter, and connector power path, then write a project file documenting whether back-powering is prevented and what changes are needed.
Worked for 4 mins 33 sec
I reviewed the power architecture and created Power Backfeed Architecture Review.
Verdict: the current architecture is not correct for preventing RP2040 Zero USB/5 V back-power into the buck output network. The
V5 buck output is directly tied to U1:5V, and the RP2040 Zero’s 5 V/VUSB/VSYS node is directly connected internally, so the fix should split V5 into buck-side and RP2040-side rails with a Schottky/ideal-diode power path; I also flagged Q1 source/drain orientation and C11’s likely net/role mismatch.Recommend ideal diode
Check Q1 orientation
Run ERC/DRC
Propose rail names
Add wiring table
Refine this doc
Ask about this doc
Design Notes
Routing phase status — 2026-05-05
Power Routing Phase
- Inspected power-related nets:
VIN_28V_RAW,VIN_28V_PROTECTED,V5,V3V3_MOTOR,GND,SW,BOOT, andFB. - Re-optimized placement for routing access: power input and trigger terminals are on the left edge, motor terminal is on the right edge, power components are grouped near the lower-left/lower-middle section, and motor driver is near the motor output terminal.
- Configured stackup intent on the existing 4-layer board: layer 2 as Ground Plane and layer 3 as Power Plane.
- Applied power-net trace-width rules:
VIN_28V_RAW,VIN_28V_PROTECTED,V5,V3V3_MOTOR,SW,BOOT, andFBset to 0.4 mm;GNDset to 0.25 mm. - Regenerated neckdown geometry successfully: 1 polygon created, 0 failures.
Verification
- Board remains 70 mm × 45 mm, 4-layer, with all 22 components placed inside the outline.
- Current DRC status: missing footprints, invalid layers, overlapping copper, and floating copper checks pass.
- Remaining blocker: airwires still present, currently 27 reported by DRC. This indicates physical copper traces have not yet been completed for all schematic nets.
Remaining routing sequence
- Complete physical routing for power nets:
VIN_28V_RAW,VIN_28V_PROTECTED,V5,V3V3_MOTOR,GND,SW,BOOT, andFB. - Route motor nets:
MOTOR_A,MOTOR_B, and motor-driver control outputs as needed. - Route control/trigger signals:
TRIG_IN,TRIG_SENSE,MOTOR_FWD,MOTOR_REV, and related GPIO/resistor/indicator connections. - Run final DRC cleanup and verification until airwires and critical manufacturing checks are clear.
Notes
The available automated actions completed placement optimization, stackup setup, net rule assignment, neckdown generation, and DRC verification. Final physical trace routing still requires a full routing pass before production export.
Routing phase status — 2026-05-05
Power Routing Phase
Verification
Remaining routing sequence
Notes
ryanf