Quad BLDC Drone ESC Design
Worked for 2 mins 57 sec
Added the ESC-side power input interface:
- J21: Würth REDCUBE M5 lug for
PM_6S_PROTECTED - J22: Würth REDCUBE M5 lug for
GND - J23: 5-pin low-current header for
3V3_Aand GND, with one spare pin marked no-connect
Focused ERC/connectivity check found no new issues for J21–J23.
Define the SPI mezzanine pinout between the ESC and flight controller with spare pins.
Thought for 5 sec
I’ll define a practical SPI mezzanine pinout for the stacked ESC ↔ flight-controller interface with grounds, reset/fault lines, temperature telemetry support, and spare pins, then record it in the project notes/spec.
Worked for 1 min 53 sec
Defined the ESC ↔ flight-controller mezzanine pinout in Project Specification.
Summary:
- 60-pin ERM8/ERF8-style pinout.
- Shared SPI bus with separate CS/INT/FAULT/RESET/READY for STM32 U1 and U2.
- Includes heartbeat, sync, arm/safe lines, 18 ground pins, and 18 spare/reserved pins.
- High-current 6S power stays off the mezzanine connector.
Add mezzanine connector
Assign MCU pins
Run full ERC
Review connector sourcing
Prepare PCB placement
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Ask about this doc
ESC Power and Current Sizing Notes
User-Declared Motor Current
- Maximum motor current: 36 A per motor.
- Four motors total: 144 A aggregate worst-case if all motors hit max simultaneously.
Immediate Design Implications
- Treat 36 A as the power-stage design input until continuous current and burst duration are known.
- Each motor inverter needs MOSFETs, phase copper, connectors, current-limit sense path, and local bulk capacitance sized for at least the 36 A channel maximum with thermal margin.
- The main ESC battery input path and power-management output feeding the ESC must be evaluated for up to 144 A transient aggregate current, unless firmware/current limiting intentionally prevents simultaneous maximum draw.
- A single shared PCB trace is unlikely to be appropriate for the full aggregate current without very wide copper pours, heavy copper, bus bars, or distributed power entry.
Protection and Distribution Notes
- Each downstream board output from the power-management board should have its own surge/current protection path.
- ESC output protection must be sized separately from lower-current flight-controller and E/O camera outputs.
- For the ESC path, protection device choice depends heavily on whether 36 A is continuous, burst, or stall current.
Open Inputs Needed Before Selecting MOSFETs/Connectors/Protection
- Continuous current per motor.
- 36 A burst duration and duty cycle.
- Motor voltage rating, KV, pole count, maximum RPM, and winding resistance if available.
- Cooling assumptions: prop wash airflow, enclosure, copper weight, heatsink allowance.
- Battery pack C-rating and expected maximum pack current.
- Whether firmware should enforce total current limiting across all four channels.
User-Declared Motor Current
Immediate Design Implications
Protection and Distribution Notes
Open Inputs Needed Before Selecting MOSFETs/Connectors/Protection
