Page Comparison

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• Background

  • Target use for https://uwarg-docs.atlassian.net/wiki/spaces/ARCHS22/pages/2556133415/Fixed+Wing+2025?search_id=c463239c-2144-46d3-afe5-07fb485223d7

  • Buck converter can be designed smaller than 12S Servo Module because of lower input voltage.

• What

  • Same current limiting circuits as 12S Servo Module

    • 4 Channel

    • Leverage the validation we’re already doing on this PCBA as much as possible

  • Common CAN circuit from ESC CAN Adapter

  • Buck Converter for 6S to 5V

    • Could be copied from Tracking Antenna Nucleo Shield Arch using AOZ2261NQI-12 though maybe higher switching frequency. Test this chip on the previous board if possible, cc Jerry Tian.

  • Keep 30.5x30.5mm mounting pattern from https://uwarg-docs.atlassian.net/wiki/spaces/EL/pages/2189197330/Mounting+Hole+Specifications?search_id=5eb88afa-dccc-4fc7-8c97-c8cc5472042f

    • using 61x30.5mm mounting pattern for ease of routing and to keep all components on one side

  • Current Sense

    • just on the input current would be nice, get some metrics as to how much current the servos require during maneuvers and we already have a CAN line so why not!

  • Target all components on a single side of the PCBA for easier assembly & mounting

• Why

  • 12S Servo Module has some room for optimization for this airframe

    • no CAN support

    • buck converter could be made smaller and lighter since lower max input voltage

• Who

  • Meghan Dang to take this up July 2024 as lead engineer

  • Daniel Puratich guidance and review for architecture & design

• Link

  • https://warg.365.altium.com/designs/7B43FD95-910B-4734-8E93-0F4806D2D4FE#design

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System Block Diagram

Power Block Diagram

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• Supports 18V~28V for 6S battery (rough calcs, 3V-4.6V max per cell)

• 3x4 header inputs & outputs

  • Input:

    • CAN, GND from PIxhawk (creating own 5V PWR)

  • Ouput:

    • PWM, PWR, GND

• 30.5mmx30.5mm board to comply with Mounting Hole Specifications

Components

notes:

• input cmc ← perhaps not needed, check 12s doc to read why they implemented

• current sense

  • use INA180 unless determined otherwise

  • shunt resistor: calculate for it? to be looked up

• buck converter

  • check if existing solves, check for board space

  • if not, make buck with lower input voltage & smaller inductor to maximize board space

• LDO

  • does current one from can circuit solve? if not look for other one

  • purpose is to reduce noise from buck.. consult esc can doc for details

• diode

  • what kind of diode… to be looked up

• current limiting eFuse

  • current ones probably solve, however finding a singular IC with 4 channels instead could be better → maximizes board space

  • try and do some component selection here; will probably ask more questions

  • determine whether 4channel efuse vs 4 individuals will be better

    • things to consider:

      • cost

      • board space

      • power dissipation probs not super critical

      • if 4 channels exist for this purpose

• thermistor

  • not sure how to select one, will see later, not super high priority

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