Tuesday, March 9, 2021

ACE-NX inline version - release; build notes

My current ESC I am building, putting into blaster projects, and am shortly to start selling on Etsy.

Gerbers, BOM, SimonK board definition, precompiled FlyShot firmware: https://drive.google.com/drive/folders/1w04lxvGw-rxBViPkGWJeUk-NnfKFg8dD?usp=sharing

Source: http://oshwlab.com/torukmakto4/ace-inx





Overview:

  • ATmega8 or -8A @16MHz with ceramic resonator
  • Infineon 6EDL04N02 gate driver
  • Nexperia 5x6mm LFPAK56 mosfets
  • LDO logic power
  • Boost converter from 5V rail for 12V gate drive supply
  • 40V mosfet options for proper 6S support, plus 30V ultra-low Rds(on) and high avalanche ruggedness/high Idm options for aggressive higher kv motors
  • 26x46mm, 2 layer, 2oz, 10/10mil trace/space (Fab by any vendor)
  • Minimum 0805
  • Enhanced mosfet footprints for easy hand solderability
  • Busbar ready
  • Designed for FlyShot support and use with tach output
  • ICP signal input
  • New board target: ace.hex (see: ace.inc)
  • SimonK-supported status and warning LEDs





There are no silkscreened component designators on my newer boards because they were frequently not resolvable and/or wouldn't fit anywhere with the density, so here's the usual passive placement guides, pay attention to color code:


The green labelled 50-100k resistors are an optional low side gate pulldown. I have been leaving these out - this was my first design with IC gate drivers and I felt the need to include the footprints for them anyway as I do with discrete boards, but they aren't actually required with the driver.

ISP pads with minified labels: RESET, SCK, MISO on the top row, then GND, MOSI, VCC on the second.

Other unlabeled component placements are obvious/unique. More info is in the BOM on mosfet, etc. options.

Errata

Above three low side gate pulldown resistors are superfluous. They also are not actually in the schematic, they were whacked into the PCB at the last moment anyway.

ISP pads are small and annoying, and could use to be bigger.

Caps for decoupling and so forth are overkill. Several 1206 parts could be 0805, and a few cap footprints could probably be Muntzed or combined into one larger value cap without any ill effect.

I don't particularly like the sense trace length and routing on paper, but these handle startups and sync holding just as well as any other board so I doubt there is a noise issue with that.

The 6EDL04N02PRXUMA1 driver is in the midst of a stock shortage and is unavailable a lot of places right now. Stock should be arriving back sometime this month at most vendors, I believe, but I might design future boards with a different driver in the interest of having those plus this one around in case one driver or another is sold out like this again. I already have a supply of them to use for now.

ATmega8 vs. ATmega8A

The exact MCU part to be used in ATmega8-powered SimonK ESCs is an area of ongoing testing. I have only built one pair of ESCs with the mega8 part so far - but I suspect the mega8 part is a better bet for comparator tolerances than the mega8A part.

No comments:

Post a Comment