F405 & F411 versions of the BluePill

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Squonk42
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Re: F405 & F411 versions of the BluePill

Post by Squonk42 » Tue Dec 05, 2017 9:34 pm

It looks like the MOSFET is the wrong way around since the beginning:
Image
From the datasheet, the DMP2160UW pinout is:
DMP2160UW.png
DMP2160UW.png (11.81 KiB) Viewed 261 times
Look at the Due schematic:
https://www.arduino.cc/en/uploads/Main/ ... ematic.pdf
Due Ideal Diode.png
Due Ideal Diode.png (33.31 KiB) Viewed 261 times
And this TI AN:
http://www.ti.com/lit/an/slva139/slva139.pdf
TI Ideal Diode.png
TI Ideal Diode.png (20.25 KiB) Viewed 261 times

racemaniac
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Re: F405 & F411 versions of the BluePill

Post by racemaniac » Wed Dec 06, 2017 6:27 am

oops XD
well, then now is the right time to turn it around XD

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Squonk42
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Re: F405 & F411 versions of the BluePill

Post by Squonk42 » Wed Dec 06, 2017 7:07 am

No problem ;)

Here is a short TODO list:
  • Add teardrops => Check https://github.com/svofski/kicad-teardrops
  • Panelization => Check pcb-panelizer ( http://blog.thisisnotrocketscience.nl/p ... panelizer/)
  • Fix fill area minimum width => Fixed Top & Bottom GND zones minimum width to 6 mils
  • Added some missing GND tracks between thermal pads due to previous change
  • Problem with PCB edges in 3D view => Fixed by @racemaniac
  • USB connector holes are too small => Fixed pads for J5 (micro USB) to be oval instead of round
  • Remove Ref/Value for U3 (STM32) on PCB top => OK
  • Option: Add an IMU somewhere on the bottom PCB size on an SPI or I2C bus to get a fully working flight controller board! i am thinking of an Invensense MPU6000 hooked to an SPI bus in order to get 8ksps performance
  • Option: Add an RGB LED => 0603?
  • Power AP2112 from +5V, not from +3.3V
  • Add ferrite bead between GND and AGND
  • Replace 32kHz crystal by smaller FC-12M, may be required for previous item
  • Option: Add MCP73831 LiPo battery charger (would require an ideal diode like D3/FET2/R6 in the Olimexino ATMega32U4 schematics)
  • Add pad/pin for VBUS for external PA9 VBUS_SENSE feature (USB Host) => Added a series resistor between VBUS and PA9 to avoid short-circuits
  • Adjust solder mask clearance to 0
  • Make VBAT trace thinner
  • Provide footprint for parallel capacitor near SDCard and voltage regulators
  • Fix MOSFET direction => replace by an SS12 Schottky diode
  • Added PWR_FLAG to schematic to remove ERC warnings
  • Replaced NC by real Kicad ones to remove ERC warnings
  • Cleaned up Expansion connector labels in schematic
  • Cleaned up traces for PA13-14 and PC13-15
  • Changed micro USB connector to BSC-Elec U02-BFD3111B0-009
  • Option: add an SPI Flash chip as an alternative to SDCard connector (overlapping footprints)
  • Add optional shunt resistors to route a single bit SPI bus to the SDCard connector for devices without SDIO interface => NOT POSSIBLE, too tight!
All volunteers welcome!
Last edited by Squonk42 on Tue Dec 26, 2017 9:16 pm, edited 10 times in total.

racemaniac
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Re: F405 & F411 versions of the BluePill

Post by racemaniac » Wed Dec 06, 2017 7:46 am

ugh, can someone explain to me why the mosfet is the wrong way around? XD
i thought of it as a high side switch that is always on, and from what i can see the load (+5V in our case) would then be on its drain, as we originally drew. but that is not correct?
it drives me crazy when googling i can't find clear answers for something as basic as this XD

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Squonk42
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Re: F405 & F411 versions of the BluePill

Post by Squonk42 » Wed Dec 06, 2017 7:58 am

Please look at the Arduino Due schematic and TI AN above.

racemaniac
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Re: F405 & F411 versions of the BluePill

Post by racemaniac » Wed Dec 06, 2017 8:22 am

Squonk42 wrote:
Wed Dec 06, 2017 7:58 am
Please look at the Arduino Due schematic and TI AN above.
I can see the schematic, but i want to understand why it is so XD
Otherwise i'll keep making the same mistake >_<

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RogerClark
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Re: F405 & F411 versions of the BluePill

Post by RogerClark » Wed Dec 06, 2017 8:38 am

Sorry guys.

What is the purpose of the FET Q1

Which direction is it supposed to prevent. e.g. USB -> 5V pin , or 5V pin to USB

It definitely won't stop 5V pin -> USB because of the internal diode as show in the symbol.

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Squonk42
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Re: F405 & F411 versions of the BluePill

Post by Squonk42 » Wed Dec 06, 2017 9:02 am

Exactly, the idea is to allow USB to power the +5V, but not the opposite direction (we want to control VUSB using the SY6280 USB load switch), so the MOSFET body diode should be USB => +5V, like in the Arduino Due schematic and TI's AN.

racemaniac
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Re: F405 & F411 versions of the BluePill

Post by racemaniac » Wed Dec 06, 2017 9:07 am

Squonk42 wrote:
Wed Dec 06, 2017 9:02 am
Exactly, the idea is to allow USB to power the +5V, but not the opposite direction (we want to control VUSB using the SY6280 USB load switch), so the MOSFET body diode should be USB => +5V, like in the Arduino Due schematic and TI's AN.
but since we're also pulling the gate low, won't it also conduct the other way around anyway?
Is it then maybe this that we want to create:
https://electronics.stackexchange.com/q ... ransistors
but that's then with 3 transistors >_<

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RogerClark
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Re: F405 & F411 versions of the BluePill

Post by RogerClark » Wed Dec 06, 2017 10:25 am

Guys,

I presume we are not simply using a diode on the 5V input, because you don't want the 0.5V drop across the diode ?

AFIK the Maple mini just uses a diode for this.

What else uses the 5V input ? that really requires 5V, and not 3.3V from the regulator.

Even if the diode dropped 0.5V that would still be 4.5V on the input to the regulator, and I thought that would be enough voltage for some regulators to output 3.3V ??

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