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Topic: Optional DC-DC Converter on Shield to provide more current (Read 192 times) previous topic - next topic

MajorMadness

Hi, I'm working on a shield for Due and ran into the problem of not having enough power by useing only the providet power from the Due (many Sensors, TFT, LCD and and and). So I was thinking of providing more current by an extra StepDown Voltage Regulator like TRACO POWER TSR 0.5-2433 or XP POWER  SR05S3V3. I want to connect Vin to Vin of Due or Termal Block an Vout to v3.3 so it's optional to use it. With a 3,2" TFT you might save the money, with 7" TFT you solder it on the shield.

Question is if this is possible or maybe also power the Due with it instead of useing the build in Regulator? I know you can do it with 5V on Uno, but don't want to test it and destroy my Due. ;)

Thx in advance.

MarkT

The Due's supplies are hard wired to the outputs of 3.3V and 1.8V regulators already,
without unsoldering them you can't safely provide power any other way as I understand
it.  You certainly wouldn't want to inject less well regulated power into these busses, those
on-board regulators help protect the chip from noise/transients from outside.
[ I won't respond to messages, use the forum please ]

MajorMadness

Hi, the dc-DC converter i want to usw is a high effective, high accurate power switch and with 500mA or 1A even better then the onboard type.
I didn't found a 1,8v regulator, only the 5v. I was thinking about building it as and optional power source if the onboard is not enough if a TFT and other stuff is connected AMD as a more effective power Switch if Arduino only is connected to external power, not USB. I don't need the 5v onboard, so it would be enough for me to only use the step down buck. I'm just not sure what would happen if connected to USB and external power though step down. To bad there is not shotkey protecting the onboard regulator...

spicetraders

I have a board I just bought it is missing the large black square near the DUE name on the board.
It kills both 5 and 3.3 supplies on the board.
I believe it is L4, I have posted a picture on forum asking for confirmation.

If it is L4 then I may be forced to direct input 5V on the output leg of its pin.

This may be your tie point for a direct 5V in of higher current, but I would wonder what levels of current the traces could take with out failure.


MajorMadness

Apply 5v through the 5v pin wouldn't solve my problem cause I only use 3V3 devices and need to get all voltage out of the linear regulator. As far as I can see it would heat it to mich or even goes over the specs of it. But I don't need the 5v at all, besides programming. So running only with external 3v3 power through that pin would be best for me. I'm just not sure if it would damage the linear regulator on board.

spicetraders

So you need to disable or remove the 3V regulator, shame as the L4 is large and looks easy to remove, but no such choke in the 3V line.

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