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Topic: Trouble with a boost converter (Read 2 times) previous topic - next topic

winner10920

Perhaps a very large capacito can provide you the 1amp startup current, idk how large since it depends on how long it needs it

mauried

Only boost or inverting converters initially draw large amounts of current to start.
Buck converters (reducing voltage) arnt as bad as the switch is in series with the load.
But , any switching converter will have trouble starting when fed from a current limited
source like an Arduino output pin.

Docedison

You could add a PNP transistor and 2 resistors to make the pin switch the main 5V source off and on as required or for that matter and better a P Ch Mosfet would be an even better choice. There are several made by Supertex that are in TO-92 packages and have Rdson values around 2 to 3 ohms require no heat sinking and are easy to use there are a lot of varying types of packages... Siliconix makes a whole family that are SOT-23 size in the same current range and bigger ones in SOT-223 packages as well as a different line of devices in SO-8 packages for still higher > - 5 A Id current loads.

Doc
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aoeud

#28
Aug 04, 2012, 04:29 pm Last Edit: Aug 04, 2012, 04:43 pm by aoeud Reason: 1
Oh you guys are so helpful! <3

Taking a look at all of this, really appreciate the power supply link (the Arduino wiki article was rather lacking.)  Actually, going to read all of your tutorials. :)

It happens that I was planning to eventually use a current closer to 1 amp so this stuff is really good to know.

Love this stuff.

mauried

If all you need to do is turn the converter on and off, the connect the Arduino output to pin 3 which is the shutdown control.
Converter runs when this pin is grounded, stops when this pin is high.
Connect the switcher chip Vcc to a decent 5v supply.

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