Max Volts on PX32A QuickStart board.

wdfreemanjr

It seems that I read somewhere that you the PX32A could handle up to 18V. I would like to power it with 12V on connectors 39 & 40.

Any comments?

Thanks,

JLocke

Don't know where you read that, but that will DEFINITELY let out the magic smoke. Check out the Propeller datasheet before blowing up your chip!

Circuitsoft

@JLocke
Notice, he said QuickStart board.

@wdfreemanjr
The regulator on the QuickStart can take 18V, but it could get pretty warm depending on how much current draw there is. Adding a 7.5V regulator before the board will reduce the power dissipation of the on-board regulator. C12 is limited rated at 16V, and probably shouldn't be driven above 12V to keep a safe overhead.

Tubular

For the SOT223 package the datasheet says 107 degrees C per watt. So if your prop is consuming 80mA you would be dissipating (12-3.3)*.8 or about 0.7 watts, something like a 75 degree C rise. The junction can probably operate up to 125 degrees happily enough. And heatsinking on the quickstart will help out a bit, certainly in the short term. The good news is it has built in thermal shutdown so you shouldn't do any serious damage.

You need to think about what you are driving with the prop. Turning on all the quickstart LEDs for instance will increase the current draw significantly, as will running more cogs. Since you're not going to do too much damage why not hook up a DVM and see what kind of current draw you have with your program as is?

An easy way to make the regulator's life easier is to add some power diode drops in series, or a 5 watt resistor, or a really big 3 watt Luxeon "power on" LED

cheers
tubular