Powerboost500 + lipo powering cheapo arduino mini + 3.5" tft. Suggestions?

The overall project is to create a "smart" name tag. I'll most likely solder the adafruit powerboost 500 (PowerBoost 500 Charger - Rechargeable 5V Lipo USB Boost @ 500mA+ : ID 1944 : $14.95 : Adafruit Industries, Unique & fun DIY electronics and kits supplies 500-~1300 mA), the cheap $8 inland arduino pro mini (http://www.microcenter.com/product/431996/Arduino_Pro_Mini_Board) with a maximum overall current output 150/200 mA (unclear), and a 3.5" tft (http://www.adafruit.com/products/2050 unknown current draw, maybe 150mA) together on a perfboard connected by solder bridges. I'll have a shirt pocket that I'll store the battery in. Do you think the cheapo pro mini will be able to supply enough current to power the tft through its 5V rail without dying or should I put the tft parallel with it instead? Also, if my event will go on for more than four hours, should I use a 4400 mAh battery since the powerboost will draw 500mA (if I'm reading the current draw correctly)?

Thanks!

Jesus, $8 for a pro mini? What's it made of, gold?! They're like $2 and change shipped on ebay.

Off the 5v rail? You're totally fine - your power supply is rated for 500mA.

There are much lower limits on current through an IO pin (40mA max, recommended 20mA ), and total for the whole chip. But you're not going through the chip.

If you were powering it off a higher voltage on the RAW pin, and using the onboard regulator, then the current limit would be lower, since you'd be limited by the regulator.

DrAzzy:
Jesus, $8 for a pro mini? What's it made of, gold?! They're like $2 and change shipped on ebay.

Off the 5v rail? You're totally fine - your power supply is rated for 500mA.

There are much lower limits on current through an IO pin (40mA max, recommended 20mA ), and total for the whole chip. But you're not going through the chip.

If you were powering it off a higher voltage on the RAW pin, and using the onboard regulator, then the current limit would be lower, since you'd be limited by the regulator.

The part was actually on sale for 4 bucks but it's at the store that I regularly go to. 2 bucks for convenience isn't bad!

What I meant was the 5V output of the mini, since I'm assuming the RAW pin is where I'd put my input from the boost converter. Or am I wrong in assuming that? Would I just solder the input to one of the 5V pins and output to the tft from the other 5V pin without a problem going over 200 mA?

If you put 5v on RAW, you will not get 5V out. You'll get 3.something.

RAW goes through the regulator, which has a non-zero dropout voltage, so you'd need like 6.something volts (depending on the exact model of regulator they used) in to get 5v out. But since your booster already gives you regulated 5v, you can just connect it to Vcc, and take the regulator out of the circuit.

If you're using a higher input voltage, you'd use RAW, and it would be subject to a lower maximum current due to the regulator.

Ok thanks! I’m guessing the 200mA output is for the regulator and atmega so I’d be fine running close to a little more than that through the 5V?