Car high current (3A) power supply

Hello!

If you don't want to read the background, you can skip right to the questions!


I have a GM862-GPS module and a ATmega329 microprocessor running (which would draw about 500mA at running time). However the GM862-GPS module can cause peaks up to 2A, so I need a power supply for the car to handle that. :slight_smile:

I have got a few SPX29302 3A adjustable voltage regulators - but I do not know if they will heat the hell up if I just connect it straight to the car's 12-14V and draws 500mA (or at GSM-peaks 2,5A). :astonished: The Telit GM862-GPS hardware guide says to use a switched power supply - I have a lot of MC34063 chips laying around but they can only provide 1,5A at max and they require too many damn components to get working!

My current power supply is designed (very inspired from SparkFun's breakout board) as the following:

The datasheet for the SPX29302 chip can be found here http://www.exar.com/Common/Content/ProductDetails.aspx?ID=300#


So my questions is:

  1. How should I build my power supply? I have read that I should include a protection diode to handle 600V in the GM862 hardware guide - but other places I have found car supplies only secured by a 1N4000 diode - and should I add a 100uF cap to the Vin of my schematic?

  2. Is it okay to place the SPX29302 directly to the (eventually filtered and diode-secured) power supply from the car (12-14V)? If not, can you please give me some hints about a car-schematic that would work.

Thank you very much!

To start with you want a fuse in there,,,