Stevo

Recreate the Arduino Powered PWM

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I am by no means a professional EE, so if you see anything here that is not up to standards (and you see what I'm doing wrong) please feel free to tell me.

I don't sell these things and I don't intend to.
If you want to try and reproduce my setup, I can help you with that.

Highlights
  • The easiest MOSFETS to use are going to be the Fairchild FQP30N06L https://www.sparkfun.com/products/10213. This is a good tutorial on how to implement these switches using Arduino: http://bildr.org/2012/03/rfp30n06le-arduino/
  • I use a 10K pull down resistor and 1N4004 (similar to the tutorial) for the gate-to-source connection.
  • The PWM library I use is: https://code.google.com/p/arduino-pw...3.zip&can=2&q= which allows me to roughly tune the frequency to 16.5K (the correct frequency for my build NOT some magic number) and still get a reasonable working resolution.
  • I am using Cat6 cable from the Arduino Nano to the power slave box gate terminals which is fine if you stick with the FQP30N06L MOSFETS.
  • I am a father of 3 and VERY busy all the time, so please understand I may not be able to respond immediately


Side note: I also started building another higher power unit using two of these bad boys: IRFP064N http://www.irf.com/product-info/data...a/irfp064n.pdf. I quickly realized that I needed to use a "charge pump" to get the thing to turn on completely at 100% duty cycle.
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  1. Stevo's Avatar


    Notes:
    • U1 - 7805 5V Positive Voltage Regulator
    • PAD OUT - 5V supply to Arduino
    • PAD IN - 5V signal to MOSFET gate
    • Used 4N35 optocoupler to handle 5V signal above
    • C0 & C1 - 5V voltage stabilization
    • P0 - Source (from ground)
    • P1 - Drain (to reactor)
  2. Stevo's Avatar
    http://bildr.org/2012/03/rfp30n06le-arduino/ This tutorial, the one I originally referenced, has the gate connected directly to D3 which for an Uno is a max 40 mA. As a general rule of thumb, you would allow no higher than 25 mA if connecting the MOSFET this way.

    I chose to go a slightly different route and protect my Arduino using a 4N35 optocoupler (http://measure.feld.cvut.cz/groups/edu/osv/4n35.pdf) and use a standard 7805 5V positive voltage regulator to supply the gate voltage. Here is how to setup the 7805: http://arduino.cc/en/Main/Standalone. It is the basic stand-alone setup for breadboards. You end up with a stable 5V supply.






    For the 4N35 I use a 330 ohm resistor on the Arduino side to limit current to ~15 mA.