XPost: sci.electronics.components, sci.electronics.design   
   From: stereobuff07@gmail.com   
      
   "DaveC"  wrote in message   
   news:0001HW.1ACE4770000682DB110E6A3CF@news.eternal-september.org...   
      
   I have a FET and a load and a micro outputting PWM.   
      
      
   I want to convert the PWM to DC (low-pass filtered?) which will control the   
   current through the FET.   
      
   I also want to be able to calibrate the DC voltage such that for any given   
   PWM duty-cycle I want to be able to adjust the resulting DC voltage plus or   
   minus a yet-to-be-determined percentage. This will probably need to be done   
   only once so a trim pot will be fine.   
      
   I’m guessing this calls for a “driver” transistor to drive the FET? Or   
   an op-amp? Both?   
      
   Open to any suggestions.   
      
   Oh-so-helpful chicken scratch here:   
      
   http://i.imgur.com/ZXlsmtN.jpg   
      
   FET is IRFM150.   
      
   Thanks for your help!   
      
   The filtered DC voltage from a PWM source can easily me calculated.  If you   
   know the Duty Cycle and the voltage used to produce the PWM signal, it's   
   simple math.   
      
   Shaun   
      
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