Driving 12V 3.5 Amp Pump with PIC

Discussion in 'The Projects Forum' started by theeld, Oct 5, 2006.

  1. theeld

    Thread Starter Member

    Oct 5, 2006
    Ladies and Gents,
    I am attempting to build some sort of switch that is controlled by an I/O 0-5 V digital pin on a 18series PIC. The PIC im sure can only drive about 15mA of current soooo....

    I am wondering what is the best way to drive a Pump whose input voltage is 12V and draws 3.5Amps. My current idea is to wire the output pin of the pic into the gate of a MOSFET with the Pump connected between the 12V supply and the Drain or the FET, and connect the FET source terminal to ground. Maybe put a protection diode (Schotkey??) across the leads of the Pump to save the transistor when switching.... Will this be sufficient?? the 12V supply is system voltage of an automobile. Are there better ideas, and will a MOSFET be able to handle 3.5 AMPS?? Thanks for looking:)
  2. thingmaker3

    Retired Moderator

    May 16, 2005
    MOSFETs are made which can handle your current. I've blown up some that can handle 20amps. (Not that blowing up is what they were supposed to do...)

    I suggest adding a driver stage between your PIC and the MOSFET. A net search on "MOSFET driver" should help.
  3. Gadget

    Distinguished Member

    Jan 10, 2006
    Or you could use a relay
  4. Søren

    Senior Member

    Sep 2, 2006

    A TIP120 or similar BJT will do nicely as well, just ad a resistor between the base and the output pin.