I chose TI because they make a number of darlington drivers I have used in the past. But I have never had to drive 2 ohms. _________________ The search for better is endless. Instead simply find very good and get the job done.
Kenny
Joined: 07 Sep 2003 Posts: 173 Location: Australia
Posted: Tue Feb 01, 2005 6:43 pm
Or you could use a 'Logic Level' N channel FET.
I used an Infineon SPP80N03S2L-03 (available from Farnell) with a direct injector (diesel) with a 0.4 ohm solenoid - that's about a 30A pulse with a nominal 12V supply, so the leads have to be short and thick to reduce the voltage drop on them.
For 2 ohm you could use one with a lower current rating.
Also I place a resistor between the pic port pin and the gate of the FET to protect the pic if the FET breaks down. The value is not critical - I used 4k7.
The gate capacitance wasn't a problem, in the experiment the injector was on for a few milliseconds.
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