LM1949 drivers

[Chris Morriss]

In message <Pine.A32.3.95.970306180856.39051B-100000 at goodall.u.washingto
n.edu>, "S. Lastuka" <kicker at u.washington.edu> writes
>We are on an SAE team designing an electronic fuel injection system.  We
>have completed the design and have a robust system using a Motorola 68hc11
>MCU to generate the injector pulses.  We are feeding the injector pulses
>into a National Semiconductor LM1949 injector driver.  
>Everything seems to work, ie the injectors click on and off, but on the
>oscilloscope we notice that the injectors are only taking about .9 Amps
>peak and a quarter of that on hold.  We have 2 amp peak, .5 Amp hold
>injectors from Seimans.  
>We then hooked up a 15 volt power supply directly to the injectors to see
>how much current they used with straight uncontrolled power and noticed
>that they still only had .9 Amps across them.  The same results were
>reached with two different injectors.    
>We were wondering if anyone has experience with Seimans injectors in a
>diy efi system and if there is a way to get more current through them, so
>they "peak" faster.  Thank you,
>Sean
>
>ps we're running them dry right now for test purposes, I don't know if
>that makes a difference. 
>
These will be early generation high impedance injectors.  They are
designed to run without any currnt limiting from the +12V.
Low impedance generators require current limiting and are only about 2.5
Ohms.
-- 
Chris Morriss