Do we have any 555 experts on here?
I am feeding the control voltage into pin 5
and the duty cycle seems to be limited to 0% to 50%.
Over 50% and the pulse width jumps to max.
-- 
Paul Lamar ...No rotor no motor.

   Paul

Check your input signal carefully to ensure it is not going more negative
than gnd. This can forward bias the substrate junctions. Also input pulse
width at the upper threshold level must be shorter than the output pulse.

regards, Robert


Thanks Robert. I did that. Did not help. I have some TI TLC555IP CMOS 555 on order
from Digikey. In my experience CMOS are less prone to glitches.

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Bingo!!! The 79 cent  TI TLC555IP CMOS 555 is the hot tip.
A bonus for a CMOS chip is it's high output drive current of
15 ma source and 150 ma sink. It is not your grandfather's 555 or even
your dad's for that matter. That should be enough to drive the injector FET
directly.

The control voltage is perfectly linear from 1 volt to 9 volts 1 ms to 9 ms.
which is exactly the range we need. Perfect!!!!!

Next step is getting it to work with Bob's op amp
and we will have a two buck 555 fuel injection system :)

Just about any  0 to 5 volt mass airflow sensor will work.

To be continued after OSH.

Paul Lamar ...No rotor no motor.

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