MC3484S2 Injector Driver

[Dale Ulan]

> Both companies are sending samples.  Unfortunately of course, Motorola is
> sending the 4 amp version.  Motorola was extremely friendly and generous
> about the phone call, and National acted like I had pulled them away from
> playing Solitaire.

Sounds about right. I guess only small numbers of people were using the
2.4 amp version. Probably didn't get the attention of the car manufacturers.
> 
> Am I correct in assuming that the MC3483S4 is completely useless with the
> 2.4 ohm injectors?

The S4 is normally used to drive large injectors, such as the Servojet
natural gas injectors, or throttle-body injectors. It'll work if you
parallel two injectors, like some car manufacturers do.

> 
> used with these 'peak and hold' circuits.  I've based that on the coil

Yup. It's just a bit slower when you don't use a peak+hold driver, that's all.

> I have also seem some Bosch injectors from a Chevy V8 that had a 16 ohm coil.
> Are these intended to be driven by full battery voltage?  Did GM use this
> approach to save money on the driver circuitry?

Yes, and probably. They used power MOSFETs and a clamp zener across them.
> 
> used successfully in reverse to get less fuel from a too-big injector?

To a point..., but as you said already...

> Below some magic point, wouldn't that foul up the spray pattern?

Yes

-Dale