[Diy_efi] peak-and-hold injector driver ic's

[gngrbrd_man]

I have to disagree here.  Some low impedance injectors have impedances
around 1.2 ohms.  Ohms law would follow that this is a steady state draw of
10A.  Ten amps is way too much to be running through most injector wiring
for very long, much less the injector.
Also, I do know of two sets of these 1.2 ohm injectors that were cooked due
to insufficient current limiting.  Please note that I said 'insufficient',
not absent.  These injectors were being run on Megasquirts with PWM current
limiting, but not turned down low enough.  I will admit that not everyone is
driving 85 pph, 1.2 ohm injectors, but some are, and running them without
current limiting would be foolhardy at best.

Also, the L584 was mentioned in the original post.  it is UNOBTANIUM.
STMicro will only produce to order, minimum 16 week lead time, and 1500
(from memory) part minimum order.  I tried all ST distributors in north
america, and ST themselves.  No samples, nothing.  If anyone can advise me
that this situation has changed in the last 60 days, please do, but....

For the record I also was unable to easily search any circuit details on the
mentioned teletype hammer drives, either google or the first few pages at
the US patent database.  I would love a pointer or two.
Keith

You know you've achieved perfection in design,
not when you have nothing more to add,
but when you have nothing more to take away.
-- Antoine de Saint Exupery


----- Original Message -----
From: <Djfreggens at aol.com>
To: <diy_efi at diy-efi.org>
Sent: Saturday, March 08, 2003 8:13 PM
Subject: Re: [Diy_efi] peak-and-hold injector driver ic's


| my advice would be to stop worrying about current limitng and just
overbuild
| the circut. if you have a peak load of say 1.1amps per injector and are
| firing one injector just go ahead and build the circut with a 4amp driver.
| the injector wont overheat. what the issue is is with driving the gate. if
| your using an oem ecm to drive the gate then just forget about current
| limitng. no real point to it.
|
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