questions about 5v (115r) COP output regulation

[rossi46numberone]

Hi everybody,
I'm driving my Golf 4 (1.8T 20v)allday long with my 3.7 installed and it work fine...
But for more reliability I would like to change my old style 3 wires COP for the more recent (115r)with 4 wires (5 Volts trigger).
After some some test on the bench I find that I need +5v to trigger it .
My idea is to use a LM7805 to get stable 5v without worrying about the input.
Why?
because the voltage is never the same and if I use simple resistor, the output will follow these fluctuations.
My questions is :
Can I use this regulator in serial with the direct output of the igbt/logic driver or it would be better to work with stepper driver?
I think yes for both of solutions, but your advice will be very helpfull to confirm

Thanks guys  ;)

[GintsK]

Do you also find 12V as not usable for driving these coils?

I think many users drive 4 VAG active coils from stepper output + 1 coil from IGBT Logical level input trough 2x510 Ohm in parallel.

[MWfire]

i always drives that coil from stepper output(12V) with 100-330ohm in series without problems.

[GintsK]

IIRC I had done it directly with no resistors.

[rossi46numberone]

Hi,
Job's done,I 've used two LM7805 and stepper pin 4 & 5 (EC18) and it work nice....

Thanks guys for your advice ;)

Michele.

[rossi46numberone]

I'm back with some bad news  :-\
I've fried one of the LM7805 and it's seems that my stepper driver fail ???
In fact after that issue,I have some hard cut-off(like missfire but stronger) when I connect my laptop with Vemstune open,I feel that the problem happens when the pressure increases and after that the Vemstune disconnected himself and no communication.
If I run my car without connecting the laptop no trouble at all.....
Thing strange is that I can hear these cut-off through my audio speakers,it sounds like an electric parasite.
Now i drive my coils by the logic level trought a 330 ohm resistor and it work great but the problem persist.

Michele.