ECU current draw on startup (filter capacitor?)

[Dean]

Hi!

Not an important issue, but I’m interested to understand.

Fury G4X 

I’ve done a few Link ECU’s with a Hardwire PDM, this is the first one with this issue. The PDM has an ‘instant’ fuse feature if you choose to use it on important outputs. When I use the ‘normal’ fuse setting, it behaves normally and pulls about 0.16A. If I use the instant fuse, the output trips straight away, even with the fuse setting at 10-15A. 

Is the ECU expected to pull quite a bit of current for a very very short amount of time?

 Cheers!

[Adamw]

Here is a quick scope capture of ECU power up at 500us/div.  10V = 1A, so a max of about 0.7A in this case.

 

Zoomed out, that drops back to about 0.2A after about 20ms:

[Dean]

Thanks for that. Good to know.

The data logger in the PDM is only 20hz so I couldn't really see in that much detail!