Speeduino is now on Github Sponsors (Rather than Patreon): https://github.com/sponsors/noisymime
For any pieces of hardware directly related to Speeduino (ie Boards, components etc)
By ALG
#31689
I have found that the drive from the teensy adapter board will not drive the 75NS04Z fets . Yes the led's do light but thats a false positive because they only require a few ma. My injectors are 15 ohms and the 75NS devices will only provide around 10ma. I suspect that a high pressure fuel pump would need upwards of an amp. The solution is 3.3v to 5v translators or different fets.
By ALG
#31705
I have the fets on a test board with Vcc 13.6v and a pot connected to the gate to supply ether 3.3v or 5v. The gate threshold on the 75NS04Z is 3.2v so it would be expected that 3.3v of drive would be to low.
User avatar
By PSIG
#31710
ALG wrote:
Thu Jan 31, 2019 11:53 pm
I have the fets on a test board with Vcc 13.6v and a pot connected to the gate to supply ether 3.3v or 5v. The gate threshold on the 75NS04Z is 3.2v so it would be expected that 3.3v of drive would be to low.
True, the STP75NS04Z has a Vgs of 2 to 4 volts, so it may not try to turn on at all under 4V. In-fact, it does not see full turn-on (minimum Rds) until 10V at the gate. If using 3V3 drive, I would suggest using a different MOSFET designed for proper operation at 3V3 gate voltage. Another solution would be to add a proper gate driver to the circuit and keep the STP75NS04Zs.

That said, I would be curious what your drain-source resistance is at 3V3 using the STP75NS04Z ?
:?:
David
By ALG
#31724
Dave,
The rds runs around 400 ohms when driving a 15 ohm load and a vgs of 3.25v with vds at 13.6v. It takes a vgs of around 4.5v to drive a high Z injector to 800ma.
User avatar
By PSIG
#31738
Yeah, that's a fail, as-expected. Back to other options.

David

Yes, 12v was connected, and even with wrong formul[…]

Thank you very much, between today or tomorrow I w[…]

I'm not an expert, but do understand the principle[…]

PCB for BMW m42/m50/m60 engine

;) Have you same information for deka 875cc ? :)

Still can't find what you're looking for?