Is this MOSFET driver circuit ok?

[MagicSmoker]

It's a very robust design.  It's one of the standard ways to drive an injector.
A protected driver is not just a MOSFET, it has additional functions. You wouldn't expect to substitute a simple MOSFET in its place.

The trend is toward using larger chips with multiple drivers and integrated diagnostics, such as the TLE8888 or L9788.  They all use similar clamped drivers.  You don't see 1990s-style discrete solutions.

Or like the BTS5231, a smart high side switch for automotive applications which was available for all of 3 years before Infineon abruptly discontinued it. That's the game you play when you rely on specialized ICs rather than "1990s-style discrete solutions."

Besides, the OP doesn't appear to be making a fuel injection system - rather, using a single fuel injector for some other purpose - and it's safe to say he isn't doing this on behalf of an automotive OEM. THAT is why I steered him towards a more conventional approach.

[DBecker]

It's a very robust design.  It's one of the standard ways to drive an injector.
A protected driver is not just a MOSFET, it has additional functions. You wouldn't expect to substitute a simple MOSFET in its place.

The trend is toward using larger chips with multiple drivers and integrated diagnostics, such as the TLE8888 or L9788.  They all use similar clamped drivers.  You don't see 1990s-style discrete solutions.

Or like the BTS5231, a smart high side switch for automotive applications which was available for all of 3 years before Infineon abruptly discontinued it. That's the game you play when you rely on specialized ICs rather than "1990s-style discrete solutions."

Besides, the OP doesn't appear to be making a fuel injection system - rather, using a single fuel injector for some other purpose - and it's safe to say he isn't doing this on behalf of an automotive OEM. THAT is why I steered him towards a more conventional approach.

The first version of the VND14NV04 is listed as 2004.  Digikey currently has 11,300 in stock.  It's hardly a specialized part with uncertain availability.

[Chriss]

I got the point of the avalanche using mosfet stuff. Now it is cleare for me how bad can that be especially when the mosfet avalanche mode is repetitive used.
That could kill the mosfet very quickly...

Ok.
Would somebody be honest and draw a circuit just with the mosfet, load and the clamping so I can be sure I got all the major point how to do it the right way.

Thank you.
My best regards.

[DBecker]

Delete D1, the optocoupler and R2.
Use a VND14NV04 (or similar protected driver) in place of Q1.
Change R3 to about 1 Kohms. It now serves the input resistor.

You likely will initially bench test with no diagnostic feedback.
Implementing diagnostic feedback is best done just before or during turn-off.
The obvious way to implement diagnostic feed back is using an input pin to monitor the input of the driver.  If you are outputting a high level, the input should be high.  If it's low, the input is being pulled down by the protection circuitry.

Alternatively you can monitor that without using an additional pin.  Change the pin from output high to input with pull-up and immediately read back the pin level.  If it's still high, then the driver is operating normally with the internal protection circuitry being supplied their 100uA draw through the ATTiny pull-up resistors of about 25 KOhms.  If it's low, the protection circuitry has pulled the input low and the 1K series resistor is dominant over the internal pull-up and circuit capacitance.

You might consider the LED2 activity indicator circuit.  LEDs are generally robust with reverse voltage well over their rating (typically only 5V).  Some circuits expose them to 120VAC through just a high value resistor.  But to meet datasheet specs you'll want a diode in series.  For automotive use you would want to move it to the 5V rail for consistent brightness, but for bench testing the 12V supply is OK.  I suggest that you increase the resistance substantially if you are going to be using 12V.