> High side FET is underdriven by 220R at other than near DC

High side pull down of 10k is much much too high.
>

Yes I can understand that but as mentioned in my previous response to
Richard I am not concerned with high speeds. But I can reduce these as
required.

N Channel high side gate drive must be above +V by Vgsth + some.
>

The bootstrap circuit works beautifully with a resistive load - I see
almost the full 12V across G and S.


> Add reverse diode across BC847 be junction so driver pills gate down BUT
> then watch gate -ve voltage - zener acting as forward diode will clamp
> this, but slowly.
>

Ok that makes sense.

Overall I'm afraid that this cct needs enough work that copying something
> else that is known working may be easier.
> BUT persist if you wish and we can journey with you.
>

Thank you!
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