OK.
You kill R6, R7, R8, Q8. You change C1 to 1n and connect from collector to base. You make R5 10R, Q4 BD140 (Q4 BJT surely having already). Q6 2N5457 you change to 2SK170 (there is no more than Vbe for it now and 2SK has low enough -Vt).
You keep R3 & Q1 if you got Mosfet CCS right now, it gives PSRR much better than using a BD140 there too. If by any chance you use a BJT CCS Q1, R3 must be 10R.
No, I didn't modified it, it's from the page 190, the one that Salas posted.
Thank you Salas, all is clear, I will do it in a couple of days, will post back with results. Q1 is Mosfet (IRFP9240), so no changes there.
Thanks,
Fedor
is R10=27k.
There is 3.3V at it's +ve end and 0.6V at it's -ve end.
That 27k passes ~0.1mA.
The jFET CCS (Q5) is starved.
Even 1k0 will only pass 2.7mA. A Lowest Idss of GR grade might just work, but there is little spare current to supply the demands of the base pin of the BJT
The sk170 would all (Q5 & Q6) perform a little better if they are low in Idss at these very low voltages.
Might even be worth moving to the GR grade.
There is 3.3V at it's +ve end and 0.6V at it's -ve end.
That 27k passes ~0.1mA.
The jFET CCS (Q5) is starved.
Even 1k0 will only pass 2.7mA. A Lowest Idss of GR grade might just work, but there is little spare current to supply the demands of the base pin of the BJT
The sk170 would all (Q5 & Q6) perform a little better if they are low in Idss at these very low voltages.
Might even be worth moving to the GR grade.
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Salas, can you specify what should be changed, please? I'm kind of newbie in this field
Do I need to change R10 from 15K (you've suggested to use it instead of 27k for 5v version) to something small, and because of this, value of C2 will change also? And if using LED and diode, where should they go?Andrew, so it's better to change to GR grade of SK170 for 3.3V version? Right now they are all BL grade.
Thanks,
Fedor
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