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Zen Mod

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now, as all important is explained, time to mull about rail sense

I know for sure that Pa is using something in that manner already in PL products, but him being Pa - solving everything with resistors and zeners as level shifters

Mighty ZM , being chicken , I didn't up to recently even know that resistor can be described as CCS ( even if poor one), and I decided to use helper CCS ( see explanation) in form of ultramumbojumbo5$specialpart

in M2 case - wee see that optodiode is fed with voltage from source resistors, where we have voltage in abundance, even shaving it with series resistor

in SissySIT ( still damn good piece of work, if you ask Mighty Modesty Moi), I did use Hall chips ( tnx, Mighty Indra) ....... slope of voltage given at chip output is (2V5 to 5V)/(0 to 5A) ........ but effectively lower due to all summing and whatnot; didn't tried zeners as level shifters to decrease summing losses, but damn slope must be same , shifted with resistors or with anything else

working, but I maybe didn't knew that I can do better, but I obviously wished that I can do better, regarding Iq and offset stability in rail voltage/temp/time domains

so, if one choose to use ( minimal needed value of) rail resistors as current sense chain, even with 0R11 ( two of 0R22 in parallel) we have better effective voltage slope with current change ; numbers doesn't compute exactly, but from actual circuit, behavior is better than with Hall Chips

now ....... say that current is 1A5 , as in LuDEF

we have 165mV across 0R11 sense resistor......... ( I didn't want bigger value, sue me  ...... later I got that voltage slope is enough with that value ) ..... but optoled needs nominally 1V1 to shine happily ............. so- there is a trick with helper CCS ( again, Pa using resistor there) , which is going to add some voltage to optoled - simple addition of 220R resistor and CCS pulling some current , we got additional 935mV

from there, when you gotta that optoled is shining happy, everything is just matter of more or less voltage through series 0R11

all that nicely transposed to opto in lower rail, so we now have rail resistors, each of them having own optotransistor to pull current trough, optotransistors are summed together

again, cap between two rail resistors, if using any of preceeding solutions with two mosfet gates ( one up, one down) we have symmetrical values of rail resistors, everything behaving nicely and polite and .......... almost boring

(M2 is same boring, regarding that)

so, what was left - put all these puzzle pieces on table and combine them

much greater problem is to choose which one of wast number of permutations is worthy of becoming an amp, than drawing any of them

if I forgot something , blame Pa 

Rail sense.png

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svira dobro, to je bitno
kolko je drugacije i kako - msm, W ce da kaze, kad bude teo

ako bude teo

duze od 3 reci


msm, kako moze da svira anap koji ima isti THD spectra kao SissySIT a munut milijon db down?


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pre 19 časa, Zen Mod reče

slusao pola sata, ugasio i otisao iz radionice

ja vise ne pravim pojacala




pre 43 minuta, Zen Mod reče

damn good piece of work, if you ask Mighty Modesty Moi



pre 29 minuta, chakija reče

kako bre to sviraaa u poredjenju sa Sit-ovima, B2J-ovima i ostalim F-jovima?



Izgleda da je nositelj crnog pojasa u skromnosti dao naslutiti. :preved:
Ma kad god kaze da nesto valja ja vise ne preispitujem. Taj stvarno zna sta valja i zna to napraviti. 

EDIT: Cestitam! I nije proslo puno vremena otkad si pokazao one testne skalamerije do gotovog pojacala. :cheers:

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