OK, I will choose TLC277 dual op-amp for CV and CC for now, this one:
http://www.digikey.com/product-detail/en/texas-instruments/TLC277CDR/296-26747-1-ND/2255142What I want to know is how to determine "quality" increase of the op-amp in the design. Or namely how op-amp1 is better quality here than op-amp2? My guess would be the minimum voltage that it can detect and the speed which it runs by - 2.2 MHZ (according to digikey) for the TLC277 I guess, right? although it says 0.3 MHz GWP in datasheet.
I am willing to use 16-bit ADC/DAC (not a very great pricey one, just one that works) so a good op-amp is a must here. I wanna know how to choose one and how to differ between them.
What I came up with is the following choices:
1- LT1678, it is a good high quality choice with somehow reasonable (not really xD) price of 5$. there is the 79 version of 4 op-amps but no need.
2- OPA2180IDR, price is 2.87$.
3- MAX44245ASD+ -> 4$ but has 4 op-amps in it.
I leave this topic for discussion later on, for now we'll get normal opamps.
Now the rest is 2 opamps, one for CV\CC indication and the other is for voltage monitoring. I guess TLC272 can work here for now:
http://www.digikey.com/product-detail/en/texas-instruments/TLC272CDR/296-1310-1-ND/404948or maybe get the 4 opamps version if I need more. If not, then maybe a precision high quality 4 op-amp package can be used for component consolidation.
TL;DR:
For now, TLC277 for CV\CC and TLC272 for the other 2.
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I don't see why we should slow the CC part, if you remember, it was THE problem of the past typologies xD. Thus, adding an extra current limit which acts only when short circuit or violent events happen is the best option. Dunno how to do it now so I will leave it to the rest... down-programmer is the same too.
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I feel very confident now since the major stuff are good enough in this main circuit, the rest is somehow manageable. I will "try" to make a PCB with CM in this laptop, so I hope I will make some progress before getting the new laptop in the last of this month.
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BTW, I made a newer version with these changes:
1- parallel 10uH coupled inductors.
2- changed the shottky diode to MBRB2545CT because it has SMD version (which is important)... circuit functions better now, or maybe I am not seeing correctly.
3- Q2 is now BC807-40 for SMD version.
4- switching frequency is now 300 KHz.
5- due to 4, filtering inductors are 4.7uH again.
6- Q3 is now BC807-40 for the smd version.
drop voltage is now less than 1v (0.94v @20v) due to the change of Q2. Notice that the negative supply of it's base is not precise too so there should be some compensation or just leave it as it is. I picked a divider resistor of 1k with 1.5k due to standard values. the negative isolated supply is not precise too since it doesn't give 9v and -3 exactly.
from now on, anything must be SMD except for what is impossible to get SMD for.