Timeline for Op Amp Voltage and Current Output
Current License: CC BY-SA 3.0
8 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Nov 29, 2016 at 21:48 | vote | accept | MerpTheAwesome | ||
| Nov 29, 2016 at 20:11 | comment | added | glen_geek | @MerpTheAwesome recommendations not allowed here. Please learn to use suppliers (digikey, mouser, TI, Maxim etc.) parametric part search, keyword "op-amp". Yes, some exist, but they'll overheat at higher current, and many will eat a portion of solarcell available current. All over $8. | |
| Nov 29, 2016 at 19:11 | comment | added | MerpTheAwesome | Sorry for the load of questions, but is there a rail-to-rail power op amp with a voltage drop of 50mV or less? I'm thinking of going with a Schottky diode for a 0.3V drop, so I'm wondering if I can keep the voltage above the battery voltage, 5.6V. | |
| Nov 29, 2016 at 18:31 | comment | added | glen_geek | @MerpTheAwesome small op-amps (like LM741) won't pass more than 25 mA, so that limits charging current - you can't force more current. Power op-amps are rare & $$. Yes, a diode prevents discharge, but adds about 0.7 volt to the op-amp's voltage drop. | |
| Nov 29, 2016 at 18:20 | comment | added | MerpTheAwesome | If I'm putting 200mA through will the voltage drop be the same? Also, if I put a diode on the output line, will it limit battery discharge back into the circuit? | |
| Nov 29, 2016 at 17:36 | comment | added | glen_geek | @MerpTheAwesome "normal op-amps" might drop 2v, and that's with less than 10 mA output current. Rail-to-rail improves the drop to perhaps 0.2v - learn to read data sheets. When your reference voltage drops below battery voltage, your op-amp (comparator) output pulls down toward ground, discharging the battery. | |
| Nov 29, 2016 at 16:30 | comment | added | MerpTheAwesome | Thank you so much! I know that battery charging is highly complex, but I'm trying to be able to produce this circuit for a low cost, so I watered it down to an overcharge prevention. Since there is a voltage drop, how large is it? With the normal op amps and rail-to-rail op amps? Also, how will the op amp discharge to battery if it drops the reference voltage? | |
| Nov 29, 2016 at 15:54 | history | answered | glen_geek | CC BY-SA 3.0 |