Increasing Current on my voltage regulator

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ObedMiramontes1

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I designed a voltage regulator with that regulates 19 volts and outputs 13.5volts.
I did this by using a 5.1 Zener diode and TL081 op-amp and a npn BJT... I connected the zener diode to the op-amp and by calculating the resistor values adjusted the gain of the op-amp to get my output of 13.5. The thing is that i need more current out of the regulator... so far, i only got a few milliamps and i need at least 1.5A...

Any ideas?

This voltage regulator is going to be connected to a charge regulator to charge a 12 Volt 20Ah battery!
 

Check the data sheet for the PB137 device from ST. It will do the whole job, handling the current and it has overload protection, all in one 3-pin component.

Other than that, you need to further amplify the output current with a second transistor. Without seeing your schematic it's difficult to show the best way of doing it.

Brian.
 
For those who are helping me, this is the schematic i have put together so far!

Thanks!

---------- Post added at 18:57 ---------- Previous post was at 18:56 ----------
 

I’d suggest some initial changes .. see attached drawing ..
Make sure that Q8 is a power transistor, and that V3 is a voltage source of 19Vdc ..
To fine-tune the output voltage you may add a variable resistor in series with R2 ..

Also, you will need to add some caps here and there, for example on the output and the 19V-rail, to make sure that the circuit is stable ..

IanP
:wink:
 

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