Hi built an Lm317 circuit but giving only ma. How can I get 1.5amps out?
Thks
AB

 

Hi built an Lm317 circuit but giving only ma. How can I get 1.5amps out?
Thks
AB

You can’t, without it overheating and shutting down.

Describe your schematic and what you’re doing. A picture is best (of your schematic).

 

Hello,

The output current will depend on the voltage difference on the LM317.
A heasink will be a must for higher currents.
Also when the decoupling capacitors are missing the LM317 will heatup, due to possible oscillations and shutdown.

Bertus

 

Can't help you without a schematic.

 

The LM317 in DPAK or TO220 is capable of 1.5A, but not at high Vin.

There is a limit as to how hot silicon can get inside package, LM317 limit is 125 C.

Design procedure -

http://www.reuk.co.uk/wordpress/electric-circuit/lm317t-heatsinking/

http://www.ef-uk.net/data/heatsinking_JS.htm Tool


Regards, Dana.

 

read datasheet

 

Another trick that provides relief similar to that of lowering the input voltage is to shunt some of the current around the LM317 using resistors. The current through your resistors (between input and output) can be no higher than the minimum load. If your power supply is going to be variable the matter becomes much more complicated.

 

Hello,

An other method to have a larger output current is the use of a PNP pass transistor:



It will work on the LM317 as well as the 78XX series.

Bertus