LM317AHV - and 48V DC DC convertor
Hi all sorry about this bit i have an issue with the above project, and i am not very good at fault finding yet.
ok the story goes... i have a 48V DC input and need to drop the voltage to around 15v (12V to 25V) the power is comming from a forklift truck and powering a Mobile computer (teklogic 8255)
i have two possible paths i can get a new power suplly rated for the new forklift trucks and much expence or make a little cct to mount inside the computer (in line with the computers power supply).
EG. Power in (48v) > to my cct > mobile computer power supply (12v to 30v it has a big range)...
So i did my research and then made the above prototype. I selected the LM317AHV as this seems to have a higher input voltage tolerance then the normal LM317T.
The above cct seemed to work for a few seconds then fail so i guess its the LM317 that has gone. But why? that is the puzzle.
i have also provided the cct schmatic that i have designed. (very typical just the Resisters have been changed from the referance design in the datasheet).
Do i need the output Cap when testing the cct?
Does the cct need to have a Load to make it work correclty?
How do i correect the design so that the LM317 does not fail?
I know this is a big ask as with out the pcb its very hard just a few pointers or anything i have done which is obviouls faulty.