Dear sir,
we have a regular problem with our embedded controllers in our high power welding controls. Ie the welder capacity is around 200KVA across 440v AC line. [across 2 phase of the three phase 415v line] Occasionally either when we start welding or when welding is beeing terminated, we get an uncontrolled pulse from the controller. After repeated checkups we found that the input tothe Linear regulator LM7805 either to be going to a voltage less than 8v are more than 18v where in the output from the 7805 was carrying lot of jitter.
As an experiment we put a dcdc converter got from RS componentsin replacement to LM7805 and found the performance improved. we decided to fix a custom made dcdc converter in all the existing instruments, as well as in all our future supplies. request support us with an isolated dcdc converter sch for an input voltage of 8v 18v input and output of 5v @ 500mA. The circuit should be a very compact design. any flexibility if required on the input of dcdc can be changed from our side.
regards
padmanabhan.k