I would like to make a DC to DC converter that will output something around 12.5-14.4v (think car battery output) and roughly 5-5.2v (USB voltage). Input voltage will range from about 18 - 24v (maybe up to 36). I doubt that I will need more than 10A @ 12v and 5A @ 5.2v. I was thinking that I might be able to parallel 2 LM338's for the 12v rail and a single 338 for the 5v rail. If I remember correctly all I need to do to get the correct output voltage is place the proper resistance/resistor on one of the terminals of the LM338 (appropriate for each voltage needed). I guess I will also have to have some diodes in place to make sure there is no feedback from the 12v to the 5v rail.
The problem is with the varying input voltage. Is there a way to do this so the unit can be used with a
switch to select voltage (or better sense voltage and select proper path)? It seems the most expensive parts
of this design will be the LM338's so if there is a way to use the same ones on for each voltage path that would
be ideal.
The problem is with the varying input voltage. Is there a way to do this so the unit can be used with a
switch to select voltage (or better sense voltage and select proper path)? It seems the most expensive parts
of this design will be the LM338's so if there is a way to use the same ones on for each voltage path that would
be ideal.