Abdul,

I'll have to look up a TL494. I'm not familiar with it.

(Steve,)

I checked out Maxim. Their Max727, Max787, Max724 are candidates. They support upto 40Vdc in. Input might be boosted with a JFet input stage but I'd rather leave that to an analog contractor I hire for these issues.

I'm currently reading about the Max5003. Its got interesting possibilities, certainly more chip than we require but very robust.

I sent an email to the Maxim design support group and the guy that responded didn't appear to know of the four chips I listed above. He told me 30vdc was as high as they go; he failed to impress me.

I'm going to contact Linear Devices and see what they can offer. It doesn't appear to be a topic that many have experienced in this forum.

-Jay C. Box