DC-DC buck converter for charging SLA batteries.
I have a 29VDC supply and need to charge/maintain a "24V" lead-acid battery.
To do this I need a 27.6VDC supply rail that is current-limited to about 750mA.
I don't require isolation. The (-) rail will be common to the input and output.
I really just want to current-limit and voltage-limit the (+) rail.
Because the battery might be severly discharged (or the output leads short-circuited), the output voltage might be significantly <27.6V during current-limited charging, so a linear design might need to dissipate a significant amount of power. (about 20W under worst-case conditions.)
For this reason a switcher seems like the best choice.
It sounds like all the functions found in so many DC-DC switchers you guys have, but it would require a P-channel FET in the switcher instead on an N-channel.
Is there a PI part that could do this with just an inductor? (no transformer)
We need to keep parts cost to a minimum.
-Dave
Why not try some othe part from TI, Maxim. PI is expert at AC/DC with 700V MOSFET.