Can anyone recommend a BUCK/BOOST Controller?

you won't get that from buck-boost. V out = -6.5V is a possibility though.

Bye. Jasen

Thanks for the response.

I did some more reading and decided the Sepic is the best solution.

I'd recommend a separate PWM control IC that goes down to 5 volts input, and external switches. A control IC with an output that drives a low side switch can be used in conjunction w/ a high side driver for the high side switch, which should be an n-channel. A buck-boost incurs 2 forward drops due to the 2 diodes. At 6.5 volts, the 2 diodes, which should be Schottky, will limit efficiency. Still, a non- inverting buck-boost (positive output from positive input) should work well.

A SEPIC also does the job, and it has but 1 diode drop. With a low output voltage like 6.5 volts, this is advantageous in terms of efficiency. The SEPIC however has less bandwidth than the buck-boost when operated in continuous conduction mode.

If lowest noise is the goal, then a boost-buck would be the best choice. It has 2 diode drops, and limited speed, but lowest in noise.

I hope I've helped.

Claude

Thanks Claude

I'm going to try a DCM sepic with a TPS40210. I wanted to use a UCC2803 but they are to pricey.