Until now, my favourite Synchronous Buck-Boost DC-DC switcher has been the ever so prevalent Linear Technology LTC3780 - High Efficiency, Synchronous, 4-Switch Buck-Boost Controller. Cheap, fully assembled PCBs can be found on amazon and ebay.
This, no frills part operated comfortably in the 4 to 36V range and had no current limiting or Undervoltage Lockout (UVLO) on-chip.
LTC8390 - High Efficiency, Synchronous, 4-Switch Buck-Boost Controller
This design is based on a LT8390 that has a wider operating voltage range, 4 to 60V, attracting my interest as I've always wanted to be able to support 48V systems.
In addition to the wider operating range, it also has an accurate Undervoltage Lockout with hysteresis, perfect for battery systems. It also includes output current limiting and Spread Spectrum Frequency Modulation for Low EMI.
If you are needing a constant current LED driver, just change a handful of parts and swap the LT8390 to the almost identical pinout LT8391 60V Synchronous 4-Switch Buck-Boost LED Controller with Spread Spectrum.
This board has been designed to fit into a Hammond 1455C802 Enclosure.
C8, C4, C5, C19
C1, C2, C11, C12, C15, C18
Thick Film Resistors - SMD 787K OHM 1%
Q2, Q3, Q1, Q4
C13, C14, C16, C17
R12, R13, R14, R15