National Semiconductor is offering its first emulated current-mode-controlled buck-boost DC-DC regulator controller which has an operating voltage range of 3V to 75V. 

The LM5118 features programmable switching frequency up to 500 kHz. The switching regulator features peak efficiency of 95 per cent.

The control method of the LM5118 is based upon current-mode control using an emulated current ramp.

The LM5118 operates as a buck regulator when the input voltage is sufficiently greater than the regulated output voltage and gradually transitions to the buck-boost mode as the input voltage approaches the output. 

This dual-mode approach maintains regulation over a wide range of input voltages with optimal conversion efficiency in the buck mode and a glitch-free output during mode transitions. 

The LM5118 includes drivers for the high-side buck MOSFET and the low-side boost MOSFET.