Note that TI's LM5118 is a 75V dual mode regulator. 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. This regulator’s control method is based upon current mode control utilizing an emulated current ramp. Emulated current mode control reduces the noise sensitivity of the pulse-width modulation circuit, allowing reliable control of the very small duty cycles necessary in high input voltage applications.