The LM5088 high voltage non-synchronous buck controller features all the necessary functions to implement an efficient high voltage buck converter using a minimum number of external components. The LM5088 can be configured to operate over an ultra-wide input voltage range of 4.5V to 75V. This easy to use controller includes a level shifted gate driver capable of controlling an external N-channel buck switch. The control method is based upon peak current mode control utilizing an emulated current ramp. The use of an emulated control ramp reduces noise sensitivity of the pulse-width modulation circuit, allowing reliable control of very small duty cycles necessary in high input voltage/low output voltage applications. The LM5088 switching frequency is programmable from 50 kHz to 1 MHz.