The LM5121 is a synchronous boost controller intended for high-efficiency, high-power
boost regulator applications. The control method is based upon peak current mode control. Current
mode control provides inherent line feed-forward, cycle-by-cycle current
limiting and ease of loop compensation.
The switching frequency is programmable up to 1 MHz. Higher efficiency is achieved using
two robust N-channel MOSFET gate drivers with adaptive dead-time control. A user-selectable diode
emulation mode enables discontinuous mode operation for improved efficiency at light load
The LM5121 provides disconnection switch control which completely disconnects the output
from the input during an output short or a shutdown condition. During start-up sequence, inrush
current is limited by the disconnection switch control.
An internal charge pump allows 100% duty cycle operation of the high-side synchronous
switch (Bypass operation). Additional features include thermal shutdown, frequency synchronization,
hiccup mode current limit and adjustable line undervoltage lockout.