6-100V Wide Vin, Current Mode Synchronous Buck Controller

The LM5116 is a synchronous buck

controller intended for step-down regulator applications from a high-voltage or

widely varying input supply. The control method is based upon current mode control

using an emulated current ramp. Current mode control provides inherent line

feed-forward, cycle-by-cycle current limiting, and ease-of-loop compensation. 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 applications.

The operating frequency is

programmable from 50 kHz to 1 MHz. The LM5116 drives external high-side and low-side

NMOS power switches with adaptive dead-time control. A user-selectable diode

emulation mode enables discontinuous mode operation, for improved efficiency at

light load conditions. A low quiescent current shutdown disables the controller and

consumes less than 10 µA of total input current.

Additional features include a

high-voltage bias regulator, automatic switch-over to external bias for improved

efficiency, thermal shutdown, frequency synchronization, cycle-by-cycle current

limit, and adjustable line undervoltage lockout. The device is available in a power

enhanced HTSSOP-20 package featuring an exposed die attach pad to aid thermal

dissipation.

New products (LM5148 and LM5149) offer reduced BOM cost, higher

efficiency, and reduced design size among many other features.