描述

 

The LM5116WG 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 utilizing 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 LM5116WG 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, frequency synchronization, cycle by cycle current limit and adjustable line under-voltage lockout. The device is available in a CPGA-20 high temperature ceramic package with the thermal shutdown feature disabled.

 

特性

 

Hermetic Package for Harsh Operating Environments

Emulated Peak Current Mode

Wide Operating Range up to 100V

Low IQ Shutdown (< 10 µA)

Drives Standard or Logic Level MOSFETs

Robust 3.5A Peak Gate Drive

Free-Run or Synchronous Operation to 1 MHz

Optional Diode Emulation Mode

Programmable Output from 1.215V to 80V

Precision 1.5% Voltage Reference

Programmable Current Limit

Programmable Soft-Start

Programmable Line Under-Voltage Lockout

Automatic Switch to External Bias Supply

CPGA-20 with No Thermal Shutdown