7.1 Overview

The LM5575-Q1 switching regulator features the functions necessary to implement an efficient high-voltage buck regulator using a minimum of external components. This easy-to-use regulator integrates a 75-V N-Channel buck switch with an output current capability of 1.5 amps. The regulator control method is based on current mode control using an emulated current ramp. Peak current mode control provides inherent line voltage 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, which allows reliable processing of very small duty cycles necessary in high-input voltage applications. The operating frequency is user programmable from 50 kHz to 500 kHz. An oscillator synchronization pin allows multiple LM5575-Q1 regulators to self-synchronize or be synchronized to an external clock. The output voltage can be set as low as 1.225 V. Fault protection features include, current limiting, thermal shutdown, and remote shutdown capability. The device is available in the 16-pin HTSSOP package that features an exposed pad to help thermal dissipation.