AN2815 Datasheet, PDF (1/42 Pages) STMicroelectronics – High-efficiency step-down controller

AN2815
Application note
High-efficiency step-down controller
with embedded 2 A LDO regulator
Introduction
The PM6675AS device consists of a single, high-efficiency step-down controller and an
independent low dropout (LDO) linear regulator.
The constant on-time (COT) architecture assures fast transient response supporting both
electrolytic and ceramic output capacitors. An embedded integrator control loop
compensates the DC voltage error due to the output ripple.
Selectable low-consumption mode allows the highest efficiency over a wide range of load
conditions. The low-noise mode sets the minimum switching frequency to 33 kHz for audio-
sensitive applications. The LDO linear regulator can sink and source up to 2 Apk. Two fixed
current limits (±1 A and ±2 A) can be chosen.
An active soft-end is independently performed on both the switching and the linear
regulators outputs when disabled.
Figure 1. PM6675AS demonstration board
!-V
August 2008
Rev 1
1/42
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