ELE Times December 2016 Electronics News in India | Online Electronics Mag | Page 26

Cover Story

Synchronous

Low EMI LED Driver

Features Integrated Switches and Internal PWM Dimming
Keith Szolusha , Applications Engineering Section Leader , Power Products , Linear Technology Kyle Lawrence , Associate Applications Engineer , Power Products , Linear Technology
The breadth of LED applications has grown to encompass
emissions . The integrated synchronous switches are run with
everything from general lighting to automotive , industrial and test
controlled switching edges that do not ring — offering just the
equipment , sign boards and safety equipment . As a result , the
right balance of high efficiency and low noise — and can be run at
breadth of design requirements for LED drivers has expanded .
up to 2.5MHz , resulting in compact solutions .
The latest LED solutions require drivers that are compact , efficient , low noise , and feature high dimming ratios and advanced fault protection . The LT3922 easily meets these demands .
The LT3922 with integrated switches and internal PWM dimming
Choice of Topologies : Boost , Buck mode , Boost-buck
LED strings are driven by a controlled current that does not need
+
− to be returned directly to ground . Both LED and LED , or either one , can be attached to non-ground potentials . This opens up the field of options for floating output DC / DC LED driver topologies , including buck mode ( step-down ) and boost-buck ( step-up and
The LT3922 36V , synchronous LED driver with integrated 2A
step-down ). The LT3922 ’ s high side PWMTG driver and
switches can be configured as a boost , buck or boost-buck LED
synchronous switches can be configured as a boost , buck mode or
driver . Its high efficiency synchronous and integrated power
boost-buck LED driver , while retaining use of all of the ICs
switches fit into a tiny 4mm × 5mm QFN package . This device
features — namely , internal PWM dimming , SSFM , low EMI ,
integrates Linear ’ s most advanced switching technologies ,
ISMON output current monitor , and output fault protection carry
condensing high power capability into tight spaces while
over from the standard boost topology to the buck mode and
controlling the edge rates and mitigating unwanted field
boost-buck .
ELE Times | 26 | December, 2016