Datasheet LTC3766 (Analog Devices)

LTC3766 High Efficiency, Secondary-Side Synchronous Forward Controller
FEATURES DESCRIPTION
n
Direct Flux Limit™ Guarantees No Saturation
The LTC®3766 is a PolyPhase-capable secondary-side n
Fast and Accurate Average Current Limit
controller for synchronous forward converters. When used n
Clean Start-Up Into Pre-Biased Output
in conjunction with the LTC3765 active-clamp forward n
Secondary-Side Control for Fast Transient Response
controller and gate driver, the part creates a complete n
Simple, Self-Starting Architecture
isolated power supply that combines the power of multi- n
Synchronous MOSFET Reverse Current Limit
phase operation with the speed of secondary-side control. n
PolyPhase® Operation Eases High-Power Design
The LTC3766 has been designed to simplify the design of n True Remote Sense Differential Amplifier active clamp forward converters. Working in concert with n Remote Sense Reverse Protection the LTC3765, the LTC3766 forms a robust, self-starting n High Voltage Linear Regulator Controller converter that eliminates the need for the separate bias n Internal LDO Powers Gate Drive from VOUT regulator that is commonly used in secondary-side control n Overtemperature/Overvoltage Protection applications. A precision current-limit coupled with clean n Low Profile 4mm × 5mm QFN and Narrow 28-Lead start-up into a pre-biased load make the LTC3766 an excel- SSOP Packages lent choice for high-power battery charger applications.
APPLICATIONS
The LTC3766 provides extensive remote sensing and output n protection features, while Direct Flux Limit guarantees no Isolated 48V Telecommunication Systems n transformer saturation without compromising transient Isolated Battery Chargers n response. A linear regulator controller and internal bypass Automotive and Military Systems n LDO are also provided to simplify the generation of the Industrial, Avionics and Heavy Equipment secondary-side bias voltage. L, LT, LTC, LTM, PolyPhase, Linear Technology and the Linear logo are registered and Direct Flux Limit is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 7200014 and 6144194. Other patents pending.
TYPICAL APPLICATION 36V – 72V to 5V/15A Active Clamp Isolated Forward Converter
1.4µH +V +VOUT IN 6:2 36V TO 72V 5V • • 15A EFFICIENCY: 94% AT 48VIN/15AOUT 2.2µF 220µF 100V FDMS86201 BSC0901NS 6.3V SiR414DP ×3 33nF 100nF ×2 200V 200V 15mΩ 3mΩ 168Ω 0.5W 2W –VIN –VOUT Si3437DV 2.2nF 200k (SOT23) Si3440DV 250VAC 1Ω FG SW SG RUN V + – IN NDRV VCC FS/SYNC VS VS I – 4.42k S 365k NDRV PG I + I – AG I 0.1µF S S SMAG 1.0µF I + S FB RUN IN+ 2:1 PT+ LTC3766 ITH 604Ω • • V LTC3765 PT– CC IN– SS SSFLT FS/UV 4.7µF GND PGND I 470pF PK SGD FGD MODE RCORE DELAY SGND PGND 33nF 26.1k 15k 22.1k 47pF 17.8k 15.0k 33nF 10.5k 14k 18.2k 3766 TA01 3766fc For more information www.linear.com/LTC3766 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Timing Diagram Operation Applications Information Typical Applications Package Description Typical Application Related Parts Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Timing Diagram Operation Applications Information Typical Applications Typical Applications Typical Applications Package Description Revision History Typical Application Related Parts