U U
LT1681
Dual Transistor Synchronous Forward Controller
FEATURES
s High Voltage: Operation Up to 72V s Synchronizab...
U U
LT1681
Dual Transistor Synchronous Forward Controller
FEATURES
s High
Voltage: Operation Up to 72V s Synchronizable Operating Frequency and Output
Switch Phase for Multiple Controller Systems s Fixed Frequency Operation to 350kHz s Adaptive and Adjustable Blanking s Synchronous Rectifier Driver s Local 1%
Voltage Reference s Under
voltage Lockout Protection with Hysteresis s Input Over
voltage Protection s Programmable Start Inhibit s Transformer Primary Saturation Protection s Optocoupler Feedback Support s Soft-Start Control
U APPLICATIO S
s Isolated Telecommunication Systems s Personal Computers and Peripherals s Lead Acid Battery Backup Systems s Automotive and Heavy Equipment
DESCRIPTIO
The LT®1681 controller simplifies the design of high power synchronous dual transistor forward DC/DC converters. The part employs fixed frequency current mode control and supports both isolated and nonisolated topologies. The IC drives external N-channel power
MOSFETs and operates with input
voltages up to 72V.
The LT1681’s operating frequency is programmable and can be synchronized up to 350kHz. Switch phase is also controlled during synchronized operation to accommodate multiple converter systems. Internal logic guarantees 50% maximum duty cycle operation to prevent transformer saturation.
The LT1681 incorporates a soft-start feature that provides a controlled increase in supplied current during start-up and after an under
voltage lockout or over
voltage/overcurrent event.
The part ...