特点
High Voltage: Operation Up to 72V
Synchronizable Operating Frequency and Output Switch Phase for Multiple Controller Systems
Fixed Frequency Operation to 350kHz
Adaptive and Adjustable Blanking
Synchronous Rectifier Driver
Local 1% Voltage Reference
Undervoltage Lockout Protection with Hysteresis
Input Overvoltage Protection
Programmable Start Inhibit
Transformer Primary Saturation Protection
Optocoupler Feedback Support
Soft-Start Control
典型应用
描述
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 undervoltage lockout or overvoltage/overcurrent event.
The part is available in a 20-lead wide SO package to support high voltage pin-to-pin clearance.