100V Isolated Flyback Controller

The LT3748 is a switching regulator controller specifically designed for the isolated flyback topology and capable of high power. It drives a low side external N-channel power MOSFET from an internally regulated 7V supply. No third winding or opto-isolator is required for regulation as the part senses the isolated output voltage directly from the primary-side flyback waveform.

The LT3748 utilizes boundary mode to provide a small magnetic solution without compromising load regulation. Operating frequency is set by load current and transformer magnetizing inductance. The gate drive of the LT3748 combined with a suitable external MOSFET allow it to deliver load power up to several tens of watts from input voltages as high as 100V.

The LT3748 is available in a high voltage 16-lead MSOP package with four leads removed.

Applications

* Isolated Telecom Converters

* High Power Automotive Supplies

* Isolated Industrial Power Supplies

* Military and High Temperature Applications

* 5V to 100V Input Voltage Range

* 1.9A Average Gate Drive Source and Sink Current

* Boundary Mode Operation

* No Transformer Third Winding or Opto-Isolator Required for Regulation

* Primary-Side Winding Feedback Load Regulation