DC1694A

Evaluation Board, Flyback Regulator, Demonstration Board for 100V Isolated Flyback Converter

The demonstration circuit is an isolated flyback converter featuring LT3748EMS device. The LT3748EMS 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. The demo circuit is designed for a 12V output from a 22V to 75V DC input. The output current is up to 2.5A. The part senses the isolated output voltage directly from the primary side flyback waveform during the off time of the power switch. No third winding, optocoupler or signal transformer is required for regulation. A minimum load of approximately 2% of maximum load is required on the output to maintain regulation. The demo circuit can be easily modified for applications of different input and output voltage/current, with some pre designed transformers.

.

Switching frequency of 289KHz

.

86.5% efficiency

.

Boundary mode operation

.

Primary side winding feedback load regulation

.

VOUT set with two external resistors

.

INTVCC pin for control of gate driver voltage

.

Programmable soft start

.

Programmable undervoltage lockout

If higher operating voltage is required, power components with higher voltage ratings should be used.