DC1694B

Demonstration circuit 1694B is an isolated flyback converter featuring the LT®3748. The demo circuit is designed for a 12V output from a 22V to 75VDC 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, opto-coupler, 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 from vendors such as Würth Electronics, Sumida, Pulse Engineering and Coilcraft. Both EP13 and EFD20 core transformers can be assembled on the board. A two-stage filter is optional for applications requiring very small output ripple.

• Output voltage ripple (peak-to-peak) of 420mV
• Switching frequency of 289KHz at VIN = 48V, IOUT = 2.5A
• Efficiency of 86.5% at VIN = 48V, IOUT = 2.5A

Notes

ADI products are only authorized (and sold) for use by the customer and are not to be resold or otherwise passed on to any third party