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LT3922 Buck Mode Schematic

Hi,

The schematic for a buck mode LED driver written in LT3922 datasheet page 27 seems not correct.

I tried this schematic on LTspice but I could not get correct data. LT3922 seems not to work since VIN=VSW and ILED=0A.

If it is not correct, please send your recommended schematic for a buck mode.

Thanks,

Kazu

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  • Hi Kazu,

    LT3518 is also suitable to your application.

    FB pin is connected to GND since the buck converter is in constant current operation, and the current is controlled using the Rsense resistor. At Vctrl > 1V (since the CTRL pin is connected to Vref), the converter maintains the output current to be Iout = 100mV/Rsense. 

    The only thing left is proper selection of components. I will try to design a buck converter with this IC base on your specification.

    Regards,

    Dave

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