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Original question:

LM317: LM317DCY

LM317: LM317DCY as a REGULATOR

G K Naveen Kumar
Prodigy 20 points
Part Number: LM317

Tool/software:

Hii team, 

I am using LM317DCY (U21,U18) as regulator to convert from 24-15 and 15-7 but output voltages are not as expected ...  Check the implemented circuit below for reference.

  • 0
    TI__Expert 4170 points

    Hi Naveen,

    Please take a look at the following from Page 11 of the datasheet. This is the circuit diagram to be used to make LM317 function as voltage regulator.

    As mentioned in Design Requirements, Cadj, D1 and D2 are optional.

    You will need two resistors R1 and R2 to set the output voltage. If R2 is a constant value, then you will have a fixed output voltage.

    The equation to calculate the output voltage is given at the end of the page. (Vref for the device is 1.25V)

    To get ~7.0V output, you could use R1 = 390Ω, R2 = 1.8KΩ

    To get ~15.0V output, you could use R1 = 240Ω, R2 = 2.7KΩ

    Regards,

    Bobby