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LM25116: Constant Current using LM25116

Pradeep Raaj k
Prodigy 90 points
Part Number: LM25116

Hi ,

I tried to make a cc cv buck converter using lm25116 IC.I made the CC circuit similiar to this. My cv is working properly but not my CC. I dont know how to add cc to the existing circuit. Please help me further. I attached my schematic in this. There is a mistake is the schematic. The current sense resistor must be at the negative ground side. I dont know how to proceed further. I could not understand how cc cv works in pwm controller ic. I could not understand the application note from TI also. Help me with calculation of TI application note. I wanted to create a variable cv of 2.5-16v ( which is working fine ) and cc of (0-20A)..

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  • 0
    TI__Mastermind 25590 points

    Pradeep,

    I believe the issue is with the op amp circuitry. See the comparison of the schematic from the video vs your schematic below. The video schematic has a differential amplifier (same as yours) with a gain of 30 (yours is a gain of 100). This connects to an amplifier with a reference voltage (yours has an extra capacitor and doesn't appear to have a reference voltage).

    I recommend connecting test signals to the op amp circuitry to independently verify that it is working as expected.

    -Sam

  • 0 in reply to Samuel Jaffe
    Prodigy 90 points

    Thank you for the reply. I tried using current sense on the ground side, and used in comparator configuration. This works for me.