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LM5022: LED driver application for flexible Vout(Vf) range

Guru 19475 points
Part Number: LM5022

About LM5022 design for LED driver application based on application note: snva282b and snva229a, is there any idea for set flexible Vout range by external setting?

I want to correspond Vout (Vf): 45V~110V for depend on situation. (Iout: 0mA ~ 450mA)

But snva282b schematic is fixed RB, equal to fixed Vout.

Best regards,

Satoshi

  • Hi Satoshi,

    Thank you for your interests in the LM5022.   You can feed a voltage signal through a resistor to RFB1 to alter the feedback, hence adjusting the output voltage level.

    Note that without the feed:  VRFB1= Iout x Rsns x RFB1 / RFB2.

    With the Vcontrol to feed to VRB1,  VRFB1 = Iout x Rsns x (RFB1 // Rcontrol) / RFB2 + Vcontrol x RFB1 / (RFB1 + Rcontrol) 

    Thanks,

    Youhao