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LMR14030-Q1: slope compensation

K.Hamamoto
Guru 12155 points
Part Number: LMR14030-Q1

Hi

This device is peak current mode converter. And this has a slope compensation.

Is there any limitation for the inductor value ? I understand the inductor is related to ripple current. We need to calculate the min value of inductor for that ripple is small what the we want. 

On the other hands, the inductor value is related to the current slope. So that . Is there any limitation of the inductor for concerning the sub-harmonic oscillations?

(Are there no any limitation because this device has slope compensation?)

Regards,

Koji Hamamoto

  • 0
    TI__Expert 5745 points

    Use this equation as below

    Set the Kind=0.2~0.4, you can get a suitable ripple and a small L.

  • 0 in reply to Vental Mao
    Guru 12155 points

    Hi Vental-san,

    Thank you for your support. And I am sorry for the late reply.

    I understand the minimum inductance can be calculate the above equation.

    However at the following comment on the datasheet it is mentioned about not recommend too small inductor current ripple which means the large inductor. 

    My question is that there is or not the limitation of maximum inductor value.

    How much is the small of an inductor current ripple not allow?

    Regards,

    Koji Hamamoto

  • 0 in reply to K.Hamamoto
    TI__Expert 5745 points
    For max inductor, which also means the min current ripple for the detection internal.

    The max inductor will decrease the loop bandwidth and cause the device unstable.

    Normally, we want to set the current ripple is more than 0.2* Iout for detection internal in the current mode control.