JAJSNC5 april 2023 LM5171-Q1
ADVANCE INFORMATION
The inductor current has a triangle waveform, as shown in Effects of Parasitic Inductance on the Current Sense Signal and Zero Crossing Detection. TI recommends selecting an inductor such that its peak-to-peak ripple current is less than 80% of the channel inductor full load DC current. Therefore, the inductor must satisfy Equation 74:
Select Lm = 4.7 µH.
Then, the actual inductor peak to peak inductor current is determined by Equation 75:
The peak inductor current is determined by Equation 76:
Select an inductor that has a saturation current Isat at least 20% greater than Ipeak to ensure full power with adequate margin. In this example, TI recommends selecting an inductor of Isat > 49 A.
The power inductor full load Root Mean Square (RMS) current ILM_RMS determines its conduction losses. The RMS current is given by Equation 77: