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Soft start on LM2588-ADJ

Other Parts Discussed in Thread: LM2588, LM5158

Hello everyone,

I am using LM2588 adj IC for boosting 12V to 40V. 

I have the inrush current problem when I turn on the device with a Cout=1000uF (about 5.5A with a Ccomp=330nF and Rseries=2.94K)

If I replace the value Ccomp =2,2uF  I halve the inrash current when I turn on the device.

Is it a correct operation?

Can malfunctions occur durin normal operation?


  • Hello Danilo,

    Are you using the device for a boost converter or for a flyback converter?

    In general the right solution would be to extend the softstart time. This is not possible with the LM2588, so possibly you might have a look at LM5158 to reduce the inrush current without sacrificing the normal operation.

    If you change the compensation as you did, any load transient will be very slow.

    Best regards,

  • Hello Brigitte,

    Thank you for your answer and your suggest about LM5188 but It's different footprint. The LM5158 is fantastic for a new design.

    Now, I'm trying the right compromise between inrush current (about5.5A) when turn on the device and the transient during the normal operation (about 1A) considering Cout 1000uF for fast transient.

    Thank you

    Best regards