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LM46001-Q1: Output capacitance

Part Number: LM46001-Q1
Other Parts Discussed in Thread: LM46001

Hi,

I have a problem with the output capacitance of an LM46001. In my project i need a buffering capacitor with an series Diode
to avoid a discharge of this buffering capacitance during a low impedance supply interruption.

This buffering capacitor needs to be 2 x 470uF parallel.

For the LM46001 there are allready existing 4 x 10uF ceramic capacitors on the output.

In this case the LM46001 doesn't start up.

So i used a 1R series reesistor at this capacitors:

My Question is if this is possible to make a 1R resitor and why the buck converter IC works in this configuraton.

My second question is if this is a valid configuration.

Thanks for your help!

  • Hi Florian,

    I think you need to extend the soft-start time or limit the current to charge the large capacitor. 

    Because adding resistor you limit the current charging the capacitor such that LM46001 does not hitting a current limit during startup.

    You can probe the inductor current on your simulation to also double check whether the part hitting current limit during startup

    Thanks

    -Arief