LM5117: Power management forum

Hi Tim,

Thank you for the recommendation.  The LM5145 looks like a good match.

A couple questions:

1.) We have a large cap bank (500,000uF).  Will the LM5145 be able to handle the initial inrush and successfully charge this capacitance?

2.) With the LM5117, we were hoping to use the CM output to implement a CC/CV convertor.  For example, after the initial Cap bank charge, we want to limit current from the convertor to approx. 19A. Is the LM5145 capable of performing the CC/CV function as well?

Thanks,

John

Hi John,

See app note snva829 for CC/CV circuits. The LM5117 makes it easier as it has the CM pin. However, efficiency and thermal performance are likely critical here, hence the initial preference for the LM5145.

In terms of startup into a very high COUT, the CC/CV circuit should manage that. Otherwise, a very high soft-start (SS) cap value is required.

Regards,

Tim

Tim,

It looks to me like the LM5145 has OCP capability and will shut down when that limit is reached. However, it does not have the ability to operate and limit the current to some preset value below the OCP setpoint.  To do that I would have to implement a current sense resistor and feedback that voltage into the FB pin on the LM5145 as suggested in the appnote snva829. Am I correct in these assumptions?

Is there a controller with this current limit feature already built in?  Just trying to keep things simple here...

Thanks,

john