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LM5160 as inverting mode

Other Parts Discussed in Thread: LM5160, LM5005, LM46002, LM5085

We would like to know the LM5160  can use for inverting mode and will it work for low load condition??

Our requirements.

Input 24VDC

output -24VDC/1.5A load current. and some times our load should be zero (it has to work in low load condition also..).

Can you suggest some more IC for your application???

  • I will forward your question to non-isolated forum for better support.
  • Hello Geo,

    Apologies for the delayed response.
    The average value of the inductor current in the inverting buck boost topology is not same as the output load current (as in the normal Buck topology).
    The average value of the inductor current is given by Iout/(1-D) where D is set as | VOUT |/(| VOUT |+VIN ) (D =0.5 in your case). Therefore the average value of the Inductor current will be ~3A in your application (for 1.5A load current). Added to that, you will have the ripple component and the peak value of the inductor current will be more than the the typical peak current current of the HS (FET ) set at 2.5A, which will trigger the current limit for the part. However, you can still make it work for lower load current (upto say 0.9A) as long as the peak current of the inductor is less than the 2.1A (minimum value).

    You can look for a regulator (LM5005, LM46002 can be a few options; with LM5005 you will need to probably need to play with an additional resistor between the IS and PGND to change the emulated peak current limit point) with higher peak current limit or for a controller (LM5085) with adjustable peak current limit point.

    Regards,
    Sourav
  • AS you suggested LM46002 will work for us.But our load condition is slightly different, some times no load condition also will occurs(light load).Will this ic work for Zero load condition? and our Actual Load current will be 750mA.
  • Yes, the IC works under no load condition. Please refer to this app note for more details
    www.ti.com/.../snva722b.pdf
  • Hi sorry for the incorrect input.i missed one of the major requirement to share you.

    we are planned to use LM46002 for the inverting switching converter.

    our load condition has high transient current.

    input=24V

    output=-24V

    Output current

          Steady state Load Current=750mA

         Transient load current=10A

          and It has to work in the zero load current as well

    when i read through the data sheet i found that this IC has hiccup mode features.In our case transient current is 10A. the Hiccup mode will be a concern for us. could you give me a suggestion on this??