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WEBENCH® Tools/LM5175: LM5175

Banala Kranthikumarreddy
Prodigy 60 points
Part Number: LM5175
Other Parts Discussed in Thread: LM5118, , , LM5176, LM5170

Tool/software: WEBENCH® Design Tools

Hello, 

I am doing a project related with battery charging and discharging. I want to use a bidirectional buck boost DC DC converter for this purpose.

My specifications would be 

Lead acid battery 24 V (12 cells of 2 V)

Lithium ion 24 V (8 cells of 3.2 V)

Input voltage= 12 to 26 V. Ranges may vary but nominal voltage is 24 V

Output voltage= 12 to 26 V. Ranges may vary but nominal voltage is 24 V

It should be a bidirectional.

I see an Evaluation board with LM5175 is LM5175EVM-HP and the other controller is LM5118 with LM5118EVM

Now my doubt is whether the boards can be connected in parallel to two different batteries lead acid and lithium ion to increase the capacity. Is it possible to interface with the micro controller because my plan it to control the converter with micro controller such that the converter sends correct amount of voltages to charge the battery and discharge the battery to supply different small DC loads connected to the power supply when power is off.

I already spoke with TI technical support about this. They asked to contact here.

  • 0
    TI__Guru 68495 points

    Hi Banala,

    Thank you for your interests in TI solutions.  Please be advised that the LM5175 and LM5118 are both unidirectional controllers.  Also the LM5118 is non-sync buck-boost, which will be less efficient to support higher power than the LM5175.  You may need two in anti-parallel to achieve your bi-directironal operation.  Instead of the LM5175 and the LM5118, we recommend the LM5176, which is a newer part.

    Regarding the higher power, you can have two LM5176 in parallel to share the load.  Please refer to the following Application Notes for details.

    http://www.ti.com/lit/pdf/snva826

    Thanks,

    Youhao Xi, Applications Engineering

  • 0 in reply to Youhao Xi
    Prodigy 60 points

    But when I chat with the technical engineer support said those are bidirectional. Now your are asking to use LM5716 . I did not find any correct information about these. So, is LM5716 is bidirectional and is having capability to be interfaced with the micro controller. I want to connect the evaluation boards in parallel such that each board is connected with the battery like one with lead acid and another with lithium ion battery.

  • 0 in reply to Banala Kranthikumarreddy
    TI__Guru 68495 points

    Hi Banala,

    As I mentioned in previous reply, both the LM5175 and LM5176 are only unidirectional controller.  Neither one can implement bidirectional except using two ICs one for one direction.  

    We only have an bidirectional controller, LM5170. However, it supports buck in one direction and boost in the opposite direction.

    Hope this clarifies.

    Best Regards,

    Youhao

  • 0 in reply to Youhao Xi
    Prodigy 60 points

    So, the LM5170 is a bidirectional converter but it is not of buck boost topology. So, now Texas is not having any converter based on my specifications. I want a Bidirectional Buck Boost DC DC Converter. Could you please search one more time for the converter.

  • 0 in reply to Banala Kranthikumarreddy
    TI__Guru 68495 points

    As said, you need two LM5176 stage in anti-parallel configuration.  One for buck-boost operation  in one direction.   In addition, there is a UCDxxxx digital circuit which should be able to support your application. Sorry I forget the part number (not our product line). Since I am travelling, could you please post to d2d under digital power, and the responsible engineer will support you?

    Thanks,

    Youhao