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Using the BQ51050 to power a microcontroller

Other Parts Discussed in Thread: BQ51050B, BQ25100, BQ51003, BQ25120, TIDA-00318

I have found similar questions to mine on this forum, but I want to be sure that I am on the right track for my application.

I am currently powering a low power microcontroller (max current draw of about 16 mA, typically around 3 mA) with a 3.7 V button cell, but now I am looking into being able to use a rechargeable Lithium Polymer battery to wirelessly recharge the battery. But I need the microcontroller to remain on while it is being charged. From what I've seen, I think that the BQ51050B is what I need for the design, but I've never done inductive charging before, so I want to be sure.

Is this the right part for my application? And if so, are there other things I need on the battery-side, or do I just connect the BQ51050 in parallel with my controller and the battery?

Thank you.

  • Brad,

    When the bq51050B current limit is set, it will provide that current which can be shared by the battery and the system.  The termination current will be impacted by the load of the system directly.

    What is the capacity of the battery and what is your expected charge current?

    If these are relatively low (below 300mA - 400mA) you may consider a combination of the bq51003 + bq25100.  See the TI Design TIDA-00318 for an example.  Depending on what other features you need on your system, you may also consider the bq25120 for the charger.  It adds several nice features that may be a benefit.

    Regards,

    Dick

  • Thank you for your feedback. I'll look into the other chips that you suggested as well.

    The battery I am looking at using is a 65 mAh, and I'm not sure what the expected charge current will be.