• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 547 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Li Ion battery charger with USB input and DC regulated output

Timothy Darling
Prodigy 120 points
Other Parts Discussed in Thread: TPS55330

Hello

I am looking for an Eval board that will charge 2 to 4 Li Ion cells at low to medium currents, with a USB input and a DC to DC regulated output at 12 V up to 500mA?

Does TI do an evaluation board like that?

Thanks

Timothy Darling

  • 0
    TI__Genius 13700 points
    Hello Timothy,

    First and foremost I want to make sure you are aware of the potential dangers of Li-Ion batteries and in particular cases where they are configured in series like you are intending on doing. Please be very careful and go to our Battery university site to learn more here:
    www.ti.com/.../battery-management-bms-university.page
    Batteries must be treated with respect or they can be very dangerous and the best way to respect something is to learn more about it.

    There are a number of TI EVAL boards that can charge 2 or 4 cells in series.

    The challenge that you are going to face is that a USB voltage of 5V is not high enough to charge more that one cell in series and 12V is not high enough to charge 4 cells in series. So depending on your use case and if you are wanting to support both input voltages and both cell counts you are going to need to have a boost converter on the front end between your 5V and 12V input sources to boost up to at least 18V so that you can support the peak charging voltage of a typical 4S pack which is 16.8V.

    Using that information you will have to size your boost converter for the worst case scenario which is 5V and a 4S pack meaning at the peak of charging you are going to need 16.8V at 500mA which is 8.4W which making an assumption of a power path with about 75% to 80% efficiency you will need a USB source that can support about 2.25A which also means your boost switch current capability needs to be greater than that as well.

    Also to switch between your two input sources you will need to have some sort of power MUX or diode OR'ing circuit otherwise if they can both be connected at the same time the 12V source will simply pump power into the 5V source

    All that said I think you could start looking at the following devices.

    Boost Converter: TPS55330

    Charger: Any of the chargers in the refined parametric search below will work.
    www.ti.com/.../battery-charger-ic-products.page

    Power MUX: Let me know if you intend on being able to have both a 5V and 12V supply connected at the same time and then we can work through a power muxing circuit.