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Charging Supercapacitor 3.2V, 2000F from USB Type C Port with battery charger or buck-boost converter

JA G
Prodigy 40 points
Other Parts Discussed in Thread: LM34922, TPS62903, BQ24640

Hi TI Experts,

I am looking for a low cost and optimize solution like a battery charger ic or any other simplified solution to charge a supercapacitor that has 3.2V, 2000F ratings. 

I have seen this application note https://www.ti.com/lit/an/slva981/slva981.pdf?ts=1616168481450&ref_url=https%253A%252F%252Fwww.google.com%252F

which I believe it could be a good example of what I am looking for but the charging voltage in the application note design is too high for our application.

Do you have any suggestions? 

Kind regards,

JA

  • 0
    TI__Guru*** 143950 points

    Hi JA,

    Most of the TI LiIon battery chargers have a VBAT short protection feature that limits charge current to 100mA or lower if the battery voltage is sensed to be below 2.0V.  So, super cap charging up to 2.0V will be very slow.  Since most supercaps don't have the more stringent charge profile of a LiIon battery, you can use a dc/dc converter with current limit or, ideally adjustable current limit, and/or adjustable soft start to prevent charging the supercap at too high of current.   You might try TPS62903 with adj soft start or LM34922 with both.  

    Regards,

    Jeff

  • 0 in reply to Jeff F
    Prodigy 40 points

    Hi Jeff,

    Additional information on my initial post. The maximum charging voltage of the supercapacitor is 3.4V, and we want to charge them at max. current 3A, the source is from USB-C cable. The preferred method we want use on charging the super capacitor is constant current and constant voltage solution. So I am looking for a solution that would meet our requirement. Additionally, we to have a protection for the supercapacitor.

  • +1 in reply to JA G
    TI__Guru*** 143950 points

    Hi JA,

    A dc-dc converter always provides constant voltage protection.  If you find one with max current limit = 3A or adjustable current limit even through soft start, the you have constant current as well.

    The higher charge current BQ24640 controller with external FETs has trickle and precharge disabled and no timers to accommodate super caps.  It is intended for much higher than 3A charge current but will work for your application.

    Regards,

    Jeff