Charging a SuperCap from a 3.3V battery source with LTC3459

Supercap charging with LTC3459

Supercap charging works fine with Vin=3V. However if we change to Vin=2V the output voltage Vout<=0.8V only (permanet, input current is 70mA) and the supercap is not charged anymore.

Also when we switch back to Vin=3V we still measure Vout<=0.8V. It seems LTC3459 is somehow damaged when changing Vin from 3V to 2V.

Any idea what could cause this?



  • 0
    •  Analog Employees 
    on Dec 1, 2020 9:05 PM 1 month ago

    We need a little more information.

    If you restart the LTC3459 (Vin down to 0, then back to 3V), does the cap charge up again? Or is it completely damaged and won't restart?

    When in the "damaged" state, does the IC seem to still be switching? Measure the SW pin on an oscilloscope. A screen shot will help. This will help diagnose the problem.