SuperCap Limit on TPS65910

Hi Bernd,

i have the same question on these restriction. We want to maximize the bridging period of the RTC. Unfortunately the RTC has a current consumption of 6uA. This results in only a few days backup time (with a 2000mF superCap).

I guess the maximum backup battery charging current (700uA) limits the usable capacitor!? What do you think?

Regards Frank

Hi Frank,

sorry for the delay. I do not use the RTC from the TPS65910, I use the RTC from an Am3352. I think the battery charger is a current source, so a current limit would not be the reason for a maximum capacity.

I'm still wating for an answer by a TI employee.

Regards Bernd

You may need to add this resistor to protect the super cap, if the super cap does not have current limiting ressitor. As soon as the charge start there will b huge inrush current and it can have undesired issues. So ite better to have one in series.

I understand the need for a protecting resistor. But that was not the question. I want to know why the super cap is limited to 2000mF.

Regards

Bernd