TPS61089: Minimum input current for TPS61089

Dear Kanesan,

Thank you for considering the TI part.

If you want to generate 7.2V/2A to charge the Li-Po, then the USB output current need to >3.2A.  If you want to generate 7.2V/1A to charge the Li-Po, then the USB output current need to >1.6A.

So actually, the limit is come from the USB output capability, not the TPS61089.  What is the maximum output capability of the USB in your application?

Dear Kanesan,

If their USB maximum output current is the same as yours, then their product also can't output 7.2V/1A to change the battery. 7.2V/0.5A is possible. Or they use a higher current rating USB port.

If the charge current is not important, then you can set a lower charge current like 0.5A or even small.

But anyway, TPS61089 is not suit for this application. You could choose TPS61175 in Sepic topology to limit the input current.

Hi  Kanesan，

For the power conversion, the input power should be higher than the output power. so 5Vin/1A Iin is OK to support 7.2V/0.5A output, but 5V/0.5A in to provide 7.2V/1A out is impossible.