TPS61252 - About behavior at low VIN (out of recommended range)

Hi Kanemaru,

Note that the max UVLO of TPS61252 is 2.1V. So if Vin is 2.1V, IC will enter UVLO and shutdown.

Would you please share more information about the application environment and end equipment?  Perhaps we can give you some other suggestion.

By the way, why the load should be "47uF*2 + 1uF*2 + 0.1uF*2", instead of using a 100uF? Is there some other concern? I'm just curious about it.

BR

Gene

Hi Gene-san,

 

I apologize for not explaining enough.

It has been already decided that they use this device.

Therefore, they intend to do the design that does not reach "Vin=2.1V".

However Vin of TPS61252 may become "from 2.1V to 2.3V(out of recommended range)" by the inrush current.

Could you please let us know if you have the concern point other than UVLO?

 

[Answer]

-why the load should be "47uF*2 + 1uF*2 + 0.1uF*2", instead of using a 100uF?

-> This is demand specifications of the load device.

 

- Would you please share more information about the application environment and end equipment?

-> This circuits are as follows

 

Regards,

Kanemaru

Hi Kanemaru,
UVLO is the main concern, no other concerns.
As you said, large inrush or long trace PCB layout will introduce low Vin and lead to UVLO.
BTW, if your customer use one-cell Li-Ion battery as the input of IC, 2.75V should be the lowest input voltage. Why they need 2.1V application?

BR
Gene

Hi Gene-san,

 

Thank you very much for your help!

According to our customer, Vin range is “2.5V to 4.2V”.

However, Vin may drop to around 2.1V by the large inrush current.

 

Regards,

Kanemaru