TPS61093 - About startup waveform(Figure15)

VIN=3.6V, IOUT=50mA in datasheet, but in EVM, the load is 1500ohm. this is the reason of the difference.
(the test condition seem missed when the datasheet is transferred to new format)

Hi Jasper-san,

 

Thank you for the information.

I have one more question.

 

We would like to slow startup time of OUT when EN is High.

(Point of Red circles)

Does the slope of OUT become slow if we make soft start capacitor(C5) large?

If no, could you please let us know if you have any advice?

 

Regards,

Kanemaru

no, the internal mosfet is not controllable.
why this is importance for customer? may i know the application condition. i'm thinking maybe TPS61046 is possible.

Hi Jasper-san,

 

Thank you for your prompt reply.

Our customer worries about inrush current at startup of OUT.

Therefore, they would like to slow startup time of OUT when EN is High.

 

Regards,

Kanemaru

this current is to change the VOUT to (VOUT-0.7V), it depend on output capacitance and input voltage. it is only 200mA from the datasheet.

Hi Jasper-san,

 

I have one more question.

Does a soft start act during the following periods?

So, does this device start the switching?

 

Regards,

Kanemaru

Hi Jasper-san,

I forgot to attach file.

Regards,

Kanemaru

Hi Jasper-san,

Thank you  for your kind support!

I understand. Thank you very much.

Regards,

Kanemaru

Hi Jasper-san,

 

Sorry again for asking you this when you are busy.

I have one more question.

I understand that the internal isolation FET is turned on when EN pin is high.

Then, does the rise time of internal isolation FET become slow if the inrush current is large?

 

[Background]

Our customer compare "Figure3 of user’s guide" with "Figure15 of datasheet".

Then, they would like to know the cause that OUT and Vo are not the same voltage in Figure15.

 

 

Regards,

Kanemaru

it is OK, busy mean good business, please keep asking me question.
the reason is the the mosfet have large Rdson at low VIN and VOUT voltage condition. at VIN=3.6V , VO is approx. 3V, the P-MOFET's Rdson is high. so inrush current is limiting.