TPS63802: TPS63802DLAR getting issue to operate in Boost mode.

Hi Borad:

  I think the problem is related to the Vin rising UVLO , the typical value is 1.7V and the Vin falling UVLO , the typical values is 1.25V.

  question 1 : if you decrease the Input voltage below the 1.7V the output become 0V, since the input voltage is less than the VIN rising_UVLO.

  question 2 : please capture the waveform of IC VIN pin and check if  triggered the Vin falling threshold considering the inrush current draw from the input source during statup.

thanks,.

Hello Eric, 

As per testing, we have got the results as per attachment.

Kindly check it and let me know how I can get the desired results?

I am not getting the output voltage constant through the entire input voltage range. From Input side, I have set the current 5A .

Please suggest the option to run the design as per the requirement. TPS63802DLAR_1.3V-3.2V to 5.00V_1A.pdf(I/P 1.5V to 3.2V, O/P 5V 500mA-750mA)

I have also attached the designed schematic, Web bench schematic and test result.

8547.Test.xlsx

Hi Alpesh:

  AE Tao will help on this case , thanks. 

Hi Alpesh,

Do you have EVM on hand?  if yes, could you try with EVM only to evalute output capability, because it can help to avoid unexpected load.

For TPS63802, i think it can support your application unless UVLO_off be triggered.

Regards

Tao

Hello Tao,

Thanks for your reply.

I have review the design myself and found the issue in layout, the issue is that I have not routed the GND as per the recammandation.

I have rework the board by placing the GND jumper to make the switching loop shortest and the issue is resolved.

Now I can operate the design as Input 1.7V to 3.2V and Output 5V@500mA. 

As of now the IC is operated on 1.72V and UVLO rising is 1.7V but I need to operate the IC as 1.5V (UVLO rising should be 1.5V) to get the output of 5V@500mA to 750mA.

Can you suggest the chip to fullfill the requiement.

Thanks,
Alpesh 

Hi  Alpesh,

I am afraid TPS6380X is most suitable device for your application for now.

Other options should be TPS631000/10, TPSM83100/1. But they still can not full meet your requirment, the UVLO_rising is 1.6V for them.

Regards

Tao

Hello Tao,

Thanks for your input.

As per the Datasheet of TPS6308X, UVLO rising is 1.6V to 1.79V which is not meet my requirement. I need to get output voltage at 1.5V input.

Please suggest the best option from your side.

Regards,
Alpesh

Hi Alpesh,

Yes i know, but i think we have no device can totally meet your requirment for now.

For TPS6380X, it is advantage is it's low uvlo-off threshold.

For TPS6310xx/TPSM8310x, their advantage is their lower uvlo_on threshold(1.6V max)

But unfortunatly, both of then can not 100% meet your requirment, then, if your application can supply a higher voltage before start-up. TPS6380X will be more suitable. or else, TPS6310xx and TPSM8310x series will be better.

Could you let me know detail of your application? just want know why the input voltage range is so wide.

Regards

Tao

Hello Tao,

Thanks for the detais.

The application is like : we will get the input voltage from battery cell, either 1cell OR 2cell means 1.5V OR 3.2V and both the cased output will be 5V @ 500mA to 750mA which will be used for our application team.

Regards,

Alpesh.