TPS61025 Cout limitation....

Peter Tseng

Mastermind 6170 points

Other Parts Discussed in Thread: TPS61025

Dears,

Is there anyone know what is the Cout value limitation?(Max.)

My customer use TPS61025 to boost 1.5V battery voltage to 3.3V and work well.

However, while the battery voltage drop down to around 1V, and sometimes they will have heavy loading.

In this situation, there will have problem for Vout, customer try to enlarge the Cout value to around 500uF and it seems works.

But there is no any information about Cout in datasheet!

Is there any side effect to enlarge the Cout and what is the proper value if customer want to do so?

Thanks.

over 11 years ago

0 Jasper Li over 11 years ago

TI__Mastermind 46905 points

What is the output current when Vout has the problem. and what happen at Vout? i'm thinking if the current limit is triggered.

thanks

Jasper li

0 Peter Tseng over 11 years ago in reply to Jasper Li

Mastermind 6170 points

HI Jasper,

The average current is around 70mA but with peak current of 300mA for 50ms.

When TPS61025's the input voltage is 0.95V, customer found the 3.3V output will drop to 2.8V.

Thanks.

0 Peter Tseng over 11 years ago in reply to Peter Tseng

Mastermind 6170 points

Dear sirs,

Is there anyone have idea about this concern?

Thanks.

0 Jasper Li over 11 years ago in reply to Peter Tseng

TI__Mastermind 46905 points

Very sorry for the late reply. the device will OCP at Vin=0.9V and Iout=300ma. but since it is just current pulse, increasing the output capacitor seem can solve the problem

i worry about the stability at large Cout, and based on my measurement the device work fine at Cout=200uF, but i had not measure at the conditon of Cout=500uf. i suggest the customer can measure the device's transfer function, or estimate the phase margin through load respond.

thanks

jasper

Power management

Power management forum

TPS61025 Cout limitation....