TPS61299: TPS61299: input capacitance

Gustavo Adono

Part Number: TPS61299

Tool/software:

Hello,
I am using the TPS61299DRLR buck/boost converter in a project, as shown in the attached schematic. The circuit is supplying a load of up to 300mA, and I am using a 100µF/6.3V (C4) input capacitor. However, this capacitor is burning out during operation.

I would like to know:

What is the minimum recommended input capacitance to support a 300mA load?
What could be causing the 100µF/6.3V capacitor to fail?
Should I adjust the capacitance value or the voltage rating of the capacitor?

Thank you in advance for your help!

7 months ago

0 Federico Galli 7 months ago

TI__Intellectual 2210 points

Hi Gustavo,

Thanks for reaching out via e2e. May I ask you what is the input voltage (min, typical and max value of VBAT)? The minimum value for Cin is 2.2uF (as per datasheet). However, most likely the cap is blowing up because of the voltage rating. I would therefore increase the voltage rating of C4.

On another note, have you checked whether that output current can be drawn from the IC with the below equation?

Kind regards,

Federico

0 Gustavo Adono 7 months ago in reply to Federico Galli

Prodigy 80 points

The values of the input voltage are:

Min = 2.8
Typ = 3.2
Max = 3.6V

Yes, I reviewed the equation, and it is as expected and has behaved properly, thank you!

0 Nini Zhong 7 months ago in reply to Gustavo Adono

TI__Genius 13085 points

Hi Adono,

Did put the capacitor in reverse direction? Is this poly capacitor?

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TPS61299: TPS61299: input capacitance