TPS61032: Noise at VBAT and VOUT due to SW signal

Here is the schematics.

Hi Newton,

Could you please check the technique you are measuring the VBAT? The right way to measure the VBAT (input voltage ripple) is to use pigtail.

See below training course for how to measure ripple in right way:

https://training.ti.com/power-tips-measuring-vout-ripple-dcdc-converters?keyMatch=OUTPUT%20RIPPLE%20MEASUREMENT%20FOR%20DCDC&tisearch=search-everything&_ticdt=MTYyNDQ5NzQ2OHwwMTc4YTU4YmJkOGUwMDg2YTViNDIyMmU4ODkwMDMwNzMwMDI5MDZiMDA5Nzh8R0ExLjMuMTA1ODE2MzAwOS4xNjE3Njg1MTA0

-Wenhao

Hi Wenhao,

Thank you for the answer.

I'm afraid that the signal I've captured at VBAT power supply input appeared not due to an unsuitable setup of measurement, but due to the switching at SW pin.

Please take a look at the  picture below, that depicts a pulse at VBAT, whose ∆X and ∆Y values are respectively 136 microseconds and 542 milivolts. It is a huge pulse. The time interval is coincident with the switching of SW.

Would it be caused by an ill-dimensioned inductor or input capacitor?

Best wishes,

Newton