Part Number: TPS2500
Other Parts Discussed in Thread: BQ25890H,
I have a TPS2500 regulator whose inductor (or maybe capacitor) is singing at a high frequency. It doesn't always do it, it depends on the input voltage. What I observed was when the input voltage exceeds about 4.32V, then the output ripple will change and the circuit starts to sing. Now the input is fed from a TI BQ25890H charger so the input voltage can go from 3.0V - 4.42V. So my questions are: Do you have any advice on how to keep it from singing, and then do these output waveforms look reasonable for this part under light load (less than 200mA)?
This is our schematic. Currently there is a less than 200mA load connected to AUX and simple USB mouse connected to the USB output. VSYS goes from 3.0V - 4.42V as the battery charges.
Here are some waveforms I captured of the aux output VCC_5V1. I've set the probe coupling to be AC so I could get more dynamic range on the ripple.
This is a zoomed out view of the quiet mode.
This is a zoomed in view of the quiet mode
Singing zoomed out view
Singing close up
Thank you
