• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 62 subscribers
  • Views 58 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

TLV62065: observing a ringing being propagated through the regulator TLV62065DSGR

BQ25601: output ring observed when input is provided to BQ25601RTWR which affects the other regulators

Aagneya C
Prodigy 40 points

Part Number: BQ25601

We are using BQ25601RTWR in our design (telematics product) and we are observing an ring at the output of the IC when the input supply is given(12V) which is passed through a protection circuit and a 5V buck regulator whose output is given to the battery charger IC input.

We are also using an battery of 1500mAh(4.2V) which is connected to the battery charger IC and provides power when there is no input present. and similar ringing is obsevred with the battery connected.

Is there any way in which we could make sure that the input ringing observed is not getting propogated at the output?

Also what is the time that the battery charger requires to switch between the internal battery (VBAT) to external supply (VIN).

Waveform references

1)yellow line: External input supply(12V)
2)blue line: battery charger IC output (without internal battery connected)

 

1)Yellow line: External input supply(12V)
2)blue line: battery charger IC input (without internal battery connected)



Kindly provide suggestions to mitigate the ringing on the output of the battery charger IC.

 

FYI, circuit reference.

image.png

Regards,
Aagneya C

  • 0
    TI__Mastermind 42665 points

    Hi Aagneya,

    What you are showing is a SYS transient that occurs on startup. From the looks of the first waveform, the 12V supply has some ringing itself. My first recommendation would be to control the input turn on to avoid ringing that could be passed to the BQ25601.

    Second, there are a number of things that could be done to improve the performance of the BQ25601:

    1. Improve layout so that PMID, SYS, and BAT capacitors are as close to their pins as possible.

    2. Implement the RC snubber on the SW node you have available.

    3. Consider extra filtering such as a ferrite bead.

    Please see Section 9.3.3, it takes a few seconds to power on the input.

    Regards,

    Mike Emanuel