BQ25883: VSYS output waveform

Mickey Lee

Part Number: BQ25883

Hi TI team,

Regarding “only 5V VBUS presence” condition, what register settings I shall write into BQ28883 to avoid its transient frequency switching (see the attached VSYS waveform)

and corresponding coil whine (at least I felt the whine sound was significantly audible)?

Thank you very much,

over 4 years ago

0 Jeff F over 4 years ago

TI__Guru**** 166786 points

Hi Mickey,

If you disable charge either /CE pin or bit or by ensuring the TS pin is not artificially in normal state when no battery is present, SYS will not have triangular waveform.

Regards,

Jeff

0 Mickey Lee over 4 years ago in reply to Jeff F

Prodigy 130 points

Hi Jeff,

In that case, what the VSYS voltage I can observe once I write EN_CHG bit (of REG06 bit[3]] as 0b0 to turn off the BATFET?

Kept still at 8.4V? Or 6.4V?

Regards,

+1 Jeff F over 4 years ago in reply to Mickey Lee

TI__Guru**** 166786 points

Hi Mickey,

With charge disabled and no battery installed, SYS regulates to the MINSYS/SYSMIN voltage not battery regulation voltage.

Regards,

Jeff

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BQ25883: VSYS output waveform