BQ25883: BQ25883 VBAT ADC REG1D & REG1E

Mickey Lee

Part Number: BQ25883
Other Parts Discussed in Thread: BQ28Z610, BQ40Z50,

Hi TI Team,

Our speakerphone product (with a woofer driver) would draw a highly significant pulse current load while a bass melody (drum, piano, cello etc.) playback is running (with max. volume) and

this transient current load inevitably causes hundreds of mV VBAT drop inside the 2-cell serial battery pack (even higher 600mV), we definitely read REG1D & REG1E of VBAT ADC during the

product is consuming a light load and calculate a reasonable RSoC % of VBAT capacity, how many consecutive ADC readings are we advised for the RSoC calculation?

Thank you,

over 4 years ago

0 Wyatt Keller over 4 years ago

TI__Guru** 105760 points

Hello Mickey,

I'm not sure if this is a charger related question, if you are looking to calculate RSOC then you should use a gauge like the BQ28z610 or BQ40z50 to calculate state of charge. If you are trying to directly correlate the battery voltage to a RSOC value, it is up to your system for how many voltage samples you need to smooth out the voltage enough, if you have continuous high current draw the wrong RSOC may be calculated due to the voltage drop.

Sincerely,

Wyatt Keller

0 Mickey Lee over 4 years ago in reply to Wyatt Keller

Prodigy 130 points

Hello TI Team,

Understood,

Forgot one, does TI BQ25883 have time-period limit of being read these two VABT ADC registers?

Thank you,

0 Wyatt Keller over 4 years ago in reply to Mickey Lee

TI__Guru** 105760 points

Hello Mickey,

If you're looking for the ADC conversion rate, it's in the datasheet section 7.5 Electrical Characteristics on page 10.

Sincerely,

Wyatt Keller

0 Mickey Lee over 4 years ago in reply to Wyatt Keller

Prodigy 130 points

Hello TI Team,

Does ADC conversion work without VBUS (REGN is off but battery pack present only)?

I mean, can the host read VBAT ADC in such battery-discharging condition?

Thank you,

Mickey

+1 Wyatt Keller over 4 years ago in reply to Mickey Lee

TI__Guru** 105760 points

Hello Mickey,

The REGN will go high when an ADC measurement is taken, you should see REGN pulse every time there is an ADC measurement. During switching REGN is always high.

Sincerely,

Wyatt Keller

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BQ25883: BQ25883 VBAT ADC REG1D & REG1E