BQ25731: ADCIBAT and ADCIIN always 0

LEANDRO SCHMITZ

Prodigy 220 points

Part Number: BQ25731

Tool/software:

Hello, I`d did my project based in TIDMAR6, and I`m facing some problem to get ADCIBAT, ADCIIN and to limit current.

ADCIBAT and ADCIIN register always came 0 frorm i2c get, I`m metering 720mA using a multimeter.

My desing is to charger 12V lead acid battery from 15.6V supply and 1.2A;

I appraciate your help.

Thanks

Regards

Leandro

7851.Battery.pdf

10 months ago

0 LEANDRO SCHMITZ 10 months ago

Prodigy 220 points

Hi, put some metering, with driving 1.4A from charger.

IADPT pin:

IBAT pin:

0 Tiger Zhou 10 months ago

TI__Mastermind 32745 points

Hi, Leandro,

To read the ADC values, first to enable the ADC channel, then start the ADC_START=1.

Regards,

Tiger

0 LEANDRO SCHMITZ 10 months ago in reply to Tiger Zhou

Prodigy 220 points

ADC Option(3ah/3bh) = 0x20ff - All channels are enabled

To read I do 3bh = 0b01100000 and wait for bit6 to got 0.

After that I get VBus, VBat, IIn and IBAT.

Only current is comming 0

this code was working before I changed the mosfet used in the charger.

I would like to know if it could be a hardware issue?

Thank you

0 LEANDRO SCHMITZ 10 months ago in reply to LEANDRO SCHMITZ

Prodigy 220 points

Hello Tiger,

It seems to me that the average voltage levels are low on the feedback pins IBAT and IADPT, for a current of 1.4A and shunt of 10mR, with gains of 16x and 20x.

Is there anything I can do to improve these signals?

0 Tiger Zhou 10 months ago in reply to LEANDRO SCHMITZ

TI__Mastermind 32745 points

Hi, Leandro,

That is right, you can use a high value RAC/RSR such as 20-mohm, and set the IADPT_GAIN=40X, IDCHG_GAIN=16X.

Regards,

Tiger

+1 LEANDRO SCHMITZ 10 months ago in reply to LEANDRO SCHMITZ

Prodigy 220 points

The problem was 10mR resistor, I was wrong PN.

Thank you for help

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BQ25731: ADCIBAT and ADCIIN always 0