BQ25895: Not charging

Maxim Shabanov

Part Number: BQ25895

Hello, dear TI team.

In my application, I'm using BQ25895 IC for lithium battery charging and power management. But I have difficulties with that - IC doesn't charge the battery. When I connect the power supply (5.0V) IC consumes around 30 mA, meanwhile battery voltage is 3.5 V. When the power supply is unplugged on the PMID 5.13 V and on the VSYS - 3.53 V. I attach my schematic and I2C registers dump. What is happening and how can I put the controller into the charging mode? Firstly, I thought this is because of overheating the IC, so I resoldered with a hot air gun 4 more ICs, unfortunately, the result is the same.

5850.Schematic.pdf 5481.PCB.pdf

Thank you in advance!

over 4 years ago

0 Maxim Shabanov over 4 years ago

Prodigy 30 points

0 Ning T over 4 years ago in reply to Maxim Shabanov

TI__Guru 57781 points

Hi,

Please visit https://e2e.ti.com/support/power-management/f/196/t/874557 for BQ2589X: Schematic Review and PCB Layout Design Tips and https://e2e.ti.com/support/power-management/f/196/t/875386 for BQ2589x FAQs.

Please note that OTG (boost mode) is enabled by default for BQ25895. When battery only, the device enters OTG mode automatically. The boost mode can be disabled by OTG pin=LOW or OTG_CONFIG bit =1. Please refer to 8.2.5 Boost Mode Operation from Battery on the d/s for the details.

Thanks,

Ning.

0 Maxim Shabanov over 4 years ago in reply to Ning T

Prodigy 30 points

Thanks for answer Ning T, but my question was not about boost mode - boost works very well. I asked about charging mode of BQ. The IC doesn't charge batteris and ADC batterty register has 00 value

0 Ning T over 4 years ago in reply to Maxim Shabanov

TI__Guru 57781 points

Hi,

REG0C=C0 indicates OVP fault. Please disable OTG mode by setting REG03[5]=0 and try again.

Please refer to the video below for charger operations and valuable tips.

Battery charger system overview (training.ti.com/battery-charger-system-overview

Battery Charger Common Issues: Why my Battery is Not Charging (training.ti.com/battery-charger-common-issues-why-my-battery-not-charging

Thanks,

Ning.

0 user4484447 over 4 years ago

Prodigy 115 points

Hello, dear TI team.

I'm from China,and I can't supply my question in power managerment forum,so I text here.

I use BQ25895 to charge LI-battery-3.7V-3500mAh,when it charged to 4.0V,it's 100%,STAT LED is on.Then go on to charge,but it spent 15 hours to charge from 4.0V to 4.2V(STAT LED is off). It's so long.....

why.thanks.

Follow is sch.

0 Ning T over 4 years ago in reply to user4484447

TI__Guru 57781 points

Hi,

Please visit https://e2e.ti.com/support/power-management/f/196/t/874557 for BQ2589X: Schematic Review and PCB Layout Design Tips. It looks like some external components on the custom schematic do not follow the guidelines. Please update and try again.

Thanks,

Ning.

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BQ25895: Not charging