BQ4050: BQ4050 fuel gauge and BQ25720 as IC charger

Widji Santoso

Part Number: BQ4050
Other Parts Discussed in Thread: BQ40Z60, BQ25720, , BQSTUDIO, BQ25792

Hi,

So in our previous battery pack, we use bq40z60 as our all in one battery management solution. But, since we realize if this chip isn't suitable with our use case, where the system never get REST during it's operation (7x24h) then we decided to move from Impedance Track to CEDV algorithm for battery gauging. Here are our system environment and needs:

1. Always on Device

Our system will always on 24h even while charging. So, the battery pack will have no time to rest to get QMAX update

2. Power consumption

Our system need 0.5-2A of current consumption, using 4S Li ion 18650 as power source

3. Cordless appliance

Our system act as autonomous mobile robot with minimum "human interference" during the operations.

My question is:

Is this the right choice if we move from Impedance Track to CEDV algorithm? is there any concern of using this?
Is BQ25720 compatible work together with BQ4050? is there any other suggestion if there is another option of gauging and charging system?

Very appreciate for your help.

over 3 years ago

0 Wyatt Keller over 3 years ago

TI__Guru** 105770 points

Hello Widji,

The CEDV algorithm should be better for your system, as long as a qualified discharge occurs so the gauge can keep an updated FCC value.

Are you looking to use them together with the broadcast mode? What kind of compatibility are you looking for? The gauge and charger both support 1-4S batteries and use SMBus, so a combination of the two should work in your system.

Sincerely,

Wyatt Keller

0 Widji Santoso over 3 years ago in reply to Wyatt Keller

Prodigy 90 points

Hi Wyatt,

So, in my understanding CEDV take advantage of using voltage as function of RSOC. is this ok with current load fluctuation? will it affect RSOC reading since the voltage fluctuation?

Are you looking to use them together with the broadcast mode? I'm not really sure, I'm not too familiar with this chips. but, we need more like bq40z60 like if we want to set the charging current, setting temperature and everything in advanced charge algorithm from bq4050, it will automatically updated to the charger IC. is this possible to do? or we still need "external MCU" to make this happen?

Thanks,

Widji

0 Wyatt Keller over 3 years ago in reply to Widji Santoso

TI__Guru** 105770 points

Hello Widji,

The CEDV algorithm relies heavily on the coulomb counter for SOC calculations, it uses voltage and temperature for compensation during discharge. Gauging should be similar to the impedance track.

You can use the advanced charge algorithm page to setup the BQ4050 to broadcast to the charger. We are releasing an application note soon regarding how to set this feature up. Essentially if the gauge and charger are the only devices on the communication bus you should be able to set it up similar to how the BQ40Z60 was setup.

Sincerely,

Wyatt Keller

0 Widji Santoso over 3 years ago in reply to Wyatt Keller

Prodigy 90 points

Hi Wyatt,

Seems like everything is ok now. but, I am unable to find bq2572x family on the latest BQStudio. is there any addon that must be installed?

Thanks,

Widji

+1 Wyatt Keller over 3 years ago in reply to Widji Santoso

TI__Guru** 105770 points

Hello Widji,

My bqStudio version does have the bqz file for this charger, try updating your bqStudio. I'm using 1.3.104.

I also attached the bqz you can place in the config folder of the bqStudio install path.

/cfs-file/__key/communityserver-discussions-components-files/196/Charger_5F00_1_5F00_00_2D00_BQ25720.bqz

Sincerely,

Wyatt Keller

0 Widji Santoso over 3 years ago in reply to Wyatt Keller

Prodigy 90 points

Hi Wyatt,

See.. I only able to find the stable version 1.3.101 on the download page. thanks for the enlightenment Wyatt!

Thanks,

Widji

0 Wyatt Keller over 3 years ago in reply to Widji Santoso

TI__Guru** 105770 points

Hello Widji,

Yes the stable version is a couple versions behind, we always recommend using the test version because it has the most bug fixes.

Sincerely,

Wyatt Keller

0 Widji Santoso over 3 years ago in reply to Wyatt Keller

Prodigy 90 points

Hi Wyatt,

Sorry to bother you again, I found another ic charger controller, say it BQ25792 with integrated switching MOSFETs. But, it's interface is using I2C instead of SMBus. Can we use this IC to work together with BQ4050 in broadcast mode?

Thanks,

Widji

0 Wyatt Keller over 3 years ago in reply to Widji Santoso

TI__Guru** 105770 points

Hello Widji,

No you most likely will not be able to use an I2C charger with SMBus gauge in broadcast mode. The device address, ChargeCurrent(), and ChargeVoltage() are most likely different for the I2C charger and the gauge cannot be configured for different addresses/registers because it's defined in the SBS spec.

There's a new application report outlining what to look for: www.ti.com/.../sluaaf8

Sincerely,

Wyatt Keller

0 Widji Santoso over 3 years ago in reply to Wyatt Keller

Prodigy 90 points

Hi Wyatt,

That's great.. I already keep up with your app note before. We are currently ordering EVM boards, can't wait to try it soon.

Thanks,

Widji

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BQ4050: BQ4050 fuel gauge and BQ25720 as IC charger