BQ51050B: BQ51050B Integration with Fuel Gauge

Daniel McLane87

Part Number: BQ51050B
Other Parts Discussed in Thread: BQ24040,

Our design uses BQ51050B for wireless charging and also BQ24040 for wired charging. Battery is LiPo, 500 mAh

We also have a fuel gauge which is On Semi LC709203FQH-01TWG.

Both charging methods work fine. Problem is that during charging the fuel gauge always reads 100%, because the fuel gauge detects the charging voltage and thinks the battery is fully charged.

One way to work around this limitation would be to temporarily interrupt charging, allowing the fuel gauge to accurately measure the battery level.

Is there a way to halt the charging on BQ51050B without causing a disconnect? Can TS/CTRL be used for this function?

Thanks

over 4 years ago

0 Bill Johns over 4 years ago

TI__Guru 65796 points

Hello

Most of the TS/CTRL functions will send an End Power Transfer (EPT) that will turn off the TX, this would probably be the disconnect you do not want.

Do not think we have a charge suspend option. Will check a few things and get back with you.

0 philip Cannon over 4 years ago in reply to Bill Johns

Prodigy 140 points

I have the same problem . I thought about setting TERM to 0 but others have said that will disable the charger termination so

I do not think it will work.

In my earlier post Bill Johns said

* The RX will send End Power Transfer (EPT) and TX will turn off. Unit will restart when the voltage is removed from TS but restart time
* will depend on the TX.
*
*
* Best Regards,
*
* Bill Johns, Applications Engineer

I need to know how long after taking TS_CTRL high it will take to actually turn off the charge current coming out of BAT.

does this also depend on my wireless transmitter chip ?

Phil

0 Bill Johns over 4 years ago in reply to philip Cannon

TI__Guru 65796 points

We have a similar discussion in the below thread.

https://e2e.ti.com/support/power-management/f/196/t/836899#pi320995=2

Also if disabling termination is an option see below post that Phil found.

The below is from a post by Dick Stacey in 2015:

The question and solution is how to disable termination and below is the right approach. With TERM Float or Ground the device will not terminate, send charge complete EPT, voltage will remain applied to pack.

NOTE the caution regarding 10 hr safety timer.

This will NOT stop or disable charge only termination.

https://e2e.ti.com/support/legacy_forums/wireless_power/f/693/p/394794/1404022

0 Daniel McLane87 over 4 years ago in reply to Bill Johns

Prodigy 50 points

Thanks for your help!

Power management

Power management forum

BQ51050B: BQ51050B Integration with Fuel Gauge