BQ25306: What affect the STAT blinking interval ?

Nan Liu

Prodigy 110 points

Part Number: BQ25306

Tool/software:

Hi TI support team:

I have picked the BQ25306 for my charger as schematic below. I have a question about the STAT pin blinking frequency,

when I remove the battery from the charger It blinks about 10Hz other than 1Hz as the datasheet scribed.

I red some of the previous posts about the same question, but not understand what exactly the cause of the blinking frequency.

Would you please explain what component would change the frequency ? This is important that we want to take the LED to be

the charger status display to the user, but we don't want it flashing fast.

Thanks

Nan L.

6 months ago

0 Ning T 6 months ago

TI__Guru 57741 points

Hi Nan,

Please refer to the FAQ below. The principle is the same for BQ25306. If STAT blinking is not preferred, please disable the charger by /EN pin.

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1022795/faq-bq25601-faq-why-does-the-led-connected-to-stat-pin-flashes-and-the-sys-voltage-unstable-when-battery-is-not-connected-for-bq25601-bq25601d-bq25606-bq25611d-bq25616-bq25616j-bq25618-bq25619-bq25600-bq25600d-bq25600c

Thanks,

Ning.

0 Nan Liu 5 months ago

Prodigy 110 points

Hi Ning,

There is another issue I found. When the charge current dropped down to 10% of the fast charge current (36mA from my circuit), the charge won't stop, the STAT pin still pulled down. The STAT pin never pull high even the charge current is zero. What could be the problem?

0 Ning T 5 months ago in reply to Nan Liu

TI__Guru 57741 points

Hi,

What's the corresponding BAT pin voltage? The device terminates a charge cycle when the battery voltage is above recharge threshold and the charge current is below termination current.

Thanks,

Ning.

0 Nan Liu 5 months ago in reply to Ning T

Prodigy 110 points

Hi Ning,

The BAT pin voltage stays on 3.6V (one cell battery), and never above it along with the whole charge current dropping progress. When the current is dropped to "zero", the STAT still "low", I think the charge cycle should be terminated before the current is zero, so the STAT should be "open" at 36mA point but it never did so even the charge is stopped (zero current).

0 Ning T 5 months ago in reply to Nan Liu

TI__Guru 57741 points

Hi Nan,

What's your target battery charge voltage limit?

Thanks,

Ning.

0 Nan Liu 5 months ago in reply to Ning T

Prodigy 110 points

The target battery voltage is 3.6V for a 1-cell LiFePO4 battery, this is where when the charger already reached this voltage but not stop the CV charging progress.

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BQ25306: What affect the STAT blinking interval ?