BQ21061: BQ21061 charge done question

Wei Ken Ting

Prodigy 210 points

Part Number: BQ21061
Other Parts Discussed in Thread: BQ21060

Hi TI team ,

I use BQ21061 EVM and default register setting for charging experiment.

When charge done , BQ21061 still have 14 ~ 15 uA current inject to battery.

Is it normal status ?

Follow BQ21060 charge flow , when charge done it should turn off BATFET.

over 5 years ago

0 Raheem over 5 years ago

TI__Mastermind 21590 points

Hello,

The BATFET should turn off after charge termination occurs. How is the current measured? Is anything else connected to the battery pin?

0 Wei Ken Ting over 5 years ago in reply to Raheem

Prodigy 210 points

Hello Raheem ,

Please refer the picture as below :

If the BATFET turn off , still small current inject to battery occurs , is it normal ?

0 Raheem over 5 years ago in reply to Wei Ken Ting

TI__Mastermind 21590 points

Hello,

IS VIN present when you make the measurement? Does the current change when you set /LP low?

0 Wei Ken Ting over 5 years ago in reply to Raheem

Prodigy 210 points

Hello Raheem ,

VIN =5V is present when I measure. BQ21061 EVM indicate status is charge done.

So I set LP pin to low in BQ21061 EVM , the measure current still keep 14 ~ 15 uA.

Could I set other configure for EVM ?

0 Raheem over 5 years ago in reply to Wei Ken Ting

TI__Mastermind 21590 points

Hello,

Can you have /LP low and remove VIN and measure the BAT Iq.

Make sure J4 jumper is removed. Also remove J16

0 Wei Ken Ting over 5 years ago in reply to Raheem

Prodigy 210 points

Hi Raheem ,

As below is my action step :

1. VIN is remove , measure BAT iq is 1.4 uA (Set L/P low , remove J4 and J16 , CE pin is low for charge action is enable)

2. VIN is remove , measue BAT Iq is 1.4 uA (Set L/P low , remove J4 and J16 , CE pin is high for charge action is disable)

3. VIN is present , measue BAT Iq is 14 ~ 15 uA (Set L/P low , remove J4 and J16 , CE pin is low for charge action is enable)

4. VIN is present , measue BAT Iq is 14 ~ 15 uA (Set L/P low , remove J4 and J16 , CE pin is high for charge action is disable)

It seems VIN is present or remove , BAT Iq still have small current inject to Battery.

Is it normal status ?

0 Raheem over 5 years ago in reply to Wei Ken Ting

TI__Mastermind 21590 points

Hello,

There will be battery Iq when VIN is absent because system will be powered by battery.

LP does not have any effect when VIN is present.

Can you place a load on PMID with battery only present to calibrate the battery current is measuring correctly?

0 Wei Ken Ting over 5 years ago in reply to Raheem

Prodigy 210 points

Hello Raheem ,

I place a 10K resistor load on PMID and measure BAT Iq current value as below :

BQ21061 EVM indicate charge done status.

1. VIN is present , BAT Iq is still 14 ~ 15 uA , but the current direction is form Battery to BAT pin.

2. VIN is disconnect , BAT Iq is 1.4 uA , the current direction is also form Battery to BAT pin.

Is it normal situation ?

0 Raheem over 5 years ago in reply to Wei Ken Ting

TI__Mastermind 21590 points

Hello,

After looking at this on my bench, this is expected behavior.

Even though the BATFET is turned off, there are some internal circuits that are powered from the BAT pin.

Power management

Power management forum

BQ21061: BQ21061 charge done question