BQ24072: Not working in charging condition.

Hi Jagan, 

I am looking into if the font style difference has any significance. In the mean time can you please provide further detail into the issue you are seeing? 

Does the device simply not charge? Is there any difference in /CHG and /PGOOD status indicators between the working and non working device?

Best Regards,

Garrett 

Hi Sir,

We have facing 2 different issues on Newly purchased BQ24072 IC.
      1. Battery is not charging
      2. IC is not working at USB condition.

Below I have attached the pin states for both the issues and our schematic for your reference. We facing these issue in only new IC's. Please check and update us why these issues happen.

Hi Jagan, 

Thank you for providing further details on issues you are observing. We are conducting additional research and will get back to you as soon as possible. 

Best Regards,

Garrett

Hi Sir,

More than 20 ICs failed in charging condition, all newly purchased.
So please check and update us as soon as possible

Thanks,
Jagan K

Hi Jagan, 

Apologies for delay. We were still working to conduct research comparing information on old working unit and new issue unit. 

Firstly, the difference in font is because the parts were manufactured at a different site from each other. 

Available information showed there should be no difference between older material and new material.

Has the design (schematic or layout) changed for units with new material compared to older material? Are you able to perform an ABA swap to verify an existing working unit can work on the board of an issue facing part? 

Best Regards,

Garrett 

Hi Sir,

1.There is no design changes in our unit.
2. Yes, we tried the swap case, the issue facing unit is working fine after installing the old IC.

Would you do us a favor?
Do you have testing support in India, If there, We will ship our issued ICs to there, It will help you to debug and we also know the issue.

Thanks,
Jagan K

Hi Jagan, 

Thank you for your comments. 

Unfortunately we do not have testing support available in India. 

For the swap case did you also swap a not good IC onto a previously working board? 

On a not working unit have you checked if other pins are not at expected voltage? For example, is /CE pin = GND, are EN1 and EN2 at expected logic levels.

Regards,

Garrett

Hi Sir,

We tested to swap the issued IC to a working good unit, But facing the same issue.
We have been using your IC for more than 5 years, but we have facing issues like this the 1st time. We are suspecting the newly purchased IC. So please check your end Why this issue happened in the New IC and let me know if this is your manufacturing IC.

Thanks,
Jagan k. 

Hi Jagan, 

Thank you for your answer and confirming issue only follows the IC not the board. 

Production data for the lot of the issue facing unit top marking you provide shows nothing abnormal and we have had no other reports of this type of issue with BQ24072. 

Therefore we are attempting to check all possibilities of how IC may have issue. Have you by chance changed PCB vendors recently? Additionally, can you help to clarify why the layout in the 2 images you provide appears different even though you previously stated the design is unchanged?

Regards,

Garrett

Hi Sir,

I added the image just for your reference, but we tested both ICs in the same layout.

Last year we built 25k units but we didn't face an issue like this so we have a strong opinion on our board and issues are facing this lot ICs only.

Currently, we are in mass production, in that we facing 20-30/1000 unit are issues in IC, but other units are working fine at the same lot, we also checked the issued units by replacing the other new IC and it works well, so how would we suspect the board?

It is a critical issue for us, So we plan to ship the issued ICs to you, Please support us in solving this issue and share your lab address.
I have attached the DOC of the purchased issue facing ICs.

DOC_BQ2072.pdf

Thanks,
Jagan K.

Hi Jagan, 

Thank you for your clarifying comments as well as providing number of issues facing units out of total quantity ordered. 

It is understood this is a critical issue. I am checking on best path forward for this case and will get back to you as soon as possible. 

Best Regards,

Garrett 

Hi Sir,

The IC failure count is increasing day by day, Till now 20-30 ICs have failed under different projects in charging condition at the 1st time, the device was powered up. Please take these failed ICs as an RMA to check the issue.

Thanks,
Jagan K.

Hi Jagan, 

Jagan K said:

Please take these failed ICs as an RMA to check the issue.

Before we can reach this step please help to answer our open questions. 

1) On a not working unit have you checked if all pins besides OUT and BAT are at expected voltage? For example, is /CE pin = GND, are EN1 and EN2 at expected logic levels.

2) Have you by chance changed PCB vendors recently? You responded you built 25k units last year, but can you please confirm if anything has changed in production flow between then and now. 

Jagan K said:

Till now 20-30 ICs have failed under different projects in charging condition at the 1st time, the device was powered up

Thank you for sharing test condition. To confirm all failing ICs do not work when powered by USB input for first time, is that correct? 

Regards,

Garrett

Hi Sir,

I have answered your queries below.

1. We have checked all the pins of the issued IC and compared the voltage between the (battery not charging) issued IC and the working Good IC, below i have attached the voltage table for your reference. Please check
2. We didn't change the PCB vendors and the layout also has not changed.
3. Yes, It is correct all the failing ICs do not work when powered by USB input for the first time.

Thanks,
Jagan K

Hi Jagan, 

Thank you for the response and providing voltage table for us to review. 

The observed voltage difference at BAT pin for "5V USB Only" case may indicate the reason for not being able to charge.

When no battery is connected the BQ24072 performs battery detection routine where small amount of current is briefly applied and expectation is VBAT will rise to full charge voltage of ~4.2V. This expected behavior is shown in datasheet figure 10-3. 

If possible are you able to quickly check on an issue facing IC if /CHG will go low and device charges if you connect 5V USB and a battery or battery simulator with initial voltage < 2V? 

Best Regards,

Garrett 

Hi Sir,

I have tested the issued IC with USB supply and battry less than 2V as per your suggestion and attached the voltage table below, please check.

The count of issue IC increased everyday in production boards, It is a critical issue for us, So please help us to solve this, and update us about taking failed ICs as RMA.

Thanks,
Jagan K.

Hi Jagan, 

Thank you for confirming /CHG status indicator will go low on an issue facing device when battery voltage is low enough. 

Can you please help to provide your email so we can further discuss details on returning failed ICs for further analysis? I have sent you a friend request through the E2E forum so you can share via private message if you prefer not to share on this public thread. 

Best Regards,

Garrett