BQ24095: BQ24095DGQR

Keyur Parikh

Part Number: BQ24095

Tool/software:

Hello TI Support,

We have been using the BQ24095DGQR charging IC in our various applications from last 2 years. In all applications, this ic working fine. In charging condition its temperature is 30'C to 35'C.

But Now in new design this IC temperature rise 85'C to 95'C during charging. So we are not sure what is the issue. So could you please help to solve this issue.

Please find below design. Let me know, if require any others details. Please look it here and reply asap.

Regard

Keyur Parikh

over 1 year ago

0 Michael Emanuel35 over 1 year ago

TI__Mastermind 40525 points

Hello Keyur,

What is the applied input voltage and battery voltage? What is different between the old design and the new design?

Regards,

Mike Emanuel

0 Keyur Parikh over 1 year ago in reply to Michael Emanuel35

Prodigy 50 points

Hello Michael,

Input Voltage is 5.08V and Battery Voltage is 3.7V. There is only controller and PCB size & layout changed in new design.

Regards

Keyur

0 Michael Emanuel35 over 1 year ago in reply to Keyur Parikh

TI__Mastermind 40525 points

Hi Keyur,

Having a programmed charge current of 1 A with a 1.38 V differential between the input and output leads to 1.38 W of power lost. Can you try lowering the input voltage or lowering the charge current?

Regards,

Mike Emanuel

0 Keyur Parikh over 1 year ago in reply to Michael Emanuel35

Prodigy 50 points

Hi Mike,

We have tried by reduce the current limit resistor on Iset Pin but there is no any impact on charging current and till IC is heated.

With reduce voltage, Our charger voltage is fixed. We are not able to change it.

Regard

Keyur

0 Wyatt Keller over 1 year ago in reply to Keyur Parikh

TI__Guru** 105760 points

Hello Keyur,

Can you share what resistance values you have tried with ISET? This should limit the charge current and prevent overheating. If layout was changed significantly it can also impact heat dissipation.

Sincerely,

Wyatt Keller

0 Keyur Parikh over 1 year ago in reply to Wyatt Keller

Prodigy 50 points

Hello Wyatt,

I have mounted the ISET resistor 2.2K for 250mA current. But as mention pervious, there is no any impact on current flow. Regarding Layout, I will change it if required. But currently i want any other solution to solve this issue. Meaning if any suggestion, like by pouring solder at bottom side. Which i have already did it but there is no any impact on hitting. Please give suggestion.

Regards

Keyur

0 Michael Emanuel35 over 1 year ago in reply to Keyur Parikh

TI__Mastermind 40525 points

Hi Keyur,

Someone will get back to you by Wednesday. We are observing Labor Day.

Regards,

Mike Emanuel

0 Michael Emanuel35 over 1 year ago in reply to Michael Emanuel35

TI__Mastermind 40525 points

Hi Keyur,

For debugging purposes, please lower the input voltage closer to the battery voltage to see if the programmed charge current is realized.

Regards,

Mike Emanuel

0 Keyur Parikh over 1 year ago in reply to Michael Emanuel35

Prodigy 50 points

Hello Mike,

We have did it as mention above by change the series schottky diode. Yes, With this change hitting is reduce. Parallel, i am working to change the layout as per the datasheet. I will send the layout file for your review, Please allow me sometime for update the layout.

Regards,

Keyur Parikh

0 Michael Emanuel35 over 1 year ago in reply to Keyur Parikh

TI__Mastermind 40525 points

Hi Keyur,

If lowering the input voltage realized the current properly, you will need to provide a lower input voltage. The linear charger is acting like an LDO. Any power lost is dissipated as heat. For example, if you have a 4V/1A battery with a 5V input, 1V*1A will be dissipated as heat. However, lowering the input voltage to 4.1 V will only dissipate 0.1 W.

Regards,

Mike Emanuel

0 Keyur Parikh over 1 year ago in reply to Michael Emanuel35

Prodigy 50 points

Hi Michael,

Got it your point. But this design used in multiple product with same charger. So that is make sense same design should be work in all product. Hope you are understand my point. Anyway please review below layout file and let me know if required to change any point.

Regards

Keyur Parikh

0 Michael Emanuel35 over 1 year ago in reply to Keyur Parikh

TI__Mastermind 40525 points

Hi Keyur,

Please send the gerber files for analysis of the layout. What has changed since the last designs?

Regards,

Mike Emanuel

0 Keyur Parikh over 1 year ago in reply to Michael Emanuel35

Prodigy 50 points

Hello Mike,

Pervious file , we have not connected thermal pad to GND plane. Now we have connected it with GND. Please find attached gerber for review and reply us asap.

Gerber file.rar

Regards

Keyur Parikh

0 Michael Emanuel35 over 1 year ago in reply to Keyur Parikh

TI__Mastermind 40525 points

Hi Keyur,

It looks to me on the bottom layer that the GND return path from the left side of the chip to the right side of the chip is not connected very well. Specifically the C3 C4 GND is not connected to the IC GND very well. It goes up to the top of the board, through two vias, and then snakes through a narrow return path. Please make sure your power GNDs are adequately connected.

Regards,

Mike Emanuel