BQ51021: Developing with BQ24160

Mike Credelle

Part Number: BQ51021
Other Parts Discussed in Thread: BQ51013, , BQ24160, BQ500212A

We are developing a system with BQ24160 and BQ51021. We have USB going into the BQ24160 USB Input, and we have the output of the BQ51021 going to the VIN input of the 24160. Our wireless charging is only meant to trickle charge our system. We charge our 1400mah battery at 1A when using USB, but set the current limit of wireless charging to only 350mA. We just migrated our design from the BQ51013BRHLT to the BQ51021 so we could use the I2C interface to send data to our wireless charger. The system was stable using the BQ51013. We are getting the system up and running right now, but we are seeing the wireless charging connecting, the current goes to the limit then it decreases down to a low current in steps and then after a few seconds it re initiates back to the higher current and repeats. We don't want the current to constantly be ramping back to max current. Is there some i2c settings I should be looking at to better setup the device? The battery in this case is close to full, so it should just go to a low current output, equivalent to no load.

over 5 years ago

0 Mike Credelle over 5 years ago

Intellectual 300 points

We found that the BQ24160 is reporting VIN as a Weak Source in this register 9.6.2 Battery/ Supply Status Register (READ/WRITE) Memory location: 01, Reset state: xxxx 0xxx. The initial connection shows the connection as normal and then after a few seconds it would say weak source and then restart.

0 Bill Johns over 5 years ago in reply to Mike Credelle

TI__Guru 69966 points

Hello

Could be an FOD problem, try Removing R14 (20k) and increasing R16 & decreasing R15. The ILIM will stay same (R16 + R15), but R16 gets larger.

Also which RX coil are you using?

0 Mike Credelle over 5 years ago in reply to Bill Johns

Intellectual 300 points

I don't have access to a soldering iron at the moment, but since changing from the bq51013 we haven't changed the coil or the resistor values regarding ilim and fod. Any other way we can confirm this is the case?

0 Mike Credelle over 5 years ago in reply to Mike Credelle

Intellectual 300 points

I was able to modify our transmit power IC to disable FOD on the bq500212a, I did this by removing the resistor on the FOD and PMOD pins.

So it does appear to be FOD related, can you provide with me the document about tuning FOD on our RX board? Can you recommend some updated resistor values so I can try and order some to test?

Thanks

0 Bill Johns over 5 years ago in reply to Mike Credelle

TI__Guru 69966 points

Thanks for the update.

I need to discuss this with you offline, will contact you.

0 Bill Johns over 5 years ago in reply to Bill Johns

TI__Guru 69966 points

Hello

We are working this problem off line, will close this post.

Because of the Thanksgiving holiday in the U.S., TI E2E™ design support forum responses may be delayed from November 25 through December 2. Thank you for your patience.

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BQ51021: Developing with BQ24160