BQ25895: BQ25895

Hi Vlad, 

Thank you for reaching out via E2E. Please see my comments below. 

Firstly, just to clarify will the 2 Li batteries be charged in parallel in your design? The BQ25895 is not designed to charge 2 cells in series. 

Regarding the other requirements you mention input voltage in the range of 5V to 12V is acceptable. The BQ25895 will function with an input across this voltage range, but the charger itself will not determine the voltage. That will depend on the input adapter being plugged in. 

Vladimir Demikh said:

The charging current of each battery must vary and can be 2.5A Max.

Maximum possible output current is 5A, so each battery being charged at 2.5A maximum is possible with BQ25895. Please be aware both battery cells will always be charged at the same current. For example, it will not be possible to charge one cell at 1A and the other at 2A at the same time. 

Vladimir Demikh said:

There is also a small microprocessor for determining and changing device modes

Microprocessor can be connected at SYS output. 

Best Regards,

Garrett 

Garrett thanks for the quick response! I mean 2 channel charger. Maybe one of them is made on BQ25895 for communication via USB, and the second is just a charger - as a slave. I think if both are connected to USB, there will be a conflict.
BR
Vlad

Hi Vlad, 

Vladimir Demikh said:

I mean 2 channel charger.

As in you mean you would use two BQ25895 devices?

The BQ25895 is designed to be controlled via I2C by an MCU host. It is also able to operate in standalone mode, but you will need to be okay to charge with default settings. Charging default settings is shown in table 8-4 on page 21 of the BQ25895 datasheet. 

BQ25895 will only communicate via USB to set input current limit using D+/D- lines. 

Best Regards,

Garrett 

Hello Garret, thanks for your answer. I came to the conclusion that I would use BQ25895 and BQ25896 chips in the charger for each of the channels. They have different addresses for the same communication bus. BQ25895 - will detect the VBUS type and the second chip will receive max. values for the charging current of your battery.
I received BQ25895EVM-664. During experiments with it, I discovered that when connecting to different USB adapters, their parameters are not always determined correctly. Sometimes I need to reconnect the connector in order for this parameter to be determined correctly.

Best Regards,

Vlad

Hi Vlad, 

Using BQ25895 + BQ25896 is a good solution to allow I2C communication to both devices. 

Vladimir Demikh said:

I received BQ25895EVM-664. During experiments with it, I discovered that when connecting to different USB adapters, their parameters are not always determined correctly. Sometimes I need to reconnect the connector in order for this parameter to be determined correctly.

Please help to share more details such as the initial adapter type detected and the correct adapter type in your experiments if you wish to further debug? The detection routine should always be the same. Therefore it is not expected for the result to change simply by reconnecting the same adapter. 

Best Regards,

Garrett