BQ25121A: BQ25121A Board Testing

Hi Hinal,

Can you explain your issue further? What is the voltage you are seeing on the BAT pin? Can you provide a waveform? 

Hi 

Okay, I am further explaining you my issue. 

I am testing my power section of BQ25121A. I am applying 5V at VIN, input Current limit 390mA (RILIM is 510ohm), Charging current 200mA (RISET is 1K) and termination current 10% of RISET. /CD pin is low by default, /MR, LSCTRL and RESET pin is floating. 

I am trying to get default output as datasheet shows. I am getting 2.5V default at SYS pin but I didn't get 4.2V default at BAT pin. I also cannot enable charging with I2C registers.

How can I charge my battery using BQ25121A?

Best Regards,

Hinal Tailor

Hi Hinal,

Can you provide a register dump and a schematic? What are you seeing on the battery pin that indicates that it is not charging (how are you determining it is not charging)? 

Hello

Here is my schematic diagram.

I didn't connect host with BQ25121A.

Thanks,

Hinal Tailor

Hi Hinal, 

From the schematic, it looks like do have everything setup correctly. 

Can you measure the voltage at the TS pin? Also can you please provide whether or not what voltage you see at the BAT pin and the voltage reading of the battery if you are testing with a battery?

Hello

I have connected 11k resistors (pull up and pull down) at TS pin between VIN and GND. I get 2.5V at TS pin. On BAT pin  I have measured 0V.

I tried to set charging voltage through I2C, BAT pin gives 4.2V. But we cann't set charging current through I2C. I am setting 50mA charge current using fast charge control register but I get 99mA charge current at BAT pin when VIN and Battery connected.

Best Regards,

Hinal Tailor

Hi Hinal,

If you can configure the device with I2C, are you able to provide a register dump? There will be helpful information in the status and fault flags even if you are using the resistor programmed settings.