BQ51050B: Output power issue !!!

Hello,

I will take a look at this more in lab tomorrow.. You may be seeing the battery detect waveform. Can you share any waveform images of the OUT pin in this case? How is the device charging if no battery is connected?

Thanks,

Nick 

Yes, I will setup and show you waveform when going to lab.
I have a note when testing:
When charging without battery connected, the output voltage is 1.6V
I connect battery to board, the output voltage raise to 4,2V
I continue disconect battery, the output still have 4.2V
Seem install battery when charging help BQ raise output right voltage when startup
I placed board on wireless charger dock all times of testing.

Hello,

With no battery this is an image of the BAT voltage waveform. Note that this can vary based on what transmitter is used.

When you are seeing 1.6V was this an average voltage reading? Please attach plots of Vrect and Bat pin during startup.

Thanks,

Nick

Thanks 

thanks
I have an issue with oscilloscope, so will try to send waveform asap
but i think 1.6V output not a average, because when install battery and uninstall, Vbat will raise to 4.2V

Hi
I cant setup to have a oscilloscope
but i have check a board cant charge when battery not connect, or connect with battery voltage about 0V

Hello,

We will need to look at the waveforms of the RECT and BAT pin to take this further. 

Best regards,

Nick

hi
i try to send you wave form as you request

Hello,

To see the full behavior of the transmitter the time base needs to be extended. In the image I attached we are using 2s/div.

Thanks,

Nick

hi

I send to you new waveform. It seem similar your waveform.

Vbat (pin4) without battery 

Vbat (pin4) with battery 

Hi
The remain issue is cant charge with battery at 0V.

Hello,

The bq51050b is able to charge a battery from 0V: 

Is there any protection circuit that could be interfering here?

Thanks,

Nick

hi
Please help to send me msg, i will send you a schematic to review.
Thanks.