about BQ51050 Termination application

eiven wu

Prodigy 215 points

hi:

i use the bq51050 .

the conditions are below:

1.Charging current is 150mA

2.The RX AND TX distance is 15mm.

when i charging the battery,i had auto recovery in TX sometime,

I adjust the termination resistor from 5k ohm to 1k ohm.

i can not see the phenomenon.

i check the BQ51050 Datasheet.it means"Note that this packet does not turn off the transmitter and is only used as an informative indication of the mobile device’s charge status".

is it correct?

over 9 years ago

0 Dick Stacey over 9 years ago

TI__Genius 14890 points

Eiven,

Communication at 15mm is very difficult. I expect that the communication is not working effectively in all cases. At that point, power transfer will cease.

Can you explain more what you mean by "auto recovery"?

Regards,

Dick

0 eiven wu over 9 years ago in reply to Dick Stacey

Prodigy 215 points

Hi Dick

please refer the below figure:

you can see what's auto recovery.

0 eiven wu over 9 years ago in reply to eiven wu

Prodigy 215 points

hi Dick

Do you have any feedback for this?

thanks.

0 Dick Stacey over 9 years ago in reply to eiven wu

TI__Genius 14890 points

Eiven,

Thank you for the plot showing auto recovery. I fully understand now.

I suspect that at this distance, the communication is failing. Once it fails, the transmitter will try and reestablish communication and that's when the auto recovery occurs.

What value are the capacitors on your COMM pins? Perhaps increasing the value could help with the communication at the long distances you are using.

In my lab, I use an Avid Technologies tool called a "Qi Development System". It attaches to your USB port and when placed next to the TX / RX junction can "listen in" on the communication. It will indicate what messages are passing properly and what they are.

Regards,

Dick

0 eiven wu over 9 years ago in reply to Dick Stacey

Prodigy 215 points

Dear Dick

thanks your feedback.

The COMM is standard value 22nF.

I will try to increase the value.

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about BQ51050 Termination application