This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ51013B power down mode and detection signal

Dear TI Wireless Power Application Support Team,

Currently we have a wireless single-cell Lithium battery charger system based on a BQ51013BRHLT device.

Our TX and RX coils are well tuned, and our charger performance is quite good.

We use the RECT output as a means to alert the host microcontroller that the device is on the charger, and we disable most of the system.

Our problem is when BQ51013BRHLT is put in powerdown mode. We use battery charger’s “battery full” signal to power down BQ51013BRHLT by pulling <EN2,EN1>=”11” to stop the charging current from the receiver.

However, when the BQ51013BRHLT  is left on charger, disabled, we noticed that we still see transient OOK type modulated waveforms on the RECT out - I believe this is due to routine data from the TX coil ?

These pulses mess up our firmwire, signalling that the charger is re-applied.

My two questions are:

1)      Is there a way to stop RECT toggling while on the charger and device is turned off ? is this something expected ?

2)      Is there any other output pin (other than RECT) from the device that we can use to detect that the device is on the charger when it is on, that is more robust  ?

Thanks for your help!

Regards,

Bertan

  • This is a difficult problem.  The TX will ping the RX to verify that it has not been removed and another units placed on the pad.  Turning off the ping would prevent detection of changes on the charging pad.

    This ping will provide enough power for the RX to turn on and reply and send charge complete or other end power transfer message. RX can only communicate with the TX during this ping or during power transfer.

    I will check on a few things and send more info tomorrow.