BQ51013B: Suggest an active Wireless Transmitter that will work with this receiver.

Hi James

The BQ51013 is listed as NRND, see product page.

But the BQ51013A is Active, see product page.

I would recommend the BQ51013B as a first choice, it is our latest design, see product page.

All TI transmitters are NRND, but any Qi certified transmitter will operate with the BQ51013B.

Do you need Qi certification for your RX?

Thanks, Bill.  We are currently using the BQ51013BRHLR.   Let me ask you this.   Have you successfully tested any competitor transmitters (that are active) with your reciever, BQ51013, and if so, can you please let me know what you have used that works?  I was testing an ST part which uses the same transmitter coil that we use it's essentially the same tank circuit.  It is also Qi compliant part.   However, we are having issue getting it to work consistently.   Receiver generates 5V for less than a minute and then drops off.  It's almost as if the transmitter is expecting Feedback from the receiver, doesn't get it, and then just gives up. 

Hi James

The BQ51013B has been tested with a large number of Qi Certified transmitters in different design, it has been on the market since 2013.  

What can you tell me about the ST transmitter you are using?

James Carter said:

Receiver generates 5V for less than a minute and then drops off.  It's almost as if the transmitter is expecting Feedback from the receiver, doesn't get it, and then just gives up. 

Bill J -- After the unit starts power transfer the TX is looking for the RX to send:

1.) Control Error Packets - sets the operating point, indicates error from target RECT voltage. Sent every 0.25sec must get good packet every 1.5 sec

2.) Received Power Packets -- reports how much power is received by the RX.  Will include power to load, efficiency, loss in metal and other.  Sent every 5 sec must get good packet about every 20sec.

If a good packet is not received the TX will shutdown and restart.  It is common for noise from RX load to cause communication problems.  

If the TX is trying to restart after it "gives up" it points to comm issue.

What does RECT look like when it stops?

STEVAL-WBC86TX is the wireless transmitter kit I am using.   The receiver goes to 5V for the first minute and drops off to mV afterwards.   It does not try to restart by itself.   You have to write an enable bit to it to have it attempt to restart.

You said you tested with a large number of Qi Certified transmitters;  are you able to say which ones you were successful in testing with and that are currently active to give me different options in case I have trouble getting the ST to work.   

One possibility that was brought up to me is the FOD flag is thrown, as the transmitter has not been tuned to the specific receiver, and that may be the reason why the transmitter shuts off after a short period.  I will need to disable it on the transmitter side and see if this fixes the issue.   Will test later today.

Thanks

Disabled EPT FOD on the transmitter side, and Receiver still cannot hold a charge.  Also, device should be able to start up using Ping method – where receiver coil is detected, and the only way I can take it to 5V temporarily is writing to the TX EN register.   This implies no communication between Rx and Tx.

I just received the Richtek RT3181A and it seems to be working without any issues so far.  No firmware configuration and automatically provides power under load.

A couple of things to try:

FOD

1.) If the Current Out of BQ51013B is below 100mA try increasing Ros (from RECT to FOD)

2.) If the Current Out is higher try increasing Rfod (FOD to GND), typical; value is 200 ohms can increase to about 235 ohms

Communications 

1.) The Comm 1 / 2, are typically 22nF but can be increased

2.) Comm caps are 10% to 20% of the series capacitor value but can be higher.