2024-04-11 02:37 AM
Hello everyone,
I'm reaching out to the community because I'm encountering an issue with a Wireless Charger board we designed, based on STWBC86 and a similar architecture to the STEVAL-WBC86TX evaluation board.
The main problem is the Power Transmitter locking up when the receiver is moved away.
As previously suggested by ST Employee @willzhou in a previous post, I have tried various attempts both with the STEVAL-WBC86TX and with my PCB, setting the "TX PING INTERVAL" parameter differently as you suggested, and I also tried clicking "TX PING HALF BRDG", but the issue has not been resolved.
Let me provide more detailed explanation of the issues encountered:
In addition, I have conducted further tests with default parameters on both boards (both the STEVAL Evaluation Board and my WBC86TX PCB), and I have recorded the following charts directly from WPSTUDIO's "Charts" feature, hoping they may be useful to your community in assisting me with resolving the issue:
FIG 1
FIG 1 depicts the operation of the STEVAL-WBC86TX: after a certain runtime (approximately 419 s), as indicated by the "Voltage" graph, the system transitions from 8V to 7V when the receiver is removed and returns to the PING phase.
Now, considering the following graph referring to my PCB (WBC86TX):
FIG 2
FIG 2: Initially, the board was functioning correctly as it transitioned from the transmission phase to the Ping phase. However, after a certain period (approximately 410s), the Voltage dropped significantly before returning to the Ping phase. After bringing the receiver close again, the system became stuck, as described earlier.
I hope this is sufficient to outline my issue.
2024-04-11 03:03 AM
Hi
Thanks for detail information.
1.Does STEVAL-WBC86TX and your WBC86TX board have any hardware different?
2.From you picture 2, TX input voltage drop from 8V to very low, TX chip have reset, also chip temp is higher than STEVAL-WBC86TX.Seems your TX have some damage.
4.What is input power limited current?
5.What is the volume of application? How about contract local FAE to check and gain more information.
2024-04-11 03:52 AM
Hi willzhou,
2024-04-11 04:17 AM
What is RX power, rx ouput and current? If you remove RX does RX absorb some power?
From your picture2, when you remove RX, TX chip temp rise from 50C to 70C. Seem TX chip consume many power inside, It is different with picture1.
How about you increase input limited current, Or set WBC86TX input voltage lower.
2024-04-12 03:44 AM
Hi willzhou,
I made a new acquisition with WBC86TX board for a total of 100 seconds, in which there is the PING phase for up to 15 seconds, then the RX is placed for up to 60 seconds, back to the PING phase and finally the RX is placed again.
The data was processed and plotted on Excel, where a maximum of 250 values can be entered for each graph.
I have attached to this message the Excel document containing the data and graphs. The graphs relate to voltage [V], current [mA], temperature [°C], RX power [mW] and TX power [mW].
The power curves show that the RX and TX power of the receiver is higher than that of the STEVAL-WBC86TX; also, I have tried reducing the supply voltage but the problem persists.
I have also tried increasing the maximum current that TX can draw to 1.5A, but the result is the same: if my PCB draws about 900mA during the transmit phase, the system crashes as soon as the receiver is removed and does not return to the PING phase.
2024-04-13 12:41 AM
Thanks for data
TX input voltage drop to 5V From your data, which is abnormal.
if you can send your TX device to ST office, and i can do some test with your board.