P9242-R Wireless Charger not working


I'm having trouble with my P9242-R based wireless charger that I designed for a client. The chip in question is this:


I used the exact same circuit given in the official datasheet. Followed the layout guidelines.

The issue I'm having is that the board powers on, green LED flashes for a second, then the red LED starts flashing at 4 Hz indicating a fault.

I tried getting the status register value via i2c bus and it seems like it's indicating a "over temperature fault". The problem is I kept getting different values while trying to read the status register via i2c. But the number "6" kept coming up which might indicate the temperature fault according to the datasheet.

Upon further investigation, I also found the Q6 FET to be insanely hot to the touch. I replaced the FET, and yet the new FET continued to be super hot to the touch. I checked for shorts but couldn't find any. The Q6 FET is indicated in the picture below.

Any help would be appreciated! Am I missing something?

Parents Reply
  • Hi Cwern,

    1. What is the Rx used to test the Tx?  what is the load current of the Rx when the issue occurs?
    2. What is the Tx coil part number?
    3. Can you measure the temperature at the thermistor when the over temp shutdown is triggered?
    4. Can you probe below signals before the power transfer until the over temp is triggered?

                    TP314(TS), TP306 (LDO33); TP505 (coil1); Input current of the Vin+ and Vin+

    1. I can't open the layout.  Can you send me the PCB layout in PDF (similar to the section 5_Board layout in the REN P9242-R EVK User Manual)?