Hi, I built a small USB-C PD trigger and power monitor using an ESP32 and the AP33772S. I designed and assembled the PCB and I’m now trying to get USB-PD working.

• When I plug in a USB-C PD charger (Apple 20W A2246), the board does not turn on — the TX LED stays off and PD does not start.
• But when I use a normal (non-PD) charger, everything works: the LED turns on, ESP32 runs, I2C works, and serial output shows voltage/current.

Example log:

I2C: 0x3C 0x40 0x52 0x70 | VBUS=5026mV | INT=0 ALT=1 CG=0 | AP33772S STATUS=0x0 V=5040mV I=96mA

So 5V is present and CC orientation is detected, but PD negotiation never completes and no PDOs are read.

I’m using this library:
https://github.com/CentyLab/AP33772S-Cpp

I’ve tried different PD chargers and cables with the same result. I’m not very experienced with electronics, so I suspect a hardware issue (CC pins, EN pin, VBUS sense, etc.).

I’ve attached my schematic. Could someone please check it and tell me what I might be doing wrong?





Thanks for any help.

 

On CC1 / CC2 you have R56 = 5.1 k, R55 = 5.1 k. BUT they are tied through 0 ohm resistors and protection diodes, and not clearly hard-pulled to GND at all times. AP33772S does NOT provide the Rd resistors internally. Get rid of the 0 ohm. And connect like this.
CC1 - 5.1k -GND
CC2 -5.1k-GND