USB PD Part selection

[NajeemSyed]

Hello,

I'm working with the STM32U575VGT6 as my primary MCU and need a USB-C DRP PD IC. I'm considering the TCPP03-M20 or STUSB1600AQTR. My question is, when the PD operates in sink mode (during charging), we intend to turn off all power supplies, including the MCU. Is it possible to use these ICs in sink mode without the MCU? Additionally, we need the PD to act as a source when external peripherals are connected to this board through USB-C.

[NajeemSyed]

Hi Pascal,

Based on the DK, we have designed our own PD circuit for our custom board. Please cross-verify the schematics and let us know if we need any changes?

[PPAIL.1]

Hi NajeemSyed,

1- osKernelStart is starting declared threads. Nothing below is executed.

You have to declare a new thread, start it and work independently in this new thread for your own application.

2- Schematic review

- You can adjust R59 (Current sense) depending on the maximum current your application will sustain to gain in precision. Ensure you keep : max_application_current * R59 * 42 < 3.3V. (42 is the TCPP analog gain, 3.3 is the maximum ADC voltage). 

- I would advise to review your bridge resistors R60/R62, and R61/R63 :

R60 and R61 should be higher than R62 and  R63 , in the X-NUCLEO-DRP1M1 : 200k and 40.2k in some Nucleo and DK we use 300k and 50k  to reduce losses.

The B-U585I-IOT02A can be a another good example.

Best regards

Pascal

[PPAIL.1]

Correction about my last message:

2-- You can adjust R59 (Current sense) depending on the maximum current your application will sustain to gain in precision. Ensure you keep : max_application_current * R59 < 42mV. (42mV is the OCP threshold). 

[NajeemSyed]

 

Hi,

Thanks for your reply. I have following queries regarding schematics:

1. I have used 200K/40.2K for VBus ADC sense and connected this to STM ADC Pin. 

2. I have also connected Pin IANA of TCPP03 (USBPD IADC) pin to STM ADC. 

3. What should i connect in PA9 of STM32U575. (USB_OTG_FS_VBUS). Our device is battery powered device and USB is hot swappable dual role application. Should i connect the Vbus or Vprov or Vcons here?

4. The EN pin (pin 20) of TCPP03 is hard wired to 3.3 V through a Pull Up (R54). (Always high) instead of GPIO. But while using a Development Board we face a issue that it is sometimes not detecting the USB 

[PPAIL.1]

Hi NajeemSyed

1. 200k/40.2k for Vbus ADC is ok

2. Iana to ADC is ok (Not mandatory)

3. This pin is not related to USBPD.
The USBPD application needs at least Vbus connected to an ADC.

Others (Isense, Vprov, Vcons) are optional at the X-Cube-TCPP point of view and depending on your application needs.

4. You can connect the EN pin of TCPP03 to 3.3V

(There is a warning in the X-CUBE-TCPP platform settings but it is ok)
The issue you are facing is USB or USBPD related ?

Best regards

Pascal

[NajeemSyed]

Thanks for the response. 

we have few queries:

1. For USBPD based Batttery power applications, what should we connect on STM32U575 MCU PA9 pin (USB_OTG_FS_VBUS)

2. When we are testing the same firmware with having EN pin pulled up, we are facing some issues while running. Like after 5-6 operation cycles, it's not working until MCU is reset.