Hello,
I am working with an STM32WBA65RI that is on our custom board, and working to reduce our power usage. Along this journey I found the issue with the HAL_PCD_MspInit() / DeInit() where the logic for the RCC PWR was inverted, which was another post I made.
On our current hardware, I am noticing a large jump in current draw at the function call for __HAL_RCC_USB_OTG_HS_PHY_CLK_ENABLE() in HAL_PCD_MspInit().
Just prior to the function call, the board is drawing 7.5mA, and immediately following the call it is drawing 33.09mA.
I also tested this against the NUCLEO-WBA65 board, measuring across JP2, and see a jump from 3.05mA to 11.99mA, which seems more reasonable, albeit still quite large (according to DS14736, the max power draw from the OTG_HS PHY should be 5.7mA):
For reference, our board has the following power setup:
- VBAT is 3.9 (for this test I am using a power supply). This feeds a PMIC (MAX77658). The PMIC takes the 3.9V in and creates a 3.3V using an internal switching regulator. This 3.3V is used to power VDDUSB for the STM32WBA65. We then set up the PMIC's internal LDO1 to drop to a clean 1.8V, which is used to power the STM32WBA65.
- I am measuring the current on our board by connecting the 3.9V from the digital power supply through a Joulescope to the VBAT line.
- Here's the measurement as I step over the function call __HAL_RCC_USB_OTG_HS_PHY_CLK_ENABLE() in HAL_PCD_MspInit():
- The clock source for both OTG_HS PHY clock and SYSCLK is 32MHz HSE. USB is configured as Device_Only, Activate_SOF and Activate_VBUS are both disabled.
- GPIOs are set to analog mode except for USB pins, RCC_OSC pins, DEBUG pins, and I2C pins (used to configure the PMIC). There are three GPIOs set to 0, as they are intended to control power switches to peripherals on another I2C interface - which is not even enabled in this project.
- RCC setup is using SMPS supply, with HSE and LSE enabled, both as Crystal / ceramic resonator.
I've not been able to come up with an apples-to-apples comparison with the Nucleo board since I don't have a great way to separately provide 1.8V to VDD and 3.3V to VDDUSB - if you have ideas on how to do this, I'd appreciate it!
I've attached the example project that I'm working from.
In any case, I'm trying to understand why the power draw explodes this way, so any thoughts you have would be appreciated.
Thank you,
Jonathan
