nrf52840 DK high voltage mode via J2 USB

[John Ivan Fox]

Hi,

I would like to operate the board in high volt mode via the J2 input and the SW9 should be in the VDD position.

I have set the REGOU0 to 0xFFFFFFFD but when after measuring the volts still at 2.9V. However, the board is powered via the J3 the VDD GPIO pin has the 3.3V output.

Is it possible to supply the board in high voltage mode via the J2 or does the board have to be powered via the J3 USB?

[Jared]

Hi,

The DK has to be supplied by the J3 USB port:

The nRF52840 SoC has a high voltage buck regulator that can support up to 5 V input. In the VDD position, the SoC is powered either from the onboard buck regulator, coin cell battery, or external supply (P21). In the Li-Po position, the high voltage regulator of the SoC is supplied directly from the Li-Po battery connectors (J6 or P27). In the USB position, the USB high voltage regulator gets power from the nRF52840 USB connector (J3).

When the high voltage regulator is used, the VDD_nRF voltage can be set by the firmware of the SoC. To make sure the rest of the Development Kit (DK) has the same voltage level, the VDD of the DK is sourced by a regulator following the VDD_nRF voltage when the high voltage regulator is used.

regards

Jared