High voltage mode uses the main regulator (VREGMAIN), the high voltage regulator (VREGH), and the radio regulator (VREGRADIO).
All regulators operate in LDO mode by default. DC/DC mode is enabled independently for each regulator using VREGMAIN.DCDCEN (Retained), VREGH.DCDCEN (Retained), and VREGRADIO.DCDCEN (Retained).
When configured as shown in the following figure, nRF5340 enters high voltage mode. Here all three regulators are in DC/DC mode. An external LC filter is required for each of the regulators in DC/DC mode. The inductor is not needed when the regulator is exclusively in LDO mode.
Operating a regulator in DC/DC mode reduces the overall power consumption due to higher efficiency than in LDO mode. Regulator efficiency in DC/DC mode varies depending on the supply voltage and the current drawn from the regulators.