NCS v2.6.0 | nRF 52840 | Custom Board
Hi,
I was looking for information on the efficiency of the DC/DC high voltage mode because the current consumption I'm seeing doesn't make sense to me. I measured the current with a PPK2 on 2 of our custom boards, one that runs our application and is fully populated and one that runs minimal firmware (essentially does nothing but enter idle mode) and is largely depopulated (all external ICs are removed and only the passives remain). Both board / FW configurations show a similar increase in current consumption with an increased voltage supply to Vddh. My understanding is that the DC/DC regulators get more efficient the larger the voltage drop is, and the current measurements I'm seeing seem to conflict with that. In the final form, the device will get power to Vddh directly from a LiPo battery (3.0 -> 4.2 v) so that's the range I tested.
I enable DC/DC HV mode with essentially the same code that the nRF 52840 dongle uses:
#include <zephyr/init.h>
#include <hal/nrf_power.h>
static int board_myboard_nrf52840_init(void)
{
if ((nrf_power_mainregstatus_get(NRF_POWER) ==
NRF_POWER_MAINREGSTATUS_HIGH) &&
((NRF_UICR->REGOUT0 & UICR_REGOUT0_VOUT_Msk) ==
(UICR_REGOUT0_VOUT_DEFAULT << UICR_REGOUT0_VOUT_Pos))) {
NRF_NVMC->CONFIG = NVMC_CONFIG_WEN_Wen << NVMC_CONFIG_WEN_Pos;
while (NRF_NVMC->READY == NVMC_READY_READY_Busy) {
;
}
NRF_UICR->REGOUT0 =
(NRF_UICR->REGOUT0 & ~((uint32_t)UICR_REGOUT0_VOUT_Msk)) |
(UICR_REGOUT0_VOUT_3V0 << UICR_REGOUT0_VOUT_Pos);
NRF_NVMC->CONFIG = NVMC_CONFIG_WEN_Ren << NVMC_CONFIG_WEN_Pos;
while (NRF_NVMC->READY == NVMC_READY_READY_Busy) {
;
}
/* a reset is required for changes to take effect */
NVIC_SystemReset();
}
return 0;
}
SYS_INIT(board_myboard_nrf52840_init, PRE_KERNEL_1, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT);
Once the application has booted I've used nrfjprog to memrd the relevant POWER registers and confirmed that DCDC mode is enabled and REG0 is enabled.
Here are the measurements I've taken:
Is the increased current consumption after ~3.6v expected? Thanks for any help!
