A question about nrF52832's DC/DC and LDO

RE: A question about nrF52832's DC/DC and LDO

Ole Bauck — Wed, 24 Feb 2016 16:42:11 GMT

You're welcome :) If you liked the answer please mark it as correct (check mark to the left below the arrows).

RE: A question about nrF52832's DC/DC and LDO

wenxue — Wed, 24 Feb 2016 15:07:49 GMT

Thanks for your explanation.

RE: A question about nrF52832's DC/DC and LDO

Ole Bauck — Wed, 24 Feb 2016 10:06:09 GMT

If DCDCEN = 0, system will only use LDO (the hardware for DC/DC may not be available). The DC/DC should automatically turn off when CPU is sleeping and radio is off. The errata "DCDC does not automatically switch off in System ON IDLE" is only present on engineering sample A and B, it is fixed on the newest versions of the chip. See this tutorial for how to workaround this issue. You enable DCDC with

sd_power_dcdc_mode_set(NRF_POWER_DCDC_ENABLE);

RE: A question about nrF52832's DC/DC and LDO

wenxue — Wed, 24 Feb 2016 00:41:38 GMT

Thanks for your answer. If DCDCEN=0, system only use LDO,is it right?

You mention "it is not efficient to keep it on when the CPU is sleeping and the radio is off", I found in Errata "DCDC does not automatically switch off in System ON IDLE",does it mean DCDC shoud automatically switch off when CPU is sleeping and radio is off. I have another quesiton, I want to test TX/RX peak current compared with LDO and DCDC, how to achieve it? In ble_app_pwr_profiling example of nRF5_SDK_11.0.0-2.alpha_bc3f6a0, I don't find any setting of DCDCEN, does it mean it only use LDO? Looking forward for your answer.

RE: A question about nrF52832's DC/DC and LDO

Ole Bauck — Tue, 23 Feb 2016 15:52:05 GMT

If you set DCDCEN = 1, LDO will be used when the current is low. The DC/DC converter needs some current to be operational, therefore it is not efficient to keep it on when the CPU is sleeping and the radio is off. The system will use the DC/DC only when it is beneficial.