nrf52:Use DC/DC regulator to save power consumption

nrf52832 has two power mode.LDO mode and Switching power mode.To use Switching power mode will need to add Inductor  between the DEC4 pin and DCC pin, and use software to change mode.

in softdevice :

	sd_power_dcdc_mode_set(NRF_POWER_DCDC_ENABLE);

view raw gistfile1.txt hosted with ❤ by GitHub

It can save 5~6 uA around 17% of current on ble_template project








Ref:
       1. LDO vs Switching power
       2. nRF52 Online Power Profiler