LDO vs DCDC (nRF51822)

[kvrb]

Hi,

I am using simple ADC peripheral to read internal battery voltage(standalone). I am using two custom nRF51822 boards. One of the nRF51822 board is made by nRF51822 Schematic with Internal LDO (Module’s Default) and other one nRF51822 Schematic with Internal DC/DC Converter mode.

The example code is working fine in nRF51822 Schematic with Internal LDO (Module’s Default) and There is no output in nRF51822 Schematic with Internal DC/DC Converter mode.

What is issue in nRF51822 Schematic with Internal DC/DC Converter board..??

[bjorn-spockeli]

The only difference between the nRF51822 reference circuit with the internal LDO setup and the reference circuit with the DC/DC converter setup is that the DC/DC setup includes L5(15nH), L4 (10uH) and C12(1uF), which are components required by the DCDC.

The DC/DC setup can run both from the internal LDO and the DC/DC, in fact it will use the internal LDO by default. The DCDC must be explicitly turned on in code by calling the sd_power_dcdc_mode_set() function, i.e.

sd_power_dcdc_mode_set	(NRF_POWER_DCDC_ENABLE)	

You code should run just fine on both the board based on the LDO setup and the one based on the DCDC setup.

Best regards

Bjørn