Will adding a 1.8V buck converter extend the battery life of the beacon?

RE: Will adding a 1.8V buck converter extend the battery life of the beacon?

Bjørn Kvaale — Tue, 17 Oct 2017 10:47:50 GMT

Answer to 1: see these links (link1 & link2).

Answer to 2: Yes, that is correct. Just make sure that the input voltage is within the supply voltage boundaries of the nrf52832.

RE: Will adding a 1.8V buck converter extend the battery life of the beacon?

Matthew K — Mon, 16 Oct 2017 15:05:34 GMT

Wow! Great detailed answer, Bjørn!

You got me; I'm not trying to give power to multiple things that require 1.8V, e.g. an accelerometer.

I was trying to squeeze the last drop from the battery :D

I checked the Fig. 2, DC/DC regulator setup from your link and the schematic of PCA20014.

The PCA20014 mounted L2 and L3 at the DCC pin, just like Fig. 2.

These are my final questions;

1.How can I enable the DCDCEN register

if the supply voltage (VDD_nRF) is between 1.8~3.6V and inductors and capacitors are connected between DCC and DEC4

to use the internal DC/DC regulator?

While browsing various BLE peripheral examples, I don't see any codes related to configuring the DCDCEN register.

After getting your help, I will squeeze every last drop!

2.Due to the internal DC-DC converter, I don't have to care about the fluctuating supply voltage (VDD_nRF), right?

RE: Will adding a 1.8V buck converter extend the battery life of the beacon?

Bjørn Kvaale — Mon, 16 Oct 2017 11:27:01 GMT

The nrf52832 already has a built-in DC-DC converter. Therefore, using an extra DC-DC converter between the battery and the nrf52832 most likely will not lead to less current consumption. In addition, since the analogue parts of the nrf52832 (e.g. radio, etc.) require 1.3 V, you would need to use your DC-DC converter which converts the 3 V coin cell battery voltage down to 1.8 V plus the built-in DC-DC converter on the nrf52832. Using two DC-DC converters in series will most likely not lead to less current consumption.

If I were you, I would either do some current calculations or ideally measure current on your custom board: one scenario that uses the 3 -> 1.8 V DC-DC converter and one that does not. Most likely, adding a 3->1.8 V DC-DC converter will not lead to less current consumption and therefore will not increase the coin cell battery life.

In some situations, it can be useful to add a DC-DC converter in front of the nrf52 (e.g. giving power to multiple things that require 1.8, e.g. an accelerometer). But this is most likely not one of those cases unfortunately.