NRF8001 DC/DC converter enabled

[Hisham]

Hello,

This is the first time i use NRF8001 chip, i was reading the ic manual nrf8001_PS_v1.1.pdf (see attached file). It was written that in case i used DC/DC converter to step down the voltage it can reduce the power consumption up to 20%. (page 45) Also in the recommendation for low power operation they recommend to use external 32.768KHZ crystal instead of 32.768KHZ internal RC oscillator. (page 45)

But in order to enable the DC/DC converter the NRF8001 should not be configured to 32.768KHZ crystal, instead it should used the internal oscillator (as table page 30).

So in case i decided to enable the DC/DC converter, i should use the internal oscillator.

My question is, the reduction in power consumption due to the use of DC/Dc converter takes into account the effect of the use of RC oscillator and it results up to 20% reduction in current, or the usage of the internal oscillator will result in more current dissipation and the total current reduction will be reduced to a value less than 20%?

Thanks, and regards Hisham

nRF8001_PS_v.1.1.pdf

[Ole Morten]

The 20 % reduction is the reduction of the peak currents, and since the clock source used doesn't affect the peaks at all, this is independent of clock source.

However, the average current consumption with a BLE device is also affected by the consumption outside the peaks, so in practice you'll see less reduction in the average current consumption than you will on the peak currents. In the PS, this is pretty nicely described in chapter 13, so I'll recommend you to take a look on it.