QDEC current on nrf 52805

[yuval]

Hi,

I'm using the NRF52805 with the QDEC.

As far as i saw in the datasheet, the QDEC suppose to take about 5uA But when i operate it is takes about 500-700uA !!

The current don't change even if i change the samples time or report time.....

The decoder working fine except the current which is too high !!

Any idea why and how to solve it ?!

B.r,

Yuval.

[Einar Thorsrud]

Hi,

The specified run current for the QDEC is for the QDEC peripheral itself, and does not includ other things like clocks and regulators (particularily the HF clock). You can look at the current consumption scenario for a TIMER running at 1 MHz, and those numbers should be comparable for the total current consumption you will get for the QDEC.

[yuval]

Hi,

I removed the QDEC and now doing the decoder stuff in software using toggle GPIOTE events

We connect analog encoder (A & B) to the NRF52805
We need assitantant about the internal pull up resistors on GPIOTE toggel event.
We have situation when we active the internal pull up resitors (the 1M resistors are not assembeled) the current consuption is getting high while in sleep mode.
When the encoder is 1,1 - we get the lowest power consumption,
When the encoder is 1,0 or 0,1 - We get middle power consumption.
When the encoder is 0,0 we get the highest power consumption (more then 500uA additional to encoder in 1,1)
We want to know if there is any way to reduce the power consumption.

Please advise

[Einar Thorsrud]

Hi,

The internal pull resistors are typically 13 kΩ. You could use external pull resistors instead, with higher esistance (weaker pull).

Alternatively, on the QDEC peripheral if you decide to use that anyway, the LED output is made so that the LED output is disabled when not sampling (you can see a reference to that here and read about it under LED output in the QDEC chapter in the product specification).