adc current

[VishalPrajapati]

I am using nRF52832. For reading ADC value for battery level  percentage i  have used 800k and 1M ressitor value. But while reading ADC Current cosumption is reached to 3 to 4 mA. How can i reduce this and what is ideal current consumption for reading ADC Values.

[Karl Ylvisaker]

Hello,

For reading ADC value for battery level  percentage i  have used 800k and 1M ressitor value.

Which pin are you using for this?
Please be advised that the SAADC has a routing to VDD directly, so you do not have to go about using an external connection.

An exempt from its documentation reads:

The analog inputs can be configured as eight single-ended inputs, four differential inputs or a combination of these. Each channel can be configured to select AIN0 to AIN7 pins, or the VDD pin. Channels can be sampled individually in one-shot or continuous sampling modes, or, using scan mode, multiple channels can be sampled in sequence. Channels can also be oversampled to improve noise performance.

But while reading ADC Current cosumption is reached to 3 to 4 mA.

Could you elaborate how you have measured and tested this? Is something else going on in your program simultaneously, such as BLE communication, or other peripherals being used?

Looking forward to resolving this issue together.

Best regards,
Karl

[VishalPrajapati]

Hello Karl 

I am using P0.03/AIN1 pin for ADC Measurement. I am measuring current through removing ferrite bead in series with power supply of IC. I am using mbn52832 module. All other activities are stopped.When i am reading ADC values i am getting this 3 to 4 mA of current.

[Karl Ylvisaker]

Hello,

VishalPrajapati said:

I am using P0.03/AIN1 pin for ADC Measurement.

 Is there a reason why you are not having the SAADC sample the VDD bus directly?

VishalPrajapati said:

I am measuring current through removing ferrite bead in series with power supply of IC.

I am not sure I understand what you mean by this - could you detail how the SAADC current consumption is measured?
How is your test setup? A connection- or other -diagram would be useful to see, to understand how you have set this up.

VishalPrajapati said:

All other activities are stopped.When i am reading ADC values i am getting this 3 to 4 mA of current.

How are you triggering the sampling, are you doing it trough PPI, or using the CPU?
Do I understand you correctly that you are seeing a single peak of 3 - 4 mA when a sample is taken by the SAADC, or do you mean that there is a continuous draw of 3 - 4 mA after initializing the SAADC? Please be as specific as possible.

Looking forward to resolving this issue together,

Best regards,
Karl

[Karl Ylvisaker]

It would also be helpful to know what code you are running, when testing this.
Could you share your project here?

Please see the electrical specifications for the SAADC with regards to nominal current consumption of the SAADC during idle and active state.