High Power consumption mostly in sleep mode using nRF52832 ?

[vishal]

Hi,

We have developed one application using nRF52832 SoC and Sdk v15.0. For our application we have use ble_app_uart example as a peripheral and multi-link central example.

ble_app_uart peripheral is used as a sensor node with SAADC example merged and which is on battery powered device. Our application is sensor node wake up every 1 Hr and send sensor data to central device then it will go in sleep mode. When i measured current it is very high as per the following with DCDC enabled:

• When sensor node(ble_app_uart) advertising = 3.50mA
• When connected to central and sending analog value = 3.1 to 5mA peak.
• After done sending sensor node goes into deep sleep mode = 0.5mA.

Questions:

1. Why 0.5mA is consume is system OFF mode how can reduce this consumption upto 50uA.
2. 2 sleep mode: system on mode and system OFF mode which one is best and very low power consumption and also able to trigger by RTC.
3. If we use system OFF mode in sensor node for low power consumption is any way to wakup by external low power RTC, if yes How?
4. How i can go my sensor node into system ON mode after done sending data to central.
5. Please suggest if any changes in sensor node program for ultra low power solution? we are using SAADC, UART, BLE.
6. We need at least 1.5- 2 year battery life for sensor node only using coin any cell (1000mAh). How i can achieve this?

Thanks in advanced...!!!

[vishal]

Thanks for your reply..

I have call this function sd_ble_gap_adv_stop(m_conn_handle); after completed three channel but BLE advertising is not stop. I have also check disconnect event and not started again advertising. 

Will you please provide me small program snippet for how i can do this.

[vishal]

Hi Stian,

I have use app timer for wake up our sensor devices for every one hour. As you mentioned in your above reply i have call this all turn off peripherals in callback BLE transmission once done. But still my sensor device is connected to central it is not disconnecting connection.

We have problem with app timer for trigger adc every one hour. Once this time out event occur is it need to initialize again all turn off peripheral in other function. Or it goes into main loop. Because my adc is not start after app timer time out event occur.

Would you please suggest me where should i am going to wrong with your program snippet. 

We are waiting for your reply......

Thanks. 

[Nguyen Hoan Hoang]

First thing to check.  Do a main loop with __WFE(), nothing else.  Then measure the current to detect any hardware leak.

void main() 

{

   while(1) {

      __WFE();

   }

}

if this draw more than a few uA that means you have leaks somewhere on your board.  Reduce that leak first, then optimize your code for other stuff.  Just enable the UART alone will consume about 300uA.  

[Stian Røed Hafskjold]

Maybe you can open up a new thread in this forum where you explain in detail the workflow of your application. I'm not sure how you want the application to work, so it's hard to give you any code examples which explains things.

[Swathykc55]

I struggled with same. Got the solution ? Plz help me