PPK2 measuring high PSM consumption

[Oette]

I was measuring the power consumption of a custom board and it seemed to consume around 100µA in PSM mode. At first I thought there was something wrong in the firmware, but after testing the UDP sample on nrf9160dk, the average PSM consumption is 230µA according to the PPK2.

I am using the UDP sample code of NCS v1.5.0, modem FW v1.2.3 and DK v0.9.1. network is configured to use NB-IOT.

part of prj.conf:

# LTE parameters
## Network Mode / LTE category
##CONFIG_LTE_NETWORK_MODE_LTE_M=y
CONFIG_LTE_NETWORK_MODE_NBIOT=y

## PSM
CONFIG_UDP_PSM_ENABLE=y
CONFIG_LTE_PSM_REQ_RPTAU="0010001"
CONFIG_LTE_PSM_REQ_RAT="00000000"

## eDRX
CONFIG_UDP_EDRX_ENABLE=n
CONFIG_LTE_EDRX_REQ_VALUE="1001"

## RAI
CONFIG_UDP_RAI_ENABLE=n
CONFIG_LTE_RAI_REQ_VALUE="4"

This is what the measurement looks like:

When zoomed in you can see the base consumption is between 80µA and 230µA with spikes every 30ms going up to 4mA:

The behavior is similar whether I use the UDP sample or custom firmware, DK or custom board, which points me toward the issue being within the PPK2/PPK software.

I tried unplugging the SIM-card while in PSM-mode and saw no change in power consumption at all, which should mean the SIM is properly powered off and not causing the high consumption.

I also tried using 5 different USB-cables and different laptop/USB connectors so I doubt there is an issue with the connection either.

When enabling logging in the config file I get the print "parameter update: TAU: 648000, Active time: 0, RRC mode: Idle" which suggests that the request was accepted by the carrier.

Do you have any idea what could be wrong with my setup? Is my PPK2 faulty?

Thanks in advance,

Atte

[JONATHAN LL]

Hi,

Are you powering the device from the PPK2 or from an external source?
https://infocenter.nordicsemi.com/topic/ug_ppk2/UG/ppk/setting_up.html?cp=9_7_5 

Regards,
Jonathan

[Oette]

Hey,

I am powering it from the PPK2, but I also tried powering it from an external source and using ampere mode, but it gave me similar results.

[JONATHAN LL]

The 30 sec spikes are normal, those are the refresh mode spikes. And 230 uA is high for for the UDP sample.

try to sett 

CONFIG_SERIAL=n

And measure again. 

Regards,
Jonathan

[Oette]

I forgot to mention that I already have set it like that. When it's enabled the consumption is over 1mA.

[JONATHAN LL]

Is it 1mA in the UDP sample when CONFIG_SERIAL=n? For both DK and custom HW?

[Oette]

I meant it is over 1mA when the logging is enabled so CONFIG_SERIAL=y, on both boards.

In my screenshots I had CONFIG_SERIAL=n

EDIT: Here's the full prj.conf file:

#
# Copyright (c) 2020 Nordic Semiconductor ASA
#
# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
#

# General config
CONFIG_NEWLIB_LIBC=y
CONFIG_NEWLIB_LIBC_FLOAT_PRINTF=y
CONFIG_NCS_SAMPLES_DEFAULTS=y
CONFIG_SERIAL=n

# Network
CONFIG_NETWORKING=y
CONFIG_NET_NATIVE=n
CONFIG_NET_SOCKETS=y
CONFIG_NET_SOCKETS_OFFLOAD=y

# LTE link control
CONFIG_LTE_LINK_CONTROL=y
CONFIG_LTE_AUTO_INIT_AND_CONNECT=n

# Modem library
CONFIG_NRF_MODEM_LIB=y

# Heap and stacks
CONFIG_HEAP_MEM_POOL_SIZE=1024
CONFIG_MAIN_STACK_SIZE=4096
CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048

# LTE parameters
## Network Mode / LTE category
##CONFIG_LTE_NETWORK_MODE_LTE_M=y
CONFIG_LTE_NETWORK_MODE_NBIOT=y

## PSM
CONFIG_UDP_PSM_ENABLE=y
CONFIG_LTE_PSM_REQ_RPTAU="00100110"
CONFIG_LTE_PSM_REQ_RAT="00000000"

## eDRX
CONFIG_UDP_EDRX_ENABLE=n
CONFIG_LTE_EDRX_REQ_VALUE="1001"

## RAI
CONFIG_UDP_RAI_ENABLE=n
CONFIG_LTE_RAI_REQ_VALUE="4"

[JONATHAN LL]

I dont see anything that should cause the increased current consumption here. Are you able to measure current with a different device to se if the PPK2 is at fault.

At least your HW seems to preform equally to the DK so that does not seem to be the issue. 

Could you send me the hex file that you use on the DK so that i can try to replicate the results?

Regards,
Jonathan

[Oette]

I tested ppk with a 200kohm resistor and 1500mV supply voltage and the measurement was 7,67µA. In theory it should be 200kohm/1,5V=7,5µA, so the PPK2 seems to be working correctly.

Here's my hex file (note that it uses nbiot):

udp_sample_nbiot.zip

[nta_xyz]

I have exactly the same issue! did you manage to find the problem? 

[Oette]

Not yet, I'll let you know if I figure it out

[Oette]

Hey JONATHAN LL nta_xyz,

The problem was a faulty DK, with a new DK the consumption is where it should be.