MangOH Yellow power optimization

mangOH Yellow
1

Hello everyone,

I am currently working on a MangOH Yellow connected to Octave using the Orange LTE network in France. I am trying to lower the power consumption as much as possible
I measured the current consumption of the board for several use cases. The lowest configurations I found are the 2 presented below.

Configuration 1

For this configuration, I did the following:

  • Disable all Edge Actions
  • Disable all sensors (Location, IMU, Battery state, Light)
  • Disable Developer Mode
  • Disable “Heartbeat on empty”
  • Disconnect the 2 USB ports of the MangOH
  • Use LTE with the following command on the mangOH:
$ cm radio rat LTE

The results look like this:

floor_lte_graph
floor_lte_graph1611×1000 48.9 KB

Average current consumption is 147 mA with ~240 mA spikes.

If I zoom on this graph, I can see the consumption profile more clearly:

floor_lte_graph_zoom
floor_lte_graph_zoom2248×1361 939 KB

A 240 mA spike appears every 1.28 seconds (which corresponds to a normal paging cycle for LTE without PSM, according to this website).
As you can see, the device alternates between an activity period (~200 mA) and the floor level (125 mA) with a periodicity of ~2 seconds.
I suspect this is caused by the action manager of the mangOH, but I am not sure about that.

Configuration 2

For this configuration, I did the following:

  • Disable all Edge Actions
  • Disable all sensors (Location, IMU, Battery state, Light)
  • Disable Developer Mode
  • Disable “Heartbeat on empty”
  • Disconnect the 2 USB ports of the MangOH
  • Disable LTE and GSM connection using this command on the board:
$ cm radio off

The results look like this:

floor_graph
floor_graph2248×678 527 KB

Average current consumption is 130 mA with ~160 mA spikes.
I don’t know what the 2 big spikes of 220 mA (appearing at 1 min and at the very end) corresponds to, as the board was not supposed to send anything to Octave. If anyone has a clue about this, I’m interested.

Again, if I zoom on the profile I get this:

floor_graph_zoom
floor_graph_zoom2248×1361 964 KB

The floor level went down to 118 mA, and as we could expect the periodic spikes are gone as radio communication is disabled.
The device still alternates between an activity period (~140 mA) and the floor level (125 mA) with a periodicity of ~2 seconds.

However, the power consumption is still very high, that is why I am asking the following questions:

  • Q1 : Is there a way to get the power consumption any lower using Octave / other ?
  • Q2 : What is your target power on mangOH Yellow + Octave ?

I Hope someone can help me with this.

Have a good day ! :slight_smile:

1 Like
2

Hi Paul,

One big way to reduce power is to put the HSIC interface into suspend mode. This can drop power by 60 ma.
–> echo 0 > /sys/bus/usb/devices/usb1/authorized
Also make sure wakelock is set in case USB cable is removed:
–> echo NO_SLEEP > /sys/power/wake_lock
Also, if you are ready to take a soldering iron, you can get some more improvements:
a. Add R306 (0R), and check that EXT_GPS_LNA_EN signal is set 0. Should be 4ma saving
b. Savings over LEDs:
–> echo ‘AT!LEDTEST=0,1;!LEDTEST=0,0’ > /dev/ttyAT (Red LED off, 1.5ma)
–> Remove R428, save couple of ma
c. Remove USB cable (have a wakelock running though): 12-15ma
d. If you want to, you can force the DC/DC buck converter into automatic PFM/PWM mode . Save around 10 ma. Remove R901,remove c901. Add 10K between r901.pin_mode to c901.gnd. image
e. Run CPU in interactive mode:
—> echo interactive > /sys/bus/cpu/devices/cpu0/cpufreq/scaling_governor

If you want to know how low the board can go, you can remove R908 and add R909.
Then pull-up pin 3 of SW401. This will allow you to power off everything on the board except the module and the ULPM circuitry. If you bring down pin 3 of SW401, you will get all circuitry powered back up. We see module consuming 1.0ma and sensor circuitry at 1.3ma.

Further, you can put the board in ULPM mode:
AT!POWERWAKE=CLEAR

AT!POWERWAKE=1,60

AT!POWERMODE=1 (VGPIO gets low)

I will publish this on the mangoh website over the next few days . Let me know what numbers you hit.
Would be great if you can post your numbers here.

regards,
Ashish

5 Likes
3

Thank you very much @asyal for this helpful answer ! :smiley:
I will try this as soon as I can and I’ll keep you updated with the results !

4

Thanks for solving this solution, very impressive codes.