Clarification on low_power example and current consumption

[superslot]

Hi,
I’ve seen few posts on the current consumption in deep_sleep mode but I’m still confused … so asking one clarification.

I’m using an AB01 with the default low_power_with_timer example and I’m measuring current over the USB 5v plug (nothing is connected, no battery, no solar).

I’m seeing 8mA in deep_sleep, 19mA in wakeup.

===
this is far away from the published values, how do we measure the uA current documented values?

1. are these values valid only when powering from the lipo battery or external 3.3v ?
2. could you post a configuration setup for the measure 3.5uA deep sleep current mode?

thanks

[superslot]

actually I’ve got almost a full reply to my question reading the link in a previous post here:

Heltec CubeCell

but if someone could confirm that the low_power current is NOT doable when running from USB plug it would be great

[ksckung]

When you power the unit via USB, most likely the USB to UART IC will enable and draw ~8mA current.

1.When you power via Vbat or 3.3V, the USB to UART IC will disable, the current should be equal to documented values.

2. Using a 3.3V power supply. Power the unit via VDD and GND.

[ksckung]

I think you can check this to reduce the current of “Deep sleep with battery connect”.

Power consumption in Sleep mode (Vbat /battery powered)

On my HTCC-AB01, the BR0 is connected to AO7801 S1, not D1. It creates a sink current to the ADC pin and pullup the Vdd from 3.3V to 3.4V. After I remove BR1 and use a jumper wire connect ADC to D1 , the Sleep mode Current (Vbat /battery powered) at 4.2V will be normal and 3.3V power does not goes higher. Also, I found out HTCC-AB01 using 2 10k resistors as a voltage divider, but HTCC-AB02 using 2 100k resistors as a voltage divider. I replace 10k with 100k without any issue and reduce curre…

[superslot]

thanks for your suggestion KSckung.

unfortunately I do not have the tools to replace the resistors on the AB01 … I can manually reach 0805 size … and pbly 0603 … but below this size I cannot do reworks.

It would be great if Heltec sends out an updated version of the AB01 with the fixes to reach very low power in deep sleep mode. And also as I mentioned in another post it would be GREAT if you can expose the pad for the “enable” pin on the voltage regulator. This way we can add an external “backup battery” (like an alkaline battery) when the onboard lipo is empty.

CubeCell UPS:adding secondary backup battery

[%E5%9B%BE%E7%89%87]

[ksckung]

The main point is to correct the ADC pin connection.

1. remove BR1 0R resistor.
2. connect ADC pin to D1 or R17( not GND) pad.
   
   
   
   
   

[superslot]

ok.

one last question: which one in your picture is the 0-ohm resistor that needs to be removed?

thanks

[ksckung]