Arduino Pro Mini [Atmega328p] - VCC is consuming more power than RAW

Hi,

I've got problem with my Arduino Pro Mini.

When I supply power through RAW pin the power consumption is about 10mA and 1.6-1.7mA in the sleep mode which is quite OK (obviously I'm using sleep functions and low power library to achieve that).
but when I connect the same power source to the VCC pin (nothing connected to RAW and therefore bypassing voltage regulator) the power consumption is about 30mA!
Is it possible that some kind of back current is going through voltage regulator or something?

Any ideas are welcome :slight_smile:

PS: I've seen on youtube that someone has exactly the same issue as me: - YouTube

It's certainly possible...

PS: If you remove the regulator and power LED you should be able to get a sleep mode consumption of about 5uA.

That sounds odd.
This remote uses 8 MHz 3.3V Promini powered with LiPo connected to VCC
When transmitting, power is ~15mA, drops down to ~5mA when in power down sleep mode in between button presses; LED uses some, Tx uses some, MAX1811 for battery charge control uses a little, maybe some leakage to the regulator. 1000mAH battery goes at least a month between charges and in frequent use.
You could try adding a diode from Vcc (anode) to RAW (cathode) to avoid reverse driving the regulator.

Thanks guys for the answers.

fungus:
It's certainly possible...

PS: If you remove the regulator and power LED you should be able to get a sleep mode consumption of about 5uA.

yeah... unfortunately I think it too :frowning:
yesterday I searched for the datasheet of that regulator and definitely in the application note they recommend to never leave input floating... which on the other hand is weird because MiniPro allows you to use VCC pin only...
However removing the regulator and power LED was my plan too :slight_smile:

CrossRoads:
That sounds odd.
This remote uses 8 MHz 3.3V Promini powered with LiPo connected to VCC
When transmitting, power is ~15mA, drops down to ~5mA when in power down sleep mode in between button presses; LED uses some, Tx uses some, MAX1811 for battery charge control uses a little, maybe some leakage to the regulator. 1000mAH battery goes at least a month between charges and in frequent use.
You could try adding a diode from Vcc (anode) to RAW (cathode) to avoid reverse driving the regulator.

I know it's odd!
To be honest - yesterday I assembled another MiniPro (another clone) - this time the Mini is 5V 16MHz and uploaded exactly the same software (using exactly the same computer and Arduino IDE) and ...... The results are as you could expect!
I managed to reduce power usage to 0.2mA! (200uA) in the sleep mode - which is great! and I didn't remove power LED!

I think it could be that the other MiniPro is kind of "broken" - it works but I bought it as 5V 16MHz and it appears to be 3.3V 16MHz which is odd again :stuck_out_tongue: (some midnight run?)
Obviously I re-burn the bootloader to use 8MHz internal oscillator and then even change the BOD fuse but that didn't help - MiniPro still draws 1.6mA in the sleep mode through RAW and ~30mA through VCC...

to sum up - I think this regulator is to blame.