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low power consumption pbyL board

Posted: Thu Aug 29, 2019 4:37 am
by shaoziyang
I have made new ultra low power consumption pybL board.
pybl.jpg
pybl.jpg (131.57 KiB) Viewed 479 times

feature
  • STM32L476RG microcontroller
  • USB type-c
  • Ultra Low Power Consumption with current test interface
  • optional SPI flash
pybL-pins.png
pybL-pins.png (145.55 KiB) Viewed 479 times

Re: low power consumption pbyL board

Posted: Thu Aug 29, 2019 4:44 am
by shaoziyang
running power consumption
pybL-1.jpg
pybL-1.jpg (185.21 KiB) Viewed 453 times
(series 10 Ohm resistor)

deepsleep power consumption
pybL-2.jpg
pybL-2.jpg (212.79 KiB) Viewed 478 times
pybL-4.jpg
pybL-4.jpg (186.74 KiB) Viewed 478 times

Re: low power consumption pbyL board

Posted: Thu Aug 29, 2019 7:28 am
by pythoncoder
Deep sleep current is amzing, but the "running power consumption" picture doesn't seem to tell us much. What sort of figure is achievable running MicroPython?

Re: low power consumption pbyL board

Posted: Thu Aug 29, 2019 3:19 pm
by shaoziyang
I am sorry to put the wrong picture, I have fixed it.

In running mode, it about 10mA.

Re: low power consumption pbyL board

Posted: Thu Aug 29, 2019 3:49 pm
by Roberthh
Do youi also use the 10 Ohm shunt resistor in the current test for sleep mode?

Re: low power consumption pbyL board

Posted: Fri Aug 30, 2019 1:10 am
by shaoziyang
Yes, it will make the display data a little smaller.

Re: low power consumption pbyL board

Posted: Fri Aug 30, 2019 6:49 am
by Roberthh
If I understand the properties of your multimeter right, the internal shunt for the µA range is 1000 Ohm (199.99mV/199.99µA). With the external shunt of 10 Ohm this means, that only about 1% of the current goes through the multimeter. So instead of the shown ~10nA, the devices consumes about 1 µA. That matches the data sheet of the STM32L476RG microcontroller, and is still an excellent value ( ~23 years standby on a 200mAh battery, if only the battery would last that long).

Re: low power consumption pbyL board

Posted: Fri Aug 30, 2019 1:55 pm
by shaoziyang
I use ZT303, a 4 1/2 bits multimeter. Internal shunt for uA is about 100 ohm, not 1000 ohm.

Re: low power consumption pbyL board

Posted: Fri Aug 30, 2019 2:03 pm
by Roberthh
Then the current has to be corrected by a factor of 11. When the meter shows 90 nA, the actual current is ~1 µA. (In my previous post I read the meter wrong as ~10nA).

Re: low power consumption pbyL board

Posted: Sat Aug 31, 2019 10:19 am
by shaoziyang
Current firmware is not reach the minimum power consumption of STM32L476, but its power consumption is low enough for most battery-powered applications.