OLIMEX© 2018
A20-OLinuXino-MICRO user's manual
2.3 Powering the board
There are four possible ways of powering A20-OLinuXino-MICRO – via external supply providing
7-24V DC
at the power jack, from 5V USB port via USB_OTG connector, from 3.7V Li-Po battery
via the LIPO_BAT connector, from 5V source applied to 5VEXT test pad at the bottom of the board
and any GND. Note that the board consumes around 300mA of current at 12V when there are no
peripherals connected to the USB hosts, so make sure the power supply is able to provide at least
500mA before plugging. Depending on your preferred way of powering you might need additional
hardware.
The preferred way of powering the board is via the PWR jack with 7-24V DC with a power of at
least 5W (usually 6Vx1A, 12Vx0.5A, etc.). This will make the board fully powered and able to
power all the peripherals connected to it.
Important: Not all USB ports would be able to provide enough power for the board. Try using
another USB port or a cable of higher quality. If you have to use USB for powering, consider
externally powered USB port. The best practice is not to count on the mini USB-OTG as a single
power source!
The absolute maximum current available for the board and peripherals when the power supply is
supplied via USB-OTG connector is 900mA (no matter how much current you have available,
AXP209 would output no more than 900mA). Of course, a big part of the current is required for the
board itself (without anything extra attached)! For comparison, when the power jack is used to
power the board – the typical current available after the AXP209 is 2500mA!
Note that when powering the board from the USB_OTG, the power provided might be insufficient
to also power a bigger LCD connected to the LCD_con. However, this power option is capable of
driving the board when using external display connected to the HDMI connector.
The typical consumption of A20-OLinuXino-MICRO is between 100mA and 320mA depending on
the current load and the power voltage applied.
If the board has entered power-down state you can bring it back without restart using the
PWR_BUT. The PWR_BUT is also used to start the board when powered from a Li-Po battery on
the battery connector.
Sometimes when starting Android it is possible the board to enter battery save mode even before
booting fully. Especially, if you have turned off the board without quick boot mode enabled. In this
case you should press the PWR_BUT for at least 5 seconds which would allow the board to start.
For the European customers we sell two power supply adapters, please check chapter 2.2. We also
sell USB OTG to USB type A cables if you lack such.
Note that it is normal that when the board is powered some integrated circuits might appear hotter
than others. This is perfectly normal for some chips – for instance – voltage regulators and the main
processor.
3
For boards revision J or newer; the voltage applied to the power jack should be (6-16)V for older board revisions
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