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Modifications
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Ligne 28 :
Ligne 28 : − + + + + + + − '''When USB unplugged''' : xxxx + − + + + + + + + + +
→Power Section
'''When USB plugged on MCU board''' : xxx
'''When USB plugged on MCU board''' : The "MCU board" is powered and generates its 3.3V. VBus is also at 5V and feed the '''Lipo Charger''' that charges the Lipo. On the other hand the Lipo being connected, its current voltages (say 4.2V at full charge) feed the '''Lipo 3V3 Reg''' and the '''Vsys''' on the MCU board. As a result, the "Cansat Base" is also powered with 3.3V (including the radio module).
Remarks:
# The CHG ''charging'' LED lits while the Lipo is charging.
# The "MCU Board" will be feed either by USB, either by Vsys. The higher voltage path will be used.
# If your Cansat consume as much power as the USB provides to the Lipo then your Lipo will not really charge.
# Close the '''Pwr Enable''' pads will shut down the regulators. So all USB Power is used to charge the Lipo.
'''When USB unplugged''' : the Lipo is not charging. The Lipo will discharge into the '''Lipo 3V3 Reg''' and MCU board '''Vsys'''. The MCU board and Cansat Base are powered.
'''When Lipo unconnected''' : xxx
Remarks:
* Close the '''Pwr Enable''' pads will shut down the regulators. This will spare the Lipo Power.
'''When Lipo is unconnected''' : no power can be charged into the Lipo and Lipo cannot get discharged into the voltage regulators. When plugged onto USB the power flow from Vbus to '''Lipo 3V3 Reg''' (bypassing the '''Lipo charger''' circuitry). So, the Cansat project can be powered from USB for testing purpose.
Remarks:
* The CHG '''charging''' LED will continuously blink when Lipo battery is not connected.
* Powering from USB is possible as long as the project is not too power demanding. USB power is limited to 500mA.