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Blevene / LabsConBadge_2023

LabsConBadge 2023
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Add power switch and allow usb power #3

Closed securelyfitz closed 1 year ago

securelyfitz commented 1 year ago

Right now, VUSB is connected to VBATT via ferrite bead FB1. This would means VBATT (AAA, cr2032) and VUSB are both connected to the boost regulator VIN and either can power the badge. If both VUSB (5v) and VBATT (3.2 or 1.5) are connected at the same time, there's a bad short.

Currently, FB1 is DNP to isolate the supplies. The result is that the board needs a battery to work, even if usb is attached. Biggest downside is that it uses battery power when connected, and there's no real on/off method without removing battery

Solution - add a power switch that connects VBATT or VBUS to VIN. When on battery power, it acts as a power switch When plugged in to usb, it's always powered. This means you have to switch the switch to power cycle.

Switch label should say ON(BATT)/OFF(USB) or similar

securelyfitz commented 1 year ago

dillemma: the XT1861 boost regulator lets higher voltages pass through. Need to step 5v down before boosting. There's probably a more graceful solution, but given time constraints, adding a 1117 or similar is probably the quickest answer

securelyfitz commented 1 year ago

rolled up into #12