USB inrush (bulk capacitance)
▲ warningcurrent/usb-inrush
What it looks like
VBUS hangs ~33 µF of hard-attached bulk capacitance off a USB port — the spec allows about 10 µF before plug-in inrush can brown-out the port.
What it checks
Adds up the bulk capacitance hard-attached to a USB-fed rail (no soft-start or current limiter between the port and the caps) and compares it with the USB specification's 10 µF inrush limit.
Why it matters
At plug-in, discharged capacitors look like a short. Past ~10 µF the inrush spike can droop the host port, corrupt enumeration, or trip polyfuses — a design that 'mostly works' depending on which laptop you plug it into.
How to fix it
Add a soft-start (load switch with controlled rise, or a simple P-FET RC slew), put the bulk capacitance behind a regulator, or reduce it to spec.
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