8x931HA USB Customer Hub
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Advance Information Datasheet
3.6.2
Input Power Specification
CHUB is designed to run from self or bus-powered modes. Self-powered mode allows the user to
plug in a 5 Volt power supply to provide HUB power. Bus-powered mode allows the user to draw
power from the USB cable.
In Self powered mode, Intel has specified the power supply be 5.0 V +/- 2%. Typically, 5V power
supplies do not specify to this tight tolerance. Typical power supplies are +/- 5%. The CHUB will
operate and run with a 5V +/-5% power supply, but will not have the allocated voltage drop budget
allowed. Any power supply used should have the ability to provide a minimum of 2 Amps
continuous current.
The USB system designer is responsible for ensuring that the allocated Vdrop budget meets the
USB specification.
3.6.3
Overcurrent Tripping
The CHUB has been designed to provide a .560 ms delay upon overcurrent detection. This solution
has helped to solve the problem of detection of false overcurrent detections (due to hot-plugging)
by delaying the input response to OVRI# by .560 ms.
Intel recommends that the USB system designer pay close attention to the method of detecting
overcurrent protection for USB systems.
