US Robotics USR3520 User Manual page 100

Dedicated high current power circuit

Provides two different voltage rails which both can deliver high current levels:
o V_PWR: Is the voltage level of the power adapter limited to 1.2A. A little voltage drop lower
than 1V will be caused by the protection circuit.
o 3V4: A 3.4V power rail made by a dedicated power circuit which is used on the main board but
also accessible by the expansion boards
Low power circuit generated by the micro controller

Provides three voltage rails for very limited power:
o 3V3: A 3.3V power rail provided by the micro controller is used on the mainboard but also
accessible to the expansion boards
o 1V8: A 1.8V power rail provided by the micro controller and only used on the main board
o 1V2: A 1.2V power rail provided by the micro controller and only used on the main board
Voltage Rail Voltage
V_PWR Equals the
applied voltage
of the power
adapter
3V4 3.4V
3V3 3.3V
1V8 1.8V
1V2 1.2V
Revision: 1.00
Usage
Use for power-hungry
devices
Powers all standard digital
components on the
expansion cards
Powers low power
components or level
translators from I/O signals
on expansion connectors
towards other components
used the expansion cards
Internal use only
Internal use only
Copyright 2015 U.S. Robotics Corporation
Max Current
Current is limited to 1.2A
3A maximum of which the
main board is already using
1.5A. Only 1.5A is left for
both expansion cards. (The
sum of both expansion
cards should be lower than
1.5A)
Powers low power
components or level
translators from I/O signals
on expansion connectors
towards other components
used the expansion cards
Internal use only
Internal use only
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