Digilent 410-183P-KIT - Manual (Page 3)

Basys3™ FPGA Board Reference Manual
VU5V0
1.8V
1.0V
3.3V
VIN1
VIN2
EN1
EN2
PGOOD1
PGOOD2
1A
2A
IC10: LTC3633
IC11: LTC3621
EN
PGOOD
300 mA
VIN
+ -
ON/OFF
Type A USB Host
Connector (J2)
JP2
J6
5V External
Supply
Micro-USB
Port (J4)
Power Source Select
JP2
USB EXTERNAL
Power On
LED (LD20)
Power
Switch
(SW16)
Figure 2. Basys3 power circuit.
The USB port can deliver enough power for the vast majority of designs. A few demanding applications, including
any that drive multiple peripheral boards, might require more power than the USB port can provide. Also, some
applications may need to run without being connected to a PC’s USB port. In these instances an external power
supply or battery pack can be used.
An external power supply can be used by plugging into the external power header (J6) and setting jumper JP2 to
“EXT”. The supply must deliver 4.5VDC to 5.5VDC and at least 1A of current (i.e., at least 5W of power). Many
suitable supplies can be purchased through Digi-Key or other catalog vendors.
An external battery pack can be used by connecting the battery’s positive terminal to the “EXT” pin of J6 and the
negative terminal to the “GND” pin of J6. The power provided to USB devices that are connected to Host connector
J2 is not regulated. Therefore, it is necessary to limit the maximum voltage of an external battery pack to 5.5V DC.
The minimum voltage of the battery pack depends on the application; if the USB Host function (J2) is used, at least
4.6V needs to be provided. In other cases, the minimum voltage is 3.6V.
Voltage regulator circuits from Linear Technology create the required 3.3V, 1.8V, and 1.0V supplies from the main
power input. Table 2 provides additional information (typical currents depend strongly on FPGA configuration and
the values provided are typical of medium size/speed designs).
Table 2. Basys3 power supplies.
Supply Circuits Device Current (max/typical)
3.3V
FPGA I/O, USB ports, Clocks,
Flash, PMODs
IC10: LTC3633 2A/0.1 to 1.5A
1.0V FPGA Core IC10: LTC3633 2A/ 0.2 to 1.3A
1.8V FPGA Auxiliary and Ram IC11: LTC3621 300mA/ 0.05 to 0.15A
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