1power supplies – Digilent 410-274P-KIT User Manual
Page 3
Nexys4™ FPGA Board Reference Manual
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A growing collection of board support IP, reference designs, and add-on boards are available on the
Digilent website. See the Nexys4 page at
for more information.
1
Power Supplies
The Nexys4 board can receive power from the Digilent USB-JTAG port (J6) or from an external power supply.
Jumper JP3 (near the power jack) determines which source is used.
All Nexys4 power supplies can be turned on and off by a single logic-level power switch (SW16). A power-good LED
(LD22), driven by the “power good” output of the ADP2118 supply, indicates that the supplies are turned on and
operating normally. An overview of the Nexys4 power circuit is shown in Fig 2
.
Power
Jack
(J13)
3.3V
IC17: ADP2118
Power
Switch
(SW16)
Power On
LED (LD22)
Micro-USB
Port (J6)
VU5V0
J12
IC23: ADP2138
EN
800 mA
VIN
IC22: ADP2118
EN
PGOOD
3A
VIN
1.8V
1.0V
Power Source Select
JP3
J12
USB
WALL
BATTERY
EN
PGOOD
3A
VIN
JP3
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 to the power jack (JP3) and setting jumper J13 to “wall”.
The supply must use a coax, center-positive 2.1mm internal-diameter plug, and 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 Digikey or other
catalog vendors.
An external battery pack can be used by connecting the battery’s positive terminal to the center pin of JP3 and the
negative terminal to the pin labeled J12 directly below JP3. Since the main regulator on the Nexys4 cannot
accommodate input voltages over 5.5VDC, an external battery pack must be limited to 5.5VDC. The minimum
voltage of the battery pack depends on the application -if the USB Host function (J5) is used, at least 4.6V needs to
be provided. In other cases the minimum voltage is 3.6V.
Figure 2. Nexys4 Power Circuit