Power Supplies - Digilent Basys MX3 Reference Manual

Basys MX3™ Board Reference Manual
#pragma config POSCMOD =
#pragma config OSCIOFNC =
#pragma config FPBDIV =
#pragma config FPLLIDIV =
#pragma config FPLLMUL =
#pragma config FPLLODIV =
2

Power Supplies

The Basys MX3 requires a 5V power source to operate. This power source can come from the Programming /
Debugging USB port (J12), the USB-UART (J10), or from an external 5V DC power supply that's connected to Power
Jack (J11). These three power inputs are connected through Schottky diodes to form the primary input power
network, VIN, which is used to power the onboard regulators and the majority of the onboard peripherals. No
jumper is required to select the input power source. The board will automatically power on while the Power Switch
(SW8) is in the on position and power is present on any of the power inputs.
A power-good LED (LD11), driven by the output of the 3.3V regulator (LMR10515), indicates that the board is
receiving power and that the onboard supplies are functioning as expected. An overview of the Basys MX3 power
circuit is shown in Fig 2.1.
VEXT (0 – 11V)
Terminal
Block
(J5)
5V Input
Power
VBAR
Jack
(J11)
Micro-USB
DBG_5V0
Port (J12)
DEBUG
Micro-USB
FT_5V0
Port (J10)
UART
The USB port(s) can deliver enough power for most designs; however, a few demanding applications, including any
that drive multiple peripheral boards, may require more power than a USB port can provide. In these instances, an
external power supply can be used. Due to their high current demands, motors and servos cannot be powered
through either of the USB ports, and may only be powered through an external supply.
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XT
ON
DIV_1
DIV_2
MUL_20
DIV_1
JP1
VM
Motor
1
Driver
IC7: DRV8835
1
J1
Servo Headers
1
J2
VIN -
+
ON/OFF
PWR_ON
Power
Switch
(SW8)
Figure 2.1. Power supply circuit.
VU5V0
VIN 1.5A
EN
IC10: LMR10515
VIN
VIN VOUT
ON
IC11: LP2985IM5-3.3
VCC3V3
Power On
LED (LD11)
DBG3V3
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