Pololu Dual VNH5019 - Manual (Page 10)

Power Connections and Considerations
Dual VNH5019 motor driver shield power buses when connected
to an Arduino.
In the shield’s default state, the motor driver shield and Arduino are powered separately. When used this way, the
Arduino must be powered via USB, its power jack, or its VIN pin, and the shield must be supplied with 5.5 to 24 V
through the large VIN and GND pads on the right side of the board. Attempting to power the shield through other
means, such as from the Arduino or through the small VOUT pin, can permanently damage both the Arduino and the
shield (only the large power traces on the right side of the shield are designed to handle the high currents involved in
powering motors). A high-side reverse-voltage protection MOSFET prevents the shield from being damaged if shield
power is inadvertently connected backwards. Logic power, VDD, is automatically supplied by the Arduino.
Note that the motor driver features over-voltage protection that can activate at voltages as low as 24 V,
so we do not recommend using it with 24 V batteries (such batteries can significantly exceed 24 V
when fully charged).
It is important that you use a power source that is capable of delivering the current your motors will
require. For example, alkaline cells are typically poor choices for high-current applications, and you
should almost never use a 9V battery (the rectangular type with both terminals on the same side) as your
motor power supply.
Pololu Dual VNH5019 Motor Driver Shield User’s Guide © 2001–2014 Pololu Corporation
3. Getting Started with an Arduino Page 10 of 28