Overview

Pololu Reverse Voltage Protectors are tiny 0.3″×0.5″ modules that can be inserted between a power supply and its load to protect that load from damage in the case of accidental reversal of power polarity. They operate from 4 V (3.2 V after startup) to 60 V and provide protection from negative voltages down to -60 V. They are available in two different power levels (10 A or 12 A) and with or without reverse current blocking, providing four options in all:

Pololu Item #	Max current	On resistance	Reverse current blocking	Price
#5380	10 A	< 10 mΩ	no	$1.49
#5381	12 A	< 5 mΩ		$1.95
#5382	10 A	< 10 mΩ	yes (ideal diode)	$1.75
#5383	12 A	< 5 mΩ		$2.25

The versions without reverse current blocking are suitable for use with loads that have the potential to send current back into the power supply, such as motors. The versions with reverse current blocking act as ideal diodes, preventing any current from flowing from the load back into the supply.

Note: Any voltage on the output will reduce the 60 V maximum rating. For example, if there is a large capacitor charged to 24 V on the ouput, the minimum negative voltage would be -36 V.

Details for item #5380

Pololu Reverse Voltage Protector, 4-60V, 10A, top view.

Pololu Reverse Voltage Protector/Ideal Diode Reverse Voltage Protector, bottom view.

This module uses an LM74500-Q1 reverse voltage protection controller and N-channel MOSFET to provide protection from negative voltages down to -60 V. It operates from 4 V (3.2V after startup) to 60 V and has a VIN path impedance of approximately 10 mΩ when the MOSFET is on (i.e. when power is connected with the proper polarity), enabling currents up to around 10 A continuous (and up to around 30 A for a few seconds). This version does not block reverse current, making it suitable for applications such as motor control, which have the potential to deliver energy back into the supply.

Operating voltage	Max current	On resistance	Reverse current blocking
4*-60 V	10 A	< 10 mΩ	no
* Operates down to 3.2 V after startup.

Connections

Supply power and ground connect to the VIN and GND side of the board, and the VOUT and GND pins connect to the load. If the supply is connected correctly, with its positive voltage on VIN, the power will pass through the board to VOUT. If the supply is connected incorrectly, with the positive voltage on GND, supply power will not pass through to the output, and any connected load will be protected from the reversed supply voltage.

The input and output slots can accommodate a variety of connectors, including 5mm-pitch terminal blocks, 3.5mm-pitch terminal blocks, 0.2″-pitch headers, and 0.1″-pitch headers.

Examples of various connectors that can be used with the Pololu Reverse Voltage Protectors (from left to right: 5mm terminal blocks, 3.5mm terminal blocks, 0.1″ headers).

Pololu Reverse Voltage Protector soldered to a pair of two-pin, 5mm-pitch screw terminal blocks (not included).

Pololu Reverse Voltage Protector soldered with 0.1″ male headers (not included) for use in a breadboard.

Optional TVS diode mounting location

There are pads for adding an optional SMB-size transient voltage suppressor (TVS) across VIN and GND on the bottom side of the board:

We can manufacture these with the TVS diode of your choice for custom high-volume orders (typically at least a few hundred pieces). If you are interested in such a customization, please contact us for a quote.

Schematic