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HB3x2 Dual 3 Amp H-Bridge for Robotics

The HB3x2 is a compact, dual H-Bridge designed with robotics in mind. It has 2 independent MOSFET motor drivers and is compatible with Arduino, AVR, Basic Stamp, Propeller, PIC, PICAXE, and many other microcontrollers. The HB3x2 requires only 2 wires per motor freeing more I/O on your microcontroller.

hb3x2 assembled

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We designed the HB3x2 to power a pair of motors for our local robot club's mini sumo robots. It turned out so good that we thought others in the robotics community might like one as well. The schematic and design are open source for everyone to use. We provide source code and wiring examples for AVR, Propeller, Basic Stamp, and Arduino.

The HB3x2 is currently distributed as a surface mount kit and is an excellent intro to surface mount soldering. If you've been thinking about learning how to surface mount solder then this is a great way to learn. If you don't want to surface mount solder the kit together we also offer an assembled and tested version.

What is An H-Bridge

An H-Bridge translates low level voltages from a microcontroller to high current signals that can cause a motor to spin. You must have an H-Bridge or other type of motor controller if you want to connect a motor to your microcontroller. Hbridges allow motors to turn both forward and backwards and at variable speeds. The HB3x2 is ideal for small combat robots such as mini sumo. It is also an excellent H-Bridge for other robotics tasks where a medium sized (up to 3 amp burst) motor needs to be controlled.

David Cook does a great job explaining H-Bridge circuits on his Robot Room website. It's definitely worth a read if you are new to the topic.

Assembly Guide

Check our our Assembly Guide here. It includes how to identify the components in the kit, correct order of assembly of the compoents on the board, and a variety of pictures to help you get your kit ready to work.

We also have a Testing and Troubleshooting Guide on bench testing the board including what waveforms to drive the board with.

Minimum and Maximum Ratings

The output drivers on the HB3x2 are IRF7343 HEXFETs from International Rectifier. You can read the data sheet for these devices here.

According to IRF the maximum continuous current rating for IRF7343 devices in this configuration when running at 10V is 2.7 Amps. The maximum pulsed current rating is 27 Amps and the maximum power dissiapation at 70 degreesC is 1.3 Watts. While the drain to source voltage is listed at 55 Volts you'll see that the gate drivers severely limit that range.

The gate drivers are LM5110 devices made by National Semiconductor and the data sheet is available here.

The minimum voltage for this chip is 3.5 Volts and the maximum voltage is 14 Volts. These numbers are the cutoffs for the HB3x2. To summarize:

Minimum Voltage 3.5 Volts
Maximum Voltage

14 Volts

Maximum Current, Sustained 2.7 Amps
Maximum Current, Burst 27 Amps
Maximum Power 1.3 Watts

Sample Source Code

We have written some very basic guides on how to get the HB3x2 working on a few microcontrollers. Each guide includes a schematic of how to wire up the H-Bridge and some source code to get it working.

What's In The Kit

Quantity Desc Manu Part Num DigiKey
2 100uF aluminum caps EEE-1CA101WP PCE3880CT-ND
2 LM5110 MOSFET driver LM5110-1M/NOPB LM5110-1M-ND
3 .1uF ceramic caps 08055C104KAT2A 478-1395-1-ND
1 4.7uF tantalum cap 293D475X9016A2TE3 718-1148-1-ND
4 10k resistor RC0805JR-0710KL 311-10KARCT-ND
1 terminal block 39357-0002 WM7877-ND
4 2.2k resistor CRCW08052K20JNEA 541-2.2KACT-ND
4 IRF7343 output FETS IRF7343TRPBF IRF7343PBFCT-ND
1 male header, 10 pin 68000-110HLF 609-3250-ND
1 PCB    

If you have any questions email me here: jason (at) efundies.com

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Jason Bauer

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Jason Bauer is an owner and programmer for Portforward.com. He's allergic to twitter and facebook, but you can find more of his articles in the Guides section.
Wednesday, 21-Mar-2018 11:17:59 PDT