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AE-MDL-MegaBridge
Improving the most versatile H Bridge you will ever find

Download AE-MegaBridge data sheet
Download AE-MegaBridge Schematic
Download AE-MegaBridge BOM

AE-MDL-MegaBridge

Although the AE-MDL-MegaMotor is having a great run ever since we released it a couple of months ago, I felt there was a little bit of a disconnect when it came for the board to drive the single H Bridge configuration devices. After some experiments, I noticed funky behavior which I attributed to the lack of true parallelism the single H Bridge devices might require. That is, two SENSE resistors instead of one and similarly two set of traces per output, instead of one, etc.

It was clear that to do this right, I needed to start from scratch. And so I set to redo my “kind of mess” with the result being the AE-MDL-MegaBridge. Pretty much the same board as the MegaMotor, but optimized for the single H Bridge arena.

This is still quite the flexible machine, with up to four possible combinations being available from the guys at Texas Instruments. These are:

Device Part Number

Motor Load

Max Current

Description

DRV8828

Half Stepper

3A

Single H Bridge. Up to 3A. ENABLE /PHASE

DRV8829

Half Stepper

5A

Single H Bridge. Up to 5A. ENABLE /PHASE

DRV8840

DC

5A

Single H Bridge. Up to 5A. ENABLE /PHASE. With BRAKE

DRV8842

DC / STP

5A

Single H Bridge. Up to 5A. IN1/IN2. With BRAKE

The board has been designed to make it easy to use. But then again, how hard could it be to use an H Bridge? Want to drive your inductive load with current regulation? No problem! A potentiometer (or an external analog voltage) will allow you to set what you want this current to be. Want to control direction of current flow? PHASE to the rescue! Or, if you prefer, IN1 and IN2 interface.

Of course we could not forget the all mighty speed control which we can easily achieve by PWMing either the ENABLE or the PHASE.

If you want to use this board to drive half of your bipolar stepper motor with up to 32 degrees of microstepping, the Ix bits will allow you to superimpose a 32 degrees of resolution sine wave on top of your regulated current. This is some major microstepping! The algorithm is very simple as all you have to do is increment/decrement the 5 bit binary value from 0 to 31 and then to 0 continuously.

The board has a dual set of connectors which give you easy access to cascade boards or the extra row can be used for debugging.

An optional surface mount heat sink can be added to improve thermal impedance. If you want to reach those 5A, you better consider this as there is no way you will be able to hold up that kind of current for too long otherwise. At 5A, we are dealing here with 5A*5A*0.3Ohms which comes to a whopping  7.5W of power dissipation. That package will certainly use whatever help you can throw at it.

Pins are properly documented at the back, although a small silkscreen can be found at the front in case you don’t like flipping your board every time you want to make a connection. Hey, I placed it in there for a reason...

Optional pull up resistors allow to configure each control line as asserted in case you don’t want to drive them with your microcontroller.

Drive your DC motor, solenoid, wire heater, etc with this board. It really is very simple!

Bare Board:

AE-MegaBridge

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