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  • Author Author: fvan
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Infineon DC Motor Control Shield - Observations, Modifications & Tests

fvan

 

Introduction

 

Element14 was kind enough to provide me with an Infineon DC Motor Control ShieldInfineon DC Motor Control Shield after the Internet of Holiday Lights RoadTest Plus, in which contestants were given another Infineon shield as part of the kit: the Infineon RGB LED ShieldInfineon RGB LED Shield.

 

This post will cover my first observations and tests using the DC Motor Shield. You can find my review and project using the RGB LED Shield here.

 

 

 

 

DC Motor Shield

 

The shield is built around two BTN8982TA: a high current half bridge for motor control applications.


The BTN8982TA package consists of:

  • a driver circuit
  • one p-channel highside MOSFET
  • one n-channel lowside MOSFET

 

Offering:

  • logic level inputs (driver circuit)
  • high PWM frequency control capabilities
  • various protections, such as: undervoltage, short circuit, overcurrent and overtemperature
  • diagnosis with current sense
  • adjustable slew rates (fixed on the shield though)

 

 

source: BTN8982TA datasheet                                             

 

 

First observations

 

Out of the package, the board looks very well made and of high quality. There are however a few things that immediately drew my attention:

  • no headers on the board or in the box
  • a huge vertically mounted capacitor
  • no (screw) terminals, but instead big ring shaped pads

Top and bottom view of the shield

 

 

No headers

 

This was already the case with the RGB LED Shield. My main problem with this is that you cannot start using the shield right away. If you have anticipated for the missing headers, the only remaining task is to solder them on. Else, you're stuck with an unusable shield until you are able to find a fitting pair of headers, which would probably delay you a day or two.

 

The fact that no headers are soldered on does give you the option to choose your own header type though: stackable, long, short, ... Whatever type suits your needs.

 

My suggestion remains the same as last time: include a pair of tall stackable headers in the box, preferably even soldered on.

 

 

Huge capacitor

 

The huge capacitor in the middle of the board really sticks out: about 25mm! One of the advantages of the BTN8982TA, is that it has very low board space consumption for the features it offers. I personally feel the capacitor obsoletes that advantage completely. It also prevents other shields to be stacked on top of this one, which seems like a big problem as other shields with displays or prototyping areas require to be on top.

 

Couldn't the capacitor have been put on its side ?

 

 

No (screw) terminals

 

One of the things I liked very much about the RGB LED Shield, were the screw-less terminals for both the power supply and the RGB LED strip. I was expecting something similar for this shield, but instead found big ring shaped pads. This will require soldering as opposed to the terminals, which makes it less practical for testing different types of motors and power supplies.

 

Is there a specific reason (except cost), why pads would be better than (screw) terminals ?

 

 

Software

 

I was looking for some sample code to use the shield with an Arduino, but I couldn't find any!

 

Not on the Infineon or E14's pages on the shield:

 

Unfortunate, but not a disaster as the shield seems easy enough to control.

 

This is the test sketch I came up with for testing:

 

 

First tests

 

There are two tests I wanted to perform using the motors I had at hand:

  • half-bridge configuration: controlling two unidirectional DC motors
  • H-bridge configuration: controlling a single bidirectional DC motor

 

But first ... finding a set of suitable headers to be able to use the shield and make some practical modifications.

 

Headers

 

I've ordered tall stackable headers for Arduino, but it will take some days until they get here. In the mean time, I've been experimenting with what I had at hand.

 

The first tests was to use different size male headers with an Arduin UNO. Using the typical size male headers, there was contact between the shield's VBAT connector and the UNO's USB port, which would create a very nasty short circuit. With a different size male headers the problem was resolved for the UNO.

 

Testing different size headers to avoid contact between shield and USB port on the UNO

 

The next test was about finding suitable headers for the YUN. The Arduino YUN has a vertically mounted USB port and an ethernet port, which are sure to cause problems as they are taller than the UNO's USB port. The tall headers working for the UNO were too short for the YUN and had to be combined with intermediate female headers.

 

Finding an appropriate combination of headers for the YUN

 

I'll be posting an update as soon as I receive the tall stackable headers I've ordered. In the mean, this will have to do

 

UPDATE: Extra tall stacking headers have arrived! The clearance for the YUN is just enough, I did put some tape on the bottom of the shield to avoid direct contact. With the capacitor on its side, it is possible to plug in another shield on top of the motor shield, although it should have long headers.

 

Motor shield with extra tall stacking headers

 

Modifications

 

There are two modifications I made, based on the feedback given during my first observations: laying the capacitor on its side and using screw terminals.

 

Screw terminals and capacitor on its side

 

Single bidirectional motor

 

To use a single bidirectional motor with the shield, following steps were taken:

  • connect the motor to OUT1 and OUT2
  • connect a power supply (I used 12V/2A)
  • set INH1 and INH2 to HIGH
  • use IN1 for direction 1, IN2 for direction 2

 

 

Two unidirectional motors

 

To use a two unidirectional motors with the shield, following steps were taken:

  • connect the motor 1 to OUT1 and GND, motor 2 to OUT2 and GND
  • connect a power supply (I used 12V/2A)
  • set INH1 and INH2 to HIGH
  • use IN1 to control motor 1, IN2 for motor 2

 

Demo

 

Here's a video of the different modes in action:

 

 

Anonymous
Parents

  • Hi Frederick,

     

    Nice review!! I too have been playing with this board, not written any code for it yet though : )

    The large round pads by the way have a nice use - if you have the right kind of 4mm banana plugs, then they can be inserted, to make it convenient to test the board by connecting it to a power supply and load.

    (or perhaps use nut, bolt and spade or ring terminals).

  • in reply to shabaz

    Hi shabaz, thanks!

     

    Unless the spacing with the Arduino is drastically increased, wouldn't the banana plugs/nuts&bolts be obstructed by the underlying board ?

    USB/Ethernet port obstructing VBAT, ICSP header obstructing motor GND, etc ...

  • in reply to fvan

    That's a good point, I see what you mean. To be honest I don't use the Arduino much, so I plan to use jumper leads to connect the board to the microcontroller. The board has been designed to handle massive amounts of power (for automotive applications) so they went with the huge pads to help those evaluating the device for automotive apps. (the smaller screw terminals won't handle the huge >50A the device can support).

     

    Like you, I intend to use it with much smaller motors than for automotive use (the principles are the same, just our power requirements are lower) so I directly soldered to the pads - the screw terminals you managed to fit in are a nice alternative.

  • in reply to shabaz

    Just a small warning: the devices can go to 55A, but the shield is only suited for 30 A avg (listed in small print on page 3 of the quick start guide)

  • in reply to fvan

    I've posted a mini rant about this board a few days ago.

    The specs of the H-bridges are amazing, the schematic is well designed. But I can't believe that anyone at Infineon has ever asked

    anyone to try the board and get their feedback. I guess that the stacking problem and replacing the cap will become

    a recurring comment in reviews.

     

     

    Just a little more thought in the design and it would have been a gem.

  • in reply to Jan Cumps

    I guess that the stacking problem and replacing the cap will become a recurring comment in reviews.

     

    I think so too, it's just too obvious ... Makes you wonder how this is tested and what assumptions are made.

     

    My extra tall stackable headers should be here on Tuesday I think, let's see what that gives

  • in reply to Jan Cumps

    Makes you wonder if the engineers go out in the real world!?! What a poor solution if you can call it that.

Comment Children
  • in reply to clem57

    Hi!

     

    Probably 'Arduino' is a loose 'standard' if that. The Arduino bit is just to ensure people know what to expect in terms of interface pins and a convenient way to provide source code if needed.

    This board is really just to evaluate the motor controller IC for automotive purposes, and so doesn't need to overly play friendly with boards beyond providing the basic interface. The capacitor is a high voltage (50V) part to be compatible with most motors, but can be replaced with (say) a low-profile 16V one if needed, if another board needs to be stacked on top. The more expensive part they have fitted can then be kept for other needs!

    I personally think the board is quite well designed*, since I can connect up test leads easily using the 4mm holes. By the way, the board will fit many Freescale FRDM boards as-is, with normal sized headers, so even if jumper leads are not used, it will fit some microcontroller boards.


    * Just a personal opinion, everyone will have different needs however.

  • in reply to shabaz

    It is certainly a nice design. The heat management is a school example. If you have the board in your hands, you have to contain yourself or you start drooling - it's done that well.

    But on the other side is presented as an Arduino shield.

     

    I get your comments on replacing the caps - and that is also what and myself seem to have done in parallel without knowing from each other.

     

    And the source code that is advertised in the quick start guide is not there (or at least I cant find it). That's the first thing you look for when evaluating.

     

    I am going to use this board big time. It's a winner with very capable ICs on them. But the story could have been so much more beautiful without additional costs on Infineon's side.

    For the same money, they could have made a slightly smaller board, with the connectors better placed and a different cap.

    On the other hand I'd also like to give them kudos for that cap. It's a nice one from Vishay.

     

    The picture isn't black or white, as always

  • in reply to shabaz

    I totally agree, the board is beautiful and looks well designed (I say "looks" because I'm no expert ).

     

    The feedback will probably vary depending on who's working with it.

    I'm more of an integrator myself, and until now I've been using off the shelf components to build projects. When I get a board like this, even if it is labeled as an evaluation board, I will try to use it in a project and bump into more practical issues. Issues which might not have been taken into account because the board's purpose is to evaluate the functionality of the components on it, not to be used in a project.

    Someone getting this board for the sake of evaluation and ultimately creating a design around those components will probably have completely different feedback.

     

    A question that comes to mind is then: did it have to have the Arduino shield form if meant as an evaluation board? If you label it a "shield", people are bound to try and get it on an Arduino

  • in reply to fvan

    Frederick

    Nice review and great timing.

     

    The price break makes it a very good choice for high power applications (which I have a use for).

     

    The stackability I think is for your small robot ... but then you only get a single bi-directional motor and who wants that....

    The other elephant in the room is that capacitor ...impossible to stack on top of that.

     

    While the shield (and many others) have issues with clearance of the ethernet socket, that design fault lies with Arduino who IMO should have longer header plugs ....

     

    In regard to the hole size, I agree with DAB that it's intended use is remote from the MCU and therefore the wires are soldered onto the board ... at least for 30A applications.

     

     

    I have decided to order a pair to suit my project, as the other boards are larger and have more discreet parts that can produce smoke a lot easier than this will....

     

     

     

    For anyone contemplating this board ...like some other IC Motor Driver boards it's lowest voltage is 8v which means many of the smaller motor/gearbox will not be suitable for it.

    (I also hope the 55A min is a typo as the current limit is 55A which would be a maximum)

     

    Mark

  • in reply to mcb1

    For anyone contemplating this board ...like some other IC Motor Driver boards it's lowest voltage is 8v which means many of the smaller motor/gearbox will not be suitable for it.

    I did manage to find a workaround for that using a 12V power supply and 6V DC motors. I just made sure the PWM signal's duty cycle did not exceed 50%, giving me the required 6V output