Open Source Boards Available, Stepper Drivers and Break Out Boards

[pminmo]

tekno, which files? .zip's need to be opened via winzip or other. .sch and .brd are Eagle files. Eagle is an electronics CAD tool available at www.cadsoftusa.com.
.pdf's are acrobat. .png's are graphics that your browser should be able to handle.

Phil

[pminmo]

It Paul,
I guess I need some further explaination. I'm not understanding your design. I assume it's being driven by a low current bipolar driver, via x1? I don't understand how you will get q1, q4,q5 and q6 to ever turn on?

Phil

[lt paul]

I would apply a logic level voltage to the motor supply inputs of the driver this would trigger the fets to turn on while the inverter holds the other fets off when the coil is inverted the inverter will thun on the other pair of fetsinverting the current flow in the coil connected to the h bridge. if that doesn't explain it maybe i can make a diagram showing the logic levels., tommorow

[pminmo]

IT paul, it's not the logic of the H bridge I don't get. Simply D1 and Q1, at x1-1 if you apply a 5v logic high, assuming Q1 was at 0V previous state (power off). D1 will be reverse biased ! Second question is with x1-1 low, the 7404 will see the low state of what ever is driving X1-1 + D1 Vf, your at best at the threshold of the 7404 input low voltage, and worst case significantly higher than the low level input threshold?

Phil

[lt paul]

thats the kind of thing that i didn't know how to take into consideration, so will some pull downs work? or can i get rid of the diodes? do i need to use buffers? or is this the kind of thing that just wont work. could a pic be used to implement the logic? i dont have any knowledge of the practical implementation side of design, i've built some kits and designed some circuits, but ive never connected thos two dot's so to speak, the closest iv'e come to doing the full design process is design ing a board from a shcematic and then making and testing the board.

[pminmo]

IT Paul,
It's much more complicated than that, the logic is the easy part. I assume your goal is to increase the the drive capacity of an existing bipolar driver? If so is it a chopped driver or steady state? What kind of driver capacity are you looking for? Is there a specific chip or driver you want to "amplifiy"?

Phil

[t_Bendigo]

My compliments to all who are posting to this thread. I have been keeping an eye on it watching it grow and trying to learn in the process. I think Pminmo and Tachus42 deserve a medal. I like the idea of the Chopper circuit but I need a bit of direction on the reference to frequency in your post Tachus42. How does one determine a suitable frequency for operation.. is there a formula somewhere or site I can look it up on. A bit of an ask..could you put out a pdf version of the copper side for the board (three or single axis) or some other format such as png. I used the png format successfully to produce a board for Pminmo's design although haven't finished populating it yet. Thanks again I appreciate your efforts.

[tachus42]

With the chopper higher frequency is better but switching losses and core losses in the motor will increase with frequency. If the frequency is too low there will be audible noise from the motor. I used a 3n3 timing cap on the prototype and it works well I suggest you use this value also. 4n7 should be fine as well.
All the parts for both boards are avalible from jaycar in australia. Use STP30NE06L instead of the IRLZ44 Mosfets.

There is a free version of eagle from http://www.cadsoftusa.com/ it's no problem to download and install. To print the copper pattern I just open the board and turn off all the layers apart from bottom and pads and print. You might need to hit the ratsnest button to get eagle to redraw the polygon areas.

[t_Bendigo]

Thank you Tachus42. As Mr Burns said .. excellent.

Your circuit shows IRF9540 which is a P type Mosfet. I assume that is what you meant as the IRLZ44 and STP30NEO6L are both N types unless I am looking at the wrong board.

I am still a long way off turning a motor but getting there thanks to the help found in this site and others such as the Yahoo site.

[tachus42]

The chopper board uses P Channel Mosfets. The driver board uses the N Channel ones.

[tekno]

Originally Posted by tachus42 There is a free version of eagle from http://www.cadsoftusa.com/ it's no problem to download and install. To print the copper pattern I just open the board and turn off all the layers apart from bottom and pads and print. You might need to hit the ratsnest button to get eagle to redraw the polygon areas.

thanks for the info..

[pminmo]

I updated my webpage to include tach's 3 channel chopper.
http://webpages.charter.net/pminmo/cncelectronics.htm
Phil