Help! DIY 4 amp L297/6203 driver

[irving2008]

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I have a slight concerna about using the PWM - if the PWM controls the direction control (i.e. oscillates between output 0 and open-collector), then that would be fine. However, from memory, it'll only oscillate between 0 and 1, then you'd need to be careful of the PWM pulse width - you could end up going too high with the VREF signal. Still doable though.

There's nothing stopping you from putting it on a separate board.

Depends on the chip and whether an O/C output is available. If not, a single NPN small signal transistor and base resistor on the output would suffice.

Having said that, if you are using a transistor, why not put a trimmer on the output side and not use PWM at all... would simplify the code and you could adjust the holding current to your hearts content.

[Ross77]

Thanks graffian, I think I was about to make that mistake. I'll have to look for that thread, will it still apply to the L297?

I can do the conversion of the schematic

I will definatly take you up on that offer, If you make the board bigger than 4"x3" will i be able to veiw and output it myself? Good info on the PCB fabrication but think it will be too costly for a one off, as i plan to mill future pcbs.

I actually meant discuss with Irving

You've got me sussed, I'll go and sit in the corner then.:heehee:

a single NPN small signal transistor and base resistor on the output would suffice.

Wouldnt this then be the same as using a 555?

[graffian]

Thanks graffian, I think I was about to make that mistake. I'll have to look for that thread, will it still apply to the L297?

From what I remember, Mariss had just noticed the A3986 thread and it started with a comment he could programme a CPLD, pretty much as the gecko stepper drives minus mid band resonance, to do what the A3986 was meant to do. Then another post suggested he would be able to sell them for $5! I imagine you would drive bridge drivers[ir2184?] from the cpld?

[tribbles]

I will definatly take you up on that offer, If you make the board bigger than 4"x3" will i be able to veiw and output it myself? Good info on the PCB fabrication but think it will be too costly for a one off, as i plan to mill future pcbs.

I'll try to fit into 100x80mm (this is the maximum size for the free version). However, I think you would be able to load the larger size in, but you probably won't be able to move the components that are outside the area around.

There are techniques to squeeze it into a smaller space, but I'll avoid them (basically, moving to surface mount components) unless you've got a particular desire to solder really small components

Send me a PM (let me know when you've done it - I think the last one didn't arrive), and I'll give you the details. I can have a rough idea as to whether it'll fit or not probably in an hour or so.