What diy bipolar driver board?

[masterx81]

This is my first post, so... Hi to all! :-)
Forst of all, congrats for this nice board! It's amazing!
I'm starting now my first cnc project, and i'm finding the first throubles...

I need a little help, as i have some troubles finding the right controller board for this stepper motors:
http://cgi.ebay.it/ws/eBayISAPI.dll?...MEWN:IT&ih=020
I want to drive them as bipolar...
But i really not say where to find a driver board capable of 40/50 volts and 4.6 amp...
I was thinking to go with a l6203 driver board, but it will be a little 'overwhelmed'...

I can do smd, produce myself boards, etc...

Any suggestion?
Really thanks to all!

[blackbeard52]

www.pminmo.com

[masterx81]

Sorry, but i not see anything that can be useful to me...

[blackbeard52]

I felt Phil would probably the best choice to lead you in the right direction...He is the DIY driver board guru.

Good luck
Bob

[pminmo]

I've not posted a L6203 board as I've not been able to capture what I think is a pcb that a person using toner transfer can do easily. If you just want a schematic?

[masterx81]

Originally Posted by pminmo I've not posted a L6203 board as I've not been able to capture what I think is a pcb that a person using toner transfer can do easily. If you just want a schematic?

Hi! First to all, thanks for the help!

If i go with the way of l6203 i suppose that i do the following board:
http://www.cnc-dag50.it/content/view/21/39/
(Thanks to the work of DAG50!!!)

I have 4.6a motors, driving them at 4.0 amp that the 6203 is capable, i suppose that i lost a lot of torque... Probably this motors in any case are too much for my application, but i prefer to drive them at full power...

It's possible to match a l297 with 2 H-bridges done with 8 separate mosfets?
As in this way, i can put what mosfets as i prefer (easy to obtain 5 amp/phase), and probably half step it's enough for my application...
Else, any alternative to l297 that can also do microstepping?

Really thanks!

[pminmo]

A L297 could be used to run a discrete mosfet circuit, but you will need mosfet drivers also. 8 mosfets, 4 half bridge drivers like the irs2104, plus support circuitry.

[masterx81]

Originally Posted by pminmo A L297 could be used to run a discrete mosfet circuit, but you will need mosfet drivers also. 8 mosfets, 4 half bridge drivers like the irs2104, plus support circuitry.

Looking for convenience...
L6203 are limited at 48v (some that have already used them has said me that in any case over 40v they burn...) and 4a phase. and they costs 6€, 12€ per channel.
An irf520 is rated at 9.2a, 100v, 0.270ohm... With recirculating diode already built-in... Cost near 0.75€ cad, near 6€ per channel, plus the cost of the half bridge driver (i'm wasn't able to find it here in italy...).
Pluse the costs of some logic gates (for example here http://www.cnczone.com/forums/showthread.php?t=9145 , but also on the l6203 datasheet there is some control logic explaination...).
Plus some resistors and capacitors... A little more complex, but much more flexible.
Remain the doubt if there is a controller similar to the l297 that can handle also microstepping (sometimes the half-step of the l297 isnt' enough...).
Problably also the l297 can be exchanged with a programmed microcontroller... (Linistep?, picstep? They can do the job?)

Do you think that can be a doable road this?
Or probably is better to abandon all hopes?

I've seen a complete lack of diy drivers that can handle that currents...
And i haven't money for pay a professional driver...

[pminmo]

Sure it's doable, but the issue isn't the circuit design it's the physical implementation of a pcb that DIY'ers can do. The more complex the circuit the more difficult it is to implement physically. As to microstepping biolar chips as an all in one solution with external mosfets, can't say I know of any I would recommend. A lot of us thought the Allegro A3986 was the ticket a year plus ago, then as a number of us looked to mplement we found a similar issue in unique designs, the step angle accuracy was a problem. Turns out the fixed off time ratios of the chip, and the way the chip comes out of blanking and doesn't sense over current if that happened during blanking is a problem. After being lead along by the Allegro engineer for month's they finally fessed up to the issue. The A3985 is better but you will have to put a micro in front of it and do the software.............and it exhibits some of the same issue, but timing is more programmable, so there are variables that can work out for a portion of applicatons.

[masterx81]

Originally Posted by pminmo Sure it's doable, but the issue isn't the circuit design it's the physical implementation of a pcb that DIY'ers can do. The more complex the circuit the more difficult it is to implement physically. As to microstepping biolar chips as an all in one solution with external mosfets, can't say I know of any I would recommend. A lot of us thought the Allegro A3986 was the ticket a year plus ago, then as a number of us looked to mplement we found a similar issue in unique designs, the step angle accuracy was a problem. Turns out the fixed off time ratios of the chip, and the way the chip comes out of blanking and doesn't sense over current if that happened during blanking is a problem. After being lead along by the Allegro engineer for month's they finally fessed up to the issue. The A3985 is better but you will have to put a micro in front of it and do the software.............and it exhibits some of the same issue, but timing is more programmable, so there are variables that can work out for a portion of applicatons.

I've seen you thread... No way for cnc application with the allegro chip...
So, the more stable solution, as now, it's the l297...

For the complexity of the circuit, leaving the driver as modular, i suppose that the board will not remain that complicated (surely more complicated that a l297/l6203 board), but in that range of currents (more than 4a in bipolar), there isn't nothing in the diy world, so a little bit complicated circuit it's still better than nothing :-)

Searching a little more, i've found that probably i need a charge pump for the high sider drivers, to get them fully opened... This i suppose that mean also 'at least' a charge pump and a 555 to maintain the Vgs at least of 10v, right?

After more reads... Devices like HIP2100/HIP2101/lm510x and probably others already do bootstrap (i've not found in the pdf if the irs that have you posted can do the bootstrap).

Whop, the hip miss inhibit pin...
The L6384 instead seem a good cheap candidate...

I wasn't able to find here the irs!!!

I'm a newbie in mosfet designs... i need a little more reading :-)

[pminmo]

Doesn't look like that chip can disable both mosfets? The IRS2104 is the new PN for the old IR2104. Yes the drivers need an integral charge pump, and if the circuit guarantees a chop cycle for the charge pump timing, depending on capacitor values mosfet characteristics the 2104 can maintain the charge pump voltage.

[masterx81]

Originally Posted by pminmo Doesn't look like that chip can disable both mosfets? The IRS2104 is the new PN for the old IR2104. Yes the drivers need an integral charge pump, and if the circuit guarantees a chop cycle for the charge pump timing, depending on capacitor values mosfet characteristics the 2104 can maintain the charge pump voltage.

I wasn't able to find neither one of the previous drivers, but i've found this (With SD pin for shutdown):
http://www.alliedelec.com/Images/Pro...s/273-1554.pdf
for 2,75 € CAD, so 11€ per driver... Not that bad... + 4.56€ for the mosfets (i've found a place where the irf530 are cheaper than the previous irf520!) and some other for the external components... I suppose that the price will remain nearly the same as the 6203 configuration, with much more power...

---EDIT---
Wow, i've found IRS2104PBF at rs-components! Shipping costs are quite expensive, but for a quantity of at leat 10 items, they costs me 1.70€ cad, so there is some convenience (also that this has 8 pin, so smaller board...)

I'm missing something? Some errors on the choosed components?

Really thanks!