Upping the capability of a 5804 IC

[xairflyer]

I have a driver board made up using a 5804 that I am experimenting with.

The IC can drive 1.25 amps on it's own but I have found anymore than 1 amp it gets fairly hot.

I was going to add power transistors or fets to the outputs so I could drive larger steppers, anybody got any views on this ?

[ballendo]

Originally posted by xairflyer
I have a driver board made up using a 5804 that I am experimenting with.

The IC can drive 1.25 amps on it's own but I have found anymore than 1 amp it gets fairly hot.

I was going to add power transistors or fets to the outputs so I could drive larger steppers, anybody got any views on this ?

Hello,

Piece of cake. Done all the time with the 5804; it's even on the datasheeet. LOTS of mfrs. use the 5804 for it's translator, and up the drive capability with external drivers...

Hope this helps,

Ballendo

[xairflyer]

I looked at the data sheet and see the "typical output driver" circuit but could not figure this out as the outputs will be low/negative and it shows an npn transistor, I would have thought you would need to be switching a pnp transistor.

[ballendo]

Xair,

Go to www.cnconabudget.com Cursor down the page awhile to the "freebies" section.

There is some GOOD info there on how to use a 5804 with external transistors...

Hope this helps,

Ballendo

[HaWee]

Ballendo,

I looked at your recommended site un der the freebies section.
But beeing a total newbie in electronics I don't understand his explanation.

I first wanted to use e schematic that only uses TIP120 transistors, but then only little software can be used, because I use 4 channels per stepper. (most software only pulse and direction)
Now I am also thinking of using the UCN5804 for translation in combination maybe with TIP120....But HOW to connect those???


pls help

[Urgundiz]

xairflyer, hawee, you need something like this, only replace TIP110 for TIP120 or 121 for 5A, or other for more amps. do not forget diodes.

hope it helps.
/U

PS: the 7404 buffers the output (not really neccesary) but also cleans the signal, so maintaining it maybe is a good idea..

[HaWee]

Thanks Urgundiz,

I was also figuring out something like this today, but then using TIP125 (PNP instead NPN transistor)...

The part before the UCN5804 I want to use the schematic of
http://www.electronics-lab.com/projects/pc/008/

3 axis controller with home switches and limit switch.

Do you think it would be a good idea to use thin in combination with your part?

[Urgundiz]

The schematic you say sink current to the 5804 (from the diodes direction) and has good info about how to hook to the LPT port.

It seems it will work if you tie the base of the Tip125 to where the diodes are. Put diodes between emitter and colector of the tip125. Better if fast diodes, for example BYV27 ones. Do not forget your ballast resistors betweeen V and stepper winding and the other stuff. The sequence will be, in essence: V, Rballast, Stepper winding, TRN Emitter, TRN Collector, Ground.

Sorry but my Eagle soft just blowed so i can't attach a schematic.

Hope it helps
/U

PS: Sorry for my bad english.. is 'blowed' or 'blown'?

[davesaudio]

I think you need some pullup resistors on the inverter inputs

[ballendo]

Hello,

If you're going to use the 5804 by itself, don't use the series diodes as shwon in the link above. Instead use diodes which shunt to ground, as shown in the 5804 data sheet...

This means you have four diodes, all connected to ground at their "banded" ends, with the "other" end of each to one of the 4 5804 outputs. Your motors will turn faster this way...

Next, if you're using a buffer, use a 7414, which has a schmitt output. This will clean up the 5804 pulses before you send 'em to the tip120's, or fets (Irfl44z or equiv work well).

Hope this helps,

Ballendo

[ballendo]

OOPS!

Here's a correction!

Originally posted by ballendo
[This means you have four diodes, all connected to ground at their UNMARKED ends, with the "BANDED" end of each to one of the four 5804 outputs. Your motors will turn faster this way...

Ballendo [/B]

Also, here's the url for the 5804 datasheet:

http://www.allegromicro.com/sf/5804/

[ballendo]

And a bit more...

Using 1n400X diodes will also slow you down. These "rectifier" type diodes are not fast. 1n4934 or 1n4936, or MR851's are MUCH better. And if you use fets, you won't need output diodes at all due to the intrinsic diode you get "free" with a fet. (Just use a fet with a high amp rating, at least double your motor voltage. Like the ones I posted.)

Ballendo