Hi,

I'm in need of some MOSFETs.

I need both P and N channel, ideally "matched". (Similar ratings, don't need to be perfectly the same.)

The motor I'll be driving is:
http://www.arceurotrade.co.uk/projec...420484610M.pdf

Note that the current rating, 1A/Phase, is per phase and will need to be doubled. I.e. 2A.

The motor will be controlled through PWM at around 20-35KHz. The driver will be of H-bridge design, if that matters.

A low Rds would be nice.
A gate voltage of either 5V or 12V would be nice. (Either are fine, or within that range.)

The MOSFETs MUST be quite cheap and available in the UK. (Or shipping to the UK is cheap.)

I did look at part number LMD18245, but at £10 each it's way too much. I need 6 pairs of these.

I also need a MOSFET pair for these motors:
http://www.arceurotrade.co.uk/projec...570764525M.pdf
(2.5A/Phase, so 5A.)
I need 12 pairs of these, so obviously it's even more important for these to be cheap.

Thanks for any help,
-Andrew.

 

No ideas ?

I had a look into using just N channel with a driver, but came to the conclusion that it's not suitable for my application due to the switching losses.

 

I've found some MOSFETs. IRF540N and IRF9540N - Both sourced from Hong-Kong for quite cheap.

 

 

Thanks for the suggestion, but is there a higher voltage version of around the same current ? (Maybe 40V ?)

Looks like nice unit to use for cheaper lower-price drivers though, so cheers.

 

Here's a couple Core Electronics - Logic FET's / High Power Switching

They ship worldwide ($10.30 to the UK when I entered it)

__________________
Spency.

PIC Micro's - Your mind is the limit

PIC's and interfacing with other devices - a PIC Basic Guide @ digital-diy.net

 

The link wouldn't work when I just tried it but I'll try it again when I get back home, cheers.

 

I've got a load of IRF540 (which ironically I'm using a load for Stepper motor control ....).

You'll find them on my online shop - Picbits

You might also want to consider some of the Intersil chips for driving the H bridge - I'm using the HIP4080A to drive a bank of 4 N Channel IRF540 per phase - makes life a whole lot easier as they have dead band delay built in.

My end result at the moment is a direction input and an enable input which can be used for the PWM

 

Depending on how much you charge for postage, you may actually be slightly cheaper than the Ebay supplier that I bought mine off. Shame you don't have the IRF9540, mind.

The problem with thouse drivers and using just N channel MOSFETs is that those drivers use a charge pump to generate the high gate voltage. This supply usually doesn't have much current and hence the turn on time is slower. The problem with this is that I wanted to use PWM and this would increase heating.

I'll be using the PWM hardware from a pic though, so that has adjustable deadband stuff built in. Thanks for the suggestion though.

Looks like you've got a reasonable stock of other parts as well, in small quantities - I'll be sure to remember your store.

What would be really nice is if you could supply SMD LEDs of all colours. (Or atleast the main colours.)


That Core Electronics link is working now, those MOSFETs seem a little expensive - Thanks for the link though.

 

I charge £2.99 for P&P for any quantity of items up to £30 then over that its free postage.


All the stuff I sell on the site is stuff I have in stock - I've given up ordering in stuff for people as it tends to hang around and not get sold. The stuff I have is stuff I use myself and purchase in large quantities so I get a better price. What I make from the web sales I plough back into my business for the development side

Dom

 

That's fair enough, any ideas on where I can get SMD LEDs in different colours ? (Ebay has very few different colours.)

 

Electronic components distributor. Electronic equipment and electrical components from Rapid ?

As for your stepper motor, it can be used in either bipolar or unipolar mode. In unipolar mode you can just drive the windings using N channel fets in the correct sequence.

In fact - those motors are an ideal candidate for the Linistepper controller - microstepping and less than a tenner a board to build up.

I'm designing a bipolar stepper controller at the moment with PWM current limiting but thats only because all the motors I've got are bipolar only - if I'd have had the choice and money I'd have gone for the unipolar motors.

 

Oh, didn't realise that Rapid sold SMD parts.

I'll be using the motors in parallel, for torque. For that reason I need to use a bipolar driver.

It's a shame that the Linistepper controller is unipolar only, for it's price.

Cheers for your help.

 

No problem

Just been playing with my new driver - two driver ICs and 12 mosfets later (after getting over ambitious and trying to get it to drive a load way too large) I've got it going nicely.

Just got to wait for my 18F4431's to turn up then I can see if it all works properly. Currently got it driven off an 18F1320 just to test the PWM and its driving a couple of car bulbs.

 

Of course:
Digi-Key - FDS4559CT-ND (Fairchild Semiconductor - FDS4559)

I just looked for the best price there based on your current requirement