Electronics Experts

[Dink]

any one here got anything that they could email me or something

to help me build a 30A 15V 1kHz PWM controller.

i know it's a bit of a long shot LOL but worth a try

 

[biojo]

guesing u`ve tried google ,

http://www.fairchildsemi.com/ds/FA/FAN4803-2.pdf

duno if n e of them are usefull,

 

[Dink]

the last one is close but it looks like it also includes a smps and only does 20A.

 

[biojo]

a man of yer talents should be able to correct that, whats this project for ?

 

[Dink]

ahhh now that would telling

(it's to control a TEC in a little project i got brewing in my mind lol)

give me 400v 230v 110v and i know what i'm doing but electronics is a bit beyond my skills

 

[Lagerlout]

Deffo. Give me 11kv any day. Gentlemans elctricity. lol.

What you going to be driving that needs 30A?

 

[Dink]

a TEC

yes 11Kv is defo gentlemans electricity (out of my league{sp}lol)

 

[sn00p]

There are some very specific opamps you can use for this, I can't remember the manufacturer off the top of my head. We used them for a 40A 5V controller.

They're very expensive and require a massive heatsink!

 

[skinner]

A thermoelectric cooler?

 

[Dink]

yep thats what it's for.(a 62mmx62mm one)

i've found this but i'm not sure if it's just scaling it up

 

[skinner]

The one with the saw tooth looks OK. You could pretty much take it as is, but change the output circuit.

The 555 timer one, I'm not sure how stable the frequency will be.
Is the cooler any good? I've used a couple of supercool ones, and for the power consumed you don't get much cooling! Useful for mini fridges/small enclosures, but not much else.

Do you want climate control, or are you happy with a cold/colder pot? If so I would just buy a controller from the manufacturer and save some hassle.

I was going to use one of these, but just ended up running it flat out.

http://www.supercool.se/default.asp?viewset=1&on=Products&initid=37&mainpage=catalogue/catalogue_list.asp?mid=14||sid=35

 

[skinner]

By as is, I meant change the component values on the saw tooth bit to get 1Khz, and change the reference voltage resistors so that you can get 0-100% duty cycle.
Usefully he has put no formulas on the site!
the frequency is f= (1/4CR1)x(R2/R3)
R2 must be bigger than R3
(found from other sites not my head)

 

[Dink]

yeah i was going to control it with reference to the temp of the hot side heat sink.

it is just going to be used as a cooler and not a heater.

i bought the cooler off ebay it seems ok not got it set up yet to put any sort of current through it yet.

 

[sn00p]

dug up one of the op amps at work today....

it's a PA50. linky

These things are awesome. It still cracks me up when I see the heatsink attached to them because it's massive - we also ran fans over the fins as well!

I should post a picture of the development instrument, it's pretty impressive and not something you'd want to poke your fingers into!

 

[Dink]

this circuit any better?

that is one meaty op amp.i'm just looking for a op amp to control a MOSFET lol