Hi Guys,
My last post subject should read design advice required.
Best regards
		Luis 



-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf
Of Luis Moreira
Sent: 21 March 2006 12:33
To: Microcontroller discussion list - Public.
Subject: RE: [EE] Watercooler - revisited

Hi all,
I am in the process of upgrading one of our systems and the bit I am
looking at the moment has 24 IGBT H bridge modules. Each of these
modules as a driver board which I need to replace. This board will need
+ - 15V at steady current of around 300mA ( when switching IGBTs current
will be sourced from local storage caps).The IGBTs will be switched at
frequencies up to 350KHz. My biggest problem is how to supply power to
the boards as they need to be isolated from the rest of the system
(sitting at HV). The solutions I found are:

- Fit an of the shelf isolated switching power supply which seems good
but probably the price and possible problems with switching noise makes
this solution not a very good one.

-The other which was suggested by a friend is to supply the board with a
40KHz at around 20V peak sinusoidal generated by a resonant circuit.
this would reduce the size of the transformers on the boards. Voltage
would then be rectified and regulated.

Any ideas welcomed
Best regards
		Luis     


-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf
Of Alan B. Pearce
Sent: 21 March 2006 09:33
To: Microcontroller discussion list - Public.
Subject: Re: [EE] Watercooler - revisited

>> To me the obvious item for this is some plastic cased
>> transistors glued to the pipe. Maxim (and probably
>> others) make chips for PC processor temperature
>> management that handle these using SMBbus IIRC.
>
>Do you mean just using the natural TC of the transistor?

Yes.

>Do you know any part numbers for these parts?

Oh, (much digging through messy pile of product announcement sheets).
Right,
found what I was looking for. Check out MAX6678, MAX6641/3 which use a
bipolar transistor which is embedded in the CPU die for processor
temperature control. There is also MAX6699 (which is definitely SMBbus)
to
handle 4 external diode sensors, plus one on chip.

Also look at MAX7500/1/2 which are I2C devices described as "improved
LM75".
Another possible might be Dallas DS600.

You would probably get enough of these through the sampling program for
your
project, especially if you max out on each of similar devices such as
the
MAX7500 family.

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