25 Jun
2013
25 Jun
'13
11:34 a.m.
On 6/24/2013 3:01 PM, Tony Duell wrote:
While I would use a switching _regulator_ for that +%V line (as, indded,
Commodore did i nthe C128 PSU, I've had one apart...), I think a mains
transofmrer followed by a simple switching regualtor woudl eb efficient
enough.
As for 'last longer' Let me ask just how many mains transofmers you've
had to replace in clasisc ocmputers. And how mw many chopper transisotrs.
Give then the designs with mains transofmers are likely to be older, I
think that will answer the question...
[Cost]
Why? Efficieincy, or is there some other reason?
Efficiency, primarily, and the implications (smaller size, runs cooler,
hopefully last longer, etc.) Well, some in the community would argue that finding a
way to make a
$200.00 PSU for a vintage PSU is not really a solution, as anyone can do
that, by buying premade PSUs and putting them in a large enclosure.
The point is you should come up wi tha solid, relaible, designm, and use
that as a basis for the cost. Not cut evey corner you can.
But, I thought as you did. Get the 9VAC at 45VA, and rectify the 5V out.
But, I am having a hard time finding a suitable base PSU to buy.
It may not exist as a ready-made unit. But the trhasnformer is standard.
And I suspect maiking a 5V 5A swithcing regualtor to run from a 9V input
is posisble iwth any of the standard swithcing regualtor ICs.
as a "You build it at your own risk",
it's still a liability. And, I
have to consider the many ways people will try to mess it up.
I sometiems wonder how we all survived 40 eyars ago.... I was wiwing up
mains transfomers when I had a single-digit age.
-tony