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Dc-Dc converter

A

atul

Jan 1, 1970
0
I want a circuit for Switching DC-DC coverter. Input 24 VDC and output
12 VDC 10 amps. Please give me some ideas or circuits.
 
atul said:
I want a circuit for Switching DC-DC coverter. Input 24 VDC and output
12 VDC 10 amps. Please give me some ideas or circuits.
Why wouldn't you just use a solid state voltage regulator IC. They are
ready to go right off the shelf. Something like an NTE-933 will
regulate up to 5amps and if you didn't want to parallel two of these
you should be able to boost the current using power transistors of the
proper size. If you were going to do that you might start with an
NTE-1954 (a 1 amp regulator and cheaper) as your reference regulator
and boost that with power transistors. The whole point is to avoid the
complexity and losses of a DC to DC conversion process. Keep it
simple.
 
J

John Woodgate

Jan 1, 1970
0
Why wouldn't you just use a solid state voltage regulator IC.

How very magenta. (;-) 240 precious watts wasted. The Earth will become
a cinder overnight! (;-)
 
P

PeteS

Jan 1, 1970
0
Why wouldn't you just use a solid state voltage regulator IC. They are
ready to go right off the shelf. Something like an NTE-933 will
regulate up to 5amps and if you didn't want to parallel two of these
you should be able to boost the current using power transistors of the
proper size. If you were going to do that you might start with an
NTE-1954 (a 1 amp regulator and cheaper) as your reference regulator
and boost that with power transistors. The whole point is to avoid the
complexity and losses of a DC to DC conversion process. Keep it
simple.

Because it may be homework. There are suitable circuits in app notes
easily find-able through google at all the usual suspects web sites,
but the professors know all those canned circuits ;)

If the OP is a little more forthcoming on more details (required
transient response, load variations etc.) he may get more help

Cheers

PeteS
 
J

John O'Flaherty

Jan 1, 1970
0
Why wouldn't you just use a solid state voltage regulator IC. They are
ready to go right off the shelf. Something like an NTE-933 will
regulate up to 5amps and if you didn't want to parallel two of these
you should be able to boost the current using power transistors of the
proper size. If you were going to do that you might start with an
NTE-1954 (a 1 amp regulator and cheaper) as your reference regulator
and boost that with power transistors. The whole point is to avoid the
complexity and losses of a DC to DC conversion process. Keep it
simple.

If you use a simple series regulator, you throw away 120W. Adding some
complexity could save some of that power.
 
Why wouldn't you just use a solid state voltage regulator IC. They are
ready to go right off the shelf. Something like an NTE-933 will
regulate up to 5amps and if you didn't want to parallel two of these
you should be able to boost the current using power transistors of the
proper size. If you were going to do that you might start with an
NTE-1954 (a 1 amp regulator and cheaper) as your reference regulator
and boost that with power transistors. The whole point is to avoid the
complexity and losses of a DC to DC conversion process. Keep it
simple.

Getting rid of 24W isn't all that simple. The NTE933 is a linear
regulator.

http://www.nteinc.com/specs/900to999/pdf/nte933.pdf

Simple switching regulators avoid that particular problem.
 
John said:
How very magenta. (;-) 240 precious watts wasted. The Earth will become
a cinder overnight! (;-)

Be your age. Getting rid of 120W without driving a linear regulator
into thermal overload protection is hard work and requires a big
heatsink with a low thermal resistance to ambient, which usually means
fan-blown.

It isn't the earth that turns into a cinder overnight, but the project
costs.
 
J

John Woodgate

Jan 1, 1970
0
In message said:
Be your age.

Why? It's dull being 68 and a bit. I'd rather be my shoe-size (British
size, preferably, but I'll settle for Continental).
Getting rid of 120W without driving a linear regulator into thermal
overload protection is hard work and requires a big heatsink with a low
thermal resistance to ambient, which usually means fan-blown.

Indeed. I abjectly apologise for writing 240 W in error.
It isn't the earth that turns into a cinder overnight, but the project
costs.

You haven't understood a bit, have you? What do you think is the
significance of that odd word 'magenta' in this context? Followed by a
ridiculously exaggerated comment about global warming?
 
John said:
Why? It's dull being 68 and a bit. I'd rather be my shoe-size (British
size, preferably, but I'll settle for Continental).


Indeed. I abjectly apologise for writing 240 W in error.

I've managed to write 24W at another point in the is thread, which was
just as abjectly in error - senior moments seem to start at 63
(possibly earlier).
You haven't understood a bit, have you? What do you think is the
significance of that odd word 'magenta' in this context? Followed by a
ridiculously exaggerated comment about global warming?

Haven't a clue - a google search on "magenta" and another on
"magenta+global+warming" didn't help either. Do tell ...
 
J

John Woodgate

Jan 1, 1970
0
In message said:
Haven't a clue - a google search on "magenta" and another on
"magenta+global+warming" didn't help either. Do tell ...

Magenta is the complementary colour of green - as near to an 'opposite'
as you can get in the context.

I think we should form an International Magenta Party, to combat the
worst excesses of the green movement. You know, opposing the restoration
of a landfill refuse site because it would displace the seagulls [1].

Members would be required to eat five portions a day of magenta food,
with some tolerance on what is 'magenta'. Examples are: red cabbage,
aubergines (eggplants), lollo rosso, beetroot, red grapes, purple
peppers (rare but they do exist), boysenberries....

[1] Far more serious is the proposal from a group of British MPs to
raise the car tax on cars with a fuel consumption that they consider
'high' to £1800 a year, and even family cars would attract £1500 tax.
Considering what that would do to the values of the cars, it amounts to
summary confiscation of assets. Stalin would be proud! Both of John
Prescott's Jaguars would, of course be exempt, as they are 'essential'.
 
John said:
Magenta is the complementary colour of green - as near to an 'opposite'
as you can get in the context.

I can follow the logic.
I think we should form an International Magenta Party, to combat the
worst excesses of the green movement. You know, opposing the restoration
of a landfill refuse site because it would displace the seagulls [1].

If you want my opinion of the worst excesses of the green movement, it
is their tendency to over-state and over-simplify their case. I've
pretty much lost patience with the Dutch branch of Greenpeace -
listening to them is like being exposed to a non-stop TV commercial, a
continuous stream of emotionally loaded non sequiteurs. Worse, my wife
still gives them money ...

Once the rent-a-crowd fanatics latch onto a cause, no matter how
worthy, principle goes out the window. Fundamentalist Christians and
fundamentalist muslims provide endless examples - one of the stronger
arguments against the existence of god is his failure to spend a few
lightning bolts on the likes of Ian Paisley and Osama bin Laden.
 
F

Frank Bemelman

Jan 1, 1970
0
fundamentalist muslims provide endless examples - one of the stronger
arguments against the existence of god is his failure to spend a few
lightning bolts on the likes of Ian Paisley and Osama bin Laden.

Aren't you forgetting someone?
 
J

John Woodgate

Jan 1, 1970
0
dated said:
If you want my opinion of the worst excesses of the green movement, it
is their tendency to over-state and over-simplify their case. I've
pretty much lost patience with the Dutch branch of Greenpeace -
listening to them is like being exposed to a non-stop TV commercial, a
continuous stream of emotionally loaded non sequiteurs. Worse, my wife
still gives them money ...

Beat her.

At Scrabble, of course.
Once the rent-a-crowd fanatics latch onto a cause, no matter how
worthy, principle goes out the window. Fundamentalist Christians and
fundamentalist muslims provide endless examples - one of the stronger
arguments against the existence of god is his failure to spend a few
lightning bolts on the likes of Ian Paisley and Osama bin Laden.

I entirely agree with you. That must be a nice change, seeing how almost
all of your posts are received. (;-)
 
J

John Woodgate

Jan 1, 1970
0
dated said:
fundamentalist muslims provide endless examples - one of the stronger
arguments against the existence of god is his failure to spend a few
lightning bolts on the likes of Ian Paisley and Osama bin Laden.

Aren't you forgetting someone?[/QUOTE]

Phat Thingy? No, I don't support the summary execution of imbeciles.
 
J

Jim Thompson

Jan 1, 1970
0
Aren't you forgetting someone?

Phat Thingy? No, I don't support the summary execution of imbeciles.[/QUOTE]

ROTFLMAO!

...Jim Thompson
 
M

martin griffith

Jan 1, 1970
0
Aren't you forgetting someone?

Phat Thingy? No, I don't support the summary execution of imbeciles.[/QUOTE]

So at what IQ can you perform summary execution?


martin
 
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