[LVMarc]

Hi

Do you know any sites, where I can find info how properly design a low
power (about 5W) flyback power supply? I add that I'm beginning with
switchmode power supplies.

Most of te semiconductor houses now have online or downloadable circuit
cimulators and tools. For switch mode power supplies Linear technology
is a well known suplier and they have a LT switcher tool. so may as well
start there.

The key to all switchmode is sizing the inductor for correct value at
full current load (current de-magnetizes the coil, saturation effets)
and then sizing the capacitors to limit ripple. The rest is finese. You
wil also nee a good supply of schottky diodes tha also handle peakswitch
mode currents.

If you need help for a commmecial product let me now and our group will
put together a professinal supply and source the materials you neeed
along with manufatring acument.

IN any event have fun and good luck

Marc

 

[Klaus Kragelund]

Firs of all, thanks for quick answer...

Power supply will be the part of biger student project so I don't want to
use a specialistic chip in design. I was thinking about simple PWM generator
with comparator (like UC3842).

--
Best regards,
Marcin Osiniak- Skjul tekst i anførselstegn -

- Vis tekst i anførselstegn -

Look at the TI site (Formerly Unitrode application notes and papers
give great info)

Regards

Klaus

 

[Eeyore]

Hi

Do you know any sites, where I can find info how properly design a low power
(about 5W) flyback power supply? I add that I'm beginning with switchmode
power supplies.

www.powerint.com

 

[Marcin Osiniak]

Hi

Do you know any sites, where I can find info how properly design a low power
(about 5W) flyback power supply? I add that I'm beginning with switchmode
power supplies.

 

[Marcin Osiniak]

Most of te semiconductor houses now have online or downloadable
circuit cimulators and tools. For switch mode power supplies Linear
technology is a well known suplier and they have a LT switcher tool.
so may as well start there.

The key to all switchmode is sizing the inductor for correct value at
full current load (current de-magnetizes the coil, saturation effets)
and then sizing the capacitors to limit ripple. The rest is finese. You
wil also nee a good supply of schottky diodes tha also handle
peakswitch mode currents.

If you need help for a commmecial product let me now and our group
will put together a professinal supply and source the materials you
neeed along with manufatring acument.

IN any event have fun and good luck

Marc

Firs of all, thanks for quick answer...

Power supply will be the part of biger student project so I don't want to
use a specialistic chip in design. I was thinking about simple PWM generator
with comparator (like UC3842).

 

[John Larkin]

Firs of all, thanks for quick answer...

Power supply will be the part of biger student project so I don't want to
use a specialistic chip in design. I was thinking about simple PWM generator
with comparator (like UC3842).

I posted an inverting switcher, essentially a flyback, schematic to
a.b.s.e. a week or so ago. I like this design because it is sort of
discrete. Something similar could be done with all transistors, no
IC's at all, without much difficulty. The IC I'm using is just a gate
driver with hysteresis, not intentionally a switching controller.

The really interesting issue is control loop stability at various
inputs and loads, especially in continuous mode. My struggle with
capacitor esr and such has been a running thing here.

John

 

[Hammy]

Hi

Do you know any sites, where I can find info how properly design a low power
(about 5W) flyback power supply? I add that I'm beginning with switchmode
power supplies.

The app note on the UC384X has a good design example on a multi output
FlyBack.

For other SMPS stuff check here.

http://www.smps.us/ <-Unitrode power supply seminar other stuff.
http://perso.orange.fr/cbasso/Spice.htm <- Basso has some ready made
spice examples (including the UC3844)

Also check manufacturer's web sites they all pretty well have online
line tools to help in the design process.

 

[Robert Baer]

Most of te semiconductor houses now have online or downloadable circuit
cimulators and tools. For switch mode power supplies Linear technology
is a well known suplier and they have a LT switcher tool. so may as well
start there.

The key to all switchmode is sizing the inductor for correct value at
full current load (current de-magnetizes the coil, saturation effets)
and then sizing the capacitors to limit ripple. The rest is finese. You
wil also nee a good supply of schottky diodes tha also handle peakswitch
mode currents.

If you need help for a commmecial product let me now and our group will
put together a professinal supply and source the materials you neeed
along with manufatring acument.

IN any event have fun and good luck

Marc

BUT.
*ALL* of them are totally useless for (truly) high voltage output
(say 400V to 40,000V).
These daze, "high" voltage is anything over 30V...

 

[LVMarc]

BUT.
*ALL* of them are totally useless for (truly) high voltage output (say
400V to 40,000V).
These daze, "high" voltage is anything over 30V...

Rob,

I have never tried the web based tools for anyhting but a qucik look and
only at becnch top levels ...a could of f\vp;ts.. latley 3 volts is the
high voltage and things go down from thier! I did ot relaize the web
tols had voltage imts.

for srius simulation I waould use pencil and papaer along with a spice
for the core elements, there are no similar voltage l

Marcimts there