Maximum power of flyback
I have heard it said on this forum that the maximum power capability of a flyback is "200W or 5A"
However, RDR203, on page 21 states that if the DC bus can be maintained higher, then more power can be gotten from this flyback......but how much more power do you mean?
Comments
Waiting for your reply.
sandeep Dalwaria
hello Sandeep,
You get better answer for your general question at edaboard.com
hi,
for each output:
1. calculate the load resistor value: Rload=Vout/Iout
2. calculate the total power rating of the resistor: Prating=Vout X Iout
3. it good practice to double the power rating: P of Rload = 2 X Prating
4. build resistors in series or parallel to get Rload value
other tips:
1. wirewound resistors are generally used for smps loads
2. forced-air cool your Rloads, keep them under 75°C.
good luck.
You can design a flyback with any output power capability.
In the real world, cost and efficiency are some of the constrains to limit the implementation of high power flybacks to marker.
There is not a well defined barrier that marks when to use a fyback or a forward or any other topology. if your design is about 100 watts, You may consider use a forward topology instead of a flyback.
You will know what is better for you after you compare both designs and select the design that is better fit for your needs
yes but realistically ,above 250W, and a flyback from 90VAC input is going to need a fan.....and you are not going to choose an smps that needs a fan...so there ARE limits after all...surely you agree/?
treez,
Fan vs. no fan is just one of the many engineering tradeoffs a system and SMPS designer must make. There are cost and spec implications.
I see what you mean, of course, as you know, if i select a flyback , and the FET junction temperature is >120 degrees with the best thermal layout possible etc , then i need a fan, and theres no way round that......so what i am saying is, that fans are expensive, and it surely is virtually always best to selct a topology that is not going to need a fan.
That is not correct.
There is a reason some PSU applications use fans and some don't. There are cost tradeoffs and reliability/life tradeoffs. Some applications cannot tolerate forced air due to envirnonmental dust and dirt (e.g. street light)
Fans are not expensive. No fan means a more expensive topology and heatsinking. Big extruded heatsinks are more expensive than fans.
Derar sir/ Madam
I want make a load box please guide me which components and rating is required.
The output Voltages/current of SMPS Is given below
5V DC/30Amp
12V DC/6Amp
24V DC/9.5Amp
-12V DC/1Amp
sandeep Dalwaria