Best AC-DC power supply solution: 12V 1A

We have several product lines that will meet your basic needs: TinySwitch, TopSwitch and LinkSwitch-HP.  All three can meet your general requirements but as usual it's the details that will really matter.  Do you have any other specific requirements?  Some requirements that come up might be no-load input power, transient load response, primary side vs secondary side feedback, topology, etc.

I would highly recommend reading up on the three products I suggested as well as downloading our PI Expert software which will help automate much of the design process using our products.

If you have any further questions, please let me know.

Regards,

The Traveler

Thanks for the reply.

Other requirements might be PSR (Primary Side Regulation) to simplify the design and improve reliability with less components.

But the main constraint is transformer size. The power could be resized to 9W (12V, 0.75A).

The larger transformer size I can use is a EE16 or a EPC17.

I have been trying to use PIExpert software but I can't seem to get a possible design (without errors) with LinkSwitch-CV or TinySwitch III, which are the families it sugests.

Can you give me some extra help? 

If you need primary side regulation, LinkSwitch-HP is going to be the product you need to look at.  LinkSwitch-CV won't be able to get up to the  12W you're requiring but you should be able to get close to the 9W spec.  I would still recommend going with LinkSwitch-HP though.  I don't have time right this second to give you a preliminary design in PI XLS but if I get some time a little later I will see what I can put together for you.  In the meantime, I would really recommend takeing a look at some of the reference designs we have for LinkSwitch-HP and LinkSwitch-CV.

Regards,

The Traveler

Thanks for taking some time to check my design.

I would like to ask you to do it the other way around: Take a EE16 or EPC17 transformer and get a design with the most output power possible.

This design is to be inside a E27 light bulb, hence the size limitation. 

Is this an LED lighting application?  

If so, please let me know your specs.

Regards,

The Traveler

Yes, it's an LED lighting application.

RGB, 60W equivalent luminous flux, remote control of color and brightness.

My approach was to have AC-DC isolated flyback to produce 12VDC. Then use 3 separate/independent DC-DC led drivers.

I would probably recommend using LinkSwitch-PL for your power supply.  If you're using some kind of uC for changing brightness and color, you could use (possibly...not entirely sure here) use a programmable resister to adjust the output current setting of the LinkSwitch-PL power supply.  Adjusting the output current would give you control over the LED brightness.  If you had different color LEDs in series strings, you might be able to have the uC use FETs to short LEDs that you don't want lit.  This would allow you to selectively turn off LEDs in the string. 

Regards,

The Traveler

Ok. And where would I power the uC from if all leds are off?

And if I need isolation? 

logicnibble - 

Since your project sounds a bit more complicated than your run of the mill LED driver or CV power supply, can you give me a bit more information about what you're trying to accomplish?  What have you figured out for your design so far?  What functionality do you need from the power supply?  Etc.

Regards,

The Traveler

Ok:

-Constant Voltage Power supply with isolation - flyback.

-DC-DC led driver

-uC to control led brightness and color using PWM.

So, I was looking for a CV flyback power supply from Power integrations that would fit inside an E27-A19 light bulb.

I should've asked for a solution (IC+transformer) that would have maximum power capabilities and would still fit the E27-A19 light bulb.

As for the power needed, I am still studying 2 options: 12V 0.7A or 24V 0.35A, both 8.4W. 

logicnibble - 

Ok, based on what you're describing, I think the guys in the LED lighting forum would be of better help.  

With your size constraints being a big factor, you're going to want to accomplish as much as possible with as few parts as possible.  So instead of using a AC-DC flyback and then using a DC LED driver, I would just go with an AC-DC LED driver IC.  Our LinkSwith-PL and LinkSwitch-PH product lines would both be suitable for this.  If you go with just a AC-DC flyback supply it's going to be REALLY difficult to get the PF you're looking for, to meet your harmonic requirements, THD, etc.  Also, processing your power twice is going to reduce efficiency and increase complexity.  It'd most likely be easier to use an IC specifically aimed at providing a CC output and then add an extra secondary winding to power your uC.  The second winding  wouldn't have the best regulation, so you'd need to add a linear regulator but I think this would be a lot simpler oveall.

Regards,

The Traveler