[Q] 65W adaptor for notebook?

Thank you for your advice, which is topology, safety, experience about PI, and margins, clearance distances, and triple insulated wire in transformer.

I have a book for SMPS, Switchmode Power Supply Handbook 2nd, McGraw-Hill. It is difficult to me, however, could you recommend another one to me.

Thanks a lot Jim. I am happy to know one of best method from you and also good word about Newton, Sir Isaac.

Thank you, Graham for your another answer about Skynet again.

Bob.

I can do simulation tool and programming, Psim and Ascl and C language. So, I wondering that it is necessary thing for developing adaptor about

If yes, what tool is good work?

Bob.

If you haven't done it before then you have a problem clearly. It's quite an 'art' to learn SMPS design from 'scratch'. When you've done it once, it seems very easy the next time.

Also pay strict attention to the safety requirements when designing a transformer. Specifically pay atttention to *margins* and all other clearance distances. It may be easier to use triple insulated wire - that's what I do.

If you're unfamiliar with the requirements of safety standards you should talk to someone who is.

I've used PI Expert. Mainly Version 4 actually. It's very good. You can even use the derived ressults if you're not actually using their parts.

PI's aplication notes are also *excellent*. You should read most of them. You'll find many of the answers you need right there.

Graham

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All that means, these days, is that after changing a faulty immersion heater inside the domestic hot water tank you are qualified to re-connect the two wires from the heating element to the power supply.

The manner in which you make your enquiry provides more information about your status. It is THAT which contributes towards the quality of the replies you get.

I wish you all the best with your project.

On 6 Aug 2005 23:44:05 -0700, "Bob J." wroth:

Buy as many different adapters as you can find that are close to your requirements. Disassemble them, extract their circuits, and determine how much it would cost you to reproduce them. Pick the most economical few and see if you can re-design any parts of them to reduce the cost.

Each commercial adapter probably represents the work of at least four designers each with an average of ten years of experience. If you find twenty adapters to study, you will be privy to eight hundred man-years of design expertise.

There should be no shame associated with this approach. Even Isaac Newton said that his accomplishments were the result of "standing on the shoulders of giants".

Jim

Also it might be a good idea since you're new to this, to purchase one of PI's evaluation boards. They make several that are based on 'real world' type applications. It may be possible to find one that's already close to your requirements and adapt it accordingly.

Graham

Good point.

I assume the poster is in Asia somewhere. Or has access to Asian manufacturers.

There's *any number* of companies already making this stuff in volume. It's easy for them to adapt a design to meet your spec and keep it low cost by using mainly standardised parts inside.

Check out Skynet for example.

Skynet established in 1979 by Jim Liang in Taipei, Taiwan. Skynet specializes in evaluation, designing and manufacturing linear, switching power supplies and electronic ballast. With more than 25 years experiences, Skynet is proud to be the leading power supplies provider in this industry. Skynet has one of the broadest lines in the industry, ranging from 10W to 1000W. Skynet's facilities are certified by ISO 9001, BABT and T-MARK.

Skynet's switching power supplies are based on state of the art technology with strict attention to manufacturing quality. Skynet utilizes custom integrated circuits, patent circuitry, extra long life capacitors and components, which result in highly reliable, more efficient and compact power supplies. Skynet's power supplies are also recognized and listed by UL, CSA, TUV, and VDE to assure top quality and safety.

Graham

Buy doing this, be careful not to reproduce a patented design. I doubt there are any in this field of work, but you never know...

Unfortunately, It is about the best book there is.

You might find more specific information in application notes from suppliers of ferrites and controller chips. A copy of the relevant safety standards is very important too, to determine the proper layout.

Philips - which may now be "Ferroxcube" - had some very good design guides on planar transformer design. Yup, it's ferroxcube now:

Planars are good for small-ish power supplies that need mains isolation and are not supposed to cost anything. Well, I like them.

Without experience, this will be hard to do.

You might as well consider CHEATING: Get quotes from a specialist manufacturers of that kind of adapter and if they are less that $6, then buy those - unless of course you are the guy the specialist manufacturer is asking for quotes??