Super Low Profile >130W SMPS ???

Interconnection method expected for the AC line input?

Where'd the heatsink come from, if the profile is so critical?

RL

120VAC 60Hz AC wire goes directly to the PCB. No connectors. The heatsink is part of the structure.

I'm just trying to make sure I can't get this sort of smps off the shelf. I really hate it when after weeks of engineering something... somebody tells me it's available at Walmart for $29.99.. :P

D from BC snipped-for-privacy@comic.com British Columbia Canada

One way would be to use a number of smaller SMPS's

Look at the Vicor 'factorized power' products - these are well suited to conduction cooling and require minimal caps on the output

conduction cooling and

D'oh!... I'll try smaller smps's that share the power.. Thanks

D from BC snipped-for-privacy@comic.com British Columbia Canada

Look into ZVS or ZCS resonant converters. Because the inductor value is very low you can use E and I cores to create a transformer using PCB traces as windings.

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Exactly! Don't design, specify! Especially something like a doohickey that would need safety approvals!

I don't think you can get a 3-wire cord strain relief in an 8mm profile. Fixed line cord is kind of retro for such a 'space-age' low profile design. How much does the target vehicle weigh?

If it's two wire, don't forget to include the reinforced insulation requirement.Sorry, I just can't seem to take this design target seriously.

RL

I believe this is just the kind of issue that has landed this "specification" in the OP's lap. Irresponsible specs result in overpriced results.

RL

I think I've seen flat wire for some irons and some kitchen appliances. IIRC I've also seen flat extension cord wire meant to go under rugs. I doubt I'll get stuck on a strain relief problem.

There's no weight constraint. It's not getting blasted into space :)

An 8mm high offline smp >130W I believe is doable. (Height excluding the heat sink.) Say planar magnetics used.. Possibly multiple smps summed together and a topology that doesn't use fat electrolytics.

D from BC snipped-for-privacy@comic.com British Columbia Canada

Yup... I'm certainly looking at ZCS topologies and planar magnetics.

D from BC snipped-for-privacy@comic.com British Columbia Canada

I think it's only one of the simplest of a host of issues that you and the specifier are ignoring.

'Open frame' and fixed line cords (among other things) don't usually mix, as the open frame must be enclosed in a final product safely and effectively - the mechanical, thermal and electrical features supporting and complimenting each other.

You don't just say: 'We've got 8mm to fit the power supply in - here'.

RL

The smps is being 'buried' in my product idea. I say, If it's tough to do..it's worth doing... Like going to the moon.

D from BC snipped-for-privacy@comic.com British Columbia Canada

Perhaps I should point out that 'going to the moon' was not a commercial venture.

It's your nickel.

RL

I understand liking the challenge. What do you intend on using for the magnetics? Even at say 30 W per core.

Magnetics is not my strong area..

Is there a program entitled 'Magnetics Simulation for Dummies'. :) That way I can play with gaps, custom core dimensions, power loss, frequency and current. At least I can glue pieces of ferrite together.. :)

An air coil naturally makes a toroidal field pattern.. Using a core to contain that field pattern into a 8mm high flat pancake shape...well..AFAIK magnetic field lines don't do 90 degree turns very well. Taking flattening to the extreme, I don't think a 3D magnetics phenomenon can be forced to act like a 2D phenomenon.

D from BC snipped-for-privacy@comic.com British Columbia Canada

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You can make a very flat transformer with a "matrix transformer". Imagine an array of, lets say 100 RF bead sized cores layed out on a

10x10 pattern. Each core has two wires running through the hole. One wire snakes through the entire array one by one. The other is 10 wires each of which pass through 10 cores and then get paralleled. This gives you a 10:1 ratio transformer.

Cool... Good Ol Matrix as a fix.. :)

"Unfortunately, no one can be told what the Matrix is. You have to see it for yourself. This is your last chance. After this there is no turning back. You take the blue pill, the story ends, you wake up in your bed and believe whatever you want to believe. You take the red pill, you stay in Wonderland, and I show you how deep the rabbit hole goes.... " from The Matrix

I found some related patents..

I've never heard of a matrix transformer.. Thanks

D from BC snipped-for-privacy@comic.com British Columbia Canada

Flat Transformer Technology Corp.

"Flat Transformers for Low Voltage, High Current, High Frequency Power Converters" Holmes and Sum, HPFC'96.

"How to Design a Sophisticated 200 watt to 600 watt Brick dc-to-dc Power Converter" Sum and Lau PCIM Europr'99

RL

Given spare time and, you could google for coaxial transformers, too.

Another matrix link is the FMTT Corp.

RL