What are the pros and cons of the various DC-DC step-up converter designs (say, 12V to 18V, 50 watts total)?
I could use one for my old laptop (366 mhz, it wants 18V @ 2.7A).
I went to this website:
and I see there are CUK converters, Boost, Buck Boost, etc.
My intuition tells me there are trade-offs in efficiency, ease of construction, cost, consistency and durability between each of these methods.
Any suggestions guys?
Your link was cut off - try using "tinyurl.com" to give us something to look at.
I haven't seen a design touted as a Cuk converter outside of textbook pages; the idea is great for reducing ripple: input, otuput, or both.
Are you in need of general learning? A single device? A design-your-own
1k/mo production solution? Is your need non-isolated? _________________________________________Your link was cut off - try using "tinyurl.com" to give us something to look at.
I haven't seen a design touted as a Cuk converter outside of textbook pages; the idea is great for reducing ripple: input, otuput, or both.
Are you in need of general learning? A single device? A design-your-own
1k/mo production solution? Is your need non-isolated? _________________________________________
Eek! Well, basically the one at the end here:
I'd like to make this a learning experience. (Otherwise, I'd just buy one.) And hopefully something that can provide 50W, steady enough so as not to fry my laptop...
A single device, I'm still a beginner as far as electronics are concerned... definitely not 1k/mo.
Then again, I don't even know what I need to learn! What are the advantages of Buck vs. Boost, etc? Cuk is out? Why?
I remember a DC-DC converter on the back of Forrest Mims' 555 handbook, but it needed a Radio Shack 120VAC/12VAC stepdown transformer. (I remember building it many years ago, and I only got about 50V out of it. Was expecting 120V...)
Flyback booster:
Low parts count. Uses "off the shelf" parts. Vout must be more than Vin. Wide supply range. Not good for multiple outputs.
Flyback isolated:
Lowish parts count. Vout vs Vin can be anything. Wide supply range. May need a largish core for a given power. Large ripple currents. Fair tracking on multiple outputs.
Buck:
Low parts count. Off the shelf parts. Vout must be less than Vin. Not good for multiple outputs.
Non-isolated Cuk:
Good if you want to invert the sign of the voltage. Off the shelf parts. The coupling capacitor can be troublesome. Can make equal +/- supplies with good tracking.
Isolated Cuk:
Much like isolated flyback without the large ripple currents. Good tracking on multiple outputs. Special magnetics.
Single ended forward converter:
Use a flyback.
psudo-squarewave, forward, voltage fed, isolated:
Vout vs Vin can be almost anything. Low output side ripple currents. Small cores for a given power. Poor tracking on multiple outputs. Narrower Vin range.
Psudo-squarewave, forward, current fed version:
Same as above but low input ripple. Fair to good tracking on multiple outputs.
Resonant isolated:
Kind to switching parts. Needs more parts.
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