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Registered Member #540
Joined: Mon Feb 19 2007, 07:49PM
Location: MIT
Posts: 969
I'm surprised to see that quasi resonant designs have hit the market. They tend to be more of a research like thing since they are fairly new. They allow you to get really high efficiencies at high frequencies. The high freqs allow you to push your entire circuit into a smaller package. I'll be working with something similar this summer (fully resonant designs though).
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
Typical Apple, ploughing R&D money into making the world's sexiest wall wart, and then selling it at a huge markup.
I have one of the UK version here. It is the size and shape of an ordinary British appliance plug, and I think they must have redone the PCB layout to make that happen. Lesser wall warts keep the same casing and change the prongs.
Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061
I have a S*m*ung one here which is very similar. As it has failed with the infamous dodgy connector syndrome I might take it apart and find out how it works.
Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
Well, the quasi resonant design is really old and is used in the horizontal output circuit of TV sets since the first transistorised designs with a HOT. However, I don't see what is the exact purpose of Q1 in the schematic - anyone dare to guess?
Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061
Aaaand this week's project:- Make a mini SMPS based on the same technology that runs a full PC motherboard off a little PCB complete with all standard ATX voltages.
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Inside an Iphone charger
