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GREAT-Terry
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CEO
re: Power Tip 52: Making over the wall wart
GREAT-Terry   10/1/2012 11:08:40 AM
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It is a good idea to use "quasi-resonant flyback" in low power wallwart design. It circuit is so simple! How much can be further reduced?

Hughston
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CEO
re: Power Tip 52: Making over the wall wart
Hughston   10/4/2012 3:27:58 PM
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This doesn't look much more expensive than a linear wall wart. A linear would have the input fuse, transformer, rectifier on the secondary, large filter cap and a load resistor to drain the cap charge. The rectifier is not always in the wall wart; it can be in the charged product. A more efficient way to use a linear wall wart is to give it a higher source impedance and put a switch in the product being charged and pulse charge with the input.

WKetel
User Rank
Rookie
re: Power Tip 52: Making over the wall wart
WKetel   10/4/2012 12:37:59 AM
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The one more easy way to cut losses, at this point, is to add a switch so that the AC input can be switched off. That should have been mandated 40 years ago when the wall warts were starting to appear. Of course it would have been a serious hardship and it would have raised the cost of each unit by about 15 cents, but consider how much wasted power it would have saved. At some point the folks who make all of the laws need to tell the whiners and complainers to "shut up, because we don't care about the profit that you lose." If it is OK to mandate all kinds of efficiency increases in cars, which requires all manner of new innovations, it should certainly have been OK to mandate on/off switches, which were nothing new, and very well understood.

Robert K
User Rank
Blogger
re: Power Tip 52: Making over the wall wart
Robert K   10/5/2012 1:48:34 PM
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Try these links, the last two in the article are wrong. http://www.ti.com/tool/pmp7389 http://www.ti.com/tool/pmp8286

nicolas.mokhoff
User Rank
Rookie
re: Power Tip 52: Making over the wall wart
nicolas.mokhoff   10/24/2012 1:17:36 PM
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Thanks, Robert. Links in story have been corrected.



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